Organic light emitting display device

• US 8,519,914 B2
• Filed: 08/26/2010
• Issued: 08/27/2013
• Est. Priority Date: 11/10/2009
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Kim, Yang-Wan
• Primary Examiner(s): Chang, Kent
• Assistant Examiner(s): AU, SCOTT D
• Application Number:
  US12/869,679
• Publication Number:
  US 20110109660A1
• Time in Patent Office: 1,097 Days
• Field of Search: 345 76- 90, 345/211, 345/214, 345/690
• US Class Current: 345/76
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• 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 2320/0295 by monitoring each display pixel
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• 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

An organic light emitting display device includes: pixels at crossing regions of scan lines, light emission control lines, sensing lines, and data lines; a sensor configured to extract deterioration information from organic light emitting diodes included in the pixels during a first sensing period and to extract threshold voltage and mobility information of driving transistors included in the pixels during a second sensing period; a converter configured to generate corrected data by changing input data based on the deterioration information and the threshold voltage and mobility information; and a data driver configured to supply data signals, the data signals being based on the corrected data during a driving period and being reference data signals during the second sensing period, wherein the sensor is configured to extract the threshold voltage and mobility information of the driving transistors using second electric currents from the pixels in response to the reference data signals.

Claims

1. An organic light emitting display device, comprising:

pixels at crossing regions of scan lines, light emission control lines, sensing lines, and data lines;

a sensor configured to extract deterioration information from organic light emitting diodes included in the pixels during a first sensing period and configured to extract threshold voltage and mobility information of driving transistors included in the pixels during a second sensing period;

a converter configured to generate corrected data by changing input data based on the deterioration information and the threshold voltage and mobility information extracted by the sensor;

a data driver configured to supply data signals to the data lines, the data signals being based on the corrected data during a driving period in which an image is displayed by the pixels and the data signals being reference data signals during the second sensing period; and

a switching unit coupled to the data lines for selectively connecting the data lines with the data driver or the sensor, the switching unit comprising a sensing circuit configured to extract the deterioration information and the threshold voltage and mobility information,

wherein the sensor is configured to extract, during the second sensing period, the threshold voltage and mobility information of the driving transistors utilizing second electric currents that are supplied from the pixels in response to the reference data signals, and

wherein the sensing circuit comprises;

an electric current source coupled to a data line of the data lines and configured to supply a first electric current the data line during the first sensing period;

a third switching element coupled between the electric current source and the switching unit;

a sensing resistor configured to be supplied with a second electric current of the second electric currents from a corresponding one of the pixels; and

a fourth switching element coupled between the sensing resistor and the switching unit.

2. The organic light emitting display device as claimed in claim 1, wherein each of the reference data signals corresponds to a gray level at which a maximum electric current is configured to flow in a corresponding one of the pixels.

3. The organic light emitting display device as claimed in claim 2, wherein each of the reference data signals corresponds to a white gray level.

4. The organic light emitting display device as claimed in claim 1, wherein the switching unit further comprises:

a first switching element coupled between a data line of the data lines and the data driver, configured to be kept turned-on during the driving period and configured to be repeatedly turned on and off during the second sensing period; and

a second switching element coupled between the data line and the sensor, configured to be kept tuned-on during the first sensing period, and configured to be alternately turned on and off with the first switching element during the second sensing period.

5. The organic light emitting display device as claimed in claim 4, further comprising:

a scan driver configured to sequentially supply scan signals to the scan lines while sequentially supplying light emission control signals to the light emission control lines during the driving period and the second sensing period; and

a sensing driver configured to sequentially supply sensing signals to the sensing lines during the first sensing period and the second sensing period.

6. The organic light emitting display device as claimed in claim 5, wherein the scan driver is configured to supply a scan signal of the scan signals to an i-th scan line of the scan lines and a light emission control signal of the light emission control signals to an i-th light emission control line of the light emission control lines such that the scan signal completely overlaps in time with the emission control signal.

7. The organic light emitting display device as claimed in claim 5, wherein the scan driver is configured to supply a scan signal of the scan signals and a light emission control signal of the light emission control signals such that the scan signal and the light emission control signal overlap in time with a period in which the first switching element is turned on during the second sensing period.

8. The organic light emitting display device as claimed in claim 5, wherein the sensing driver is configured to supply a sensing signal of the sensing signals to overlap in time with a period in which the second switching element is turned on during the second sensing period.

9. The organic light emitting display device as claimed in claim 1, wherein the sensor further includes:

an analog-to-digital converter configured to convert the deterioration information into a first digital value and the threshold voltage and mobility information into a second digital value.

10. The organic light emitting display device as claimed in claim 1, wherein the analog-to-digital converter is configured to convert a first voltage that appears across a corresponding one of the organic light emitting diodes when the first electric current is supplied into the first digital value, and converts a second voltage that appears across the sensing resistor, in response to the second electric current, into the second digital value.

11. The organic light emitting display device as claimed in claim 1, wherein the third switching element is configured to be kept turned-on during the first sensing period.

12. The organic light emitting display device as claimed in claim 1, wherein the fourth switching element is configured to be kept turned-on during the second sensing period.

13. The organic light emitting display device as claimed in claim 1, wherein the converter includes:

a memory configured to store the deterioration information and the threshold voltage and mobility information; and

a conversion circuit configured to generate the corrected data using the deterioration information and the threshold voltage and mobility information stored in the memory.

14. An organic light emitting display device, comprising:

pixels at crossing regions of scan lines, light emission control lines, sensing lines, and data lines;

a sensor configured to extract deterioration information from organic light emitting diodes included in the pixels during a first sensing period and configured to extract threshold voltage and mobility information of driving transistors included in the pixels during a second sensing period;

a converter configured to generate corrected data by changing input data based on the deterioration information and the threshold voltage and mobility information extracted by the sensor; and

a data driver configured to supply data signals to the data lines, the data signals being based on the corrected data during a driving period in which an image is displayed by the pixels and the data signals being reference data signals during the second sensing period,

wherein the sensor is configured to extract, during the second sensing period, the threshold voltage and mobility information of the driving transistors utilizing second electric currents that are supplied from the pixels in response to the reference data signals, and

wherein each of the pixels located in an i-th horizontal line comprises;

an organic light emitting diode of the organic light emitting diodes having a cathode electrode coupled to a second power source;

a first transistor coupled between a data line of the data lines and a first node and having a gate electrode coupled to an i-th scan line of the scan lines;

a third transistor coupled between a reference power source and a second node and having a gate electrode coupled to the i-th scan line;

a storage capacitor coupled between the first node and the second node;

a driving transistor of the driving transistors coupled between a first power source and an anode electrode of the organic light emitting diode, and having a gate electrode coupled to the second node;

a fourth transistor coupled between the first power source and the first node and having a gate electrode coupled to an i-th light emission control line of the emission control lines; and

a fifth transistor coupled between the anode electrode of the organic light emitting diode and the data line and having a gate electrode connected to an i-th sensing line of the sensing lines.

15. The organic light emitting display device as claimed in claim 14, wherein each of the pixels is configured to charge a voltage in the storage capacitor substantially independently of a voltage drop of a first power supplied from the first power source.

16. The organic light emitting display device as claimed in claim 14, wherein the data driver is configured to supply a data signal of the data signals having a voltage that is equal to or higher than that of the reference power source and lower than that of the first power source.

17. The organic light emitting display device as claimed in claim 14, further comprising a sixth transistor coupled between the driving transistor and the anode electrode of the organic light emitting diode and having a gate electrode coupled to the i-th light emission control line.

18. The organic light emitting display device as claimed in claim 14, wherein the second power source is configured to supply a high-level voltage during the second sensing period and low-level voltage during other periods.

19. An organic light emitting display device, comprising:

pixels at crossing regions of scan lines, light emission control lines, sensing lines, and data lines, each of the pixels comprising a driving circuit for providing a driving current substantially independent of a driving voltage supplied to a driving transistor of each of the pixels;

a sensor configured to extract deterioration information of organic light emitting diodes included in the pixels during a first sensing period and configured to extract threshold voltage and mobility information of driving transistors included in the pixels during a second sensing period;

a converter configured to generate corrected data by changing input data based on the deterioration information and the threshold voltage and mobility information extracted by the sensor;

a data driver configured to supply data signals to the data lines, the data signals being based on the corrected data during a driving period in which an image is displayed by the pixels and configured to supply reference data signals during the second sensing period; and

a switching unit coupled to the data lines for selectively connecting the data lines with the data driver or the sensor, the switching unit comprising a sensing circuit configured to extract the deterioration information and the threshold voltage and mobility information,

wherein, during the second sensing period, the sensor extracts the threshold voltage and mobility information of the driving transistor using second electric currents that are supplied from the pixels in response to the reference data signals, and

wherein the sensing circuit comprises;

an electric current source coupled to a data line of the data lines and configured to supply a first electric current the data line during the first sensing period;

a third switching element coupled between the electric current source and the switching unit;

a sensing resistor configured to be supplied with a second electric current of the second electric currents from a corresponding one of the pixels; and

a fourth switching element coupled between the sensing resistor and the switching unit.

20. An organic light emitting display device, comprising:

pixels at crossing regions of scan lines, light emission control lines, sensing lines, and data lines, each of the pixels comprising a driving circuit for providing a driving current substantially independent of a driving voltage supplied to a driving transistor of each of the pixels;

a sensor configured to extract deterioration information of organic light emitting diodes included in the pixels during a first sensing period and configured to extract threshold voltage and mobility information of driving transistors included in the pixels during a second sensing period;

a converter configured to generate corrected data by changing input data based on the deterioration information and the threshold voltage and mobility information extracted by the sensor; and

a data driver configured to supply data signals to the data lines, the data signals being based on the corrected data during a driving period in which an image is displayed by the pixels and configured to supply reference data signals during the second sensing period,

wherein, during the second sensing period, the sensor extracts the threshold voltage and mobility information of the driving transistor using second electric currents that are supplied from the pixels in response to the reference data signals,

wherein the driving circuit comprises;

a first transistor coupled between a data line of the data lines and a first node and having a gate electrode coupled to a scan line of the scan lines;

a third transistor coupled between a first power source for supplying a reference power source and a second node and having a gate electrode coupled to the scan line;

a storage capacitor coupled between the first node and the second node;

a fourth transistor coupled between the first node and a second power source for supplying the driving voltage; and

a second transistor coupled between the first power source and an anode electrode of an organic light emitting diode of the organic light emitting diodes.