Abstract: In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

Abstract: A first protection circuit includes a first diode and a first transistor. The anode of the first diode is connected to a terminal to be protected. The first transistor is configured as an N-channel MOSFET, and arranged such that the first terminal of the conduction channel thereof is connected to the cathode of the first diode, and the second terminal of the conduction channel thereof, and the gate and the back gate thereof are connected to a fixed voltage terminal. The first transistor is configured as a floating MOSFET formed within an N-type well formed in a P-type semiconductor substrate. The first diode is formed in the shared N-type well in which the first transistor is formed. The cathode of the first diode and the first terminal of the conduction channel of the first transistor are connected to the N-type well.

Abstract: An optical pickup device includes a laser light source 201, a collimating optical system 202 for converting laser light to parallel light, a focusing optical system 205 for focusing the parallel light onto an optical disc, a light detection unit for receiving returning light returning by reflection of the focused light from the optical disc 101 and outputting a detection signal, and a reflecting mirror 204 disposed between the collimating optical system and the focusing optical system. The reflecting mirror 204 has a reflective surface including three regions having different reflectances. The central region on the reflecting surface meets the other two regions, at positions illuminated by the light focused by the light focusing optical system, in boundary lines that are parallel to a radial direction on the optical disc 101. The reflectance of the central region is lower than the reflectances of the other two regions.

Abstract: An optical pickup device moves in a feed direction parallel to a radial direction of an optical disc rotating on an axis of rotation, and records or reproduces information on an information recording surface of the optical disc. The optical pickup device has a first light source that emits light of a first wavelength, a second light source that emits light of a second wavelength differing from the first wavelength, a first objective lens for focusing the light from the first light source onto the information recording surface, and a second objective lens for focusing the light from the second light source onto the information recording surface. The first and second objective lenses and the first light source are disposed in a plane that passes through the axis of rotation and is parallel to the feed direction.

Abstract: An optical head device and an optical disc apparatus of a simple structure capable of canceling an offset in a tracking error signal caused when an objective lens shifts; in the optical head device, a polarizing hologram 104 has first diffraction areas 112 and 113 including a whole of an area irradiated with overlap of a zeroth-order beam of reflection light from an optical disc 1 and positive/negative first-order beams of the reflection light, and a second diffraction area 111 including an area irradiated with the zeroth-order beam of the reflection light and not irradiated with the positive/negative first-order beams of the reflection light without including the first diffraction area; and a photodetector 109 has a first light receiving section 131 for receiving a first light beam which is a zeroth-order beam of diffraction light generated by the polarizing hologram 104, a second light receiving section for receiving a second light beam which is a positive first-order beam of the diffraction light generated

Abstract: An optical head device mounted in an optical disc device. The optical head device is provided with a diffractive optical element and a photodetector. The diffractive optical element has: a primary diffraction region at a location on which the positive and negative first-order components and some of the zero-order component of a reflectively diffracted light beam are incident; and secondary diffraction regions at locations on which the rest of the zero-order component but none of the positive or negative first-order components of the reflectively diffracted light beam are incident. A main light-receiving section of the photodetector receives the zero-order component of a transmissively diffracted light beam that has passed through the primary diffraction region and the secondary diffraction regions.

Abstract: The three-dimensional image display apparatus includes a display unit having display pixels arranged in rows and columns, and configured to display right-eye images and left-eye images alternately at every other column. Lenticular lenses with positive refractive power are provided corresponding to respective columns of the display pixels. The lenticular lenses and the columns of the display pixels are the same in number. The lenticular lenses collimate light representing the right-eye images and light representing the left-eye images. A deflection optical element deflects the collimated light representing the right-eye images and the collimated light representing the left-eye images toward right-eye and left-eye three-dimensional viewing areas. The deflection optical element includes a plurality of planes extending in a direction of the columns of the display pixels and inclined relative to a normal line of the display unit. The planes and the columns of the display pixels are the same in number.

Abstract: An optical disc device compatible with optical discs of different types having different track pitches, having a light detecting means (104) disposed in the path of diffracted light from the recording tracks on the optical disc (101), on which a light beam from a light emitting section (103) is incident. During the loading of the optical disc, the optical disc device discriminates the type of optical disc from the detection output of the light detecting means (104) and the positional relation between the optical disc (101) and the light detecting means (104). A simple structure thus enables the optical disc type to be discriminated.

Abstract: In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

Abstract: An optical disc discriminating method and an optical disc discriminating apparatus which can discriminate a type of optical disc with a simple configuration, causes a drive means to vary an incident angle of a laser light beam with respect to an optical disc while irradiating the optical disc with the laser light beam from a light beam generating section, causes a photodetector to detect a diffraction light of the laser light beam from a recording track of the optical disc, detects a value corresponding to the incident angle when the diffraction light is detected, and discriminates the type of the optical disc on the basis of the detected value.

Abstract: In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

Abstract: In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

Abstract: In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

Abstract: An optical pickup device includes a plurality of laser light sources emitting laser beams of different oscillation wavelengths, and a plurality of objective lenses on which the laser beams in the form of diverging beams emitted by the plurality of laser light sources are incident, and which directly focus the laser beams onto a recording surface of an optical disc. A rising mirror reflects a laser beam in the form of a diverging beam emitted by a laser light source of a predetermined oscillation wavelength among the plurality of laser light sources so as to lead the laser beam to one of the plurality of objective lenses, and transmits the laser beam in the form of a diverging beam emitted by the other laser light source. As the rising mirror transmits the laser beam in the form of the diverging beam emitted by said other laser light source, astigmatism is generated so as to correct existing astigmatism of the laser beam emitted by said other laser light source.

Abstract: An optical head device mounted in an optical disc device. The optical head device is provided with a diffractive optical element and a photodetector. The diffractive optical element has: a primary diffraction region at a location on which the positive and negative first-order components and some of the zero-order component of a reflectively diffracted light beam are incident; and secondary diffraction regions at locations on which the rest of the zero-order component but none of the positive or negative first-order components of the reflectively diffracted light beam are incident. A main light-receiving section of the photodetector receives the zero-order component of a transmissively diffracted light beam that has passed through the primary diffraction region and the secondary diffraction regions.

Abstract: An analog signal is input to an input terminal. An analog signal is output via an output terminal. A first transistor is an N-channel MOSFET, and is provided between the input terminal and the output terminal. A first resistor is provided between the gate of the first transistor and a first fixed voltage terminal (power supply terminal), which sets the gate of the first transistor to a high-impedance state.

Abstract: An optical pickup with a simplified structure in which, according to the type of optical disc, diffracted light from three types of laser light can be directed efficiently onto a photodetector and appropriate focus control can be performed based on the signals detected by the photodetector, and a diffractive optical element that can be used in the optical pickup, which has a semiconductor laser 10 that can emit three types of laser light, a diffractive optical element 42 that diffracts the laser light reflected from the optical disc 31, and a single photodetector 43 that detects the diffracted light exiting the diffractive optical element 42.

Abstract: An analog signal is input to an input terminal. An analog signal is output via an output terminal. A first transistor is an N-channel MOSFET, and is provided between the input terminal and the output terminal. A first resistor is provided between the gate of the first transistor and a first fixed voltage terminal (power supply terminal), which sets the gate of the first transistor to a high-impedance state.

Abstract: A control circuit 10 according to the present invention transits to a first current limiter mode when an output current of a DC-DC converter circuit reaches an upper limit current or greater in a normal mode; transits to the normal mode when the output current falls below the upper limit current in the first current limiter mode; transits to a second current limiter mode when a first predetermined period elapses without a transition to the normal mode in the first current limiter mode; and transits to the normal mode when a second predetermined period elapses in the second current limiter mode.

Abstract: An optical disc device compatible with optical discs of different types having different track pitches, having a light detecting means (104) disposed in the path of diffracted light from the recording tracks on the optical disc (101), on which a light beam from a light emitting section (103) is incident. During the loading of the optical disc, the optical disc device discriminates the type of optical disc from the detection output of the light detecting means (104) and the positional relation between the optical disc (101) and the light detecting means (104). A simple structure thus enables the optical disc type to be discriminated.