摘要:
An optical disk compliant with both a conventional optical disk such as a BD, HD DVD, and the like and a next-generation high-density optical disk according to a near-field light recording system and the like is provided.An information recording medium includes a first information recording layer and a second information recording layer, to/from which information is recorded or reproduced using laser beam. The first information recording layer is formed at a laser beam entrance surface, and is configured so that information can be recorded thereupon and/or reproduced therefrom using a first objective lens having a first numerical aperture NA1 and laser beam of a first wavelength λ1. The second information recording layer is formed so as to have a distance to the laser beam entrance surface is 0.05 mm to 1.2 mm and is configured so that information can be recorded thereupon and/or reproduced therefrom using a second objective lens having a second numerical aperture NA2 and laser beam of a second wavelength λ2. When a diffraction limit δ2, determined by the numerical aperture NA2 and the second wavelength λ2, is taken as δ2=0.61×λ2/NA2, a track pitch Tp1 of a track formed on the first information recording layer is Tp1
摘要:
An optical head is provided with a light source for emitting a first laser beam having a first wavelength shorter than 430 nm, a two-wavelength light source for emitting a second laser beam having a second wavelength equal to or longer than 430 nm, a flat beam splitter in the form of a single plate for reflecting the first laser beam emitted from the light source, a wedge prism in the form of a single plate for reflecting the first laser beam reflected by the flat beam splitter and transmitting the second laser beam emitted from the two-wavelength light source, and an objective lens for focusing the first laser beam reflected by the wedge prism on an information recording surface of a BD. The light source is arranged such that the optical axis of the first laser beam emitted from the light source is inclined with respect to that of the second laser beam emitted from the two-wavelength light source. By this construction, the miniaturization of the optical head can be realized.
摘要:
An optical disk compliant with both a conventional optical disk such as a BD, HD DVD, and the like and a next-generation high-density optical disk according to a near-field light recording system and the like is provided.An information recording medium includes a first information recording layer and a second information recording layer, to/from which information is recorded or reproduced using laser beam. The first information recording layer is formed at a laser beam entrance surface, and is configured so that information can be recorded thereupon and/or reproduced therefrom using a first objective lens having a first numerical aperture NA1 and laser beam of a first wavelength λ1. The second information recording layer is formed so as to have a distance to the laser beam entrance surface is 0.05 mm to 1.2 mm and is configured so that information can be recorded thereupon and/or reproduced therefrom using a second objective lens having a second numerical aperture NA2 and laser beam of a second wavelength λ2. When a diffraction limit δ2, determined by the numerical aperture NA2 and the second wavelength λ2, is taken as δ2=0.61×λ2/NA2, a track pitch Tp1 of a track formed on the first information recording layer is Tp1
摘要:
In the present invention, at the time of pulling a focus on an information recording surface of a disc, a focus servo is first pulled in a substrate surface of the disc, and with the servo in a settled state, a driving signal necessary for following surface wobble is stored, and a focus is pulled in the information recording surface of the disc based upon a signal superimposed with the driving signal and a focus search driving signal.
摘要:
When performing a read or write operation on an optical disc with information storage layers, this compatible optical head with a two-focus lens can reduce interference caused by an unnecessary diffracted light reflected from a non-target layer and not contributing to reading or writing. The head reads and/or writes information from/on storage media, including first and second media with different protective substrate thicknesses, by irradiating a given one with a laser beam and includes: a diffraction element that diffracts the beam to produce diffracted light of multiple orders; an objective lens for converging nth and mth order ones of the light on the respective storage layers of the first and second media; a photodetector that receives the beam reflected from the medium and condensed; and a light shielding portion for preventing a portion of the beam reflected from the storage layer of the second medium and including its optical axis from reaching the photodetector. The light shielding portion is arranged so as to reduce loss to be caused by cutting off the portion of the beam to a predetermined value or less.
摘要:
An optical disc type is determined by detecting focus error signals and an amount of returned light, while (i) emitting light having a wavelength maximizing a focal length and (ii) moving an objective lens in a direction of an optical axis. If an S shape and AS immediately after a surface are greater than those at the surface, the optical disc is determined to have a largest capacity. It is also determined whether there is a reflective layer at a depth equal or less than 0.1 mm, if not, then it is determined whether there is a reflective layer at a depth of 0.6 mm. If there is a reflective layer at the depth of 0.6 mm, then the type of the reflective layer is determined based on TE/RF signals, using blue light. If the blue light is not adaptable, red light is emitted to replay at a depth of 0.6 mm.
摘要:
An optical disk driving apparatus includes an optical head device having a laser light source, a converging optical system converging a light beam emitted by the laser light source onto an optical disk, a photo detector receiving reflected light reflected by the optical disk, and an aberration correcting optical system controlling aberration of the converging optical system; a motor rotating the optical disk; and a control section receiving a signal from the photo detector, wherein the converging optical system has an objective lens formed using resin as a main material, the aberration correcting optical system has a spherical aberration correcting element correcting spherical aberration, and the control section evaluates quality of a reproduction signal for information in the optical disk by using the reflected light received by the photo detector, and utilizes a result of the evaluation to perform closed loop control on the spherical aberration correcting element.
摘要:
An optical disk driving apparatus includes an optical head device having a laser light source, a converging optical system converging a light beam emitted by the laser light source onto an optical disk, a photo detector receiving reflected light reflected by the optical disk, and an aberration correcting optical system controlling aberration of the converging optical system; a motor rotating the optical disk; and a control section receiving a signal from the photo detector, wherein the converging optical system has an objective lens formed using resin as a main material, the aberration correcting optical system has a spherical aberration correcting element correcting spherical aberration, and the control section evaluates quality of a reproduction signal for information in the optical disk by using the reflected light received by the photo detector, and utilizes a result of the evaluation to perform closed loop control on the spherical aberration correcting element.
摘要:
An optical head is provided with a light source for emitting a first laser beam having a first wavelength shorter than 430 nm, a two-wavelength light source for emitting a second laser beam having a second wavelength equal to or longer than 430 nm, a flat beam splitter in the form of a single plate for reflecting the first laser beam emitted from the light source, a wedge prism in the form of a single plate for reflecting the first laser beam reflected by the flat beam splitter and transmitting the second laser beam emitted from the two-wavelength light source, and an objective lens for focusing the first laser beam reflected by the wedge prism on an information recording surface of a BD. The light source is arranged such that the optical axis of the first laser beam emitted from the light source is inclined with respect to that of the second laser beam emitted from the two-wavelength light source. By this construction, the miniaturization of the optical head can be realized.
摘要:
The type of a disc is determined by detecting focus error signals and the amount of returned light while emitting light with a wavelength such as infrared light which maximizes the focal length and moving an objective lens in the direction of an optical axis. If the S shape and AS immediately after the surface are greater than those at the surface, the optical disc is determined to be an optical disc with a largest capacity. It is determined whether or not there is a reflective layer at a depth equal to or less than 0.1 mm. If there is no reflective layer thereat, it is determined whether or not there is a reflective layer at a depth of 0.6 mm. If there is a reflective layer thereat, the type of the reflective layer is determined based on TE and RF signals with blue light. If the blue light is not adaptable to the layer, red light is emitted, and replay of the recording layer at a depth of 0.6 mm is performed.