Light emitting display device and method of driving the same

• US 20060244697A1
• Filed: 04/28/2006
• Published: 11/02/2006
• Est. Priority Date: 04/28/2005
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Mobile Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Lee, Jae Sung, Park, Young Jong
• Granted Patent: US 7,705,811 B2
• Time in Patent Office: Days
• US Class Current: 345/77
• CPC Class Codes: G09G 2300/0814 used for selection purposes, e.g. logical AND for partial update
• 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 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

A light emitting display device for controlling brightness according to peripheral light brightness and emission amount of a display region. The light emitting display device includes a display region including a pixel adapted to emit light in response to data, scan, and emission control signals, a controller for controlling brightness of the display region, a scan driver for supplying the scan signal and controlling a signal width of the emission control signal according to a signal from the controller, a data driver for transmitting the data signal corresponding to video data, the data signal being corrected using a gamma correcting signal from the controller, and a power source supply unit for supplying power to the display region. The controller outputs the gamma correcting signal corresponding to peripheral light and controls an amount of current supplied to the display region according to a sum of the video data in one frame.

Claims

1. A light emitting display device comprising:

a display region including a pixel adapted to emit light in response to a data signal, a scan signal, and an emission control signal;

a controller for controlling brightness of the display region;

a scan driver for supplying the scan signal and for controlling a signal width of the emission control signal in accordance with a signal output from the controller;

a data driver for supplying the data signal corresponding to video data, the data signal being corrected using a gamma correcting signal output from the controller; and

a power source supply unit for supplying power to the display region,

wherein the controller outputs the gamma correcting signal corresponding to peripheral light and controls an amount of current supplied to the display region in accordance with a sum of the video data in one frame.

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

a brightness controller for selecting a gamma correcting value in accordance with brightness of the peripheral light to control the data signal using the gamma correcting signal corresponding to the gamma correcting value; and

an emission controller for controlling the amount of current supplied to the display region in accordance with the sum of the video data.

3. The light emitting display device as claimed in claim 2, wherein the brightness controller comprises:

an optical sensor for outputting an analog sense signal corresponding to the brightness of the peripheral light;

an A/D converter for converting the analog sense signal to a digital sense signal;

a counter for counting a predetermined number in one frame to generate a counting signal corresponding to the counted number;

a conversion processor for outputting a control signal corresponding to the digital sense signal and the counting signal;

a register generator for dividing the brightness of the peripheral light into a plurality of steps to store a plurality of register set values corresponding to the respective steps;

a first selector for selecting one register set value among the plurality of register set values stored in the register generator in response to the control signal set by the conversion processor to output the one register set value; and

a gamma correcting circuit for generating the gamma correcting signal in accordance with the control signal of the conversion processor.

4. The light emitting display device as claimed in claim 3, wherein the brightness controller comprises a second selector for controlling on and off of the brightness controller.

5. The light emitting display device as claimed in claim 3, wherein the data signal is controlled in accordance with the gamma correcting signal output from the brightness controller.

6. The light emitting display device as claimed in claim 3, wherein the gamma correcting circuit comprises:

an amplitude control register for controlling an upper level data voltage and a lower level data voltage in accordance with register set bits;

a slope control register for selecting intermediate level data voltages in accordance with the register set bits to control gamma curves;

a first selector for selecting the upper level data voltage in accordance with the register set bits set by the amplitude control register;

a second selector for selecting the lower level data voltage in accordance with the register set bits set by the amplitude control register;

third, fourth, fifth and sixth selectors for outputting the intermediate level data voltages in accordance with the register set bits set by the slope control register; and

a data voltage amplifier for outputting a plurality of data voltages corresponding to plurality of gray scale levels to be displayed.

7. The light emitting display device as claimed in claim 2, wherein the emission controller comprises:

a data adder for summing the video data in one frame to generate frame data;

a look-up table for storing information on brightness control of the display region in accordance with a magnitude of the frame data; and

a brightness control driver for outputting a brightness control signal in accordance with information stored in the look-up table to control a ratio between an emission period and a non-emission period of the emission control signal.

8. The light emitting display device as claimed in claim 7, wherein the look-up table maintains the ratio of the emission control signal corresponding to upper 5-bit values of the frame data in one frame.

9. The light emitting display device as claimed in claim 7, wherein the look-up table is applied to a current frame based on information on an immediately previous frame.

10. The light emitting display device as claimed in claim 9, wherein the look-up table stores information corresponding to R, G, and B electroluminescent (EL) devices.

11. The light emitting display device as claimed in claim 7, wherein the data adder generates the frame data with respect to the R, G, and B EL devices.

12. The light emitting display device as claimed in claim 7, wherein the ratio between the emission period and the non-emission period of the display region is determined in accordance with the magnitude of the frame data.

13. The light emitting display device as claimed in claim 1, wherein the gamma correcting signal is controlled in accordance with a sense signal corresponding to the peripheral light to control brightness of the pixel.

14. The light emitting display device as claimed in claim 1, wherein a ratio between an emission period and a non-emission period of the emission control signal decreases as a magnitude of the sum of the video data increases.

15. The light emitting display device as claimed in claim 14, wherein the ratio between the emission period and the non-emission period of the emission control signal is not decreased when a ratio between an area of the display region that emits light and a total area of the display region is less than a predetermined ratio.

16. The light emitting display device as claimed in claim 14, wherein the ratio between the emission period and the non-emission period of the emission control signal is not decreased below a predetermined ratio.

17. A method of driving a light emitting display device that emits light in response to a current that flows through a display region, the method comprising:

controlling a data signal corresponding to video data in response to brightness of peripheral light;

generating frame data by summing the video data in one frame; and

controlling an amount of the current transmitted to the display region in accordance with the frame data.

18. The method as claimed in claim 17, wherein controlling the data signal comprises selecting a gamma correcting value in accordance with the brightness of the peripheral light to correct the data signal.

19. The method as claimed in claim 17, wherein controlling the amount of current comprises controlling an emission time of the display region in accordance with a magnitude of the frame data to control the amount of current transmitted to the display region.

20. The method as claimed in claim 19, wherein a look-up table that stores an emission time in accordance with the magnitude of the frame data is used to control the amount of the current transmitted to the display region.

21. The method as claimed in claim 20, wherein the look-up table stores the emission time using upper bits of the frame data.