| 摘要 |
PURPOSE:To stably attain synchronism of signals and to make it possible to perform satisfactory recording and reproduction by providing a main scale of an optical encoder for measuring the shift distance of an optical recording medium on the optical recording medium itself. CONSTITUTION:This optical recording medium is a card type recording medium (optical card) 1 and has a recording region 2 with a performat and the main scale 4 of an optical encoder at the peripheral part of the recording region 2. Since the shift of this optical card 1 at the time of reproduction is a reciprocal rectilinear motion, a linear encoder is used as the encoder, accordingly the main scale 4 is also a linear scale. |
