Organic light emitting display device

• US 9,583,044 B2
• Filed: 04/21/2015
• Issued: 02/28/2017
• Est. Priority Date: 12/29/2014
• 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: Kim, Il Nam, Mok, Rang Kyun, Park, Won Sang, Baek, Jong In
• Primary Examiner(s): CERULLO, LILIANA P
• Application Number:
  US14/692,316
• Publication Number:
  US 20160189671A1
• Time in Patent Office: 679 Days
• US Class Current: 1/1
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0297 Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 3/3291 in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements

Abstract

An organic light emitting display device includes a display panel including red sub-pixels, green sub-pixels, first blue sub-pixels, and second blue sub-pixels. A data drive unit receives an image signal and outputs a plurality of data output signals. A demultiplexer distributes the data signals to the red sub-pixels, the green sub-pixels and either the first blue sub-pixels or both the first and second blue sub-pixels in response a drive selection signal. A control unit processes raw image data and provides an image signal to the data drive unit, and detects image data belonging to a first color gamut and a second color gamut from the image data, determines a first blue drive area belonging to the first color gamut and a mixed drive area belonging to the second color gamut, and provides the appropriate selection signal to the demultiplexer to increase efficiency and extend useful life of the display.

Claims

1. An organic light emitting display device comprising:

a display panel comprising red sub-pixels, green sub-pixels, first blue sub-pixels, and second blue sub-pixels, which are respectively connected to a plurality of scan lines and a plurality of data lines;

a scan drive unit configured to sequentially applies a plurality of scan signals to the plurality of scan lines;

a data drive unit configured to receive an image signal and output a plurality of data output signals;

a demultiplexer configured to distribute the plurality of data signals to the data lines connected to the red sub-pixels, the green sub-pixels, and the first blue sub-pixels in response to a first blue drive selection signal, or distribute the plurality of data output signals to the data lines connected to the red sub-pixels, the green sub-pixels, the first blue sub-pixels, and the second blue sub-pixels in response to a mixed drive selection signal; and

a control unit configured to process raw image data into an image signal and provide the image signal to the data drive unit,

wherein the control unit is configured to detect image data belonging to a first color gamut and a second color gamut from the image data, determine a first blue drive area comprising the image data belonging to the first color gamut and a mixed drive area comprising the image data belonging to the second color gamut, provide the first blue drive selection signal to the demultiplexer when the data output signal corresponding to the first blue drive area is provided from the data drive unit to the demultiplexer, and provide the mixed drive selection signal to the demultiplexer when the data output signal corresponding to the mixed drive area is provided from the data drive unit to the demultiplexer.

2. The organic light emitting display device of claim 1, wherein the control unit comprises an image data processing unit configured to receive the raw image data and generate the corrected image data, and a timing control unit configured to receive the corrected image data from the image data processing unit and process the corrected image data into an image signal.

3. The organic light emitting display device of claim 2, wherein the image data processing unit comprises:

a color gamut determination unit configured to detect image data belonging to the first color gamut and the second color gamut from the image data, and determine the first blue drive area including the image data belonging to the first color gamut and the mixed drive area including the image data belonging to the second color gamut; and

an image data correction unit configured to receive values for the first blue drive area and the mixed drive area from the color gamut determination unit, and correct image data belonging to the mixed drive area in the raw image data.

4. The organic light emitting display device of claim 3, wherein the image data correction unit is configured to transmit a mode selection signal, which indicates whether image data of the corrected image data belongs to the first blue drive area or the mixed drive area, to the timing control unit, and the timing control unit is configured to transmit a first blue drive selection signal or a mixed blue drive selection signal to the demultiplexer according to the received mode selection signal.

5. The organic light emitting display device of claim 4, wherein the data drive unit is configured to receive a plurality of grayscale voltages from a grayscale voltage generation unit, select at least one of the received grayscale voltages, and output the selected grayscale voltage as a data output signal.

6. The organic light emitting display device of claim 5, wherein the grayscale voltage generation unit is configured to receive a gamma selection signal provided from the timing control unit, and generate a plurality of grayscale voltages which correspond to a gamma curve in a first blue drive mode in which the red sub-pixels, the green sub-pixels, and the first blue sub-pixels are driven, or a gamma curve in a mixed blue drive mode in which the red sub-pixels, the green sub-pixels, the first blue sub-pixels, and the second blue sub-pixels are driven, depending on the received gamma selection signal.

7. The organic light emitting display device of claim 6, wherein the image data correction unit is configured to correct a grayscale value of the image data belonging to the mixed drive area in the raw image data to match the gamma curve in the first blue drive mode.

8. The organic light emitting display device of claim 7, wherein the control unit further comprises a memory, and the memory is configured to store a reference value related to the gamma curve in the first blue drive mode and the gamma curve in the mixed blue drive mode.

9. The organic light emitting display device of claim 1, further comprising a grayscale voltage generation unit configured to provide a plurality of grayscale voltages to the data drive unit,

wherein the data drive unit is configured to select at least one of the received grayscale voltages and provide the selected grayscale voltage as a data output signal to the demultiplexer.

10. The organic light emitting display device of claim 9, wherein the control unit comprises an image data processing unit configured to provide a gamma selection signal to the grayscale voltage generation unit, and a timing control unit configured to receive the raw image data and process the raw image data into the image signal.

11. The organic light emitting display device of claim 10, wherein the image data processing unit comprises:

a color gamut determination unit configured to detect image data belonging to the first color gamut and the second color gamut from the image data, and determine the first blue drive area including the image data belonging to the first color gamut and the mixed drive area including the image data belonging to the second color gamut; and

a gamma selection signal generation unit configured to receive values for the first blue drive area and the mixed drive area from the color gamut determination unit, provide a gamma selection signal corresponding to the first blue drive mode to the grayscale voltage generation unit when the data output signal corresponding to the first blue drive area in the raw image data is provided from the data drive unit to the demultiplexer, and provide a gamma selection signal corresponding to the mixed drive mode to the grayscale voltage generation unit when the data output signal corresponding to the mixed drive area in the raw image data is provided from the data drive unit to the demultiplexer.

12. The organic light emitting display device of claim 11, wherein:

when the gamma selection signal corresponding to the first blue drive mode is applied, the grayscale voltage generation unit is configured to generate a plurality of grayscale voltages, depending on the gamma curve corresponding to the grayscale value when the red sub-pixels, the green sub-pixels, and the first blue sub-pixels are driven; and

when the gamma selection signal corresponding to the mixed drive mode is applied, the grayscale voltage generation unit is configured to generate a plurality of grayscale voltages, depending on the gamma curve corresponding to the gamma value when the red sub-pixels, the green sub-pixels, the first blue sub-pixels, and the second blue sub-pixels are driven.

13. The organic light emitting display device of claim 11, wherein the image data correction unit is configured to transmit a mode selection signal, which indicates whether image data of the corrected image data belongs to the first blue drive area or the mixed drive area, to the timing control unit, and the timing control unit is configured to transmit a first blue drive selection signal or a mixed blue drive selection signal to the demultiplexer, depending on the received mode selection signal.

14. The organic light emitting display device of claim 1, wherein light emitted from the first blue sub-pixels has a color lighter than light emitted from the second blue sub-pixels.

15. The organic light emitting display device of claim 1, wherein:

the data output signal applied to the demultiplexer circuit is a signal in which a red data signal is applied to the red sub-pixels, a green data signal is applied to the green sub-pixels, and a blue data signal is applied to the first blue sub-pixels, the second blue sub-pixels, or both the first blue sub-pixels and the second blue sub-pixels; and

the red data signal, the green data signal, and the blue data signal are sequentially arranged in time.

16. The organic light emitting display device of claim 1, wherein:

the first color gamut is expressed by light emission of the red sub-pixels, the green sub-pixels, and the first blue sub-pixels; and

the first color gamut is excluded from the second color, which is expressed by light emission of the red sub-pixels, the green sub-pixels, the first blue sub-pixels, and the second blue sub-pixels.

17. The organic light emitting display device of claim 1, wherein the control unit is configured to:

detect image data belonging to the first color gamut, the second color gamut, and a third color gamut from the image data;

determine the first blue drive area comprising image data belonging to the first color gamut, the mixed drive area comprising image data belonging to the second color gamut, and a second blue drive area comprising the image data belonging to the third color gamut;

provide the first blue drive selection signal to the demultiplexer when the data output signal corresponding to the first blue drive area is provided from the data drive unit to the demultiplexer;

provide the mixed drive selection signal to the demultiplexer when the data output signal corresponding to the mixed drive area is provided from the data drive unit to the demultiplexer;

provide the second blue drive selection signal to the demultiplexer when the data output signal corresponding to the second blue drive area is provided from the data drive unit to the demultiplexer; and

distribute a plurality of data output signals to the data lines connected to the red sub-pixels, the green sub-pixels, the first blue sub-pixels, and the second blue sub-pixels.

18. The organic light emitting display device of claim 17, wherein:

the first color gamut is expressed by light emission of the red sub-pixels, the green sub-pixels, and the first blue sub-pixels;

the first color gamut is excluded from the second color gamut, which is expressed by light emission of the red sub-pixels, the green sub-pixels, the first blue sub-pixels, and the second blue sub-pixels; and

the first color gamut and the second color gamut are excluded from the third color gamut, which is expressed by light emission of the red sub-pixels, the green sub-pixels, and the second blue sub-pixels.