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US 7,145,536 B1Granted
Liquid crystal display device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei Yamazaki, Jun Koyama
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Abstract
An object of the present invention is to provide a small-sized active matrix type liquid crystal display device that may achieve large-sized display, high precision, high resolution and multi-gray scales. According to the present invention, gray scale display is performed by combining time ratio gray scale and voltage gray scale in a liquid crystal display device which performs display in OCB mode. In doing so, one frame is divided into subframes corresponding to the number of bit for the time ratio gray scale. Initialize voltage is applied onto the liquid crystal upon display of a subframe.
Claims61
A liquid crystal display device comprising:
- an active matrix substrate comprising an active matrix circuit in which a plurality of pixel TFTs are disposed in a matrix, and a source driver and a gate driver that drive the active matrix circuit;
- and
- an opposing substrate comprising an opposing electrode,
- wherein the liquid crystal display device is optically compensated bend mode;
- and
- wherein the liquid crystal display device is configured to conduct voltage gray scale and time ratio gray scale at the same time by using n bit out of m bit digital data as information for voltage gray scale, and (m−n) bit as information for time ratio gray scale, wherein m and n are positive numbers equal to or greater than 2 and satisfy m>n.
3 more elements
A liquid crystal display device comprising:
- an active matrix substrate comprising an active matrix circuit in which a plurality of pixel TFTs are disposed in a matrix, and a source driver and a gate driver that drive the active matrix circuit;
- an opposing substrate comprising an opposing electrode;
- and
- a circuit which converts m bit digital video data into n bit digital video data and provides the n bit digital video data to the source driver, wherein m and n are positive numbers equal to or greater than 2 and satisfy m>n,
- wherein the liquid crystal display device is configured to:
- form an image for one frame comprising 2m−n subframes by performing voltage gray scale and time ratio gray scale that uses (m−n) bit at the same time, and;
- apply voltage which makes an orientation of liquid crystal to a bend orientation on starting display of the 2m−n subframes.
4 more elements
A liquid crystal display device comprising:
- an active matrix substrate comprising an active matrix circuit in which a plurality of pixel TFTs are disposed in a matrix, and a source driver and a gate driver that drive the active matrix circuit;
- and
- a circuit which converts m bit digital video data into n bit digital video data and provides the n bit digital video data to the source driver, wherein m and n are positive numbers equal to or greater than 2 and satisfy m>n,
- wherein the liquid crystal display device is configured to:
- form an image for one frame comprising 2m−n subframes by performing voltage gray scale method and time ratio gray scale that uses (m−n) bit at the same time;
- and
- apply voltage which makes an orientation of liquid crystal to a bend orientation on starting display of the frame which comprises 2m−n subframes.
4 more elements
A liquid crystal display device comprising:
- a first substrate;
- a plurality of pixel thin film transistors disposed in a matrix form over the substrate;
- a source driver operationally connected to said plurality of pixel thin film transistors;
- an opposing substrate provided with an opposing electrode;
- and
- a liquid crystal layer interposed between the first substrate and the opposing electrode, said liquid crystal layer having a π cell structure;
- and
- a digital video data time ratio gray scale processing circuit, operationally connected to said source driver,
- wherein a m bit digital video data inputted to the digital video data time ratio gray scale processing circuit is converted into an n bit digital video data for voltage gray scale while (m−n) bit data of the m bit digital video data is used for time ratio gray scale.
6 more elements
A method of driving a liquid crystal display device comprising:
- an active matrix substrate comprising an active matrix circuit in which a plurality of pixel TFTs are disposed in a matrix, and a source driver and a gate driver that drive the active matrix circuit;
- and
- an opposing substrate comprising an opposing electrode;
- wherein the method of driving the liquid crystal display device comprises:
- performing display by optically compensated bend mode, and
- conducting voltage gray scale and time ratio gray scale at the same time by using n bit out of m bit digital data as information for voltage gray scale, and (m−n) bit as information for time ratio gray scale, wherein m and n are positive numbers equal to or greater than 2 and satisfy m>n.
3 more elements
A method of driving a liquid crystal display device comprising:
- an active matrix substrate comprising an active matrix circuit in which a plurality of pixel TFTs are disposed in a matrix, and a source driver and a gate driver that drive the active matrix circuit;
- an opposing substrate comprising an opposing electrode;
- and
- a circuit which converts m bit digital video data inputted from the external into n bit digital video data and provides the n bit digital video data to the source driver, wherein m and n are positive numbers equal to or greater than 2 and satisfy m>n,
- wherein the method of the liquid crystal display device comprises:
- forming an image for one frame comprising 2m−n subframes by performing voltage gray scale and time ratio gray scale that uses (m−n) bit at the same time, and;
- applying voltage which makes an orientation of liquid crystal to a bend orientation on starting display of the 2m−n subframes.
4 more elements
A liquid crystal display device comprising:
- an active matrix circuit including a plurality of pixel TFTs;
- an active matrix substrate including a source driver and a gate driver that control the active matrix circuit;
- an opposing substrate having an opposing electrode;
- a liquid crystal interposed between the active matrix substrate and the opposing substrate;
- and
- a circuit converting a video data into a digital video data for a gradation display using voltage gray scale and time ratio gray scale;
- wherein the source driver comprises a circuit converting the digital video data to an analog video data.
4 more elements
A liquid crystal display device comprising:
- an active matrix circuit including a plurality of pixel TFTs;
- an active matrix substrate including a source driver and a gate driver that drive the active matrix circuit;
- an opposing substrate having an opposing electrode;
- a liquid crystal interposed between the active matrix substrate and the opposing substrate;
- a circuit converting an first analog video data to a first digital video digital data;
- a circuit converting the first digital video digital data into a second digital video data for a gradation display using voltage gray scale and time ratio gray scale;
- and
- a circuit converting the second digital video data to an second analog video data.
5 more elements
A method for driving a liquid crystal display device comprising:
- an active matrix circuit including a plurality of pixel TFTs;
- a source driver and a gate driver controlling the active matrix-circuit;
- a liquid crystal;
- and
- a circuit converting a first digital video data into a second digital video data for a gradation display using voltage gray scale and time ratio gray scale;
- wherein the source driver converts the second digital video data to an analog video data;
- and supplies the analog video data to the active matrix circuit;
- and
- wherein the active matrix circuit forms an image comprising one frame using a plurality of subframes based on the analog video data.
6 more elements
A method for driving a liquid crystal display device comprising:
- an active matrix circuit including a plurality of pixel TFTs;
- a source driver and a gate driver controlling the active matrix circuit;
- a liquid crystal;
- a circuit converting a first analog video data to a first digital video data;
- a circuit converting the first digital video data into a second digital video data for a gradation display using voltage gray scale and time ratio gray scale;
- and
- a circuit converting the second digital video data to a second analog video data;
- wherein the source driver supplies the second analog video data to the active matrix circuit;
- and
- wherein the active matrix circuit forms an image comprising one frame using a plurality of subframes based on the second analog video data.
7 more elements
Dependencies are inferred from the claim text.