JPH03157617A - Production of liquid crystal lens - Google Patents

Abstract

PURPOSE:To obtain the lens which is resistant to flaw by laminating transparent polycarbonate sheets via adhesive on both surfaces of a variable focus liquid crystal lens, pressing the sheet by molds and thereby molding the sheet into a lens shape. CONSTITUTION:A photosetting adhesive 12 consisting of 26 pts. wt. compd. of formula I, 70 pts. wt. 2-hydroxy-3-phenoxy propyl acrylate, 2 pts. wt. 2, 4-diethyl thioxantone, and 2 pts. wt. p-N,N-dimethyl amino ethyl benzoate is applied by a knife on the transparent polycarbonate sheet 13, exclusive of 0.5mm at the periphery, to form the adhesive layer 12 of 20 mum thickness. The sheet is imposed on a polyethylene sheet 1 in such a manner that the adhesive layer 12 faces upward. The flat plate variable focus liquid crystal lens 11 is placed thereon and the transparent polycarbonate sheet 13 with the adhesive layer 12 faced downward is placed thereon. The mold 4 is moved downward and the assembly is pressed by the molds 3 and 4. The assembly is then exposed with a high-pressure mercury lamp and thereafter, the sheet 1 is peeled to obtain the liquid crystal lens. The sagging and flowing of the adhesive 12 from the ends are obviated in this way. Bubbles do not enter the adhesive layers 12 and the lens having the surface which has the high hardness and is resistant to flaw is obtd.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for manufacturing a liquid crystal lens.

(Prior art) When the crystalline lens of the eyeball is removed due to an eye disease such as cataract, it is not possible to use conventional fixed focal length lenses as glasses. It is very inconvenient in real life, as you have to keep it in mind and use it depending on the situation. For this reason, various liquid crystal lenses whose focal lengths can be electrically varied have recently been proposed. (For example, JP-A-61-13892
(No. 2, Japanese Patent Application Laid-open No. 62-47026) Furthermore, since it is difficult to manufacture liquid crystal lenses from glass and is heavy, synthetic resin conductive films have been proposed as a countermeasure to this problem. Japanese Patent Publication No. 61-2467
No. 19 discloses that a polyether sulfone film (hereinafter referred to as PES) or a polysulfone film is adhered to both sides of a polarizing film, a transparent conductive film is laminated on one side, and a photocurable resin coating layer is laminated on the other side. A transparent conductive film integrated with a polarizing film is described, and by laminating this film and a liquid crystal layer, a lightweight liquid crystal lens can be obtained.

However, this liquid crystal lens has the disadvantage that the surface is coated with a photocurable resin coating layer, and the surface condition is poor, the surface hardness is low, and it is difficult to shape into a lens shape.

Furthermore, there is a drawback that water enters from the edges of the liquid crystal lens, resulting in a decrease in liquid crystallinity.

(Problems to be Solved by the Invention) In view of the above-mentioned drawbacks, an object of the present invention is to easily manufacture a liquid crystal lens that has a high surface hardness, is hard to be scratched, and has a good surface condition, and a liquid crystal lens that has excellent water-resistant sealing properties. The purpose is to provide a method.

(Means for Solving the Invention) The variable focus liquid crystal lens used in the present invention can be any conventional variable focus liquid crystal lens as long as it has a liquid crystal layer and a conductive layer for applying a voltage to the liquid crystal layer. For example, a variable focus device in which ITO vapor deposited conductive layers are laminated on both sides of a liquid crystal layer, and polarizing films with PES films adhered to both sides of the liquid crystal layer are laminated on both sides of the vapor deposited layers. Liquid crystal lenses are available.

The polycarbonate sheet used in the present invention only needs to be transparent, but the thicker it becomes, the more difficult it is to shape.
A thickness of m to lam is preferred.

In the present invention, since the variable focus liquid crystal lens and the transparent polycarbonate sheet are bonded together with an adhesive, the adhesive is preferably transparent and of a photocurable type.
For example, adhesives mainly composed of acrylate oligomers such as epoxy acrylate, urethane acrylate, and polyester acrylate, to which meth)acrylate monomers, sensitizers, and the like are added are preferably used. In addition, it is preferable that the adhesive becomes uniform when pressed and that excess adhesive flows out from the edges, so the viscosity should be 200 to 2000 c.
ps is preferred.

The molds used in the present invention include a mold having a lens-shaped concave mating surface and a mold having a convex mating surface.

This mold can be made of any material, but when a photocurable adhesive is used as the adhesive, it is preferably made of a highly transparent material such as polycarbonate, polymethyl methacrylate, or glass.

In addition, the size of the mold is such that the length and length of the mold are such that if the adhesive is squeezed out when pressed, it can be wiped off, that is, the end of the laminate can be pushed out of the mold. It is preferable that the width is about 1 to 2 w narrower than that of the laminate.

In the present invention, a laminate in which transparent polycarbonate sheets with a wider area than the liquid crystal lens are laminated on both sides of the variable focus liquid crystal lens via an adhesive is pressed with a mold, and the laminate is bonded with the adhesive and formed into a lens shape. Shape.

The width of the polycarbonate sheet should be wider than the liquid crystal lens, but it is preferably wide enough that when laminated, the periphery of each sheet protrudes by 0.2 to 51 cm.

The variable focus liquid crystal lens and the transparent polycarbonate sheet may be supplied to the mold as a laminate, but the polycarbonate sheet with the adhesive layer formed is supplied first, then the variable focus liquid crystal lens is placed on top of it, and then Volica with an adhesive layer formed on top.

- Bonate sheets may be stacked, and in this case, an adhesive layer may be formed on the variable focus liquid crystal lens.

The thickness of the adhesive layer should be set at 4:00 because when the amount of adhesive increases, the excess adhesive will be pushed out from the edges by pressure.
~100 μm is preferable, and in this case, it is preferable that the lower mold has a concave mating surface so that air is not trapped in the adhesive layer.

The pressure of the mold may be as long as the above-mentioned laminate is bonded and shaped, but generally the pressure is 0.1 to 1. It is preferable to press at 0 kg/d for 1 to 3 minutes, and heating may be performed within a range that does not adversely affect the liquid crystal lens.

Also, in order to prevent the extruded adhesive from dripping during shaping, a sheet with a wider area than the polycarbonate sheet may be laminated on both sides of the laminate. This sheet may be made of polyethylene, polypropylene, etc. It is preferable to use a transparent and flexible sheet having a thickness of 5 to 30 .mu.m, and preferably a size in which both ends protrude by at least 1 .mu.m from the polycarbonate sheet.

After the adhesive hardens, the mold is loosened and the laminate is taken out to obtain a shaped liquid crystal lens.

In the second aspect of the invention, the adhesive layer is also made to have a wider area than the liquid crystal lens, and is laminated and bonded.

The adhesive layer only needs to be about 0.2 to 1.01 wider around the periphery than the liquid crystal lens, and as a result, a hardened layer of adhesive is formed around the outer periphery of the liquid crystal lens, improving the water-resistant sealing properties of the liquid crystal lens. improves.

(Example) Next, an example of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an example of an apparatus for manufacturing a liquid crystal lens. 2 in the figure is a substantially U-shaped frame, and a mold 3 with a concave mating surface 31 facing upward, A mold 4, which is installed at the bottom of the frame l and has a convex mating surface 41 facing downward, is installed at the top of the frame l. The mold 4 is installed in the frame 1 so as to be slidable up and down, and can be pressurized from above to below.

A 20 μm thick polyethylene sheet was placed on the concave mating surface 31 of the mold 3.

General formula H-(QC!)1.0OCC4HICO), -
0CJ400CN)l-C&H44HCO-(OCJa
OOCCJsCO)--OCtHaOH(Mw=160
26 parts by weight of a compound represented by 001Mn・9000),
The photocurable adhesive side made of 70 parts by weight of 2-hydroxy-3-phenoxypropyl acrylate, 2 parts by weight of 2,4-diethylthioxanthone, and 2 parts by weight of ethyl p-N,N-dimethylaminobenzoate was bonded to a thickness of 0. Leave 0.5s+m around the .5mm transparent polycarbonate sheet.
It was applied with a doctor knife to form an adhesive layer with a thickness of 20 μm, and placed on the polyethylene sheet with the adhesive layer facing upward. Gently place a flat variable focus liquid crystal lens on top of it, then place a transparent polycarbonate sheet laminated with an adhesive layer created in the same manner as above on top of the variable focus liquid crystal lens with the adhesive layer facing down. placed. Further, a polyethylene sheet having a thickness of 20 μm was placed on top of the film. The variable focus liquid crystal lens has ITO vapor deposited conductive layers laminated on both sides of the liquid crystal layer, and PES on both sides.
It had a thickness of 0.5 m and consisted of a polarizing film to which a film was adhered and laminated on both sides of the vapor deposited layer. Also, the polycarbonate sheet has a thickness of about 0.0mm from the liquid crystal lens to the surrounding area.
The polyethylene film protruded by 15 mm from the polycarbonate sheet to the surrounding area.

Next, move mold 4 downward, and molds 3 and 4 weigh 0.5 kg/-
Pressed with pressure. It was pressed for 1 minute, and then illuminated with 1000 sJ/c4n from a high-pressure mercury lamp on the third day. After exposure, the laminate is taken out and the polyethylene sheet is peeled off to a thickness of 1.6-
A lenticular liquid crystal lens was obtained. Note that the adhesive did not drip or fall from the end.

FIG. 2 is a partially enlarged sectional view of the obtained liquid crystal lens.
In the figure, 11 is a variable focus liquid crystal lens, 12.12 is a photocured adhesive layer laminated on both sides of the variable focus liquid crystal lens 11, and 13.13 is a varifocal liquid crystal lens 11 attached to the variable focus liquid crystal lens 11 by the adhesive layer 12. This is a transparent polycarbonate sheet that is wider than the liquid crystal lens 11 and is glued thereto.

FIG. 3 is a partially enlarged sectional view of a liquid crystal lens obtained in the same manner as in the above example except that adhesive was applied to the entire surface of the polycarbonate sheet. ', 12'' are photo-cured adhesive layers laminated on both sides of the variable focus liquid crystal lens 11°,
They are bonded and hardened at the 11° edge of the liquid crystal lens. 1
3', 13° is a transparent polycarbonate sheet that is wider than the liquid crystal lens 11' and is adhered to the variable focus liquid crystal lens 11' by an adhesive layer 12'.

(Effects of the Invention) Since the method for manufacturing a liquid crystal lens of the present invention is as described above, no air bubbles are introduced into the adhesive layer, and the adhesive is not extruded from the periphery of the laminate, or even if it is extruded, the polycarbonate sheet remains intact. The receiver is fixed and does not stick to the mold, making it easy to manufacture.The surface of the obtained liquid crystal lens is highly hard and scratch resistant, and the surface condition is good, making it suitable for use as a variable focus liquid crystal lens. used for.

Furthermore, the second invention has even better water-resistant sealing properties and is more suitably used as a variable focus liquid crystal lens.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of an apparatus for manufacturing a liquid crystal lens, and FIGS. 2 and 3 are partially enlarged sectional views showing an example of a liquid crystal lens manufactured by the present invention.

Claims (1)

[Claims] 1. A transparent polycarbonate sheet having a wider area than the liquid crystal lens is laminated on both sides of a variable focus liquid crystal lens having a liquid crystal layer and a conductive layer for applying voltage to the liquid crystal layer via an adhesive. A liquid crystal lens characterized in that the laminate is pressed between a mold having a concave mating surface and a mold having a convex mating surface, and the laminate is bonded with the adhesive and shaped into a lens shape. Production method. 2. A transparent polycarbonate sheet with a wider area than the liquid crystal lens is attached to the screen of the variable focus liquid crystal lens, which has a liquid crystal layer and a conductive layer for applying voltage to the liquid crystal layer, via an adhesive layer that is wider than the liquid crystal lens. A liquid crystal lens characterized in that a stacked laminate is pressed between a mold having a concave mating surface and a mold having a convex mating surface, and the laminate is bonded with the adhesive and shaped into a lens shape. manufacturing method.