Abstract: A driver circuit 3 feeds a pulse signal to an SSR 2 every half wave of alternating-current power from a commercial power source 4, and thereby separately controls the amounts of emitted light of LED groups 1x and 1y forming an LED unit 1, the LED groups 1x and 1y being connected in parallel in such a way as to point in different directions. That is, a first pulse signal for controlling the duration of light emission of the LED group 1x and a second pulse signal for controlling the duration of light emission of the LED group 1y are fed to the SSR 2 from the driver circuit 3.

Abstract: A driver circuit 3 feeds a pulse signal to an SSR 2 every half wave of alternating-current power from a commercial power source 4, and thereby separately controls the amounts of emitted light of LED groups 1x and 1y forming an LED unit 1, the LED groups 1x and 1y being connected in parallel in such a way as to point in different directions. That is, a first pulse signal for controlling the duration of light emission of the LED group 1x and a second pulse signal for controlling the duration of light emission of the LED group 1y are fed to the SSR 2 from the driver circuit 3.

Abstract: In order to provide a photothyristor having high breakdown voltage and less-varying light sensitivity by improving the sensitivity and the breakdown voltage of the device while maintaining the device small, the device includes a silicon substrate, a transistor portion including an anode region, a gate region and a cathode region and placed on a first main surface of the silicon substrate, a light-receiving portion for receiving light from the outside, and an electrode for establishing an ohmic contact between the anode region and the cathode region. The light receiving portion includes an oxygen-doped polysilicon film overlaid on the silicon substrate through a transparent insulating film and is disposed to surround the transistor portion. The electrode is placed above the transistor portion and has a double-structure consisting of a center portion and an outer portion surrounding the center portion, and the center portion and the outer portion are electrically connected.

Abstract: In order to provide a photothyristor having high breakdown voltage and less-varying light sensitivity by improving the sensitivity and the breakdown voltage of the device while maintaining the device small, the device includes a silicon substrate, a transistor portion including an anode region, a gate region and a cathode region and placed on a first main surface of the silicon substrate, a light-receiving portion for receiving light from the outside, and an electrode for establishing an ohmic contact between the anode region and the cathode region. The light receiving portion includes an oxygen-doped polysilicon film overlaid on the silicon substrate through a transparent insulating film and is disposed to surround the transistor portion. The electrode is placed above the transistor portion and has a double-structure consisting of a center portion and an outer portion surrounding the center portion, and the center portion and the outer portion are electrically connected.

Abstract: A red color laser diode 13 is die-bonded onto a silicon submount photodiode chip 11 having a insulating film 4 on the surface thereof. The silicon submount photodiode chip 11 receives a light beam radiated from a back side 13b of the red color laser diode 13 for monitoring an output of a light beam radiated from a front side 13a of the red color laser diode 13. The insulating film 4 of the silicon submount photodiode chip 11 is provided with a hole 14 located beneath an electrode 12 that die-bonds the red color laser diode 13 onto the silicon submount photodiode chip 11. Heat generated by the red color laser diode 13 is easily conducted to the silicon submount photodiode chip 11 through the hole 14 not covered with the insulating film 4 and discharged therefrom, which enables prevention of thermal destruction.

Abstract: A photodiode includes a high-concentration first conductivity-type substrate, a low-concentration first conductivity-type epitaxial layer formed on one face of the substrate, a second conductivity-type diffusion layer formed in the epitaxial layer, the diffusion layer serving as a light-receptive section, a pair of electrodes comprising a cathode and an anode, one of the pair of electrodes being mounted on the second conductivity-type diffusion layer and the other being mounted on another face of the substrate or one of the pair of electrodes being mounted on the second conductivity-type diffusion layer and the other being mounted on the epitaxial layer except the diffusion layer, and a third electrode mounted in an outer periphery or an inner periphery of a region occupied by the second conductivity-type diffusion layer on the epitaxial layer, the third electrode not contacting the pair of electrodes.

Abstract: A photodiode includes a high-concentration first conductivity-type substrate, a low-concentration first conductivity-type epitaxial layer formed on one face of the substrate, a second conductivity-type diffusion layer formed in the epitaxial layer, the diffusion layer serving as a light-receptive section, a pair of electrodes comprising a cathode and an anode, one of the pair of electrodes being mounted on the second conductivity-type diffusion layer and the other being mounted on another face of the substrate or one of the pair of electrodes being mounted on the second conductivity-type diffusion layer and the other being mounted on the epitaxial layer except the diffusion layer, and a third electrode mounted in an outer periphery or an inner periphery of a region occupied by the second conductivity-type diffusion layer on the epitaxial layer, the third electrode not contacting the pair of electrodes.

Abstract: A red color laser diode 13 is die-bonded onto a silicon submount photodiode chip 11 having a insulating film 4 on the surface thereof. The silicon submount photodiode chip 11 receives a light beam radiated from a back side 13b of the red color laser diode 13 for monitoring an output of a light beam radiated from a front side 13a of the red color laser diode 13. The insulating film 4 of the silicon submount photodiode chip 11 is provided with a hole 14 located beneath an electrode 12 that die-bonds the red color laser diode 13 onto the silicon submount photodiode chip 11. Heat generated by the red color laser diode 13 is easily conducted to the silicon submount photodiode chip 11 through the hole 14 not covered with the insulating film 4 and discharged therefrom, which enables prevention of thermal destruction.