# US 5,344,513 A · Method of manufacturing laminated transparent substrate having birefringence

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- Number: US 5,344,513 A
- Document ID: US5344513A
- Status: Granted
- Kind: A
- Application number: 08/071,040
- Filed: 1993-06-01
- Granted: 1994-09-06
- Earliest claimed: 1990-08-28
- Assignees: Stanley Electric Co., Ltd.
- Inventors: Shunji Takenaka
- Web page: https://patentgrep.com/patent/US5344513A

## CPC

- B32B 17/1099: {After-treatment of the layered product, e.g. cooling}
- B32B 17/10036: {comprising two outer glass sheets}
- B32B 17/10743: {containing acrylate (co)polymers or salts thereof}
- B32B 17/10853: {the membrane being bag-shaped}
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM

## Abstract

A method of manufacturing a laminated transparent substrate comprising the steps of sandwiching between transparent glass substrates ionomer resin formed by bridging ethylenemetacryl acid copolymars with sodium ions, to form a laminated structure and sealing it in a reduced pressure atmosphere; applying heat and pressure to said laminated structure; rapidly decreasing the pressure applied to said laminated structure; and then rapidly decreasing the temperature of said laminated structure.

## Claims

### Claim 1

A method of manufacturing an optical compensator having a negative anisotropy comprising the successive steps of:
(a) sandwiching between a pair of transparent substrates an ionomer resin, to form an optical compensator having a negative anisotropy and sealing it in a reduced pressure atmosphere;
(b) applying heat to and increasing the pressure on said optical compensator;
(c) while maintaining said optical compensator at a high temperature rapidly decreasing the pressure applied to said optical compensator; and thereafter
(d) quenching and rapidly decreasing the temperature of said optical compensator thereby providing negative anisotropy to said optical compensator.

### Claim 2 (depends on 1)

The method of manufacturing an optical compensator having a negative anisotropy according to claim 1, wherein said ionomer resin is formed by bridging ethylene metacryl acid copolymers with metal ions.

### Claim 3 (depends on 2)

The method of manufacturing an optical compensator having a negative anisotropy according to claim 2, wherein said ionomer resin contains sodium ions.

### Claim 4 (depends on 1)

The method of manufacturing an optical compensator having a negative anisotropy according to claim 1, wherein the heat and the increase in pressure applied to step (b) are conducted in an autoclave.

### Claim 5 (depends on 4)

The method of manufacturing an optical compensator having a negative anisotropy according to claim 4, wherein the step of rapid quenching the optical compensator is achieved by removing the optical compensator from the autoclave and placing it in a low temperature furnace.

### Claim 6 (depends on 1)

The method of manufacturing an optical compensator having a negative anisotropy according to claim 1, wherein step (b) raises the temperature of the substrate to 100-150.degree. C.

### Claim 7 (depends on 1)

The method of manufacturing an optical compensator having a negative anisotropy according to claim 1, wherein step (b) increases the pressure to 1-5 atms.