Liquid crystal display device and electronic apparatus

• US 20060203169A1
• Filed: 01/17/2006
• Published: 09/14/2006
• Est. Priority Date: 02/28/2005
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Ozawa, Kinya, Shimamura, Hideo
• Granted Patent: US 7,843,540 B2
• Time in Patent Office: Days
• US Class Current: 349/141
• CPC Class Codes: G02F 1/133541 Circular polarisers
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/13731 based on a field-induced phase transition G02F1/13781 takes precedence
• CPC Class Codes: G02F 1/13775 Polymer-stabilized liquid crystal layers
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence

Abstract

A liquid crystal display device of the present invention is a liquid crystal display device having a first substrate, a second substrate, a liquid crystal layer disposed between the first and second substrates, and a plurality of pixels each having a display region, in that: the liquid crystal layer is optically isotropic when an selective electric field is not applied and optically aisotropic when an electric field is applied and includes a material whose refractive index changes depending on the strength of the electric field; and the plurality of pixels include first and second pixels different in the electric field strength.

Claims

1. A liquid crystal display device, comprising:

a first substrate;

a second substrate;

a liquid crystal layer disposed between the first and second substrates, the liquid crystal layer being optically isotropic when an selective electric field is not applied, the liquid crystal layer being optically aisotropic when an electric field is applied, a refractive index of a material of the liquid crystal layer being changed depending on a strength of an electric field;

a first pixel formed on the first substrate, the first pixel having an first electric field strength; and

a second pixel formed on the first substrate, the second pixel having an second electric field strength, the first electric field strength and the second electric field strength being different.

3. The liquid crystal display device according to claim 1, the first pixel displaying a first color, the second pixel displaying a second color, the first color and the second color being different.

4. The liquid crystal display device according to claim 3, at least a first portion of the liquid crystal layer being overlapped with the first pixel, at least a second portion of the liquid crystal layer being overlapped with the second pixel, the first portion and the second portion having different refractive indexes.

7. The liquid crystal display device according to claim 1, further comprising:

a reflective film formed between the first substrate and the liquid crystal layer, a portion of the liquid crystal layer being overlapped with the reflective film, the part of the liquid crystal layer having a optical phase difference Δ

nd, the optical phase difference Δ

nd being approximately λ

/4.

8. The liquid crystal display device according to claim 1, a portion of the liquid crystal layer having a optical phase difference Δ

nd, the optical phase difference Δ

nd being approximately λ

/2.

9. The liquid crystal display device according to claim 1, the liquid crystal layer including a pseudo-isotropic liquid crystal.

10. The liquid crystal display device according to claim 1, the liquid crystal layer including a composite liquid crystal composition, the composite liquid crystal composition including a low molecule liquid crystal material and a polymer network, the polymer network being formed among constituent molecules of the low molecule liquid crystal material, and the polymer network being formed by polymerizing non liquid crystal monomers.

11. The liquid crystal display device according to claim 10, the low molecule liquid crystal material having a blue phase between a cholesteric phase and an isotropic phase.

12. The liquid crystal display device according to claim 10, the non liquid crystal monomer being an acrylate-based monomer that has an alkyl group as the side chain.

13. An electronic apparatus including the liquid crystal display device according to claim 1.

2. A liquid crystal display device, comprising:

a first substrate having a plurality of pixels, each of the pixels having at least a pixel electrode and a common electrode;

a second substrate;

a liquid crystal layer disposed between the first and second substrates, the liquid crystal layer being optically aisotropic when a voltage is applied between the pixel electrode and the common electrode, the liquid crystal layer being optically isotropic when a voltage is not applied between the pixel electrode and the common electrode, a refractive index of a material of the liquid crystal layer being changed depending on a voltage strength;

a first pixel formed on the first substrate, the first pixel displaying a first color, the first pixel having at least a first pixel electrode and at least a first common electrode, the first pixel having a first distance between the first pixel electrode and the common electrode; and

a second pixel formed on the first substrate, the second pixel displaying a second color, the second pixel having at least a second pixel electrode and at least a second common electrode, the second pixel having a second distance between the second electrode and the second common electrode, the first distance and the second distance being different.

5. The liquid crystal display device according to claim 2, a first portion of the liquid crystal layer being overlapped with the first pixel, a first light of a first wavelength being modulated by the first portion, a second portion of the liquid crystal layer being overlapped with the second pixel, a second light of a second wavelength being modulated by the second portion, the first distance being larger than the second distance, the first wavelength being shorter than the second wavelength.

6. The liquid crystal display device according to claim 5, the first color being blue and the second color being green.