Matrix Addressing Method and Circuitry and Display Device Using the Same

• US 20090213042A1
• Filed: 05/09/2006
• Published: 08/27/2009
• Est. Priority Date: 05/16/2005
• Status: Active Grant

• Current Assignee: Innolux Hong Kong Holding Ltd (InnoLux Corporation)
• Original Assignee: TPO Hong Kong Holding Limited (InnoLux Corporation)
• Inventors: Furui, Yuko, Iwatsu, Akihiro, Watanabe, Hidetoshi, Hagino, Shuji
• Granted Patent: US 8,284,122 B2
• Time in Patent Office: Days
• 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 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/0407 Resolution change, inclusive of the use of different resolutions for different screen areas
• CPC Class Codes: G09G 2340/0428 Gradation resolution change
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/2044 using dithering
• CPC Class Codes: G09G 3/2051 with use of a spatial dither pattern
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3688 suitable for active matrices only
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

The invention aims at providing a matrix addressing method and circuitry and display device, which enable power savings without as little degrading the legibility of content of an image as possible. A matrix addressing method for driving pixels arranged over a display area by signals supplied to row electrodes and column electrodes arranged to cross one another. Rich-gray-scale pixel information signals (#0 to #63) are generated in a predetermined number of levels of gray scale according to original pixel information signals, while poor-gray-scale pixel information signals (#0 and #63) are generated in a smaller number of levels of gray scale than the maximum number of levels of gray scale, according to original pixel information signals, and rich-gray-scale pixels driven by the rich-gray-scale pixel information signals (#0 to #63) and poor-gray-scale pixels driven by the poor-gray-scale pixel information signals (#0 and #63) are mixed and coexist discretely in at least a part of the display area in a predetermined mixing pattern to display the same image object in a predetermined mode.

Claims

1. A matrix addressing method for driving pixels arranged over a display area by signals supplied to row electrodes and column electrodes arranged to cross one another, the method comprising the following steps of:

generating rich-gray-scale pixel information signals in a predetermined number of levels of gray scale in accordance with original pixel information signals;

generating poor-gray-scale pixel information signals in a smaller number of levels of gray scale than the predetermined number of levels of gray scale in according with original pixel information signals; and

discretely mixing rich-gray-scale pixels driven by the rich-gray-scale pixel information signals and poor-gray-scale pixels driven by the poor-gray-scale pixel information signals to coexist in at least a part of the display area in a predetermined mixing pattern to display the same image object in a predetermined mode.

2. The method as claimed in claim 1, wherein the mixing pattern and/or a ratio between the number of the rich-gray-scale pixels and the number of the poor-gray-scale pixels are/is variable.

3. The method as claimed in claim 1, wherein the poor-gray-scale pixels are driven by the poor-gray-scale pixel information signals at a lower frequency than that of the rich-gray-scale pixels.

4. The method as claimed in claim 3, wherein in driving the poor-gray-scale pixels at the lower frequency, row electrode selecting operation is performed to select only part of the row electrodes associated with the rich-gray-scale pixels while passing other part of the row electrodes associated with only the poor-gray-scale pixels.

5. The method as claimed in claim 1, wherein the poor-gray-scale pixel information signals only include a signal with a minimum driving level of the pixel and a signal with a maximum driving level of the pixel.

6. The method as claimed in claim 1, wherein gamma correction characteristics applied to the rich-gray-scale pixel information signals are variable in according with a spatial arrangement manner in the display area of the poor-gray-scale pixels driven by the poor-gray-scale pixel information signals, an input instruction or other setting.

7. The method as claimed in claim 1, wherein an arrangement of the rich-gray-scale pixels and the poor-gray-scale pixels in the display area is switched at predetermined timing or periodically.

8. The method as claimed in claim 1, wherein the poor-gray-scale pixel information signals are obtained by performing a dithering processing on the original pixel information signals.

9. A matrix addressing circuit for driving pixels arranged across a display area by signals supplied to row electrodes and column electrodes arranged to be mutually crossed, comprising:

a rich-gray-scale generating unit for generating rich-gray-scale pixel information signals in a predetermined number of levels of gray scale in accordance with original pixel information signals;

a poor-gray-scale generating unit for generating poor-gray-scale pixel information signals in a smaller number of levels of gray scale than the predetermined number of levels of gray scale in accordance with original pixel information signals; and

a mixing control unit for discretely mixing rich-gray-scale pixels driven by the rich-gray-scale pixel information signals and poor-gray-scale pixels driven by the poor-gray-scale pixel information signals to coexist in at least a part of the display area in a predetermined mixing pattern to display the same image object in a predetermined mode.

10. The circuit as claimed in claim 9, wherein the rich-gray-scale generating unit comprise a gray-scale voltage generating circuit with amplifiers respectively receiving a plurality of gray-scale voltages having gradually level-shifted values, and a selecting circuit that selects any of outputs of the amplifiers for each pixel or each predetermined display unit in accordance with a pixel information signal indicating a level of gray scale of the pixel or the display unit and outputs it as the rich-gray-scale pixel information signals, and the poor-gray-scale generating unit comprise a switch circuit which disconnects power supply to all the amplifiers or connects power supply only to a predetermined number of amplifiers corresponding to predetermined gray scale levels among the all amplifiers while disconnecting power supply to the other amplifiers in the predetermined mode, and a setting circuit for setting the selecting circuit in a condition to select either of a power supply voltage and a ground voltage and/or any of output signals of the amplifiers given the power supply in accordance with a selection control signal responsive to the original pixel information signal in the predetermined mode to output the selected one as the poor-gray-scale pixel information signal.

11. The circuit as claimed in claim 10, wherein the poor-gray-scale generating unit comprise a signal processing circuit that performs dithering processing on the original pixel information signal an output of the signal processing circuit being used as the selection control signal in the predetermined mode.

12. The circuit as claimed in claim 10, wherein the mixing control unit comprise a unit for supplying a control signal to the switch circuit and the selecting circuit in the predetermined mode to switch between one state where the selecting circuit outputs the rich-gray-scale pixel information signal and the other state where the selecting circuit outputs the poor-gray-scale pixel information signal for each scanning line or each pixel in accordance with the predetermined mixing pattern.

13. The circuit as claimed in claim 10, further comprising:

a buffer amplifier or a switch supplied with an output signal of the selecting circuit, wherein, in the predetermined mode, the buffer amplifier or switch is controlled to output the poor-gray-scale pixel information signal during a prescribed frame of a sequence consisting of a plurality of frames and to break the output of the poor-gray-scale pixel information signal in at least one remainder frame of the sequence.

14. The circuit as claimed in claim 13, comprising:

a row electrode driving unit for performing row electrode selecting operation to select only a part of the row electrodes associated with the rich-gray-scale pixels while passing other part of the row electrodes associated with only the poor-gray-scale pixels in the predetermined mode, wherein the row electrode is passed corresponding to an output breaking state of the poor-gray-scale pixel information signal.

15. The circuit as claimed in claim 10, wherein the predetermined mode includes a plurality of sub-modes, and the gray-scale voltage generating circuit is set with amplifiers to be powered for each sub-mode.

16. A display device using a matrix addressing circuit for driving pixels arranged across a display area by signals supplied to row electrodes and column electrodes arranged to be mutually crossed, the matrix addressing circuit comprising:

rich-gray-scale generating unit for generating rich-gray-scale pixel information signals in a predetermined number of levels of gray scale in accordance with original pixel information signals;

poor-gray-scale generating unit for generating poor-gray-scale pixel information signals in a smaller number of levels of gray scale than the predetermined number of levels of gray scale in accordance with original pixel information signals; and

mixing control unit coupled to the rich-gray-scale generating unit and the poor-gray-scale generating unit for discretely mixing rich-gray-scale pixels driven by the rich-gray-scale pixel information signals and poor-gray-scale pixels driven by the poor-gray-scale pixel information signals to coexist in at least a part of the display area in a predetermined mixing pattern to display the same image object in a predetermined mode.

17. The device as claimed in claim 16, wherein the rich-gray-scale generating unit comprise a gray-scale voltage generating circuit with amplifiers respectively receiving a plurality of gray-scale voltages having gradually level-shifted values, and a selecting circuit that selects any of outputs of the amplifiers for each pixel or each predetermined display unit in accordance with a pixel information signal indicating a level of gray scale of the pixel or the display unit and outputs it as the rich-gray-scale pixel information signals, and the poor-gray-scale generating unit comprise a switch circuit which disconnects power supply to all the amplifiers or connects power supply only to a predetermined number of amplifiers corresponding to predetermined gray scale levels among the all amplifiers while disconnecting power supply to the other amplifiers in the predetermined mode, and a setting circuit coupled to the selecting circuit for setting the selecting circuit in a condition to select either of a power supply voltage and a ground voltage and/or any of output signals of the amplifiers given the power supply in accordance with a selection control signal responsive to the original pixel information signal in the predetermined mode to output the selected one as the poor-gray-scale pixel information signal.

18. The device as claimed in claim 17, wherein the poor-gray-scale generating unit comprise a signal processing circuit that performs dithering processing on the original pixel information signal an output of the signal processing circuit being used as the selection control signal in the predetermined mode.

19. The device as claimed in claim 17, wherein the mixing control unit comprise a supplying circuit coupled to the switch circuit and the selecting circuit for supplying a control signal to the switch circuit and the selecting circuit in the predetermined mode to switch between one state where the selecting circuit outputs the rich-gray-scale pixel information signal and the other state where the selecting circuit outputs the poor-gray-scale pixel information signal for each scanning line or each pixel in accordance with the predetermined mixing pattern.

20. The device as claimed in claim 17, wherein the matrix addressing further comprises:

a buffer amplifier or a switch coupled to the selecting circuit and supplied with an output signal of the selecting circuit, wherein, in the predetermined mode, the buffer amplifier or switch is controlled to output the poor-gray-scale pixel information signal during a prescribed frame of a sequence consisting of a plurality of frames and to break the output of the poor-gray-scale pixel information signal in at least one remainder frame of the sequence.