Patent ID: 7889623

Claim:
An optical pickup, comprising: a light source for emitting at least a light beam at wavelength of 405 nm, a light beam at wavelength 640 nm, and a light beam at wavelength 780 nm; a polarized beam splitter; a λ/4 wave plate and photodetector; and a reflecting mirror, in which a light path is formed to and from said light source, said polarized beam splitter, said λ/4 wave plate and photodetector and said reflecting mirror; said reflecting mirror comprising: a first reflective multi-layer coating formed on a substrate plate by alternately depositing a low refractivity layer and a first high refractivity layer absorptive of a wavelength of 405 nm having a refractivity higher than said low refractivity layer of the first reflective multi-layer coating; and a second reflective multi-layer coating formed at a light incident side of said first reflective multi-layer coating, by alternately depositing a low refractivity layer and a non-absorptive second high refractivity layer having a refractivity higher than said low refractivity layer of the second reflective multi-layer coating but lower than said first high refractivity layer in said first reflective multi-layer coating; wherein an incident light beam at a wavelength of 405 nm is reflected off by said second reflective multi-layer coating while incident light beams at wavelengths of 640 nm and 780 nm are reflected off by cooperative actions of said first and second reflective multi-layer coatings; and wherein said second reflective multi-layer coating reflects off part of incident light beams at wavelengths of 640 nm and 780 nm.