Display device and gamma setting method for the same

1. A display device receiving a video signal including grayscale data, and displaying images according to the input video signal, comprising:

a photosensor measuring illuminance of external light;

a timing controller connected to the photosensor, and receiving and processing a data signal according to a target gamma value corresponding to the measured illuminance among a plurality of gamma values for a reference curved line representing a relationship of a lightness variation according to a change of grayscale data to be applied to the measured illuminance environment, and outputting a processed data signal, the reference curved line being a relationship curved line between

(ΔL*/ΔGray)/(L*_max−L*_min) and ΔGray,

where

ΔL* is the change of lightness, ΔGray is the change of the grayscale, L*_max is a maximum value of the lightness that can be displayed, and L*_min is a minimum value of the lightness that can be displayed;

a data driver connected to the timing controller for receiving and applying the processed data signal to a plurality of pixels; and

a scan driver applying a scan signal to the plurality of pixels for the data signal to be applied to the plurality of pixels,

the timing controller constituting and storing the gamma values satisfying the reference curved line for the illuminance of the external light measured by the photosensor, as a table, and selecting a set gamma value in the table.

2. The display device of claim 1 , the reference curved line being set by a relationship between the change of the grayscale data and a value of which the lightness variation according to the change of the grayscale data is divided by an entire range of the lightness that can be displayed by the display device.

3. The display device of claim 1 , the target gamma value being a gamma value with reference to a dark room.

4. The display device of claim 1 , the target gamma value being 2.2.

5. A method setting a gamma value for a display device, comprising the steps of:

storing a plurality of gamma values satisfying a reference curved line with respect to illuminance of an external light as a table;

setting a target gamma value;

setting a reference curved line of a variation of a lightness according to a change of a grayscale for a range of the lightness that can be displayed for the grayscale of the display device by applying the target gamma value, the reference curved line being a relationship curved line between (ΔL*/ΔGray)/(L*_max−L*_min) and ΔGray,

where

ΔL* is the change of lightness, ΔGray is the change of the grayscale, L*_max is a maximum value of the lightness that can be displayed, and L*_min is a minimum value of the lightness that can be displayed;

selecting a set gamma value in the table; and

setting the set gamma value satisfying the reference curved line for the illuminance of the external light.

6. The method of claim 5 , the setting of the set gamma value satisfying the reference curved line being executed for a variation curved line of the lightness according to the change of the grayscale for a range of the lightness that can be displayed for the illuminance of the external light to be similar to the reference curved line.

7. The method of claim 5 , the setting of the set gamma value satisfying the reference curved line being executed for the set gamma value to be less than the target gamma value as the illuminance of the external light is increased.

8. The method of claim 5 , the target gamma value being the set gamma value with reference to a dark room.

9. The method of claim 5 , the target gamma value being 2.2.