PIXEL ARRAY AND ORGANIC LIGHT EMITTING DISPLAY DEVICE INCLUDING THE SAME

• US 20140152705A1
• Filed: 06/07/2013
• Published: 06/05/2014
• Est. Priority Date: 11/30/2012
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Kwon, Oh-Jo, Lee, Joo-Hyung, Choi, Won-Tae
• Granted Patent: US 9,443,473 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2310/0262 The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes
• 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 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: G09G 3/3275 Details of drivers for data electrodes

Abstract

A pixel array and an organic light emitting display device including the same, can display an image with uniform luminance by compensating for a variation in threshold voltage/mobility of a driving transistor for each pixel and compensating for a change in efficiency due to degradation of an organic light emitting diode. A first pixel among the pixel array includes an organic light emitting diode; a pixel circuit positioned among an anode electrode of the organic light emitting diode, a first scan line and a first data line through which a data signal is supplied to the first pixel, and controlling current flowing in the organic light emitting diode; and a switching element controlling the coupling between a second data line through which a data signal is supplied to a second pixel of the plurality of pixels and the anode electrode of the organic light emitting diode.

Claims

1. A pixel array, comprising:

a plurality of pixels,

with a first pixel among the plurality of pixels comprising;

an organic light emitting diode;

a pixel circuit positioned among an anode electrode of the organic light emitting diode, a first scan line and a first data line through which a first data signal is supplied to the first pixel, the pixel circuit controlling current flowing in the organic light emitting diode; and

a switching element controlling the coupling between a second data line through which a second data signal is supplied to a second pixel of the plurality of pixels and the anode electrode of the organic light emitting diode, in response to a control signal supplied through a control line.

2. The pixel array of claim 1, wherein the pixel circuit includes:

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

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

a storage capacitor coupled between the first power source and the first node.

3. The pixel array of claim 2, wherein the pixel circuit further includes a third transistor coupled between the first node and the anode electrode of the organic light emitting diode, having a gate electrode coupled to a second scan line.

4. An organic light emitting display device, comprising:

a pixel array having a plurality of pixels arranged at intersection portions of scan lines, data lines and control lines;

a scan driver supplying scan signals to the scan lines;

a data driver supplying data signals to the data lines; and

a control line driver supplying control signals to the control lines, with a first pixel among the plurality of pixels comprising;

an organic light emitting diode;

a pixel circuit positioned among an anode electrode of the organic light emitting diode, a corresponding first scan line of the scan lines and a first data line of the data lines, through which a first data signal is supplied to the first pixel, the pixel circuit controlling current flowing in the organic light emitting diode; and

a switching element controlling the coupling between a second data line through which a second data signal is supplied to a second pixel of the plurality of pixels and the anode electrode of the organic light emitting diode, in response to a control signal supplied through a corresponding control line of the control lines.

5. The organic light emitting display device of claim 4, wherein the pixel circuit includes:

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

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

a storage capacitor coupled between the first power source and the first node.

6. The organic light emitting display device of claim 5, wherein the pixel circuit further includes a third transistor coupled between the first node and the anode electrode of the organic light emitting diode, having a gate electrode coupled to a second scan line.

7. The organic light emitting display device of claim 4, further comprising:

a sensing unit sensing degradation information of the organic light emitting diode or threshold voltage/mobility of a driving transistor included in the first pixel, using the second data line; and

a switching unit selectively coupling the data lines to the sensing unit.

8. The organic light emitting display device of claim 7, wherein the sensing unit includes:

a current sink unit receiving current supplied from the first pixel through the second data line;

a current source unit supplying current to the first pixel through the second data line;

an analog-digital conversion unit converting a first voltage supplied through the current sink unit into a first digital value, and converting a second voltage supplied through the current source unit into a second digital value;

a first switch coupling the current sink unit to the switching unit while the threshold voltage/mobility information of the driving transistor is sensed; and

a second switch coupling the current source unit to the switching unit while the degradation information of the organic light emitting diode is sensed.

9. The organic light emitting display device of claim 7, wherein the switching unit includes:

a third switch coupling the first data line to the sensing unit; and

a fourth switch coupling the second data line to the sensing unit.

10. The organic light emitting display device of claim 9, wherein the first and second switches are turned off during a display period,

wherein the third switch is turned off and the fourth switch is turned on while the degradation information of the organic light emitting diode included in the first pixel, and

wherein the third and fourth switches are turned on while the threshold voltage/mobility information of the driving transistor included in the first pixel.

11. The organic light emitting display device of claim 7, further comprising:

a control block storing degradation information of the organic light emitting diode or threshold voltage/mobility of the driving transistor output from the sensing unit; and

a timing controller controlling the scan driver, the data driver and the control line driver, converting bits of data supplied, based on the degradation information or threshold voltage/mobility information stored in the control block, and outputting the converted data to the data driver.

12. The organic light emitting display device of claim 11, wherein the control block includes:

a memory storing degradation information of the organic light emitting diode or threshold voltage/mobility information of the driving transistor; and

a controller providing the timing controller with the degradation information of the organic light emitting diode or threshold voltage/mobility information of the driving transistor.