| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a photodetecting circuit from which stable photo-detection outputs can be taken out by using an inexpensive mechanical constitution. <P>SOLUTION: A circuit XCT1 detects X-direction moving amounts and directions and another circuit YCT1 detects Y-direction moving amounts and directions in Y-direction. In the circuit XCT1, for example, the light emitted from an X-light emitter 100a is shielded by a rotary slit XSLT or received by means of X-light receivers 101a and 101b through the slit XSLT. The receivers 101a and 101b output voltages x1 and x2 corresponding to the quantities of the received light. As the voltages x1 and x2 drop, variable current sources 102a and 102b accelerate the drop of the voltages x1 and x2 by making currents flow to a grounding terminal from nodes x1 and x2. Consequently, comparable ranges of comparators 102a and 103b are expanded and stable photo-detection outputs can be taken out from the photodetecting circuit. <P>COPYRIGHT: (C)2003,JPO</p> |
