| 摘要 |
PURPOSE:To obtain a practical optical information recording and reproducing device with excellent reliability by providing an optical beam strength adjusting means at recording or reproduction and an optical beam irradiation energy adjusting means for irradiating an optical beam to a prescribed track of a medium, applying tracking control in standby. CONSTITUTION:An optical beam from a semiconductor laser 1 is formed into parallel light by a lens 2 and condensed on a disc 10 through a half mirror 3, a 1/4lambda plate 5' and an objective lens 6. The reflected light is received by a photodetector 8 at the half mirror 3 through the lens 6 and the 1/4lambda plate 5' again, and the information recording on the disc 10 is detected and tracking control is applied. A drive circuit 11 driving a semiconductor laser 1 applies a desired drive signal to a semiconductor laser by using the 1st optical beam irradiating energy adjusting means 12 in the standby state selected depending on the standby, recording and reproduction, the 2nd optical beam irradiating strength adjusting means 13 selected at recording and the 3rd optical beam irradiation strength adjusting means 14 selected at reproduction to obtain an oscillated output. |
