| 摘要 |
PURPOSE:To provide an optical path in the direction perpendicular to an optical recording medium by decreasing the chromatic aberrations when the wavelength of a light source is changed by a temp. change etc. CONSTITUTION:A semiconductor laser 1 and a photodetector 7 are formed via a buffer layer 47 on a substrate 2 and an aperture is formed in the lower part of a laser exit surface and photodetecting surface. A first glass layer 3 is packed in this aperture and a diffraction grating 4 is formed on the rear surface of this first glass layer 3. A second glass layer 5 is laminated under the first glass layer 3 and a condenser lens 6 of <=1mm aperture diameter consisting of a grating lens is formed on the rear surface of this second glass layer 5. As a result, the attenuation of the laser beam is lessened and the problem of the chromatic aberrations in the event of the change in the wavelength of the light source by the temp. change, etc., is not generated. The problem of the noise by the turn-back light is not generated. The point of the problem occurring in the formation of the optical path diagonal with the optical disk and the point of the problem in SCOOP structure are not generated. The size over the entire part is reduced. |
