Liquid crystal display and electronic apparatus

• US 20080316403A1
• Filed: 07/17/2008
• Published: 12/25/2008
• Est. Priority Date: 02/03/2005
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Ozawa, Kinya
• Granted Patent: US 7,639,327 B2
• Time in Patent Office: Days
• US Class Current: 349/114
• CPC Class Codes: G02F 1/13345 Network or three-dimensional gels
• CPC Class Codes: G02F 1/133555 Transflectors
• 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 transflective liquid crystal display that includes a liquid crystal layer interposed between a pair of substrates facing each other and a transparent display area for transparent display and a reflecting display area for reflecting display within a single pixel area, wherein the liquid crystal layer is composed of a quasi-isotropic liquid crystal material that is optically isotropic when non-selected electric field is applied and is optically anisotropic when selected electric field is applied, the flexibility of which changing according to the electric field intensity, and the electric field intensity is supposed to be set smaller in the reflecting display area than in the transparent display area.

Claims

1. A liquid crystal display, comprising:

a first substrate having a reflecting portion and a transparent portion;

a second substrate facing the first substrate; and

a liquid crystal layer formed between the first and the second substrates, the liquid crystal layer including a quasi-isotropic liquid crystal material, the quasi-isotropic liquid crystal material being optically isotropic when a non-selected electric field is applied and being optically anisotropic when the selected electric field is applied, a refractive index of the quasi-isotropic liquid crystal material being changed according to a selected electric field intensity, the refractive index under the selected electric field in the reflecting portion being different from the refractive index under the selected electric field in the transparent portion.

2. The liquid crystal display according to claim 1, the selected electric field being applied substantially parallel to a plane of the first substrate or to a plane of the second substrate.

3. The liquid crystal display according to claim 1, one of the first substrate and the second substrate having a pixel electrode and a common electrode in each of the reflecting portion and the transparent portion, the selected electric field being applied between the pixel electrode and the common electrode.

4. The liquid crystal display according to claim 1, one of the first substrate and the second substrate having a first pixel electrode and a first common electrode in each of the reflecting portions, and a second pixel electrode and a second common electrode in each of the transparent portions, a distance between the first pixel electrode and the first common electrode being different from a distance between the second pixel electrode and the second common electrode.

5. The liquid crystal display according to claim 1, a phase contrast Δ

nd of the liquid crystal layer being λ

/2, the reflecting portion having a first pixel electrode and a first common electrode, the transparent portion having a second pixel electrode and a second common electrode, a distance between the first pixel electrode and the first common electrode being smaller than a distance between the second pixel electrode and the second common electrode.

6. The liquid crystal display according to claim 1, a phase contrast Δ

nd of the liquid crystal layer being λ

/4, the reflecting portion having a first pixel electrode and a first common electrode, the transparent portion having a second pixel electrode and a second common electrode, a distance between the first pixel electrode and the first common electrode being larger than a distance between the second pixel electrode and the second common electrode.

7. The liquid crystal display according to claim 1, wherein the substrates have a substantially flat surface on the side facing the liquid crystal layer.

8. The liquid crystal display according to claim 1, the quasi-isotropic liquid crystal material including a low molecular weight liquid crystal material and a polymer network, the polymer network being formed by a polymerization of a non-liquid crystal monomer.

9. The liquid crystal display according to claim 1, the quasi-isotropic liquid crystal material including a low molecular weight liquid crystal material and a polymer network, the low molecular weight liquid crystal material having a blue phase between a cholesteric phase and an isotropic phase.

10. The liquid crystal display according to claim 1, the quasi-isotropic liquid crystal material including a low molecular weight liquid crystal material and a polymer network, the polymer network being formed by a polymerization of a non-liquid crystal monomer, the non-liquid crystal monomer being an acrylate monomer that has an alkyl group as a side chain.

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