| 摘要 |
PROBLEM TO BE SOLVED: To obtain a small-size and lightweight optical head device excellent in light condensing characteristics on an optical disk by mounting a liquid crystal and-sealing element wherein the extent of fluctuation of the retardation value in the surface thereof is small over the wide range of temperature on the optical head device. SOLUTION: The liquid crystal end-sealing element constituted in such a manner that two transparent substrates 501 and 502 between which a liquid crystal layer 508 is interposed are sealed by a sealing material 507 at the periphery part thereof and a bubble 510 is interposed between the substrates together with the liquid crystal layer 508 is disposed in the optical path between a light source and an object lens of the optical head device. |
