Patents by Inventor Shigemi Maeda

Shigemi Maeda has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20100246344
    Abstract: In an optical information storage medium reproduction apparatus (10) for reproducing an optical information storage medium including a plurality of information recording layers each including a recording mark having a length shorter than an optical system resolution limit, reproduction laser power for reading an information recording layer closest to a reproduction-laser-incident surface of the optical information storage medium is set to be lower than reproduction laser power for reading an information recording layer farthest from the reproduction-laser-incident surface but not lower than minimum reproduction laser power that satisfies a reproduction signal characteristic that the optical information storage medium reproduction apparatus (10) requires.
    Type: Application
    Filed: June 11, 2010
    Publication date: September 30, 2010
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: Masaki Yamamoto, Hirohisa Yamada, Yasuhiro Harada, Go Mori, Hideharu Tajima, Shigemi Maeda, Yoshiteru Murakami
  • Publication number: 20100232269
    Abstract: In an optical information storage medium reproduction apparatus (10) for reproducing an optical information storage medium including a plurality of information recording layers each including a recording mark having a length shorter than an optical system resolution limit, reproduction laser power for reading an information recording layer closest to a reproduction-laser-incident surface of the optical information storage medium is set to be lower than reproduction laser power for reading an information recording layer farthest from the reproduction-laser-incident surface but not lower than minimum reproduction laser power that satisfies a reproduction signal characteristic that the optical information storage medium reproduction apparatus (10) requires.
    Type: Application
    Filed: September 25, 2008
    Publication date: September 16, 2010
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Masaki Yamamoto, Hirohisa Yamada, Yasuhiro Harada, Go Mori, Hideharu Tajima, Shigemi Maeda, Yoshiteru Murakami
  • Publication number: 20100188958
    Abstract: A recording parameter setting device includes a trial recording parameter setting section (23) and a reproduced signal quality judging section (26). The trial recording parameter setting section (23) inquires, in accordance with the recording information, a storage section (3) containing recording parameters used for controlling heat of recording marks, and sets a trial recording parameter, wherein (a) the recording parameters are used for controlling heat of at least rear edges, (b) the recording parameters are classified in accordance with recording mark lengths, and (c) recording parameters of a predetermined recording mark length or longer are classified into a same group. The reproduced signal quality judging section (26) judges whether or not a reproduced signal obtained by reproduction of the trial recording carried out in accordance with the trial recording parameter satisfies a predetermined reproduced signal quality.
    Type: Application
    Filed: March 31, 2010
    Publication date: July 29, 2010
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Yoshihisa Adachi, Shigemi Maeda, Atsushi Etoh
  • Publication number: 20100188948
    Abstract: A recording parameter setting device includes a trial recording parameter setting section (23) and a reproduced signal quality judging section (26). The trial recording parameter setting section (23) inquires, in accordance with the recording information, a storage section (3) containing recording parameters used for controlling heat of recording marks, and sets a trial recording parameter, wherein (a) the recording parameters are used for controlling heat of at least rear edges, (b) the recording parameters are classified in accordance with recording mark lengths, and (c) recording parameters of a predetermined recording mark length or longer are classified into a same group. The reproduced signal quality judging section (26) judges whether or not a reproduced signal obtained by reproduction of the trial recording carried out in accordance with the trial recording parameter satisfies a predetermined reproduced signal quality.
    Type: Application
    Filed: March 31, 2010
    Publication date: July 29, 2010
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Yoshihisa Adachi, Shigemi Maeda, Atsushi Etoh
  • Publication number: 20100188956
    Abstract: A recording parameter setting device includes a trial recording parameter setting section (23) and a reproduced signal quality judging section (26). The trial recording parameter setting section (23) inquires, in accordance with the recording information, a storage section (3) containing recording parameters used for controlling heat of recording marks, and sets a trial recording parameter, wherein (a) the recording parameters are used for controlling heat of at least rear edges, (b) the recording parameters are classified in accordance with recording mark lengths, and (c) recording parameters of a predetermined recording mark length or longer are classified into a same group. The reproduced signal quality judging section (26) judges whether or not a reproduced signal obtained by reproduction of the trial recording carried out in accordance with the trial recording parameter satisfies a predetermined reproduced signal quality.
    Type: Application
    Filed: March 31, 2010
    Publication date: July 29, 2010
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Yoshihisa Adachi, Shigemi Maeda, Atsushi Etoh
  • Publication number: 20100188955
    Abstract: A recording parameter setting device includes a trial recording parameter setting section (23) and a reproduced signal quality judging section (26). The trial recording parameter setting section (23) inquires, in accordance with the recording information, a storage section (3) containing recording parameters used for controlling heat of recording marks, and sets a trial recording parameter, wherein (a) the recording parameters are used for controlling heat of at least rear edges, (b) the recording parameters are classified in accordance with recording mark lengths, and (c) recording parameters of a predetermined recording mark length or longer are classified into a same group. The reproduced signal quality judging section (26) judges whether or not a reproduced signal obtained by reproduction of the trial recording carried out in accordance with the trial recording parameter satisfies a predetermined reproduced signal quality.
    Type: Application
    Filed: March 31, 2010
    Publication date: July 29, 2010
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Yoshihisa Adachi, Shigemi Maeda, Atsushi Etoh
  • Publication number: 20100188949
    Abstract: A recording parameter setting device includes a trial recording parameter setting section (23) and a reproduced signal quality judging section (26). The trial recording parameter setting section (23) inquires, in accordance with the recording information, a storage section (3) containing recording parameters used for controlling heat of recording marks, and sets a trial recording parameter, wherein (a) the recording parameters are used for controlling heat of at least rear edges, (b) the recording parameters are classified in accordance with recording mark lengths, and (c) recording parameters of a predetermined recording mark length or longer are classified into a same group. The reproduced signal quality judging section (26) judges whether or not a reproduced signal obtained by reproduction of the trial recording carried out in accordance with the trial recording parameter satisfies a predetermined reproduced signal quality.
    Type: Application
    Filed: March 31, 2010
    Publication date: July 29, 2010
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Yoshihisa Adachi, Shigemi Maeda, Atsushi Etoh
  • Publication number: 20100188954
    Abstract: A recording parameter setting device includes a trial recording parameter setting section (23) and a reproduced signal quality judging section (26). The trial recording parameter setting section (23) inquires, in accordance with the recording information, a storage section (3) containing recording parameters used for controlling heat of recording marks, and sets a trial recording parameter, wherein (a) the recording parameters are used for controlling heat of at least rear edges, (b) the recording parameters are classified in accordance with recording mark lengths, and (c) recording parameters of a predetermined recording mark length or longer are classified into a same group. The reproduced signal quality judging section (26) judges whether or not a reproduced signal obtained by reproduction of the trial recording carried out in accordance with the trial recording parameter satisfies a predetermined reproduced signal quality.
    Type: Application
    Filed: March 31, 2010
    Publication date: July 29, 2010
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Yoshihisa Adachi, Shigemi Maeda, Atsushi Etoh
  • Publication number: 20100165808
    Abstract: There are provided at least a first information storage area 20A and a second information storage area 40A. The first information storage area 20A contains, in advance, an OS or mpeg data. The second information storage area 40A is either write-once or rewriteable and available for writing OS update information or movie correction information. The configuration enables easy backup and restoration of software, content, and various information including update information for use by the software and content with reduced user time and workload.
    Type: Application
    Filed: December 22, 2009
    Publication date: July 1, 2010
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Yasuhiro Harada, Shigemi Maeda, Hideharu Tajima, Tetsuya Hayashi, Atsushi Etoh
  • Publication number: 20100046333
    Abstract: This invention allows super-resolution reproduction with which a better bER value is attainable, when information is recorded by a random pattern including a mark length not longer than a resolution limit, by use of a highly versatile signal decoding method. Information is recorded as marks and spaces coded by RLL(1, 7) modulation, which each of the marks and spaces have one of a plurality of lengths, and 2T marks and 2T spaces of the marks and spaces being formed are shorter than 0.12 ?m. An information recording layer (20) includes a reproduction film (21) and a reflective film (22) which are provided in this order from a side from which reproducing light is incident, which reproduction film is made of (i) zinc oxide, (ii) strontium titanate, (iii) titanium oxide, (iv) cerium oxide, or (v) a material including at least one of the (i) through (iv), and which reflective film is made of tantalum or titanium.
    Type: Application
    Filed: May 30, 2008
    Publication date: February 25, 2010
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Go Mori, Hirohisa Yamada, Masaki Yamamoto, Yasuhiro Harada, Hideharu Tajima, Shigemi Maeda, Yoshiteru Murakami
  • Publication number: 20090303629
    Abstract: A magnetic recording/reproducing apparatus 100 includes: a magnetic head 1; a magnetic recording medium 2; a spindle 3 and a spindle motor 4; a suspension arm 5; a voice coil motor 6; and a control unit 7. The control unit 7 has: a motor driver 8; a head amplifier 9; a read/write channel 10; a laser driver 11; and a controller 12. The controller 12 has: a preliminary recording unit 13; a judgment unit 14; an extraction unit 15; a drive condition determining unit 16; and a preliminary recording terminating unit 17. Based on a reproduction signal evaluation value obtained using these units and a predetermined reference value, a drive condition is determined which is suitable for recording onto the magnetic recording medium 2.
    Type: Application
    Filed: November 7, 2007
    Publication date: December 10, 2009
    Inventors: Ikuo Nakano, Yoshiteru Murakami, Shigemi Maeda
  • Publication number: 20090116354
    Abstract: A recording parameter setting device including a trial recording parameter setting section and a reproduced signal quality judging section. The reproduced signal quality judging section judges whether or not a reproduced signal obtained by reproduction of the trial recording carried out in accordance with the trial recording parameter satisfies a predetermined reproduced signal quality. If no, the recording parameters of the predetermined recording mark length or longer are further classified into detailed groups and trial recording is carried out again. If the reproduced signal satisfies the predetermined reproduced signal quality, the reproduced signal quality judging section sets the trial recording parameters as a recording parameter. This makes it possible to form a recording mark capable of surely providing a good reproduced signal quality while the number of recording parameters to be used is reduced.
    Type: Application
    Filed: October 16, 2008
    Publication date: May 7, 2009
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Yoshihisa Adachi, Shigemi Maeda, Atsushi Etoh
  • Publication number: 20090073835
    Abstract: A recording parameter setting device includes a trial recording parameter setting section (23) and a reproduced signal quality judging section (26). The trial recording parameter setting section (23) inquires, in accordance with the recording information, a storage section (3) containing recording parameters used for controlling heat of recording marks, and sets a trial recording parameter, wherein (a) the recording parameters are used for controlling heat of at least rear edges, (b) the recording parameters are classified in accordance with recording mark lengths, and (c) recording parameters of a predetermined recording mark length or longer are classified into a same group. The reproduced signal quality judging section (26) judges whether or not a reproduced signal obtained by reproduction of the trial recording carried out in accordance with the trial recording parameter satisfies a predetermined reproduced signal quality.
    Type: Application
    Filed: March 27, 2007
    Publication date: March 19, 2009
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Yoshihisa Adachi, Shigemi Maeda, Atsushi Etoh
  • Patent number: 7474598
    Abstract: An optical reproducing device is provided with predetermined length mark signal measurement means which measures amplitude values of a 2T mark and an 8T mark, which are a short reproducing power control mark and a long reproducing power control marks, respectively, from information data recorded in an magneto-optical disk. Reproducing power of a light beam is controlled by a laser power control circuit, based on the amplitude values of the 2T mark and the 8T mark. The predetermined length mark signal measurement means detects a specific pattern including the 2T mark from a bit arrangement pattern of the information data, and measures the amplitude value of the 2T mark correponding only to the 2T mark included in the specific pattern. This structure can provide an optical reproducing device which can maintain the reproducing power at an optimum value and reduce the probability of reading errors, without reducing the utilization ratio of an optical recording medium.
    Type: Grant
    Filed: February 25, 2002
    Date of Patent: January 6, 2009
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Tetsuya Okumura, Shigemi Maeda
  • Patent number: 7339864
    Abstract: A recording pulse condition for obtaining a reproduction result which fulfills predetermined signal quality is sought by performing testwrite and reproduction after uniformly changing predetermined recording pulse conditions corresponding to all mark lengths (S1, S2). If good result is not obtained, a recording pulse condition for obtaining a reproduction result which fulfills predetermined signal quality is sought by performing testwrite and reproduction after changing a predetermined recording pulse condition corresponding to at least one mark length (S4, S5). Then, a recording pulse condition is determined (S3). Thus provided are method and apparatus for efficiently setting such a recording condition that can reduce the influence of difference in characteristics of writable optical disks and difference in characteristics of optical recording and reproducing apparatuses, and to provide a recording and reproducing apparatus.
    Type: Grant
    Filed: December 2, 2004
    Date of Patent: March 4, 2008
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yoshihisa Adachi, Shigemi Maeda
  • Patent number: 7206351
    Abstract: 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.
    Type: Grant
    Filed: May 24, 2002
    Date of Patent: April 17, 2007
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Tetsuya Okumura, Jun Akiyama, Tomiyuki Numata, Shigemi Maeda, Masanori Ushioda
  • Patent number: 7194674
    Abstract: The waveform equalizing device includes: an FIR filter for generating an equalized signal pattern y(i, n) on the basis of equalization of a waveform of the reproduced signal pattern u(i, n); a Viterbi decoding circuit for detecting a path metric difference s(n) between a correct path determined as a survivor path and an error path which fails to survive the correct path in Viterbi decoding based on the equalized signal pattern y(i, n); a target register for setting a target value ds for the path metric difference s(n); and a tap coefficients update circuit for adapting the equalization according to an error of the detected path metric difference from the target value. The tap coefficients update circuit adapts equalization properties so that the mean square error is minimized, thereby achieving a satisfactory result in lowering the error rate.
    Type: Grant
    Filed: July 22, 2003
    Date of Patent: March 20, 2007
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Tetsuya Okumura, Shigemi Maeda
  • Patent number: 7061849
    Abstract: In a recording method for an optical disk, an optical disk is used, in which concave and convex areas formed as concave and convex sections on the disk substrate are arranged along a track with constant intervals and a recording area for recording data of a predetermined number of units is placed between the concave and convex areas arranged with constant intervals. Upon recording information on this optical disk, a two-dimensional array is formed by adding addition data to input data, a first encoding parity is added to the two dimensional array by carrying out a first encoding process that forms a code sequence by using a data alignment in a diagonal direction, and a second encoding parity is added to the resulting two dimensional array by carrying out a second encoding process that forms a code sequence by using a data alignment in a row direction so that a second two dimensional array is formed. Then, data is successively recorded in the row direction.
    Type: Grant
    Filed: November 22, 2000
    Date of Patent: June 13, 2006
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takeshi Yamaguchi, Shigemi Maeda
  • Patent number: 7027370
    Abstract: An optical recording device includes a recording condition determining section for determining recording conditions for a track by performing test writing with respect to the track which is, for example, either a land or a groove of a magneto-optical disk, a recording condition computing section for performing computation in accordance with computation-use information based on the recording conditions for the track so as to determine recording conditions for the other track, a track switch section for switching tracks to be used for test writing, and a computation-use information managing section for correcting the computation-use information based on respective results of test writing before and after the switch, thereby determining recording conditions for one of the tracks in short time by computation, while, because the computation-use information is corrected based on the results of test writing, improving accuracy in recording conditions obtained by computation.
    Type: Grant
    Filed: September 26, 2001
    Date of Patent: April 11, 2006
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yoshihisa Adachi, Shigemi Maeda
  • Patent number: 6967917
    Abstract: An optical disk using both grooves and lands as a recording track is provided with {circle around (1)} a data area for recording/reproducing data and {circle around (2)} DMAs (Data Management Areas) for managing a defective sector in the data area. The DMAs include four DMAs A–D all formed on the lands. The DMA B(D) is formed behind the ending sector of the DMA A(C). This arrangement realizes a DMA format having high resistance to defects and improving a processing rate. Consequently, highly reliable optical disk and optical disk apparatus can be provided.
    Type: Grant
    Filed: April 28, 2000
    Date of Patent: November 22, 2005
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Tomiyuki Numata, Shigemi Maeda