| 摘要 |
PURPOSE:To have the symmetric property, to minimize the number of parts, to be small-sized and light-weight and to execute the low-price as much as possible by arranging the diffraction grating between the light source and the focusing lens, dividing the return light from the recording support with the diffraction grating and guiding it to the light detecting device. CONSTITUTION:After the light to emit from a semiconductor laser 7 is collimat ed by a collimator lens 4 and transmits a diffraction grating 3, a zero-order light proceeds in the direction orthogonal to a recording surface 1a of a record ing support 1, collected by an objective lens 2 and irradiated on the recording surface 1a. The irradiated light, after the light is modulated at the recording information part on the recording support 1 and focused by the objective lens 2, is diffracted by the diffraction grating 3. The light diffracted by the diffrac tion grating 3 is focused on detecting devices 6a and 6b and the information on the recording support 1 can be reproduced. Thus, the symmetric property of the pick-up can be realized and the device can be made smaller-sized, light- weight and low-priced. |
