Driving method for display device and display apparatus

• US 5,963,190 A
• Filed: 06/18/1997
• Issued: 10/05/1999
• Est. Priority Date: 09/26/1994
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tsuboyama, Akira, Iwasaki, Manabu, Katakura, Kazunori
• Primary Examiner(s): Mengistu, Amare
• Application Number:
  US08/877,891
• Time in Patent Office: 839 Days
• Field of Search: 345/88, 345/89, 345/93, 345/100, 345/103, 345/147, 345/149, 345/152, 349/85, 349/96, 349/144, 349/172, 348/256
• US Class Current: 345/103
• CPC Class Codes: G02F 1/134345 Subdivided pixels, e.g. for grey scale or redundancy
• 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 2310/061 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 3/2074 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 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 3/364 with use of subpixels

Abstract

A display device is constituted by scanning lines arranged to form plural pixels including at least two types of pixels having mutually different areas inclusive of larger pixels and smaller pixels. The display device is driven by a driving method including a vertical scanning period wherein only scanning lines corresponding to the larger pixels are vertically scanned, and a second vertical scanning period wherein only scanning lines corresponding to the smaller pixels are vertically scanned.

Claims

1. A driving method for a display device of the type comprising a plurality of scanning lines and a plurality of data lines arranged so as to form a matrix of pixels each formed at an intersection of the scanning lines and the data lines, said pixels comprising at least two types of pixels having mutually different areas inclusive of larger pixels and smaller pixels, said plurality of scanning lines including first-type scanning lines having thereon the larger pixels and second-type scanning lines having thereon the smaller pixels, said matrix of pixels being divided into a plurality of display elements each adapted for a gradational display and comprising a plurality of pixels including at least one of the larger pixels and at least one of the smaller pixels,

said driving method comprising a first vertical scanning period wherein only the first-type scanning lines are vertically scanned, and a second vertical scanning period wherein only the second-type scanning lines are vertically scanned,

wherein each display element is driven by selectively turning on and off the plurality of pixels thereon so as to alleviate a vertical shift of gravity center of brightness at different gradation levels.

2. A driving method according to claim 1, including a partial rewrite period wherein only a part of the scanning lines corresponding to a region including pixels for which image data is changed is scanned, and said partial rewrite period includes said first and second vertical scanning periods.

3. A driving method according to claim 1, including said first and second vertical scanning periods in a period of scanning all the scanning lines.

4. A driving method according to claim 1, wherein said first vertical scanning period includes a period of vertically scanning non-adjacent scanning line while skipping other scanning lines and a sub-period of scanning the skipped scanning lines, and said second vertical scanning period includes a sub-period of vertically scanning non-adjacent scanning lines while skipping other scanning lines and a sub-period of scanning the skipped scanning lines.

5. A driving method according to claim 1, wherein said second vertical scanning period includes plural sub-vertical scanning periods, and said first vertical scanning period includes plural sub-vertical scanning periods, between which one of said sub-vertical scanning periods of the second vertical scanning period is inserted.

6. A driving method according to claim 1, wherein in each of said first and second vertical scannings, vertical scanning is performed while skipping at least one scanning line.

7. A driving method according to claim 1, wherein two of the larger pixels are disposed positionally symmetrically with respect to a smaller pixel disposed between the two larger pixels so as to form one display element.

8. A driving method according to claim 1, wherein at least two adjacent first-type scanning lines among the first-type scanning lines corresponding to the larger pixels are simultaneously supplied with a scanning selection signal.

9. A driving method according to claim 1, wherein the first-type scanning lines are vertically scanned with skipping of at least one first-type scanning line in a prescribed region and without skipping in another region.

10. A driving method according to claim 1, wherein said pixels comprise a chiral smectic liquid crystal.

11. A driving method according to claim 1, wherein said display device comprises a pair of substrates and a chiral smectic liquid crystal disposed in a bookshelf layer structure between the substrates.

12. A driving method according to claim 1, wherein said display device comprises a pair of substrates and a chiral smectic liquid crystal having a phase transition series lacking cholesteric phase disposed between the substrates.

13. A driving method according to claim 1, wherein said display device comprises a pair of substrates and a chiral smectic liquid crystal disposed between the substrates, only one of the substrates having been subjected to rubbing.

14. A driving method according to any one of claims 1-13, wherein each display element comprises a smaller pixel, at least two larger pixels disposed positionally symmetrically with respect to the smaller pixel, and a medium pixel having a smaller area than the larger pixel and disposed on the same scanning line as the larger pixel.

15. A driving method according to claim 1, wherein said plural pixels include color pixels of red, blue and green.

16. A driving method according to claim 1, wherein said plural pixels include color pixels of red, blue and green each adapted for gradational display, one of the red, blue and green color pixels having a number of gradation levels different from those of the other color pixels.

17. A driving method according to claim 1, wherein said first-type scanning lines having thereon said larger pixels also have thereon pixels smaller than said larger pixels.

18. A driving method according to claim 1, wherein each said display element includes pixels having different areas disposed on an identical scanning line which receive identical data signals.

19. A driving method according to claim 1, wherein each said display element includes pixels having different areas disposed on an identical scanning line which receive different data signals.

20. A display apparatus, comprising:

a display device comprising a plurality of scanning lines and a plurality of data lines arranged so as to form a matrix of pixels each formed at an intersection of the scanning lines and the data lines, said pixels comprising at least two types of pixels having mutually different areas inclusive of larger pixels and smaller pixels, said plurality of scanning lines including first-type scanning lines having thereon the larger pixels and second-type scanning lines having thereon the smaller pixels, said matrix of pixels being divided into a plurality of display elements each adapted for a gradational display and comprising a plurality of pixels including at least one of the larger pixels and at least one of the smaller pixels; and

drive means for driving the display device according to a driving method of claim 1.

21. A driving method for a display device of the type comprising a plurality of scanning lines and a plurality of data lines arranged so as to form a matrix of pixels each formed at an intersection of the scanning lines and the data lines, said pixels comprising at least two types of pixels having mutually different areas inclusive of larger pixels and smaller pixels, said plurality of scanning lines including first-type scanning lines having thereon the larger pixels and second-type scanning lines having thereon the smaller pixels, said plurality of data lines including first-type data lines and second-type data lines providing pixels of mutually different areas on a common scanning line,

said driving method comprising a first vertical scanning period wherein only the first-type scanning lines are vertically scanned, and a second vertical scanning period wherein only the second-type scanning lines are vertically scanned.

22. A driving method according to claim 21, wherein said matrix of pixels are divided into a plurality of display elements each adapted for a gradational display and comprising a plurality of pixels formed at intersections of a plurality of scanning lines including at least one of the first-type scanning lines and at least one of the second-type scanning lines with a plurality of data lines including at least one of the first-type data lines and at least one of the second-type data lines, and

each display element is driven by selectively turning on and off the plurality of pixels therein so as to alleviate a vertical shift of gravity center of brightness at different gradation levels.

23. A display apparatus, comprising:

a display device of the type comprising a plurality of scanning lines and a plurality of data lines arranged so as to form a matrix of pixels each formed at an intersection of the scanning lines and the data lines, said pixels comprising at least two types of pixels having mutually different areas inclusive of larger pixels and smaller pixels, said plurality of scanning lines including first-type scanning lines having thereon the larger pixels and second-type scanning lines having thereon the smaller pixels, said plurality of data lines including first-type data lines and second-type data lines providing pixels of mutually different areas on a common scanning line; and

drive means for driving the display device according to a driving method of claim 21.

24. A display apparatus according to claim 23, wherein said matrix of pixels is divided into a plurality of display elements each adapted for a gradational display and comprising a plurality of pixels formed at intersections of a plurality of scanning lines including at least one of the first-type scanning lines and at least one of the second-type scanning lines with a plurality of data lines including at least one of the first-type data lines and at least one of the second-type data lines, and

each display element is driven by selectively turning on and off the plurality of pixels thereon so as to alleviate a vertical shift of gravity center of brightness at different gradation levels.