| Patent application number | Description | Published |
|---|
| 20080205236 | OPTICAL INFORMATION RECORDING MEDIUM AND OPTICAL INFORMATION REPRODUCING METHOD - A disc structure for making an inverted optical response through a super-resolution process using a recorded mark portion and a space portion, which is realized to amplify a signal amplitude and solve a conventional problem that a conventional super-resolution technique can obtain only small signals, since the super-resolution area is reduced to realize high density recording of data. | 08-28-2008 |
| 20080267050 | INFORMATION RECORDING MEDIA AND PLAYBACK POWER DETERMINING METHOD FOR SIGNAL PLAYBACK - A super resolution optical disk medium having an array of pits less than or equal in size to optical resolution is disclosed, wherein the pits are read by using heat generated within the medium upon irradiation of a read laser beam. A playback power determination method for use with the disk is also disclosed. A playback power level at which super resolution occurs is determined based on a bit error rate (bER) of the optical disk and the amplitude of a playback signal having a predefined signal pattern. In the optical disk, NR/SR is set to one (1) or less, where SR is the signal obtained from a high-temperature region in case the playback is performed in the state that the super resolution occurs, and NR is the amplitude of a signal which is read in the absence of such super resolution. | 10-30-2008 |
| 20080285431 | Optical disk medium and tracking method - A super-resolution material is formed in only a data pit, in a low temperature state of the super-resolution material, reflectivity of each of a pit portion and a space portion and an optical phase difference therebetween are set to be sufficiently small, in a high temperature state, and at least the optical phase difference between the pit and the space is set to be larger than the aforementioned value in an absolute value. Accordingly, by conducting irradiation with an appropriate read power by which substantially only one data track width can be heated to a high temperature state, a good push-pull signal can be obtained even with a track pitch being less than a diffraction limit. At the same time, by an optical device having functions such as a switching means with a DPP type, an offset correcting means of the push-pull signal due to lens shift, a shaping means of the push-pull signal, a learning means of read power, and the like, there is provided an optical disk device that corresponds to the optical disk medium of the present invention and achieves an increase in capacity. | 11-20-2008 |
| 20090040897 | Reproducing signal measuring method, signal reproducing apparatus, and optical recording medium - Regarding a signal recorded with a first frequency in a recording area on a specific first recording layer and a signal recorded with a second frequency different from the first frequency in a recording area on a second recording layer which might cause interlayer crosstalk in relation to the first recording layer, a reproducing signal measurement method for a multilayer optical recording medium having at least three recording layers includes reproducing the signal recorded in the recording area on the first recording layer, separating signals recorded respectively with the first and second frequencies, discriminating signal amplitude of the first frequency and a maximum value in signal amplitude of the second frequency, and calculating a signal amplitude ratio between them to measure interlayer crosstalk contained in the signal reproduced from the recording area on the first recording layer. Thus, the interlayer crosstalk quantity caused by unnecessary light can be measured quantitatively. | 02-12-2009 |
| 20090046557 | PRML (Partial Response Maximum Likelihood) information reproducing method and information reproducing apparatus for implementing the same - An information reproducing method using PRML technology which provides asymmetry compensation and also assures media interchangeability. To compensate for asymmetry, target levels are basically adapted to readout signals and either restriction type (1) (time reversal and level reversal symmetry) or restriction type (2) (time reversal symmetry) is imposed between target levels. As a consequence, asymmetry compensation is made regardless of a readout signal distortion such as mark shift which might deteriorate media interchangeability. | 02-19-2009 |
| 20090052595 | Method of evaluating a readout signal, and optical disc apparatus - A method and optical disc apparatus for evaluating a quality of a read signal adapted to the PRML method by evaluating a binary code decoded from the read signal obtained by a head, in which an error bit sequence having one bit edge shift from the binary code is generated, a Euclidian distance is calculated on both a correct bit sequence and the error bit sequence with respect to a predetermined target signal level, assuming that the binary code is the correct bit sequence, a Euclidian distance difference between the Euclidian distance on the correct bit sequence and the Euclidian distance on the error bit sequence is calculated, an average Euclidian distance from the target signal level is calculated, a normalized sequence error is calculated, the binary code is evaluated using the normalized sequence error. | 02-26-2009 |
| 20090080311 | OPTICAL INFORMATION REPRODUCING METHOD, OPTICAL INFORMATION REPRODUCING DEVICE, AND OPTICAL INFORMATION RECORDING MEDIUM - In a super-resolution optical disk for the purpose of achieving an increase in the density of recording data by reproducing a recording mark smaller than optical resolution, the optimum reproduction power needs to be determined since the quality of a super-resolution reproduced signal strongly depends on the reproduction laser power. However, since the track error signal required for tracking servo also depends on the reproduction power, there is a need for a method for determining the reproduction power taking into account both the stabilization of tracking servo and a quality improvement of the reproduction signal. The reproduction power is changed under conditions with focusing servo applied but without application of tracking servo. Thereby, a cross track signal is detected to identify a reproduction power region that leads to quality improvement of both a reproduction signal and a track error signal. | 03-26-2009 |
| 20090086602 | OPTICAL INFORMATION REPRODUCING METHOD, OPTICAL INFORMATION REPRODUCING APPARATUS AND OPTICAL INFORMATION RECORDING MEDIUM - Reproduction on an optical recording medium having plural information layers involves the problem of distortion occurring due to interlayer crosstalk and hence deterioration in the quality of a readout signal. At a predetermined radius, a correction coefficient for correcting the amount of fluctuation components is calculated from a readout signal with distortion due to the interlayer crosstalk, and then is stored. The stored correction coefficient is used to eliminate crosstalk components and to correct readout signal fluctuation during reproduction on a predetermined area. In this way, the original readout signal without interlayer crosstalk components can be obtained, so that good-quality reproduction characteristics can be achieved. | 04-02-2009 |
| 20090106627 | Digital information reproduction method - An optical disc using super-resolution effects that achieves higher-density recording exceeding the optical resolution suffers from the signal-quality degradation caused by the normal resolution component included in the reproduction signal. To address this problem, a data reproduction method is provided. In the method, characteristic error patterns are identified and parity check codes in conformity with run-length limited coding are used to carry out efficient and reliable error correction. Error patterns caused by the normal resolution crosstalk are localized in the leading edges of a mark following a long space and in the trailing edges of a long mark. Whether an error exists in the data is determined by use of the parity check codes. When an error occurs, a pattern in which an error is most likely to occur is selected from the above-mentioned patterns by taking account of the edge shift direction, and then the error therein is corrected. | 04-23-2009 |
| 20090136219 | Information Read Device And Read Signal Processing Circuit - An information read device enabling obtaining of a data pattern recorded on an information recording medium as a readout signal, includes an analog to digital converter for converting the readout signal to a digital signal for a predetermined clock, a phase locked loop circuit that supplies the clock used in the analog to digital converter, a first FIR filter for equalizing the digital-converted digital signal under a first equalization condition, a Viterbi decoder to decode outputs of the FIR filter into binary data, wherein the phase locked loop circuit enables detection of a cycle slip of the phase locked loop circuit, and a detector which detects the cycle slip of the phase locked loop circuit. The FIR filter returns tap coefficients of the FIR filter, and the Vitabi decoder returns a target level of a decode operation to an initial value when an out-breaking of the cycle slip occurs. | 05-28-2009 |
| 20090252005 | Test writing method and information recording device - The object of the present invention is to provide a test writing method for seeking the optimum write power correctly and in a short time under a high speed recording condition in a test writing method and an information recording device for recording information by forming different marks from the unrecorded part by injecting energy onto the recording medium. To achieve the above object, even number length marks and odd number length marks are separately test written in the 2T strategy to seek the respective optimum write power. Due to the possibility of enhancing the precision of test writing, a good recording ability can be obtained. | 10-08-2009 |
| 20100083295 | INFORMATION RECORDING MEDIUM AND OPTICAL RECORDING/REPRODUCING APPARATUS - When a super resolution technology for optical disks is used in a situation where optical disk management information is formed with a signal that cannot be reproduced by a reproduction method based on a conventional optical disk technology, optical disk drives cannot make recording adjustments and/or reproduction adjustments. | 04-01-2010 |
| 20100195462 | METHOD OF EVALUATING REPRODUCE SIGNAL AND OPTICAL DISC DRIVE - A highly efficient and reliable reproduced signal evaluation method and an optical disc drive using that method in which assuming that the number of 2T's appearing successively in a predetermined evaluation bitstream is i, the evaluation bitstream is divided into a main bitstream (5+2i) long and sub bitstreams at the ends of the main bitstream. The check process to determine whether a predetermined evaluation bitstream is included in the binarized bitstreams is replaced with a main bitstream agreement check. This can prevent an increase in the circuit size. At the same time, by separately summing up for each main bitstream the calculated results of Euclidean distance between the reproduced signal and the target signal corresponding to the evaluation bitstream, the size of an evaluation summing circuit can be reduced. | 08-05-2010 |
| 20100232268 | METHOD AND APPARATUS FOR RECORDING AND REPRODUCING OPTICAL INFORMATION, AND RECORDING MEDIUM - Ordinary optical disks need the resetting of recording conditions in the course of recording to cope with changes in ambient temperature, laser temperature, and medium's recording sensitivity. Optical disks for super-resolution reproduction which are intended to reproduce record marks smaller than the optical resolution, thereby increasing the recording density, need the resetting of recording conditions as well as the condition of super-resolution reproduction because the quality of reproduced signals depends largely on the power for super-resolution reproduction. The power for recording as well as the power for super-resolution reproduction is therefore changed in the course of test recording to detect the deviation from the optimum value of the recording condition to obtain the optimum recording power. In this case, it is also desirable to change the power for super-resolution reproduction in proportion to the power for recording. | 09-16-2010 |
| 20100260025 | ADJUSTING METHOD FOR RECORDING CONDITION AND OPTICAL DISC DEVICE - A method for evaluating reproduced signal wherein when Euclidean distance is calculated by judging the coincidence between a binary bit array and a predetermined evaluation bit array in the evaluation of the quality of reproduced signal, in a large capacity optical disc system with constraint length equal to or greater than 5, the assumption is made that the continuous 2T count included in a predetermined evaluation bit array is denoted by i and that each evaluation bit array is composed of a main bit array having a bit length of (5+2i) and auxiliary bit arrays added before and after the main bit array; judgment on whether binary bit arrays include the predetermined evaluation bit array, is concentrated on the coincidence judgment of the main bit arrays; and at the same time, the Euclidean distance between the reproduced signal and the target signal corresponding to the evaluation bit array is calculated with respect to each main bit array and the results of such calculations are separated and counted. | 10-14-2010 |
| 20100271917 | TEST-WRITE METHOD, INFORMATION RECORDING METHOD, AND INFORMATION RECORDING APPARATUS - A test-write method for accurately and quickly determining recording conditions, and an apparatus suitable therefor. In a 2T-based strategy, recording pulse conditions are determined by separately test-writing an even-number length mark and an odd-number length mark, and then the relative positions of the even-number length mark and the odd-number length mark at the recording pulse start time are adjusted. | 10-28-2010 |
| 20100284257 | ADJUSTING METHOD FOR RECORDING CONDITION AND OPTICAL DISC DEVICE - In a optical disc system with constraint length equal to or greater than 5, under assumption that continuous 2T count included in a predetermined evaluation bit array is denoted by i and that length of evaluation bit array of interest is given by (5+2 | 11-11-2010 |
| 20100290328 | REPRODUCING POWER ADJUSTING METHOD, OPTICAL INFORMATION RECORDING/REPRODUCING APPARATUS AND INFORMATION RECORDING MEDIA - By referring to a table of reproducing conditions and medium specific parameters, stored in an optical disc or optical disc apparatus and/or generated by the optical disc apparatus, the medium specific parameters to be used for performing reproducing power adjustment are changed in accordance with the reproducing condition to execute reproducing power adjustment. | 11-18-2010 |
| 20110026383 | REPRODUCED SIGNAL EVALUATION METHOD AND WRITE ADJUSTMENT METHOD - The present invention aims to provide a reproduced signal evaluation method and a write adjustment method for offering a Blu-ray disc having a large storage capacity with excellent media compatibility. An evaluation index L-SEAT is calculated through signed addition using a Euclidean distance difference calculated from at least one of target signals in which a focused edge is shifted to the right and left, and the quality of the reproduced signal is evaluated based on the evaluation index. Write condition adjustment using the index enables write adjustment not depending on SNR and achieving high adjustment accuracy. | 02-03-2011 |
| 20110085238 | OPTICAL ELEMENT AND OPTICAL APPARATUS - The present invention provides a small and inexpensive optical element that integrates a reflecting mirror and a wave plate function. A reflecting wave plate is configured by arranging a periodic metal comb-like structure whose pitch is equal to or below a wavelength and a mirror structure with a distance equal to or below a coherence length. | 04-14-2011 |
