Drive circuit for color display device

• US 5,982,347 A
• Filed: 05/31/1996
• Issued: 11/09/1999
• Est. Priority Date: 06/01/1995
• Status: Expired due to Fees

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Matsuura, Makoto, Shigeta, Kazuyuki
• Primary Examiner(s): Saras, Steven J.
• Assistant Examiner(s): AWAD, AMR A
• Application Number:
  US08/655,893
• Time in Patent Office: 1,257 Days
• Field of Search: 345/98, 345/99, 345/100, 345/88, 345/152, 345/94, 345/196, 345/197
• US Class Current: 345/88
• CPC Class Codes: G09G 2300/0439 Pixel structures
• CPC Class Codes: G09G 2310/0297 Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
• CPC Class Codes: G09G 3/3629 using liquid crystals having memory effects, e.g. ferroelectric liquid crystals
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A drive circuit for a color display device comprising a plurality of pixels which are wired in matrix through a plurality of data signal lines and a plurality of scanning signal lines; the drive circuit comprising an input means for sampling three-primary color image signals for one line which are inputted through three input lines during a given period t, to write the signals in a memory, and an output means for reading the three-primary color image signals during a certain t/2 period to output the signals to three output lines, and reading the three-primary color image signals during an additional t/2 period different from the certain t/2 period to output the signals to the three output lines. When the drive circuit is used in, e.g., an active matrix liquid-crystal display device, display can be free of flicker and can be in a high resolution.

Claims

1. A drive circuit for a color display device comprising a plurality of pixels which are wired in matrix through a plurality of data signal lines and a plurality of scanning signal lines, said drive circuit comprising:

an input means for sampling three-primary color image signals for one line which are inputted through three input lines during a given period t, to write the signals in a memory; and

an output means for reading the three-primary color image signals sequentially from the memory during a certain t/2 period to output the signals to three output lines, and reading the three-primary color image signals sequentially from the memory during an additional t/2 period different from the certain t/2 period to output the signals to the three output lines,

wherein said certain t/2 period overlaps with said period t, and wherein said output means outputs the three-primary color image signals to the three output lines using different line memories between said certain t/2 period and said additional t/2 period.

2. The drive circuit according to claim 1, wherein said memory is an analog memory.

3. The drive circuit according to claim 1, wherein said given period t is one horizontal scanning period.

4. The drive circuit according to any one of claim 1, 2 or 3, wherein said certain t/2 period and said additional t/2 period are continuous.

5. The drive circuit according to claim 1, wherein said output means outputs image signals with the same three-primary colors to the three output lines during said certain t/2 period and said additional t/2 period.

6. The drive circuit according to claim 5, wherein pixels on adjoining two lines connected to the same data wiring of said color display device have the same colors.

7. The drive circuit according to claim 1, wherein pixels on adjoining two lines connected to the same data wiring of said color display device have different colors.

8. The drive circuit according to claim 6 or 7, wherein pixels on adjoining two lines of said color display device are arranged in shifts of 1.5 pixels.

9. The drive circuit according to claim 8, wherein image signals outputted during said certain t/2 period and said additional t/2 period are outputted matchingly to the pixels arranged in shifts of 1.5 pixels.

10. The drive circuit according to claim 1, wherein in said input means the latter half 1/2 t period of period t during which said image signals are sampled and written in the memory overlaps with said certain 1/2 t period.

11. The drive circuit according to claim 1, wherein said image signals outputted to said output lines are outputted to said data signal lines in parallel.

12. The drive circuit according to claim 1, wherein said color display device is an active matrix liquid-crystal display device in which said plurality of pixels each have a switching element.

13. The drive circuit according to claim 12, wherein said switching element is a thin-film transistor comprising a polycrystalline silicon.

14. A drive circuit for a color display device comprising a plurality of pixels which are wired in matrix through a plurality of data signal lines and a plurality of scanning signal lines, said drive circuit comprising:

an input means for sampling three-primary color image signals for one line which are inputted through three input lines during a given period t, to write the signals in a memory; and

an output means for reading the three-primary color image signals sequentially from the memory during a certain t/2 period to output the signals to three output lines, and reading the three-primary color image signals sequentially from the memory during an additional t/2 period different from the certain t/2 period to output the signals to the three output lines,

wherein said certain t/2 period overlaps with said period t, so as to effect micro-adjustment of the timing of reading from said memory, matchingly to pixel arrangement of said color display device, said micro-adjustment corresponding to a phase difference between a phase of charging a capacitance associated with the display and a phase of period per one pixel of the signals inputted by said input means.

15. A drive circuit for a color display device comprising a plurality of pixels which are wired in matrix through a plurality of data signal lines and a plurality of scanning signal lines, said drive circuit comprising:

an input means for sampling three-primary color image signals for one line which are inputted through three input lines during a given period t, to write the signals in a memory; and

an output means for reading the three-primary color image signals sequentially from the memory during a certain t/2 period to output the signals to three output lines, and reading the three-primary color image signals sequentially from the memory during an additional t/2 period different from the certain t/2 period to output the signals to the three output lines,

wherein said certain t/2 period overlaps with said period t, and wherein image signals on an n-th line of the odd-numbered field are written in a 2n+1 line and 2n+2 line of said plurality of pixels, and image signals on the n-th line of the even-numbered field are written in the pixels on a 2n line and the 2n+1 line.