| 摘要 |
PROBLEM TO BE SOLVED: To obtain a device which is small in size and which is suitable for a mass-production production by forming a diffraction grating, a semireflection surface and moreover a semiconductor laser or the like as a multi-functional prism while making them a chip to dispensing with the adjusting of the diffraction grating at the time of assembling of an optical pickup device. SOLUTION: A laser beam from a semiconductor laser 1A is diffracted into three beams of zero-order light beam and ±1st-order light beams in a diffraction grating 2A to be semitranmissively reflected by a semireflection surface 2B. Next, only the center part of the reflected light beams are transmitted by a diaphragm 3 to be convergingly image-formed on an optical disk 5 by an objective lens 4. Reflected light beams from the disk 5 successively pass the reverse path to be transmitted through the semi-reflection surface 2B and, moreover, transmitted through a transmission surface 2C to be reproduced by a light receiver 6A. Here, the adjusting of the diffraction grating at the time of assembling of the optical pickup device is made unnecessary by forming the diffraction grating 2A and the semireflection surface 2B made to be spatially arranged or the like as the multi-functional prism and by arranging it in the optical pickup device and the device which is small in size and is suitable for the mass-production is obtained. Moreover, the semiconductor laser or the like are make to be a chip and the chip can be built-up in the multi-functional prism. |
