| 摘要 |
PROBLEM TO BE SOLVED: To enhance the utilization efficiency of light, to facilitate miniaturization and to inexpensively improve productivity by providing a liquid crystal lens to be arranged between a beam splitter and a recording medium with a concave part or convex part formed by molding on one substrate of a liquid crystal cell and electrodes in part. SOLUTION: The concave part 13 is formed by molding on the inside surface of the one substrate of the transparent substrates facing each other. The inside surfaces of both substrates are respectively provided with the electrodes and the peripheries thereof are provided with sealing materials and liquid crystals are changed between the substrates, by which the liquid crystal lens 4 is constituted. The light emitted from a light source 1 passes the beam splitter 2, a phase difference plate 3 and the liquid crystal lens 4 and is condensed by a condenser lens 5. This light arrives at the first and second recording media 6, 7. The focus of the liquid crystal lens 4 is changed by impressing voltage on the liquid crystal lens 4 or changing the impression voltage, by which the lens is focused to the medium 6 or 7. The reflected light thereof is detected by a photodetector 8. As a result, the utilization efficiency of the light is enhanced, the miniaturization is facilitated and the inexpensive production with good productivity is made possible. |
