ORGANIC LIGHT EMITTING DISPLAY DEVICE AND DRIVING METHOD THEREOF

• US 20110025678A1
• Filed: 02/23/2010
• Published: 02/03/2011
• Est. Priority Date: 07/29/2009
• Status: Abandoned Application

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Mobile Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Chung, Ho-Ryun
• Application Number:
  US12/710,627
• Publication Number:
  US 20110025678A1
• Time in Patent Office: Days
• US Class Current: 345/213
• 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 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• 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 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

An organic light emitting display device is disclosed. The device includes a data driver for supplying a plurality of data signals and a reset voltage to each output line during every horizontal period. The data driver is configured to selectively supply the reset signal and the reset voltage based on a comparison of the data signal input to each data line during a current horizontal period with the data signal input to the data lines during the previous horizontal period.

Claims

1. An organic light emitting display, comprising:

a data driver configured to supply a plurality of data signals and a reset voltage to each of a plurality of output lines;

a plurality of demultiplexers connected to the output lines and a plurality of data lines, each of the output lines corresponding to a plurality of the data lines, wherein each of the demultiplexers has a plurality of switching elements configured to connect each output line to the corresponding data lines;

a demultiplexer controller configured to supply a plurality of control signals and to selectively supply a reset signal to the demultiplexers, the plurality of control signals allowing the data signals of an output line to be applied to the corresponding data lines by sequentially turning on the switching elements, and the reset signal allowing the reset voltage of an output line to be applied to the corresponding data lines by simultaneously turning on the plurality of switching elements;

a scan driver configured to sequentially supply scan signals to scan lines for each of a plurality of horizontal periods; and

a plurality of pixels coupled to the data and scan lines,

wherein the reset signal is selectively supplied to the demultiplexers based at least in part on a comparison of a data signal input to a data line during a current horizontal period with a data signal input to the data line during a previous horizontal period.

2. The organic light emitting display device according to claim 1, wherein the reset signal and the reset voltage are supplied only when the data voltage applied to the data line during the previous period is greater than the data voltage applied to the data line during the current period.

3. The organic light emitting display device according to claim 1, wherein the demultiplexer controller comprises a comparator configured to compare data input to the data line during the current and previous horizontal periods, and a memory for storing data input during at least one horizontal period.

4. The organic light emitting display device according to claim 1, wherein the reset voltage is lower than the voltage of the data signal.

5. The organic light emitting display device according to claim 1, wherein the reset signal is supplied before the plurality of control signals are supplied.

6. The organic light emitting display device according to claim 1, wherein each of the pixels comprises:

an organic light emitting diode;

a storage capacitor for storing a voltage corresponding to the data signal;

a first transistor for supplying current corresponding to the voltage stored by the storage capacitor to the organic light emitting diode;

a second transistor coupled to the data line, a current scan line and a second electrode of the first transistor, the second transistor being turned on when a scan signal is supplied to the current scan line;

a third transistor coupled between a first electrode of the first transistor and a gate electrode of the first transistor, the third transistor being turned on when a scan signal is supplied to the current scan line; and

a sixth transistor coupled between the gate electrode of the first transistor and the data line, the sixth transistor being turned on when a scan signal is supplied to the previous scan line.

7. The organic light emitting display device according to claim 6, further comprising:

a fourth transistor coupled between the gate electrode of the first transistor and the storage capacitor; and

a fifth transistor coupled between the second electrode of the first transistor and the organic light emitting diode.

8. The organic light emitting display device according to claim 7, wherein the fourth and fifth transistors are turned on when an emission control signal is supplied from the scan driver, and turned off otherwise.

9. A method of driving an organic light emitting display device, the method comprising:

applying a reset voltage through each of a plurality of output lines during a horizontal period to supply a reset voltage to a plurality of data lines corresponding to each output line;

initializing a plurality of parasitic capacitors on the data lines with the reset voltage;

sequentially applying a plurality of data signals through each of the output lines to the plurality of corresponding data lines during the horizontal period after initializing the parasitic capacitors;

storing voltages corresponding to the data signals in respective pixels coupled to the plurality of data lines during a period when a scan signal is supplied to a current scan line; and

allowing the pixels to emit light corresponding to the charged voltages,

wherein the reset voltage is selectively supplied to the data lines based at least in part on a comparison of a data signal input to a data line during a current horizontal period with a data signal input to the data line during a previous horizontal period.

10. The driving method according to claim 9, wherein the reset voltage is supplied if the data voltage of the data line during the previous horizontal period is greater than the data voltage applied to the data line during the current horizontal period.

11. The driving method according to claim 9, wherein the voltage of the reset voltage is lower than the voltage of the data signal.

12. An organic light emitting display, comprising a data driver configured to supply a plurality of data signals and a reset voltage to each of a plurality of data lines during a horizontal period, wherein the reset signal is selectively supplied to the data lines based at least in part on a comparison of a data signal input to a data line during a current horizontal period with a data signal input to the data line during a previous horizontal period.

13. The organic light emitting display device according to claim 12, further comprising a plurality of demultiplexers, wherein the data signals and the reset voltage are supplied to the data lines through the demultiplexers.

14. The organic light emitting display device according to claim 12, wherein the reset voltage is supplied only when the data voltage applied to the data line during the previous period is greater than the data voltage applied to the data line during the current period.

15. The organic light emitting display device according to claim 12, further comprising a comparator configured to compare data input to the data line during the current and previous horizontal periods, and a memory for storing data input during at least one horizontal period.

16. The organic light emitting display device according to claim 12, wherein the voltage of the reset voltage is lower than the voltage of the data signal.

17. The organic light emitting display device according to claim 12 wherein the reset voltage is supplied before the plurality of data signals are supplied within a horizontal period.

18. The organic light emitting display device according to claim 12, wherein each of the pixels comprises:

an organic light emitting diode;

a storage capacitor for storing a voltage corresponding to the data signal;

a first transistor for supplying current corresponding to the voltage stored by the storage capacitor to the organic light emitting diode;

a second transistor coupled to the data line, a current scan line and a second electrode of the first transistor, the second transistor being turned on when a scan signal is supplied to the current scan line;

a third transistor coupled between a first electrode of the first transistor and a gate electrode of the first transistor, the third transistor being turned on when a scan signal is supplied to the current scan line; and

a sixth transistor coupled between the gate electrode of the first transistor and the data line, the sixth transistor being turned on when a scan signal is supplied to the previous scan line.

19. The organic light emitting display device according to claim 18, further comprising:

a fourth transistor coupled between the gate electrode of the first transistor and the storage capacitor; and

a fifth transistor coupled between the second electrode of the first transistor and the organic light emitting diode.

20. The organic light emitting display device according to claim 19, wherein the fourth and fifth transistors are turned on when an emission control signal is supplied from the scan driver, and turned off otherwise.