| 摘要 |
PURPOSE:To make stable the recording and reproducting of the information signal, by providing the position detector detecting the recording and reproducing position toward the radial direction of the disc, and controlling the light power and frequency characteristics of reproducing signal at recording with the output signal. CONSTITUTION:The magnetic substance plate 27 is constituted with the same material as the transformer 25 to give a slope corresponding to the diameter of the disc 15. This magnetic substance plate 27 is located to the part of the gap 25' of the transformer 25 and it is moved toward the arrow D together with the optical carrier 17, to obtain the signal I' corresponding to the location of the magnetic plate 27. That is, the signal I' corresponding to the carrier position of the optical carrier 17, that is, the recording or reproduced position of the disc 15, can be obtained. The position signal detected at the position detector 22 is input to the recording power control circuit 24 and the compensation circuit 21 via the amplifier 23. Thus, the information signal stable for external and internal circumferences of the disc 15 can be recorded or reproduced. |
