ORGANIC LIGHT EMITTING DISPLAY DEVICE AND DRIVING METHOD THEREOF

• US 20090040151A1
• Filed: 07/10/2008
• Published: 02/12/2009
• Est. Priority Date: 08/08/2007
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung SDI Company Limited
• Inventors: LEE, JAE-SUNG
• Granted Patent: US 8,427,399 B2
• Time in Patent Office: Days
• US Class Current: 345/77
• CPC Class Codes: G09G 2320/02 Improving the quality of display appearance
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• 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 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 3/3225 using an active matrix

Abstract

A controller to reduced power consumption and/or improve outdoor visibility of an organic light emitting display device, and an organic light emitting display device includes the same. The organic light emitting display device including: a light sensor to generate light sensing signals corresponding to an external light intensity; an image judging unit to generate image judging signals, by judging whether images generated by the data signals are moving images or still images; a signal processor to compare the light sensing signals with preset reference values, to generate selection signals, and to modify image data accordingly; a frame memory to store the image data from the signal processor; and a reset signal driver to reset the frame memory according to the image judging signals and the selection signals.

Claims

1. An organic light emitting display device, comprising:

a pixel unit including scan lines to transfer scan signals, data lines to transfer data signals, and pixels to represent image data, coupled to the scan lines and the data lines;

a light sensor to generate light sensing signals corresponding to an external light intensity of an environment of the display device;

an image judging unit to generate image judging signals, according to whether the data signals relate to moving images or still images;

a signal processor to compare the light sensing signals with reference values to generate selection signals, and to modify the image data according to the selection signals;

a frame memory to store the image data output from the signal processor;

a reset signal driver to generate reset signals to reset the frame memory, according to the image judging signals and the selection signals;

a scan driver to generate the scan signals, and to sequentially output the scan signals to the scan lines; and

a data driver to generate the data signals, and to output the data signals to the data lines.

2. The organic light emitting display device as claimed in claim 1, wherein the signal processor comprises:

a comparator to compare the light sensing signals with the reference values, and to generate the selection signals, which relate to one of at least two modes, according to the comparison;

a first calculator to generate pixel saturation data corresponding to the image data;

a second calculator to modify the image data, according to the pixel saturation data and the selection signals; and

a memory to store the image data or the modified image data; and

a controller to control the first calculator, the second calculator, and the memory, and to output the image data to the first calculator or the memory, according to the selection signals.

3. The organic light emitting display device as claimed in claim 2, further comprising a saturation change matrix that is referenced by the first calculator to generate the pixel saturation data.

4. The organic light emitting display device as claimed in claim 3, wherein:

the pixels comprise sub-pixels;

the first calculator uses the saturation change matrix and sub-pixel data of the image data, to calculate target saturation data; and

the first calculator generates the pixel saturation data using the target saturation data.

5. The organic light emitting display device as claimed in claim 2, further comprising a reference lookup table comprising a first saturation and brightness lookup table that is part referenced by the second calculator to modify the image data.

16. The organic light emitting display device as claimed in claim 4, wherein the first calculator calculates the target saturation data with respect to each of the sub pixels.

17. The organic light emitting display device as claimed in claim 1, wherein the signal processor modifies pixel saturation and/or brightness values of image data, with respect to each of the pixels.

18. The organic light emitting display device as claimed in claim 2, wherein the image data is output from the controller to the first calculator, and then to the second calculator, or from the controller to the memory.

19. The organic light emitting display device as claimed in claim 2, wherein the modified image data is output from the second calculator to the memory.

6. An organic light emitting display device comprising:

a pixel unit comprising scan lines to transfer scan signals, data lines to transfer data signals, and pixels to represent image data, coupled to the scan lines and the data lines;

a switch unit to generate switch signals;

a signal processor to generate selection signals when the switch signals are received from the switch unit, and to modify the image data according to the selection signals;

a frame memory to store the image data when the image data is received from the signal processor;

a reset signal driver to generate reset signals to reset the frame memory, when the reset signal driver receives the switch signals;

a scan driver sequentially to generate the scan signals, and to output the scan signals to the scan lines; and

a data driver to generate the data signals, and to output the data signals to the data lines.

7. The organic light emitting display device as claimed in claim 6, wherein the signal processor comprises:

a first calculator to generate pixel saturation data corresponding to the image data;

a second calculator to modify the image data, according to the pixel saturation data and the selection signals; and

a memory storing the image data or the modified data transferred from the second calculator; and

a controller to control the first calculator, the second calculators, and the memory, and to output the image data to the memory or the first calculator, according to the switch signals.

8. The organic light emitting display device as claimed in claim 7, further comprising a saturation change matrix that is referenced by the first calculator to generate the pixel saturation data.

9. The organic light emitting display device as claimed in claim 8, wherein:

the pixels comprise sub-pixels;

the first calculator uses the saturation change matrix and sub-pixel data of the image data, to calculate target saturation data; and

the first calculator generates the pixel saturation data using the target saturation data.

10. The organic light emitting display device as claimed in claim 7, further comprising a reference lookup table comprising a first saturation and brightness lookup table that is referenced by the second calculator, to modify the image data.

11. A driving method of an organic light emitting display device, comprising:

storing image data in a frame memory;

resetting the frame memory to erase the image data; and

storing modified image data in the reset frame memory,

wherein the modified image data corresponds to the image data, and comprises modified pixel saturation and/or brightness values of a still image included in the image data.

12. The method as claimed in claim 11, wherein the modified image data is produced according to a signal output from a light sensor, according to the luminance of an environment in which the display device is disposed.

13. The method as claimed in claim 11, wherein the modified image data is produced according to a signal output from a user operated switch.

14. The method as claimed in claim 11, wherein the modified image data is produced according to a signal output from an image judging unit, when the image judging unit determines that the image data includes the still image.

15. The method as claimed in claim 11, wherein the modified image data is produced according to a signal is output from a user operated switch, in response to the luminance of an environment in which the display device is disposed.