Touch panel and method for driving the same
View Patent ↗A touch panel having high reading accuracy of an object to be detected is provided. In a method for driving a touch panel which is provided with a photo sensor in a pixel, an image is displayed in a display portion of a touch panel, a detection region is determined by detecting approach or contact of an object to be detected in a state in which the image is displayed, and the object to be detected is read while substantially equalizing the intensity of light of pixels in the detection region per unit time and unit area. The intensity of light of the pixels per unit time and unit area, which is to be substantially equal, is preferably the maximum intensity of light in the detection region before adjustment, more preferably, the intensity of light for white display.
1. A method for driving a touch panel which is provided with photo sensors in pixels, comprising the steps of:
displaying an image in a display device comprising a plurality of pixels;
determining a detection region by detecting light reflected by an object to be detected in a state in which the image is displayed;
turning on transistors connected to the photo sensors which are provided in the detection region;
turning off transistors connected to the photo sensors which are provided outside the detection region; and
reading the object to be detected while equalizing gray scale levels of pixels in the detection region, turning on the transistors connected to the photo sensors which are provided in the detection region, and turning off the transistors connected to the photo sensors which are provided outside the detection region.
2. The method for driving a touch panel according to claim 1 , wherein video signals supplied to the pixels in the detection region while the reading is performed are equal to each other.
3. A touch panel operated by the method for driving a touch panel according to claim 1 .
4. The touch panel according to claim 3 , wherein the plurality of pixels emitting same color are provided at positions shifted from each other.
5. The touch panel according to claim 3 , wherein the plurality of pixels are arranged in delta arrangement.
6. The touch panel according to claim 3 , wherein the display device is a liquid crystal display device.
7. The touch panel according to claim 6 , wherein a cold-cathode fluorescent lamp is used as a backlight of the liquid crystal display device.
8. The touch panel according to claim 6 , wherein a white light-emitting diode is used as a backlight of the liquid crystal display device.
9. The touch panel according to claim 6 , wherein a liquid crystal layer of the liquid crystal display device includes a liquid crystal which exhibits a blue phase.
10. The method for driving a touch panel according to claim 1 , wherein the detection region is determined as a region in which the photo sensors are irradiated with the light whose intensity is greater than or equal to a threshold value of the photo sensors.
11. A method for driving a touch panel which is provided with photo sensors in pixels, comprising the steps of:
displaying an image in a display device comprising a plurality of pixels;
determining a detection region by detecting light reflected by an object to be detected in a state in which the image is displayed;
turning on transistors connected to the photo sensors which are provided in the detection region;
turning off transistors connected to the photo sensors which are provided outside the detection region; and
reading the object to be detected while equalizing gray scale levels of pixels in the detection region to a gray scale level of the brightest pixel among the pixels in the detection region, turning on the transistors connected to the photo sensors which are provided in the detection region, and turning off the transistors connected to the photo sensors which are provided outside the detection region.
12. The method for driving a touch panel according to claim 11 , wherein video signals supplied to the pixels in the detection region while the reading is performed are equal to each other.
13. A touch panel operated by the method for driving a touch panel according to claim 11 .
14. The touch panel according to claim 13 , wherein the plurality of pixels emitting same color are provided at positions shifted from each other.
15. The touch panel according to claim 13 , wherein the plurality of pixels are arranged in delta arrangement.
16. The touch panel according to claim 13 , wherein the display device is a liquid crystal display device.
17. The touch panel according to claim 16 , wherein a cold-cathode fluorescent lamp is used as a backlight of the liquid crystal display device.
18. The touch panel according to claim 16 , wherein a white light-emitting diode is used as a backlight of the liquid crystal display device.
19. The touch panel according to claim 16 , wherein a liquid crystal layer of the liquid crystal display device includes a liquid crystal which exhibits a blue phase.
20. The method for driving a touch panel according to claim 11 , wherein the detection region is determined as a region in which the photo sensors are irradiated with the light whose intensity is greater than or equal to a threshold value of the photo sensors.
21. A method for driving a touch panel which is provided with photo sensors in pixels, comprising the steps of:
displaying an image in a display device comprising a plurality of pixels;
determining a detection region by detecting light reflected by an object to be detected in a state in which the image is displayed;
turning on transistors connected to the photo sensors which are provided in the detection region;
turning off transistors connected to the photo sensors which are provided outside the detection region and
reading the object to be detected while performing white display in the detection region, turning on the transistors connected to the photo sensors which are provided in the detection region, and turning off the transistors connected to the photo sensors which are provided outside the detection region.
22. The method for driving a touch panel according to claim 21 , wherein video signals supplied to pixels in the detection region while the reading is performed are equal to each other.
23. A touch panel operated by the method for driving a touch panel according to claim 21 .
24. The touch panel according to claim 23 , wherein the plurality of pixels emitting same color are provided at positions shifted from each other.
25. The touch panel according to claim 23 , wherein the plurality of pixels are arranged in delta arrangement.
26. The touch panel according to claim 23 , wherein the display device is a liquid crystal display device.
27. The touch panel according to claim 26 , wherein a cold-cathode fluorescent lamp is used as a backlight of the liquid crystal display device.
28. The touch panel according to claim 26 , wherein a white light-emitting diode is used as a backlight of the liquid crystal display device.
29. The touch panel according to claim 26 , wherein a liquid crystal layer of the liquid crystal display device includes a liquid crystal which exhibits a blue phase.
30. The method for driving a touch panel according to claim 21 , wherein the detection region is determined as a region in which the photo sensors are irradiated with the light whose intensity is greater than or equal to a threshold value of the photo sensors.