Liquid crystal device

• US 5,831,705 A
• Filed: 04/28/1997
• Issued: 11/03/1998
• Est. Priority Date: 08/04/1994
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kaneko, Shuzo, Kojima, Makoto, Kishi, Etsuro, Gofuku, Ihachiro, Nakamura, Katsutoshi
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Dudek, James A.
• Application Number:
  US08/846,179
• Time in Patent Office: 554 Days
• Field of Search: 349/133, 349/135, 349/138, 349/122, 349/128
• US Class Current: 349/128
• CPC Class Codes: G02F 1/133397 for suppressing after-image or image-sticking
• CPC Class Codes: G02F 1/1337 Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
• CPC Class Codes: G02F 1/133711 by organic films, e.g. polymeric films
• CPC Class Codes: G02F 1/133719 with coupling agent molecules, e.g. silane
• CPC Class Codes: G02F 1/133723 Polyimide, polyamide-imide
• CPC Class Codes: G02F 1/141 using ferroelectric liquid crystals

Abstract

A liquid crystal device is constituted by a pair of oppositely disposed substrates including a first substrate having a uniaxial alignment characteristic and a second substrate having a non-uniaxial alignment characteristic and a liquid crystal disposed between the first and second substrates. The first and second substrates are controlled to have surface potentials providing a difference therebetween of less than 50 mV in terms of an absolute value at their liquid crystal-contacting surfaces. As a result, the liquid crystal device is provided with an improved symmetry of switching threshold while retaining a good liquid crystal alignment characteristic.

Claims

1. A liquid crystal device, comprising:

a pair of oppositely disposed substrates, and a liquid crystal disposed between the substrates, one of the substrates having a uniaxial alignment characteristic, and the other substrate having a non-uniaxial alignment characteristic,

wherein the substrate having a non-uniaxial alignment characteristic has a film with a volume resistivity of 10⁴ -10⁸ ohm·

cm in the film thickness direction and a volume resistivity of 10⁶ -10⁹ ohm.cm in the film extension direction, thus exhibiting a resistivity anisotropy between the film thickness direction and the film extension direction.

2. A liquid crystal device according to claim 1, wherein said film exhibiting a resistivity anisotropy comprises a film formed by wet coating.

3. A liquid crystal device according to claim 1, wherein said film exhibiting a resistivity anisotropy comprises a matrix material having dispersed therein electroconductive particles with a particle size of 30-300 Å

.

4. A liquid crystal device according to claim 3, wherein said fine particles are doped with an electroconductivity-controlling impurity.

5. A liquid crystal device according to claim 1, wherein said liquid crystal is a chiral smectic liquid crystal.

6. A liquid crystal device according to claim 1, wherein said liquid crystal has a phase transition series of isotropic phase, smectic A phase and chiral smectic phase on temperature decrease.