Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Panasonic Intellectual Property Management Co., Ltd.

Kazuo Momoo

Seiji Nishiwaki

Yuichi Takahashi

Junichi Asada

Hiroaki Matsumiya

Junji Nagaoka

Kenji Nagashima

Youichi Saitoh

Hiroshi Kayama

Jun-ichi Asada

Tetsuo Saimi

Yohichi Saitoh

Hiroshi Yamamoto

Yasushi Kobayashi

Shoji Goto

Yuuichi Takahashi

Makoto Kato

Kousei Sano

Hideki Hayashi

Ichiro Kawamura

Yusuke Kanda

Tomoaki Tojo

Noritaka Akagi

Koichi Muramatsu

Goro Naoki

Yukio Hibino

Yoichi Saito

Akihiro Sakata

Noboru Itoh

Fumitake Sakai

Jun-iti Asada

Kenji Otani

Kei Ikeda

Shoji Gotoh

An optical information processing device writes and reads information on an information recording medium having recording layers. The optical information processing device includes: first and second light sources; a light condensing element that condenses light from the first and second light sources on the medium; a first photodetector that receives light reflected by the medium after being emitted from the first light source and generates a first focusing error signal; a second photodetector that receives light reflected by the medium after being emitted from the second light source and generates a second focusing error signal; and a focusing control circuit that controls the light condensing element by using the first focusing error signal in such a manner that the light from the second light source is condensed on each of the recording layers. The second focusing error signal is used to add a correction to the focusing control circuit.

Optical information processing device

A record playback apparatus of the present disclosure includes a plurality of optical pickups that records information on a recording medium or plays back information from the recording medium; a single transport mechanism that transports the plurality of optical pickups together; and a transport control circuit that drives the single transport mechanism so that, when the single transport mechanism is driven to transport the plurality of optical pickups to respective target positions on the recording medium, absolute value of a maximum value of transport errors of the plurality of optical pickups with respect to the respective target positions becomes substantially equal to absolute value of a minimum value of transport errors of the plurality of optical pickups with respect to the respective target positions.

Record playback apparatus

The first, third, fourth, and seventh photosensors are disposed on one side with respect to the centerline, and the second, fifth, sixth, and eighth photosensors are disposed on another side with respect to the centerline. The first and seventh photosensors are positioned between the third and fourth photosensors in the direction parallel to the centerline. The second and eighth photosensors are positioned between the fifth and sixth photosensors in the direction parallel to the centerline. The first photosensor receives overlapped light of the 0th-order light with the +1st-order diffracted light, the second photosensor receives overlapped light of the 0th-order light with the &#x2212;1st-order diffracted light, each of the third to sixth photosensors receives the 0th-order light, and does not receive the +1st-order diffracted light and the &#x2212;1st-order diffracted light, and each of the seventh and eighth photosensors receives at least the 0th-order light.

Recorder and player apparatus stably keeping track of recording medium

The recording and reproducing apparatus according to the present disclosure includes: a light source; an optical system configured to divide a beam from the light source, and to form a first optical spot and a second optical spot on a recording medium; a recording circuit configured to drive the light source and to modulate a light amount of the light source, and further to record the information on the recording medium by the first optical spot by modulating the light amount of the light source based on information; and an evaluation circuit configured to evaluate the information recorded on the recording medium by reproducing by the second optical spot in a period in which the recording circuit causes the light source to emit the beam at a constant light amount.

Recording and reproducing apparatus

A recording and reproducing apparatus according to the present disclosure includes a first optical pickup configured to record information on either a land track and a groove track, with respect to a recording medium that is able to be recorded in the land track and the groove track, a second optical pickup configured to record information on a track different from a track recorded by the first optical pickup, and a controller configured to cause the first optical pickup to record information if tracks of both sides of a track that the first optical pickup follows are recorded, and to cause the second optical pickup to record information if tracks of both sides of a track that the second optical pickup follows are recorded.

An optical pickup includes a light source; a diffraction elementfor generating a write main beam and a read sub-beam via diffraction; an objective lens; a wavelength plate; a polarization hologram elementhaving a plurality of diffraction regions with different diffraction characteristics, designed so that each diffraction region separates a light beam reflected from the optical storage medium and transmitted through the wavelength plate into a 0order light beam and &#xb1;1order light beams; an actuator; and a photodetectorconfigured to detect a light beam reflected from the optical storage mediumand diffracted by the polarization hologram element. The photodetectorgenerates an RF signal from a detection result concerning a 0order light beam derived from the main beam, generates a focus error signal and a tracking error signal from a detection result concerning one of &#xb1;1order light beams derived from the main beam, and generates a signal indicating that data has been recorded normally from a detection result concerning a 0order light beam derived from the sub-beam.

Optical pickup and optical recording and reproducing device

An exemplary optical pickup comprises: a light source with first and second emission points; an optical branching element which branches light emitted from the first emission point into multiple light beams including a first main beam and first sub-beams and which also branches light emitted from the second emission point into multiple light beams including a second main beam and second sub-beams; an optical system which condenses the multiple light beams produced by the optical branching element onto an optical storage medium, thereby making the first and second main beams form a write light beam spot and a read light beam spot, respectively, on a target recording track on the storage medium and making the first and second sub-beams form reference light beam spots and other light beam spots somewhere on the storage medium other than the target recording track.

Optical pickup and optical read/write apparatus

In one embodiment of the present invention, an optical pickup for writing and reading data on an optical storage medium comprises a diffractive element for diffracting a light beam to split it into multiple light beams. The diffracted light beams includes a zero-order diffracted light beam for writing data on a track of the land or the groove of the optical storage medium and non-zero-order diffracted light beams for reading the data from the track. The diffractive element has first and second diffraction gratings that have mutually different grating vector directions and pitches. The first diffraction grating forms light beam spots on the same track by the non-zero-order and zero-order diffracted light beams. The second diffraction grating forms a light beam spot to extend to both sides of said track, or forms a light beam spot on one side of said track, by the non-zero-order diffracted light beams.

Optical pickup and optical read/write drive

An exemplary optical pickup comprises: first, second and third photosensitive elements which are arranged to respectively receive a main light beam and first and second sub-light beams reflected from an optical storage medium; and fourth and fifth photosensitive elements which are arranged to receive the rest of the light that has also been emitted from a light source but has not been reflected from the optical storage medium. A signal that has been written on the optical storage medium with the main light beam for writing is read by performing an arithmetic operation on the signal output of the second or third photosensitive element and that of the fourth photosensitive element.

In one embodiment, an optical pickup includes an optical system which forms multiple light beams based on the light emitted from a light source and which converges a write beam and a read beam, thereby forming a main spot and a sub-spot, respectively, on an optical storage medium. This optical system converges the write and read beams onto the optical storage medium so that the main spot moves through the same region on the optical storage medium ahead of the sub-spot. The optical pickup further includes a detector for sensing the write and read beams reflected from the storage medium. The detector includes a first photodiodethat receives the reflected light from the main spotR on the storage medium and a second photodiodethat receives a portion of the reflected light from the sub-spotR.

An information recording/reproducing device includes a radiation light sourcesuch as a semiconductor laser, a spatial modulation elementthat splits laser lightemitted from the radiation light sourceinto a large number of diffracted light rays, and an objective lensthat converges the large number of diffracted light rays onto different points. The laser lightemitted from the radiation light sourceis split into a large number of diffracted light rays by the spatial modulation element, the large number of diffracted light rays are converged onto different points in the photosensitive layerof the information recording mediumby the objective lens, and information is recorded in the photosensitive layerof the information recording medium, using an assembly of these converging points. Accordingly, it is possible to provide an information recording device capable of realizing high-contrast recording in which stray light or diffraction has no influence during signal recording.

Information recording device and information reproducing device

Disclosed is an improved DRAW technique for writing data on an optical storage medium and reading the data in parallel. In obtaining the optical power of a first light source, writing user data is temporarily suspended to write non-user data with a second light sourceturned OFF.

Optical read/write apparatus

An optical read/write apparatus as an embodiment of the present invention includes: a light-splitting element configured to split a light beam emitted from a light source into multiple light beams including a write beam and a read beam; an optical system configured to converge the write and read beams onto the same track on an optical storage medium; a photodetector including a light receiving element configured to detect the read beam reflected from the optical storage medium and output an electrical signal; and a divider configured to generate a read signal by dividing the signal detected by the light receiving element by a signal that represents a write modulated component and that is obtained by detecting a part of the light beam emitted from the light source.

An optical information record/playback device of the present invention includes: a light source; a current driver for supplying current to the light source; an optical system for condensing light from the light source onto a recording medium; a monitoring section for monitoring light emission power of the light source; a current driver control section for controlling output current of the current driver; and an arithmetic/control section for controlling an operation of the current driver control section. Before recording information, the arithmetic/control section sequentially conducts a first test light-emission to cause the light source to emit light by using a closed loop circuit and a second test light-emission to cause the light source to emit light by using an open loop circuit, and compares first and second sampling values, which are respectively obtained by sampling the outputs of the monitoring section during the first and second test light-emissions.

Optical information record/playback device

When performing recording/reproduction of information for a given recording layer of an optical disc having three recording layers, influences of reflected light from other recording layers are reduced or removed, thus making it possible to obtain a more stable RF signal or focus error signal. An optical pickup device includes a light source, a collimator lens, an objective lens, a photodetector, and a light shielding member. Among the recording layers of the optical disc, a first layer and a second layer adjoining each other are disposed in the order of the first layer and second layer from near the objective lens. The light shielding member is disposed at a position satisfying the condition d&#x3e;dto block a part of reflected light from the second layer when light is converged on the first layer, where d is an optical path length from the photodetector to the light shielding member; and dis a distance from the photodetector to a position at which reflected light from the second layer becomes focused between the collimator lens and the photodetector.

Growing community of inventors

Osaka, Japan

Kazuo Momoo