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US 6,151,288 AGranted
Optical head assembly
AssigneeSankyo Seiki Mfg. Co., Ltd.
InventorsYuichi Takei, Tadashi Takeda, Yoshio Hayashi
Life of this patent
Estimating the term…
Abstract
An optical head assembly comprises a laser light source, an objective lens for converging a laser light emitted from the laser light source on an optical recording medium, an optical detector for detecting a returning light from the optical recording medium, a diffraction unit mounted in an optical path between the laser light source and objective lens for positioning multiple diffraction grating means, a base of the optical head assembly for supporting the objective lens, the laser light source and the optical detector, and a diffraction grating unit retaining portion formed on the base for holding the diffraction grating unit.
Claims11
An optical head assembly comprising:
- a laser light source;
- an objective lens for converging a laser light emitted from said laser light source on an optical recording medium;
- an optical detector for detecting a returning light from said optical recording medium;
- a diffraction grating unit mounted in an optical path between said laser light source and said objective lens for positioning multiple diffraction grating means;
- a base of the optical head assembly for supporting said objective lens, said laser light source, and said optical detector;
- and
- a diffraction grating unit retaining portion formed on said base for holding said diffraction grating unit, said diffraction grating unit having a holder for positioning and holding each of said diffraction grating means, said holder having a circumferential surface which extends along an optical axis of said optical head assembly, and said diffraction grating unit retaining portion having a positioning portion for determining a mounting position of said diffraction grating unit in said optical axis direction of said optical head assembly and a guiding plane with which said circumferential surface fittingly contacts when said diffraction grating unit is turned around an axial line thereof;
- said multiple diffraction grating means including separate diffraction-grating optical elements;
- said diffraction grating unit having a common holder for positioning and holding each of said diffraction-grating optical elements, said common holder having separate positioning portions for positioning each of said diffraction-grating optical elements so that a distance between one and the other of said diffraction-grating optical elements is substantially identical and a relationship of diffraction patterns of one and the other of said diffraction-grating optical elements is also identical when said diffraction grating unit is turned around the axial line thereof.
6 more elements
An optical head assembly comprising:
- a laser light source;
- an objective lens for converging a laser light emitted from said laser light source on an optical recording medium;
- an optical detector for detecting a returning light from said optical recording medium;
- a diffraction grating unit mounted in an optical path between said laser light source and said objective lens for positioning multiple diffraction grating means;
- a base of the optical head assembly for supporting said objective lens, said laser light source, and said optical detector;
- a diffraction grating unit retaining portion formed on said base for holding said diffraction grating unit,
- said multiple diffraction grating means including a first and second diffraction-grating optical elements, said first diffraction-grating optical element being mounted apart from said second diffraction-grating optical element, said first diffraction-grating optical element having a diffraction property of guiding the returning light to the optical detector, and said second diffraction-grating optical element having a diffraction property of splitting the laser light into multiple laser beams;
- a holder for positioning and holding said multiple diffraction grating means, said holding having a cylindrical portion having an outer circumferential side surface which serves as said circumferential surface, and said diffraction grating unit retaining portion includes a hole to which said cylindrical portion is inserted and an inner circumferential surface of which serves as said guiding plane.
5 more elements
Dependencies are inferred from the claim text.