Organic light emitting display device including signal processor for modifying image data and driving method thereof

• US 8,427,399 B2
• Filed: 07/10/2008
• Issued: 04/23/2013
• Est. Priority Date: 08/08/2007
• Status: Expired due to Fees

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Lee, Jae-sung
• Primary Examiner(s): Nguyen, Chanh
• Assistant Examiner(s): Park, Sanghyuk
• Application Number:
  US12/170,765
• Publication Number:
  US 20090040151A1
• Time in Patent Office: 1,748 Days
• Field of Search: 345/36, 345/39, 345/45, 345 76- 83
• US Class Current: 345/76
• 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 display unit including scan lines to transfer scan signals, data lines to transfer data signals, and pixels to represent image data organized in frames, the pixels being 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 subsequent frames of the image data relate to moving images or still images, the image judging unit being configured to generate the image judging signals only if the image data corresponds to the 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 modified image data output from the signal processor, the frame memory being configured to

store the modified image data in units corresponding to one of the frames,

not change corresponding modified image data of the subsequent frames of the image data when the subsequent frames relate to the still images, and

reload the frame memory from the signal processor output after a reset of the frame memory;

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 4, wherein the first calculator calculates the target saturation data with respect to each of the sub-pixels.

6. 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 referenced by the second calculator to modify the image data.

7. 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.

8. 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.

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

10. A driving method of an organic light emitting display device comprising a signal processor for modifying image data organized in frames, the method comprising:

generating scan signals and sequentially outputting the scan signals to scan lines;

generating data signals and outputting the data signals to data lines;

generating light sensing signals corresponding to an external light intensity of an environment of the display device;

storing modified image data output from the signal processor in a frame memory configured to store the image data in units each corresponding to one of the frames, the image data comprising first image data in a first one of the frames that relates to a still image;

generating image judging signals according to whether subsequent ones of the frames of the image data relate to moving images or still images, comprising generating the image judging signals only if the image data corresponds to the still images;

generating selection signals by comparing the light sensing signals with reference values, modifying the image data according to the selection signals, and outputting the selection signals and the modified image data from the signal processor;

not changing the first image data in the frame memory, of the subsequent ones of the frames of the image data, when the subsequent ones of the frames relate to the still image;

reloading the frame memory from the signal processor output after a reset of the frame memory;

resetting the frame memory to erase the first image data in the frame memory in a second one of the frames that relates to the still image; and

storing modified first image data in the second one of the frames,

wherein the modified first image data corresponds to the first image data, and comprises modified pixel saturation and/or brightness values of the first image data.

11. The method as claimed in claim 10, wherein the modified first image data is produced according to a signal output from a light sensor, according to a luminance of an environment in which the display device is disposed.

12. The method as claimed in claim 10, wherein the modified first image data is produced according to a signal output from an image judging unit, when the image judging unit determines that the image data relates to the still image.