Liquid crystal apparatus

• US 5,815,131 A
• Filed: 09/04/1997
• Issued: 09/29/1998
• Est. Priority Date: 04/24/1989
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tsuboyama, Akira, Hotta, Yoshio, Inaba, Yutaka, Taniguchi, Osamu, Katakura, Kazunori, Mihara, Tadashi, Iwayama, Mitsuo
• Primary Examiner(s): Saras, Steven J.
• Assistant Examiner(s): Bell, Paul A.
• Application Number:
  US08/923,464
• Time in Patent Office: 390 Days
• Field of Search: 345/94, 345/95, 345/96, 345/97, 345/98, 345/99, 345/100
• US Class Current: 345/94
• CPC Class Codes: G09G 2310/0205 Simultaneous scanning of several lines in flat panels
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• 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 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

A liquid crystal apparatus includes: a ferroelectric liquid crystal device comprising an electrode matrix including a plurality of scanning lines and a plurality of data lines intersecting with the scanning lines, and a ferroelectric liquid crystal disposed between the scanning lines and data lines, and a driver for sequentially applying a scanning signal to the scanning lines for selecting a particular scanning line, and for applying data signals for the pixels on the selected scanning line to the data lines. Each of the data signals has a plurality of pulses including a pulse in a controlled phase and a pulse in an auxiliary phase, and the scanning signal for the selected scanning line has a compensation pulse for compensating the pulse in the auxiliary phase of a data signal for a pixel on the selected scanning line.

Claims

1. A liquid crystal apparatus, comprising:

(a) a display panel having a matrix formed by a plurality of scanning lines and a plurality of data lines and a liquid crystal having a memory function;

(b) drive means for sequentially applying a scanning selection signal to the scanning lines and applying data signals to the data lines in synchronism with the scanning selection signal; and

(c) control means for;

selecting either a first operation of scanning all the scanning lines with the scanning selection signal in response to a whole-area rewrite demand or a second operation of scanning a subset of the scanning lines with the scanning selection signal in response to a partial rewrite demand, and

controlling the drive means so that, in the first operation, two scanning selection signals overlapping in time are successively applied to two scanning lines respectively and, in the second operation, two scanning selection signals not overlapping in time are successively applied to two scanning lines respectively.

2. An apparatus according to claim 1, wherein each scanning selection signal has a clearing phase and control phase, and said control means controls the drive means so that the clearing phases of two successively applied scanning selection signals overlap in time with each other.

3. An apparatus according to claim 1, wherein said liquid crystal is a ferroelectric liquid crystal.