| 摘要 |
PROBLEM TO BE SOLVED: To simplify and miniaturize a device as a whole and at the same time obtain an appropriate focus error signal by simplifying alignment, when reducing the number of optical components and setting optical arrangement in an optical device, such as an optical pick-up. SOLUTION: This optical device is provided with an optical element, where a semiconductor laser LD, a reflection part 4 consisting of a plurality of reflection surfaces M1 , M2 , and M3 , and a photodetector PD are formed on the same semiconductor substrate 1 and a window structure element 20 that is provided, while covering the semiconductor laser LD, the reflection part 4, and the photodetector PD. The reflection part 4 is provided with a first reflection surface M1 for reflecting emitted light at least fromm the semiconductor laser and a second reflection surface M2 for applying a portion of returning light from a convergence means to the photodetector PD. Then, the window structure element 20 is provided with a light transmitting part 20w for transmitting a portion of the returning light and a light absorption part 23 for absorbing the returning light that, is directed towards the photodetector PD directly, without going through the reflection part 4. |
