Abstract: An optical medium reproducing apparatus that optically reproduces an optical medium on which a plurality of tracks is formed in which a beam returning from the optical medium is divided into a first region of an outside portion and a second region of an inside region, according to the shape of the pupil of an object lens, and crosstalk between the tracks is reduced by using a first detection signal of the first region and a second detection signal of the second region.

Abstract: An information reproducing apparatus has a medium with a linear tracking mark extending in a scanning direction and a linear data mark extending in a direction orthogonal to the scanning direction. A light control unit irradiates the data mark with a first near-field light polarized in the scanning direction and irradiates the tracking mark with a second near-field light polarized in the direction orthogonal to the scanning direction. A detector detects light scattered by the data mark and the tracking mark irradiated with the first near-field light and the second near-field light, respectively. A signal processing unit processes a first output signal from the detector corresponding to the detected light scattered by the data mark and processes a second output signal from the detector corresponding to the detected light scattered by the tracking mark.

Abstract: An optical-pickup apparatus includes: a single-wavelength-laser diode to emit a first-laser beam; a two-wavelength-laser diode to emit second- and third-laser beams; an objective lens; a photodetector to be irradiated with first- to third-reflected-light beams of the first- to third-laser beams reflected from the signal-recording layers of first- to third-optical discs; an aberration-correcting plate to guide the second- and third-laser beams toward the lens, and correct astigmatism of the reflected-light beams, and guide the astigmatism-corrected-reflected-light beams toward the photodetector; a semitransparent mirror to guide, toward the lens, the first-laser beam and the second- and third-laser beams having been guided by the aberration-correcting plate, and guide the reflected-light beams toward the aberration-correcting plate; a quarter-wave plate to convert the first- to third-laser beams from linearly-polarized light into circularly-polarized light, and convert the reflected-light beams from circularly

Abstract: In a beam applying method, recording and reproducing operations are performed on an optical recording medium, in which a signal is recorded and reproduced by applying a beam thereto and which has a recording layer on which the signal is recorded, a quarter-wavelength plate formed below the recording layer, a polarizing plate formed further below the quarter-wavelength plate, and a reflecting film formed below the quarter-wavelength plate. The beam applying method includes the steps of; emitting a beam to be applied to the optical recording medium; and driving a quarter-wavelength plate inserted into an optical system serving to guide the emitted beam to the optical recording medium so that the optical axis direction thereof has a predetermined angle difference at the time of performing a recording operation and reproduction.

Abstract: The present invention provides a plasmonic optical transformer to produce a highly focuses optical beam spot, where the transformer includes a first metal layer, a dielectric layer formed on the first metal layer, and a second metal layer formed on the dielectric layer, where the first metal layer, the dielectric layer, and the second layer are patterned to a shape including a first section having a first cross section, a second section following the first section having a cross-section tapering from the first section to a smaller cross-section, and a third section following the second section having a cross-section matching the tapered smaller cross-section of the second section,

Abstract: An object of the present invention is to provide an extraction optical system capable of separating and extracting a signal light and a stray light with a simple configuration, and an optical head device including the same. A phase plate and a phase plate are +?/4 phase plates, while a phase plate and a phase plate are ??/4 phase plates. A focal line, a focal line and a focal line represent a focal line of a stray light, a focal line of a reproduction light and a focal line of a stray light, respectively. All beams of the reproduction light enter the state in which a polarization direction is rotated by 90 degrees after passing through the phase element. In contrast to the all light bundles of the reproduction light, polarization directions of all light bundles of the stray lights and are not rotated even after passing through the phase element.

Abstract: An optical element includes: opposing surfaces each including two areas each of which includes a fine-periodic structure. The fine-periodic structures of the two areas have different directions from each other in each of the opposing surfaces. One of the opposing surfaces with the fine-periodic structures works as a quarter-wave plate and the other of the opposing surfaces with the fine-periodic structures works as a polarization separating element. A boundary of the two areas in one of the opposing surfaces and a boundary of the two areas in the other of the opposing surfaces are positionally identical.

Abstract: An optical pickup includes: a light source; an objective lens; a beam splitter; a quarter wave plate that transforms the optical beam into a circularly polarized optical beam and also transforms the circularly polarized reflection optical beam into an optical beam whose polarization direction is perpendicular to the optical beam; a light detector; a neutral density filter section placed on a mutual optical path of those beams, reducing the intensity of the optical beam while maintaining the intensity of the reflection optical beam; and a filter drive section that puts the neutral density filter section in the mutual optical path or outside of it, wherein the intensity of the optical beam and the filter drive section are controlled such that the amount of the optical beam emitted to the optical disc is maintained at a predetermined level.

Abstract: An optical pickup unit includes a light source emitting a light beam, an objective lens focusing the light beam onto an information recording medium, a light detection part receiving the light beam reflected from the information recording medium, and a light blocking part selectively blocking a part of the light beam with respect to a radial direction. The light blocking part is provided in an optical path of the light beam centered on an optical axis.

Abstract: A phase plate and an optical head device are provided, which are capable of suppressing changes of the amount of light incident on a light-receiving unit even if the phase difference caused by transmission through a protective layer of an optical recording medium differs depending on the type of optical recording medium. The phase plate includes a birefringent medium and produces a phase difference in linearly polarized light incident on the phase plate between a polarization component having a polarization direction parallel to the optic axis of the birefringent medium and a polarization component having a polarization direction perpendicular to the optic axis.

Abstract: The present invention discloses an optical system for extracting signal light components from a beam including the signal light components and stray light components. The optical system includes a condensing optical element situated on an optical path of the beam for condensing the beam, a polarization changing unit for changing the state of polarization of at least one of the signal light components and the stray light components included in the incident beam transmitted through the condensing optical element, and an extracting element for extracting the signal light components included in the beam transmitted through the polarization changing unit.

Abstract: 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.

Abstract: A compatible optical pick-up apparatus, which records to and/or reproduce from both digital versatile disc (DVD)-type optical disks and compact disc (CD)-type optical disks for improving a signal regeneration capacity and a tracking capacity in operation at a high temperature. A polarized hologram of the optical pick-up apparatus is divided into six diffraction regions. The rays of a first light diffracted at the first and second diffraction regions are separately received by divided parts of a first bisected light-receiving portion of a photodetector.

Abstract: An optical scanning device for scanning of a first, second and third type of optical record carrier with radiation of a first wavelength ?1, a second wavelength ?2 and a third wavelength ?3, respectively, where the three wavelengths are substantially different. The device comprises: a radiation source for emitting a beam of said radiation, an objective system for converging the beam on a selected one of the optical record carriers, and a phase structure arranged in the path of the beam, the phase structure comprising a plurality of phase elements of different heights, forming a non-periodic stepped profile of optical paths in the beam, and is characterised in that the stepped profile substantially approximates a flat wavefront at the first wavelength ?1, a spherical aberration wavefront at the second wavelength ?2, and a flat or spherical aberration wavefront at the third wavelength ?3.

Abstract: An optical pick-up device includes a light source (2), a polarized light beam converter (4), a splitter (6), a collimating lens (7), and a photo-detector (9). A linear polarized light beam with a first type of polarized component and a second type of polarized component is emitted from the light source, and passes through the polarized light beam converter. The first type of polarized component is converted into the second type of polarized component by the polarized light beam converter. Then part of the light beam with the second type of polarized component passes through the splitter and is focused onto an optical disc (8) by the collimating lens. The optical disc reflects the light beam that contains recorded information read from the optical disc. The reflected light beam passes back through the collimating lens, is reflected by the splitter, and is received by the photo-detector.

Abstract: An optical head for recording or reproducing a signal with respect to an optical recording medium, which includes an optical element disposed between a light source and an optical recording medium. The optical element has an optically active polymer film in which an optical rotation property changes with respect to an applied voltage, a pair of conductive transparent thin films for applying a voltage to the optically active polymer film, and a transmittance polarization anisotropic part having a different transmittance with respect to a polarization direction, which is disposed on one of the conductive transparent thin films. By changing the applied voltage to the optically active polymer film, a light quantity of a linearly polarized light transmitted through the optical element can be changed substantially instantaneously. Therefore, the power of light reaching the optical recording medium can be switched substantially instantaneously at the time when switched between recording and reproduction.

Abstract: To implement light quantity monitoring with high frequency responsivity and correction of astigmatic differences of a semiconductor laser with a simple configuration with a fewer parts. Of the light beam output from a semiconductor laser light source 101, a peripheral beam component is entered by a light reflection element 107 into an anterior light monitoring photodetector 103 formed in the vicinity of a semiconductor laser light source 101. Furthermore, the surface of the reflection sphere of the light reflection element is formed anamorphic, and thus condensed to an appropriate size on the photodetector without being focused, providing high frequency responsivity. Furthermore, the light reflection element 107 is placed inclined at a predetermined angle so as to cancel out astigmatic difference of the optical semiconductor laser light source 101.

Abstract: An optical pickup is provided which includes a light source, an optical system for converging a laser beam emitted from the light source, and an optical element having a function of increasing a numerical aperture of the optical system, wherein recording and/or reproducing information on a recording medium is performed by using the laser beam from the light source while the optical element is brought in contact with or in close to the recording medium, and the optical element has a contamination-preventing structure.

Abstract: To implement light quantity monitoring with high frequency responsivity and correction of astigmatic differences of a semiconductor laser with a simple configuration with fewer parts. Of the output from a semiconductor laser light source, a peripheral component is entered by a light reflection element into an anterior light monitoring photodetector formed in the vicinity of a semiconductor laser light source. Furthermore, the surface of the reflection sphere of the light reflection element is anamorphic, and thus condensed to an appropriate size on the photodetector without being focused, providing high frequency responsivity. Furthermore, the light reflection element is inclined at a predetermined angle to cancel out astigmatic differences of the optical semiconductor laser light source. In addition, the photodetector is placed so that reflected light is bent by an inclination of the light reflection element, reducing the amount of parallel displacement during adjustment of the light reflection element.

Abstract: Beam shaping means may have a shaping ratio set to allow a light beam emitted from a semiconductor laser and having an elliptic intensity distribution to have an ellipticity of no more than two to obtain a spot achieving high light availability and reduced in size. Furthermore, the shaping ratio can be set to no more than 2.5 to allow a polalized-beam splitter (light separation means) and other components to be arranged in a converged flux passing between the semiconductor laser and a collimator lens.

Abstract: An optical head includes a light source for generating a luminous flux, a polarization beam splitter, an object lens opposed to an appropriate recording medium, and a power monitoring device for monitoring the power of the luminous flux output from the light source. The power monitoring device is adapted to utilize a peripheral portion of the luminous flux. This peripheral portion of the luminous flux is distinct from the portion of the luminous flux that is used for reproducing predetermined information from the recording medium and recording the predetermined information onto the recording medium.

Abstract: An optical head for recording or reproducing a signal with respect to an optical recording medium, which includes an optical element disposed between a light source and an optical recording medium. The optical element has an optically active polymer film in which an optical rotation property changes with respect to an applied voltage, a pair of conductive transparent thin films for applying a voltage to the optically active polymer film, and a transmittance polarization anisotropic part having a different transmittance with respect to a polarization direction, which is disposed on one of the conductive transparent thin films. By changing the applied voltage to the optically active polymer film, a light quantity of a linearly polarized light transmitted through the optical element can be changed substantially instantaneously. Therefore, the power of light reaching the optical recording medium can be switched substantially instantaneously at the time when switched between recording and reproduction.

Abstract: An optical pickup apparatus that is capable of eliminating a crosstalk component effectively. In the apparatus, a sub-beam for eliminating a crosstalk component is produced by utilizing a polarizing phase plate. The polarizing phase plate is provided with at least two phase zones with a different phase at each side on a basis of the center thereof. According to the apparatus, a position of the sub-beam is easily controlled in accordance with a track pitch of the optical disc by utilizing the polarizing phase plate consisting of a plurality of phase zones, thereby eliminating a crosstalk component optimally.