Method and apparatus for driving liquid crystal display device

• US 5,204,660 A
• Filed: 10/04/1991
• Issued: 04/20/1993
• Est. Priority Date: 10/05/1990
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Kamagami, Shinichi, Morita, Hiroshi
• Primary Examiner(s): Weldon, Ulysses
• Assistant Examiner(s): CHOW, DOON Y
• Application Number:
  US07/771,509
• Time in Patent Office: 564 Days
• Field of Search: 340/784, 340/784 C, 340/784 D, 340/765, 340/805, 359/55, 359/57, 358/241
• US Class Current: 345/95
• CPC Class Codes: G09G 2320/0204 Compensation of DC component across the pixels in flat panels
• CPC Class Codes: G09G 3/367 with a nonlinear element in series with the liquid crystal cell, e.g. a diode, or M.I.M. element
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

In a liquid crystal display device, MIM type nonlinear resistive swiching elements are connected to pixel electroes, respectively, counter electrodes are arranged to oppose the pixel electrodes and, a liquid crystal layer having a threshould voltage Vth (V) and a saturation voltage Vsat (V) is arranged between the pixel electrodes and the counter electrodes. A voltage having a voltage waveform constituted by a select period in which the signal voltage is applied and a nonselect period in which the signal voltage is held is generated between said electrodes, and an absolute value Vb (V) of the voltage applied between said electrodes during the nonselect period satisfies a relation of:

V'"'"'/2-0.4≦Vb≦V'"'"'/2+0.5

(where V'"'"'=Vth+Vsat).

Claims

1. A method of driving a liquid crystal display device, said liquid crystal display device comprising:

switching elements each having a nonlinear current-voltage characteristic which is asymmetrical between positive and negative directions of voltage application;

a plurality of pixels each incorporating said switching element; and

a liquid crystal having a threshold voltage Vth (V) and a saturation voltage Vsat (V) as electrooptical characteristics,

wherein said liquid crystal display device is time-divisionally driven by a voltage waveform constituted by a select period in which a signal voltage is written in predetermined pixels and a nonselect period in which the written signal voltage is held, and an absolute value Vb (V) of the voltage applied to said pixels during the nonselect period satisfies a relation of;

space="preserve" listing-type="equation">V'"'"'/2-0.4≦

Vb≦

V'"'"'/2+0.5

(where V'"'"'=Vth+Vsat).

2. A method according to claim 1, wherein the absolute value Vb (V) of the voltage is set within a range of 2.2 to 3.1 volts.

3. A method according to claim 1, wherein the absolute value Vb (V) is set within a range of 2.4 to 2.9 volts.

4. A liquid crystal display device comprising:

switching elements each having a nonlinear current-voltage characteristic which is asymmetrical between positive and negative directions of voltage application;

a plurality of pixel electrodes connected to said switching elements;

a plurality of counter electrodes arranged to oppose said pixel electrodes;

a liquid crystal layer arranged between said pixel electrodes and said counter electrodes and having a threshold voltage Vth (V) and a saturation voltage Vsat (V) as electrooptical characteristics; and

means for generating a signal voltage applied between predetermined counter electrodes and pixel electrodes, thereby time-divisionally driving said counter electrodes and said pixel electrodes,

wherein a voltage having a voltage waveform constituted by a select period in which the signal voltage is applied and a nonselect period in which the signal voltage is held is generated between said electrodes, and an absolute value Vb (V) of the voltage applied between said electrodes during the nonselect period satisfies a relation of;

space="preserve" listing-type="equation">V'"'"'/2-0.4≦

Vb≦

V'"'"'/2+0.5

(where V'"'"'=Vth+Vsat).

5. An apparatus according to claim 4, wherein the absolute value Vb (V) of the voltage is set within a range of 2.2 to 3.1 volts.

6. An apparatus according to claim 4, wherein the absolute value Vb (V) is set within a range of 2.4 to 2.9 volts.

7. An apparatus according to claim 4, wherein said pixel electrodes are arranged in a matrix manner.

8. An apparatus according to claim 4, wherein each switching element is of a metal-insulator-metal type and includes a first metal layer, an insulating layer formed on said first metal layer, and a second metal layer formed on said insulating layer and electrically connected to said pixel electrodes.