# US 7,746,433 B2 · Liquid crystal display and electronic apparatus

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- Number: US 7,746,433 B2
- Document ID: US7746433B2
- Status: Granted
- Kind: B2
- Application number: 12/107,952
- Filed: 2008-04-23
- Published: 2008-12-25
- Granted: 2010-06-29
- Earliest claimed: 2007-05-01
- Assignees: Epson Imaging Devices Corporation
- Inventors: Hiroshi Wada
- Web page: https://patentgrep.com/patent/US7746433B2

## CPC

- G02F 1/133555: {Transflectors}
- G02F 1/133631: {with a spatial distribution of the retardation value}
- G02F 1/133638: {Waveplates, i.e. plates with a retardation value of lambda/n}
- G02F 1/134363: {for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]}
- G02F 2203/60: Temperature independent
- 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

## Abstract

A liquid crystal display includes an element substrate, pixel electrodes and a common electrode that are formed on the element substrate, a counter substrate, a liquid crystal layer that is formed between the counter substrate and the element substrate, first and second polarizing plates that are provided on an emitting side of display light and an opposite side, respectively, and a retardation film that is provided in a reflective region to be disposed between the liquid crystal layer and the first polarizing plate. Each pixel has a transmissive region where transmissive display light is emitted and a reflective region where reflective display light is emitted. The retardation of the retardation film has smaller temperature dependency than the retardation of the liquid crystal layer.

## Claims

### Claim 1

A liquid crystal display, comprising:
an element substrate;
a pixel electrode that is formed at each pixel of the element substrate;
a common electrode that is formed on the element substrate, an electric field being formed between the pixel electrodes and the common electrode;
a counter substrate that is arranged to face the element substrate;
a liquid crystal layer that is formed between the counter substrate and the element substrate;
first and second polarizing plates that are provided on an emitting side of display light passing through the liquid crystal layer and an opposite side, respectively; and
a retardation film that is disposed between the liquid crystal layer and the first polarizing plate, wherein:
the pixel has a transmissive region where transmissive display light is emitted and a reflective region where reflective display light is emitted;
the retardation of the retardation film has smaller temperature dependency than that of the liquid crystal layer; and
one of the pixel electrode and the common electrode is formed on the element substrate facing the liquid crystal layer, and has a plurality of slit-shaped openings, which are formed within each region of the pixel at predetermined intervals.

### Claim 2 (depends on 1)

The liquid crystal display according to claim 1,
wherein the counter substrate is arranged on the emitting side of display light, and
the retardation film is formed on a surface of the counter substrate facing the liquid crystal layer.

### Claim 3 (depends on 1)

The liquid crystal display according to claim 1,
wherein, in the reflective region, a light reflecting layer is formed on a surface of the element substrate facing the liquid crystal layer, and
the retardation film is formed to overlap the light reflecting layer in plan view.

### Claim 4 (depends on 1)

The liquid crystal display according to claim 1,
wherein the pixel electrode is formed closer to the liquid crystal layer than the common electrode.

### Claim 5 (depends on 1)

The liquid crystal display according to claim 1,
wherein the common electrode is formed closer to the liquid crystal layer than the pixel electrode.

### Claim 6 (depends on 1)

The liquid crystal display according to claim 1,
wherein the pixel electrode and the common electrode are formed in the same layer in the element substrate and have a comb shape, and the tooth portions of the comb shape are arranged in alternate relationship to face each other.

### Claim 7 (depends on 1)

An electronic apparatus comprising the liquid crystal display according to claim 1.

### Claim 8 (depends on 1)

The liquid crystal display according to claim 1,
wherein the retardation film is formed of a liquid crystal polymer, and the retardation of the retardation film is set at a ½ wavelength.

### Claim 9 (depends on 1)

The liquid crystal display according to claim 1,
wherein the retardation film is formed of a liquid crystal polymer, and a nematic phase transition temperature of the liquid crystal polymer is 130° C.