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US 5,497,256 AGranted
Normally black mode liquid crystal display apparatus having liquid crystal cell of the first minimum design
AssigneeSharp Kabushiki Kaisha
InventorsKaori Aoyama, Toshiyuki Yoshimizu
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Abstract
A liquid crystal display includes a liquid crystal cell including a pair of substrates and a liquid crystal filled between the substrates, and a phase plate located adjacent to one of the substrates of the liquid crystal cell and having a retardation value of 400 to 500 nm. The wavelength dependency of the retardation value of the phase plate being substantially uniform.
Claims15
A liquid crystal display which operates in a normally black mode, comprising:
- a liquid crystal cell including a pair of substrates and a liquid crystal filled between the substrates, the liquid crystal cell being of a first minimum design;
- and
- a phase plate located adjacent to one of the substrates of the liquid crystal cell and having a retardation value of 400 to 500 nm, the wavelength dependency of the retardation value of the phase plate being substantially uniform, thereby improving display quality in the normally black mode.
A liquid crystal display comprising:
- a liquid crystal cell including a pair of substrates and a liquid crystal filled between the substrates, the liquid crystal being a twisted nematic liquid crystal which undergoes a 90.degree. twist in a predetermined direction;
- a phase plate located adjacent to one of the substrates of the liquid crystal cell and having a retardation value of 400 to 500 nm, the wavelength dependency of the retardation value of the phase plate being substantially uniform;
- and
- first and second polarizing plates located on both sides of the liquid crystal cell, respectively,
- wherein a transmission axis of the second polarizing plate is shifted through an angle of 5.degree. in the predetermined direction from a transmission axis of the first polarizing plate,
- the phase plate is positioned between the first polarizing plate and the liquid crystal cell, and
- a slow axis of the phase plate is shifted through an angle of 10.degree. in the predetermined direction from a rubbing direction of one of the substrates which is adjacent to the phase plate.
4 more elements
A liquid crystal display comprising:
- a liquid crystal cell including a pair of substrates and a liquid crystal filled between the substrates, the liquid crystal being a twisted nematic liquid crystal which undergoes a 90.degree. twist in a predetermined direction;
- a phase plate located adjacent to one of the substrates of the liquid crystal cell and having a retardation value of 400 to 500 nm, the wavelength dependency of the retardation value of the phase plate being substantially uniform;
- and
- first and second polarizing plates located on both sides of the liquid crystal cell, respectively,
- wherein the phase plate is positioned between the first polarizing plate and the liquid crystal cell,
- a transmittance of the first polarizing plate is higher than that of the second polarizing plate,
- a transmission axis of the first polarizing plate is shifted through an angle of 85.degree. to 95.degree. in the predetermined direction from a rubbing direction of one of the substrates which is adjacent to the first polarizing plate, and
- a transmission axis of the second polarizing plate is shifted through an angle of -5.degree. to 10.degree. in the predetermined direction from a rubbing direction of the other substrate which is adjacent to the second polarizing plate.
5 more elements
A method for improving display quality of a liquid crystal display in a black mode comprising the steps of:
- locating a phase plate having a retardation value adjacent to one substrate of a pair of substrates located on either side of a liquid crystal cell of a first minimum design of the liquid crystal display;
- operating the liquid crystal display in the black mode;
- and
- varying the retardation value of the phase plate until the display quality of the liquid crystal display in the black mode is optimized.
1 more element
Dependencies are inferred from the claim text.