| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable coordinate input device with low power consumption without lowering the transmissivity of the display device. SOLUTION: A light source or light collection hole 11 is formed at one end side of the display surface of the liquid crystal display device to emit light in parallel to the display surface, and an optical sensor 7 is arranged at the other opposite end side; and some specific light is cut off to specify coordinates on the display screen. In this case, the light emitted from the light source or light collection hole 71 at the end part of the display surface passes through an optical waveguide oh the panel surface and impinges on the optical sensor 7 provided at the other end side of the display surface. The optical sensor 7 is provided on the glass substrate of the liquid crystal display device. A pen 3 cuts off the light impinging on the sensor and thus coordinates are specified. The sensor 7 varies in resistance value according to whether the light is present or not. When there are plural sensors, currents are supplied in order and the place where the light is made incident can be specified.</p> |
