Optical-pickup device and tilt-detecting method thereof
AssigneeRicoh Company, Ltd.
InventorsHideaki Hirai, Hiroshi Koide, Hiroshi Akiyama
Life of this patent
Estimating the term…
Abstract
An optical-pickup device includes a plurality of light sources, an objective lens for converging light from the plurality of light sources on an optical disc, and at least one light-receiving element for receiving light reflected by the optical disc. A light source of the plurality of light sources, which light source is not used for recording/reproducing, is used for detecting relative tilt between the optical disc and the objective lens.
Claims34
An optical-pickup device, comprising:
- a plurality of light sources;
- an objective lens for converging light from said plurality of light sources on an optical disc;
- and
- at least one light-receiving element for receiving light reflected by said optical disc,
- wherein a light source of said plurality of light sources, which light source is not used for recording/reproducing, is used for detecting a relative tilt between said optical disc and said objective lens.
An optical-pickup device, comprising:
- an objective lens for converging light, emitted from a light source which is used for tilt detection, to an optical disc;
- and
- an actuator for said objective lens such that no optical-axis deviation develops between the ideal optical axis and the optical axis of said objective lens at a time of tracking when said actuator is used.
A tilt-detecting method, comprising the steps of:
- a) using any one of a plurality of light sources as a light source for detecting a relative tilt between an optical disc and an objective lens;
- and
- b) causing, at a time of tilt detection, said light source to emit light obtained as a result of intensity modulation with a waveform including an alternating-current component, the basic frequency of said waveform being fixed.
An optical-pickup device which can record information on any one of a plurality of types of optical recording media, the thicknesses of the substrates of said plurality of types of optical recording media being different from each other, and wavelengths used for performing recording/reproducing on said plurality of types of optical recording media being different from each other, and can reproduce information recorded on said one of said plurality of types of optical recording media, said device comprising:
- a semiconductor laser which emits laser light of a first wavelength;
- a wavelength-converting element which produces laser light of a second wavelength which is half of said first wavelength;
- a converging optical system which can focus the laser light of the wavelength on the information recording plane of said one of said plurality of types of optical recording media, said wavelength being one of said first and second wavelengths corresponding to said one of said plurality of types of optical recording media;
- a light-path splitting element which splits the light path of the laser light of said first wavelength and the laser light of said second wavelength into separate light paths for the respective first and second wavelengths;
- a first detector which detects the reflected laser light of said first wavelength;
- and
- a second detector which detects the reflected laser light of said second wavelength,
- wherein either one of the laser light of said first wavelength and the laser light of said second wavelength is used for performing recording/reproducing of information on said one of said plurality of types of optical recording media, and, also, the other one is used for tilt detection for detecting the relative tilt between the information recording plane of said one of said plurality of types of optical recording media and an objective lens of said converging optical system.
An optical-pickup device which can record information on any one of a plurality of types of optical recording media, the thicknesses of the substrates of said plurality of types of optical recording media being different from each other, and wavelengths used for performing recording/reproducing on said plurality of types of optical recording media being different from each other, and can reproduce information recorded on said one of said plurality of types of optical recording media, said device comprising:
- a first semiconductor laser which emits laser light of a first wavelength;
- a wavelength-converting element which produces laser light of a second wavelength which is half of said first wavelength;
- a second semiconductor laser which emits laser light of a third wavelength which is different from said first wavelength and also is different from said second wavelength;
- a light-path synthesis element which causes the light path of the laser light of said third wavelength to become the same as the light path of the laser light of said first wavelength and the laser light of said second laser light;
- a converging optical system which can focus the laser light of the wavelength on an information recording plane of said one of said plurality of types of optical recording media, said wavelength being one of said first, second and third wavelengths corresponding to said one of said plurality of types of optical recording media;
- a detector which can detect at least any of the reflected laser light of said first wavelength, the reflected laser light of said second wavelength and the reflected laser light of said third wavelength,
- wherein any one of the laser light of said first wavelength, the laser light of said second wavelength and the laser light of said third wavelength is used for performing recording/reproducing of information on said one of said plurality of types of optical recording media, and, also, at least one of the other two of the laser light of said first wavelength, the laser light of said second wavelength and the laser light of said third wavelength is used for tilt detection for detecting a relative tilt between the information recording plane of said one of said plurality of types of optical recording media and an objective lens of said converging optical system.
An optical-pickup device which can record information on any one of a plurality of types of optical recording media, the thicknesses of the substrates of said plurality of types of optical recording media being different from each other, and wavelengths used for performing recording/reproducing on said plurality of types of optical recording media being different from each other, and can reproduce information recorded on said one of said plurality of types of optical recording media, said device comprising;
- a first semiconductor laser which emits laser light of a first wavelength;
- a wavelength-converting element which produces laser light of a second wavelength which is half of said first wavelength;
- a second semiconductor laser which emits laser light of a third wavelength which is different from said first wavelength and also is different from said second wavelength;
- a light-path synthesis element which causes the light path of the laser light of said third wavelength to become the same as the light path of the laser light of said first wavelength and the laser light of said second wavelength;
- a converging optical system which can focus the laser light of the wavelength on an information recording plane of said one of said plurality of types of optical recording media, said wavelength being one of said first and second wavelengths corresponding to said one of said plurality of types of optical recording media;
- a light-path splitting element which splits the light path of the laser light of said first wavelength, the laser light of said second wavelength and the laser light of said third wavelength into separate light paths for the respective first, second and third wavelengths;
- a first detector which detects the reflected laser light of said first wavelength;
- a second detector which detects the reflected laser light of said second wavelength;
- and
- a third detector which detects the reflected laser light of said third wavelength,
- wherein any one of the laser light of said first wavelength, the laser light of said second wavelength and the laser light of said third wavelength is used for performing recording/reproducing of information on said one of said plurality of types of optical recording media, and, also, at least one of the other two of the laser light of said first wavelength, the laser light of said second wavelength and the laser light of said third wavelength is used for tilt detection for detecting a relative tilt between the information recording plane of said one of said plurality of types of optical recording media and an objective lens of said converging optical system.
Dependencies are inferred from the claim text.