DISPLAY DEVICE AND LUMINANCE CONTROL METHOD THEREFORE

• US 20150170560A1
• Filed: 08/11/2014
• Published: 06/18/2015
• Est. Priority Date: 12/17/2013
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: LIM, Kyongho
• Granted Patent: US 9,607,552 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2330/025 Reduction of instantaneous peaks of current
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• 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

A display device and a luminance control method therefore are provided. The display device comprises a luminance controller that establishes multiple peak luminance control (PLC) points by equally dividing a PLC curve and limits the luminance at the PLC point corresponding to the highest average pixel level (APL) at the initial luminance as the PLC curve slopes downward.

Claims

1. A display device which controls the luminance of pixels based on a peak luminance control (PLC) curve that defines the maximum luminance of pixels according to the average pixel level (APL) of an input image, the display device comprising:

a luminance controller that establishes multiple PLC points by equally dividing a PLC curve and limits the luminance at the PLC points with the highest APL at an initial luminance as the PLC curve slopes downward.

2. The display device of claim 1, wherein the luminance controller controls the luminance at the PLC points according to the following Equation:

P′

O=PO×

k

If Pi>

P′

O then P′

i=P′

O

others P′

i =Pi

where i=0, 1, 2, 3, 4, 5, 6, and 7, and k=1.00˜

0,

wherein P0 is the initial peak luminance, P′

0 is adjusted peak luminance, Pi is the initial luminance at the i-th PLC point which is lower than the peak luminance, and P′

i is the adjusted luminance at the i-th PLC point.

3. The display device of claim 2, wherein, when the PLC curve slopes downward according to user data, the luminance controller limits the luminance in an APL section extending from peak luminance to a critical PLC point at P0×

k and gradually decreases the luminance in an APL section after the critical PLC point,

wherein the critical PLC point is the PLC point with the lowest APL in the APL section where Pi<

P′

0 is satisfied.

4. The display device of claim 3, wherein two or more PLC points exist in the APL section extending from peak luminance to the critical PLC point.

5. The display device of claim 4, comprising:

a data driver that converts pixel data into a gamma compensation voltage to generate a data voltage, and outputs the data voltage to data lines;

a scan driver that supplies scan pulses synchronized with the data voltage to scan lines; and

a timing controller that transmits the pixel data to the data driver and controls the operation timings of the data driver and scan driver,

wherein the timing controller modulates the gray level of the pixel data based on the PLC curve or adjusts an high-potential pixel power voltage of the pixels or the gamma compensation voltage based on the PLC curve.

6. The display device of claim 5, wherein the display device is an OLED display or a plasma display panel.

7. A luminance control method for a display device, the method comprising:

forming a peak luminance control (PLC) curve that defines a maximum luminance of pixels according to an average pixel level (APL) of an input image;

establishing multiple PLC points by equally dividing the PLC curve; and

limiting the luminance at the PLC points corresponding to the highest APL at an initial luminance as the PLC curve slopes downward.

8. The method of claim 7, wherein, in the maintaining of the luminance at the PLC points with the highest APL at the initial luminance, the luminance at the PLC points is controlled according to the following Equation:

P′

O=PO×

k

If Pi≧

P′

O then P′

i=P′

O

others P′

i=Pi

where i=0, 1, 2, 3, 4, 5, 6, and 7, and k=1.00˜

0,

wherein PO is the initial peak luminance, P′

0 is adjusted peak luminance, Pi is the initial luminance at the i-th PLC point which is lower than the peak luminance, and P′

i is the adjusted luminance at the i-th PLC point.

9. The method of claim 8, comprising:

supplying a high-potential pixel power voltage to the pixels;

converting pixel data into a gamma compensation voltage to generate a data voltage, and outputting the data voltage to data lines;

modulating the gray level of the pixel data based on the PLC curve or adjusting the high-potential pixel power voltage or the gamma compensation voltage based on the PLC curve.