Abstract: Provided is an optical pickup device which suppresses the decrease of light amount and performs conversion to circular polarization light, wherein the optical pickup device includes a beam splitter and a raising mirror on each of which a layered member is formed, and the optical pickup device satisfies conditional expressions relating to intensities of S-polarized light and P-polarized light with respect to the beam splitter of a laser beam emitted from a semiconductor laser element, reflectances of S-polarized light and P-polarized light on the beam splitter, a reflection phase difference obtained by subtracting a phase of S-polarized light from a phase of P-polarized light after the reflection, reflectances of S-polarized light and P-polarized light on the raising mirror, and a reflection phase difference obtained by subtracting a phase of S-polarized light from a phase of P-polarized light after the reflection.

Abstract: A monitor optical device has a first region and a second region. The first region transmits part of light beam emitted from a light source to introduce the transmitted light beam to a monitor device. The second region reflects the remainder of the light beam to introduce the reflected light beam to an optical disk. The first region is formed at least within the second region.

Abstract: A non-polarizing beam splitter has a first prism; one or more ground layer(s) made of a dielectric material which is (are) formed on a slant face of the first right angle prism; an Au layer having thickness of 13 to 35 nm which is formed on the ground layer; one or more protective layer(s) made of a dielectric material which is (are) formed on the Au layer; and a second prism which is jointed to an outermost layer of the protective layer via adhesive. The non-polarizing beam splitter divides light at wavelength of 640 nm to 820 nm into transmission light and reflection light by a predetermined ratio.

Abstract: A non-polarizing beam splitter has a first prism; one or more ground layer(s) made of a dielectric material which is (are) formed on a slant face of the first right angle prism; an Au layer having thickness of 13 to 35 nm which is formed on the ground layer; one or more protective layer(s) made of a dielectric material which is (are) formed on the Au layer; and a second prism which is jointed to an outermost layer of the protective layer via adhesive. The non-polarizing beam splitter divides light at wavelength of 640 nm to 820 nm into transmission light and reflection light by a predetermined ratio.

Abstract: A monitor optical device has a first region and a second region. The first region transmits part of light beam emitted from a light source to introduce the transmitted light beam to a monitor device. The second region reflects the remainder of the light beam to introduce the reflected light beam to an optical disk. The first region is formed at least within the second region.