Display device, gamma correction circuit and display driving method

1. A display device comprising:

a substrate having a display area for displaying an image, the display area including:

a first driving area, a second driving area, and a boundary driving area between the first driving area and the second driving area; and

a plurality of pixels including a plurality of first pixels disposed in the first driving area, a plurality of second pixels disposed in the second driving area, a plurality of third pixels disposed in the boundary driving area, and a plurality of fourth pixels disposed in the boundary driving area,

wherein the number of pixels per unit area in the second driving area is less than the number of pixels per unit area in the first driving area,

wherein each of the plurality of first pixels has a first luminance for a first grayscale according to a first gamma curve, each of the plurality of second pixels has a second luminance for the first grayscale according to a second gamma curve, each of the plurality of third pixels has a third luminance for the first grayscale according to a third gamma curve, and each of the plurality of fourth pixels has a fourth luminance for the first grayscale according to the third gamma curve,

wherein all of the first gamma curve, the second gamma curve, and the third gamma curve are different from each other, and all of the first luminance, the second luminance, the third luminance, and the fourth luminance are different from each other,

wherein among the first luminance, the second luminance, the third luminance, and the fourth luminance, the second luminance is the highest, the third luminance is higher than the first luminance and lower than the second luminance, and the fourth luminance is lower than the first luminance, and

wherein among the plurality of third pixels and the plurality of fourth pixels disposed in the boundary driving area, each of the plurality of fourth pixels emits darker light than each of the plurality of third pixels.

2. The display device of claim 1 , wherein the second driving area comprises one or more transmissive areas allowing light to be transmitted.

3. The display device of claim 1 , wherein, during operation, luminance of the first driving area, luminance of the second driving area, and luminance of the boundary driving area are perceived as the same as each other.

4. The display device of claim 1 , wherein among the first luminance, the second luminance, and the third luminance, the second luminance is the highest, and the third luminance is higher than the first luminance and lower than the second luminance.

5. The display device of claim 1 , wherein the first gamma curve has a first slope at the first grayscale, the second gamma curve has a second slope at the first grayscale, and the third gamma curve has a third slope at the first grayscale, and

wherein among the first slope, the second slope, and the third slope, the second slope is greatest, and the third slope is greater than the first slope and less than the second slope.

6. A display device comprising:

a substrate having a display area for displaying an image the display area including:

a first driving area, a second driving area, and a boundary driving area between the first driving area and the second driving area; and

a plurality of pixels including a plurality of first pixels disposed in the first driving area, a plurality of second pixels disposed in the second driving area, a plurality of third pixels disposed in the boundary driving area, and a plurality of fourth pixels disposed in the boundary driving area,

wherein the number of pixels per unit area in the second driving area is less than the number of pixels per unit area in the first driving area,

wherein each of the plurality of first pixels has a first luminance for a first grayscale according to a first gamma curve, each of the plurality of second pixels has a second luminance for the first grayscale according to a second gamma curve, each of the plurality of third pixels has a third luminance for the first grayscale according to a third gamma curve, and each of the plurality of fourth pixels has a fourth luminance for the first grayscale according to the third gamma curve,

wherein all of the first gamma curve, the second gamma curve, and the third gamma curve are different from each other, and all of the first luminance, the second luminance, the third luminance, and the fourth luminance are different from each other,

wherein: image data to be supplied to each of the plurality of first pixels disposed in the first driving area is image data obtained by correcting first original image data according to the first gamma curve;

image data to be supplied to each of the plurality of second pixels disposed in the second driving area is image data obtained by correcting second original image data according to the second gamma curve;

image data to be supplied to each of the plurality of fourth pixels disposed in the boundary driving area is image data corrected according to the third gamma curve after fourth original image data is multiplied by a first gain; and

image data to be supplied to each of the plurality of third pixels disposed in the boundary driving area is image data corrected according to the third gamma curve after third original image data is multiplied by a second gain different from the first gain.

7. The display device of claim 1 , wherein the plurality of third pixels of the boundary driving area are arranged in a same layout at each location in the boundary driving area.

8. The display device of claim 1 , wherein the number of pixels per unit area in the boundary driving area is either equal to the number of pixels per unit area in the first driving area, or greater than the number of pixels per unit area in the second driving area and less than the number of pixels per unit area in the first driving area.

9. The display device of claim 1 , wherein the display area comprises an optical area allowing light to be transmitted and a normal area different from the optical area,

wherein the first driving area is included in the normal area, and the second driving area is included in the optical area, and

wherein the boundary driving area, which is an area between the first driving area and the second driving area, is included in the normal area or an optical bezel area between the normal area and the optical area,

further comprising: one or more optical electronic devices located under the substrate and overlapping the optical area,

wherein the one or more optical electronic devices performs a selected operation by receiving light transmitting through the optical area.

10. The display device of claim 1 , further comprising: a gamma correction circuit configured to correct image data based on a gamma curve corresponding to a location to which the image data is supplied among the first gamma curve, the second gamma curve, and the third gamma curve, and output the corrected image data.

11. A gamma correction circuit comprising:

an area recognizing circuit configured to recognize an area where a subpixel to which image data is to be supplied is disposed as one of a first driving area, a second driving area, and a boundary driving area between the first driving area and the second driving area;

a gamma curve selecting circuit configured to select a gamma curve corresponding to the recognized area among a first gamma curve for the first driving area, a second gamma curve for the second driving area, and a third gamma curve for the boundary driving area; and

a gamma correction processor for correcting the image data based on the selected gamma curve, and outputting the corrected image data,

wherein the first driving area includes a plurality of first pixels, the second driving area includes a plurality of second pixels, and the boundary driving area includes a plurality of third pixels and a plurality of fourth pixels,

wherein each of the plurality of first pixels has a first luminance for a first grayscale according to the first gamma curve, each of the plurality of second pixels has a second luminance for the first grayscale according to the second gamma curve, each of the plurality of third pixels has a third luminance for the first grayscale according to the third gamma curve, and each of the plurality of fourth pixels has a fourth luminance for the first grayscale according to the third gamma curve,

wherein among the first luminance, the second luminance, the third luminance, and the fourth luminance, the second luminance is the highest, the third luminance is higher than the first luminance and lower than the second luminance, and the fourth luminance is lower than the first luminance, and

wherein among the plurality of third pixels and the plurality of fourth pixels disposed in the boundary driving area, each of the plurality of fourth pixels emits darker light than each of the plurality of third pixels.

12. The gamma correction circuit of claim 11 , wherein the first gamma curve has a first slope at the first grayscale, the second gamma curve has a second slope at the first grayscale, and the third gamma curve has a third slope at the first grayscale, and

wherein among the first slope, the second slope, and the third slope, the second slope is greatest, and the third slope is greater than the first slope and less than the second slope.

13. A display driving method comprising:

recognizing an area where a subpixel to which image data is to be supplied is disposed as one of a first driving area, a second driving area, and a boundary driving area between the first driving area and the second driving area; and

among a first gamma for the first driving area, a second gamma for the second driving area, and a third gamma for the boundary driving area, correcting the image data based on a gamma corresponding to the recognized area, and outputting the corrected image date,

wherein the first driving area includes a plurality of first pixels, the second driving area includes a plurality of second pixels, and the boundary driving area includes a plurality of third pixels and a plurality of fourth pixels,

wherein each of the plurality of first pixels has a first luminance for a first grayscale according to a first gamma, each of the plurality of second pixels has a second luminance for the first grayscale according to a second gamma, each of the plurality of third pixels has a third luminance for the first grayscale according to a third gamma, and each of the plurality of fourth pixels has a fourth luminance for the first grayscale according to the third gamma,

wherein among the first luminance, the second luminance, the third luminance, and the fourth luminance, the second luminance is the highest, the third luminance is higher than the first luminance and lower than the second luminance, and the fourth luminance is lower than the first luminance, and

wherein among the plurality of third pixels and the plurality of fourth pixels disposed in the boundary driving area, each of the plurality of fourth pixels emits darker light than each of the plurality of third pixels.

14. The display driving method of claim 13 , wherein among a first luminance at a first grayscale according to the first gamma, a second luminance at the first grayscale according to the second gamma, and a third luminance at the first grayscale according to the third gamma, the second luminance is the highest, and the third luminance is higher than the first luminance and lower than the second luminance.