| 摘要 |
PURPOSE:To attain simple adjustment and to attain stable recording/reproduction and error check by dividing one laser luminous flux into two at an acoustooptic modulator to eliminate minute angle adjustment, applying pulse modulation to a diffracted beam in the laser luminous flux to use it as a recording spot and using other diffracted beam as a reading spot of constant output. CONSTITUTION:A cylindrical lens 3 is placed to stop only the minor axis direction of an incident luminous flux and the acoustooptic optical modulator 4 (A/O modulator) is placed at nearly a focal point. The A/O modulator 4 generates two diffracted beams by a signal from a controller 100, a modulation circuit 101 and a transducer 102. The diffracted beam from the A/O modulator 4 is converted into a nearly circular beam after the 2nd cyrindrical lens 5. Then the beam is stopped as two adjacent spots having a diameter of nearly 1mum on a disc 10 by a polarized prism 6, a 1/4 wavelength plate 7 and a stop lens 9. |
