Display and method of driving the display capable of reducing current and power consumption without deteriorating quality of displayed images

• US 6,636,187 B2
• Filed: 10/29/1998
• Issued: 10/21/2003
• Est. Priority Date: 03/26/1998
• Status: Expired due to Fees

• Current Assignee: Maxell, Ltd.
• Original Assignee: Fujitsu Limited
• Inventors: Takata, Kiyoshi, Okayasu, Junichi, Tanaka, Shinsuke, Ishida, Katsuhiro, Kondo, Nobuyoshi, Fujisaki, Takashi, Tajima, Masaya, Asami, Fumitaka, Matsui, Naoki, Awata, Yoshimasa
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): ZAMANI, ALI A
• Application Number:
  US09/181,648
• Publication Number:
  US 20010040536A1
• Time in Patent Office: 1,818 Days
• Field of Search: 345/55, 345/60, 345/63, 345/89, 345/204, 345/213, 345/98, 345/100, 345/103, 345/99, 345/68, 345/66, 345/62, 345/214, 348/441, 348/443, 348/446, 348/454, 348/455, 348/456
• US Class Current: 345/55
• CPC Class Codes: G09G 2310/0213 controlling the sequence of the scanning lines with respect to the patterns to be displayed, e.g. to save power
• CPC Class Codes: G09G 2310/0227 related to multiple interlacing, i.e. involving more fields than just one odd field and one even field
• CPC Class Codes: G09G 2310/0267 Details of drivers for scan electrodes, other than drivers for liquid crystal, plasma or OLED displays
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/2932 Addressed by writing selected cells that are in an OFF state

Abstract

A display has a panel, and first and second electrodes. The first and second electrodes define a matrix of cells on the panel. The second electrodes, which correspond to lines of the cells, are scanned to select the cell lines one by one. The first electrodes are driven to set display data for a selected one of the cell lines. The display also has a sequence setting unit for setting sequences of scanning the second electrodes, and a sequence selection unit for selecting one of the sequences that minimizes the current and power consumption of a first-electrode driver without deteriorating the quality of the displayed images.

Claims

1. A display having a panel, and first and second electrodes, the first and second electrodes defining a matrix of cells on the panel, the second electrodes, which correspond to lines of the cells, being scanned to select cell lines, the first electrodes being driven to set display data for a selected one of the cell lines, wherein said display comprises:

a sequence setting unit setting a plurality of sequences of scanning the second electrodes;

a difference detection unit detecting differences between display data set for the cell lines;

an upper limit setting unit setting an upper limit; and

a sequence selection unit selecting one of the sequences that suppresses the differences below the upper limit.

2. A display as claimed in claim 1, wherein the sequences are set based on powers of two.

3. A display as claimed in claim 1, wherein:

said sequence setting unit divides the second electrodes into blocks and sets sequences of scanning the second electrodes block by block; and

said sequence selection unit selects one of the sequences in each of the blocks.

4. A display as claimed in claim 1, wherein said display further comprises:

an address driver driving the addressing electrodes;

a current/power value detection unit detecting a current or power value of said address driver; and

a sequence changing unit changing a sequence of scanning the second electrodes.

5. A display as claimed in claim 4, wherein said display further comprises:

a current/power value evaluation unit evaluating a current or power value of said address driver according to display data set for the cell lines so that one of the sequences that minimizes the current or power value is selected.

6. A display as claimed in claim 4, wherein said display further comprises:

a reference value setting unit setting a reference value so that one of the sequences that suppresses the current or power value to below the reference value is selected.

7. A display as claimed in claim 4, wherein said display further comprises:

a current/power value evaluation unit evaluating a current or power value of said address driver according to display data set for the cell lines; and

a reference value setting unit setting a reference value so that one of the sequences that suppresses the current or power value to below the reference value is selected.

8. A display as claimed in claim 4, wherein said display further comprises:

a current/power value evaluation unit evaluating a current or power value of said address driver beforehand according to display data set for the cell lines; and

a reference value setting unit setting a reference value so that one of the sequences that suppresses the current or power value to below the reference value is selected.

9. A display as claimed in claim 1, wherein said display further comprises:

a display data supplying unit supplying display data line by line to the first electrodes according to the selected sequence of scanning the second electrodes.

10. A display as claimed in claim 1, wherein said display is a plasma display, a frame of display data is divided into a plurality of sub-frames that are selectively combined to display gradations, and each of the sub-frames at least includes an addressing period and a sustain period.

11. A display as claimed in claim 10, wherein the panel is a three-electrode surface-discharge alternating-current plasma display panel having third electrodes that run in parallel with the second electrodes and applying an alternating voltage to the second and third electrodes to repeat a sustain discharge.

12. A display as claimed in claim 1, wherein the first electrodes are addressing electrodes, and the second electrodes are scan electrodes.

13. A display having a panel, and first and second electrodes, the first and second electrodes defining a matrix of cells on the panel, the second electrodes, which correspond to lines of the cells, being scanned to select cell lines, the first electrodes being driven to set display data for a selected one of the cell lines, wherein said display comprises:

a difference detection unit detecting differences between display data set for the cell lines;

an upper limit setting unit setting an upper limit; and

a sequence setting unit optionally setting a variable sequence of scanning the second electrodes that suppresses the differences below the upper limit.

14. A display as claimed in claim 13, wherein said sequence setting unit divides the second electrodes into blocks and sets a sequence of scanning the second electrodes in each of the blocks.

15. A display as claimed in claim 13, wherein said display further comprises:

an address driver driving the addressing electrodes;

a current/power detection unit detecting a current or power value of said address driver; and

a sequence changing unit changing a sequence of scanning the second electrodes to minimize the current or power value.

16. A display as claimed in claim 15, wherein said display further comprises:

a current/power evaluation unit evaluating a current or power value of said address driver according to display data set for the cell lines so that the second electrodes are scanned in a sequence to minimize the current or power value.

17. A display as claimed in claim 15, wherein said display further comprises:

a reference value setting unit setting a reference value so that the second electrodes are scanned in a sequence to suppress the current or power value to below the reference value.

18. A display as claimed in claim 15, wherein said display further comprises:

a current/power evaluation unit evaluating a current or power value of said address driver according to display data set for the cell lines; and

a reference value setting unit setting a reference value so that the second electrodes are scanned in a sequence to suppress the current or power value to below the reference value.

19. A display as claimed in claim 15, wherein said display further comprises:

a current/power evaluation unit evaluating a current or power value of said address driver beforehand according to display data set for the cell lines; and

a reference value setting unit setting a reference value so that the second electrodes are scanned in a sequence to suppress the current or power value to below the reference value.

20. A display as claimed in claim 13, wherein said display further comprises:

a display data supplying unit supplying display data line by line to the first electrodes according to the determined sequence of scanning the second electrodes.

21. A display as claimed in claim 13, wherein said display is a plasma display, a frame of display data is divided into a plurality of sub-frames that are selectively combined to display gradations, and each of the sub-frames at least includes an addressing period and a sustain period.

22. A display as claimed in claim 21, wherein the panel is a three-electrode surface-discharge alternating current plasma display panel having third electrodes that run in parallel with the second electrodes and applying an alternating voltage to the second and third electrodes to repeat a sustain discharge.

23. A display as claimed in claim 13, wherein the first electrodes are addressing electrodes, and the second electrodes are scan electrodes.

24. A display having a panel, a plurality of addressing electrodes, and a plurality of scan electrodes, the addressing and scan electrodes defining a matrix of cells on the panel, the scan electrodes, which correspond to lines of the cells, being scanned according to a determined order, the addressing electrodes being driven to set display data for a selected one of the cell lines, said display comprising:

a sequence setting unit determining a plurality of different scanning orders for scanning the scan electrodes, each scanning order providing a different power consumption of a driver driving the addressing electrodes; and

a sequence selection unit selecting one of the scanning orders providing a least power consumption.

25. A display having a panel, and addressing electrodes and scan electrodes, the addressing electrodes and the scan electrodes defining a matrix of cells on the panel, the scan electrodes, which correspond to lines of the cells, being scanned to select cell lines, the addressing electrodes being driven to set display data for a selected one of the cell lines, wherein said display comprises:

a sequence setting unit setting a plurality of sequences of scanning the scan electrodes;

an address driver driving the addressing electrodes;

a current/power value detection unit detecting a current or power value of said address driver;

a sequence selection unit selecting one of the sequences based on power consumption of the panel; and

a sequence changing unit changing a sequence of scanning the scan electrodes.

26. A display as claimed in claim 25, wherein said display further comprises:

a current/power value evaluation unit evaluating a current or power value of said address driver according to display data set for the cell lines so that one of the sequences that minimizes the current or power value is selected.

27. A display as claimed in claim 25, wherein said display further comprises:

a reference value setting unit setting a reference value so that one of the sequences that suppresses the current or power value below the reference value is selected.

28. A display as claimed in claim 25, wherein said display further comprises:

a current/power value evaluation unit evaluating a current or power value of said address driver according to display data set for the cell lines; and

a reference value setting unit setting a reference value so that one of the sequences that suppresses the current or power value below the reference value is selected.

29. A display as claimed in claim 25, wherein said display further comprises:

a current/power value evaluation unit evaluating a current or power value of said address driver beforehand according to display data set for the cell lines; and

a reference value setting unit setting a reference value so that one of the sequences that suppresses the current or power value below the reference value is selected.

30. A display as claimed in claim 25, wherein said display further comprises:

a display data supplying unit supplying display data line by line to the addressing electrodes according to the selected sequence of scanning the scan electrodes.

31. A display having a panel, and addressing electrodes and scan electrodes, the addressing electrodes and the scan electrodes defining a matrix of cells on the panel, the scan electrodes, which correspond to lines of the cells, being scanned to select cell lines, the addressing electrodes being driven to set display data for a selected one of the cell lines, wherein said display comprises:

an address driver driving the addressing electrodes;

a current/power detection unit detecting a current or power value of said address driver;

a sequence setting unit optionally setting a variable sequence of scanning the scan electrodes based on power consumption of the panel; and

a sequence changing unit changing a sequence of scanning the scan electrodes to minimize the current or power value.

32. A display as claimed in claim 31, wherein said display further comprises:

a current/power evaluation unit evaluating a current or power value of said address driver according to display data set for the cell lines so that the scan electrodes are scanned in a sequence to minimize the current or power value.

33. A display as claimed in claim 31, wherein said display further comprises:

a reference value setting unit setting a reference value so that the scan electrodes are scanned in a sequence to suppress the current or power value below the reference value.

34. A display as claimed in claim 31, wherein said display further comprises:

a current/power evaluation unit evaluating a current or power value of said address driver according to display data set for the cell lines; and

a reference value setting unit setting a reference value so that the scan electrodes are scanned in a sequence to suppress the current or power value below the reference value.

35. A display as claimed in claim 31, wherein said display further comprises:

a current/power evaluation unit evaluating a current or power value of said address driver beforehand according to display data set for the cell lines; and

a reference value setting unit setting a reference value so that the scan electrodes are scanned in a sequence to suppress the current or power value below the reference value.

36. A display as claimed in claim 31, wherein said display further comprises:

a display data supplying unit supplying display data line by line to the addressing electrodes according to the determined sequence of scanning the scan electrodes.