Abstract: To provide an optical component (phase plate) capable of acquiring an image of a deep depth of field or focal position, and an imaging device using it. What is provided is the optical component that includes multiple ring zones demarcated by multiple concentric circles, and is configured to be rotationally symmetric to a center of the concentric circles. Cross sections of the ring zones on a plane being parallel to a direction perpendicular to the concentric circles and including the center have concave or convex shapes. Each of the concave or convex shapes of the cross sections of the ring zones is asymmetric to a centerline of a width of each of the ring zones in a radial direction of the concentric circles.

Abstract: A phase filter 101 is configured to comprise an annular structure rotationally symmetrical about an optical axis, each annular zone including a cross-sectional shape of substantially parabola for uniformly extending incident rays of light on a focal plane and letting the rays overlap with each other.

Abstract: An imaging device includes an imaging element, a phase plate to modulate the optical transmission function of the optical image of the object, and an optical system for focusing the optical image modulated via the optical plate on the imaging surface of the imaging element, a spatial filter processing unit for image restoration processing to remove modulation by an optical phase filter by implementing two-dimensional spatial filtering processing on the image focused on the imaging surface of the imaging element. Modulation characteristics applied to the optical system by the phase plate are respectively different in the horizontal and vertical directions crossing at right angles along the flat surface of the imaging surface perpendicular to the optical axis.

Abstract: An object of the present application is to thin a thick lens used in an automobile headlamp optical system and a projector lighting optical system while maintaining the optical properties of the lens. A diffractive lens includes, on at least one surface, an optical surface with a plurality of areas defined by a plurality of steps. A blaze wavelength of the diffractive lens is within a wavelength spectral range of a light source used. An optical path difference between adjacent areas at the blaze wavelength is larger than a coherence length of the light source. The diffractive lens substantially acts as a Fresnel lens at a wavelength other than the blaze wavelength.

Abstract: An imaging device includes an imaging element, a phase plate to modulate the optical transmission function of the optical image of the object, and an optical system for focusing the optical image modulated via the optical plate on the imaging surface of the imaging element, a spatial filter processing unit for image restoration processing to remove modulation by an optical phase filter by implementing two-dimensional spatial filtering processing on the image focused on the imaging surface of the imaging element. Modulation characteristics applied to the optical system by the phase plate are respectively different in the horizontal and vertical directions crossing at right angles along the flat surface of the imaging surface perpendicular to the optical axis.

Abstract: A holographic recording medium in which information can be reproduced by phase conjugate beam without requiring a mirror for obtaining the phase conjugate beam and its driving part and recording density is not reduced. The recording medium includes a recording layer in which an interference pattern is recorded and a light absorption/transmission layer which can be reversibly changed to be in a first state where signal beam and reference beam passed through the recording layer are absorbed at the time of recording of information and a second state where the reference beam is transmitted at the time of reproduction of information, and the reference beam transmitted through the light absorption/transmission layer is reflected by a reflection layer to produce the phase conjugate beam.

Abstract: In an imaging camera system formed of a camera optical system that focuses an object to be imaged on an image sensor surface and a system that performs image processing on a detected image, a phase filter inserted in a position in the vicinity of an aperture of the optical system is characterized in that the phase filter has at least one surface having a non-rotationally symmetrical aspheric shape having three protrusion and three recesses within an effective diameter, one of the protrusions having a local maximum within the effective diameter, one of the recesses having a local minimum within the effective diameter, the remaining two protrusions and recesses continuously inclined toward a region outside the effective diameter.

Abstract: A monocular holographic storage device or system to provide for compact recording and/or reading of data pages in a holographic storage medium. Also provided are methods for carrying out such data storage and/or data recovery using a monocular holographic storage device or system. Further provided are articles comprising holographic storage media for recording or for reading recorded data using such devices or systems.

Abstract: There is a need to accurately lock focus of a laser beam onto a target data layer of a multilayer optical disc. The above need can be addressed by, for example, performing a focus lock operation after a spherical aberration correction amount is set in such a way as to make smaller the ratio of the focus error signal waveform amplitude at the data layer adjacent to a target data layer through which a laser beam passes earlier than through the target data layer to the focus error signal waveform amplitude at the target data layer than that when the spherical aberration correction amount is set so as to be optimal for the target data layer.

Abstract: A monocular holographic storage device or system to provide for compact recording and/or reading of data pages in a holographic storage medium. Also provided are methods for carrying out such data storage and/or data recovery using a monocular holographic storage device or system. Further provided are articles comprising holographic storage media for recording or for reading recorded data using such devices or systems.

Abstract: A monocular holographic storage device or system to provide for compact recording and/or reading of data pages in a holographic storage medium. Also provided are methods for carrying out such data storage and/or data recovery using a monocular holographic storage device or system. Further provided are articles including holographic storage media for recording or for reading recorded data using such devices or systems.

Abstract: A rewritable optical disk apparatus, optical information recording and reproducing apparatus or the like is allowed to automatically and properly adjust the optical system to the optimum focal condition regardless of the readout signal detector's positional error and the residual aberration in the optical system. The spherical aberration and defocus are coarsely adjusted using the amplitude (PP amplitude) of the tracking error signal and then finely adjusted using the amplitude (RF amplitude) of the readout signal. Since the spherical aberration can properly be adjusted, it is possible to raise the reliability of the readout signal.

Abstract: An interference type optical head and an optical disk device that can easily adjust an optical path length difference of a couple of lights, ensure higher signal amplification effect, and are suitable for reduction in size are provided in order to improve a regeneration signal quality with amplification of signal in the case where reflectivity of each layer must be lowered and relative noise for the signal increases because read speed is high in a multilayer optical disk. In view of essentially improving an S/N ratio of the regeneration signal in high-speed rotation of a multilayer disk, a plurality of interference phases are generated and an optical system for differential calculation has been reduced in size with an angular selective polarization conversion element in the optical disk device for amplifying the signal with interference of the light not radiated to the disk with the reflected light from the disk.

Abstract: An optical pickup device that can reduce interlayer crosstalk, without changing the configuration of the optical system, and without excessively increasing the size of the optical system. The optical pickup device reproduces a signal from a multilayered optical information recording medium having a plurality of information recording layers. The optical pickup device uses a collimating lens unit as a collimating optical system that collimates light from a light source, and the collimating lens unit includes a first and second lens group arranged at a predetermined distance from each other so as to form a converged light spot in the interior of the collimating lens unit, and an optical element provided between the first lens group and the second lens group so as to form a light spot at a position defocused from the position of the converged light spot, thereby decreasing quantity of light passing through the collimating lens unit.

Abstract: An optical pickup for recording a hologram by using an angle multiplexing method. An optical beam is separated into two beams, a signal beam and a reference beam having different convergence/divergence degrees, by using an optical component such as a diffraction lens. The signal and reference beams are made incident upon the same objective, and the optical component or the objective lens is moved in a direction perpendicular to an optical axis, to thereby realize angle multiplex recording. If an optical information recording medium is inclined, the optical component or the objective lens is moved along the direction along which the optical information recording medium moved to change an angle of the reference beam incident upon the optical information recording medium and compensate for degradation of a reproduction signal.

Abstract: A grating element is provided with diffraction members wherein protrusions and recesses are periodically arranged, respectively, on one surface of each of transparent substrates. The diffraction members are laminated in the substantially perpendicular direction to the transparent substrates, the protrusions of the diffraction members are made of a dielectric multilayer film, and the dielectric multilayer film has dielectric films of two or more types laminated in the substantially perpendicular direction on the transparent substrates. The wavelengths of laser beams diffracted at predetermined diffraction efficiencies by the diffraction members are different from one another.

Abstract: An optical disc apparatus includes a laser diode, a first optical component which branches beams from the laser diode into a first beam and a second beam, an objective lens which focuses the first beam on an optical information recording medium, an actuator which drives the objective lens in an optical axis direction, a reference mirror provided in an optical path of the second beam, an optical path length varying unit which varies an optical path length of the second beam, a first photo detector, a second photo detector, a second optical component which branches beams obtained by combining the first beam which is reflected by the optical information recording medium and the second beam which is reflected by the reference mirror and which makes the branched beams incident on the first and second photo detectors, and a signal processing part.

Abstract: A holographic recording medium in which information can be reproduced by phase conjugate beam without requiring a mirror for obtaining the phase conjugate beam and its driving part and recording density is not reduced. The recording medium includes a recording layer in which an interference pattern is recorded and a light absorption/transmission layer which can be reversibly changed to be in a first state where signal beam and reference beam passed through the recording layer are absorbed at the time of recording of information and a second state where the reference beam is transmitted at the time of reproduction of information, and the reference beam transmitted through the light absorption/transmission layer is reflected by a reflection layer to produce the phase conjugate beam.

Abstract: Provided is a recording and retrieval apparatus for a multi-layer optical disk. A multi-layer optical disk in which a plurality of recording layers and a single servo layer are combined to form a set is used. A spot for the servo layer and a spot for the recording layers are turned on in a time-sharing manner. Servo signal detection areas are formed discretely in the servo layer. The servo signal detection areas and data recording areas are provided so as not to overlap each other when viewed from the spot incident side. Thus, separation of data from each of the layers can be done by even a single photodetector without interference.

Abstract: A monocular holographic storage device or system to provide for compact recording and/or reading of data pages in a holographic storage medium. Also provided are methods for carrying out such data storage and/or data recovery using a monocular holographic storage device or system. Further provided are articles including holographic storage media for recording or for reading recorded data using such devices or systems.