| 摘要 |
<p>PURPOSE:To control the ON/OFF of a heat source smoothly by detecting external information in a display device provided with a display panel holding a display body having heat/electricity/light effects between a pair of substrates and a light pen having the heat source. CONSTITUTION:A speed sensor 27 is fitted to the leading end of a light pen 23 to control the output of a semiconductor laser in accordance with the speed of the light pen 23. A spherical rotary body 30 having at least a pair of N and S poles is fitted to the leading end of the speed sensor 27, and since the rotary body 30 is rotated in accordance with the movement of the light pen 23, the frequency of a detected voltage Vc is changed approximately in proportion to the moving speed of the light pen. The detected voltage Vc is converted into a voltage Vs by a frequency/voltage converting circuit 25 and the voltage Vs having a value approximately proportional to the moving speed of the light pen is inputted to a semiconductor laser driving circuit 3. The output of the semiconductor laser is controlled by speed information obtained by the speed sensor and temperature information, so that the writing line width can be exactly controlled.</p> |
