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US 5,473,449 AGranted
Liquid crystal display with a ferroelectric film control layer
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsYasuhiko Takemura, Toshimitsu Konuma, Shunpei Yamazaki
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Abstract
A liquid crystal display capable of displaying stable images by the use of a ferroelectric film is driven by scanning the screen once per sub-frame having different periods of time which are defined to integrally form a frame within which displaying an image is completed. One or more sub-frames or no sub-frame is selected to generate selection signals for displaying images. The shade of gray can be controlled in accordance with the combination of the selected sub-frames.
Claims7
An electro-optical device comprising:
- a linear wiring;
- a first pixel electrode;
- a ferroelectric film sandwiched between said linear wiring and said first pixel electrode;
- a second pixel electrode in the form of strip or plane;
- and
- an electro-optical modulating layer provided between said first pixel electrode and said second pixel electrode, said ferroelectric film being interposed between said electro-optical modulating layer and said first pixel electrode, said electro-optical modulating layer comprising a material selected from the group consisting of ferroelectric liquid crystal and anti-ferroelectric liquid crystal,
- wherein relation P.sub.S S.sub.2 d.sub.1 /.epsilon..sub.1 S.sub.1 <100 is satisfied where P.sub.S is a spontaneous polarization of said ferroelectric film, S.sub.2 is an area of an overlapped portion of said first pixel electrode with said second pixel electrode, d.sub.1 is a thickness of said electro-optical modulating layer, .epsilon..sub.1 is a dielectric constant of the material of said electro-optical modulating layer, and S.sub.1 is an areal of an overlapped portion of said first pixel electrode with said linear wiring.
4 more elements
An electro-optical device comprising:
- a linear wiring;
- a first pixel electrode;
- a ferroelectric film sandwiched between said linear wiring and said first pixel electrode;
- a second pixel electrode in the form of strip or plane;
- and
- an electro-optical modulating layer provided between said first pixel electrode and said second pixel electrode, said ferroelectric film being interposed between said electro-optical modulating layer and said first pixel electrode, said electro-optical modulating layer comprising a material selected from the group consisting of ferroelectric liquid crystal and anti-ferroelectric liquid crystal,
- wherein said ferroelectric film comprises a material selected from the group consisting of barium titanate and PbZr.sub.1-x Ti.sub.x O.sub.3.
4 more elements
An electro-optical device comprising:
- a linear wiring;
- a first pixel electrode;
- a ferroelectric film sandwiched between said linear wiring and said first pixel electrode;
- a second pixel electrode in the form of strip or plane;
- and
- an electro-optical modulating layer provided between said first pixel electrode and said second pixel electrode and between said ferroelectric film and said second pixel electrode, said electro-optical modulating layer comprising a material selected from the group consisting of ferroelectric liquid crystal and anti-ferroelectric liquid crystal,
- wherein said ferroelectric film comprises a material selected from the group consisting of barium titanate and PbZr.sub.1-x Ti.sub.x O.sub.3 and has a thickness no smaller than 300 nm.
4 more elements
A liquid crystal display device comprising:
- a pair of substrates opposed to each other;
- a first plurality of conductive strips formed on one of said substrates;
- a second plurality of conductive strips orthogonal to said first plurality of conductive strips and formed on the other one of said substrates, whereby a plurality of pixels are defined at each intersection of said first and second strips;
- a liquid crystal material comprising a material selected from the group consisting of a ferroelectric liquid crystal, material and an anti-ferroelectric liquid crystal material and interposed between said substrates having said first and second conductive strips formed thereon;
- and
- a ferroelectric film interposed between said liquid crystal material and one of said first and second conductive strips,
- wherein said ferroelectric film comprises barium titanate.
4 more elements
Dependencies are inferred from the claim text.