Field effect mode liquid crystal display

• US 4,521,080 A
• Filed: 10/18/1982
• Issued: 06/04/1985
• Est. Priority Date: 07/01/1974
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Shimizu, Keiichiro, Funada, Fumiaki
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/432,660
• Time in Patent Office: 960 Days
• Field of Search: 350/334, 350/341
• US Class Current: 349/129
• CPC Class Codes: G02F 1/13378 by treatment of the surface, e.g. embossing, rubbing or light irradiation G02F1/133711, G02F1/133734, G02F1/133753 take precedence
• CPC Class Codes: G02F 1/133784 by rubbing

Abstract

A nematic-phase liquid crystal material is sandwiched between two opposing parallel plates at least one of which is transparent. The two parallel plates are respectively coated with transparent electrode films having parallel micro-groove structures at the respective inner surfaces in contact with the nematic-phase liquid crystal material established by unidirectional rubbing. In particular, an additional or second micro-groove structure is further provided for said fist-named micro-groove structure which has an asymmetric or anisotropic profile along the longitudinal axes of the respective micro-grooves within the first micro-groove structure, preferably of a substantially saw-tooth profile. This combination results in a surface anisotropy in solid geometry rather than in plane geometry in the interfacial surfaces. The surface anisotropies in the two interfacial surfaces should be established in a complemental relationship in a manner to attain uniform aligment of liquid crystal molecules and hence to reduce free energy due to the liquid crystal molecules, therefore, non-uniformity of display is alleviated.

Claims

1. A liquid crystal display cell including a layer of liquid crystal material sandwiched between a pair of opposing parallel plates each carrying an electrode coating, said liquid crystal display cell further comprising:

a first micro groove structure consisting of a multiplicity of grooves provided at the interfacial surface of the electrode coating in contact with the liquid crystal layer for defining the direction of the liquid crystal molecules in the liquid crystal layer in the plane of said interfacial surface; and

a second micro groove structure of a multiplicity of substantially saw-tooth micro grooves at the interfacial surface of the electrode coating in contact with the liquid crystal layer, said substantially saw-tooth micro grooves having a profile for defining the inclination of the liquid crystal molecules in the liquid crystal layer with respect to said plane of said interfacial surface.

2. The liquid crystal display cell according to claim 1, wherein said second micro groove structure is superimposed on said first micro groove structure.

3. A liquid crystal display cell comprising:

first and second opposing plates each carrying an electrode coating;

a layer of liquid crystal material sandwiched between said first and said second plates;

a first micro groove structure of a multiplicity of micro grooves provided at both the interfacial surfaces of said first and said second opposing plates in contact with the liquid crystal layer for defining the direction of the alignment of the liquid crystal molecules in the liquid crystal layer in the planes of said interfacial surfaces; and

a second micro groove structure of a multiplicity of substantially saw-tooth micro grooves on both the interfacial surfaces of said first and said second opposing plates in contact with the liquid crystal layer;

said substantially saw-tooth micro grooves having a profile for defining the inclination of the alignment of the liquid crystal molecules with respect to said planes of said interfacial surfaces in the liquid crystal layer;

said second micro groove structure at the interfacial surface at the first plate having an inclination angle which is equal to that at the second plate.

4. A twisted nematic liquid crystal display cell comprising:

first and second opposing plates each carrying an electrode coating;

a layer of liquid crystal material sandwiched between said first and said second plates;

a first micro groove structure of a multiplicity of grooves provided at both the interfacial surfaces of said first and said second opposing plates in contact with the liquid crystal layer for defining the direction of the alignment of the liquid crystal molecules in the liquid crystal layer in the planes of said interfacial surfaces, said first micro groove structure at the first plate being positioned at a right angle with said first micro groove structure at the second plate for twisting the alignment of the liquid crystal molecules; and

a second micro groove structure of a multiplicity of substantially saw-tooth micro grooves on both the interfacial surfaces of said first and said second opposing plates in contact with the liquid crystal layer;

said substantially saw-tooth micro grooves having a profile for defining the inclination of the alignment of the liquid crystal molecules with respect to said planes of said interfacial surfaces in the liquid crystal layer;

said second micro groove structure at the interfacial surface at the first plate having an inclination angle which is equal to that at the second plate.