Optical pickup and opto-magnetic signal reproducing apparatus

Abstract

An optical pickup includes a polarization component separation element which is formed as a unit or single piece of birefringence material. The separation element is not laminated obviating the need to carefully match the optical axes of the laminated pieces. Multiple reflections within the birefringent crystal which comprises the separation element improves the separation and resolution of the polarized components which are extracted from a laser beam reflected back off the media surface.

Description

technical field [0001] The invention relates to an optical sensor, in particular to an optical sensor used in a photomagnetic signal reproduction device. Background technique [0002] Fig. 1 shows an optical sensor for a magneto-optical disk device disclosed in U.S. Patent 5,479,387, issued December 26, 1995, to Ando et al. Wherein the optical sensor 1 is composed of a plurality of optical elements 2-10. The optical sensor 1 converges the laser beam emitted by the laser diode 2 and the laser beam reflected by the optical disk 11 via the grating element 3, the beam splitter 4, the collimating lens 5 and the objective lens 6, and passes through the Wollaston (Wollastou) prism 7 and the composite lens 8 on the photodetector 9 for imaging. [0003] However, this type of optical sensor has a disadvantage in that it is difficult to miniaturize the entire device. Another disadvantage of this arrangement is that reliability improvement is also difficult since a plurality of optic...

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Problems solved by technology

[0006] However, the above-mentioned optical sensor 21 is not suitable for reproduction of optical magnetic signals, because the optical sensor 21 is a non-polarization type optical system

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