| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a reflecting wavelength plate which functions as a wavelength plate even if a plurality of light sources which are different in wavelength are used, and to provide an optical pickup using the same. <P>SOLUTION: The reflection-type (1/4) wavelength plate 15 has, on a glass substrate 15e, a reflection film 15d and a subwavelength concave/convex structure 15c having a (1/4) wavelength plate function. Incident light LI from a light source is made incident from a face 15a of the reflection-type (1/4) wavelength plate 15, is refracted, passes through the inside of the subwavelength concave/convex structure 5c, is reflected at a boundary face with the reflection film 15d, passes through the inside again, is refracted on the face 15a, and is then emitted as emitted light LO. An optical axis 15p of the reflecting wavelength plate 15 is set in a direction of 45° to X, Y directions. Linear polarized light in the X direction is converted to circularly polarized light. The subwavelength concave/convex structure 15c makes the incident light transmit, without diffracting the incident light, in a periodic structure which is shorter than the wavelength of the incident light, and shows birefringence characteristics to the incident light. As different refraction indexes are shown in accordance with the polarization directions, structure parameters are adjusted, and phase differences are optionally set to achieve various wavelength plates. <P>COPYRIGHT: (C)2011,JPO&INPIT |
