WO1997035216A1

WO1997035216A1 - Coated film for applying to light transmitting articles

Info

Publication number: WO1997035216A1
Application number: PCT/AU1997/000168
Authority: WO
Inventors: Clive Hilton Burton
Original assignee: Sola International Holdings Ltd.
Priority date: 1996-03-15
Filing date: 1997-03-14
Publication date: 1997-09-25
Also published as: AUPN871296A0

Abstract

A film (1) is disclosed for laminating to an ophthalmic lens (2). The film comprises a film substrate, a hard coat, an AR coat, and optionally also a lubricious coating. The coatings can be applied to the film substrate using liquid application techniques such as spin coating. The film (1) is typically laminated to the rear surface (3) of a lens (2) after the lens (2) has been surfaced in a prescription laboratory. This obviates the need to have expensive vacuum deposition apparatus in a prescription laboratory.

Description

COATED FILM FOR APPLYING TO LIGHT TRANSMITTING ARTICLES

This invention relates to light transmitting articles. More specifically this

invention relates to coatings for light transmitting articles.

This invention relates particularly to coatings for optical lenses such as

ophthalmic lenses and it will be convenient to hereinafter describe the invention

with reference to this example application. It is to be understood however that

the invention is capable of broader application. Merely by way of example, the

invention might also find application in lenses for disposable cameras,

binoculars and transparent covers for picture frames.

Spectacle or ophthalmic lenses are generally manufactured in two basic

forms, namely stock lenses and semifinished lenses. Stock lenses are

moulded with their front and rear surfaces polished and only require peripheral

edging in a prescription laboratory before being fitted to a frame. By contrast the concave rear surfaces of semi-finished lenses still require surfacing and

polishing when they leave the manufacturing site. Because the surfacing of the

rear surface is dependent upon a wearer's prescription it can only be done in a

prescription laboratory.

Spectacle lenses are made from glass and from plastic. Plastic lenses

have been known for some time and are increasingly being preferred to glass lenses for spectacles. Plastic lenses are lighter than glass lenses and can be

made thinner than glass lenses.

Plastic lenses are typically coated with at least one, and typically three to

seven coatings to improve their durability and performance. The coatings

which are frequently applied to plastic lenses are firstly a hard coat to increase

the abrasion resistance of the softer underlying plastic lens substrate, and

secondly an AR coat or coating (anti-reflection coating) to reduce unwanted

reflection of light. Other coatings which may also be applied to the lens are a

primer coat to improve the fracture resistance of an AR coated lens and a coating of lubricious material for easing cleaning of the lens. Where the term

"multi-coat" is used in the specification it is intended to describe coatings of this

general nature.

Plastic lenses may also be coated with other optically effective coatings

including sunlens coatings, mirror coatings, photochromic coatings and tint

coatings.

A hard coat generally comprises an inorganic compound linked to an

organic matrix for the purpose of increasing the abrasion resistance of the

softer, underlying lens body. The hard coating is typically 1 to 10 micron thick. Hard coats are typically applied by liquid application techniques such as

roller coating, dipping or spinning of liquids. However hard coats may also be

applied by vacuum deposition techniques such as Plasma Polymerisation (PP)

or Plasma Enhanced Chemical Vapour Deposition (PECVD).

An AR coating, as described above, reduces unwanted reflection of light

and thereby enables the wearer to see and be seen more clearly. Typically a

high quality AR coating reduces the natural (photopic) reflectance of glass or

plastic from 4% to 8% per surface to well under 0.5% per surface. Some

known AR coatings comprise three to five layers of metal or semi-metal oxides,

such TiO₂ and SiO₂, arranged in the form of an interference stack. The design

of the interference stack is well known to those skilled in the art of vacuum deposition of optical multi-layer thin films. The thickness of the layers in the

multi-layer stack typically ranges from 10 nanometres to several hundred

nanometres. The thickness and uniformity of the layers in the stack must be

carefully controlled. It is well recognised that AR coatings of this general type are quite brittle and are not resilient.

AR coatings are typically deposited in high technology vacuum

deposition systems employing electron beam (e-beam) evaporation and in

some cases ion assisted deposition (IAD). The application of AR coatings to

plastic lenses by vacuum deposition techniques is fraught with difficulties.

Often problems are encountered in getting the AR coat to satisfactorily adhere to the lens substrate. One problem is the limitation on the temperature to which

the plastic substrate may be heated during deposition. Another problem is that

vacuum deposition requires a pristine lens substrate surface. Any dirt or

imperfection on the surface of the lens will detract from the coating, and may

make it commercially unacceptable. A further problem is that vacuum

deposition apparatus is very expensive and requires highly skilled personnel if it

is to be operated effectively.

Primer coatings may be applied to AR coated lenses to improve the fracture resistance thereof. The primer coating, which typically is made of

polyurethane, is applied between the surface of the lens and the hard coating to

stop cracks propagating from the brittle AR coating into the lens.

A lubricious or easyclean coating typically comprises a very thin layer of

lubricious organic film which is applied to the outermost coating on the lens to

facilitate cleaning of the lens. The lubricious coating might also be provided

with hydrophobic and/or anti-static properties.

As described above, the concave rear surface of a semi-finished lens

cannot undergo final surfacing and polishing at the point of manufacture

because this is done in a prescription laboratory according to the wearer's

prescription. These final coatings either have to be applied to the lens in the prescription laboratory or else they have to be forwarded from the prescription

laboratory to a central processing facility for the coatings.

The problems of vacuum deposition of AR coatings described above are

exacerbated in a prescription laboratory. The pristine conditions required for

satisfactory AR coating by vacuum deposition are often difficult to obtain within

prescription laboratories. Further the high cost of apparatus and skilled

operating personnel may be more difficult to justify in a prescription laboratory

which may process only five to ten pairs of semi-finished lenses per day.

An additional problem encountered in applying an AR coating to a lens in

a prescription laboratory is that different lenses from a variety of manufacturers

often need to be coated at about the same time. However the lenses of

different manufacturers are made of different materials and require different

coatings. There is no standard hard coat and AR coat which can be applied to

all finished lenses. It is generally difficult to efficaciously coat lenses made of different materials using the same piece of equipment.

At the same time, it is not commercially attractive to send a semifinished

lens, once it has been surfaced and polished according to a wearer's

prescription, to a centralised coating facility. Prescription laboratories require the ability to finish and fit lenses quickly and efficiently thereby providing the

customer with a quick turnaround time, eg less than 24 hours. It would therefore be advantageous if a way of applying an optically effective coat,

particularly an AR coat, speedily and simply to a lens in a prescription

laboratory could be devised.

It is therefore an object of this invention to provide a coat or coating for a

lens which can be speedily and simply applied to a lens in a prescription

laboratory.

According to a first aspect of this invention there is provided a film for

applying to a light transmitting article including:

a film substrate; and

an optically effective coat applied to the film substrate for improving the

optical properties of a light transmitting article to which the film is applied.

Typically the film substrate is a thin polymeric film. In order for the film to

be capable of conforming closely to both concave and convex lens surfaces it

would have to be flexible and extensible, eg it would need to be sufficiently

durable to withstand stretching during lamination. It would also need to be able

to withstand wear and tear in use.

Advantageously the film substrate is polyethylene terephthalate (PET).

PET is sold by Du Pont in Australia under the trademark MYLAR. PET can withstand temperatures well in excess of 100°C which may permit sol-gel and nanotechnology approaches to optical thin film deposition to be used. PET has

the additional advantage that its glass transition temperature of approximately

67°C allows the film substrate to be deformed by the application of moderate

heat and thus conform to a convex or concave lens surface.

Alternatively the film substrate may be cellulose acetyl butyrate (CAB).

The optically effective coat may be an AR coat for reducing unwanted

reflection of a light source.

Preferably the AR coat comprises an organic based multi-layer coat.

Each layer may comprise nanometric particles of inorganics in an organic

matrix which permits some degree of stretch formation, eg a polysiloxane

compound. Preferably the AR coat comprises a layer containing titanium

compounds sandwiched between two layers containing polysiloxanes which are

substantially titanium-free. Typically the titanium containing layers contain up to 10 weight per cent titanium dioxide.

It is particularly preferred that the layer of the AR coat proximate to the

film substrate contains polysiloxane resins, colloidal silica, organic dicarboxylic

acid and surfactants. Particularly suitable AR coats are described in United States patents

5,104,692 and 5,173,368 assigned to Pilkington Visioncare Holdings Ine, the

entire contents of which are incorporated herein by reference. The two and

three layer AR coats disclosed in those patents are very suitable. The two and

three layer designs disclosed in the above patents can be extended to four or

five layer designs, or even designs having a greater number of layers.

At the same time however it is to be clearly understood that coatings

other than those described in the above referenced US Patents may be also be

used.

Naturally the AR coat would have to be capable of withstanding the

compressive and tensile forces encountered when the film was conformed to a

lens surface during lamination, ie it would need to be both flexible and

extensible. Conventional vacuum deposited AR coats which comprise ceramic

coatings such as SiO₂, TiO₂, Nb₂O₅, AI₂O₃, SiN, and other metal and semi-

metal oxides and nitrides, are brittle and will crack or craze if attempts are

made to stretch and deform them. A polysiloxane multilayer AR coat is much

more flexible than a conventional ceramic AR coat applied by vacuum

deposition.

The extensibility of the materials described in US Patents 5,104,692 and 5,173,368 above can be further enhanced by the addition of a suitable flexibility enhancing agent such as dimethylsiloxane. The flexibility enhancing agent may

comprise up to 10% by weight of the coating.

Altematively the optically effective coat may confer the effect of a

sunlens, a tinted lens, a mirror coated lens, or any combination of these effects.

The film may further include a hard coat sandwiched between the film

substrate and the optically effective coat, eg AR coat.

Advantageously the hard coat comprises an inorganic compound linked

to an organic matrix, eg a polysiloxane.

Optionally the film may include a lubricious organic coating applied to the optically effective coat to facilitate easy cleaning of the article. Further

optionally the film may include a primer coat of polyurethane positioned

between the film substrate and the AR coat.

The optically effective coat may be applied by liquid film application

techniques and the hard coat may also be applied by liquid film application

techniques. Suitable techniques inlude curtain flow coating, dip coating, roller

coating and spin coating. The lubricious organic coating may also be applied

by liquid film application techniques. Naturally liquid coating techniques are substantially less complicated

than the vacuum deposition techniques which have traditionally been used to

deposit AR coats. Liquid film application techniques are also substantially

cheaper than vacuum deposition techniques and accordingly there is a strong

cost incentive to apply the coatings in this fashion. Liquid film application

techniques would be vastly more difficult to use on the variably curved surfaces

of lenses than on thin flat film.

Alternatively, the optically effective coat and the hardcoat may be

deposited by vacuum deposition techniques, eg e-beam evaporation (with or

without IAD), PP and PECVD. The vacuum applied hard coat and optically effective coat may be rendered extensible without cracking by the inclusion of

organic compounds in both coatings. These organic compounds include

monomeric vapours of the type used to create organic hardcoats by means of

plasma polymerisation, eg siloxanes, alkyl- and alkoxysilanes. The lubricious

organic coating may also be applied using these techniques.

Finally the optically effective coat, eg the AR coat would typically be

designed such that it underwent minimal change in residual reflectance colour

or other optical property when the thickness of each layer was reduced at a

given point on the lens as a result of stretching the coated film to conform to the

lens shape. The design necessary to obtain residual reflectance colour stability for AR coats would be well known to those skilled in the art of optical multi-layer

thin film design and will not be described in further detail here.

According to a second aspect of this invention there is provided a light

transmitting article including an article substrate, and a film applied to the article

substrate, the film including a film substrate and an optically effective coat

applied to the film substrate.

The film may include any one or more of the preferred features

described above with respect to the first aspect of the invention.

Typically the light transmitting article is an ophthalmic lens having front

and rear surfaces.

Typically the film is applied to at least the rear surface of the lens.

Optionally the film may be applied to both the front and rear surfaces of the lens.

Advantageously the film is adhered to the lens by means of a UV curable

adhesive. Adhesives having acrylate functionality are particularly preferred.

According to a third aspect of this invention there is provided apparatus

for laminating a film to an ophthalmic lens, including means for drawing the film tautly across a flat or substantially convex surface of the lens such that it conformingly engages the surface of the lens.

Advantageously the means for drawing the film across the surface of the

lens comprises a pair of laminating rings.

Advantageously the apparatus also includes a film deforming member

for urging the film into conforming engagement with a substantially concave

surface of the lens.

In one embodiment, the film deforming member includes a bladder

having a flexible wall for urging the film into conforming engagement with the

surface of the lens when the bladder is filled with fluid under pressure.

Preferably the apparatus further includes a UV source for irradiating a

UV curable adhesive with UV radiation so as to adhere the film to the lens.

Optionally the apparatus also includes means for placing a drop of

adhesive substantially centrally on a surface of the lens.

Apparatus in accordance with this invention for laminating a film in

accordance with this invention to a lens may come in a variety of forms. It will

be convenient to hereinafter describe in detail an example embodiment of the film and an example embodiment of the apparatus with reference to the

accompanying drawings. It is to be understood however that the specific

nature of this embodiment does not supersede the generality of the proceeding

statements. In the drawings:

Figs 1 and 2 are schematic sectional front views of apparatus being used

to apply a multi-coated film to a convex surface of a lens;

Fig 3 is a three-dimensional view of the apparatus, film and lens of Fig 2;

and

Figs 4 and 5 are schematic sectional front views of apparatus being used

to apply a multi-coated film to a concave surface of a lens.

Figs 1 to 3 show inter alia a film 1 and an ophthalmic lens 2.

The film 1 comprises a film substrate which is coated with a hardcoat, an

optically effective coat which is an AR coat, and a lubricious coat. The

substrate is typically made of PET which is sold under the trade mark MYLAR

by Du Pont in Australia. Special optically clear and homogeneous grades of

PET are known and are preferable for this application. The hard coat typically

comprises a polysiloxane compound. The AR coat is typically a three layer

coating composition containing a middle layer of titanium compound sandwiched between two layers containing polysiloxane compound.

Particularly suitable AR coatings of this type are disclosed in United States

patent 5,173,368 which is assigned to Pilkington Visioncare Holdings Limited.

The lubricious coating facilitates easy cleaning of the lens. The various

coatings applied to the substrate which are collectively referred to as a "multi-

coat" are not shown in the drawings.

The coatings are typically applied to the film substrate by liquid

application techniques. Roll coating is particularly preferred for the application

of these coatings to the film substrate. The film is typically produced in sheets

or rolls and then distributed to the sites at which it is laminated to the lenses, eg

prescription laboratories.

The ophthalmic lens has a convex front surface 3 and a concave rear

surface 4 as is typical for these lenses. The rear surface is surfaced, and

possibly also polished, according to the wearer's prescription in the prescription

laboratory and once this has been done the lens is ready to have the film

laminated thereto.

An appropriately configured piece of film is cut from the roll and

stretched tautly across the surface 3 of the lens 2 spaced from the surface 3.

The film 1 is held in this position by being clamped between a pair of circular

laminating rings 5, one ring 5 being mounted over each major surface of the film 1. The rings 5 are connected to each other by screws forming a ring

assembly, although any other fastening means could equally be used.

Typically the rings 5 are made of metal although other suitable materials may

also be used.

A drop of adhesive 6 is disposed between the film 1 and the lens 2 for

adhering the film 1 to the lens 2 when it is drawn across the lens. The drop of

adhesive 6 is typically positioned over the centre of the surface 3 of the lens 2

and remains there due to surface tension. The drawing shows the drop spaced

from the surface 3 for the purposes of clarity of illustration only.

While other types of glue may be used, the glue used in the illustrated

embodiment, is of the type which is cured by UV radiation. Adhesives with

acrylate functionality are particularly suitable. UV radiation is provided by a UV

light source 7. The light source 7 is positioned above the lens 2 such that the film 1 is positioned in between the source 7 and the lens 2. The structure and

functioning of the UV source 7 would be well known to persons skilled in the art

and will not be described in further detail here.

As indicated above, other glues may also be used. For example, a so-

called super glue, or isocyanate glue may also be used. Isocyanate glues cure

anaerobically when oxygen is excluded from the atmosphere surrounding the

glue and certain minimum dimensions for the layer of glue are met. The use of an adhesive to adhere the film to the lens overcomes many of the problems encountered in the prior art vacuum deposition techniques.

The bonding of the film to the lenses is efficacious and is not prone to

delamination provided the surfaces of the thin polymeric film and the lens are

appropriately pretreated. Further the fact that the film and the substrate may be

made of different materials for different lens materials does not substantially

affect the laminating procedure. While different films will be used for different

lenses, the laminating procedure will be essentially the same for each. Further

the lens surface does not have to be cleaned and dried to the exacting

standards required for commercially acceptable vacuum deposition.

The film 1 may be heated above its glass transition temperature to aid

deformation and therefore conformance with the convex lens surface by hot air.

It must be understood however that heating equipment for blowing hot air has

not been illustrated in the drawings.

The film 1 is laminated to the lens 2 by moving the rings 5 downwardly

over the surface 3 of the lens 2 so that the film 1 is drawn tautly across the lens

2. Fig 2 illustrates the relative positioning of the components at this stage of

the laminating process. By drawing the film 1 tautly across the surface 3, the

glue 6 is spread evenly over the surface 3. When all air has been excluded from the film-lens interface, the glue 6 is irradiated with UV light from the UV

light source 7.

Figs 4 and 5 show the lamination of a film 1 to a concave rear surface 4

of a lens 2. While this lamination process is more complex than that illustrated

in Figs 1 and 2, many of the components of the apparatus are the same. The

same reference numerals shall be used to refer to the same components,

unless otherwise specified.

In Fig 4, the concave surface 4 of the lens 2, rather than the surface 3 is

closely spaced from the film 1 which is again clamped between a pair of circular

laminating rings 5.

There is an additional component for which there is no equivalent in Figs

1 and 2, namely a film deforming member 8. The member 8 comprises a

bladder housing a flexible, fluid impermeable, polymeric membrane 10 and a

rigid planar base element 11. The bladder may be filled with air, water, silicone

or other suitable UV transparent fluid which may be heated above the glass

transition temperatures of the film (eg above about 67°C for PET). Both the

membrane 10 and the base element 11 are UV transparent. The membrane 10

is clamped onto one surface of a circular ring 12, which is similar in construction

to one of the rings 5 while the base element 11 is mounted to an opposed

surface of the ring 12. The membrane 10, base element 11 , and ring 12, together form an inflatable bag which can be inflated by pumping fluid through

an fluid inlet port 13 having an appropriate valve means.

As in Figs 1 and 2, a drop of glue 6 is positioned on the surface 4,

substantially centrally relative thereto. Fig 4 shows the drop spaced from the

surface 4 for the purpose of clarity of illustration only.

The manner in which the film 1 is laminated to the surface 4 of the lens 2

is quite different to that in the Fig 1 and 2 embodiments. Instead of rings 5 being moved towards the lens 2, the bag is inflated such that the membrane 10

urges the film 1 outwardly into conforming engagement with the surface 4 of the

lens 2. Fig 5 shows the components substantially in this position although the

membrane 10 is shown spaced a small distance away from the film 1 for clarity only. As in Fig 1 , this action spreads the glue evenly across the surface of the

lens 2. Once all air is excluded from the film-lens interface, the glue is

irradiated with UV light from the source 7. When the glue has cured, the

finished lens complete with multi-coat applied thereto can be removed.

Thus a film can be speedily and easily applied in a prescription

laboratory by inexperienced personnel using the laminating apparatus

illustrated in Figs 4 and 5. A multi-coat might also be applied to the convex

surface 3 of the lens. An advantage of a preferred embodiment of this invention, is that a lens

can be coated simply and speedily with an AR coat and a hardcoat at a

prescription laboratory which does not have sophisticated vacuum deposition

equipment. Small prescription laboratories will be able to simply and speedily

apply multi-coats to spectacle lenses using only inexpensive laminating

equipment of the type already available in many prescription laboratories for laminating lens components together.

A further advantage of a preferred embodiment of this invention is that

the AR coat is more securely adhered to the lens than with the vacuum deposition processes. This is particularly important in a prescription laboratory

where lenses made from different materials need to be provided with a multi-

coat. Using the existing processes, difficulties are often encountered in

obtaining satisfactory adhesion of the multi-coat to the different lens materials.

A further advantage is that the surface of the lens to which the film is to be

laminated would not have to be as scrupulously clean and free of moisture as

would be the case were the known vacuum deposition techniques to be used.

A further advantage of a preferred embodiment of this invention is that it

may obviate the need to polish a lens after surfacing thereof Current state of

the art surfacing machines are able to produce surfaces which have a fine surface finish. It is quite possible that such surfaces will not need polishing

prior to laminating with the film of this invention to produce a multi-coated lens. It has long been recognised that it would be desirable to eliminate the step of

polishing a lens. Several attempts have been made to introduce so-called "cut

and coat" technology which directly coats the rear concave surface of the lens,

after surfacing, with a hard coat for covering over the surface texture and

blemishes. However, such attempts have not so far proved satisfactory.

A yet further advantage of a preferred embodiment of the invention, is

that it is technically easier and therefore less expensive to apply a multi-coat to

a flat, horizontal, continuous roll of film than it is to apply such a multi-coat to

discrete lenses, particularly the curved surfaces thereof. There are substantial

handling difficulties and thereby substantial costs associated with sending individual lenses through a plurality of coating processes. Further, the yields of

each coating process are typically only 90%-95% when coating individual

lenses, and would be substantially higher when coating continuous film.

Further it is possible to use liquid film application processes such as roll coating

to coat the film instead of difficult vacuum deposition processes. These liquid

application processes could not easily be used to coat lenses.

It is to be understood that various alterations, modifications, and/or

additions may be introduced into the constructions and arrangements of parts

previously described without departing from the ambit of the invention disclosed

herein.

Claims

1. A film for applying to a light transmitting article including:

a film substrate; and

an optically effective coat applied to the film substrate for improving the

2. A film according to Claim 1 , wherein the film substrate is a polymeric film.

3. A film according to Claim 2, wherein the film substrate is polyethylene

terephthalate (PET).

4. A film according to Claim 2, wherein the film substrate is cellulose acetyl

butyrate (CAB).

5. A film according to any one of Claims 1 to 4, wherein the optically

effective coat is an AR coat for reducing unwanted reflection of a light

source.

6. A film according to Claim 5, wherein the AR coat includes nanometric

particles of inorganics in an organic matrix which permits some degree of

stretch deformation.

7. A film according to Claim 6, wherein the organic matrix includes

polysiloxane compounds.

8. A film according to Claim 7, wherein the AR coat comprises a layer

containing titanium compounds sandwiched between two layers

containing polysiloxanes which are substantially titanium free.

9. A film according to Claim 8, wherein the layer proximate to the film substrate contains polysiloxane resins, colloidal silica, organic

dicarboxylic acid and surfactants.

10. A film according to any one of Claims 1 to 4, wherein the optically

effective coat confers the effect of a sunlens, a tinted lens, a mirror

coated lens, or any combination of these effects.

11. A film according to any one of Claims 1 to 10, further including a hard

coat sandwiched between the film substrate and the optically effective

coat.

12. A film according to Claim 11 , wherein the hard coat comprises an

inorganic compound linked to an organic matrix.

13. A film according to Claim 12, wherein the organic matrix in the hard coat

includes a polysiloxane.

14. A film according to any one of Claims 1 to 13, further including a

lubricious organic coating applied to the optically effective coat.

15. A film according to any one of Claims 11 to 14, wherein the optically

effective coat is applied by liquid film application techniques and the hard

coat is applied by liquid film application techniques.

16. A film according to Claim 15, wherein the optically effective coat and the

hard coat are applied by dip coating, roller coating, or spin coating.

17. A film according to any one of Claims 11 to 14, wherein the optically

effective coat is applied by vacuum deposition techniques and the hard

coat is also applied by vacuum deposition techniques and wherein the

vacuum applied hard coat and optically effective coat each include

organic material which render them extensible without cracking.

18. A light transmitting article including, an article substrate, and a film

applied to the article substrate, the film including a film substrate and an optically effective coat applied to the film substrate.

19. A light transmitting article according to Claim 18, wherein the light

transmitting article is an ophthalmic lens having front and rear surfaces.

20. A light transmitting article according to Claim 19 wherein said film is applied to at least the rear surface of the lens.

21. A light transmitting article according to Claim 20, wherein said film is

applied to both said front and rear surfaces of the lens.

22. A light transmitting article according to Claim 19, wherein the film is

adhered to the surface of the lens by means of a UV curable adhesive.

23. A light transmitting article according to any one of Claims 18 to 22,

wherein the film is in accordance with any one of Claims 2 to 17.

24. Apparatus for laminating a film to an ophthalmic lens, including means

for drawing the film tautly across a flat or substantially convex surface of

the lens such that it conformingly engages the surface of the lens.

25. Apparatus according to Claim 24, wherein said means for drawing the

film across the surface of the lens comprises a pair of laminating rings.

26. Apparatus according to Claim 24 or Claim 25, further including a film

deforming member for urging the film into conforming engagement with a

substantially concave surface of the lens.

27. Apparatus according to Claim 26, wherein said film deforming member

includes a bladder having a flexible wall which conformingly engages the

concave surface of the lens when the bladder is filled with fluid under

pressure.

28. Apparatus according to any one of Claims 24 to 27, further including a

UV source for irradiating the lens with UV radiation so as to cure a UV

curable adhesive for adhering the film to the lens./