Display apparatus

• US 5,654,732 A
• Filed: 01/03/1995
• Issued: 08/05/1997
• Est. Priority Date: 07/24/1991
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Katakura, Kazunori
• Primary Examiner(s): WU, XIAO MIN
• Application Number:
  US08/367,772
• Time in Patent Office: 945 Days
• Field of Search: 345/89, 345/87, 345/103, 345/147, 345/149, 345/152, 345/43, 345/94, 345/100, 345/101, 345/95, 345/96, 345/208, 345/209, 345/210, 359/54, 359/55, 359/56
• US Class Current: 345/95
• CPC Class Codes: G09G 2310/0205 Simultaneous scanning of several lines in flat panels
• 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 2320/041 Temperature compensation
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/207 by domain size control G09G3/3637 takes precedence
• CPC Class Codes: G09G 3/2074 using sub-pixels
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• 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
• CPC Class Codes: G09G 3/364 with use of subpixels

Abstract

A display apparatus comprises a display section having a multiplicity of pixels P₁, P₂, each pixel having first and second bi-stable sub-pixels A, B and A'"'"', B'"'"' which have the same threshold characteristics, and a driver for driving the pixels in such a manner that a first writing pulse A₁ is applied to the first sub-pixel A, A'"'"' so as to write a complete first stable state in the first sub-pixel A, A'"'"', followed by application of a second writing pulse A₂ to write the second stable state, while a first writing pulse B₁ is applied to the second sub-pixel B,B'"'"' to write a complete second stable state in the second sub-pixel B,B'"'"', followed by application of a second writing pulse B₂ to write the first stable state.

Claims

1. A display apparatus comprising:

a display section, having a plurality of driving points, comprising first and second electrode sections disposed opposite to each other and having a liquid crystal sandwiched therebetween, wherein a first polarity pulse is applied to first driving points to set the first driving points entirely at one optical state, a second polarity pulse opposite to the first polarity pulse is applied to the first driving points to set the first driving points at a state of transmissivity α

%, a third polarity pulse opposite to the first polarity pulse is applied to second driving points to set the second driving points at the other optical state, a fourth polarity pulse of the same polarity as the first polarity pulse is applied to the second driving points to set the second driving points at a state of transmissivity α

%, the first polarity pulse is applied to third driving points to set the third driving points entirely at the one optical state, the second polarity pulse opposite to the first polarity pulse is applied to the third driving points at a state of transmissivity (α

+β

)%, the third polarity pulse opposite to the first polarity pulse is applied to fourth driving points to set the fourth driving points at the other optical state, and the fourth polarity pulse of the same polarity as the first polarity pulse is applied to the fourth driving points to set the fourth driving points at a state of transmissivity (α

-β

)%; and

voltage signal applying means for applying a first voltage signal of one polarity to the first and the third driving points entirely to set the first and the third driving points at the one optical state, for applying a second voltage signal opposite to the first voltage signal to the first and the third driving points in response to information, so that the first driving points are set at a state of transmissivity α

% and the third driving points are set at a state of transmissivity (α

+β

)%, for applying a third voltage signal of an opposite polarity to the second and the fourth driving points entirely to set the second and the fourth driving points at the other optical state, and for supplying a fourth voltage signal opposite to the third voltage signal to the second and the fourth driving points in response to information, so that the second driving points are set at a state of transmissivity α

% and the fourth driving points are set at a state of transmissivity (α

-β

)%, thereby equalizing a transmissivity of a pixel composed of the first driving points and the second driving points with a transmissivity of a pixel composed of the third driving points and the fourth driving points.

2. A display apparatus according to claim 1, wherein the plurality of driving points are arranged along plural rows and columns to form a display matrix.

3. A display apparatus according to claim 1, wherein said liquid crystal is a chiral smectic liquid crystal.