# US 10,503,016 B2 · Liquid crystal display device, polarizer and protective film

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- Number: US 10,503,016 B2
- Document ID: US10503016B2
- Status: Granted
- Kind: B2
- Application number: 15/861,186
- Filed: 2018-01-03
- Published: 2018-06-21
- Granted: 2019-12-10
- Earliest claimed: 2010-06-22
- Assignees: Toyobo Co., Ltd.
- Applicants: Toyobo Co., Ltd.
- Inventors: Koichi Murata; Yasushi Sasaki
- Web page: https://patentgrep.com/patent/US10503016B2

## CPC

- G02F 1/13363: Birefringent elements, e.g. for optical compensation
- G02B 5/3083: {Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001)}
- G02F 1/133528: {Polarisers}
- G02F 1/1336: {Illuminating devices}
- G02F 1/13362: {providing polarized light, e.g. by converting a polarisation component into another one}
- G02B 1/14: Protective coatings, e.g. hard coatings
- G02B 5/3033: {in the form of a thin sheet or foil, e.g. Polaroid}
- G02F 1/133562: {on the viewer side}
- G02F 1/133567: {on the back side}
- G02F 1/133624: {characterised by their spectral emissions}
- G02F 2201/50: Protective arrangements
- G02F 2202/40: Materials having a particular birefringence, retardation
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

Provided is a liquid crystal display device that has excellent visibility while using a protective film comprising a polyester film. The liquid crystal display device comprises a backlight light source, and a liquid crystal cell disposed between two polarizers; the backlight light source being a white light-emitting diode; each of the polarizers comprising a polarizing film and protective films laminated on both sides of the polarizing film; and at least one of the protective films being a polyester film having a retardation of 3,000 to 30,000 nm.

## Claims

### Claim 1

A display device comprising a first polarizer, a liquid crystal cell, a second polarizer, and a backlight source, wherein
the liquid crystal cell has a light-outgoing side and a light-incoming side,
the first polarizer is disposed on the light-outgoing side of the liquid crystal cell,
the first polarizer comprises (a) a first polarizing film and (b) a first protective film laminated on the light-outgoing side of the first polarizing film,
the second polarizer is disposed on the light-incoming side of the liquid crystal cell,
the second polarizer comprises (a) a second polarizing film and (b) a second protective film laminated on the light-incoming side of the second polarizing film,
the first protective film optionally is an oriented film having an in-plane retardation of 3,215 nm or more and less than 10,000 nm and a ratio of in-plane retardation to thickness-direction retardation (Re/Rth) of 0.5 to 2.0,
the second protective film is an oriented film having an in-plane retardation of 3,215 nm or more and less than 10,000 nm and a ratio of in-plane retardation to thickness-direction retardation (Re/Rth) of 0.5 to 2.0, and
no oriented film having an in-plane retardation of 3,215 to 30,000 nm is disposed between the light-incoming side of the first polarizing film and the light-outgoing side of the second polarizing film.

### Claim 2 (depends on 1)

The display device of claim 1, wherein the first protective film is an oriented film having an in-plane retardation of 3,215 nm or more and less than 10,000 nm and a ratio of in-plane retardation to thickness-direction retardation (Re/Rth) of 0.5 to 2.0.

### Claim 3 (depends on 2)

The display device of claim 2, wherein the first protective film that is an oriented film having an in-plane retardation of 3,215 nm or more and less than 10,000 nm and a ratio of in-plane retardation to thickness-direction retardation (Re/Rth) of 0.5 to 2.0 is a polyester film.

### Claim 4 (depends on 1)

The display device of claim 1, wherein the second protective film that is an oriented film having an in-plane retardation of 3,215 nm or more and less than 10,000 nm and a ratio of in-plane retardation to thickness-direction retardation (Re/Rth) of 0.5 to 2.0 is a polyester film.

### Claim 5 (depends on 1)

The display device of claim 1, wherein the first protective film is not an oriented film having an in-plane retardation of 3,215 nm or more and less than 10,000 nm and a ratio of in-plane retardation to thickness-direction retardation (Re/Rth) of 0.5 to 2.0 and is a triacetyl cellulose film, an acrylic film, or a norbornene film.

### Claim 6 (depends on 1)

The display device of claim 1, wherein the first protective film is not an oriented film having an in-plane retardation of 3,215 nm or more and less than 10,000 nm and a ratio of in-plane retardation to thickness-direction retardation (Re/Rth) of 0.5 to 2.0 and is a birefringence-free film.