Organic light emitting display and driving method of operating the same

Patent metadata

Field	Value
Publication number	US-9959810-B2
Application number	US-201514619915-A
Country	US
Kind code	B2
Filing date	Feb 11, 2015
Priority date	Sep 19, 2014
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

An organic light emitting display, including a first data line extending along a first direction, a second data line extending along the first direction and disposed parallel to the first data line, a first scan line extending along a second direction perpendicular to the first direction, a first pixel connected to the first data line and the first scan line, a second pixel connected to the second data line and the first scan line, a first constant current source connected to the first data line, a second constant current source connected to the second data line, and a temperature information generation unit comprising a first input port connected to the first data line and a second input port connected to the second data line.

First claim

What is claimed is:

1. An organic light emitting display, comprising:
a first data line extending along a first direction;
a second data line extending along the first direction and disposed parallel to the first data line;
a first scan line extending along a second direction perpendicular to the first direction;
a first pixel connected to the first data line and the first scan line;
a second pixel connected to the second data line and the first scan line;
a first constant current source connected to the first data line and configured to generate a first driving current in a driving transistor of the first pixel;
a second constant current source connected to the second data line and configured to generate a second driving current in a driving transistor of the second pixel, the second driving current being different than the first driving current; and
a temperature circuit comprising a first input port connected to the first data line and a second input port connected to the second data line,
wherein the first driving current and the second driving current are driving currents corresponding to a sub-threshold region of the driving transistor,
wherein the sub-threshold region being a voltage range in which the driving current has an exponential relationship with a temperature of the driving transistor, and
wherein the temperature circuit is configured to generate:
a first temperature information by using the first driving current and the second driving current;
a second temperature information by using a third driving current and a fourth driving current, the third driving current is obtained by doubling the size of the first driving current, the fourth driving current is obtained by doubling the size of the second driving current; and
a final temperature information by using the first temperature information and the second temperature information.

2. The organic light emitting display of claim 1 , further comprising
a first gate line extending along the second direction and connected to the first pixel and the second pixel.

3. The organic light emitting display of claim 2 , wherein the first pixel comprises:
a control transistor configured to be turned on by a scan signal provided by the first scan line;
a sensing transistor configured to be turned on by a gate signal provided simultaneously with the scan signal through the first gate line;
an organic light emitting device configured to emit light in response to receiving the driving current from the driving transistor connected to a first end of the organic light emitting device; and
a switch configured to block a connection between the first end of the organic light emitting device and the driving transistor.

4. The organic light emitting display of claim 1 , wherein the temperature circuit is configured to:
calculate a voltage difference between a first voltage applied through the first input port and a second voltage applied through the second input port; and
convert the calculated voltage difference into a digital value.

5. The organic light emitting display of claim 4 , wherein:
the first voltage is a gate voltage of the driving transistor of the first pixel; and
the second voltage is a gate voltage of the driving transistor of the second pixel.

6. The organic light emitting display of claim 1 , wherein the temperature circuit generates the final temperature information by deducting the second temperature information from a third temperature information.

7. A method of driving an organic light emitting display comprising pixels arranged in a matrix form, scan lines and gate lines extending in a horizontal direction, and data lines extending in a vertical direction, the method comprising:
activating a temperature sensing mode of the pixels;
providing scan signals and gate signals simultaneously to the scan lines and the gate lines;
supplying a first constant current to an a th data line and a second constant current different in size from the first constant current to a b th data line;
calculating a voltage difference between a first voltage generated in the a th data line by the first constant current source and a second voltage generated in the b th data line by the second constant current source; and
calculating a temperature information,
wherein a is an odd-numbered constant and b is an even-numbered constant, and
wherein calculating of the temperature information comprises:
generating a first temperature information by using the first driving current and the second driving current;
generating a second temperature information by using a third driving current and a fourth driving current, the third driving current being obtained by doubling the size of the first driving current, and the fourth driving current being obtained by doubling the size of the second driving current; and
generating a final temperature information by using the first temperature information and the second temperature information,
wherein a driving transistor of a pixel connected to the ath data line generates the first driving current from the first constant current;
the driving transistor of the pixel connected to the bth data line generates the second driving current from the second constant current, the second driving current having different size with respect to the first driving current; and
the first driving current and the second driving current are driving currents corresponding to a sub-threshold region of the driving transistor, the sub-threshold region being a voltage range in which the driving current has an exponential relationship with a temperature of the driving transistor.

8. The method of claim 7 , wherein the activating the temperature sensing mode comprises:
connecting the first constant current source supplying the first constant current to the a th data line;
connecting the second constant current source supplying the second constant current to the b th data line; and
blocking a connection between an organic light emitting device and a driving transistor of the pixels.

9. The method of claim 7 , wherein the final temperature information is generated by deducting the second temperature information from a third temperature information.

10. The method of claim 7 , wherein calculating of the temperature information comprises converting the voltage difference between the first voltage and the second voltage in to a digital value.

Assignees

• Samsung Display Co Ltd

Inventors

• Kim Hyun Sik

Classifications

• G09G3/3275 Primary

  Details of drivers for data electrodes · CPC title

• G09G2320/041

  Temperature compensation · CPC title

• G09G2320/029

  by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel · CPC title

• G09G3/3233

  with pixel circuitry controlling the current through the light-emitting element · CPC title

• G09G2320/0295

  by monitoring each display pixel · CPC title