| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a touch panel having an imaging function with high resolution, high speed operation and high gradation, and having an A/D conversion circuit mounted thereon.SOLUTION: A touch panel includes a plurality of pixels each provided with a display element and a photo sensor, an A/D converter to which a first potential is applied from a photo sensor, and a reading circuit. The A/D converter includes: an oscillation circuit which changes the oscillating frequency of a first signal to be generated in accordance with the first potential, and stops oscillating when a second potential is applied thereto from the reading circuit; and a counter circuit which generates a second signal having a count value determined in accordance with the oscillating frequency.</p> |
