Organic light emitting display

• US 20080150847A1
• Filed: 04/26/2007
• Published: 06/26/2008
• Est. Priority Date: 12/21/2006
• 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: Kim, Hyung-Soo, Chung, Bo-Yong, Choi, Sang-Moo, Lee, Wang-Jo
• Granted Patent: US 8,040,303 B2
• Time in Patent Office: Days
• US Class Current: 345/82
• 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 2300/0852 being a dynamic memory with more than 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 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

An organic light emitting display, suitable for a high quality and high resolution display device, rapidly charges a data voltage using a voltage programming technique, after compensating for a deviations in the threshold voltage and mobility of a driving transistor using a current programming technique. The organic light emitting display includes: a data line supplying a data signal; a scan line supplying a scan signal; a first switching element, electrically coupling its control electrode to the scan line, transferring the data signal supplied from the data line; a driving transistor, electrically coupling its control electrode to the first switching element, controlling a driving current of a first voltage line; a first capacitive element electrically coupled between the first switching element and the control electrode of the driving transistor; an Organic Light Emitting Diode (OLED), electrically coupled between the driving transistor and a second power voltage line, displaying an image by a current supplied from the driving transistor; and a fourth switching element compensating for deviations of characteristics of the driving transistor by supplying a current of the first current line to the driving transistor.

Claims

1. An organic light emitting display, comprising:

a first switching element, having a control electrode thereof electrically coupled to a scan line, to transfer a data signal supplied by a data line;

a driving transistor, having a control electrode electrically coupled to the first switching element, to control a driving current of a first power supply voltage line;

a first capacitive element electrically coupled between the first switching element and the control electrode of the driving transistor;

an Organic Light Emitting Diode (OLED), electrically coupled between the driving transistor and a second power supply voltage line, to display an image in response to a current supplied by the driving transistor; and

a fourth switching element to supply a current of a first current line to the driving transistor, the current of the first current line compensating for deviations in characteristics of the driving transistor.

2. The organic light emitting display of claim 1, wherein the fourth switching element has a first electrode electrically coupled to the first current line, and a second electrode electrically coupled between the driving transistor and the OLED.

3. The organic light emitting display of claim 1, wherein deviations in characteristics of the driving transistor are compensated for by turning on the fourth switching element to supply a current from the first current line, and then turning on the first switching element to program a data voltage to the first capacitive element.

4. The organic light emitting display of claim 1, further comprising a second switching element to selectively connect the driving transistor in a diode configuration.

5. The organic light emitting display of claim 4, wherein the second switching element has a first electrode electrically coupled between the control electrode of the driving transistor and the first capacitive element, and a second electrode electrically coupled between the driving transistor and the fourth switching element.

6. The organic light emitting display of claim 1, further comprising a third switching element electrically coupled between the first power supply voltage line and the first capacitive element.

7. The organic light emitting display of claim 6, wherein the third switching element has a first electrode electrically coupled to the first voltage line, and a second electrode electrically coupled between the first switching element and the first capacitive element.

8. The organic light emitting display of claim 1, further comprising a fifth switching element to transmit a current supplied by the driving transistor to the OLED.

9. The organic light emitting display of claim 8, wherein the fifth switching element has a first electrode electrically coupled between the driving transistor and the fourth switching element, and a second electrode electrically coupled to the OLED.

10. The organic light emitting display of claim 1, further comprising:

a second switching element to selectively connect the driving transistor in a diode configuration;

a third switching element to supply a voltage of the first voltage line to the first capacitive element; and

a fifth switching element to transmit a current supplied by the driving transistor to the OLED.

11. The organic light emitting display of claim 10, wherein the second switching element has a first electrode electrically coupled between the control electrode of the driving transistor and the first capacitive element, and a second electrode electrically coupled between the driving transistor and the fourth switching element.

12. The organic light emitting display of claim 10, wherein the third switching element has a first electrode electrically coupled to the first voltage line, and a second electrode electrically coupled between the first switching element and the first capacitive element.

13. The organic light emitting display of claim 10, wherein the fifth switching element has a first electrode electrically coupled between the driving transistor and the fourth switching element, and a second electrode electrically coupled to the OLED.

14. The organic light emitting display of claim 10, wherein control electrodes of the second, third, and fourth switching elements are coupled to a direct scan line.

15. The organic light emitting display of claim 14, wherein the fifth switching element has a control electrode electrically coupled to a light emitting control line.

16. The organic light emitting display of claim 15, wherein the first, second, third, fourth, and fifth switching elements and the driving transistor each comprise a P-channel transistor.

17. The organic light emitting display of claim 15, wherein, for a compensation period in an image display period of one frame, the current from the first current line is supplied to the driving transistor to compensate for a threshold voltage of the driving transistor in response to the second and third and fourth switching elements being turned on and the first and fifth switching elements being turned off.

18. The organic light emitting display of claim 15, wherein, for a programming period in the image display period of one frame, a data voltage from the data line is supplied to the first electrode of the first capacitive element in response to the second, third, fourth, and fifth switching elements being turned off.

19. The organic light emitting display of claim 15, wherein for a light emitting period in the image display period of one frame, a voltage stored in the first capacitive element is supplied to the OLED to emit light in response to the fifth switching element being turned on, and the first, second, third, and fourth switching elements being turned off.

20. The organic light emitting display of claim 10, further comprising a second capacitive element having a first electrode electrically coupled between the first voltage line and the third switching element, and a second electrode electrically coupled between the first capacitive element and the control electrode of the driving transistor.

21. The organic light emitting display of claim 20, wherein control electrodes of the second, third, and fourth switching elements are coupled to the direct scan line, and a control electrode of the fifth switching element is coupled to the light emitting control line.

22. The organic light emitting display of claim 10, further comprising a second capacitive element having a first electrode electrically coupled between the first voltage line and the first electrode of the third switching element, and a second electrode electrically coupled between the first capacitive element and the second electrode of the third switching element.

23. The organic light emitting display of claim 22, wherein control electrodes of the second, third, and fourth switching elements are electrically coupled to the direct scan line, and the control electrode of the fifth switching is electrically coupled to the light emitting control line.