Display device and control method thereof

• US 20070164937A1
• Filed: 07/07/2006
• Published: 07/19/2007
• Est. Priority Date: 07/08/2005
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Beohm-rock, Yun, Young-soo, Jung, Kwang-chui, Goh, Joan-chul
• Granted Patent: US 7,742,029 B2
• Time in Patent Office: Days
• US Class Current: 345/76
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• 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 3/3233 with pixel circuitry controlling the current through the light-emitting element
• 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

A display device with improved brightness and a method of controlling the display device are presented. The display device includes a driving transistor, a pixel electrode electrically connected to the driving transistor, a detecting transistor detecting a magnitude of an electric signal transferred from the driving transistor to the pixel electrode, and a controller. The controller regulates a data voltage applied to the pixel electrode based on a difference between the detected electric signal and a predetermined reference level. The display device achieves improved homogeneity of brightness by compensating for any deterioration of TFTs.

Claims

1. A display device comprising:

a driving transistor;

a pixel electrode electrically connected to the driving transistor;

a detecting transistor detecting a magnitude of an electric signal transferred from the driving transistor to the pixel electrode; and

a controller regulating a data voltage applied to the pixel electrode based on a difference between the detected electric signal and a predetermined reference level.

2. The display device according to claim 1, further comprising:

a driving voltage line applying the driving voltage to the driving transistor;

a switching transistor connected to a gate electrode of the driving transistor;

a data line applying the data voltage to the switching transistor; and

a gate line applying a gate on voltage to the switching transistor.

3. The display device according to claim 1, further comprising a detecting line connected to the detecting transistor.

4. The display device according to claim 3, wherein the detecting line extends substantially parallel to one of the driving voltage line and the data line.

5. The display device according to claim 2, wherein the gate line is a first gate line and a gate electrode of the detecting transistor is connected to a second gate line.

6. The display device according to claim 2, wherein the controller comprises a memory storing a table of reference levels that correspond to a range of voltages including the data voltage, and wherein the controller determines a compensation voltage based on a difference between the data voltage that corresponds to a magnitude of the detected electrical signal and a voltage corresponding to the reference level.

7. The display device according to claim 6, wherein the controller applies the compensation voltage to the data line.

8. The display device according to claim 6, wherein the controller determines the compensation voltage if the difference is outside a predetermined range of values.

9. The display device according to claim 1, wherein the electric signal is a measurement of either a voltage or a current.

10. The display device according to claim 1, wherein the predetermined range comprises an error range in which the detected electric signal is substantially same as the predetermined reference level.

11. A display device comprising:

a pixel electrode;

a detecting transistor detecting a pixel current applied to the pixel electrode; and

a controller regulating a pixel voltage applied to the pixel electrode based on a difference between the pixel current and a predetermined reference level.

12. The display device according to claim 11, wherein the controller comprises a memory storing a table of reference levels including a reference level that corresponds to the pixel current, and wherein the controller determines a compensation voltage based on a difference between the pixel voltage that corresponds to a magnitude of the detected pixel current and a voltage corresponding the reference level.

13. The display device according to claim 12, wherein the controller applies the compensation voltage to the pixel electrode.

14. The display device according to claim 11, wherein the predetermined range comprises an error range in which the detected electric signal is substantially same as the predetermined reference level.

15. A method of controlling a display device, the method comprising:

turning on a driving transistor;

detecting an electric signal transmitted from the driving transistor to a pixel electrode;

comparing the detected electric signal with a predetermined reference level; and

regulating a data voltage applied to the pixel electrode based on a difference between the electric signal and the predetermined reference level.

16. The method according to claim 15, wherein regulating the data voltage comprises determining a compensation voltage corresponding to a difference between the data voltage that corresponds to a magnitude of the detected electric signal and a voltage that corresponds to the reference level.

17. The method according to claim 16, further comprising applying the compensation voltage to the pixel electrode.

18. The method according to claim 15, wherein the electric signal is a measurement of either a voltage or a current.