| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve long distance detection of 10 mm or more with a resolution of not larger than 5 μm with a small sized and low cost device by eliminating usage of a magnetic sensor tend to be enlarged and cause a trouble in detection accuracy. <P>SOLUTION: A reflection plate 12 includes reflection surfaces sa and non-reflection surfaces sb alternately arranged in a moving direction of a moving body. A light receiving element 8 of a reflection type photo sensor 9 includes a plurality of light receiving sections 8a and 8b having respectively different light receiving regions in the moving direction of the moving body. Signals having different phase differences are output from the two light receiving sections 8a and 8b. Positions of the reflection plate 12 and the moving body are detected by applying, for example, linear value calculation to the two signals. Midpoint potential is also calculated by outputting three signals from a light receiving section which is divided into three. Linear value calculation with the reference of the mid-point potential may be implemented. In the light receiving section, linearity of the detection output can be improved by shielding a part of the light receiving region. <P>COPYRIGHT: (C)2013,JPO&INPIT |
