Active matrix type liquid-crystal display unit and method of driving the same

• US 6,243,064 B1
• Filed: 08/10/1999
• Issued: 06/05/2001
• Est. Priority Date: 11/07/1995
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Hirakata, Yoshiharu
• Primary Examiner(s): LAO, LUNYI
• Application Number:
  US09/371,797
• Time in Patent Office: 665 Days
• Field of Search: 349/41, 349/42, 349/47, 349/48, 345/96, 345/92, 345/94, 345/95, 345/204, 345/208, 345/209, 345/210
• US Class Current: 345/96
• CPC Class Codes: G09G 2300/0434 Flat panel display in which a field is applied parallel to the display plane
• CPC Class Codes: G09G 2300/0814 used for selection purposes, e.g. logical AND for partial update
• CPC Class Codes: G09G 2300/0823 used to establish symmetry in driving, e.g. with polarity inversion
• CPC Class Codes: G09G 3/3659 the addressing of the pixel involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependant on signal of two data electrodes

Abstract

A data signal having a single polarity is outputted from a data driver of an in-plane switching type liquid-crystal display unit. In a unit pixel, an input transistor and an exhaust transistor T2 are connected to one electrode of a liquid-crystal element LC, and an input transistor and an exhaust transistor are connected to the other electrode. One input transistor and one exhaust transistor connected to the same scanning line are paired, and another input transistor and another exhaust transistor connected to another same scanning line are paired. Those paired transistors are alternately driven, thereby being capable of inverting the potential between electrodes of the liquid-crystal element even when the polarity of the data signal is single.

Claims

1. A liquid crystal device comprising:

a pair of substrates;

a scanning driver provided over one of said substrates;

a data driver provided over said one of said substrates;

a liquid crystal provided between said substrates;

a plurality of pixels arranged in said liquid crystal device and having a plurality of pairs of first and second electrodes respectively for applying voltages between said first and second electrodes of said plurality of pairs, said first and second electrodes being provided over said one of said substrates to effect the application of said voltages to said liquid crystal of said pixels in an in-plane switching mode,

wherein said liquid crystal of said pixels responds to said voltages in a field inversion, and

wherein the application of each of said voltages is carried out by applying an image write signal to one of said first and second electrodes of corresponding one of said pairs and setting the other of said first and second electrodes of said corresponding one of said pairs to a reference potential, and

wherein a potential level of said image write signal is always of a single polarity.

2. A liquid crystal device comprising:

a pair of substrates;

a scanning driver provided over one of said substrates;

a data driver provided over said one of said substrates;

a liquid crystal provided between said substrates;

a plurality of pixels arranged in said liquid crystal device and having a plurality of pairs of first and second electrodes respectively for applying voltages between said first and second electrodes of said plurality of pairs, said first and second electrodes being provided over said one of said substrates to effect the application of said voltages to said liquid crystal of said pixels in an in-plane switching mode,

wherein said liquid crystal of said pixels responds to said voltages in a line inversion, and

wherein the application of each of said voltages is carried out by applying an image write signal to one of said first and second electrodes of corresponding one of said pairs and setting the other of said first and second electrodes of said corresponding one of said pairs to a reference potential, and

wherein a potential level of said image write signal is always of a single polarity.

3. A liquid crystal device comprising:

a pair of substrates;

a liquid crystal provided between said substrates;

a plurality of pixels arranged in said liquid crystal device and having a plurality of pairs of first and second electrodes respectively for applying voltages between said first and second electrodes of said plurality of pairs, said first and second electrodes being provided over one of said substrates to effect the application of said voltages to said liquid crystal of said pixels in an in-plane switching mode,

wherein said liquid crystal of said pixels responds to said voltages in a field inversion, and

wherein the application of each of said voltages is carried out by applying an image write signal to one of said first and second electrodes of corresponding one of said pairs and setting the other of said first and second electrodes of said corresponding one of said pairs to a reference potential, and

wherein a potential level of said image write signal is always of a single polarity.

4. A liquid crystal device comprising:

a pair of substrates;

a liquid crystal provided between said substrates;

a plurality of pixels arranged in said liquid crystal device and having a plurality of pairs of first and second electrodes respectively for applying voltages between said first and second electrodes of said plurality of pairs, said first and second electrodes being provided over one of said substrates to effect the application of said voltages to said liquid crystal of said pixels in an in-plane switching mode,

wherein said liquid crystal of said pixels responds to said voltages in a line inversion, and

wherein the application of each of said voltages is carried out by applying an image write signal to one of said first and second electrodes of corresponding one of said pairs and setting the other of said first and second electrodes of said corresponding one of said pairs to a reference potential, and

wherein a potential level of said image write signal is always of a single polarity.

5. A liquid crystal device comprising:

a pair of substrates;

a liquid crystal provided between said substrates;

a plurality of pixels arranged in said liquid crystal device and having a plurality of pairs of first and second electrodes respectively for applying voltages between said first and second electrodes of said plurality of pairs, said first and second electrodes being provided over one of said substrates to effect the application of said voltages to said liquid crystal of said pixels in an in-plane switching mode,

wherein said liquid crystal of said pixels responds to said voltages in a field inversion, and

wherein the application of each of said voltages is carried out by applying an image write signal to one of said first and second electrodes of corresponding one of said pairs and setting the other of said first and second electrodes of said corresponding one of said pairs to a reference potential, and

wherein the application of said image write signal and the setting to said reference potential are alternatively carried out to said first electrode and to said second electrode.

6. A liquid crystal device comprising:

a pair of substrates;

a liquid crystal provided between said substrates;

a plurality of pixels arranged in said liquid crystal device and having a plurality of pairs of first and second electrodes respectively for applying voltages between said first and second electrodes of said plurality of pairs, said first and second electrodes being provided over one of said substrates to effect the application of said voltages to said liquid crystal of said pixels in an in-plane switching mode,

wherein said liquid crystal of said pixels responds to said voltages in a line inversion,

wherein the application of each of said voltages is carried out by applying an image write signal to one of said first and second electrodes of corresponding one of said pairs and setting the other of said first and second electrodes of said corresponding one of said pairs to a reference potential, and

wherein the application of said image write signal and the setting to said reference potential are alternatively carried out to said first electrode and to said second electrode.