| 摘要 |
PURPOSE:To prevent abnormal noise ad useless oscillation by mounting an electromagnetic shield body having transmission on a base of the light receiving device having the base, a light receiving element and a plastic cover so as to cover the circumference of the light receiving element. CONSTITUTION:The light receiving device 1 is provided with a base 2, three light receiving elements 3, a transparent cover 4 accommodating them, and a transparent electromagnetic shield body 5 mounted on the base 2. The shield is formed semi-spherically by a metal net and both ends of metallic wires 31 of the metal net are soldered to a shield plate of a lower surface of the base 2 to cover all of the three light receiving elements 3. A numerical aperture of the shield body 5 is secured at least to be 88% or over without impairing the transmittance of the signal from an infrared ray microphone or the like and able to effectively shield an external electromagnetic wave. Thus, the signal transmittance is improved and the external electromagnetic wave is surely interrupted without impairing the performance of the light receiving elements 3. |
