Abstract: A manufacturing method for an optical deflector, in which a piezoelectric film layer having a uniform film thickness is formed on a substrate layer, includes forming a cavity to open to a SiO2 layer side in a forming region of an outside piezoelectric actuator by etching an SOI wafer from the SiO2 layer side, covering an exposed surface of the cavity with a SiO2 layer, and joining the SiO2 layer of the SOI wafer and a support layer of an SOI wafer to manufacture an SOI wafer in which the cavity is enclosed. Next, after a recess is formed on a back side of the SOI wafer, anisotropic dry etching is carried out from the back side in a depth direction of the recess to remove the SiO2 layer.

Abstract: In a light emitting device, in a bottom surface of a cavity of a Si substrate, slit-shaped through holes and through electrodes that fill the through holes are provided at a position facing a first element electrode of a light emitting element. A length of an upper surface of the through electrode in a long axis direction is larger than a height of the through electrode in a thickness direction of the Si substrate. A joining layer having a shape corresponding to a shape of the upper surface of the through electrode is disposed between the first element electrode of the light emitting element and the upper surface of the through electrode facing the first element electrode. The entire upper surface of the through electrode is joined to the first element electrode via the joining layer.