HOLOGRAM LENS AND ITS PRODUCTION AND OPTICAL SYSTEM SIGNAL USING THIS HOLOGRAM LENS

摘要

PURPOSE:To obtain the hologram lens and obtain the focusing laser beam to be radiated to an optical recording medium by radiating the focusing laser beam and divergent laser beam to the recording medium thereby forming their interference images. CONSTITUTION:Part of the laser beam is reconstructed as a spherical wave beam 17 by way of splitter 13, expander 14, mirror 15 and lens 11. Also, part of the beam is irradiated as a divergent beam 21 to medium 10' by way of a mirror 18, lens 19, mirror 20 and the light transmission part 12a of a mask 12. In the medium 10', the interference image with the beams 17, 21 which are mutually in in-line relation is recorded. This is developed to obtain a hologram lens 10. In the reconstruction head, the beam reflected from the recording medium 7 passes through the hologram 10 and returns to the semiconductor laser light source 1. According to the quantity of the beam having returned, the intensity of its oscillation beam is modulated and the intensity of the oscillation beam going toward the back from the light source 1 is detected by a photodetector 51, which in turn outputs the reconstruction signal.