Sharp Kabushiki Kaisha Corporation

Nitto-denko Corporation

Jun Akiyama

Shigemi Maeda

Kunio Kojima

Kiyoe Shigetomi

Masayuki Okamoto

Masato Yamagata

Tomoyuki Miyake

Tetsuya Okumura

Tomiyuki Numata

Toshiharu Inui

Masaki Yamamoto

Hideharu Tajima

Hiroshi Fuji

Shigeo Terashima

Hirohisa Yamada

Yoshihiro Sekimoto

Nobuo Ogata

Yasuhiro Harada

Yasuo Nakata

Hideaki Sato

Masahito Niwa

Masanori Ushioda

An acrylic pressure-sensitive adhesive composition for optical use includes: an acrylic polymer (A) that contains, as a monomer unit, a vinyl monomer having a nitrogen atom in its backbone and that does not substantially contain a carboxyl group-containing monomer; and a (meth)acrylic polymer (B) having a weight average molecular weight of 1000 or more and less than 30000.

Acrylic pressure-sensitive adhesive composition for optical use and acrylic pressure-sensitive adhesive tape for optical use

An acrylic pressure-sensitive adhesive composition contains 100 parts by mass of an acrylic polymer (A), 1 to 70 parts by mass of a (meth)acrylic polymer (B) having a weight average molecular weight (Mw) of 1000&#x2266;Mw&#x3c;30000, and 1 to 50 parts by mass of a hydrogenated tackifying resin (C). The (meth)acrylic polymer (B) is a polymer having a weight average molecular weight smaller than that of the acrylic polymer (A) as a pressure-sensitive adhesive composition, and functions as a tackifying resin along with the hydrogenated tackifying resin (C).

Acrylic pressure-sensitive adhesive composition, acrylic pressure-sensitive adhesive layer, and acrylic pressure-sensitive adhesive tape

The present invention relates to an optical acrylic pressure-sensitive adhesive composition, containing: 100 parts by mass of an acrylic polymer (A) which contains a vinylic monomer having a nitrogen atom in a skeleton thereof as a monomer unit and does not substantially contain a monomer containing a carboxyl group; 1-70 parts by mass of a (meth)acrylic polymer (B) having a weight average molecular weight of 1,000 or greater and less than 30,000; and 1-50 parts by mass of a hydrogenated tackifying resin (C), and an optical acrylic pressure-sensitive adhesive tape including a pressure-sensitive adhesive layer containing the optical acrylic pressure-sensitive adhesive composition.

Optical acrylic pressure-sensitive adhesive composition and optical acrylic pressure-sensitive adhesive tape

An optical information recording medium reproducing apparatusincludes: a signal detecting/extracting sectionextracting, from reproduction signal data, extracted reproduction signal data corresponding to a predetermined data pattern; a calculating circuitcalculating, from the extracted reproduction signal data, a reproducing power control value for controlling laser light reproducing power; and a reproducing power control sectioncontrolling the reproducing power based on the reproducing power control value. The predetermined data pattern is obtained from a space which is sandwiched between marks of &#x3bb;/2NA or longer and is shorter than &#x3bb;/4NA and/or a mark which is sandwiched between spaces of &#x3bb;/2NA or longer and is shorter than &#x3bb;/4NA. Therefore, even when environmental temperature changes in reproduction, the optical information recording medium reproducing apparatus capable of reproducing a super resolution medium including marks each shorter than &#x3bb;/4NA optimally controls laser light reproducing power and prevents degradation of reproduction signal quality.

Optical information recording medium reproducing apparatus, method for reproducing optical information recording medium, program for reproducing optical information recording medium, and computer readable recording medium

A storage medium managing device is provided which can employ a set of management information containing suitable information from a plural sets of management information contained in the storage medium. An optical disc apparatus () manages an optical disc () having a plurality of management areas for containing management information with which data is managed and which is recorded in the management areas in a predetermined sequence. The apparatus includes a management information retrieving section () for reading the management information in the same sequence as the predetermined recording sequence to retrieve primary management information which is management information that is first retrieved normally.

Storage medium managing device, storage medium managing program, and computer-readable medium

A reproducing device includes a detection circuit and an integration circuit. The detection circuit detects a push-pull signal PP. The integration circuit carries out integration processing with respect to one or greater frames of the push-pull signal, and carries out binarization processing with respect to integration results thus obtained, thereby detecting sub data. In the integration circuit, the more the frames to be used for detecting sub data is, the higher the accuracy of the detected sub data is. The reproducing device further includes a control circuit for controlling the total number of the frames to be used for generating valid sub data in the integration circuit. The control circuit controls the total number of the frames in accordance with a result of an error correction made by an error correction circuit.

Data storage medium reproducing device and method for reproducing data storage medium

Reproduction device and method wherein detection of sub-data generated within a controlled time period controls appropriate decryption

A signal evaluation device for evaluating a decoded signal of maximum likelihood decoding includes: a differential metric circuit for finding differential metrics; comparators for judging whether a difference of differential metrics exceeds a predetermined threshold; counters for counting respective output pulses of the comparators; and a controller for finding the probability of the differential metrics falling at or below the predetermined threshold, based on the number of measured samples and the number of samples counted by the counters, and processing the probability by arithmetic operations so as to obtain an index of signal evaluation. With this arrangement, signal evaluation devices for evaluating a recording medium or a recording medium driving device can have a simpler structure and can perform evaluations in a plurality of PR modes.

Signal evaluation devices and signal evaluation methods, signal quality evaluation methods and reproducing devices and recording devices

Provision of a displacement sensor, which detects an amount of shift at an objective lens, and a controller, which adjusts an emitted power based on a value measured by the displacement sensor and compensation data stored in a memory, permits detection by the displacement sensor of the amount of shift at the objective lens as necessary during recording of data, and the controller is capable of causing emission of an optimum emitted power from a laser source to an optical disk based on the measured value obtained and the compensation data. As a result, elimination of effects of fluctuation in effective power due to objective lens shift is permitted, and it is possible to ensure that the effective power of a laser irradiating the active layer will always be maintained at an optimum laser power.

Optical disk apparatus and method for adjusting optical disk apparatus laser power

There is provided a signal evaluation apparatus and signal evaluation method capable of consistently measuring an accurate bit error rate regardless of the distribution profile of the difference of likelihoods (difference metrics) of data sequences. In the signal evaluation apparatus for decoding data sequences by means of maximum likelihood decoding, at least one pair of paths between which a distance has a minimum value are selected by a path selector circuitWith regard to the paths selected by the path selector circuita difference metric obtained by a difference metric calculator circuitis statistically processed by a &#x3bc;- and &#x3c3;-calculator circuitto calculate a bit error rate. Then, the bit error rate is corrected by correction means () on the basis of the number of measurement samples of the paths selected by the path selector circuitand the number of all samples.

Signal evaluation apparatus and signal evaluation method

An optical disk has a recording track constituted by sectors arranged in a concentric or spiral form. Each sector is divided into segments, and each segment includes a data field where data is recorded and a clock mark field having a different light reflectance from that of the data field. The data field in the sector has synchronization patterns S. Hence, a highly reliable optical disk, optical reproduction device, and optical recording device can be offered that are capable of performing recording and reproduction even if a clock mark is defective due to a flaw.

Optical disk, optical reproduction device, and optical recording device

A reproducing light quantity control method for an optical memory device includes the steps of (1) recording test data on an optical recording medium; (2) reproducing the test data recorded on the optical recording medium by changing a reproducing light quantity in a plurality of light quantity values; (3) measuring a quality value and a signal quantity of each of a plurality of reproducing signals from the test data; (4) selecting an optimum reproducing signal quantity from a plurality of reproducing signal quantities in accordance with quality values of the plurality of reproducing signals so as to decide a target value of reproducing signal quantity; and (5) recording the target value on a target value recording region of the optical recording medium. This method reduces the time required to obtain a target value of a reproducing signal quantity and speeds up an operation from installing of the optical recording medium to finishing of preparation for recording and reproducing.

Reproducing light quantity control method for optical memory device, and reproducing light quantity control device, and optical recording medium

A compressed data storage apparatus is provided with a compressing circuit for generating compressed data by compressing digital data from a camera section, a buffer memory for storing the compressed data temporarily, a disk device for storing the compressed data stored in the buffer memory at a rate faster than a rate at which the buffer memory stores the compressed data, and a system controller for increasing a compression ratio of the compressing circuit when detecting that the disk device has become unable to record the data. According to the above arrangement, in the event that the disk device becomes unable to store the data due to vibrations or an impact, the data compression ratio is increased, whereby the rate at which the buffer memory stores the data is reduced. Consequently, the capacity of the buffer memory can be reduced, and therefore, it has become possible to provide an inexpensive compressed data storage apparatus with excellent resistance to vibrations.

Inexpensive compressed data storage apparatus with improved resistance

An information recording and reproduction apparatus uses a recording medium that contains information which prohibits digital copying. A reproduction section reproduces the desired informatiion stored on a first recording medium. A recording section records the reproduced output at a desired position on a second recording medium. However, an erasing section erases the information from the first recording medium during the process of recording that information on the second recording medium. The first and/or second recording medium cannot be removed from the information recording and reproduction apparatus until the erasing operation is completed.

Method and apparatus for controlling digital copying of digitally

An optical disk driving apparatus projects an optical beam onto a certain track on an optical disk and forms a light spot thereon. In an access operation onto an adjacent track, the light spot makes a 3-track jump from the position P1 onto the position P2, then a 2-track jump in the opposite direction onto the position P3. With such an arrangement, since the light spot moves by at least 2 tracks even in an access operation onto an adjacent track, it is possible to detect a zero crossing in a tracking error signal. Therefore, it is enabled to steadily adjust the speed of the movement of an objective lens based on the zero crossing. In consequence, a stable access to an information recording medium can be realized with an inexpensive arrangement.

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Kashihara, Japan

Jun Akiyama