| 摘要 |
PURPOSE:To reduce the offset of a photodetector due to stray light getting into a prism by forming an anti-reflection film on the end part of the prism of an opposite side to a semiconductor laser element. CONSTITUTION:A black-colored transparent piece 9 is bonded on the end surface 10 of the prism of the opposite side to a sloping optical surface 6 and the surface of a semiconductor substrate 1 through the anti-reflection film 11 made of adhesive containing black dye for light absorption. Projecting light from the semiconductor laser element 8 is reflected by the end surface 6 of the prism 5, and is made incident to a recording medium. At that time, the stray light which was not reflected by the end surface 6 and is made incident to the prism 5 is absorbed by the film 11. Accordingly, the offset for signal light to a photodiode 2 can be reduced. |
