Hitachi Media Electronics Co., Ltd.

Hitachi, Ltd.

Nichia Corporation

Hitachi-lg Data Storage, Inc.

Hitachi, Litd.

Shigeharu Kimura

Takeshi Shimano

Koichi Watanabe

Toshiteru Nakamura

Chusuke Munakata

Kimio Tatsuno

Tatsuro Ide

Hirohisa Sano

Masahide Tokuda

Nobuo Nakai

Shinobu Hase

Eriko Tatsu

Harukazu Miyamoto

Takao Watanabe

Takahiro Kurokawa

Akemi Hirotsune

Tomoto Kawamura

Kazuyoshi Yamazaki

Yoshitoshi Ito

Kunikazu Ohnishi

Masataka Shirai

Yoichi Tamaki

Kenji Maio

Manabu Shiozawa

Yuzo Taniguchi

Toshio Sugiyama

Hiroto Nagatomo

Tetsuo Ariyoshi

Takeshi Doi

Kyo Suda

Kanji Kinameri

Mikihito Saito

To measure homodyne interference with a CARS microscope, a supercontinuum beam is used as a light source. A supercontinuum beam is generated using a nonlinear optical fiber that has normal dispersion in which the coherence between pulses is maintained. As the phases of the interference components of detected beams are the same between pulses, it is possible to integrate the interference components and thus improve the signal-noise ratio.

Cars microscope

When a simple magnification optical system is used in reproduction of a recording medium in which a large number of minute modified regions are three-dimensionally formed inside solid matter, contrast is insufficient and interlayer crosstalk is increased, and therefore, it is impossible to take a sufficient S/N ratio. Provided is a recording medium in which at least one layer is configured by a set of two adjacent sub-layers, and dots on a sub-layer correspond to a recording data '1' and dots on the other sub-layer correspond to '0'. These data are played back.

Optical recording medium and optical information playback method

Provided is an optical apparatus characterized in that alight from a light source is split to a first light and a second light, and the first light is focused onto an observation object, that an optical filter having a light shielding region for high resolution is disposed in at least one optical path selected from optical paths of the first light, second light and response light from the observation object, that an interference light formed by causing interference between the response light and the reference light in polarized states different from each other is split to multiple beams, and desired amplitude information signals are obtained from the multiple beams through a phase plate and a polarization plate to increase intensity of the second light, whereby the signal to noise ratio is improved.

Optical apparatus

For an optical device as a transmission-type scanning optical microscope having a pinhole or a slit for limiting the amount of a detected light beam, a method of moving a scanning beam without moving an observation sample to be scanned is realized. A scanning beam from a beam scanning mechanism that has passed through an observation sample is focused onto a reflection plate, and is then returned back again to the observation sample. A light beam that has returned back from the sample is further fed back to the beam scanning mechanism, and then, the light beam that has been limited through a fixed pinhole or a slit is detected with a photodetector.

Optical device for transmission-type scanning by moving scanning beam without moving observation sample

A signal is amplified by making a CARS beam from an observed body and a reference beam which is a portion of a super continuum beam and has a frequency of &#x3c9;=2&#x3c9;&#x2212;&#x3c9;interfere with each other and taking out the signal from an interference beam of the CARS beam and the reference beam.

An optical system capable of obtaining a high-resolution image using interference and thus capable of providing a stable signal is realized. A particular polarization state of response light emitted from an object is selected, and light in the selected particular polarization state is split into two beams. The split two beams are polarized into two different polarization states. After one of the two beams is subjected to an image inversion, the two beams are condensed such that they interfere with each other. The interfering light is split into a plurality of beams, and each of these beams is detected after they are passed through different polarizing filters. Detected signals are combined together and processed to obtain high-stability amplitude information without being influenced by a phase difference between the two beams.

An optical pickup includes a light source, an optical system for irradiating a recording medium including a plurality of recording layers with light from the light source, a diffraction optical element that divides light reflected from the recording medium into a plurality of optical fluxes and diffracts the fluxes, and an optical detector receiving the optical flux diffracted by the diffraction optical element. The optical detector includes a light receiving element detecting a focus error signal, wherein a longitudinal direction of the light receiving element is arranged to coincide with a circumferential direction of the recording medium, or arranged to be inclined to a circumferential or radial direction.

Optical pickup and optical information recording and reproducing apparatus

A tracking signal and a focusing signal are stabilized by eliminating multi-layer crosstalk. The diffraction position, with respect to a semiconductor detector, from a center region of a multi-region diffraction grating disposed along the return path of reflection light from the layer of interest is placed further away from the optical axis than the diffraction position from a peripheral part of the diffraction grating. Stray light from other layers is thus prevented from being incident on a sensing region for a peripheral region of the diffraction grating. Further, the area of the semiconductor detector is reduced by dividing the center region.

Optical pickup device with detection optical system

In a multilayer optical recording medium having at least three recording layers, an influence of interlayer crosstalk due to unnecessary light is suppressed. Each of the recording layers includes an information recording area, and the recording layers other than the nearest recording layer and the farthest recording layer when viewed from a light incident side include a first annular area having uneven patterns formed thereon, and a second annular area having uneven patterns formed thereon, the first annular area being adjacent to an inner side of the information recording area, the second annular area being adjacent to an outer side of the information recording area.

Multilayer optical recording medium having three or more recording layers with reduced interlayer crosstalk

According to the present invention, of all beams of light reflected from the optical disc, only light in a peripheral region excluding a push-pull region is used to generate a DPD signal. In this method of signal generation that optimizes internal light-receiving surface interconnections in a photodetector, the lens error signal required for the generation of a tracking error signal in the DPP scheme is amplified at a lower amplification factor. In addition, the light reflected from the multilayered optical disc will be divided into a plurality of regions and the divided beam of light will be focused at different positions on the photodetector. When the beam is focused upon a desired layer, stray light from recording layers other than those to be subjected to information reproduction will not enter the photodetector light-receiving surfaces used for servo signals.

Optical pickup device and optical disc apparatus using same

Of the beams reflected by an optical disk, only peripheral beams excluding the push-pull region are used to generate a DPD signal in order to optimize internal wire connections among the light receiving areas of the optical detector and thereby reduce the amplification factor of the lens error signal, required for generating the tracking error signal of the DPP method. A beam reflected from a multilayered optical disk is divided into some beam diffraction areas. The divided beam diffraction areas and the light receiving areas are so arranged that the divided beams focus at different positions on the optical detector and that, when a beam is focused on a target recording layer of the disk, stray light from other than the target recording layer being reproduced does not enter into the servo signal light receiving area of the optical detector.

Optical pickup device and optical disk device using the same

An optical pickup device capable of eliminating interlayer crosstalk which is responsible for fluctuation in control signals and error rate in data signals, thereby ensuring stable action for a multilayered recording disc with a narrow interlayer spacing. The reflected beam coming from the multilayered disc is divided along the central line into two parallel portions by the dividing optical system and then condensed. The reflected beam coming from the active layer, which has been condensed, is reflected by the reflecting plane whose reflecting region is limited and the thus reflected beam is detected by the optical detector. The reflected beam coming from other layers is not reflected by the reflecting plane, so that interlayer crosstalk is reduced.

Optical pickup device

An optical pickup apparatus for use on multi-layered optical information storage medium in which influences of reflected light, which result in crosstalk from adjacent layers in a multi-layered optical disk, are mitigated. In an astigmatic optical system of the optical pickup, a first composite segmented wave plate having a segmentation direction that is in the same direction as the focal line that is close to the astigmatic optical system, a second composite segmented wave plate of the same segmentation direction, and an analyzer are inserted.

Optical pickup apparatus for use on a multi-layered optical information storage medium

An optical pick-up which permits the relative position of a diffracting optical element and a photodetector to be adjusted by feedback control with signals which are generated when more than one kind of diffracted light differing in order is received, the diffracted light occurring as the reflected light from the optical disc is divided and diffracted by the diffracting optical element having multiple regions. The photodetector which detects the light beam passing through the central region of the diffracting optical element and generates RF signals is juxtaposed with sub-photodetectors, so that they receive reflected stray light from out-of-focus layers and perform computation to calculate the reflected stray light component which the RF signal detector receives, thereby detecting only the component of signals of the reflected light from a target layer.

Optical pick-up and optical information recording and reproducing apparatus

Provided is an optical pickup device capable of stabilizing a tracking signal and a focusing signal and of preventing quality deterioration of a data signal by eliminating a multi-layer crosstalk. Of reflected lights from a multi-layer disc, a reflected light from a target layer is split into two by a light flux splitting optical system so that the reflected light is spread out toward two directions with respect to a central line, and then the split lights are condensed. In this case, a reflected light from another layer does not reach a condensing position of the reflected light from the target layer, and only the reflected light from the target layer can be detected by a detector. Accordingly, a crosstalk from the another layer is eliminated.

Growing community of inventors

Yokohama, Japan

Shigeharu Kimura