Display device
Provided is a display device including a display panel, an optical sensor, a timing controller, a scan driver, a data driver, and an image controller. The timing controller controls an image refresh rate of the display panel based on a refresh rate control signal. Thus, the display device provides improved visibility.
1. A display device comprising:
a display panel including pixels;
an optical sensor configured to measure an optical waveform of the display panel;
a timing controller configured to generate image data based on input image data and generate a first control signal and a second control signal based on a control signal;
a scan driver configured to supply a scan signal to the pixels based on the first control signal;
a data driver configured to generate a data signal corresponding to the image data based on the second control signal and the image data to supply it to the pixels; and
an image controller configured to detect optical characteristic information of the display panel based on the optical waveform, determine a threshold value based on the optical waveform, an image refresh rate of the display panel, and grayscale values corresponding to the input image data, and generate a refresh rate control signal for controlling the image refresh rate based on the optical characteristic information and the threshold value,
wherein the timing controller controls the image refresh rate of the display panel based on the refresh rate control signal.
2. The display device of claim 1 , wherein the display panel is driven at a first refresh rate in a first period and is driven at the second refresh rate in a second period after the first period, and
wherein the first refresh rate is greater than the second refresh rate.
3. The display device of claim 2 , wherein the optical characteristic information includes a value of flashing luminance, and
wherein the value of the flashing luminance corresponds to a maximum value of perceived luminance perceived by a user corresponding to a time point at which the image refresh rate is changed from the first period to the second period.
4. The display device of claim 3 , wherein the image controller compares the value of the flashing luminance with the threshold value and generates the refresh rate control signal in response to the compared result.
5. The display device of claim 4 , wherein, when the value of the flashing luminance is equal to or greater than the threshold value, the image controller controls the image refresh rate of the display panel to be gradually changed from the first refresh rate in the first period to the second refresh rate in the second period.
6. The display device of claim 5 , wherein the image controller controls the display panel to be driven at a third refresh rate in a third period disposed between the first period and the second period, and
wherein the third refresh rate has a value between the first refresh rate and the second refresh rate.
7. The display device of claim 4 , wherein, when the value of the flashing luminance is less than the threshold value, the image controller controls the image refresh rate of the display panel to be immediately changed from the first refresh rate in the first period to the second refresh rate in the second period.
8. The display device of claim 3 , wherein the image controller includes:
a refresh rate calculator configured to generate refresh rate information corresponding to an image refresh rate of a target image to be displayed in the second period based on the control signal;
a gray scale calculator configured to generate gray scale information corresponding to grayscale values for the target image based on the input image data; and
a threshold determiner configured to determine the threshold value based on the refresh rate information, the grayscale information, and the optical waveform.
9. The display device of claim 8 , wherein the threshold determiner determines, as the threshold value, a value obtained by adding a reference value to a value of perceived luminance corresponding to a moment at which the image refresh rate is changed in the first period.
10. The display device of claim 8 , wherein the threshold determiner determines the threshold value based on a look-up table.
11. The display device of claim 8 , wherein the image controller further includes an optical waveform analyzer for generating the optical characteristic information based on the optical waveform.
12. The display device of claim 11 , wherein the optical waveform analyzer includes:
a domain converter configured to detect a frequency characteristic of the optical waveform to generate frequency information;
a luminance calculator configured to detect luminance values of the optical waveform to generate luminance information; and
an optical characteristic detector configured to detect a value of the flashing luminance based on the frequency information and the luminance information of the optical waveform to generate the optical characteristic information.
13. The display device of claim 12 , wherein the domain converter converts the optical waveform into a frequency domain through a fast Fourier transform.
14. The display device of claim 12 , wherein the luminance information includes a value of average luminance of the optical waveform.
15. The display device of claim 11 , wherein the image controller further includes:
a comparator configured to compare a value of the flashing luminance included in the optical characteristic information with the threshold value to generate a compared result data; and
a refresh rate control signal generator configured to generate the refresh rate control signal based on the compared result data.
16. The display device of claim 15 , wherein the refresh rate control signal generator applies a weight function to a difference between the value of the flashing luminance and the threshold value to generate the refresh rate control signal.