ORGANIC LIGHT-EMITTING DISPLAY AND METHOD FOR DRIVING THE SAME

• US 20170098407A1
• Filed: 12/29/2015
• Published: 04/06/2017
• Est. Priority Date: 10/02/2015
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Jeong, Jaehyeong, Kim, Seonggyun
• Granted Patent: US 10,032,405 B2
• Time in Patent Office: Days
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• 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 2310/0286 Details of a shift registers arranged for use in a driving circuit
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2320/0295 by monitoring each display pixel
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2051 with use of a spatial dither pattern
• 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 3/3275 Details of drivers for data electrodes

Abstract

An organic light-emitting display device and a method for driving the same are provided. The organic light-emitting display device analyzes input image data in unit of a window mask to detect a halftone data block, adjusts a voltage corresponding to grayscale 0 of center data disposed at the center of the halftone data block to a voltage higher than 0V, and adjusts the voltage corresponding to grayscale 0 in a data block other than the halftone data block to 0V, such that a data voltage swing width at low grayscales can be reduced so as to prevent voltage drop in pixels, thereby improving picture quality.

Claims

1. An organic light-emitting display device including a plurality of pixels each having a driving element for controlling current of an organic light-emitting diode (OLED) according to a gate-source voltage of the driving element, comprising:

a data modulation module that analyzes input image data in units of a window mask to detect a halftone data block, adjusts a voltage corresponding to grayscale 0 of center data disposed at a center of the halftone data block to a voltage higher than 0V, and adjusts the voltage corresponding to grayscale 0 in a data block other than the halftone data block to 0V,

wherein the halftone data block is a data block in which center data of the window mask has grayscale 0 and a number of grayscales higher than 0 exceeds a predetermined threshold value in neighbor data of the center data,

wherein a reference voltage higher than 0V is supplied to a source of the driving element, and the voltage corresponding to grayscale 0 is supplied to a gate of the driving element.

2. The organic light-emitting display device of claim 1, wherein the voltage corresponding to grayscale 0 in the halftone data block is adjusted to a higher level within a voltage range in which the driving element is controlled to be turned off.

3. The organic light-emitting display device of claim 1, wherein the voltage corresponding to grayscale 0 in the halftone data block is selected within a voltage range from 0V to the reference voltage.

4. The organic light-emitting display device of claim 1, wherein the data block other than the halftone data block is a data block in which the number of grayscales higher than 0 in neighbor data of center data of the window mask is less than the threshold value when the grayscale of the center data of the window mask is 0 or higher than 0.

5. The organic light-emitting display device of claim 1, wherein the data modulation module comprises a first data compensation unit that adjusts the voltage corresponding to grayscale 0 to a higher level by adding a first compensation value to data corresponding to grayscale 0.

6. The organic light-emitting display device of claim 5, wherein the first compensation value varies with the number of higher grayscales in the halftone data block.

7. The organic light-emitting display device of claim 5, wherein the voltage corresponding to grayscale 0 increases in proportion to the number of higher grayscales in the halftone data block.

8. The organic light-emitting display device of claim 5, wherein the voltage corresponding to grayscale 0 is highest when the number of higher grayscales in the halftone data block is half the number of pieces of data in the window mask.

9. The organic light-emitting display device of claim 4, wherein the data block other than the halftone data block includes a data block in a dither pattern representing decimal grayscales less than 1.

10. The organic light-emitting display device of claim 1, further comprising a data driver for outputting a data voltage in a range increased by the reference voltage.

11. A method for driving an organic light-emitting display device including a plurality of pixels each having a driving element for controlling current of an organic light-emitting diode (OLED) according to a gate-source voltage of the driving element, the method comprising:

analyzing input image data in units of a window mask to detect a halftone data block;

adjusting a voltage corresponding to grayscale 0 of center data disposed at a center of the halftone data block to a voltage higher than 0V; and

adjusting the voltage corresponding to grayscale 0 in a data block other than the halftone data block to 0V,

wherein the halftone data block is a data block in which center data of the window mask has grayscale 0 and a number of grayscales higher than 0 exceeds a predetermined threshold value in neighbor data of the center data,

wherein a reference voltage higher than 0V is supplied to a source of the driving element, and the voltage corresponding to grayscale 0 is supplied to a gate of the driving element.

12. The method of claim 11, wherein the adjusting the voltage corresponding to grayscale 0 in the halftone data block includes adjusting the voltage to a higher level within a voltage range in which the driving element is controlled to be turned off.

13. The method of claim 11, wherein the adjusting the voltage corresponding to grayscale 0 in the halftone data block includes selecting a voltage within a range from 0V to the reference voltage.

14. The method of claim 11, wherein the adjusting the voltage corresponding to grayscale 0 to a voltage higher than 0V includes adding a first compensation value to data corresponding to grayscale 0.

15. The method of claim 14, wherein the first compensation value varies with the number of higher grayscales in the halftone data block.

16. The method of claim 15, wherein the voltage corresponding to grayscale 0 increases in proportion to the number of higher grayscales in the halftone data block.

17. The method of claim 15, wherein the voltage corresponding to grayscale 0 is highest when the number of higher grayscales in the halftone data block is half the number of pieces of data in the window mask.

18. The method of claim 11, wherein the data block other than the halftone data block includes a data block in a dither pattern representing decimal grayscales less than 1.

19. The method of claim 11 further comprising outputting a data voltage in a range increased by the reference voltage.