| 摘要 |
<p>PURPOSE:To make a beam from a light source body go out effectively from the outside circumferential face without closing up said beam in a photoconductive ring, by making the inside circumferential face of the photoconductive ring eccentric from the outside circumferential face, and burying the light source body in a thick part of the photoconductive ring formed by the eccentricity. CONSTITUTION:A titled device can be applied to a light source device, etc. of a photocoupler which is used for connecting a signal of a switch device provided on a hub part of a steering wheel and an on-vehicle apparatus, and an outside circumferential face 7 of an annular photoconductive ring 1 formed by a light transmitting material is made eccentric against an inside circumferential face 8, therefore, in the process where a beam emitted from a light emitting diode 5 is totally reflected between the outside circumferential face 7 of the photoconductive ring 1 and the inside circumferential face 8 and is propagated, an angle of the beam reaching the outside circumferential face 7 becomes small gradually, and at the point of time when said angle becomes smaller than a critical angle phi0, light goes out to the outside from the outside circumferential face 7.</p> |
