| 摘要 |
PURPOSE:To improve the directivity, by providing the means to limit the spread angle of emitting light from the light emitting diode. CONSTITUTION:The light emitting diode 2 is mounted on the cylinder 1 consisting of the light emitting diode housing section 11, light flux limiting section 12 and opening 13. The light flux limiting section 12 determines the maximum dispersion angle of light flux together with the light emitting diode housing section 11 so that the angel has the specified value of d/l. The photodetector, the same as the emitter, introduces incident light to the photodiode 4 via the incident light flux limiting cylinder 3. |
