| 摘要 |
PURPOSE:To detect the existence of a record on a turntalble and the size of the record by utilizing an identification device which identifies the inter-music part or groove parts of an autoplayer, and by installing a reflecting part of light from a photosensor on the turntable where said record is placed. CONSTITUTION:A covering 12, whose diameter is smaller than that of a turntable 1, is mounted on the upper surface of the turntable 1. A circumference part 13 of the turntable 1 is not covered with the covering 12, but is covered when a 30cm record 15 is placed on the table. The covering 12 has a larger diameter than a 17cm record 16. Also the covering has an annular reflection plate 14 attached on its upper surface. The reflection plate 14 is located at the place which the 17cm record 16 covers. When exposed to light a record mounting part shows the following three conditions where: The record is not set on the mounting part, both the outer circumference 13 and the reflection plate 14 reflect the light; The 17cm record is set, only the outer circumference 13 reflects the light; and the 30cm record is set, neither the outer circumference 13 nor the reflection plate 14 reflects the light. Detection of these three conditions can determine the size of the record. |
