Active matrix display device, method for driving the same, and electronic device

• US 20060267889A1
• Filed: 05/08/2006
• Published: 11/30/2006
• Est. Priority Date: 05/20/2005
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kimura, Hajime
• Granted Patent: US 8,847,861 B2
• Time in Patent Office: Days
• US Class Current: 345/84
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• CPC Class Codes: G09G 2310/0221 with use of split matrices G09G3/3644 and G09G3/3666 take precedence
• CPC Class Codes: G09G 2320/10 Special adaptations of display systems for operation with variable images
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• CPC Class Codes: G09G 3/3275 Details of drivers for data electrodes
• CPC Class Codes: G09G 5/395 Arrangements specially adapted for transferring the contents of the bit-mapped memory to the screen G09G5/399 takes precedence
• CPC Class Codes: G09G 5/399 using two or more bit-mapped memories, the operations of which are switched in time, e.g. ping-pong buffers

Abstract

An object of the invention is to provide a display device which can reduce the number of times signal writing to a pixel is carried out and power consumption. A display device which can reduce the number of times signal writing to a pixel is carried out and power consumption can be provided. According to an active matrix display device of the invention, in the case a signal to be written to a pixel row is identical with a signal stored in the pixel row, the scan line driver circuit does not output a selecting pulse to a scan line corresponding to the pixel row, and the signal line driver circuit makes the signal lines in a floating state or keeps without changing the state of the signal line from the previous state.

Claims

1. An active matrix display device comprising:

a pixel portion which includes a plurality of pixels, a plurality of signal lines and a plurality of scan lines;

a signal line driver circuit which is connected to the signal lines; and

a scan line driver circuit which is connected to the scan lines,

wherein the scan line driver circuit does not output a selecting pulse to select a pixel row to a scan line corresponding to a pixel row when a signal to be written to the pixel row is identical with a signal stored in the pixel row, and the signal line driver circuit puts a makes the signal lines in a floating state when a signal to be written to the pixel row is identical with a signal stored in the pixel row.

2. An active matrix display device according to claim 1, wherein the scan line driver circuit comprises an output control circuit which controls whether or not a selecting pulse is output to a scan line.

3. An active matrix display device according to claim 1, wherein the signal line driver circuit comprises an output control circuit which controls whether or not a signal line is put made in a floating state.

4. An active matrix display device according to claim 1, wherein inputting a video signal input to the signal line driver circuit is stopped when the signal to be written to the pixel row is identical with the signal stored in the pixel row.

5. An active matrix display device according to claim 1, wherein inputting a clock signal and an inverted clock signal input to the signal line driver circuit is stopped when the signal to be written to the pixel row is identical with the signal stored in the pixel row.

6. An electronic device comprising the active matrix display device according to claim 1 in a display portion.

7. An active matrix display device comprising:

a pixel portion which includes a plurality of pixels, a plurality of signal lines and a plurality of scan lines;

a signal line driver circuit which is connected to the signal lines; and

a scan line driver circuit which is connected to the scan lines,

wherein the scan line driver circuit does not output a selecting pulse to select a pixel row to a scan line corresponding to a pixel row when a signal to be written to the pixel row is identical with a signal stored in the pixel row, and the signal line driver circuit outputs a signal to a the signal lines without changing the state of the previous state when a signal to be written to the pixel row is identical with a signal stored in the pixel row.

8. An active matrix display device according to claim 7, wherein the scan line driver circuit comprises an output control circuit which controls whether or not a selecting pulse is output to a scan line.

9. An active matrix display device according to claim 7, wherein inputting a video signal input to the signal line driver circuit is stopped when the signal to be written to the pixel row is identical with the signal stored in the pixel row.

10. An active matrix display device according to claim 7, wherein inputting a clock signal and an inverted clock signal input to the signal line driver circuit is stopped when the signal to be written to the pixel row is identical with the signal stored in the pixel row.

11. An electronic device comprising the active matrix display device according to claim 7 in a display portion.

12. A method for driving an active matrix display device, the display device including:

a pixel portion which includes a plurality of pixels, a plurality of signal lines and a plurality of scan lines;

a signal line driver circuit which is connected to the signal lines; and

a scan line driver circuit which is connected to the scan lines,

said method comprising the steps of;

comparing a signal to be written to a pixel row with a signal stored in the pixel row; and

stopping selecting the pixel row while putting making the signal lines in a floating state when the signal to be written to the pixel row is identical with the signal stored in the pixel row.

13. A method for driving an active matrix display device according to claim 12, wherein the scan line driver circuit comprises an output control circuit which controls whether or not a selecting pulse is output to a scan line.

14. A method for driving an active matrix display device according to claim 12, wherein the signal line driver circuit comprises an output control circuit which controls whether or not a signal line is put made in a floating state.

15. A method for driving an active matrix display device according to claim 12, wherein inputting a video signal input to the signal line driver circuit is stopped when the signal to be written to the pixel row is identical with the signal stored in the pixel row.

16. A method for driving an active matrix display device according to claim 12, wherein inputting a clock signal and an inverted clock signal input to the signal line driver circuit is stopped when the signal to be written to the pixel row is identical with the signal stored in the pixel row.

17. An electronic device comprising an active matrix display device using the method for driving according to claim 12 in a display portion.

18. A method for driving an active matrix display device, the display device including:

a pixel portion which includes a plurality of pixels, a plurality of signal lines and a plurality of scan lines;

a signal line driver circuit which is connected to the signal lines; and

a scan line driver circuit which is connected to the scan lines,

said method comprising the steps of;

comparing a signal to be written to a pixel row with a signal stored in the pixel row; and

stopping selecting the pixel row while outputting a signal to a the signal lines without changing the state of the previous state when the signal to be written to a pixel row is identical with the signal stored in the pixel row.

19. A method for driving an active matrix display device according to claim 18, wherein the scan line driver circuit comprises an output control circuit which controls whether or not a selecting pulse is output to a scan line.

20. A method for driving an active matrix display device according to claim 18, wherein inputting a video signal input to the signal line driver circuit is stopped when the signal to be written to the pixel row is identical with the signal stored in the pixel row.

21. A method for driving an active matrix display device according to claim 18, wherein inputting a clock signal and an inverted clock signal input to the signal line driver circuit is stopped when the signal to be written to the pixel row is identical with the signal stored in the pixel row.

22. An electronic device comprising an active matrix display device using the method for driving according to claim 18 in a display portion.