Liquid crystal apparatus

• US 5,488,388 A
• Filed: 07/14/1994
• Issued: 01/30/1996
• Est. Priority Date: 03/05/1987
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Terada, Masahiro, Inoue, Hiroshi, Mizutome, Atsushi, Taniguchi, Osamu, Onitsuka, Yoshihiro, Mihara, Tadashi
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): Lao, Lun-Yi
• Application Number:
  US08/274,155
• Time in Patent Office: 565 Days
• Field of Search: 345/87, 345/88, 345/89, 345/90, 345/91, 345/92, 345/94, 345/95, 345/96, 345/97, 345/99, 345/204, 345/208, 345/209, 345/123, 345/151, 359/55, 359/56, 359/100
• US Class Current: 345/97
• CPC Class Codes: G09G 2310/0224 Details of interlacing
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2310/065 Waveforms comprising zero voltage phase or pause
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 3/3629 using liquid crystals having memory effects, e.g. ferroelectric liquid crystals

Abstract

Driving apparatus including scanning electrodes and data electrodes, a liquid crystal assuming first and second optical states according to the polarity of a writing voltage applied thereto and disposed between the scanning and data electrodes, scanning-side and drive-side drivers, and a controller for controlling these drivers. The scanning-side drive supplies first and second scanning selections signals having mutually different voltage wave forms to the scanning electrodes so that the first and second scanning selection signals are applied alternately in respective vertical scanning periods. The data-side driver supplies data pulses to the data electrodes in synchronism with the first and second scanning selection signals so as to form one picture in at least four vertical scanning periods. The controller controls the scanning-side and data-side drivers so as to scroll each picture in at least four vertical scanning periods.

Claims

1. A liquid crystal display apparatus, comprising scanning lines and data lines intersecting each other, with ferroelectric liquid crystal material having a memory property disposed therebetween, to form an electrode matrix and a pixel at each intersection, and adapted to display a motion picture by consecutively displaying a plurality of different pictures on the electrode matrix, each said pixel showing different display states corresponding to different polarities of voltages applied thereto, said display apparatus comprising:

scanning means for applying scanning selection signals to the scanning lines, said scanning means comprising;

first scanning means for sequentially applying a first scanning selection signal, comprising a voltage of one polarity, to the scanning lines to effect odd-numbered frame scanning operations; and

second scanning means for sequentially applying a second scanning selection signal, comprising a voltage of another polarity opposite to the one polarity, to effect even-numbered frame scanning operations, wherein the one polarity and the other polarity are defined with respect to a voltage level applied to a non-selected scanning line which does not receive any of the first and second scanning selection signals; and

data signal output means for supplying data signals to the data lines in synchronism with each of the first and second scanning selection signals, said data signal output means supplying identical data signals to the data lines for at least three consecutive frame scanning operations and for displaying an identical picture for at least two consecutive frame scanning operations of the at least three consecutive frame scanning operations.

2. A display apparatus according to claim 1, wherein a ferroelectric liquid crystal is disposed between the scanning lines and the data lines.

3. A display apparatus according to claim 2, wherein said ferroelectric liquid crystal is a chiral smectic liquid crystal.

4. A display apparatus according to claim 3, wherein said chiral smectic liquid crystal has a helical structure and is disposed in a layer sufficiently thin to release the helical structure in the absence of an electrical field.

5. A display apparatus according to claim 1, wherein said data signal output means supplies identical data signals to the data lines for at least four consecutive frame scanning operations and displays an identical picture for at least three consecutive frame scanning operations of the at least four consecutive frame scanning operations.