Driving method for display device and display apparatus

• US 5,808,594 A
• Filed: 09/26/1995
• Issued: 09/15/1998
• Est. Priority Date: 09/26/1994
• Status: Expired due to Fees

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Tsuboyama, Akira, Iwasaki, Manabu, Katakura, Kazunori
• Primary Examiner(s): WU, XIAO MIN
• Application Number:
  US08/534,043
• Time in Patent Office: 1,085 Days
• Field of Search: 345/147, 345/148, 345/149, 345/103, 345/67, 345/87, 345/88, 345/89, 345/98, 345/99, 345/100, 345/94, 345/9, 345/96, 345/208, 345/210
• US Class Current: 345/89
• 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 2320/10 Special adaptations of display systems for operation with variable images
• 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 3/364 with use of subpixels
• CPC Class Codes: G09G 5/14 Display of multiple viewports

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.

Claims

1. A driving method for a display device of a type including scanning lines arranged to form plural pixels comprising at least two types of pixels having mutually different areas inclusive of larger pixels and smaller pixels, said driving method comprising:

driving the display device to effect a first frame display mode wherein only scanning lines corresponding to the larger pixels are vertically scanned, and

driving the display device to effect a second frame display mode wherein all the scanning lines corresponding to the larger pixels and the smaller pixels are scanned to display a larger number of gradation levels than in the first display mode.

2. A driving method according to claim 1, wherein when image data is changed only for a portion of the pixels among all the pixels, only scanning lines corresponding to the larger pixels in a region including the portion of the pixels for which the image data is changed are vertically scanned.

3. A driving method according to claim 1, wherein when image data is changed for a portion of pixels among all the pixels corresponding to a number of scanning lines exceeding a prescribed number, only scanning lines corresponding to the larger pixels among the portion of pixels are vertically scanned.

4. A driving method according to claim 1, wherein for displaying a motion picture, only scanning lines corresponding to the larger pixels are vertically scanned.

5. A driving method according to claim 1, wherein two larger pixels are disposed positionally symmetrically with respect to a smaller pixel disposed between the two larger pixels.

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

7. A driving method according to claim 1, wherein the scanning lines corresponding to the larger pixels are vertically scanned with skipping of at least one scanning line in a prescribed region and without skipping in another region.

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

9. 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.

10. 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.

11. 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.

12. A driving method according to any one of claims 1-11, wherein said plural pixels include a unit of pixels comprising 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.

13. A driving method according to claim 1, wherein said display device is adapted for gradational display based on given gradation data.

14. A driving method according to claim 1, including, as selective modes, a first mode of effecting a gradational display at a first number of gradation levels, and a second mode of effecting a gradational display at a second number less than the first number of gradation levels or a binary display.

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 scanning lines corresponding to said larger pixels also have thereon pixels smaller than said larger pixels.

18. A driving method according to claim 1, wherein said plural pixels include a unit of pixels including pixels having different areas disposed on an identical scanning line which receive identical data signals.

19. A driving method according to claim 1, wherein said plural pixels include a unit of pixels including pixels having different areas disposed on an identical scanning line which receive different data signals.

20. A display apparatus, comprising:

a display device including scanning lines arranged to form plural pixels comprising at least two types of pixels having mutually different areas inclusive of larger pixels and smaller pixels, and

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

21. A driving method for display device of a type including a pair of oppositely disposed substrates having thereon a group of scanning electrodes and a group of data electrodes intersecting the scanning electrodes so as to form a sub-pixel at each intersection of the scanning electrodes and the data electrodes, a plurality of the sub-pixels having different areas forming one of plural pixels,

said driving method comprising selectively driving the scanning electrodes and the data electrodes depending on given image data so as to turn on the sub-pixels in various patterns to display multiple gradation levels at each of the plural pixels,

said driving method including one frame period comprising a plurality of fields wherein a scanning electrode corresponding to a sub-pixel having the largest area among the plurality of sub-pixels is scanned in a larger number of fields than a scanning electrode corresponding to a sub-pixel having the smallest area among the plurality of sub-pixels.

22. A driving method according to claim 21, wherein a scanning electrode corresponding to a sub-pixel having the largest area among the plurality of sub-pixels and present in an image region for which image data is changed is preferentially scanned to effect a vertical scanning for providing one frame of display.

23. A driving method according to claim 21 or 22, wherein said scanning electrode corresponding to the sub-pixel having the largest area is scanned a larger number of times than the other scanning electrodes in one frame period.

24. A display apparatus, comprising:

a display device including a pair of oppositely disposed substrates having thereon a group of scanning electrodes and a group of data electrodes intersecting the scanning electrodes so as to form a sub-pixel at each intersection of the scanning electrodes and the data electrodes, a plurality of the sub-pixels having different areas forming one of plural pixels, and

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

25. A driving method for a display device of a type including scanning lines arranged to form plural pixels comprising at least two types of pixels having mutually different areas inclusive of larger pixels and smaller pixels,

said driving method comprising driving the display device to effect period comprising at least three fields wherein only scanning lines corresponding to the larger pixels are vertically scanned in each of two of said at least three fields, and only scanning lines corresponding to the smaller pixels are vertically scanned in a remaining one of said at least three fields.

26. A display apparatus, comprising:

a display device including scanning lines arranged to form plural pixels comprising at least two types of pixels having mutually different areas inclusive of larger pixels and smaller pixels, and

drive means for driving said apparatus to effect one frame period comprising at least three fields wherein only scanning lines corresponding the larger pixels are vertically scanned in each of two of said at least three fields, and only scanning lines corresponding to the smaller pixels are vertically scanned in a remaining one of said at least three fields.