Abstract: A light emitting device includes a semiconductor laser element, a base member, and a cover. The base member includes a first alignment mark, a second alignment mark, a third alignment mark, and a fourth alignment mark. The base member has a disposition surface on which the semiconductor laser element is disposed. The cover is bonded to the base member to define a closed space in which the semiconductor laser element is arranged. The first alignment mark and the second alignment mark are arranged outside the closed space. The third alignment mark and the fourth alignment mark are arranged inside the closed space. A straight line connecting the first alignment mark and the second alignment mark is parallel to a straight line connecting the third alignment mark and the fourth alignment mark.

Abstract: A light emitting device, free from change of color even when the wavelength of a light emitting element shifts, includes a light emitting element (106) for emitting primary light having an intensity peak at a wavelength shorter than 400 nm; a silicone resin (111) provided to embed the light emitting element; and a fluorescent element (110) contained in the silicone resin to absorb the primary light and release visible light.

Abstract: A light emitting device, free from change of color even when the wavelength of a light emitting element shifts, includes a light emitting element (106) for emitting primary light having an intensity peak at a wavelength shorter than 400 nm; a silicone resin (111) provided to embed the light emitting element; and a fluorescent element (110) contained in the silicone resin to absorb the primary light and release visible light.

Abstract: A light emitting device, free from change of color even when the wavelength of a light emitting element shifts, includes a light emitting element (106) for emitting primary light having an intensity peak at a wavelength shorter than 400 nm; a silicone resin (111) provided to embed the light emitting element; and a fluorescent element (110) contained in the silicone resin to absorb the primary light and release visible light.

Abstract: A light emitting device, free from change of color even when the wavelength of a light emitting element shifts, includes a light emitting element (106) for emitting primary light having an intensity peak at a wavelength shorter than 400 nm; a silicone resin (111) provided to embed the light emitting element; and a fluorescent element (110) contained in the silicone resin to absorb the primary light and release visible light.

Abstract: An LED and a photo-diode are arranged such that they are optically coupled with each other. The first terminal to which a power supply voltage is applied is connected to the anode of the LED. Between the cathode of the LED and the second terminal for outputting an output signal, there is provided a constant current circuit for allowing a constant current to flow into the LED. To the cathode of the LED, connected is the collector of an NPN transistor, to the emitted of which the second terminal is connected. Light emitted from the LED is detected and converted into an current signal by the photo-diode. The current signal generated by the photo-diode is amplified by an amplifying circuit. A signal output from this amplifying circuit is supplied to the base of the NPN transistor, thereby controlling ON/OFF operation of the transistor. Between the second terminal and the ground point located outside the device, connected is a load resistor.