Optical head device with diffraction grating for separating a light beam incident on an optical recording medium from a light beam reflected therefrom
First Claim
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1. An optical head device comprising:
- a light source;
condensing means for condensing a light beam emitted from said light source on an optical recording medium;
a diffraction grating arranged in the optical path of an incident light beam entering the recording medium from said light source to transmit the incident light beam through said diffraction grating and to diffract light reflected from the recording medium for separating the reflected light from the incident light beam; and
a photodetector for receiving the light diffracted by said diffraction grating, said photodetector including a light receiving surface which is divided into a plurality of areas by at least a dividing line extending substantially in a direction in which a spot of the light diffracted by said diffraction grating moves on said light receiving surface due to the wavelength fluctuation of said light source.
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Abstract
An optical head device comprises a light source, condensing optics for condensing a light beam emitted from the light source on an optical recording medium, a photodetector for detecting the light of the light beam reflected from the recording medium, and a beam splitter having a diffraction grating arranged in the optical path of the light beam entering the recording medium from the light source along a plane substantially perpendicular to the optical axis of the incident light beam to cause the light reflected light from the recording medium to be diffracted by the diffraction grating and directed to the photodetector.
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Citations
20 Claims
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1. An optical head device comprising:
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a light source; condensing means for condensing a light beam emitted from said light source on an optical recording medium; a diffraction grating arranged in the optical path of an incident light beam entering the recording medium from said light source to transmit the incident light beam through said diffraction grating and to diffract light reflected from the recording medium for separating the reflected light from the incident light beam; and a photodetector for receiving the light diffracted by said diffraction grating, said photodetector including a light receiving surface which is divided into a plurality of areas by at least a dividing line extending substantially in a direction in which a spot of the light diffracted by said diffraction grating moves on said light receiving surface due to the wavelength fluctuation of said light source. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification