5052results about "Optical beam sources" patented technology

A multi-wavelength laser device includes at least two of a blue laser diode, a red laser diode, and an infrared laser diode, which are arranged in the same direction on the same base. One laser light emission point is arranged behind another in increasing order of wavelengths of the laser diodes.

A multi-layered information recording medium including a plurality of recording layers, the multi-layered information recording medium comprising: a user data area for recording user data; and a plurality of spare areas including at least one replacement region, wherein when the user data area includes at least one defect region, the at least one replacement region may be used in place of the at least one defect region, wherein a first spare area of the plurality of spare areas is positioned so as to be contiguous to a first user data area of a first recording layer, a second spare area of the plurality of spare areas is positioned so as to be contiguous to a second user data area of a second recording layer, and the first spare area and the second spare area are positioned approximately at the same radial position on the multi-layered information recording medium.

An optical data storage and retrieval system uses a flying head. The flying head is supported on a moving media having information stored in a plurality of stored data locations thereon. Information is stored in each of the plurality of media locations as physical structures capable of modulating the polarization state of incident light into one of two output polarization states. The flying head includes an optical processing assembly which directs an incident light beam having a source polarization state onto the moving media, accessing successive data locations. A reflected light beam having the source polarization state of the incident light beam modulated by a respective polarization modifying data location into one of the output polarization states is received by the flying head. The optical processing assembly optically transforms the modulated output polarization state of the reflected light beam into two return light beams having differentially modulated intensity related to the output polarization state of the reflected light beam. The two intensity modulated return light beams are optically coupled to a distal differential detector which outputs digital data representing the stored data information for the subject data location. A preferred embodiment includes optical fibers for coupling the incident and return light beams between the detector and the flying head. The optical assembly of a preferred embodiment includes an optical plate having pre-shaped and dimensioned recesses for automatically locating and aligning multiple optical components comprising the assembly. The flying head may also include a servo-controlled micro machined mirror for directing the incident and reflected light beams to and from the media.

An optical pickup apparatus comprises first, second and third light sources to emit light fluxes of wavelength lambda1, lambda2 and lambda3 for conducting recording and / or reproducing information for first, second and third optical information recording mediums having respective protective substrates of thickness t1, t2 and t3 and a diffractive optical element located on a common optical path for the first, second and third light sources. A converged-light spot is formed on the first optical information recording medium with m-th order diffracted-light ray of the wavelength lambda1, on the second optical information recording medium with n-th order diffracted-light ray of the wavelength lambda2, and on the third optical information recording medium with k-th order diffracted-light ray of the wavelength lambda3 generated by the diffractive optical element respectively, wherein one of m, n and k is different from one of other two numbers.

Methods and systems for write compensation for optimizing the performance of a data storage or communication channel are disclosed. In one embodiment, a method comprises determining channel sensitivity to modifications in write signal parameters, detecting systematic errors in a read signal recovered from data written with a first set of write parameters, and adjusting the write signal parameters by an amount determined from the channel sensitivity such that the systematic errors are reduced when data are written with the adjusted write parameters.

A holographic recording and reconstructing apparatus includes a light source having a variable oscillation wavelength; a temperature sensing unit operable to sense temperature; and a control unit operable to record information about a temperature sensed by the temperature sensing unit on a holographic recording medium during recording, to obtain the information about the temperature from the holographic recording medium and obtain a temperature sensed by the temperature sensing unit during reconstruction, to determine the amount of wavelength shift to counteract the effects of a change in the dimension of the holographic recording medium between recording and reconstruction based on the difference between the temperatures, and to shift the oscillation wavelength of the light source by the determined amount.

Provision is made to perform a write trial process in a stable manner at all times in a write trial area for the purpose of determining optimum recording power. Sub-areas of the write trial area are used successively from an inner circumference side of the medium to an outer circumference side of the medium with respect to the spiral direction that extends from the outer circumference side of the medium to the inner circumference side of the medium, and the sub-areas of the write trial area are used successively from the outer circumference side of the medium to the inner circumference side of the medium with respect to the spiral direction that extends from the inner circumference side of the medium to the outer circumference side of the medium With this provision, the write trial process is performed by accessing a sub-area portion of interest without accessing the sub-area portion having undergone the write trial, no matter which record layer is used. Servo control and address read can thus be stabilized. As a result, a seek operation toward the sub-area of interest is also stabilized, thereby achieving a stable write trial process.

An optical disc according to one aspect of this invention has a first field to record first version information, and a second field to record second version information obtained by updating the first version information.

An optical pickup apparatus for reproducing information from an optical information recording medium or for recording information onto an optical information recording medium, is provided with a first light source for emitting first light flux having a first wavelength; a second light source for emitting second light flux having a second wavelength, the first wavelength being different from the second wavelength; a converging optical system having an optical axis and a diffractive portion, and a photo detector; wherein in case that the first light flux passes through the diffractive portion to generate at least one diffracted ray, an amount of n-th ordered diffracted ray of the first light flux is greater than that of any other ordered diffracted ray of the first light flux, and in case that the second light flux passes through the diffractive portion to generate at least one diffracted ray, an amount of n-th ordered diffracted ray of the second light flux is greater than that of any other ordered diffracted ray of the second light flux, where n stands for an integer other than zero.

To provide an optical pickup device and optical disk device capable of realizing at least one of thickness reduction, size reduction and suppression against characteristic deterioration even where coping with various wavelengths of laser including a blue laser. An optical pickup device comprising light sources for respectively emitting a plurality of different wavelengths of light, unit structured for causing at least a part of the light emitted from the light sources to pass a same optical path; and focusing unit for focusing the light. The focusing unit includes at least first and second focusing parts, the first focusing part being to focus mainly a wavelength of light different from a wavelength of light to be mainly focused by the second focusing part.

An information reading and recording apparatus includes a super-resolution cut-off filter having an annular metal reflection film at its center portion and disposed immediately before one of two objective lenses with a higher NA. When reading DVD, the one objective lens with a higher NA with the super-resolution cut-off filter disposed therebefore is positioned at the optical path. When reading CD, the other objective lens with a lower NA is positioned at the optical path. The laser beam reflected by a disk follows backward the incoming optical path to pass through a half mirror, and is received by a photo-detector to be converted into an electrical signal.

In a read / write device for writing and reading a storage medium by way of a heat assisted magnetic recording / reproduction scheme, the read / write device including an elevated slider provided with a semiconductor laser, provided is a heat dissipation mechanism for dissipating heat generated in the elevated slider to an outside of a housing of the read / write device. Further, the storage medium has a second heatsink layer formed of an Al film having a thickness of 50 μm, a backing layer, a heat barrier layer, a first heatsink layer, a magnetic recording layer, and a protection film on a glass substrate. With this arrangement, in a read / write device which performs a heat assisted magnetic recording and reproduction by a semiconductor laser provided on the elevated slider, the occurrence of malfunction due to temperature rises in the storage medium is prevented.

A high-density optical recording medium and method of recording data on the optical recording medium. The optical recording medium includes a plurality of data recording / reproducing surfaces having reflectances for light passing through a pit area, a land / groove area, and a land / groove area on which data are recorded, of a data recording / reproducing surface included between a light source for emitting light and a recording / reproducing surface selected from the plurality of data recording / reproducing surfaces, the reflectances satisfy the expressions r1≧r2≧r3 and {(r1−r3) / r3}≦0.2, where r1, r2 and r3 are the reflectances of the pit area, the land / groove area and the land groove area on which data are recorded, respectively.

In an optical disc in / from which data is recorded or reproduced by irradiating a storage area on the optical disc with a laser, information containing recording velocity information (RVI) for recording / reproduction, which represents a linear velocity different from the standard linear velocity, and write strategy information (WSI) corresponding to the recording velocity information is stored in a land pre-pit or the like on the optical disc.

An optical drive writes information to an optical medium by obtaining a write strategy for the optical medium from a write strategy table embedded in the optical medium. A write module in the optical drive reads an optical drive identification code from the optical medium to select a write strategy associated with the optical drive. The write strategy of the embedded write strategy table that is identified for the optical drive is retrieved by the write module to write information to the optical medium with the optical drive using the identified write strategy. In one embodiment, a time stamp of the identified write strategy retrieved from the optical medium is compared with a time stamp of a write strategy already available to the optical drive to select the most recent write strategy for use by the optical drive. The write strategy table is embedded in the optical medium at manufacture of the optical medium, such as by stamping or burning the data into the optical material of the optical medium.

An optical storage system suitable for optical storage and retrieval of information using a storage medium comprising a substrate, an active layer for retention of the data, and an overlying optical layer, or layers for double-sided. The optical layer serves to produce an evanescent field in or adjacent to the active layer in response to an incident beam of radiation. The evanescent field is frustrated or attenuated by the data in the active layer and produces a signal.

For an optical disk for which a record strategy is not prepared in a memory and an optical disk which cannot obtain a good signal quality by using the record strategy prepared in the memory, test recording is performed by using all record strategies prepared in the memory or properly adopted record strategies by changing the record power. A record strategy providing a relatively high signal quality is selected to record data in the optical disk. The record strategies for such optical disks can be easily set.

An optical information recording medium includes a substrate 1 and two information layers (2, 4) formed on the substrate. The information layer is formed of a thin film showing a change that can be detected optically by irradiation of a light beam 7. A separating layer 3 that is transparent to a wavelength of the light beam 7 is formed between the information layers 2 and 4. Each information layer (2, 4) includes a sector area having sector address portions (9, 13) and data areas (8, 12) for recording information signals, the sector address portion and the data area being divided in the circumferential direction, and a management area (10, 14) for recording identification information about the amount of dislocation between the sector address portions 9 and 14 in the circumferential direction. Thus, the identification information about the amount of dislocation can be recorded, so that demodulation errors during reproduction can be reduced by switching amplification gain or slice level during reproduction according to the identification information. Also, stable data recording can be achieved by switching recording power according to a gate signal.

A method of evaluating the quality of a read signal from the viewpoint of the detection margin of a Viterbi decoder in the PRML method in which a target signal level varies depending on the read signal, and an optical disc apparatus implementing the method. A method of evaluating the quality of a signal pattern comprising a combination of minimum run lengths from the viewpoint of edge shift, and an optical disc apparatus implementing the method. From the target signal level that varies depending on the read signal, a target signal is generated based on a decoding result, and an error target signal is generated in which the decoding result is edge-shifted. The signal quality is evaluated by calculating a Euclidean distance between these signals and the read signal. A virtual state that is not included in the Viterbi decoder and that is less than the minimum run length is defined, and a target signal level for the virtual state is generated using a target signal level table inside the Viterbi decoder, based on the concept of convolution. In this way, the signal quality can be evaluated by the same method as mentioned above even in cases where the pattern of a combination of the minimum run lengths has edge-shifted.

A high-density optical disc such as BD-RE (Blu-ray Disc Rewritable) or BD-ROM, and a recording / reproducing method thereof are disclosed. Diverse additional information such as disc reflectivity information, disc layer information or disc type information is efficiently recorded in a particular information field included in a data unit recorded on the burst cutting area of a high-density optical disc or a particular 1-byte address field included in an address unit recorded on the high-density optical disc so that it can be read when the high-density optical disc is loaded in an optical disc apparatus or when a data recording or reproducing operation for the high-density optical disc is carried out. Accordingly, it is possible to achieve optimal optical power control and automatic gain control or identification of a current position, while enabling a normal data recording or reproducing operation corresponding to the type of the optical disc.

A method of recording and reproducing information in a phase-change optical recording medium by irradiation of an electromagnetic wave for recording, reproducing and / or rewriting information is proposed, wherein when information is recorded in the phase-change optical recording medium by modulating an input signal and conducting pulse width modulation recording, a recording pulse string for recording and rewriting is a continuous electromagnetic wave, and a recording pulse string for input signal, is an electromagnetic wave pulse string having a front-pulse portion fp, a multi-pulse portion mp with a total pulse duration period T and a duty ratio y, and an off-pulse portion op, wherein the duty ratio y is decreased as a recording linear velocity for the phase-change change optical recording medium is increased, whereby multi-speed recording or CAV (constant angular velocity) recording is carried out. An information recording and reproducing apparatus, using the above method, is also proposed.

An optical disk recording apparatus and method utilize a recording beam source, a spatial light modulator that modulates a recording radiation beam into an information beam carrying information and a reference beam, a focusing unit that focuses the information beam and the reference beam onto an information recording layer, an image sensing device that detects intensity distribution of the information beam, and a control unit. The control unit controls the spatial light modulator on the basis of the intensity distribution detected by the image sensing device. An optical disk recording apparatus, and a control method thereof, thereby has a high signal-to-noise ratio.

An information recording apparatus is provided, which can control over the power of light beams emitted from a light source and various types of servo control with higher accuracy. A laser beam is emitted from a semiconductor laser to write information onto an optical disc. A detection signal indicative of the power of the laser beam output from a light-receiving device is sampled and held with a sample and hold circuit via an I-V converter at a timing delayed by the time corresponding to the delay time of the I-V converter. A tracking error generation circuit and a focus error generation circuit generate a tracking error signal and a focus error signal, respectively, on the basis of a detection signal having information about tracking error and focus error and output from a light-receiving device. Sample and hold circuits sample and hold the tracking error signal and the focus error signal at a timing delayed by the time corresponding to the delay time of each of the generation circuits, respectively. Power control, tracking servo, and focus servo are performed using each of the signals held by the sample and hold circuits, respectively.

A thin-film magnetic head that has a configuration in which the element-formed surface and the opposed-to-medium surface are perpendicular to each other, and a light source is sufficiently distanced from the medium surface is provided. The head comprises at least one near-field-light-generating layer for heating a part of a magnetic medium during write operation by generating a near-field light, having a shape tapered toward a head end surface on the opposed-to-medium surface side, and comprising a near-field-light-generating portion having a light-received surface and a tip reaching the head end surface on the opposed-to-medium surface side, and the light-received surface being sloped in respect to the element-formed surface and being provided in a position where an incident light propagating from a head end surface opposite to the opposed-to-medium surface can reach at least a part of the light-received surface.

A near-field optical head has a planar substrate having a first surface, a second surface disposed opposite to the first surface, and an inverted conical or pyramidal hole extending through the first and second surfaces. The conical or pyramidal hole has at least one fine aperture formed at an apex thereof and is disposed on the first surface of the planar substrate. An optical waveguide is disposed on the second surface of the planar substrate for propagating light. A light reflection film is disposed in the optical waveguide for reflecting in the direction of the fine aperture light propagated through the optical waveguide.

Disclosed is a novel multi-layered optical recording media and system for recording and reproducing information data. The multi-layered topical recording media has M information storage decks, and each information storage deck has N information storage layers, and each information storage layer has a pair of information storage structures. Each paired information storage structure has a characteristic wavelength and polarization state, and from which recorded information can be read by a laser beam having similar wavelength and polarization-state characteristics. In the illustrative embodiment, the multi-layered optical recording media of the present invention has MxNx2 information storage layers which can be read using only N laser lines (i.e. spectral components), thereby providing a 2M-fold increase in information storage capacity over prior art systems. The information storage and retrieval system of the present invention is completely backward compatible to allow for the reading of conventional CD-ROM devices.

An optical pickup apparatus includes first and light sources; an objective lens; a spherical aberration correcting optical unit; and a chromatic aberration correcting optical element which includes a diffractive surface on at least one of optical surfaces of the chromatic aberration correcting optical element such that a diffractive structure which is constructed by a plurality of ring-shaped zones separated by fine steps is formed on the diffractive surface, wherein the depth of steps along an optical axis is designed so that n2 which is a diffraction order of a diffracted ray having a largest diffraction efficiency among diffracted rays caused when the second light flux enters into the diffractive structure, is lower order than n1 which is a diffraction order of a diffracted ray having a largest diffraction efficiency among diffracted light rays caused when the second light flux enters into the diffractive structure.

A copy prevention apparatus is provided by an operating system. A data area is shared by a plurality of applications that operate on the operating system. A data area monitoring unit monitors storing of copy prevention data into the data area and a data area copy preventing unit prevents copying of the copy prevention data from the data area based on a result of the monitoring by the data area monitoring unit.