Organic light emitting diode display having function for controlling peak luminance using weighted average picture level and method for driving the same

Patent metadata

Field	Value
Publication number	US-9378682-B2
Application number	US-201314100711-A
Country	US
Kind code	B2
Filing date	Dec 9, 2013
Priority date	Apr 30, 2013
Publication date	Jun 28, 2016
Grant date	Jun 28, 2016

Abstract

Provided is an organic light emitting diode display including a display panel having data lines, gate lines, and pixels disposed in a matrix form in a crossing region of the data lines and the gate lines, a gamma reference voltage adjustment unit that calculates a weighted average picture level of digital video data, adjusts gamma reference voltages so that peak luminance of the display panel is reduced as the weighted average picture level is increased, and outputs the adjusted gamma reference voltages, a data driving circuit converting the digital video data into analog data voltages by using the gamma reference voltages, and supplying the data voltages to the data lines, and a gate driving circuit sequentially outputting gate pulses to the gate lines.

First claim

What is claimed is:

1. An organic light emitting diode display comprising:
a display panel including data lines, gate lines, and pixels disposed in a matrix form in a crossing region of the data lines and the gate lines;
a gamma reference voltage adjustment unit calculating a weighted average picture level of digital video data, adjusting gamma reference voltages so that peak luminance of the display panel is reduced as the weighted average picture level is increased, and outputting the adjusted gamma reference voltages;
a data driving circuit converting the digital video data into analogue data voltages by using the gamma reference voltages, and supplying the data voltages to the data lines; and
a gate driving circuit sequentially outputting gate pulses to the gate lines,
wherein the gamma reference voltage adjustment unit includes:
a grayscale representative value calculator calculating a maximum value of red, green, and blue data of pixel data as a grayscale representative value of the pixel data; and
a weighted average picture level calculator calculating a sum of values obtained by dividing a square of the grayscale representative value by a peak white grayscale as a first value, calculating a sum of values obtained by dividing the grayscale representative value by the peak white grayscale as a second value, and calculating a value obtained by dividing the first value by the second value as the weighted average picture level.

2. The organic light emitting diode display of claim 1 , wherein the gamma reference voltage adjustment unit further includes:
a gamma reference voltage adjustment data output unit including a look-up table storing gamma reference voltage adjustment data including high potential voltage data and tap voltage data, and outputting the gamma reference voltage adjustment data stored in the look-up table according to the weighted average picture level; and
a gamma reference voltage output circuit differently outputting the gamma reference voltages according to the gamma reference voltage adjustment data by adjusting a high potential voltage and tap voltages according to the gamma reference voltage adjustment data.

3. The organic light emitting diode display of claim 2 , wherein the gamma reference voltage adjustment data are data adjusting the gamma reference voltages so that the gamma reference voltages are reduced as the weighted average picture level is increased.

4. The organic light emitting diode display of claim 3 , wherein the gamma reference voltage output circuit includes:
a digital analogue converter converting the high potential voltage data and the tap voltage data of the gamma reference voltage adjustment data into the high potential voltage and the tap voltages and outputting the high potential voltage and the tap voltages; and
a voltage divider circuit dividing the high potential voltage, the tap voltages, and a low potential voltage and outputting the gamma reference voltages.

5. The organic light emitting diode display of claim 1 , wherein the data driving circuit includes the voltage divider circuit dividing the gamma reference voltages and outputting gamma compensation voltages, and converts the digital video data into the data voltages by using the gamma compensation voltages.

6. A method for driving an organic light emitting diode display including a display panel having data lines, gate lines, and pixels disposed in a matrix form in a crossing region of the data lines and the gate lines, comprising:
calculating a weighted average picture level of digital video data, adjusting gamma reference voltages so that peak luminance of the display panel is reduced as the weighted average picture level is increased, and outputting the gamma reference voltages;
converting the digital video data into analogue data voltages by using the gamma reference voltages, and supplying the data voltages to the data lines; and
sequentially outputting gate pulses to the gate lines,
wherein the calculating of the weighted average picture level of the digital video data, the adjusting of the gamma reference voltages so that the peak luminance of the display panel is reduced as the weighted average picture level is increased, and the outputting of the gamma reference voltages includes:
calculating a maximum value of red, green, and blue data of pixel data as a grayscale representative value of the pixel data; and
calculating a sum of values obtained by dividing a square of the grayscale representative value by a peak white grayscale as a first value, calculating a sum of values obtained by dividing the grayscale representative value by the peak white grayscale as a second value, and calculating a value obtained by dividing the first value by the second value as the weighted average picture level.

7. The method of claim 6 , wherein the calculating of the weighted average picture level of the digital video data, the adjusting of the gamma reference voltages so that the peak luminance of the display panel is reduced as the weighted average picture level is increased, and the outputting of the gamma reference voltages further includes:
outputting gamma reference voltage adjustment data stored in a look-up table according to the weighted average picture level; and
differently outputting the gamma reference voltages according to the gamma reference voltage adjustment data by adjusting a high potential voltage and tap voltages according to the gamma reference voltage adjustment data.

8. The method of claim 7 , wherein the gamma reference voltage adjustment data are data adjusting the gamma reference voltages so that the gamma reference voltages are reduced as the weighted average picture level is increased.

9. The method of claim 7 , wherein the differently outputting of the gamma reference voltages according to the gamma reference voltage adjustment data includes:
converting high potential voltage data and tap voltage data of the gamma reference voltage adjustment data into the high potential voltage and the tap voltages, and outputting the high potential voltage and the tap voltages; and
dividing the high potential voltage, the tap voltages, and a low potential voltage, and outputting the gamma reference voltages.

10. The method of claim 6 , wherein in the converting of the digital video data into the analogue data voltages by using the gamma reference voltages, and the supplying of the data voltages to the data lines, the gamma reference voltages are divided by using a voltage divided circuit, gamma compensation voltages are outputted, and the digital video data are converted into the data voltages by using the gamma compensation voltages.

Assignees

• Lg Display Co Ltd

Inventors

• Lim Kyongho
• Park Sunhee

Classifications

• G09G2360/16

  Calculation or use of calculated indices related to luminance levels in display data · CPC title

• G09G2320/0673

  for control of gamma adjustment, e.g. selecting another gamma curve · CPC title

• G09G2330/021

  Power management, e.g. power saving · CPC title

• G09G3/3291 Primary

  in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements · CPC title

• H10K59/123 Primary

  Connection of the pixel electrodes to the thin film transistors [TFT] · CPC title