Display apparatus

• US 6,054,971 A
• Filed: 05/12/1994
• Issued: 04/25/2000
• Est. Priority Date: 02/20/1991
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Okada, Shinjiro, Inaba, Yutaka
• Primary Examiner(s): LAO, LUNYI
• Application Number:
  US08/241,680
• Time in Patent Office: 2,175 Days
• Field of Search: 345/87, 345/89, 345/90, 345/97, 345/98, 345/185, 345/63, 345/147, 359/54, 359/87, 359/62, 349/33
• US Class Current: 345/89
• 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 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/207 by domain size control G09G3/3637 takes precedence
• CPC Class Codes: G09G 3/3637 with intermediate tones displayed by domain size control domain size control in flat matrix panels other than liquid crystal displays having memory effects G09G3/207

Abstract

A ferroelectric liquid crystal apparatus comprising a liquid crystal cell having a ferroelectric liquid crystal carried between electrode substrates, means for producing a voltage signal for writing the information by applying an electric field via the electrode substrate and driving the ferroelectric liquid crystal, wherein voltage signal producing means determines the voltage signal value with reference to the drive status of a ferroelectric liquid crystal before writing, in writing the information.

Claims

1. A ferroelectric liquid crystal display apparatus comprising:

an active matrix liquid crystal cell comprising electrode substrates and a ferroelectric liquid crystal sandwiched therebetween; and

voltage signal producing means for applying an electric field to said ferroelectric liquid crystal for driving said ferroelectric liquid crystal and for writing information thereon,

wherein pixels constituting said liquid crystal cell are supplied with a writing voltage after a reset and perform gradation displaying according to the writing voltage, and

in writing gradation information, said voltage signal producing means determines a current value of the writing voltage with reference to a voltage-transmittance characteristic of the liquid crystal according to previous gradation image information.

2. A ferroelectric liquid crystal display apparatus according to claim 1, wherein said voltage signal producing means has a memory for storing the previous gradation image information, and a comparator for comparing the previous gradation image information stored in said memory with current image information to be written at present.