| 摘要 |
<p>PROBLEM TO BE SOLVED: To detect a rotation angle of a rotation shaft along an entire periphery of 360 deg. and also to improve durability by detecting without contact. SOLUTION: A disk-like translucent plate 4 is fixed in a slant state to a rotation shaft 3 provided to pass through a base 1 and an outer case 2. The translucent plate 4 is a planar transparent plate with a predetermined thickness and a refractive index of (n), it is designed to refract light incident slantly with respect to a direction perpendicular to a surface. A gradient angle is set toθ. An LED(light emitting diode) 5 for projecting a light beam P along an axial line of the rotation shaft 3 and a PSD (semiconductor position detection element) 6 for receiving the light beam P are provided oppositely across the translucent plate 4. When the translucent plate 4 rotates according to rotation of the rotation shaft 3, a direction where the light beam P is refracted by the plate 4 varies, and by detecting this by the PSD 6, corresponding rotation angles can be detected along the entire periphery without contact.</p> |
