Liquid crystal display and electronic apparatus having a quasi-isotropic liquid crystal material

• US 7,420,635 B2
• Filed: 12/09/2005
• Issued: 09/02/2008
• 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
• Primary Examiner(s): QI, ZHI QIANG
• Application Number:
  US11/297,347
• Publication Number:
  US 20060170846A1
• Time in Patent Office: 998 Days
• Field of Search: 349/114, 349/141, 349/2, 349/84
• 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 to the first substrate; and

a liquid crystal layer formed between the first and the second substrate, the liquid crystal layer including a quasi-isotropic liquid crystal material, the quasi-isotropic liquid crystal material being optically isotropic when an non-selected electric field is applied and being optically anisotropic when the selected electric field is applied, a flexibility of the quasi-isotropic liquid crystal material being changed according to an selected electric field intensity, the selected electric field intensity of the liquid crystal layer on the reflecting portion being smaller than the selected electric field intensity of the liquid crystal layer on the transparent portion.

2. The liquid crystal display according to claim 1, each of the reflecting portion and the transparent portion having at least a pixel electrode and at least a common electrode, the selected electric field being applied between the pixel electrode and the common electrode.

3. The liquid crystal display according to claim 1, 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 of the first pixel electrode and the first common electrode being different from a distance of the second pixel electrode and the second common electrode.

4. 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 of the first pixel electrode and the first common electrode being smaller than a distance of 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

/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 of the first pixel electrode and the first common electrode being larger than a distance of the second pixel electrode and the second common electrode.

6. The liquid crystal display according to claim 1, wherein the substrates have an almost flat surface on the side facing to the liquid crystal layer.

7. 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.

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 low molecular weight liquid crystal material having a blue phase between a cholesteric phase and an isotropic phase.

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 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.

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