| 摘要 |
PROBLEM TO BE SOLVED: To make acquirable a sufficiently large photocurrent signal from a light receiving element for detecting the rotational angle without causing any increase in load resistance by juxtaposing the light receiving element for detecting the rotational angle and a light receiving element for correcting the quantity of light sequentially along the rotational direction of a rotator in the illumination region of a light beam transmitted through the transmitting part of a rotary slit plate. SOLUTION: A light beam radiated from an LED 15 passes through the transmitting part of the M series track 12 on a rotary slit plate 22 and arrives at a light receiving element for the M series and a light receiving element for correcting the quantity of light. More specifically, the M series track 12 also serves as a track for correcting the quantity of light. Since the rotational angle is detected and the quantity of light of a light emitting means is corrected using the light transmitted through the rotational angle detection track 12 on the rotary slit plate 22, a light receiving element for correcting the quantity of light is not required to be arranged independently from the light receiving element for detecting the rotational angle. Consequently, the light receiving area of the light receiving element for detecting the rotational angle being arranged in the illumination region can be increased by a factor of about 2.
|
