CA1274713A - Transmission projection screen and method of manufacturing same - Google Patents
Transmission projection screen and method of manufacturing sameInfo
- Publication number
- CA1274713A CA1274713A CA000534409A CA534409A CA1274713A CA 1274713 A CA1274713 A CA 1274713A CA 000534409 A CA000534409 A CA 000534409A CA 534409 A CA534409 A CA 534409A CA 1274713 A CA1274713 A CA 1274713A
- Authority
- CA
- Canada
- Prior art keywords
- grooves
- particles
- screen
- light
- approximately
- 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
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B21/00—Projectors or projection-type viewers; Accessories therefor
- G03B21/54—Accessories
- G03B21/56—Projection screens
- G03B21/60—Projection screens characterised by the nature of the surface
- G03B21/62—Translucent screens
- G03B21/625—Lenticular translucent screens
Abstract
ABSTRACT
The invention relates to a transmission projection screen having a high light output and a suitable contrast, for example for use in a projection television system, and a method of manufacturing such a screen. The projection screen comprises a transparent substrate having a front surface which is provided with mutually parallel ribs. At the bottom of the grooves between the ribs two individual layers of light-absorbing particles are provided. The particles are fixed by means of an adhesive layer 14.
The invention relates to a transmission projection screen having a high light output and a suitable contrast, for example for use in a projection television system, and a method of manufacturing such a screen. The projection screen comprises a transparent substrate having a front surface which is provided with mutually parallel ribs. At the bottom of the grooves between the ribs two individual layers of light-absorbing particles are provided. The particles are fixed by means of an adhesive layer 14.
Description
7~
~ 2010~-7738 The invention relates to a transmission projection screen comprising a transparent substrate having a front surface which is provided with mutually parallel ribs from which light issues during operation of the screen, grooves being present between the successive ribs, in which grooves an amount of light-absorbing particles is disposed whose average size is at least 20% of the width of the grooves measured at the halfway point of the depth of these grooves.
The invention also relates to a method of manufacturing a transmission pro-)ection screen.
Such a screen is used, for example, for displaying im-ages of alphanumeric data which are projected on the rear surface of the screen, for example, by a lens system with one or more cathode-ray tubes or by a film projector. The transparent ribs located at the front surface focus the light rays whlch are receiv-ed from the rear side and which issue via the apexes of the ribs.
The grooves between the ribs remain dark. In order to avoid reflection of ambient light from both the front side and the rear side of the screen, which would reduce the contrast of the image to be displayed, a light-absorbing material is disposed in the grooves.
Netherlands Patent Application NL 86000~2 describes a transmission projection screen and a method of manufacturing such a screen, in which method discrete black particles are deposited and fixed in the grooves. The black particles consist of, for example, soot or a ferritic material and have a dimension of maxi-1 -- .
, .
mally 7S% of the width of the grooves measured at the halfway point of the depth of these grooves. These steps were taken to provide a transmission projection screen in which there is only a very slight optical contact between the light-absorbing material and the substrate with the ribs, thereby leaving the light output of the screen substantially unaffected while improving the contrast.
It is an object of the invention to provide a trans-mission projection screen whose diffuse reflection of ambient light is less -than 6.5%, thereby further improving the image contrast.
This object is achieved in accordance with the invention by a transmission projection screen as described in the opening paragraph, which screen is further characterized in that the light-absorbing particles located in the grooves are divided into two layers, the first layer comprising particles having dimensions from approximately 20 to approximately 50% and the second layer compris-ing particles having dimensions from approximately 75 to approxi-mately 125~ of the width of the grooves measured at the halfway point the depth of these grooves.
In order to obtain a screen having a substantially re-duced reflection, it is efficient for the particles in the first layer to be in contact with the particles in the second layer~ for example, via an adhesive layer. This reduced reflection is obtain-ed because the layers act as blinds.
Unlike the projection screen described in Netherlands Patent Application NL 8600042, the light absorbing particles, particularly the second layer, are not entirely situated in the bottom half of the grooves. Although this leads to a reduction of the light output, the presence of two light-absorbing layers reduces the reflection to such an extent that a substantial improve-ment in image contrast is obtained.
Due to the relatively large dimension of the particles, few particles are needed to obtain the desired light a~sorption.
Because of the small number of particles there are only few con-tact areas between the particles and the walls of the ribs. The maximum particle size is dictated by the wish that the particles should penetrate the grooves as far as possible in order not to absorb the light issuing from the apexes of the ribs. Limiting the size of the particles is also desired in order to homogeneously fill the grooves in a longitudinal direction so as to obtain a screen having a smooth appearance. On the other hand, by using large particles it is precluded that any light-absorbing particies remain on the apexes of the ribs, for example at the location of a possible lens structure.
~ further object of the invention is to provide a method of manufacturing a transmission projection screen having light-absorbing particles in the grooves, in which also relatively large light-absorbing particles can readily be deposited in the grooves.
An additional object of the invention is to provide a method by means of which any type of light-absorbing particles can be deposited, even if they are not provided with a synthetic-resin layer.
This object is achieved in accordance wi.th the invention by a method which comprises the following steps:
- a substrate having mutually parallel ribs is coated with an excess of first light-absorbing particles having dimensions of from approximately 20 to appro~imately 50% of the width of the grooves measured at the halfway point of the depth of the grooves - a brush is moved over the screen in the longitudinal direction of the grooves, so that the first light-absorbing par-ticles are pressed to the bottom of the grooves and the excess particles are removed from the screen, - an excess of second light-absorbing particles i5 provided onto the screen, which particles have dimensions of from approxi-mately 75 to approximately 125~ of the width of the grooves measured at the halfway point of the depth of the grooves, - a brush is moved over the screen in the longitudinal direction of the grooves, so that the second light-absorbing particles are pressed to the bottom of the grooves and the excess particles are removed from the screen, - - the screen is coated with an amount of an adhesive which suffices to fill the grooves, which adhesive has a low solids content, - whilst drying the adhesive, connections are formed be-tween the light-absorbing particles and the walls of the grooves and amongst the particles themselves.
The light-absorbing layers must penetrate the - 3a -7~3 grooves as far as possihle, for that reason they are separa-tely applied and pressed with a brush, after which the ad-hesive is applied.
An advantage of this method is that after drying the adhesive layer does not have to be sticky, consequent-ly the screen obtained is hardly sensitive to contamination, for example, by dust.
The choice of the adhesive is dictated by the materials used for both the substrate with the ribs, and the light-absorbing particles.
In order to obtain that after drying the adhesive layer does not fill the grooves and does not adversely affect the shape of the ribs, the solids content of the adhesive layer to be applied is, preferably, from 0.5 to 20 ~ by weight. Thus, the internal reflection of the liqht in the ribs remains optimal.
A requirement which must be met by the light-absorbing particles is that they do not resolve into smaller particles when they are subjected to common mecha-nical treatments such as brushing, because this wouldnullify the desired effect of the invention. Suitable light-absorbing materials are, for example, soot, ferrite par-ticles, black synthetic-resin particles, black glass beads and short pieces of black glass fibre. The particles may 2s have any shape, provided that the number of contact areas between the partic]es and the walls oE the grooves does not increase. Preferably, particles having curved surfaces are used, for example convex particles, because in general they establish only point-like contacts with the substrate and the ribs. The particles may consist of smaller par-ticles provided that they are strongly bonded, for example by sintering.
The invention will now be further explained hy means of an example of an embodiment and with reference to a drawing, in which Fig. 1 is a perspective sectional view of a substrate having mutually parallel ribs, and in which Fig. 2a-d schematically represents a number of steps of the method in accordance with the invention.
Exemelary_embodiment.
Fig. 1 shows a substrate 1, for example a poly-methylmethacrylate, provided with ribs 2. The screen shown in the figure is flat, but the invention may also be applied to a slightly curved screen. The ribs 2 are pro-vided at the front surface ~ith a lens struct-lre 3. How-ever, dependent upon the desired optical characteristic of the screen the apexes of the ribs may have various shapes. Between the ribs 2 there are mainly V-shaped grooves 4. The grooves m~y a]so have, for example, a flat bottom. The rihs and the grooves may be formed on the sur-face of the substrate by means of, for example, a replica technique which is known per se, for example by means of a curable synthetic-resin composition, for example one that can be cured by U~7 light. In accordance with an alternative method, the ribs and grooves can also be formed in a substrate by means of hot pressing. The rear surface of the substrate (not shown in the figure) may also be provided with an optical element, for example a fresnel structure.
In accordance with the present exemplary embodi-ment, the pitch between the mutually parallel grooves, i.e.
the distance measured between the deepest points of two successive grooves is 289/um,the depth of the qrooves 4 is 430/um, the width of the grooves measured at the halEway point of the depth of the grooves is llO /um.
~ n excess of convex black ferrite particles 11 having dimensions from 25 to 50/um is di.sposed along one of the edqes of the screen. The black particles are lonyi-tudinally brushed into the grooves by means of a nylonbrush having bristles of lOO/um, see Fia . 2a.
The bristles of the nylon brush used all have the same dimens~ons which are selected so that the bristles can press the black particles deep into the grooves. Because of the desired reproducibility of the method, preferably, a rotating brush is used whose pressure on the screen can be accurately adjusted, and along which the screen is moved by mechanical means.
Subsequently, an excess of convex black ferrite particles 12 having dimensions from lO0 -to 125/um is dis-posed along one of the edges of the screen. The black particles are longitudinally brushed in-to the grooves by means of a nylon brush having bristles of 400/um, see Fig. 2b.
Next, a 2.5 ~ by weight solution of a poly-methylmethacrylate in, for example, ethylacetate/iso-propanol (volume ra-tio of the mixture 1 : 1) is applied to lo the surface. By capillary action the grooves 4 are filled with the adhesive 13, see Fig. 2c. If necessary, the excess adhesive is removed by means of an absorbing, non-fluff cloth.
Fig. 2d is a sectional view of the result ob-tained after evaporation of the solvent (for example, at 50C for 15 minutes). The polymethylmethacrylate adhesive layer 14 is situated almost exclusive]y at the location of the glued particles 11 and 12. The adhesive layer 14 is not sticky after the adhesive has dried.
The diffuse reflection measured at the projection screen thus manufactured is from 4 to 4.5 %. For the sakeof comparison it is to be noted that the diffuse reflection at a screen which, apart from the fact that it only has one layer of light-absorbing particles having dimensions from 50 to 80/um, is identical to the above-mentioned one, amounts to 8 to 9 % and that the diffuse reflection of a screen without a liqht-absorbing layer amounts to more than 15 ~.
The light output of the screen in accordance with the eYemplary embodiment is from 53 to 54 ~6 . A screen having a single light-absorbing layer has a light output from 57 to 58 ~. These measurements were carried out on screens having a somewhat rough surface; screens having a smooth surface may, however, have a light output of more than 60 % independent of the fact whether they have 1 or 2 light-absorbing layers.
The projection screenc manufactured in accordance wi-th the above-described exemplary embodiment have a high PHN 11 724 -7- 28~5-19~6 light output and a very good contrast, and they are sufficiently resistant to the action of mechanical in-fluences, moi.sture and cleaning agents.
~ 2010~-7738 The invention relates to a transmission projection screen comprising a transparent substrate having a front surface which is provided with mutually parallel ribs from which light issues during operation of the screen, grooves being present between the successive ribs, in which grooves an amount of light-absorbing particles is disposed whose average size is at least 20% of the width of the grooves measured at the halfway point of the depth of these grooves.
The invention also relates to a method of manufacturing a transmission pro-)ection screen.
Such a screen is used, for example, for displaying im-ages of alphanumeric data which are projected on the rear surface of the screen, for example, by a lens system with one or more cathode-ray tubes or by a film projector. The transparent ribs located at the front surface focus the light rays whlch are receiv-ed from the rear side and which issue via the apexes of the ribs.
The grooves between the ribs remain dark. In order to avoid reflection of ambient light from both the front side and the rear side of the screen, which would reduce the contrast of the image to be displayed, a light-absorbing material is disposed in the grooves.
Netherlands Patent Application NL 86000~2 describes a transmission projection screen and a method of manufacturing such a screen, in which method discrete black particles are deposited and fixed in the grooves. The black particles consist of, for example, soot or a ferritic material and have a dimension of maxi-1 -- .
, .
mally 7S% of the width of the grooves measured at the halfway point of the depth of these grooves. These steps were taken to provide a transmission projection screen in which there is only a very slight optical contact between the light-absorbing material and the substrate with the ribs, thereby leaving the light output of the screen substantially unaffected while improving the contrast.
It is an object of the invention to provide a trans-mission projection screen whose diffuse reflection of ambient light is less -than 6.5%, thereby further improving the image contrast.
This object is achieved in accordance with the invention by a transmission projection screen as described in the opening paragraph, which screen is further characterized in that the light-absorbing particles located in the grooves are divided into two layers, the first layer comprising particles having dimensions from approximately 20 to approximately 50% and the second layer compris-ing particles having dimensions from approximately 75 to approxi-mately 125~ of the width of the grooves measured at the halfway point the depth of these grooves.
In order to obtain a screen having a substantially re-duced reflection, it is efficient for the particles in the first layer to be in contact with the particles in the second layer~ for example, via an adhesive layer. This reduced reflection is obtain-ed because the layers act as blinds.
Unlike the projection screen described in Netherlands Patent Application NL 8600042, the light absorbing particles, particularly the second layer, are not entirely situated in the bottom half of the grooves. Although this leads to a reduction of the light output, the presence of two light-absorbing layers reduces the reflection to such an extent that a substantial improve-ment in image contrast is obtained.
Due to the relatively large dimension of the particles, few particles are needed to obtain the desired light a~sorption.
Because of the small number of particles there are only few con-tact areas between the particles and the walls of the ribs. The maximum particle size is dictated by the wish that the particles should penetrate the grooves as far as possible in order not to absorb the light issuing from the apexes of the ribs. Limiting the size of the particles is also desired in order to homogeneously fill the grooves in a longitudinal direction so as to obtain a screen having a smooth appearance. On the other hand, by using large particles it is precluded that any light-absorbing particies remain on the apexes of the ribs, for example at the location of a possible lens structure.
~ further object of the invention is to provide a method of manufacturing a transmission projection screen having light-absorbing particles in the grooves, in which also relatively large light-absorbing particles can readily be deposited in the grooves.
An additional object of the invention is to provide a method by means of which any type of light-absorbing particles can be deposited, even if they are not provided with a synthetic-resin layer.
This object is achieved in accordance wi.th the invention by a method which comprises the following steps:
- a substrate having mutually parallel ribs is coated with an excess of first light-absorbing particles having dimensions of from approximately 20 to appro~imately 50% of the width of the grooves measured at the halfway point of the depth of the grooves - a brush is moved over the screen in the longitudinal direction of the grooves, so that the first light-absorbing par-ticles are pressed to the bottom of the grooves and the excess particles are removed from the screen, - an excess of second light-absorbing particles i5 provided onto the screen, which particles have dimensions of from approxi-mately 75 to approximately 125~ of the width of the grooves measured at the halfway point of the depth of the grooves, - a brush is moved over the screen in the longitudinal direction of the grooves, so that the second light-absorbing particles are pressed to the bottom of the grooves and the excess particles are removed from the screen, - - the screen is coated with an amount of an adhesive which suffices to fill the grooves, which adhesive has a low solids content, - whilst drying the adhesive, connections are formed be-tween the light-absorbing particles and the walls of the grooves and amongst the particles themselves.
The light-absorbing layers must penetrate the - 3a -7~3 grooves as far as possihle, for that reason they are separa-tely applied and pressed with a brush, after which the ad-hesive is applied.
An advantage of this method is that after drying the adhesive layer does not have to be sticky, consequent-ly the screen obtained is hardly sensitive to contamination, for example, by dust.
The choice of the adhesive is dictated by the materials used for both the substrate with the ribs, and the light-absorbing particles.
In order to obtain that after drying the adhesive layer does not fill the grooves and does not adversely affect the shape of the ribs, the solids content of the adhesive layer to be applied is, preferably, from 0.5 to 20 ~ by weight. Thus, the internal reflection of the liqht in the ribs remains optimal.
A requirement which must be met by the light-absorbing particles is that they do not resolve into smaller particles when they are subjected to common mecha-nical treatments such as brushing, because this wouldnullify the desired effect of the invention. Suitable light-absorbing materials are, for example, soot, ferrite par-ticles, black synthetic-resin particles, black glass beads and short pieces of black glass fibre. The particles may 2s have any shape, provided that the number of contact areas between the partic]es and the walls oE the grooves does not increase. Preferably, particles having curved surfaces are used, for example convex particles, because in general they establish only point-like contacts with the substrate and the ribs. The particles may consist of smaller par-ticles provided that they are strongly bonded, for example by sintering.
The invention will now be further explained hy means of an example of an embodiment and with reference to a drawing, in which Fig. 1 is a perspective sectional view of a substrate having mutually parallel ribs, and in which Fig. 2a-d schematically represents a number of steps of the method in accordance with the invention.
Exemelary_embodiment.
Fig. 1 shows a substrate 1, for example a poly-methylmethacrylate, provided with ribs 2. The screen shown in the figure is flat, but the invention may also be applied to a slightly curved screen. The ribs 2 are pro-vided at the front surface ~ith a lens struct-lre 3. How-ever, dependent upon the desired optical characteristic of the screen the apexes of the ribs may have various shapes. Between the ribs 2 there are mainly V-shaped grooves 4. The grooves m~y a]so have, for example, a flat bottom. The rihs and the grooves may be formed on the sur-face of the substrate by means of, for example, a replica technique which is known per se, for example by means of a curable synthetic-resin composition, for example one that can be cured by U~7 light. In accordance with an alternative method, the ribs and grooves can also be formed in a substrate by means of hot pressing. The rear surface of the substrate (not shown in the figure) may also be provided with an optical element, for example a fresnel structure.
In accordance with the present exemplary embodi-ment, the pitch between the mutually parallel grooves, i.e.
the distance measured between the deepest points of two successive grooves is 289/um,the depth of the qrooves 4 is 430/um, the width of the grooves measured at the halEway point of the depth of the grooves is llO /um.
~ n excess of convex black ferrite particles 11 having dimensions from 25 to 50/um is di.sposed along one of the edqes of the screen. The black particles are lonyi-tudinally brushed into the grooves by means of a nylonbrush having bristles of lOO/um, see Fia . 2a.
The bristles of the nylon brush used all have the same dimens~ons which are selected so that the bristles can press the black particles deep into the grooves. Because of the desired reproducibility of the method, preferably, a rotating brush is used whose pressure on the screen can be accurately adjusted, and along which the screen is moved by mechanical means.
Subsequently, an excess of convex black ferrite particles 12 having dimensions from lO0 -to 125/um is dis-posed along one of the edges of the screen. The black particles are longitudinally brushed in-to the grooves by means of a nylon brush having bristles of 400/um, see Fig. 2b.
Next, a 2.5 ~ by weight solution of a poly-methylmethacrylate in, for example, ethylacetate/iso-propanol (volume ra-tio of the mixture 1 : 1) is applied to lo the surface. By capillary action the grooves 4 are filled with the adhesive 13, see Fig. 2c. If necessary, the excess adhesive is removed by means of an absorbing, non-fluff cloth.
Fig. 2d is a sectional view of the result ob-tained after evaporation of the solvent (for example, at 50C for 15 minutes). The polymethylmethacrylate adhesive layer 14 is situated almost exclusive]y at the location of the glued particles 11 and 12. The adhesive layer 14 is not sticky after the adhesive has dried.
The diffuse reflection measured at the projection screen thus manufactured is from 4 to 4.5 %. For the sakeof comparison it is to be noted that the diffuse reflection at a screen which, apart from the fact that it only has one layer of light-absorbing particles having dimensions from 50 to 80/um, is identical to the above-mentioned one, amounts to 8 to 9 % and that the diffuse reflection of a screen without a liqht-absorbing layer amounts to more than 15 ~.
The light output of the screen in accordance with the eYemplary embodiment is from 53 to 54 ~6 . A screen having a single light-absorbing layer has a light output from 57 to 58 ~. These measurements were carried out on screens having a somewhat rough surface; screens having a smooth surface may, however, have a light output of more than 60 % independent of the fact whether they have 1 or 2 light-absorbing layers.
The projection screenc manufactured in accordance wi-th the above-described exemplary embodiment have a high PHN 11 724 -7- 28~5-19~6 light output and a very good contrast, and they are sufficiently resistant to the action of mechanical in-fluences, moi.sture and cleaning agents.
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A transmission projection screen comprising a transparent substrate having a front surface which is provided with mutually parallel ribs from which light issues during operation of the screen, grooves being present between the successive ribs, in which grooves an amount of light-absorbing particles is disposed whose average size is at least 20% of the width of the grooves measured halfway the depth of these grooves, characterized in that the light-absorbing particles in the grooves are divided into two layers, the first layer comprising particles having dimensions from approximately 20 to approximately 50% and the second layer comprising particles having dimensions from approximately 75 to approximately 125% of the width of the grooves measured halfway the depth of these grooves.
2. A transmission projection screen as claimed in Claim 1, characterized in that the particles in the first layer are in contact with the particles in the second layer.
3. A method of manufacturing a transmission projection screen as claimed in Claim 1 or 2, characterized in that the method comprises the following steps:
- a substrate having mutually parallel ribs is provided with an excess of first light-absorbing particles whose dimensions are from approximately 20 to approximately 50% of the width measured at the halfway point of the depth of the grooves, - a brush is moved over the screen in the longitudinal direction of the grooves, so that the first light-absorbing particles are pressed to the bottom of the grooves and the excess particles are removed from the screen, - an excess of second light-absorbing particles is provid-ed onto the screen, which particles have dimensions from approxi-mately 75 to approximately 125% of the width of the grooves measured at the halfway point of the depth of the grooves, - a brush is moved over the screen in the longitudinal direction of the grooves, so that the second light-absorbing par-ticles are pressed to the bottom of the grooves and the excess particles are removed from the screen, - the screen is coated with an amount of an adhesive which suffices to fill the grooves, which adhesive has a low solids content, - whilst drying the adhesive, connections are formed be-tween the light-absorbing particles and the walls of the grooves and amongst the particles themselves.
- a substrate having mutually parallel ribs is provided with an excess of first light-absorbing particles whose dimensions are from approximately 20 to approximately 50% of the width measured at the halfway point of the depth of the grooves, - a brush is moved over the screen in the longitudinal direction of the grooves, so that the first light-absorbing particles are pressed to the bottom of the grooves and the excess particles are removed from the screen, - an excess of second light-absorbing particles is provid-ed onto the screen, which particles have dimensions from approxi-mately 75 to approximately 125% of the width of the grooves measured at the halfway point of the depth of the grooves, - a brush is moved over the screen in the longitudinal direction of the grooves, so that the second light-absorbing par-ticles are pressed to the bottom of the grooves and the excess particles are removed from the screen, - the screen is coated with an amount of an adhesive which suffices to fill the grooves, which adhesive has a low solids content, - whilst drying the adhesive, connections are formed be-tween the light-absorbing particles and the walls of the grooves and amongst the particles themselves.
4. A method as claimed in Claim 3, characterized in that prior to drying the solids content of the adhesive is from 0.5 to 20% by weight.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL8600944 | 1986-04-15 | ||
| NL8600944A NL8600944A (en) | 1986-04-15 | 1986-04-15 | PROJECTION SCREEN VIEW AND METHOD OF MANUFACTURING THE SAME |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1274713A true CA1274713A (en) | 1990-10-02 |
Family
ID=19847876
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000534409A Expired CA1274713A (en) | 1986-04-15 | 1987-04-10 | Transmission projection screen and method of manufacturing same |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4688093A (en) |
| EP (1) | EP0241986B1 (en) |
| JP (1) | JPH0746196B2 (en) |
| CA (1) | CA1274713A (en) |
| DE (1) | DE3772428D1 (en) |
| DK (1) | DK168025B1 (en) |
| NL (1) | NL8600944A (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3785308T2 (en) * | 1986-12-05 | 1993-09-30 | Philips Nv | Translucent screen and method of making such a screen. |
| US4964695A (en) * | 1987-10-06 | 1990-10-23 | North American Philips Corporation | Lenticular arrays for front projection screens and contrast improving method and device |
| US4927233A (en) * | 1989-03-06 | 1990-05-22 | Mitsubishi Rayon Co., Ltd. | Rear projection screen |
| US5121252A (en) * | 1990-05-11 | 1992-06-09 | Mitsubishi Rayon Co., Ltd. | Projection screen and method for producing the same |
| EP0542548B1 (en) * | 1991-11-15 | 2000-04-26 | Matsushita Electric Industrial Co., Ltd. | Transmission type screen and method of manufacturing thereof |
| US5481385A (en) * | 1993-07-01 | 1996-01-02 | Alliedsignal Inc. | Direct view display device with array of tapered waveguide on viewer side |
| US5521726A (en) * | 1994-08-26 | 1996-05-28 | Alliedsignal Inc. | Polarizer with an array of tapered waveguides |
| US5657408A (en) * | 1994-12-23 | 1997-08-12 | Alliedsignal Inc. | Optical device comprising a plurality of units having at least two geometrically-differentiated tapered optical waveguides therein |
| US6010747A (en) * | 1996-12-02 | 2000-01-04 | Alliedsignal Inc. | Process for making optical structures for diffusing light |
| US6600599B2 (en) | 1998-06-09 | 2003-07-29 | Avery Dennison Corporation | Rear projection screens and light filters with conformable coatings and methods of making the same |
| US6417966B1 (en) * | 1999-07-07 | 2002-07-09 | 3M Innovative Properties Company | Rear projection screen using internal reflection |
| US6597417B1 (en) * | 2000-07-25 | 2003-07-22 | Scram Technologies, Inc. | Optical panel having black material between apexes of serrations on the inlet face |
| US7072109B2 (en) | 2002-06-27 | 2006-07-04 | Dai Nippon Printing Co., Ltd. | Projection screen and projection display |
| US6871962B2 (en) * | 2002-10-01 | 2005-03-29 | Hitachi Electronic Devices, Inc. | Projection coupler with dual channel sealing mechanism |
| US7453634B2 (en) * | 2005-03-07 | 2008-11-18 | Avery Dennison Corporation | Discontinuous or variable thickness gain modification coating for projection film and method for making same |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58145933A (en) * | 1982-02-25 | 1983-08-31 | Mitsubishi Rayon Co Ltd | Back projection screen |
| JPS59121034A (en) * | 1982-12-27 | 1984-07-12 | Mitsubishi Rayon Co Ltd | Transmission type screen |
| US4573764A (en) * | 1983-12-30 | 1986-03-04 | North American Philips Consumer Electronics Corp. | Rear projection screen |
| EP0154053B1 (en) * | 1983-12-30 | 1990-02-28 | Koninklijke Philips Electronics N.V. | Projection screen |
-
1986
- 1986-04-15 NL NL8600944A patent/NL8600944A/en not_active Application Discontinuation
- 1986-07-30 US US06/891,983 patent/US4688093A/en not_active Expired - Fee Related
-
1987
- 1987-04-06 EP EP87200638A patent/EP0241986B1/en not_active Expired
- 1987-04-06 DE DE8787200638T patent/DE3772428D1/en not_active Expired - Lifetime
- 1987-04-10 CA CA000534409A patent/CA1274713A/en not_active Expired
- 1987-04-10 DK DK186787A patent/DK168025B1/en not_active IP Right Cessation
- 1987-04-15 JP JP62091093A patent/JPH0746196B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0241986B1 (en) | 1991-08-28 |
| JPS62245239A (en) | 1987-10-26 |
| DK168025B1 (en) | 1994-01-17 |
| US4688093A (en) | 1987-08-18 |
| DE3772428D1 (en) | 1991-10-02 |
| EP0241986A1 (en) | 1987-10-21 |
| NL8600944A (en) | 1987-11-02 |
| DK186787A (en) | 1987-10-16 |
| DK186787D0 (en) | 1987-04-10 |
| JPH0746196B2 (en) | 1995-05-17 |
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| MKLA | Lapsed |