Digital gamma correction system and method

• US 20090231256A1
• Filed: 12/18/2008
• Published: 09/17/2009
• Est. Priority Date: 03/17/2008
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kim, Eui Tae
• Granted Patent: US 8,542,256 B2
• Time in Patent Office: Days
• US Class Current: 345/89
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2360/147 the originated light output being determined for each pixel
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A digital gamma correction system for detecting a brightness of a liquid crystal panel, and correcting a gamma voltage, based on the detected brightness, includes an offset setter for setting the number of detection gray levels and a first detection area, for the detection of the brightness of the liquid crystal panel, a plurality of brightness detectors for detecting brightness values output from the first detection area for the detection gray levels, a controller for processing the brightness values detected by the brightness detectors, a non-linear interpolation data processor for processing a brightness value supplied from the controller, thereby generating non-linear interpolation data as a brightness variation rate according to the gray levels, a brightness corrector for generating gamma correction data for brightness values obtained by interpolating brightness values detected in a second detection area of another liquid crystal panel for a second number of detection gray levels, based on the non-linear interpolation data, and a memory for storing the gamma correction data generated from the brightness corrector.

Claims

1. A digital gamma correction system for detecting a brightness of a liquid crystal panel, and correcting a gamma voltage, based on the detected brightness, comprising:

an offset setter for setting the number of detection gray levels and a first detection area, for the detection of the brightness of the liquid crystal panel;

a plurality of brightness detectors for detecting brightness values output from the first detection area according to the detection gray;

a controller for processing the brightness values detected by the brightness detectors;

a non-linear interpolation data processor for processing the brightness values supplied from the controller, thereby generating non-linear interpolation data as a brightness variation rate according to the gray levels;

a brightness corrector for generating gamma correction data for brightness values obtained by interpolating brightness values detected in a second detection area of another liquid crystal panel for a second number of detection gray levels, based on the non-linear interpolation data; and

a memory for storing the gamma correction data generated from the brightness corrector.

2. The digital gamma correction system according to claim 1, wherein the number of the second detection gray levels is smaller than the number of the first detection gray levels, to achieve a reduction in tact time.

3. The digital gamma correction system according to claim 1, wherein the non-linear interpolation data processor comprises:

a brightness interpolator for interpolating the brightness values detected in the first detection region at the detection gray levels;

a brightness variation rate calculator for calculating variation rates of the interpolated brightness values;

a normalization curve creator for creating normalizing curves, using the calculated interpolated brightness variation rates;

a normalizing curve average calculator for calculating an average of the normalizing curves; and

a non-linear interpolation data storing unit for storing the normalizing curve average.

4. A digital gamma correction method comprising:

A) measuring brightness values output from a first detection area in a first liquid crystal panel while varying gray levels, thereby generating a normalizing curve as a reference;

B) executing a non-linear interpolation for brightness values measured in another liquid crystal panel in accordance with variation rates of the measured brightness values, while referring to the normalizing curve, thereby generating gamma reference voltages; and

C) matching each gamma reference voltage of the another liquid crystal panel with an ideal gamma reference voltage, thereby generating gamma correction data.

5. The digital gamma correction method according to claim 4, wherein the step A comprises:

setting, in an offset setter, the number of first detection gray levels, at which a brightness of the first liquid crystal panel will be detected in a first detection region as a detection region of the first liquid crystal panel;

detecting brightness values by a plurality of brightness detectors for the number of the first detection gray levels;

interpolating the detected brightness values by a controller, to generate brightness values corresponding to gray levels suitable for the first liquid crystal panel;

calculating variation rates of the interpolated brightness values according to the variation of the gray levels;

normalizing the brightness variation rates according to the gray levels variation, thereby creating normalizing curves; and

calculating an average of the normalizing curves created in accordance with the brightness values detected by the brightness detectors, and storing the normalizing curve average in a non-linear interpolation data storing unit.

6. The digital gamma correction method according to claim 5, wherein the step B comprises:

setting, in the offset setter, the number of second detection gray levels, at which a brightness of the another liquid crystal panel will be detected in a second detection region as a detection region of the another liquid crystal panel;

executing a non-linear interpolation for the brightness values detected from the another liquid crystal panel, while referring to the brightness variation rate stored in the non-linear interpolation data storing unit for each gray level; and

generating gamma reference voltages, based on the non-linearly interpolated brightness values.

7. The digital gamma correction method according to claim 6, wherein the number of the second detection gray levels is smaller than the number of the first detection gray levels, to achieve a reduction in tact time.