| 摘要 |
PURPOSE:To reproduce information accurately and prevent the damage of the record, by using the ultrasonic wave transmission and receiving element to transmit the ultrasonic wave to the sound groove of the record disc and by using the reflection wave to reproduce information. CONSTITUTION:Turntable 2 is fitted to the shaft of the rotation of driving motor 1, and the surface of record disc 3 is soaked in water or the liquid of CS2 and so on. Supporting part 4 of ultrasonic wave transmission and receiving elements 8 and 8' is connected to arm 5, and elements 8 and 8' are so controlled by stylus 6 that they are placed on the sound groove. Elements 8 and 8' consist of acoustic lens 9 of sapphire and so on and thin film piezoelectric element 10 of ZnO and so on which is formed on the one-side face of lens 9. Pulses of several G Hz generated from wave transmitting circuit 11 drive piezoelectric element 10 through circulator 13 and are condensed to the slope of the sound groove by acoustic lens 9. The reflection signal is converted to an electric signal by piezolelectric element 10 and is sent to receiving circuit 12. As a result, information is reproduced accurately, and the damage of the record is prevented. |
