CA1098268A - Method and apparatus for molding optical plastic lenses of the standard and bifocal type - Google Patents
Method and apparatus for molding optical plastic lenses of the standard and bifocal typeInfo
- Publication number
- CA1098268A CA1098268A CA296,512A CA296512A CA1098268A CA 1098268 A CA1098268 A CA 1098268A CA 296512 A CA296512 A CA 296512A CA 1098268 A CA1098268 A CA 1098268A
- Authority
- CA
- Canada
- Prior art keywords
- lens
- accordance
- bifocal
- molds
- mold
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D11/00—Producing optical elements, e.g. lenses or prisms
- B29D11/00009—Production of simple or compound lenses
- B29D11/00028—Bifocal lenses; Multifocal lenses
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D11/00—Producing optical elements, e.g. lenses or prisms
- B29D11/00009—Production of simple or compound lenses
- B29D11/0048—Moulds for lenses
- B29D11/00528—Consisting of two mould halves joined by an annular gasket
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S425/00—Plastic article or earthenware shaping or treating: apparatus
- Y10S425/808—Lens mold
Abstract
ABSTRACT OF THE DISCLOSURE
A bifocal lens is produced on either a previously formed blank lens, or completely in a singular casting between two molds. The bifocular lens is obtained by supporting a bifocal lower mold having a recessed bifocal well area on its concave surface and filling the lower mold with a resin material. By positioning an upper mold in vertically spaced relationship to the lower mold, the resin material is displaced to extend between the overlapping surfaces of the molds to form the configuration of the bifocal lens with a bifocular portion on the convex lens surface corresponding to the bifocal well on the lower mold. Curing of the. resin material situated between the molds and cooling the resin material and the molds forms the complete lens.
Thereafter, a separating of the bifocal lens from between the molds leaves the bifocal lens in a position to be completed and installed in a pair of eyeglasses.
A bifocal lens is produced on either a previously formed blank lens, or completely in a singular casting between two molds. The bifocular lens is obtained by supporting a bifocal lower mold having a recessed bifocal well area on its concave surface and filling the lower mold with a resin material. By positioning an upper mold in vertically spaced relationship to the lower mold, the resin material is displaced to extend between the overlapping surfaces of the molds to form the configuration of the bifocal lens with a bifocular portion on the convex lens surface corresponding to the bifocal well on the lower mold. Curing of the. resin material situated between the molds and cooling the resin material and the molds forms the complete lens.
Thereafter, a separating of the bifocal lens from between the molds leaves the bifocal lens in a position to be completed and installed in a pair of eyeglasses.
Description
B~CKGRO~ND OF THE INV~NrION
Field of the Invention The present lnvention pertains to the manufac-ture of ophthalmic lenses and in particular to bifocal -~
ophthalmic lenses. 5 Blfocal lenses require a distance correction, an astigmatic correction, an axis for the astigmatic correction ranging from 0 to 180, proper decentra- -tion, and a reading correction. Because of the nearly infinite number of possible combinations of these 10 corrections, it has become both impossible and unfea-sible for the laboratory to stock finished bifocal prescription lenses. Therefore, the manufacturer usually supplies the laboratory wlth a semi-finished blank. This blank has a finished front surface and a 15 semi-flnished rear surface, the rear surface being ground and polished to achieve the finished prescription, and the front surface containing a distance curvature and a bifocal addition. Conceivably, the manufscturer could, with the same effort~ cast the 20 finished prescription, but the econo~ics o} the industry : ,:
.':
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do not permit the casting of individual prescriptions ~-by the manufacturer, and, instead, he mass-produces serni-finished blanks.
The laboratory which is oriented to filling individual prescriptions, therefore, grinds and S
polishes the rear or concave surface of the concave-convex lens to con~orm to the finished prescription by taking into account the distance correction, the astigmatic correction, decentration, the axis of the ;~
astigmatic correction and the biiocal addition. 10 Ideally, it would be best for the laboratory to cast its own finished prescription rather than to buy the semi-finished blank, but the lack of technology at the laboratory operation and the economics of the operation lS simply do not permit the casting of individual pre- 15 scription lenses.
Some of the problems involved ln the casting of plastic lenses are that the plastic shrinks by about I5%, and that the mass of the cast plastic generates an exothermic reaction. The normal prescription 20 ;
requires casting two dissimilar curvatures, front and back, and this in turn ~ay produce lenses ha~ing a grèater center thickness and thinner edge thickness, or greater edge thickness and thinner center thick-ness. This further complicates~the casting technique 25 because the dissimilar center and edges must both shrink the sarne 15% and the technique used to have the
Field of the Invention The present lnvention pertains to the manufac-ture of ophthalmic lenses and in particular to bifocal -~
ophthalmic lenses. 5 Blfocal lenses require a distance correction, an astigmatic correction, an axis for the astigmatic correction ranging from 0 to 180, proper decentra- -tion, and a reading correction. Because of the nearly infinite number of possible combinations of these 10 corrections, it has become both impossible and unfea-sible for the laboratory to stock finished bifocal prescription lenses. Therefore, the manufacturer usually supplies the laboratory wlth a semi-finished blank. This blank has a finished front surface and a 15 semi-flnished rear surface, the rear surface being ground and polished to achieve the finished prescription, and the front surface containing a distance curvature and a bifocal addition. Conceivably, the manufscturer could, with the same effort~ cast the 20 finished prescription, but the econo~ics o} the industry : ,:
.':
,,;;
do not permit the casting of individual prescriptions ~-by the manufacturer, and, instead, he mass-produces serni-finished blanks.
The laboratory which is oriented to filling individual prescriptions, therefore, grinds and S
polishes the rear or concave surface of the concave-convex lens to con~orm to the finished prescription by taking into account the distance correction, the astigmatic correction, decentration, the axis of the ;~
astigmatic correction and the biiocal addition. 10 Ideally, it would be best for the laboratory to cast its own finished prescription rather than to buy the semi-finished blank, but the lack of technology at the laboratory operation and the economics of the operation lS simply do not permit the casting of individual pre- 15 scription lenses.
Some of the problems involved ln the casting of plastic lenses are that the plastic shrinks by about I5%, and that the mass of the cast plastic generates an exothermic reaction. The normal prescription 20 ;
requires casting two dissimilar curvatures, front and back, and this in turn ~ay produce lenses ha~ing a grèater center thickness and thinner edge thickness, or greater edge thickness and thinner center thick-ness. This further complicates~the casting technique 25 because the dissimilar center and edges must both shrink the sarne 15% and the technique used to have the
- 2 .~ :
molds conform to these dissimi]ar shrinkages is part of the art of castingplasticprescription lenses.
Furthermore, the mass of plastic cast generates its ^~
own exothermic reaction and it is necessary during the initial portion of the curing cycle to introduce heat 5 to initiate reaction and during the latter parts of the reaction to remove heat in order to keep the reaction under control. However, casting thin films and parallel surfaces can easily be accomplished since the exothermic reaction is negligible, the surfaces 10 are substantially parallelj and the 15% shrinkage causes no appreciable reduc~ion in mass.
Thus, if a laboratory could make a finished bifocal lens by casting thin films, it mlp,ht avoid the difficult task of grinding and polishing semi-finished 15 blanks provided by the manufacturer.
Description of the Prior Art The prior art has disclosed a method of adding a correction to a molded plastic lens by adding a thin le~el of resin. However, ~he only concern is with 20 conventional type lense,s, those with only one focus, -~
and furthermore, with changing the curvature of the lens. The bifocal lens, which has two foci, is not possible of production with prior art methods and does .
not disclose how two different foci can be effected by 25 ;~
adding a resin layer to an existing lens.
~;
molds conform to these dissimi]ar shrinkages is part of the art of castingplasticprescription lenses.
Furthermore, the mass of plastic cast generates its ^~
own exothermic reaction and it is necessary during the initial portion of the curing cycle to introduce heat 5 to initiate reaction and during the latter parts of the reaction to remove heat in order to keep the reaction under control. However, casting thin films and parallel surfaces can easily be accomplished since the exothermic reaction is negligible, the surfaces 10 are substantially parallelj and the 15% shrinkage causes no appreciable reduc~ion in mass.
Thus, if a laboratory could make a finished bifocal lens by casting thin films, it mlp,ht avoid the difficult task of grinding and polishing semi-finished 15 blanks provided by the manufacturer.
Description of the Prior Art The prior art has disclosed a method of adding a correction to a molded plastic lens by adding a thin le~el of resin. However, ~he only concern is with 20 conventional type lense,s, those with only one focus, -~
and furthermore, with changing the curvature of the lens. The bifocal lens, which has two foci, is not possible of production with prior art methods and does .
not disclose how two different foci can be effected by 25 ;~
adding a resin layer to an existing lens.
~;
- 3 -~ ' . ' . "
.. . .
The prior art also discloses a method for casting multifocal lenses. However, this method re-quires two mold portions held together by a gasket, one of the molds having a recessed portion, so as to provide a bifocal effect. The lîquid plastic is 5 injected between the two mold portions, cured and cooled thus creating an entirely new lens, whereas Applicant simply transforms an existing lens into a bifocal lens. Some of the problems with using gaskets are that they are expensive and that the 10 assembly of the molds and gaskets require expensive hand labor.
Another prior art method of casting multi-ocal lenses utilizes the base blank whose curvature is only about half the curvature of the predetermined 15 power of the composite lens. This requires, in order to complete casting the bifocal, the casting of a relàtively large amount of mass of non-parallel sur-faces which presents the ensuing problems of shrink-age and heat dissipation. 20 Objects of the Inventi.on ' :'' It is the primary object of the present invention to provide a new and novel method and means for the manufacture of a lens having the bifocular portion cas~ in the lens in prescribed position 5 relative to the astigmatic axls.
It is yet another object of the present invention to provide new and novel apparatus for the manufacture of ophthalmic lenses. -~
It is yet a further object of the present 10 invention to provide a method ancl means of making a bifocal lens by casting and incorporating a thin -parallel film onto and with an existing lens.
It is yet another object of the present invention to simplify the method and means of 15 producing a multlfocused lens.
It is still a further object of the present ~;~
invention to provide a new and novel holder for casting ophthalmic plastic lenses of the standard and bifocal types, which delineates the necessity 20 and cost of utilizing gaskets. -Summary of the Invention In accordance with one embodiment of the present invention, a complete bifocal lens is pro~
duced withou~ the need to first supply a previously formed blank lens. This permits the lens manufac- 5 turer to easil~ produce a lens to the exact require-mens set forth in the prescription.
The bifocal lens is produced by supporting a bifocal lower mold having a recessed bifocal well area on its concave surface and filling the lower 10 mold with a resin ma~erial. Thereafter, positioning an upper mold in vertically spaced relationship ~o the lower mold, whereby the resin material is displaced to extend between the overlapping surfaces of the molds to form the configuration of the bifocal lens 15 with a bifocular portion on the convex lens surface corresponding to the bifocal well on the lower mold.
By curing the resin material situated between the molds, and then cooling the resin material and thP molds, a bi~ocal lens is produced. The bifocal lens is then 20 separated from between the molds.
The holder for the molds is designed for visually indicating the positional angular degree of orientation of the bifocular portion relative to the -astigmatic axis being formed on the bifocal lens in 25 prescribed position relative to the astigmatic axis.
The aligning of the astigmatic axis of the upper mold relative to the recessed well in a predetermined orientation is such, that the bifocular portion is formed on the bifocal lens in a desired position S dependent upon the prescribed needs of the prospective 5 user thereof.
In accordance with another embodiment of the present invention, the laboratory is provided with a single vision lens, which already contains the distance portion and the astigmatic correction, and 10 a bifocal mold, which has the same radius of curva-ture as does the front surface of the lens and which has a recessed portion, so that two different thick-nesses of film can be deposited on the lens. A small amount of a liquid plastic material is deposited in 15 the bifocal mold held concave surface-up. The lens is then placed in the mold, thereby spreading the liquid so it completely fills the space between the lens and the mold.
A suitable support is preferably used to hold 20 the lens a few thousandths of an inch above -the mold, to hold the astigmatic correction at its proper angle, and to provide the proper decentration of the bifocal portion. The combined assembly is then run through a curing cycle in an oven. After curing, ~he assembly 25 is allowed to cool. By inserting a razor at the edge ~;
of the point of contact between the lens and the mold, the new compound lens will separate readily from the mold, the lens including therewithin the newly cast bifocal portion, which has the desired distance cor-rection, the astigmatic correction at the proper axis, decentration, and the reading correction, all in the 5 proper location.
The present invention also performs all of the functions of the presently used gasket. It orients the convex lens surface and the concave mold surface so that they remain one directly over the other and 10 so that they remain parallel; it maintains a separa-tion between the mold and the lens; it retains the plastic liquid in the mold; and it allows shrinkage to occur.
Brief Description of the Drawings 15 The foregoing and other objects, features and advantages of the present invention will become more apparent to those skilled in the art from a reading of the detailed description hereinafter, when con-sidered in conjunction with the accompanying drawings, 20 wherein FIG. 1 is a perspective view of a first embodiment, in exploded relationship, of a new assem-bly for forming of lenses comprised of a holder having cooperating upper and lower molds; 25 p~
FIG. 2 is a slightly enlarged sectional view of the initially assembled holder having the lower mold positioned thereon and showing also the deposit of the liquid plastic material;
FIG. 3 is a sectional view similar to FIG. 2 5 ~ ;
having the upper mold positioned thereon;
FIG. 4 is a top plan view of a lens formed with the apparatus illustrated in FIGS. 1 through 3;
FIG. 5 is a top plan view of a holder illustra~ing another embodiment of the present 10 invention in the manufacture of a bifocal lens;
FIG. 6 is a second view similar to FIG. 2 showing the formation of a bifocal lens with the deposit of the liquid plastic material for bonding to a previously formed lens; 15 FIG. 7 is a fragmentary sectional view including the positioning of the lens on the holder and the movement of the liquid thereupon; ~ :
FIG. 8 is a fragmentary sectional view of the : 20 completed bifocal lens; 20 Fig. 9 is a top plan view of a bifocal lens ~ ::
- formed with the apparatus illustrated in FIGS. 5 ;
through 7; ~:
FIG. 10 is a view similar to FIG. 7 illustrating a modified step in the process; 25 ':
_ 9 _ . ~:
FIG 11 illustrates another embodiment of the present invention and is a view similar to FIG. 6 except that the complete bifocal lens is fabricated without the use of a previously formed lens; and FIG. 12 is a view similar to FIG. 3 illus- 5 trating the formed lens therein.
_etailed Description of the Preferred Embodiment :
Referring now ~o the drawings and, more particularly, to FIGS. 1 through 4, there is shown a first embodiment of an apparatus 10 ~or the 10 manufactur.ing of a lens 12 that is ~ormed having a pair of oppositely disposed spaced apart surfaces 14 and 16. Sur~ace 14 being the one having the convex ; .
spherical curvature, and the surface 16 having the inner concave cylindrical curvature. The surfaces 15 14 and 16 are connected by an outer end 18 extending therebetween and terminate in an outer edge 20, which as illustrated in FIG. 4, may have a clrcular con- :
figuration.
The lens 12 is for~ed having an astigmatic axis 20 22 illustrated by the b,roken lines in FIG. 4. To manufacture lens 12, there is provided a holder 24 which is utilized in conjunction with a lower or bottom .
mold 26 and a upper or top mold 28. The configuration of the molds 26 and 28 is such that lenses 12 can be 25 :
cast with constant front curvatures over an extended ' range of foci and astigmatic corrections. These lenses 12 may be made of glass, plastic or any other suitable material known in the art.
The mo'lds 26 and 28 are preferably made of 5 either glass or of electro-formed metal. The lower mold 26 includes an outer surface 30, which may be convex and an inner surface 32 which may be concave, ~ -with an intermediate or end wall 34 joining together the oppositely disposed surfaces 30 and 32. 10 '~
, The end wa'll 34 prefera'bly has a circular ;~
configuration which may substantially coincide with '-`
the outer edge 20 formed on lens 12. The upper mold . ~ i .. .
28 includes an outer surface 36 which may have a con~
cave configuration. An intermediate or end wall 40 15 '~
joins together the oppositely disposed surfaces 36 and 38. The end wall 40 preferably has a circular configuration, which as illustrated in FIG. 3, may '~
:
exceed the diameter de~ined by the outer edge 20.
To permit the manufacture of the lens 12, having 20 various selected angles of curvature, depending upon the configurations of molds 26 and 28 that are selec-ted, -the apparatus consisting of the holder 24 is utilized. The holder 24 includes a base portion 42 which has a bottom surface 44 on which ~he holder 2425 may be supported during use thereof. Base portion 42 ~, has an outer circumferentially extending side wall 46 , `- ~
which may have a circular or other configuration. An upper surface 48 extends in substantially parallel spaced rel.ationship to the bottom surace 44 and there may be provided a recess or through bore 50 extending intermediate the surfaces 44 and 48. 5 Support means 52 is operatively associated with the base portion 42 of the holder 24 so as to maintain the molds 26 and 28 in removably supportive vertically spaced position relative to each other, such that the lens 12 is formed intermediate the over- 10 lapping opposing surfaces 32 and 36 of the molds 26 and 28, respectively. The holder 24 may be fabricated from any suitable material; e.g., any metal capable of withstanding the temperatures to which the molds 26 and 28 are to be subjected. 15 ~
The support means 52 rnay be formed from a .
plurality of support posts 54 tha~ may be integrally foxmed with and extend upwardly from the upper surface 48 o~ the base portion 44. Each support post 54 may be ~ .
defined by a front surface 56 and a rear surface 58 20 that extend in spaced relationship to eac'n other.
Each post 54 may be dimensioned such that the rear sur-face 58 coincides with the side wall 46 of base portion 42 and terminates in a top or distal end 60.
Yhe support posts 54 may be circumferentially 25 and substantially equally spaced from each other. The support means 50 further comprises a lower step 62 provided in each of the support posts 54 for use in conjunction with the lower mold 26. An upper step 64 is similarly provided in each of the support posts 54 and similarly faces inwardly so as to be capable of removably supporting the upper mold 28 in the position 5 illustrated in FI&. 3. The steps 62 and 64 being in :~
substantially parallel relationship to each other so ~:
as to obtain a controlled thickness of the lens 12 to : ~ ~
be formed intermediate the overlapping molds 26 and 28. ~- :
To maintain the molds in proper position 10 . ~ .
relative ~o each other during the formation of lens 12, there is provided a vertically extending shouldPr 66 extending intermediate the lower step 62 and upper step 64, on each of the support posts 54. To prevent inadver~ent movement of upper mold 28, there is pro- 15 vided a substantially vertically extending shoulder `~
68 extending between upper step 64 and distal end:60. .
Shoulder 66 is appropriately dimensioned to `~
confine the end wall 34 of lower mold 26. Shoulder 68 ; .:
is appropriately dimensioned to confine the end wall 20 40 of upper mold 28. As illustrated in FIGS. 2 and 3, the shoulder 68 extends outwardly beyond shoulder 66 :~
to accommodate the molds 26 and 28 having differing outer diameters. Each of the steps 62 and 64 is down~
wardly and lnwardly inclined to subs~antially conform 25 :
to the angular configuration of the molds 26 and 28.
In this manner, the holder 24 is capable of being utilized to form lenses having various partic-ular configurations. The process by ~hich a partic-ular lens 12 is manufactured is that a previously selected lower mold 26 is positioned on the support 5 posts 54 and retained in place by the lower steps 62.
Once this is accomplished ~here is a filling of the lower mold 26 with a resin material 70. In its liquid form the resin material 70, as illustrated in FIG. 2, is now ready to be initially formed. The initial 10 ~ -formation of the lens 12 takes place by positioning the upper mold 28 in vertically spaced relationship to the lower mold 26. This is accomplished since the upper steps 64 are dimensioned to readily receive the upper mold 26 thereon, whereby the resin material 70 15 is displaced to extend between the overlapping sur-faces 32 and 36 of the molds 26 and 28, respectively, to form the configuration of the lens 12. ;
In the assembled position of the molds 26 and 28, as illustrated in FIG. 3, there may occur a curing 20 of the resin material 70 which may take place in an oven 72, illustrated in phantom, and a subsequent cooling of the resin material 70 to a temperature at which a separating of the lens 12 from between the molds 26 and 28 may take place. 25 ., :
A second embodiment of the present invention, and, in par~icular, of the formation of a lens having a bifocular portion or segment, is illustrated in , ~ :
FIGS. 5 through 10, wherein similar parts are denoted ~ ~
by similar reference numerals. 5 -~ -In this embodiment, a previously fabrica~ed lens 12A, which might have been manufactured in ~ ~
accordance with the embodiment illustrated in FIGS. 1 ~ ~:
through 4, is now utilized to produce a bifocal lens 74A, as illustrated in FIG. 8. In effect, lens 12A 10 :
forms the upper mold previously described with respect ~ ~
to FIGS. 1 through 4. ~The holder 24A is similarly ~:
utilized in that the lower mold 26A is supported by posts 54A and further includes a bifocal welI area or ~ .
por~ion 76A. The bifocal well area 76A, by its config 15 ;~
uration and orientation relative to the astigmatic -,~.
axis 22A, will determine~particular characteristics of the bifocal lens 74A. The bifocal ~lens 74A lS com-prised of lens 12A and a bifocular portion or segment 78A that is formed in the well 76A and further includes 20 a thin layer 80A which extends over the outer spherical conve~ curved surface 14A of lens 12A. The thin:layer 80A terminates in an outer margin 82A, as illustrated : .
in FIG. 8.
. The method of manufacturing t'ne bifocal lens 74A 25 includes the placing of the bifocal mold 26A in :
supportive position within the holder 24A. The lens 12A may be a single focus lens. The bifocal mold 26A
rests atop the lower steps 62A with the concave sur- ~
face 32A facing upwards. The concavity of each mold -26A has formed therein a recess or curvature which dif-fers from that of the lens surface 14A, to receive 5 additional material to create the bifocal effect.
The next step is ~o locate and position the -"stock" lens 12A over the mold 26A, the convex front ~ -surface 14A of ~he lens 12A being directed against the concave surface 32A of mold 26A. The lens 12A being 10 supported by the upper seats or steps 64A of the sup-port posts 54A. The upper steps 64A are so positioned with respect to the lip of the mold as to provide a narrow space between lens 12A and mold~surface 32A.
Care must be exercised in this step to avoid trapping 15 .
air bubbles between the liquid and the lens 12A, or in the liquid 70A. T~ere should be used a sufficient amount of the resin 70A that the placing of the lens 12A ~
causes the resin 70A to be spread evenly to form a thin layer of the resin between the mold 26A and the lens 12~. 20 Excess material, if any, can be scraped away ;~
: -using the marginal edge of the "stock" lens 12A as a guide, or ground away. When the resin is flooded into mold 26A, the spacing between the lens 12A and mold 26A
is a matter of a few thousandths of an inch. However, 25 at the recessed portion 76A in the concave face 32A of the mold 26A, there will be a thicker mass with a '',:'' '' - 16 - ~
2~
:, :
different curvature, to thereby provide the bifocal effect desired. The importance of the horizontal portions of the upper steps 6~ being parallel can now be appreciated. It allows the lens 12A and mold 26A to rest parallel to each other and prevents the 5 resultant bifocal lens 74A from having a cast-in prism. ;
Thereafter, a predetermined amount of a -castable resin, as at 70A, is placed onto the concave portion 32A. The amount of resin used is dependent 10 upon the desired diameter and thickness of the bifocal lens 74A sought to be obtained. Usually, about 4 to ;~
6 cc. of the resin will be the appropriate amount.
The preferred resin is CR 39 plastic, but tests using ` ~ ` j :
a 100% solution of CR 39 indicate~that the boiling 15 characteristics of such a bifocal lens are not adequate.
Therefore, it was found necessary to introduce quanti-ties~of methyl methacrylate or ethyl methacrylate to the CR 39 in order to improve the boiling character~
istics. 20 These results were obtained by numerous laboratory tests, and a~e shown in Table I. The tests were made under three types of boil.ing conditions:
one and a half hours of continuous boiling; two hours ;
of continuous boiling; and two hours of intermittent 25 boiling. (Since plastic lenses are tinted in boillng water solutions of dyes, boiling was used as the basis ~ 17 2~
for the tests.) The major causes of lens failure were: -crazing resulting from insufficient cure of the applied portion of the bifocal; delamination caused by -insufficient adhesion between the applied portion and `
the original base lens; and splits caused by an uneven 5 ~ .
expansion of the applied portion and of the original :
base lens.
The materials to form the lens of the embodi- `
ment illustrated in FIGS. 5 through 10 may also be .
utilized to form the lens previously illustrated with 10 respect to the embodiment in FIGS. 1 through 4, as well as the embodiment hereinafter discussed with respect to FIGS. 11 and 12. ~ .
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~ ~ a v 1, _ 1q In order to provide for individualized astig-matic correction, as illustrated in FIG. 5, there is provided indicia means 84A operatively associated with the holder 24A so as to permit prescribed angular orientation of either the mold 26A or the lens 12A 5 ;
relative to each other so as to obtain a resultant bifocal lens 74A with a prescribed astigmatic axis 22A
relative to the bifocular portion 78A. By providing this capability, it is possible to customize the desired bifocal lens 74A since the lens 12A can be appropriately 10 turned so that the resin 70A will accumulate at the individual point or area desired.
The indicia means 84A may be provided on the -~
base upper surface 48A and include a plurality of cir-cumferentially disposed markings 86A. As indicated, 15 ~ ~-the reference orientation of 0~; 90; 180; and;270 This permits the aligning of the astigmatic axis 22A of the lens 12A relative to the recessed well portion 76A
in a predetermined orientation. In this matter, the bifocular portion 78A is formed on the lens 12A in~a 20 desired position dependent upon the prescribed needs of the prospective user thereof. By indicating visually the positionable angular degree of orîentation by the indicia means 84A, the desired adjusting may take place. :~
With particular reference to FIG. 10, shim 25 :~
means 88A may be utilized in the form of a wedge element 90A which is placed around one of the upper .
. .
support steps 64A to achieve a desired degree of decentration of the optical center with respect to the bifocal segment 78A, and to achieve ~his decentration for any angle required in any prescription. The wedge element 90A may be used on either one, two or possibly 5 three of the four support steps 64A.
The entire assembly is now placed in an air circulating oven 72A for curing. Since CR 39 cures slowly at low temperatures and quickly at high temper-atures, a variety of curing cycles are available. For 10 instance, sixteen hours at 57C(135F) and then forty ~
minutes at 82C(180F) gives a well cured bifocal lens ~ ~ ;
74A. However, it is desirable to turn over the expen-sive molds as many times as possible consistent with ;~
quality production; therefore, shorter cycles have been 15 used and have provided lenses with excellent results and full cure. Two acceptable shorter cycles are: thirty minutes at 71C(160F), thirty minutes at 77C(170F), and thirty minutes at 82C(180F) and twenty minutes at 77~C(170F), twenty minutes at 82C(180F) and twenty 20 minutes a~ 88C(190F).
After curing, the assembly is allowed to cool to about 60C(140F), and the lens 74A is then separated fom the mold 26A, the newly cast bifocal film portion 80A is integral with the original lens 12A. The resultant lens 25 74A, after edge grinding for peripheral shaping is now a complete bifocal lens, including distance correction, astigmatic correction at the proper axis, and the reading correction at the proper location, the lens also being properly decentered according to the individual prescription. One of the ways to separate the lens and the mold is to permit the assembly to cool to room temperature, and the lens 74A will separate spon-taneous- 5 ~-ly from mold 26A. Another and faster way is to insert a razor blade just at the edge of the point of contact :
between the lens 74A and mold 26A. Accordingly, the ~-finished bifocal lens 74A illustrated in FIG. 9 has the bifocular portion 78A contained onthe convex surface of 10 ~: :
the lens 74A, as illustrated in FIG. 8. The bifocular portion 78A may include a horizontally extending ledge 92A. ~ -A final embodiment of an apparatus 10B for the manufacture of a bifocal lens 76B is depicte~ in FIGS. 15 11 and 12 wherein similar parts are denoted by similar reference m ~erals. In this embodiment, the lens 76B
is formed with the bifocular portion 78B integrally formed thereon at the time of formation of the retaining :~
portion of the lens 76B. 20 The steps to fabricate the lens 76B are similar to that discussed with respect to those illustrated in FIGS. 1 through 5. Further, the holder 24B may have ~ :
thereon the indicia means illustrated in FIG. 5. In this manner, the final lens 74B is formed with a bifo- 25 cular portion 78B by having the lower mold 26B provided :
wi~h a well area 76B. The process by which a particular lens 74B is manufactured is that a previoulsy selected lower mold 26B is positioned on the support posts 54B
and retained in place by the lower steps 62B. Once this is accomp]ished there is a filling of the lower mo].d with a resin material 70B. In its liquid form 5 the resin material 70B, as illustrated in E'IG. 11, is now ready to be formed. The formation of the lens 74B
takes place by positioning the upper mold 28B in vertically spaced relationship to the lower mold 26B.
This is accomplished since the upper steps 64B are 10 dimensioned to readily receive the upper mold 26B
thereon, whereby the resin material 70B is displaced to extend between the overlapping surfaces 32B and 36B :
of the molds 26B and 28B, respectively, to form the configuration of the lens 74B irlcluding the bifocular 15 portion 78B.
In the assembled position of the molds 26B :~
and 2~B, as illustrated in FIG. 12, there is a curing of the resin m~terial 70B which may take place in an oven 72B, illustrated in phantom, and a subsequent 20 cooling of the resin material 70B to a temperature at ; ~`
which a separating of the lens 74B from between the molds 26B and 28B may -take place.
Accordingly, the embodiment of the invention illustrated in FIGS. 11 and 12 may be utilized with the 25 apparatus illustrated in FIGS. 5 and 10, thereby per-mitting orientation of the bifocular portion 78B, which may be of any predetermined geometric configuration and decentration accomplished by placing wedges on steps 64B. In this manner the pupillary distance may be varied either inwardly or outwardly, upwardly or downwardly.
S Attention is directed to the fact that the steps 5 62 and 64, in all embodiments, have been described as being disposed in respective parallel disposition; how- ~-ever, when a mold is employed which has a convex cylindrical curve 'to provide for astigmatic correction), -one pair of diametrically opposed steps 62 or 64 will lO
be disposed in a plar.e parallel to, but vertically dis-posed from the plane defined by the other pair of diametrically opposed s~eps 62 or 64. The foregoing may be accomplished by constructing the holder 24 in accordance with the above teachings. Alternatively, the 15 holder may have the construc~ion discussed previously and the steps may be modified to accomodate the convex cylindrical curve of the mold by the utilization of shim means, similar to shim means 88A, in FIG. lO. ~ ~;
The present invention permits the casting of 20 major corrections on the inner surface, and the outer -surface curvature is substantially standardized. There-fore, the number of molds required by a laboratory w111 be determined solely by the various number of diopter corrections required for the bifocular portion of the 25 completed lens structure, which is approximately 50-75 ~` :
different molds. Of course, special requirements and - 2~
conditions may arise increasing the required number of molds for a laboratory. However, if the castings were made pursuant to present state of the art methods, the -number of molds required would be astronomical. This is because the present day method is to keep the inner 5 surface constant and cast prescriptions on the outer surface.
It will thus be apparent that the present ~' invention provides a new and novel apparatus for fabricating plastic lens blanks and bifocal plastic 10 lens blanks which do not require any grinding of the astigmatic curve by an ophthamological laboratory.
Moreover, the present invention deletes the necessity of utilizing compressive gaskets placed upon upper and lower molds in the formation of said lens blanks. In 15 this regard, attention is directed to the fact that the utilization of the gaskets is quite expensive since they may only be used once and must thereafter be discarded and replaced by a new gasket when utilizing the molds to form additional lens blanks. 20 It will be apparent to those skilled in the art that the teachings of the present invention are primarily intended for use by an ophthamological laboratory. However, it is within the realm and teachings of the present invention to enable an optician 25 to fabricate the lenses within his business establish-ment, should he wish to provide the required initial investment for the method and apparatus of the present invention. :
However, the most important advantage obtained :~
by the use of the present invention is that both ophthalmic lenses and bifocal ophthalmic lenses may be 5 cast in accordance with an ophthamologist's prescrip-tion and without necessitating any grinding of the lenses to orient the astigmatic axis of said lenses to the prescribed angular orientation.
While I have shown and described the various 10 preferred embodiments of the present invention, it will be appreciated that the teachings herein will readily lend itself to many modifications, changes, combinations, and improvements by those s:killed in the art, without deviating from the present invention or the teachings 15 :
hereof.
:: :
.. . .
The prior art also discloses a method for casting multifocal lenses. However, this method re-quires two mold portions held together by a gasket, one of the molds having a recessed portion, so as to provide a bifocal effect. The lîquid plastic is 5 injected between the two mold portions, cured and cooled thus creating an entirely new lens, whereas Applicant simply transforms an existing lens into a bifocal lens. Some of the problems with using gaskets are that they are expensive and that the 10 assembly of the molds and gaskets require expensive hand labor.
Another prior art method of casting multi-ocal lenses utilizes the base blank whose curvature is only about half the curvature of the predetermined 15 power of the composite lens. This requires, in order to complete casting the bifocal, the casting of a relàtively large amount of mass of non-parallel sur-faces which presents the ensuing problems of shrink-age and heat dissipation. 20 Objects of the Inventi.on ' :'' It is the primary object of the present invention to provide a new and novel method and means for the manufacture of a lens having the bifocular portion cas~ in the lens in prescribed position 5 relative to the astigmatic axls.
It is yet another object of the present invention to provide new and novel apparatus for the manufacture of ophthalmic lenses. -~
It is yet a further object of the present 10 invention to provide a method ancl means of making a bifocal lens by casting and incorporating a thin -parallel film onto and with an existing lens.
It is yet another object of the present invention to simplify the method and means of 15 producing a multlfocused lens.
It is still a further object of the present ~;~
invention to provide a new and novel holder for casting ophthalmic plastic lenses of the standard and bifocal types, which delineates the necessity 20 and cost of utilizing gaskets. -Summary of the Invention In accordance with one embodiment of the present invention, a complete bifocal lens is pro~
duced withou~ the need to first supply a previously formed blank lens. This permits the lens manufac- 5 turer to easil~ produce a lens to the exact require-mens set forth in the prescription.
The bifocal lens is produced by supporting a bifocal lower mold having a recessed bifocal well area on its concave surface and filling the lower 10 mold with a resin ma~erial. Thereafter, positioning an upper mold in vertically spaced relationship ~o the lower mold, whereby the resin material is displaced to extend between the overlapping surfaces of the molds to form the configuration of the bifocal lens 15 with a bifocular portion on the convex lens surface corresponding to the bifocal well on the lower mold.
By curing the resin material situated between the molds, and then cooling the resin material and thP molds, a bi~ocal lens is produced. The bifocal lens is then 20 separated from between the molds.
The holder for the molds is designed for visually indicating the positional angular degree of orientation of the bifocular portion relative to the -astigmatic axis being formed on the bifocal lens in 25 prescribed position relative to the astigmatic axis.
The aligning of the astigmatic axis of the upper mold relative to the recessed well in a predetermined orientation is such, that the bifocular portion is formed on the bifocal lens in a desired position S dependent upon the prescribed needs of the prospective 5 user thereof.
In accordance with another embodiment of the present invention, the laboratory is provided with a single vision lens, which already contains the distance portion and the astigmatic correction, and 10 a bifocal mold, which has the same radius of curva-ture as does the front surface of the lens and which has a recessed portion, so that two different thick-nesses of film can be deposited on the lens. A small amount of a liquid plastic material is deposited in 15 the bifocal mold held concave surface-up. The lens is then placed in the mold, thereby spreading the liquid so it completely fills the space between the lens and the mold.
A suitable support is preferably used to hold 20 the lens a few thousandths of an inch above -the mold, to hold the astigmatic correction at its proper angle, and to provide the proper decentration of the bifocal portion. The combined assembly is then run through a curing cycle in an oven. After curing, ~he assembly 25 is allowed to cool. By inserting a razor at the edge ~;
of the point of contact between the lens and the mold, the new compound lens will separate readily from the mold, the lens including therewithin the newly cast bifocal portion, which has the desired distance cor-rection, the astigmatic correction at the proper axis, decentration, and the reading correction, all in the 5 proper location.
The present invention also performs all of the functions of the presently used gasket. It orients the convex lens surface and the concave mold surface so that they remain one directly over the other and 10 so that they remain parallel; it maintains a separa-tion between the mold and the lens; it retains the plastic liquid in the mold; and it allows shrinkage to occur.
Brief Description of the Drawings 15 The foregoing and other objects, features and advantages of the present invention will become more apparent to those skilled in the art from a reading of the detailed description hereinafter, when con-sidered in conjunction with the accompanying drawings, 20 wherein FIG. 1 is a perspective view of a first embodiment, in exploded relationship, of a new assem-bly for forming of lenses comprised of a holder having cooperating upper and lower molds; 25 p~
FIG. 2 is a slightly enlarged sectional view of the initially assembled holder having the lower mold positioned thereon and showing also the deposit of the liquid plastic material;
FIG. 3 is a sectional view similar to FIG. 2 5 ~ ;
having the upper mold positioned thereon;
FIG. 4 is a top plan view of a lens formed with the apparatus illustrated in FIGS. 1 through 3;
FIG. 5 is a top plan view of a holder illustra~ing another embodiment of the present 10 invention in the manufacture of a bifocal lens;
FIG. 6 is a second view similar to FIG. 2 showing the formation of a bifocal lens with the deposit of the liquid plastic material for bonding to a previously formed lens; 15 FIG. 7 is a fragmentary sectional view including the positioning of the lens on the holder and the movement of the liquid thereupon; ~ :
FIG. 8 is a fragmentary sectional view of the : 20 completed bifocal lens; 20 Fig. 9 is a top plan view of a bifocal lens ~ ::
- formed with the apparatus illustrated in FIGS. 5 ;
through 7; ~:
FIG. 10 is a view similar to FIG. 7 illustrating a modified step in the process; 25 ':
_ 9 _ . ~:
FIG 11 illustrates another embodiment of the present invention and is a view similar to FIG. 6 except that the complete bifocal lens is fabricated without the use of a previously formed lens; and FIG. 12 is a view similar to FIG. 3 illus- 5 trating the formed lens therein.
_etailed Description of the Preferred Embodiment :
Referring now ~o the drawings and, more particularly, to FIGS. 1 through 4, there is shown a first embodiment of an apparatus 10 ~or the 10 manufactur.ing of a lens 12 that is ~ormed having a pair of oppositely disposed spaced apart surfaces 14 and 16. Sur~ace 14 being the one having the convex ; .
spherical curvature, and the surface 16 having the inner concave cylindrical curvature. The surfaces 15 14 and 16 are connected by an outer end 18 extending therebetween and terminate in an outer edge 20, which as illustrated in FIG. 4, may have a clrcular con- :
figuration.
The lens 12 is for~ed having an astigmatic axis 20 22 illustrated by the b,roken lines in FIG. 4. To manufacture lens 12, there is provided a holder 24 which is utilized in conjunction with a lower or bottom .
mold 26 and a upper or top mold 28. The configuration of the molds 26 and 28 is such that lenses 12 can be 25 :
cast with constant front curvatures over an extended ' range of foci and astigmatic corrections. These lenses 12 may be made of glass, plastic or any other suitable material known in the art.
The mo'lds 26 and 28 are preferably made of 5 either glass or of electro-formed metal. The lower mold 26 includes an outer surface 30, which may be convex and an inner surface 32 which may be concave, ~ -with an intermediate or end wall 34 joining together the oppositely disposed surfaces 30 and 32. 10 '~
, The end wa'll 34 prefera'bly has a circular ;~
configuration which may substantially coincide with '-`
the outer edge 20 formed on lens 12. The upper mold . ~ i .. .
28 includes an outer surface 36 which may have a con~
cave configuration. An intermediate or end wall 40 15 '~
joins together the oppositely disposed surfaces 36 and 38. The end wall 40 preferably has a circular configuration, which as illustrated in FIG. 3, may '~
:
exceed the diameter de~ined by the outer edge 20.
To permit the manufacture of the lens 12, having 20 various selected angles of curvature, depending upon the configurations of molds 26 and 28 that are selec-ted, -the apparatus consisting of the holder 24 is utilized. The holder 24 includes a base portion 42 which has a bottom surface 44 on which ~he holder 2425 may be supported during use thereof. Base portion 42 ~, has an outer circumferentially extending side wall 46 , `- ~
which may have a circular or other configuration. An upper surface 48 extends in substantially parallel spaced rel.ationship to the bottom surace 44 and there may be provided a recess or through bore 50 extending intermediate the surfaces 44 and 48. 5 Support means 52 is operatively associated with the base portion 42 of the holder 24 so as to maintain the molds 26 and 28 in removably supportive vertically spaced position relative to each other, such that the lens 12 is formed intermediate the over- 10 lapping opposing surfaces 32 and 36 of the molds 26 and 28, respectively. The holder 24 may be fabricated from any suitable material; e.g., any metal capable of withstanding the temperatures to which the molds 26 and 28 are to be subjected. 15 ~
The support means 52 rnay be formed from a .
plurality of support posts 54 tha~ may be integrally foxmed with and extend upwardly from the upper surface 48 o~ the base portion 44. Each support post 54 may be ~ .
defined by a front surface 56 and a rear surface 58 20 that extend in spaced relationship to eac'n other.
Each post 54 may be dimensioned such that the rear sur-face 58 coincides with the side wall 46 of base portion 42 and terminates in a top or distal end 60.
Yhe support posts 54 may be circumferentially 25 and substantially equally spaced from each other. The support means 50 further comprises a lower step 62 provided in each of the support posts 54 for use in conjunction with the lower mold 26. An upper step 64 is similarly provided in each of the support posts 54 and similarly faces inwardly so as to be capable of removably supporting the upper mold 28 in the position 5 illustrated in FI&. 3. The steps 62 and 64 being in :~
substantially parallel relationship to each other so ~:
as to obtain a controlled thickness of the lens 12 to : ~ ~
be formed intermediate the overlapping molds 26 and 28. ~- :
To maintain the molds in proper position 10 . ~ .
relative ~o each other during the formation of lens 12, there is provided a vertically extending shouldPr 66 extending intermediate the lower step 62 and upper step 64, on each of the support posts 54. To prevent inadver~ent movement of upper mold 28, there is pro- 15 vided a substantially vertically extending shoulder `~
68 extending between upper step 64 and distal end:60. .
Shoulder 66 is appropriately dimensioned to `~
confine the end wall 34 of lower mold 26. Shoulder 68 ; .:
is appropriately dimensioned to confine the end wall 20 40 of upper mold 28. As illustrated in FIGS. 2 and 3, the shoulder 68 extends outwardly beyond shoulder 66 :~
to accommodate the molds 26 and 28 having differing outer diameters. Each of the steps 62 and 64 is down~
wardly and lnwardly inclined to subs~antially conform 25 :
to the angular configuration of the molds 26 and 28.
In this manner, the holder 24 is capable of being utilized to form lenses having various partic-ular configurations. The process by ~hich a partic-ular lens 12 is manufactured is that a previously selected lower mold 26 is positioned on the support 5 posts 54 and retained in place by the lower steps 62.
Once this is accomplished ~here is a filling of the lower mold 26 with a resin material 70. In its liquid form the resin material 70, as illustrated in FIG. 2, is now ready to be initially formed. The initial 10 ~ -formation of the lens 12 takes place by positioning the upper mold 28 in vertically spaced relationship to the lower mold 26. This is accomplished since the upper steps 64 are dimensioned to readily receive the upper mold 26 thereon, whereby the resin material 70 15 is displaced to extend between the overlapping sur-faces 32 and 36 of the molds 26 and 28, respectively, to form the configuration of the lens 12. ;
In the assembled position of the molds 26 and 28, as illustrated in FIG. 3, there may occur a curing 20 of the resin material 70 which may take place in an oven 72, illustrated in phantom, and a subsequent cooling of the resin material 70 to a temperature at which a separating of the lens 12 from between the molds 26 and 28 may take place. 25 ., :
A second embodiment of the present invention, and, in par~icular, of the formation of a lens having a bifocular portion or segment, is illustrated in , ~ :
FIGS. 5 through 10, wherein similar parts are denoted ~ ~
by similar reference numerals. 5 -~ -In this embodiment, a previously fabrica~ed lens 12A, which might have been manufactured in ~ ~
accordance with the embodiment illustrated in FIGS. 1 ~ ~:
through 4, is now utilized to produce a bifocal lens 74A, as illustrated in FIG. 8. In effect, lens 12A 10 :
forms the upper mold previously described with respect ~ ~
to FIGS. 1 through 4. ~The holder 24A is similarly ~:
utilized in that the lower mold 26A is supported by posts 54A and further includes a bifocal welI area or ~ .
por~ion 76A. The bifocal well area 76A, by its config 15 ;~
uration and orientation relative to the astigmatic -,~.
axis 22A, will determine~particular characteristics of the bifocal lens 74A. The bifocal ~lens 74A lS com-prised of lens 12A and a bifocular portion or segment 78A that is formed in the well 76A and further includes 20 a thin layer 80A which extends over the outer spherical conve~ curved surface 14A of lens 12A. The thin:layer 80A terminates in an outer margin 82A, as illustrated : .
in FIG. 8.
. The method of manufacturing t'ne bifocal lens 74A 25 includes the placing of the bifocal mold 26A in :
supportive position within the holder 24A. The lens 12A may be a single focus lens. The bifocal mold 26A
rests atop the lower steps 62A with the concave sur- ~
face 32A facing upwards. The concavity of each mold -26A has formed therein a recess or curvature which dif-fers from that of the lens surface 14A, to receive 5 additional material to create the bifocal effect.
The next step is ~o locate and position the -"stock" lens 12A over the mold 26A, the convex front ~ -surface 14A of ~he lens 12A being directed against the concave surface 32A of mold 26A. The lens 12A being 10 supported by the upper seats or steps 64A of the sup-port posts 54A. The upper steps 64A are so positioned with respect to the lip of the mold as to provide a narrow space between lens 12A and mold~surface 32A.
Care must be exercised in this step to avoid trapping 15 .
air bubbles between the liquid and the lens 12A, or in the liquid 70A. T~ere should be used a sufficient amount of the resin 70A that the placing of the lens 12A ~
causes the resin 70A to be spread evenly to form a thin layer of the resin between the mold 26A and the lens 12~. 20 Excess material, if any, can be scraped away ;~
: -using the marginal edge of the "stock" lens 12A as a guide, or ground away. When the resin is flooded into mold 26A, the spacing between the lens 12A and mold 26A
is a matter of a few thousandths of an inch. However, 25 at the recessed portion 76A in the concave face 32A of the mold 26A, there will be a thicker mass with a '',:'' '' - 16 - ~
2~
:, :
different curvature, to thereby provide the bifocal effect desired. The importance of the horizontal portions of the upper steps 6~ being parallel can now be appreciated. It allows the lens 12A and mold 26A to rest parallel to each other and prevents the 5 resultant bifocal lens 74A from having a cast-in prism. ;
Thereafter, a predetermined amount of a -castable resin, as at 70A, is placed onto the concave portion 32A. The amount of resin used is dependent 10 upon the desired diameter and thickness of the bifocal lens 74A sought to be obtained. Usually, about 4 to ;~
6 cc. of the resin will be the appropriate amount.
The preferred resin is CR 39 plastic, but tests using ` ~ ` j :
a 100% solution of CR 39 indicate~that the boiling 15 characteristics of such a bifocal lens are not adequate.
Therefore, it was found necessary to introduce quanti-ties~of methyl methacrylate or ethyl methacrylate to the CR 39 in order to improve the boiling character~
istics. 20 These results were obtained by numerous laboratory tests, and a~e shown in Table I. The tests were made under three types of boil.ing conditions:
one and a half hours of continuous boiling; two hours ;
of continuous boiling; and two hours of intermittent 25 boiling. (Since plastic lenses are tinted in boillng water solutions of dyes, boiling was used as the basis ~ 17 2~
for the tests.) The major causes of lens failure were: -crazing resulting from insufficient cure of the applied portion of the bifocal; delamination caused by -insufficient adhesion between the applied portion and `
the original base lens; and splits caused by an uneven 5 ~ .
expansion of the applied portion and of the original :
base lens.
The materials to form the lens of the embodi- `
ment illustrated in FIGS. 5 through 10 may also be .
utilized to form the lens previously illustrated with 10 respect to the embodiment in FIGS. 1 through 4, as well as the embodiment hereinafter discussed with respect to FIGS. 11 and 12. ~ .
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~ ~ a v 1, _ 1q In order to provide for individualized astig-matic correction, as illustrated in FIG. 5, there is provided indicia means 84A operatively associated with the holder 24A so as to permit prescribed angular orientation of either the mold 26A or the lens 12A 5 ;
relative to each other so as to obtain a resultant bifocal lens 74A with a prescribed astigmatic axis 22A
relative to the bifocular portion 78A. By providing this capability, it is possible to customize the desired bifocal lens 74A since the lens 12A can be appropriately 10 turned so that the resin 70A will accumulate at the individual point or area desired.
The indicia means 84A may be provided on the -~
base upper surface 48A and include a plurality of cir-cumferentially disposed markings 86A. As indicated, 15 ~ ~-the reference orientation of 0~; 90; 180; and;270 This permits the aligning of the astigmatic axis 22A of the lens 12A relative to the recessed well portion 76A
in a predetermined orientation. In this matter, the bifocular portion 78A is formed on the lens 12A in~a 20 desired position dependent upon the prescribed needs of the prospective user thereof. By indicating visually the positionable angular degree of orîentation by the indicia means 84A, the desired adjusting may take place. :~
With particular reference to FIG. 10, shim 25 :~
means 88A may be utilized in the form of a wedge element 90A which is placed around one of the upper .
. .
support steps 64A to achieve a desired degree of decentration of the optical center with respect to the bifocal segment 78A, and to achieve ~his decentration for any angle required in any prescription. The wedge element 90A may be used on either one, two or possibly 5 three of the four support steps 64A.
The entire assembly is now placed in an air circulating oven 72A for curing. Since CR 39 cures slowly at low temperatures and quickly at high temper-atures, a variety of curing cycles are available. For 10 instance, sixteen hours at 57C(135F) and then forty ~
minutes at 82C(180F) gives a well cured bifocal lens ~ ~ ;
74A. However, it is desirable to turn over the expen-sive molds as many times as possible consistent with ;~
quality production; therefore, shorter cycles have been 15 used and have provided lenses with excellent results and full cure. Two acceptable shorter cycles are: thirty minutes at 71C(160F), thirty minutes at 77C(170F), and thirty minutes at 82C(180F) and twenty minutes at 77~C(170F), twenty minutes at 82C(180F) and twenty 20 minutes a~ 88C(190F).
After curing, the assembly is allowed to cool to about 60C(140F), and the lens 74A is then separated fom the mold 26A, the newly cast bifocal film portion 80A is integral with the original lens 12A. The resultant lens 25 74A, after edge grinding for peripheral shaping is now a complete bifocal lens, including distance correction, astigmatic correction at the proper axis, and the reading correction at the proper location, the lens also being properly decentered according to the individual prescription. One of the ways to separate the lens and the mold is to permit the assembly to cool to room temperature, and the lens 74A will separate spon-taneous- 5 ~-ly from mold 26A. Another and faster way is to insert a razor blade just at the edge of the point of contact :
between the lens 74A and mold 26A. Accordingly, the ~-finished bifocal lens 74A illustrated in FIG. 9 has the bifocular portion 78A contained onthe convex surface of 10 ~: :
the lens 74A, as illustrated in FIG. 8. The bifocular portion 78A may include a horizontally extending ledge 92A. ~ -A final embodiment of an apparatus 10B for the manufacture of a bifocal lens 76B is depicte~ in FIGS. 15 11 and 12 wherein similar parts are denoted by similar reference m ~erals. In this embodiment, the lens 76B
is formed with the bifocular portion 78B integrally formed thereon at the time of formation of the retaining :~
portion of the lens 76B. 20 The steps to fabricate the lens 76B are similar to that discussed with respect to those illustrated in FIGS. 1 through 5. Further, the holder 24B may have ~ :
thereon the indicia means illustrated in FIG. 5. In this manner, the final lens 74B is formed with a bifo- 25 cular portion 78B by having the lower mold 26B provided :
wi~h a well area 76B. The process by which a particular lens 74B is manufactured is that a previoulsy selected lower mold 26B is positioned on the support posts 54B
and retained in place by the lower steps 62B. Once this is accomp]ished there is a filling of the lower mo].d with a resin material 70B. In its liquid form 5 the resin material 70B, as illustrated in E'IG. 11, is now ready to be formed. The formation of the lens 74B
takes place by positioning the upper mold 28B in vertically spaced relationship to the lower mold 26B.
This is accomplished since the upper steps 64B are 10 dimensioned to readily receive the upper mold 26B
thereon, whereby the resin material 70B is displaced to extend between the overlapping surfaces 32B and 36B :
of the molds 26B and 28B, respectively, to form the configuration of the lens 74B irlcluding the bifocular 15 portion 78B.
In the assembled position of the molds 26B :~
and 2~B, as illustrated in FIG. 12, there is a curing of the resin m~terial 70B which may take place in an oven 72B, illustrated in phantom, and a subsequent 20 cooling of the resin material 70B to a temperature at ; ~`
which a separating of the lens 74B from between the molds 26B and 28B may -take place.
Accordingly, the embodiment of the invention illustrated in FIGS. 11 and 12 may be utilized with the 25 apparatus illustrated in FIGS. 5 and 10, thereby per-mitting orientation of the bifocular portion 78B, which may be of any predetermined geometric configuration and decentration accomplished by placing wedges on steps 64B. In this manner the pupillary distance may be varied either inwardly or outwardly, upwardly or downwardly.
S Attention is directed to the fact that the steps 5 62 and 64, in all embodiments, have been described as being disposed in respective parallel disposition; how- ~-ever, when a mold is employed which has a convex cylindrical curve 'to provide for astigmatic correction), -one pair of diametrically opposed steps 62 or 64 will lO
be disposed in a plar.e parallel to, but vertically dis-posed from the plane defined by the other pair of diametrically opposed s~eps 62 or 64. The foregoing may be accomplished by constructing the holder 24 in accordance with the above teachings. Alternatively, the 15 holder may have the construc~ion discussed previously and the steps may be modified to accomodate the convex cylindrical curve of the mold by the utilization of shim means, similar to shim means 88A, in FIG. lO. ~ ~;
The present invention permits the casting of 20 major corrections on the inner surface, and the outer -surface curvature is substantially standardized. There-fore, the number of molds required by a laboratory w111 be determined solely by the various number of diopter corrections required for the bifocular portion of the 25 completed lens structure, which is approximately 50-75 ~` :
different molds. Of course, special requirements and - 2~
conditions may arise increasing the required number of molds for a laboratory. However, if the castings were made pursuant to present state of the art methods, the -number of molds required would be astronomical. This is because the present day method is to keep the inner 5 surface constant and cast prescriptions on the outer surface.
It will thus be apparent that the present ~' invention provides a new and novel apparatus for fabricating plastic lens blanks and bifocal plastic 10 lens blanks which do not require any grinding of the astigmatic curve by an ophthamological laboratory.
Moreover, the present invention deletes the necessity of utilizing compressive gaskets placed upon upper and lower molds in the formation of said lens blanks. In 15 this regard, attention is directed to the fact that the utilization of the gaskets is quite expensive since they may only be used once and must thereafter be discarded and replaced by a new gasket when utilizing the molds to form additional lens blanks. 20 It will be apparent to those skilled in the art that the teachings of the present invention are primarily intended for use by an ophthamological laboratory. However, it is within the realm and teachings of the present invention to enable an optician 25 to fabricate the lenses within his business establish-ment, should he wish to provide the required initial investment for the method and apparatus of the present invention. :
However, the most important advantage obtained :~
by the use of the present invention is that both ophthalmic lenses and bifocal ophthalmic lenses may be 5 cast in accordance with an ophthamologist's prescrip-tion and without necessitating any grinding of the lenses to orient the astigmatic axis of said lenses to the prescribed angular orientation.
While I have shown and described the various 10 preferred embodiments of the present invention, it will be appreciated that the teachings herein will readily lend itself to many modifications, changes, combinations, and improvements by those s:killed in the art, without deviating from the present invention or the teachings 15 :
hereof.
:: :
Claims (55)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of producing an ophthalmic toric lens without utilization of a gasket and comprising the steps of supporting a lower mold in a predetermined and selected orientation, filling said lower mold with a resin material, positioning an upper mold in vertically spaced and non-compressive relationship to said lower mold, whereby said resin material is displaced to extend bet-ween the overlapping surfaces of said molds to form the configuration of said lens, curing said resin material situated between said molds, cooling said resin material and said molds, whereby said lower mold is capable of movement to com-pensate for shrinkage of said resin material and seperat-ing said lens from between said molds.
2. The method in accordance with claim 1, wherein said curing step consists of curing in an air circulating oven for sixteen hours at 135°F and for forty minutes at 180°F.
3. The method in accordance with claim 1, wherein said curing step consists of curing in an air circulating oven for thirty minutes at 160°F, for thirty minutes at 170°F, and for thirty minutes at 180°F.
4. The method in accordance with claim 1, wherein said curing step consists of curing in an air circulating oven for twenty minutes at 170°F, for twenty minutes at 180°F and for twenty minutes at 190°F.
5. The method in accordance with claim 1, wherein said resin material and said molds are cooled to approx-imately 140°F.
6. The method in accordance with claim 1, including the step of separating said molds and said lens by inserting a sharpened edge member just at the edge of the point of contact between said lens blank and one of said molds.
7. The method in accordance with claim 1, including the step of casting a bifocal segment onto said lens without changing the curvature or power thereof, except at the bifocal segment.
8. The method in accordance with claim 7, wherein said casting of said bifocal segment occurs subsequent to the forming of said lens.
9. The method in accordance with claim 1, wherein said resin is an allyl diglycol carbonate plastic.
10. The method in accordance with claim 1, wherein said resin is a solution of an allyl diglycol carbonate plastic and methyl methacrylate.
11. The method in accordance with claim 1, wherein said resin is a solution of an allyl diglycol carbonate plastic and ethyl methacrylate.
12. The method in accordance with claim 1, including prior to curing the step of adjusting the vertical spacing between said overlapping surfaces of said molds whereby the center of curvature of the interior surface of said lens is selec-tively varied.
13. The method in accordance with claim 1, including the step of providing a holder capable of supporting said lower mold thereon and simultaneously positioning said upper mold in said vertically spaced relationship to said lower mold.
14. A method of producing an ophthalmic toric bi-focal lens comprising the steps of supporting a bifocal mold having a recessed bifocal well area portion on this concave surface, filling said bifocal mold with a resin material, positioning the convex front surface of a single focus lens having an astigmatic axis in overlapping and selectively spaced relationship with respect to said con-cave surface of said bifocal mold whereby said resin con-tained in said recessed portion is in contact with said convex front surface of said lens for subsequent formation of a thin plastic film from said resin, curing the assembly of said resin material and said lens, cooling said mold and said resin material which has formed said thin plastic film, whereby said lower mold is capable of movement to compensate for shrinkage of said resin material, separating said lens from said mold, and said thin plastic film on said lens having one portion corresponding to the recess in said mold being thicker than the rest thereof, thereby creating a bi-focular portion.
15. The method in accordance with claim 14, includ-ing prior to curing the step of aligning said astigmatic axis of said lens rel-ative to said recessed portion in a predetermined orienta-tion, whereby said bifocular portion is formed on said lens in a desired position dependent upon the prescribed needs of the prospective user thereof.
16. The method in accordance with claim 15, includ-ing the step of indicating visually the positionable angular degree of orientation of said lens relative to said mold so as to form said bifocular portion in prescribed pos-itional orientation on said lens relative to said astig-matic axis.
17. The method in accordance with claim 14, including the step of adjusting the vertical spacing between said con-cave surface of said mold and said convex front surface of said lens.
18. The method in accordance with claim 14, including the step of separating said molds and said lens blank by inserting a blade just at the edge of the point of con-tact between said lens blank and one of said molds.
19. The method in accordance with claim 14, wherein said resin is an allyl diglycol carbonate plastic.
20. The method in accordance with claim 19, wherein said resin is a solution of an allyl diglycol carbonate plastic and methyl methacylate.
21. The method in accordance with claim 14, wherein said resin is a solution of an allyl diglycol carbonate plastic and ethyl methacrylate.
22. The method in accordance with claim 14, wherein said resin material and said mold are cooled to approx-imately 140°F.
23. The method in accordance with claim 14, includ-ing the step of providing a holder capable of supporting said bifocal mold thereon and capable of permitting the posi-tioning of said lens in said vertically spaced relation-ship to said bifocal mold.
24. A method of producing an ophthalmic toric bi-focal lens comprising the steps of supporting a bifocal lower mold having a re-cessed bifocal well area on its concave surface, filling said lower mold with a resin material, positioning an upper mold in vertically and selectively spaced relationship to said lower mold, whereby said resin material is displaced to extend bet-ween the overlapping surfaces of said molds to form the configuration of said bifocal lens with a bifocular por-tion on the convex lens surface corresponding to said bifocal well on said lower mold, curing said resin mater-ial situated between said molds, cooling said resin material and said molds, whereby said lower mold is capable of movement to com-pensate for shrinkage of said resin material, and sep-arating said bifocal lens from between said molds.
25. The method in accordance with claim 24, includ-ing the step of indicating visually the positionable angular degree of orientation of said bifocular portion relative to the astigmatic axis being formed on said bifocal lens in prescribed position relative to said astigmatic axis.
26. The method in accordance with claim 25, includ-ing the step of aligning said astigmatic axis of said upper mold relative to said recessed well in a predetermined orientation, whereby said bifocular portion is formed on said bifocal lens in a desired position dependent upon the prescribed needs of the prospective user thereof.
27. The method in accordance with claim 26, includ-ing the step of providing a holder capable of supporting said lower mold thereon and capable of permitting the posi-tioning of said upper mold in said vertically and selec-tively spaced relationship to said lower mold.
28. The method in accordance with claim 27, includ-ing the step of applying upon said holder indicia capable of providing for said angular degree of orientation between said molds.
29. The method in accordance with claim 24, includ-ing prior to curing the step of adjusting the vertical spacing between said concave surface of said lower mold and said convex front surface of said upper mold, whereby the centre of curva-ture of the concave rear surface of said bifocal lens is altered.
30. The method in accordance with claim 24, wherein said curing step consists of curing in an air circulating oven for sixteen hours at 135°F and for forty minutes at 180°F.
31. The method in accordance with claim 24, wherein said curing step consists of curing in an air circulating oven for thirty minutes at 160°F for thirty minutes at 170°F, and for thirty minutes at 180°F.
32. The method in accordance with claim 24, wherein said bifocular portion is formed simultaneously with the formation of the remainder of said bifocal lens.
33. The method in accordance with claim 24, wherein said resin is an allyl diglycol carbonate plastic.
34. The method in accordance with claim 24, wherein said resin is a solution of an allyl diglycol carbonate plastic and methyl methacrylate.
35. The method in accordance with claim 24, wherein said resin is a solution of an allyl diglycol carbonate plastic and ethyl methacrylate.
36. The method in accordance with claim 24, includ-ing the step of separating said molds and said bifocal lens by inserting a sharpened edge member just at the edge of the point of contact between said bifocal lens and one of said molds.
37. The method in accordance with claim 24, wherein said curing step consists of curing in an air circulating oven for twenty minutes at 170°F, for twenty minutes at 180°F, and for twenty minutes at 190°F.
38. The method in accordance with claim 24, wherein said resin material and said mold are cooled to approx-imately 140°F.
39. Apparatus for fabricating a lens utilizing an upper mold and a lower mold comprising in combination a holder including a base portion, and support means operatively associated with said base portion so as to maintain said molds in removably supportive vertically spaced position relative to each other such that a lens is formed intermediate the overlapping opposing surfaces of said mold, said support means comprising a lower step for said lower mold and an upper step for said upper mold, said steps being disposed in substantially parallel relationship to each other so as to obtain a controlled thickness to said lens, and each of said steps being provided with a vertically extending shoulder for confining the molds on each of said steps and for abbuttingly engaging a peripheral portion of the respective ones of said molds, thereby maintaining said molds in predetermined fixedly spaced relationship with respect to one another.
40. Apparatus in accordance with Claim 39, wherein each of said steps are downwardly and inwardly inclined with respect to said base portion to substantially conform to the angular configuration of said molds.
41. Apparatus in accordance with Claim 40, wherein said steps are circumferentially and substantially equidistantly spaced from one anther.
42. Apparatus in accordance with Claim 41, wherein said upper steps extend outwardly beyond said inner steps so as to be capable of supporting said molds having differing outer diameters.
43. Apparatus in accordance with Claim 39, wherein said support means comprises a plurality of support posts extending upwardly from said base portion and having said steps formed thereon.
44. Apparatus in accordance with Claim 43, wherein said support posts are circumferentially and substantially equidistantly spaced from one anther.
45. Apparatus in accordance with Claim 39, including indicia means operatively associated with said holder so as to permit prescribed angular orientation of either one of said molds relative to a prescribed astigmatic axis.
46. Apparatus in accordance with Claim 45, wherein said indicia means is provided on said base portion and includes a plurality of circumferentially disposed and preselectedly spaced markings.
47. Apparatus in accordance with Claim 46, wherein said markings circumscribe 360 degrees.
48. Apparatus in accordance with Claim 46, wherein said lower mold is provided with a bifocal well area so as to cast a bifocal segment on the lens formed with the apparatus.
49. Apparatus in accordance with Claim 48, wherein said upper mold is in the form of a previously formed lens so as to integrally cast said bifocal segment onto the outer surface of said lens.
50. Apparatus in accordance with Claim 39, including shim means adapted to be positioned relative to said support means for decentration of the lens to be formed.
51. Apparatus as claimed in claim 39 for fabricating a bifocal lens, wherein said upper mould is a pre-formed lens having a spherical outer curve and wherein said lower mould has a bifocal well area for casting a bifocal segment on the spherical outer curve of said pre-formed lens, and wherein said support means is operatively associated with said base portion of the holder to maintain said lower mould and said lens in removably supportive and vertically spaced position relative to one another, said bifocal lens segment being capable of formation on said outer spherical curve of said lens in dependence upon the overlapping opposing surfaces of said mould and said lens being maintained in position by said support means.
52. Apparatus in accordance with claim 51, wherein each of the steps of said support means is downwardly and inwardly inclined with respect to said base portion in order to substantially conform to the angular configuration of said mould and said lens, said steps being circumferentially and substantially equidistantly spaced from one another, and said upper steps extend outwardly beyond said inner steps so as to be capable of supporting said mould and said lens having differing outer diameters.
53. Apparatus in accordance with claim 51, wherein said support means comprises a plurality of support posts extending upwardly from said base portion and having said steps formed thereon, and said support posts are circum-ferentially and substantially equidistantly spaced from one another.
54. Apparatus in accordance with claim 51, including indicia means operatively associated with said holder so as to permit prescribed angular orientation of either said mould or said lens relative to one another so as to obtain a lens with a prescribed astigmatic axis.
55. Apparatus in accordance with claim 54, wherein said indicia means is provided on said base portion and includes a plurality of pre-selectedly spaced circumferentially disposed markings.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US77612977A | 1977-03-10 | 1977-03-10 | |
| US776,129 | 1977-03-10 | ||
| US05/810,357 US4190621A (en) | 1977-03-10 | 1977-06-27 | Method for molding optical plastic lenses of the standard and bifocal type |
| US810,357 | 1977-06-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1098268A true CA1098268A (en) | 1981-03-31 |
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ID=27119152
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA296,512A Expired CA1098268A (en) | 1977-03-10 | 1978-02-09 | Method and apparatus for molding optical plastic lenses of the standard and bifocal type |
Country Status (18)
| Country | Link |
|---|---|
| US (1) | US4190621A (en) |
| JP (1) | JPS53124570A (en) |
| BE (1) | BE864672A (en) |
| CA (1) | CA1098268A (en) |
| CH (1) | CH625458A5 (en) |
| DE (1) | DE2809610A1 (en) |
| DK (1) | DK105278A (en) |
| ES (2) | ES467649A1 (en) |
| FI (1) | FI780749A (en) |
| FR (1) | FR2383002A1 (en) |
| GB (1) | GB1601327A (en) |
| IE (1) | IE46344B1 (en) |
| IL (1) | IL54079A (en) |
| IT (1) | IT1108328B (en) |
| NL (1) | NL7802485A (en) |
| NO (1) | NO780731L (en) |
| PT (1) | PT67745A (en) |
| SE (1) | SE7802719L (en) |
Families Citing this family (109)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4364878A (en) * | 1978-08-10 | 1982-12-21 | Omnitech Inc. | Method for molding ophthalmic lenses |
| GB2040785B (en) * | 1978-12-28 | 1983-01-26 | Philips Electronic Associated | Producing polymer glass asherical optical elements |
| US4522768A (en) * | 1979-05-11 | 1985-06-11 | Sola Products Limited | Casting gasket assembly and method for casting lenses therefrom |
| US4284399A (en) * | 1980-06-23 | 1981-08-18 | American Optical Corporation | Contact lens mold |
| US4637904A (en) * | 1983-11-14 | 1987-01-20 | Rohm And Haas Company | Process for molding a polymeric layer onto a substrate |
| US4605524A (en) * | 1984-11-19 | 1986-08-12 | Danker Laboratories, Inc. | Method and master-die for casting a bifocal contact lens in a single piece |
| FR2576820B1 (en) * | 1985-02-01 | 1989-04-07 | Essilor Int | SUPPORT RING FOR FIXING A MOUNTING BLOCK ON THE FINISHED SIDE WITH A PROGRESSIVELY VARIABLE CURVE OF A SEMI-FINISHED BLANK OF A PALLET, SUCH AS AN OPHTHALMIC LENS OR MOLD |
| US4693446A (en) * | 1985-09-20 | 1987-09-15 | Techna Vision, Inc. | Gasket for molding plastic lenses |
| JPS62295001A (en) * | 1986-06-14 | 1987-12-22 | Nippon Sheet Glass Co Ltd | Multi-focus spherical lens made of synthetic resin and its production |
| JPS63247014A (en) * | 1987-04-03 | 1988-10-13 | Takashi Mori | Manufacture of transparent capusle |
| BR8802923A (en) * | 1987-06-18 | 1989-01-03 | Ocular Technologies Inc | PROCESS FOR MANUFACTURING A CONTACT LENS, MATRIX FOR MANUFACTURING A CONTACT LENS AND FORM FOR MANUFACTURING A MATRIX |
| US5178800A (en) * | 1990-10-10 | 1993-01-12 | Innotech, Inc. | Method for forming plastic optical quality spectacle lenses |
| US5219497A (en) * | 1987-10-30 | 1993-06-15 | Innotech, Inc. | Method for manufacturing lenses using thin coatings |
| US5147585A (en) * | 1987-10-30 | 1992-09-15 | Blum Ronald D | Method for forming plastic optical quality spectacle lenses |
| FR2638391B1 (en) * | 1988-10-27 | 1991-01-25 | Essilor Int | PROCESS FOR FORMING AN OPHTHALMIC LENS FROM A PALLET OF SYNTHETIC MATERIAL |
| US5141678A (en) * | 1990-10-10 | 1992-08-25 | Blum Ronald D | Method for forming disposable molds for producing optical quality lenses |
| GB9125480D0 (en) * | 1991-11-29 | 1992-01-29 | Pilkington Visioncare Holdings | Polymeric bifocal lens production process |
| US5470892A (en) * | 1992-05-01 | 1995-11-28 | Innotech, Inc. | Polymerizable resin for forming clear, hard plastics |
| US5288221A (en) * | 1992-05-18 | 1994-02-22 | Essilor Of America, Inc. | Apparatus for making ophthalmic lenses |
| US5316702A (en) * | 1992-07-20 | 1994-05-31 | Innotech, Inc. | Method of producing durable bonds between an optical preform and an optical resin layer cast on the preform surface |
| US5480600A (en) * | 1993-03-24 | 1996-01-02 | Innotech, Inc. | Method for manufacturing thin progressive addition lenses |
| JPH09506560A (en) * | 1993-12-10 | 1997-06-30 | イノテック・インコーポレーテッド | Method and apparatus for manufacturing photochromic lens |
| US5531940A (en) * | 1993-12-10 | 1996-07-02 | Innotech, Inc. | Method for manufacturing photochromic lenses |
| JPH08216271A (en) * | 1995-02-10 | 1996-08-27 | Kureha Chem Ind Co Ltd | Manufacture of synthetic resin dimming lens |
| US5789015A (en) * | 1996-06-26 | 1998-08-04 | Innotech, Inc. | Impregnation of plastic substrates with photochromic additives |
| US5793465A (en) * | 1996-10-08 | 1998-08-11 | Innotech, Inc. | Toric surfacecasting |
| US5914174A (en) * | 1996-12-05 | 1999-06-22 | Innotech, Inc. | Lens or semi-finished blank comprising photochromic resin compositions |
| JP3710260B2 (en) * | 1997-06-23 | 2005-10-26 | キヤノン株式会社 | Optical element, holding jig for holding the same, and imaging apparatus using the optical element |
| US5989462A (en) | 1997-07-31 | 1999-11-23 | Q2100, Inc. | Method and composition for producing ultraviolent blocking lenses |
| AR013512A1 (en) | 1997-09-24 | 2000-12-27 | Novartis Ag | METHOD TO MANUFACTURE AN ASTIGMATIC CONTACT LENS |
| WO2000005060A1 (en) * | 1998-07-24 | 2000-02-03 | Optical Molding Systems, Inc. | Method and compositions for manufacturing coated photochromatic articles |
| US6936197B1 (en) | 1998-07-24 | 2005-08-30 | Duane L. Wires | Method and compositions for manufacturing coated photochromatic articles |
| US6478990B1 (en) * | 1998-09-25 | 2002-11-12 | Q2100, Inc. | Plastic lens systems and methods |
| US6419873B1 (en) * | 1999-03-19 | 2002-07-16 | Q2100, Inc. | Plastic lens systems, compositions, and methods |
| FR2793038B1 (en) | 1999-04-29 | 2002-01-25 | Essilor Int | COMPOSITE OPHTHALMIC LENS AND METHOD FOR OBTAINING SUCH A LENS |
| US7023594B2 (en) * | 2000-06-23 | 2006-04-04 | E-Vision, Llc | Electro-optic lens with integrated components |
| US6619799B1 (en) | 1999-07-02 | 2003-09-16 | E-Vision, Llc | Optical lens system with electro-active lens having alterably different focal lengths |
| US7775660B2 (en) | 1999-07-02 | 2010-08-17 | E-Vision Llc | Electro-active ophthalmic lens having an optical power blending region |
| US6698708B1 (en) | 2000-03-30 | 2004-03-02 | Q2100, Inc. | Gasket and mold assembly for producing plastic lenses |
| US6723260B1 (en) | 2000-03-30 | 2004-04-20 | Q2100, Inc. | Method for marking a plastic eyeglass lens using a mold assembly holder |
| US6960312B2 (en) * | 2000-03-30 | 2005-11-01 | Q2100, Inc. | Methods for the production of plastic lenses |
| US6609793B2 (en) * | 2000-05-23 | 2003-08-26 | Pharmacia Groningen Bv | Methods of obtaining ophthalmic lenses providing the eye with reduced aberrations |
| US8020995B2 (en) | 2001-05-23 | 2011-09-20 | Amo Groningen Bv | Methods of obtaining ophthalmic lenses providing the eye with reduced aberrations |
| AUPR276601A0 (en) * | 2001-01-31 | 2001-02-22 | Newman, Steve | A contact lens for refractive correction and capable of engagement with an eye either inside out or right way out |
| US7004740B2 (en) * | 2001-02-20 | 2006-02-28 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a heating system |
| US6752613B2 (en) | 2001-02-20 | 2004-06-22 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a controller for initiation of lens curing |
| US6840752B2 (en) | 2001-02-20 | 2005-01-11 | Q2100, Inc. | Apparatus for preparing multiple eyeglass lenses |
| US6726463B2 (en) | 2001-02-20 | 2004-04-27 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a dual computer system controller |
| US7011773B2 (en) * | 2001-02-20 | 2006-03-14 | Q2100, Inc. | Graphical interface to display mold assembly position in a lens forming apparatus |
| US6676399B1 (en) | 2001-02-20 | 2004-01-13 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having sensors for tracking mold assemblies |
| US6875005B2 (en) | 2001-02-20 | 2005-04-05 | Q1200, Inc. | Apparatus for preparing an eyeglass lens having a gating device |
| US7052262B2 (en) * | 2001-02-20 | 2006-05-30 | Q2100, Inc. | System for preparing eyeglasses lens with filling station |
| US7037449B2 (en) * | 2001-02-20 | 2006-05-02 | Q2100, Inc. | Method for automatically shutting down a lens forming apparatus |
| US6893245B2 (en) | 2001-02-20 | 2005-05-17 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a computer system controller |
| US6712331B2 (en) * | 2001-02-20 | 2004-03-30 | Q2100, Inc. | Holder for mold assemblies with indicia |
| US7045081B2 (en) * | 2001-02-20 | 2006-05-16 | Q2100, Inc. | Method of monitoring components of a lens forming apparatus |
| US6962669B2 (en) | 2001-02-20 | 2005-11-08 | Q2100, Inc. | Computerized controller for an eyeglass lens curing apparatus |
| US7060208B2 (en) * | 2001-02-20 | 2006-06-13 | Q2100, Inc. | Method of preparing an eyeglass lens with a controller |
| US6790022B1 (en) | 2001-02-20 | 2004-09-14 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a movable lamp mount |
| US7124995B2 (en) | 2001-02-20 | 2006-10-24 | Q2100, Inc. | Holder for mold assemblies and molds |
| US6612828B2 (en) * | 2001-02-20 | 2003-09-02 | Q2100, Inc. | Fill system with controller for monitoring use |
| US6702564B2 (en) * | 2001-02-20 | 2004-03-09 | Q2100, Inc. | System for preparing an eyeglass lens using colored mold holders |
| US6758663B2 (en) * | 2001-02-20 | 2004-07-06 | Q2100, Inc. | System for preparing eyeglass lenses with a high volume curing unit |
| US7051290B2 (en) | 2001-02-20 | 2006-05-23 | Q2100, Inc. | Graphical interface for receiving eyeglass prescription information |
| US6863518B2 (en) * | 2001-02-20 | 2005-03-08 | Q2100, Inc. | Mold filing apparatus having multiple fill stations |
| US6899831B1 (en) | 2001-02-20 | 2005-05-31 | Q2100, Inc. | Method of preparing an eyeglass lens by delayed entry of mold assemblies into a curing apparatus |
| US7025910B2 (en) * | 2001-02-20 | 2006-04-11 | Q2100, Inc | Method of entering prescription information |
| US6709257B2 (en) * | 2001-02-20 | 2004-03-23 | Q2100, Inc. | Eyeglass lens forming apparatus with sensor |
| US6676398B2 (en) | 2001-02-20 | 2004-01-13 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a prescription reader |
| US7083404B2 (en) | 2001-02-20 | 2006-08-01 | Q2100, Inc. | System for preparing an eyeglass lens using a mold holder |
| US7139636B2 (en) | 2001-02-20 | 2006-11-21 | Q2100, Inc. | System for preparing eyeglass lenses with bar code reader |
| US6655946B2 (en) | 2001-02-20 | 2003-12-02 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a controller for conveyor and curing units |
| US7074352B2 (en) * | 2001-02-20 | 2006-07-11 | Q2100, Inc. | Graphical interface for monitoring usage of components of a lens forming apparatus |
| US6790024B2 (en) * | 2001-02-20 | 2004-09-14 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having multiple conveyor systems |
| SE0101702D0 (en) * | 2001-05-15 | 2001-05-15 | Ardenia Investments Ltd | Novel potentiating compounds |
| US6488374B1 (en) | 2002-02-12 | 2002-12-03 | Davida Charlene Alberts | Eyeglasses and method of making same for the treatment of low-vision |
| US6872335B2 (en) * | 2002-03-12 | 2005-03-29 | Technology Resource International Corporation | Method and apparatus for holding a mold assembly and molding an optical lens using the same |
| US20080106633A1 (en) * | 2002-03-13 | 2008-05-08 | Blum Ronald D | Electro-optic lens with integrated components for varying refractive properties |
| US7044429B1 (en) | 2002-03-15 | 2006-05-16 | Q2100, Inc. | Methods and systems for coating eyeglass lens molds |
| FR2850319B1 (en) * | 2003-01-24 | 2005-03-04 | Essilor Int | METHOD FOR FILLING A MOLD WITH LIQUID ORGANIC MATERIAL FOR MOLDING AN OPTICAL MEMBER, AND MOLDING METHOD INCLUDING THE FILLING METHOD |
| FR2850443B1 (en) * | 2003-01-24 | 2005-03-04 | Essilor Int | POINTEAU VALVE FOR FILLING A MOLD WITH LIQUID ORGANIC MATERIAL AND METHOD FOR MOLDING AN OPTICAL MEMBER USING SUCH A VALVE |
| JPWO2004109369A1 (en) | 2003-06-09 | 2006-07-20 | 株式会社アサヒオプティカル | Bifocal plastic lens |
| FR2856005B1 (en) * | 2003-06-11 | 2007-03-23 | Essilor Int | METHOD AND DEVICE FOR MOLDING AN OPTICAL LENS, ESPECIALLY AN OPHTHALMIC LENS |
| US20060065989A1 (en) * | 2004-09-29 | 2006-03-30 | Thad Druffel | Lens forming systems and methods |
| US8915588B2 (en) | 2004-11-02 | 2014-12-23 | E-Vision Smart Optics, Inc. | Eyewear including a heads up display |
| US9801709B2 (en) | 2004-11-02 | 2017-10-31 | E-Vision Smart Optics, Inc. | Electro-active intraocular lenses |
| US8778022B2 (en) | 2004-11-02 | 2014-07-15 | E-Vision Smart Optics Inc. | Electro-active intraocular lenses |
| US20060219347A1 (en) * | 2005-04-04 | 2006-10-05 | Essilor International Compagnie Generale D'optique | Process for transferring coatings onto a surface of a lens substrate with most precise optical quality |
| US7258437B2 (en) * | 2005-09-07 | 2007-08-21 | Transitions Optical, Inc. | Photochromic multifocal optical article |
| US8105070B2 (en) * | 2006-12-21 | 2012-01-31 | Bausch & Lomb Incorporated | Apparatus and method for releasing a lens molded in a cavity between posterior and anterior mold sections |
| AR064985A1 (en) | 2007-01-22 | 2009-05-06 | E Vision Llc | FLEXIBLE ELECTROACTIVE LENS |
| BRPI0807560A2 (en) * | 2007-02-23 | 2014-07-01 | Pixeloptics Inc | DYNAMIC OPHTHALM OPENING |
| JP2010520514A (en) * | 2007-03-07 | 2010-06-10 | ピクセルオプティクス， インコーポレイテッド | Multifocal lens with progressive optical power region and discontinuity |
| US20090091818A1 (en) * | 2007-10-05 | 2009-04-09 | Haddock Joshua N | Electro-active insert |
| US7883207B2 (en) | 2007-12-14 | 2011-02-08 | Pixeloptics, Inc. | Refractive-diffractive multifocal lens |
| US20080273169A1 (en) * | 2007-03-29 | 2008-11-06 | Blum Ronald D | Multifocal Lens Having a Progressive Optical Power Region and a Discontinuity |
| WO2008153102A1 (en) | 2007-06-14 | 2008-12-18 | Aji Co., Ltd. | Method of molding, process for producing lens, molding apparatus, process for producing stamper, master production apparatus, stamper production system and stamper production apparatus |
| US7926941B2 (en) * | 2007-12-14 | 2011-04-19 | Pixeloptics Inc. | Multiple layer multifocal composite lens |
| US7744215B2 (en) * | 2007-12-25 | 2010-06-29 | Pixeloptics, Inc. | Multiple layer multifocal composite lens |
| AU2009225638A1 (en) | 2008-03-18 | 2009-09-24 | Pixeloptics, Inc. | Advanced electro-active optic device |
| US8154804B2 (en) * | 2008-03-25 | 2012-04-10 | E-Vision Smart Optics, Inc. | Electro-optic lenses for correction of higher order aberrations |
| EP2800993A2 (en) | 2012-01-06 | 2014-11-12 | HPO Assets LLC | Eyewear docking station and electronic module |
| CN104797404B (en) * | 2012-06-29 | 2018-04-27 | 庄臣及庄臣视力保护公司 | Lens precursor with the feature structure for manufacturing ophthalmic lens |
| CN105848864B (en) | 2013-11-20 | 2018-10-12 | 光学转变公司 | The method of coated lens and lens supports object |
| WO2015140104A1 (en) * | 2014-03-18 | 2015-09-24 | Essilor International (Compagnie Générale d'Optique) | A mould and process for manufacturing an ophthalmic lens equipped with an insert |
| EP3248054B1 (en) | 2015-01-22 | 2018-12-12 | Transitions Optical, Inc. | Optical article having a photoluminescent mark |
| US10599006B2 (en) | 2016-04-12 | 2020-03-24 | E-Vision Smart Optics, Inc. | Electro-active lenses with raised resistive bridges |
| EP3440508B1 (en) | 2016-04-12 | 2021-01-27 | E- Vision Smart Optics, Inc. | Electro-active lenses with raised resistive bridges |
| DE102018111368B3 (en) * | 2018-05-14 | 2019-04-25 | Carl Mahr Holding Gmbh | Workpiece holder, measuring device and measuring method for measuring a workpiece |
Family Cites Families (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2304217A (en) * | 1938-01-20 | 1942-12-08 | American Optical Corp | Method and apparatus for making lenses |
| US2360641A (en) * | 1940-08-14 | 1944-10-17 | American Optical Corp | Lens and process of making same |
| US2339433A (en) * | 1940-12-07 | 1944-01-18 | Eastman Kodak Co | Method of forming optical surfaces on plastic material |
| US2728106A (en) * | 1950-09-08 | 1955-12-27 | American Optical Corp | Means for producing optical elements |
| US2890486A (en) * | 1955-08-29 | 1959-06-16 | American Optical Corp | Mold for producing lens of any shape from a polymerizable material |
| GB796825A (en) * | 1955-10-04 | 1958-06-18 | American Optical Corp | Improvements in or relating to casting devices for optical elements |
| FR1136887A (en) * | 1955-10-06 | 1957-05-21 | American Optical Corp | Method and device for the manufacture of optical elements and in particular lenses |
| GB858218A (en) * | 1957-03-22 | 1961-01-11 | John Johnson | Method and apparatus for manufacturing optical elements from moulded polymer materials |
| GB846669A (en) * | 1959-03-11 | 1960-08-31 | American Optical Corp | Improvements in devices and methods of forming optical elements |
| US3248460A (en) * | 1963-02-28 | 1966-04-26 | Bausch & Lomb | Method of making lenses |
| US3422168A (en) * | 1964-12-01 | 1969-01-14 | Ppg Industries Inc | Process of casting resinous lenses in thermoplastic cast replica molds |
| US3423488A (en) * | 1966-05-11 | 1969-01-21 | Ppg Industries Inc | Process for casting resinous lenses in thermoplastic cast replica molds |
| US3460928A (en) * | 1967-06-09 | 1969-08-12 | American Optical Corp | Method of making lens molds |
| US3528135A (en) * | 1968-02-19 | 1970-09-15 | Armorlite Lens Co Inc | Gasket for molding plastic optical elements |
| DE1930291A1 (en) * | 1969-06-14 | 1970-12-17 | Rodenstock Optik G | Producing optical elements from plastics - material |
| US3555611A (en) * | 1969-12-15 | 1971-01-19 | Armorlite Lens Co Inc | Mold for casting optical elements and the like |
| US3946982A (en) * | 1974-09-03 | 1976-03-30 | Textron, Inc. | Adjustable mold for direct casting of plastic multifocal lenses |
-
1977
- 1977-06-27 US US05/810,357 patent/US4190621A/en not_active Expired - Lifetime
-
1978
- 1978-02-09 CA CA296,512A patent/CA1098268A/en not_active Expired
- 1978-02-20 IL IL54079A patent/IL54079A/en unknown
- 1978-03-02 NO NO780731A patent/NO780731L/en unknown
- 1978-03-06 DE DE19782809610 patent/DE2809610A1/en not_active Withdrawn
- 1978-03-06 CH CH243078A patent/CH625458A5/en not_active IP Right Cessation
- 1978-03-06 PT PT67745A patent/PT67745A/en unknown
- 1978-03-07 NL NL7802485A patent/NL7802485A/en not_active Application Discontinuation
- 1978-03-08 IT IT67493/78A patent/IT1108328B/en active
- 1978-03-08 FR FR7806614A patent/FR2383002A1/en active Granted
- 1978-03-08 ES ES467649A patent/ES467649A1/en not_active Expired
- 1978-03-08 BE BE185751A patent/BE864672A/en not_active IP Right Cessation
- 1978-03-08 FI FI780749A patent/FI780749A/en not_active Application Discontinuation
- 1978-03-09 DK DK105278A patent/DK105278A/en not_active Application Discontinuation
- 1978-03-09 IE IE488/78A patent/IE46344B1/en unknown
- 1978-03-09 GB GB9477/78A patent/GB1601327A/en not_active Expired
- 1978-03-09 SE SE7802719A patent/SE7802719L/en unknown
- 1978-03-09 JP JP2715978A patent/JPS53124570A/en active Pending
- 1978-12-16 ES ES476080A patent/ES476080A1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| IL54079A (en) | 1981-03-31 |
| IT7867493A0 (en) | 1978-03-08 |
| DK105278A (en) | 1978-09-11 |
| NO780731L (en) | 1978-09-12 |
| DE2809610A1 (en) | 1978-09-14 |
| JPS53124570A (en) | 1978-10-31 |
| FI780749A (en) | 1978-09-11 |
| FR2383002A1 (en) | 1978-10-06 |
| BE864672A (en) | 1978-07-03 |
| IE780488L (en) | 1978-09-10 |
| ES476080A1 (en) | 1979-08-16 |
| IT1108328B (en) | 1985-12-09 |
| US4190621A (en) | 1980-02-26 |
| ES467649A1 (en) | 1979-09-01 |
| NL7802485A (en) | 1978-09-12 |
| IE46344B1 (en) | 1983-05-04 |
| PT67745A (en) | 1978-04-01 |
| IL54079A0 (en) | 1978-04-30 |
| CH625458A5 (en) | 1981-09-30 |
| SE7802719L (en) | 1978-09-11 |
| GB1601327A (en) | 1981-10-28 |
| FR2383002B1 (en) | 1983-02-25 |
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