Abstract: A light emitting device includes a light emitting element; a sub-mount including a sub-mount substrate with a front surface on which the light emitting element is disposed, and a back surface electrode disposed in a back surface that is on a back side of the front surface of the sub-mount substrate; a main-mount in which the sub-mount is disposed, the main-mount including a front surface metal pattern including a wiring electrode bonded to the back surface electrode via solder. The front surface metal pattern has a slit, in a plan view, at a position away from a disposition region in which the sub-mount is disposed.

Abstract: A light emitting device includes a light emitting element; a sub-mount including a sub-mount substrate with a front surface on which the light emitting element is disposed, and a back surface electrode disposed in a back surface that is on a back side of the front surface of the sub-mount substrate; a main-mount in which the sub-mount is disposed, the main-mount including a front surface metal pattern including a wiring electrode bonded to the back surface electrode via solder. The front surface metal pattern has a slit, in a plan view, at a position away from a disposition region in which the sub-mount is disposed.

Abstract: A light-emitting device includes: a substrate; a light-emitting element mounted on the substrate, with a surface opposite to a light-emitting surface facing the substrate; a first resin encapsulant which covers the light-emitting element such that at least part of the light-emitting surface is exposed; and a second resin encapsulant provided on and in contact with the first resin encapsulant and the light-emitting surface. The first resin encapsulant contains a light reflective material. The second resin encapsulant has a function of converting first light emitted by the light-emitting element into second light of different wavelength, and a function of mixing the first light and the second light.

Abstract: This invention provides an improved photodetector with the availability of various amplifiers and with a small circuit scale. A first light-receiving element PD.sub.1 is composed of a first impurity region of the n-type formed on a p-type semiconductor substrate and a second impurity region of the p-type formed at a surface zone of the first impurity region. A second light-receiving element PD.sub.2 is composed of the semiconductor substrate and a third impurity region of the n-type. PD.sub.1 and PD.sub.2 are connected together in series. Such arrangement makes it possible to reduce the circuit scale of photodetectors if a bipolar transistor or the like is used as an amplifier means. The photosensitivity becomes higher since reverse-bias voltages are applied to PD.sub.1 and PD.sub.2. Additionally, it is possible to set a wavelength band for light to be detected, according to the area ratio of PD.sub.1 and PD.sub.2.