| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical head device on which a polarization beam splitter of a flat plate having polarization separation characteristics of high S polarization reflectance and high P polarization transmittance is mounted and which has high light utilizing efficiency. <P>SOLUTION: In the polarization beam splitter of the optical head device, a multilayer film comprising at least two or more film materials having refractive indices different from each other is film-deposited on a surface of a transmissible substrate, polarization components orthogonal to each other are transmitted and reflected by utilizing difference of polarization transmission characteristics between a rise and a fall of a reflection band accompanying an incident angle of obliquely incident light, two reflection band multilayer film layers having long and short wavelengths as center wavelengths are provided on its separation surface, a rise on the long wavelength side of a short wavelength reflection band and a fall on a short wavelength side of a long wavelength reflection band are made to come close to each other and respective reflection and transmission polarization characteristics are multiplied to expand a polarization separation effective wavelength region. <P>COPYRIGHT: (C)2010,JPO&INPIT |
