Patent ID: 6327237
Filing Date: 2001-12-04
Classification: G11B

Abstract:
A method of manufacturing an optical pickup for recording or reproducing information on an optical disc, comprising the steps of:selecting a first light source for emitting a beam having a far-field pattern of an elliptic shape and a predetermined long wavelength and propagated in a TE mode in which light is polarized in a first polarizing direction along a minor axis of the elliptic shape and or a light source for emitting a beam having a far-field pattern of an elliptic shape and a predetermined short wavelength lower than the predetermined long wavelength and propagated in a TM mode in which light is polarized in a second polarizing direction along a major axis of the elliptic shape and perpendicular to the first polarizing direction in the TE mode;providing a shaping prism for changing the elliptic shape of the beam from the first light source or the second light source, whichever is selected, into a circular shape;arranging a beam splitter in such a way as to transmit the beam from the selected light source and to reflect a beam having a polarizing direction different from that of the beam from the selected light source by 90 degrees;determining whether the first light source or the second light source has been selected, and arranging a half-wave plate for rotating the polarizing direction of the beam of the selected light source by 90 degrees between the selected light source and the beam splitter;arranging a quarter-wave plate for transmitting the beam from the beam splitter to the optical disc and for changing a beam reflected from the optical disc into the beam whose polarizing direction is different from that of the beam from the selected light; andarranging a photodetector receiving the beam reflected from the beam splitter.