Optical device

摘要

An optical device includes a base of ring shape, and an optical chip and a transparent plate both attached to the base. The upper surface of the base is formed with a tapered recess inclined downwardly from its flat portion toward the opening. A gap between the tapered recess and the transparent plate is formed with an adhesive layer. Even if a gap between the transparent plate and the flat portion of the base is narrowed, the adhesive layer with a great thickness present between the tapered recess and the lower surface of the transparent plate maintains the mechanical adhesion strength between the base and the transparent plate. A raised ring and a recessed ring prevent adhesive from entering a positioning hole and the opening.