| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical element having the function of a 1/4 wavelength plate, the function of limiting an aperture, and the function of correcting a wave front aberration to manufacture the compact optical head of high light utilization efficiency compatible to a CD and a DVD by one objective lens with high productivity. <P>SOLUTION: This optical element is constituted by fixing, from both sides sandwiching an organic thin film 12 having double refraction, an aperture limiting element 11 provided with a center part for transmitting the lights of two wavelengths and a peripheral part formed around the center part for reflecting or diffracting one of the lights, and a wave front aberration correction element 14 provided with a ring-like groove for correcting a wave front to be integral by an adhesive 13. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
