Display apparatus and driving method for the same

1. A display apparatus comprising:

a pixel array including a plurality of pixels of light-emitting elements constituting a screen, the pixel array being configured to display each frame of an image on the screen by emitting light having a luminance in accordance with the level of an image signal and to continuously emit light from the screen within each frame for an amount of time specified by a duty ratio;

a life control unit configured to extend the life of the light-emitting elements by simultaneously adjusting the maximum permissible level of the image signal and the duty ratio, the life control unit including an average luminance calculating circuit and a duty ratio and maximum permissible luminance level calculating circuit;

a signal output unit for driving the screen to display an image by outputting an image signal adjusted within the maximum permissible level to the pixel array;

a duty ratio transmission unit for enabling the screen to emit light for an amount of time specified by transmitting an adjusted duty ratio to the pixel array; and

a first gate driver for driving a duty signal to the pixels in the pixel array; and

a second gate driver for driving a write-in signal to the pixels in the pixel array;

wherein the life control unit detects the average luminance of the image from the input image signal, and

wherein the duty ratio specifying the light emission time per frame and the maximum permissible level of the image signal are reduced in inverse proportion to changes in the detected average luminance.

2. The display apparatus according to claim 1 , wherein the life control unit automatically adjusts the maximum permissible level and duty ratio in accordance with the input image in real time.

3. The display apparatus of claim 1 , wherein the maximum permissible level of luminance for the image signal traverses the range of 70 to 100 percent between the luminance levels of 200 to 600 nits, and the duty ratio traverses the range of 50 to 75 percent between the luminance levels of 200 to 600 nits.

4. The display apparatus of claim 1 , wherein the average luminance calculating circuit detects the average luminance of the image from the input image signal and provides average luminance data to the duty ratio and maximum permissible luminance level calculating circuit, and the duty ratio and maximum permissible luminance level calculating circuit generates a duty signal and a maximum output level signal based on the input calculated average luminance.

5. The display apparatus of claim 1 , wherein the second gate driver drives the write-in of data into the pixels in the pixel array in advance of the duty driving.

6. The display apparatus of claim 1 , wherein each pixel in the pixel array includes a switching TFT connected to and driven by an output signal from the first gate driver.

7. The display apparatus of claim 1 , wherein each pixel in the pixel array includes

a switching TFT connected to and driven by a duty signal from the first gate driver; and

a sampling TFT connected to and driven by a write signal from the second gate driver.

8. The display apparatus of claim 7 , wherein

each pixel is connected to a data signal, the duty signal, and the write signal, and the data signal is connected to the drain of the sampling TFT, the write signal is connected to the gate of the sampling TFT, and the duty signal is connected to the gate of the switching TFT.

9. A method for driving a display apparatus, the display apparatus having a screen comprised of a plurality of pixels of light-emitting elements, the method comprising the steps of:

displaying each frame of an adjusted image signal on the screen by emitting light from the plurality of light-emitting elements, the emitted light for each frame corresponding to a luminance level indicated by the adjusted image signal for an amount of time specified by a duty ratio;

extending the life of a plurality of pixels of light-emitting elements on said display by

detecting the average luminance of an image from an input image signal at an average luminance calculating circuit within a life control unit,

simultaneously adjusting a maximum permissible level of luminance of said input image signal to produce the adjusted image signal and adjusting the duty ratio based on said input image signal at a duty ratio and maximum permissible luminance level calculating circuit within the life control unit; and

outputting said adjusted image signal from the life control unit, said adjusted image signal including the adjusted maximum permissible level of luminance for the plurality of pixels and an adjusted duty ratio for the plurality of pixels;

driving a duty signal to the pixels in the pixel array using a first gate driver; and

driving a write-in signal to the pixels in the pixel array using a second gate driver;

wherein adjusting a maximum permissible level of luminance and adjusting the duty ratio includes

adjusting the duty ratio specifying the light emission time per frame and the maximum permissible level of the input image signal in inverse proportion to changes in the detected average luminance.

10. The method for driving a display apparatus of claim 9 , wherein the maximum permissible level of luminance for the image signal traverses the range of 70 to 100 percent between the luminance levels of 200 to 600 nits, and the duty ratio traverses the range of 50 to 75 percent between the luminance levels of 200 to 600 nits.

11. The method for driving a display apparatus of claim 9 , wherein extending the life of a plurality of pixels of light-emitting elements further includes:

receiving the input image signal at the average luminance calculating circuit;

providing detected average luminance data to the duty ratio and maximum permissible luminance level calculating circuit;

and generating a duty signal and a maximum output level signal at the duty ratio and maximum permissible luminance level calculating circuit, at the duty ratio and maximum permissible luminance level calculating circuit.

12. A display apparatus comprising:

a pixel array including a screen, the screen comprised of a plurality of pixels of light-emitting elements, the pixel array configured to display each frame of an image on the screen by emitting light having a luminance in accordance with an adjusted image signal for an amount of time specified by an adjusted duty ratio;

a life control unit, including an average luminance calculating circuit and a duty ratio and luminance level calculating circuit, the life control unit being configured to extend the life of the light-emitting elements by adjusting a duty ratio and image signal based on a determined permissible luminance level to produce the adjusted image signal;

a signal output unit for driving the screen to display an image by outputting the adjusted image signal to the pixel array;

a duty ratio transmission unit for transmitting the adjusted duty ratio to the pixel array; and

a first gate driver for driving a duty signal to the pixels in the pixel array; and

a second gate driver for driving a write-in signal data into the pixels in the pixel array.

13. The display apparatus of claim 12 , wherein the second gate driver drives the write-in signal to the pixels in the pixel array in advance of the duty signal from the first gate driver.

14. The display apparatus of claim 12 , wherein each pixel in the pixel array includes a switching TFT connected to and driven by the duty signal from the first gate driver.

15. The display apparatus of claim 12 , wherein each pixel in the pixel array includes

a switching TFT connected to and driven by the duty signal from the first gate driver; and

a sampling TFT connected to and driven by the write-in signal from the second gate driver.

16. The display apparatus of claim 15 , wherein

each pixel is connected to a data signal, the duty signal, and the write signal, and

the data signal is connected to the drain of the sampling TFT, the write-in signal is connected to the gate of the sampling TFT, and the duty signal is connected to the gate of the switching TFT.