| 摘要 |
PROBLEM TO BE SOLVED: To provide a photosensor consisting of a nearly monochromatic point light source such as a light emitting diode(LED) mounted on a multiple element detector or a vertical cavity surface laser (VCSEL). SOLUTION: When the sensor 101 is placed near a mobile object 107 having the reflecting period pattern on the surface (like an optical disk), a signal usable for controlling the position of object is generated by the sensor 101. This sensor 101 executes the task to illuminate the object and to converge the light without using any optical constituting elements differently from other sensors such as often using lenses for projecting the light 105 emitted by the light source 102, converges the reflecting lights 106 from the object 107 and projects them to the photodetector 103. At this time, the self-image principle is utilized for detecting the motion of the object 107, in such a manner that the detector 103 is placed on the self-image plane of the object 107. |
