Servo Loop Gain/switching Control Patents (Class 369/44.29)
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Patent number: 7020052Abstract: A storage medium is provided having a relatively large number of relatively small servo sectors. The storage medium includes a plurality of tracks. Each track includes a plurality of data sectors and a plurality of servo sectors. Each servo sector includes a plurality of servo marks and a synchronization gap. A plurality of first servo sectors includes a synchronization gap having a first length and a plurality of second servo sectors includes a synchronization gap having a second length. The first length is different from the second length, whereby, an unsynchronized reading device may recognize the longer synchronization gap and synchronize to the servo sector and a synchronized reading device may remain synchronized by recognizing the shorter synchronization gap.Type: GrantFiled: August 30, 2001Date of Patent: March 28, 2006Assignee: Iomega CorporationInventors: Boyd Shelton, Charlie M. Monroe, Jr.
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Patent number: 7016272Abstract: Optical disk device, in which a tracking adjustment system and sled adjustment system are controlled independently, has offset value acquisition capability, which detects the tracking drive signals output from tracking adjustment system for one lap around optical disk and acquires multiple tracking drive offset values. Such device also has offset representative value computation capability, which computes an offset representative value from multiple tracking drive offset values, as well as an offset value comparison capability, which compares the offset center value in the state in which no tracking adjustment control is done, and the offset representative value, as well as a sled drive decision means capability, which decides the drive of sled adjustment system 36 based on the comparison result.Type: GrantFiled: November 7, 2001Date of Patent: March 21, 2006Assignee: Sony Computer Entertainment Inc.Inventor: Takashi Enokihara
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Patent number: 7016273Abstract: The present invention provides an optical pickup device that is resistant to noise in a signal or an RF signal outputted from each light receiving member. Current signals outputted from the light receiving members are converted into voltage signals by I/V converters. The voltage signals are then added up by an adder, and then the added voltage signal is attenuated by an attenuator, so as to obtain an RF signal having the same signal level as the voltage signal outputted from each I/V converter. The RF signal is then transmitted from the optical pickup device to a circuit substrate through a signal line.Type: GrantFiled: January 16, 2004Date of Patent: March 21, 2006Assignee: Ricoh Company, Ltd.Inventor: Hiroshi Maegawa
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Patent number: 7009917Abstract: A layer jump control apparatus of an optical drive. The layer jump control apparatus has a pick up head, a preamplifier, a controller producing a focusing control signal FC, a low pass filter for receiving FC and producing a layer distance balancing signal LC, and a driving device to send a driving force to the pick up head. When the optical drive does not perform the layer jump process, the driving device receives FC. When the optical drive performs the layer jump process, the driving device receives a kicking signal and LB to determine the driving force in the kicking process; the driving device receives a braking signal and LB to determine the driving force in when the optical drive performs the braking process; and the driving device receives LB to determine the driving force in the holding process and the waiting process.Type: GrantFiled: November 28, 2001Date of Patent: March 7, 2006Assignee: Mediatek IncorporationInventors: Shih-Chun Chiang, Chen-Hsing Lo
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Patent number: 7009918Abstract: The present invention provides an information storage apparatus that generates a tracking error signal based on a detection signal, and performs various control operations based on the tracking error signal. When the operation mode is a seek operation mode, the information storage apparatus generates a tracking error signal by holding the peak value of the detection signal. When the operation mode is a tracking operation mode, the information storage apparatus generates a tracking error signal directly from the detection signal. With this information storage apparatus, stable control operations can be performed, regardless of changes of conditions.Type: GrantFiled: February 22, 2001Date of Patent: March 7, 2006Assignee: Fujitsu LimitedInventors: Masatsugu Nishida, Toru Ikeda, Masaharu Moritsugu
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Patent number: 7006423Abstract: A mark detecting circuit that stably and reliably detects the marks for address information from an optical disk having tracks formed in a spiral shape and having waviness with a fixed period. In the land pre-pit signal extracting portion 12, by means of first bottom envelope circuit 32 with a high tracking speed, first bottom envelope signal Sbtm1 that represents at high sensitivity the bottom envelope of push-pull signal (SA+SB)?(SC+SD) is generated; and, by means of second bottom envelope circuit 34 with a low tracking speed, second bottom envelope signal Sbtm2 that represents at low sensitivity the bottom envelope waveform of push-pull signal (SA+SB)?(SC+SD) is generated. Then, with the signal, obtained by level shift treatment of said second bottom envelope signal Sbtm2 using offset circuit 36, used as threshold signal Sref, first bottom envelope signal Sbtm1 is converted to a binary form. And land pre-pit signal SLPP is extracted from push-pull signal (SA+SB)?(SC+SD).Type: GrantFiled: November 10, 2003Date of Patent: February 28, 2006Assignee: Texas Instruments IncorporatedInventors: Koyu Yamanoi, Eiichi Saiki
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Patent number: 7002880Abstract: An optical disk drive for accessing data stored on a compact disc has a housing, a sled sliding inside the housing, a driving device for driving the sled, an actuator installed on the sled, a servo device for providing a push force to drive the actuator, a control circuitry for controlling operations of the optical disk drive, an adaptive compensator, and an error signal generation circuit. The actuator can move within a predetermined range on the sled, wherein the predetermined range includes a linear region and a non-linear region. It is desirable to keep the actuator within the linear region of the predetermined range. For this, an adaptive compensator is used to provide a supplementary force to the sled when the actuator is near the non-linear region.Type: GrantFiled: February 17, 2004Date of Patent: February 21, 2006Assignee: VIA Technologies Inc.Inventors: Jia-Shing Sheu, Cheng-Hung Chen
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Patent number: 7002881Abstract: The object of the invention is to provide a light receiving amplification element applicable to an optical pickup apparatus comprising a semiconductor two-wavelength laser element and one condensing lens. The light receiving amplification element is provided with a plurality of light receiving portions corresponding to different wavelengths, a plurality of trans-impedance type amplifiers connected to the light receiving portions according to the different wavelengths and adaptable to the different wavelengths and switching portion for switching output from the trans-impedance type amplifier according to each of the wavelengths.Type: GrantFiled: June 12, 2003Date of Patent: February 21, 2006Assignee: Sharp Kabushiki KaishaInventors: Takanori Okuda, Masaya Ohnishi
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Patent number: 6999388Abstract: An optical disk apparatus capable of adjusting a focus servo and the like by precisely detecting a jitter amount. Light reflected from an optical disk is converted into an RF signal in an optical pickup and amplified by an RF amplifier before being supplied to an equalizer. The boost amount of the equalizer is set to zero during adjustment and set to a predetermined finite value (e.g., +20 dB) during normal recording and reproducing. By first setting the boost amount to zero, the delay characteristics of the RF signal from 3T to 11T are flattened such that an accurate jitter amount can be determined based on the integrated value of the phase differences of 3T to 11T, thereby allowing the optical pickup to be adjusted so as to minimize the jitter amount.Type: GrantFiled: April 24, 2002Date of Patent: February 14, 2006Assignee: TEAC CorporationInventors: Akira Mashimo, Chisato Takayama, Keishi Ueno
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Patent number: 6996038Abstract: In an optical disc apparatus for reading data from an optical disc, levels of photo-detecting signals outputted from a plurality of photo-detecting areas of a photo-detector are adjusted to be substantially even for canceling error components due to positioning error of the photo-detector on an optical pickup. Analogous signals outputted from the photo-detecting areas of the photo-detector are amplified by amplifiers and converted to digital signals by A/D converters. A processor takes the converted digital signals and adjusts gains of the amplifiers with using the digital signals.Type: GrantFiled: January 13, 2004Date of Patent: February 7, 2006Assignee: Funai Electric Co., Ltd.Inventor: Yasunori Kuwayama
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Patent number: 6992955Abstract: At a timing when a spot M of a main beam enters a defective area N of an optical disc, the tracking servo control is stopped, and the position the spot M of the main beam is held to the current position with respect to a radial direction of the optical disc, and, after a spot S2 of a rear sub-beam then exits the defective area N, the tracking servo control is resumed.Type: GrantFiled: July 16, 2002Date of Patent: January 31, 2006Assignee: Funai Electric Co., LtdInventor: Takayuki Ono
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Patent number: 6985413Abstract: An optical storage system includes a pickup head for picking up data from a storage medium. Firstly, the maxima of a tracking error signal and runout are obtained in a calibration procedure in a close loop formed by an optical pickup head, a pre-amplifier, a compensator, a band-pass filter and a maximum detector. A calibration factor is then defined and derived by using the obtained maxima and nominal factors of a power amplifier and the optical pickup head of the optical storage system. The path formed by the series-connected band-pass filter and maximum detector is then disabled, while the calculated calibration factor is then stored in the compensator. The optical storage system may operate in a close loop formed by the optical pick head, pre-amplifier, compensator, a power amplifier under a normal operation procedure so that the optical storage system may record or read data onto/from an optical disc under the compensation provided by the calibration factor.Type: GrantFiled: April 1, 2003Date of Patent: January 10, 2006Assignee: Via Technologies, Inc.Inventor: Meng-Huang Chu
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Patent number: 6985412Abstract: Two sum output signals from two sets of the photodetector elements located symmetrically each other with respect to a light-receiving center of the photodetector of the optical pickup are amplified individually by two amplifiers. A focus error signal is generated in accordance with a difference between respective output levels of the two amplified signals. The gains of the two amplifiers are adjusted in accordance with the focus error signal. A predetermined bias voltage is applied to the focus error signal line in the focus servo control means in accordance with the focus error signal.Type: GrantFiled: May 16, 2000Date of Patent: January 10, 2006Assignee: Pioneer CorporationInventors: Alex Bradshaw, Yuichi Kimikawa, Shinichi Naohara, Norio Matsuda
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Patent number: 6982935Abstract: A method and apparatus for suspending the operation of a rotating optical media player that uses simplified and efficient logic circuitry is described. When an operator initiates a pause operation, for example, by pressing a pause key, the current location of an optical pickup (e.g., a value of the current track ID) is stored. Then, a tracking servo loop is opened and a near zero offset is provided to the input of the tracking actuator. The condition of the optical disk system is then maintained in a “wait” state until the operator decides to end the pause process by selecting an alternate operation, such as “Play”, “Search”, or some other functions. When an alternate operation is received, the tracking servo loop is closed. The system then enters a search mode to reposition the optical head to the position indicated by the track ID, which was previously saved. Finally, the selected function command is activated.Type: GrantFiled: February 1, 2002Date of Patent: January 3, 2006Assignee: Discovision AssociatesInventor: Ludwig Ceshkovsky
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Patent number: 6977873Abstract: A system and method for dynamically re-calibrating an optical disc drive during operation is provided. The optical media includes a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten. The system can attempt several increasing levels of effort to recalibrate the disc drive until the disc drive reaches a desired level of performance, or the recalibration effort levels are exhausted. During each level of recalibration effort, various calibration values are determined for the optical media and the servo actuator, along with a notch frequency for a notch filter; a focus actuator offset; a tracking actuator offset; a focus control loop gain; and a tracking control loop gain. The optical media disc is divided into zones, and zone calibration tables for each of the zones are generated. Each zone is recalibrated using the corresponding zone calibration table.Type: GrantFiled: September 10, 2001Date of Patent: December 20, 2005Assignee: DPHI Acquisitions, Inc.Inventors: Christopher J. Turner, Charles R. Watt, Ron J. Kadlec, Hans B. Wach
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Patent number: 6970403Abstract: A calibration for a tracking error signal offset in a tracking servo system of an optical disk drive is presented. In some embodiments, the tracking error signal offset is adjusted for best servo function by, for example, adjusting the center of a tracking error signal when the tracking servo system is open to zero. In some embodiments, the tracking error signal offset is adjusted for best read function by, for example, adjusting the tracking error signal offset until the data jitter is minimized. Data jitter can be determined by reading data from the optical media and measuring the data error rate.Type: GrantFiled: September 10, 2001Date of Patent: November 29, 2005Assignee: DPHI Acquisition, Inc.Inventors: Ron J. Kadlec, Charles R. Watt, Hans B. Wach
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Patent number: 6970404Abstract: An information recording/reproducing apparatus includes a focusing optical system for focusing light from a light source on an information recording medium as a light spot and an error signal generation system for generating an error signal that represents the positional deviation between an information track and the light spot on the information recording medium from the light reflected by the information recording medium. The apparatus further includes a tilt measurement system for measuring the amount of relative inclination between the focusing optical system and the information recording medium and an offset application system for performing off-track of the light spot by applying an electric offset corresponding to the measured amount of inclination to the error signal.Type: GrantFiled: October 5, 2001Date of Patent: November 29, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Fumitomo Yamasaki, Hideki Aikoh, Akihiro Arai, Tohru Nakamura
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Patent number: 6965547Abstract: A digital servo system of an optical disk drive with a calibrated inverse non-linearity function is disclosed. A look-up table is determined, for example, with a focus error signal gain corresponding with a focus error signal offset so that the response of the focus servo system is substantially linear. Additionally, the look-up table can include tracking error signal gain, tracking error signal offset, or tracking loop gain parameters corresponding with the focus error signal offset.Type: GrantFiled: September 10, 2001Date of Patent: November 15, 2005Assignee: DPHI Acquisitions, Inc.Inventors: Ron J. Kadlec, Christopher J. Turner, Hans B. Wach
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Patent number: 6952382Abstract: A recording and reproduction apparatus for a recording medium including a plurality of information layers includes a focusing signal generation section for generating focusing signals F+ and F? in accordance with a light beam reflected by the recording medium; a focusing control section for generating a focusing error signal in accordance with a difference between the focusing signals F+ and F?, and performing focusing control for maintaining a distance between a focal point of the light beam and a target information layer within a prescribed tolerable range; and a gain setting section for setting a focusing servo gain in accordance with the focusing error signal. The focusing signal generation section generates the focusing signals F+ F? so that values of components thereof based on the light beam reflected by an information layer other than the target information layer are substantially equal while focusing control is being performed.Type: GrantFiled: April 3, 2002Date of Patent: October 4, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventor: Kenichi Nishiuchi
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Patent number: 6947359Abstract: A disk physical strain correction signal generator outputs a signal obtained by allowing a phase compensation signal to pass a LPF as a disk physical strain correction signal during a normal period. During a defect detection period, it outputs the output signal of the LPF sampled at the time of the defect detection start as the disk physical strain correction signal. A disturbance pulse correction signal is output based upon a disturbance pulse obtained by subtracting the disk physical strain correction signal from the phase compensation signal. The disk physical strain correction signal and the disturbance pulse correction signal are added to output a defect compensation signal. This defect compensation signal is applied as an actuator control signal during the defect detection period. Thus, it is possible to provide an optical disk device which can carry out a stable driving control for a reproducing operation, etc.Type: GrantFiled: February 16, 2001Date of Patent: September 20, 2005Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Eiji Yokoyama, Tomoaki Ryu
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Patent number: 6940788Abstract: According to the method, the focusing servo is activated at the zero-crossing point of a focusing error signal FE immediately after the focusing error signal FE has exceeded the first threshold th1 or has dropped below the second threshold th2. The absolute value of the first threshold th1 and the second threshold th2 is reduced each time a predetermined time t is elapsed until the focusing servo is activated.Type: GrantFiled: July 26, 2002Date of Patent: September 6, 2005Assignee: Funai Electric Co., Ltd.Inventor: Minoru Hirashima
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Patent number: 6934227Abstract: To increase the vibration resistance of an optical disk device with respect to vibrations in the focus direction. More specifically, an optical disk device is provided with a multiplication means for generating a focus vibration component FC from the focus error signal FE, a multiplication means for generating a tracking vibration component TC from the tracking error signal TE, an adder for adding the focus vibration components FC and TC, and a low-pass filter for extracting the vibration component VC from the added results. Thus, the vibration component VC is extracted considering not only vibrations in the tracking direction but also vibrations in the focus direction, so that vibrations acting on the device can be more accurately detected, and vibration resistance is increased.Type: GrantFiled: August 30, 2002Date of Patent: August 23, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Yasuo Nakata, Masanori Harui
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Patent number: 6934226Abstract: The quantity of spherical aberration correction is predetermined for each recording plane of an optical disk on which focusing control is performed. Before operating the focusing control, the quantity of spherical aberration to be corrected by an aberration correcting system is set based on an output signal from an aberration correction quantity switching device that corresponds to the type of the optical disk and the recording plane to be subjected to the focusing control. This makes it possible to perform stable focusing control on each recording plane of a multi-layer optical disk with high density by using an objecting lens having a large NA after spherical aberration has been corrected properly.Type: GrantFiled: April 8, 2002Date of Patent: August 23, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Katsuhiko Yasuda, Kousei Sano, Daisuke Ogata, Yuuichi Kuze
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Patent number: 6928034Abstract: In an optical disc apparatus, a minimum jitter value is established from each jitter value measured in correspondence to a successively changed servo constant, and multiplied by a prescribed ratio so as to set a jitter threshold value. Servo constants corresponding to at least two jitter values substantially equal to the jitter threshold value is established, and an optimum servo constant is set based on this minimum of two servo constants. By doing this, it is possible to quickly and accurately detect the optimum servo constant, and achieve good servo adjustment.Type: GrantFiled: December 17, 2001Date of Patent: August 9, 2005Assignee: Sony Computer Entertainment Inc.Inventors: Hiroshi Ohtsu, Toshisada Takada, Koichiro Takahashi
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Patent number: 6925038Abstract: The present invention provides an optical disc apparatus which solves a problem that the tracking control takes off when an objective lens is displaced in the tracking direction due to its weight. In this optical disc apparatus, a spot position detector 108 generates a spot position signal which indicates a position of a light spot on a light receiving element 105, and supplies the signal to a traverse loop filter 111 and a spot position loop filter 109. A controller 115 supplies an output from the spot position loop filter 109 to a tracking actuator 104, before supplying an output from the traverse loop filter 111 to a traverse motor 113, previously moves the light spot near the center of the light receiving element 105, and starts the traverse control in a state where a value of the spot position signal at starting of the traverse control is reduced.Type: GrantFiled: February 18, 2004Date of Patent: August 2, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Yasuhito Soma, Akira Matsubara, Kazuhiko Kouno
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Patent number: 6925037Abstract: An optical disc drive includes: an optical head with an actuator and a photodetector; a tracking driver outputting a drive signal to the actuator; a first tracking error signal generator for generating a first tracking error signal based on an output signal of the photodetector; first and second lens position control sections for respectively outputting first and second lens position control signals to the tracking driver; and a selector for selectively supplying the first tracking error signal to the first or second lens position control section according to a moving velocity of the optical head during a seek operation. The first lens position control signal is obtained by extracting signal components, of which the frequencies are equal to or lower than a predetermined frequency, from the first tracking error signal. The second lens position control signal is obtained by extracting DC components of the first tracking error signal at on-track points thereof.Type: GrantFiled: March 12, 2003Date of Patent: August 2, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Takashi Kishimoto, Takeharu Yamamoto, Yoshihiro Kanda, Jun Kikuchi
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Patent number: 6922387Abstract: The present invention relates to an optical information recording medium including a disk-shaped transparent substrate and a recording layer for recording, reproducing or erasing information by irradiation of laser light, the recording layer being formed over the substrate. The recording layer of the present invention includes information tracks including groove tracks and land tracks that are formed alternately in a radial direction of the disk. The information tracks comprise information recording regions and address regions interposed between the information recording regions, the information recording regions and the address regions being arranged along the tracking direction of the laser light.Type: GrantFiled: June 20, 2003Date of Patent: July 26, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Tetsuya Akiyama, Kenichi Nishiuchi, Kenji Narumi
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Patent number: 6922380Abstract: An anti-skate algorithm in a tracking servo system of an optical disk drive is described. The anti-skate algorithm prevents skating during close of the tracking servo system by allowing the tracking servo system to close on a tracking error signal with an appropriate slope.Type: GrantFiled: September 10, 2001Date of Patent: July 26, 2005Assignee: DPHI Acquisitions, Inc.Inventors: Ron J. Kadlec, Charles R. Watt
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Patent number: 6917571Abstract: At spin-up of an optical disk 3, gain adjustment and offset adjustment are performed on a servo error signal to obtain a first gain adjustment value and a first offset adjustment value. Based on the first gain adjustment value, a CPU 11 obtains a second gain adjustment value and a second offset adjustment value at data writing on the optical disk 3, and stores them in storage 7. When the reading state of the optical disk 3 shifts to the writing operation, the CPU 11 controls a laser power switching circuit 12 to change the output from an optical pickup 1 and, simultaneously, reads the second offset adjustment value and gain adjustment value stored in the storage 7 and sets them in an offset adjustment unit 5 and a gain adjustment unit 8, respectively.Type: GrantFiled: April 13, 2001Date of Patent: July 12, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kunimasa Kusumoto, Mitsuteru Fujimoto
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Patent number: 6906986Abstract: A vibration quantity measuring apparatus and method, and a loop design method in which a vibration quantity generated in a focus and tracking loop is accurately measured to optimally design a focus and tracking loop of an optical disc drive. The vibration quantity measuring apparatus includes an error gain adjusting unit which adjusts an amplitude of a focus and tracking error which occurs where a disc rotates, so as to maintain the amplitude of the focus and tracking error constant, a loop gain adjusting unit which compares a closed loop phase of a focus and tracking loop and a predetermined reference closed loop phase, and maintains a constant gain of the focus and tracking loop to compensate for a gain difference of an actuator, and a measuring unit which calculates and outputs a vibration quantity using an error adjusted by the error gain adjusting unit and the loop gain adjusting unit, and an output of a controller which controls a focus and tracking of the disc.Type: GrantFiled: August 29, 2002Date of Patent: June 14, 2005Assignee: Samsung Electronics Co., LtdInventors: Moon-noh Lee, Won Kim, Sung-ro Go, Dong-jin Lee, Hyun-seok Yang, Hong-gul Jun
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Patent number: 6904007Abstract: A calibration of a loop gain in a digital servo system is presented. The loop gain can be calibrated measuring the response in a control signal generated by the digital servo system when the control signal is replaced by a sum of the control signal and a sinusoidal disturbance. The loop gain can be set to provide a desired gain, for example unity, between the control signal and the sinusoidal disturbance at a cross-over frequency.Type: GrantFiled: September 10, 2001Date of Patent: June 7, 2005Assignee: DPHI Acquisitions, Inc.Inventors: Ron J. Kadlec, Hans B. Wach, Charles R. Watt
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Patent number: 6901037Abstract: A device for recording and/or reproducing an optical record carrier (1), comprises an optical system for projecting a first, a second and a third optical beam at a first (11), a second (12) and a third spot (13) at the record carrier (1). The device further comprises detection elements primary position signals (D5, C, D1) which is indicative for an amount of radiation reflected by the record carrier at said thoses spots (11). The device further comprises signal processing means (34.1, . . . 34.4; 35.1, . . . 35.4) for generating a plurality of secondary position signals (S1, S2, S3, S4) in response to the primary position signals (D5, C, D1). A selection element (36) selects one of the position signals (S1, S2, D1, S3, S4) as an output signal (WRE) in response to a selection signal (SEL). The selection signal (SEL) is derived from the output signal (WRE) of the selection element (36).Type: GrantFiled: June 20, 2001Date of Patent: May 31, 2005Assignee: Koninklijke Philips Electronics N.V.Inventors: Aik Seng Yak, Wooi Liang Chin, Canniputhur Santhana Krishnan Sanjay Krishnan
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Patent number: 6898164Abstract: A close tracking algorithm for a tracking servo system is disclosed. The track crossing rate of an optical pick-up unit positioned over an optical media is determined. When the track crossing rate is below a threshold value, then a tracking servo algorithm is enabled. The tracking servo algorithm provides control signals to control an actuator arm that controls the position of the optical pick-up unit over the tracks of the optical media. In some embodiments, the track crossing rate can be determined by monitoring the zero crossings of a tracking error signal derived from optical signals measured in the optical pick-up unit.Type: GrantFiled: September 10, 2001Date of Patent: May 24, 2005Assignee: DPHI Acquisitions, Inc.Inventors: Ron J. Kadlec, Christopher J. Turner
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Patent number: 6894956Abstract: A multimode filter in an optical storage device is used for filtering an error signal and outputting a frequency signal. The multimode filter comprises a CLV and CAV mode filter and a switch. The CLV mode filter is used for filtering the error signal and extracting a narrow bandwidth signal, whereas the CAV mode filter is used for filtering the error signal and extracting a wide bandwidth signal. The switch is used for selecting either the CLV mode filter or the CAV mode filter according to the recording mode of the optical storage device.Type: GrantFiled: June 29, 2001Date of Patent: May 17, 2005Assignee: Media Tek Inc.Inventors: Chi-Mou Chao, Hung-Jen Tseng
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Patent number: 6894957Abstract: Information is extracted from a track by a pickup during rotation of an optical disk, the output of the pickup is supplied to a head amplifier to generate an information signal including disk record information and a tracking error signal, and a reading-out speed is detected from the information signal from the head amplifier. The frequency component which is near the rotation frequency of the disk within the range of the change in the reading-out speed of the information is extracted from the detected reading-out speed signal, an eccentricity signal showing a position deviation between the center point of the track of the disk and the rotation center point of the disk is output from a band-pass filter, the output of the filter is substantially added to the output of the tracking control circuit, and a tracking actuator is driven and controlled to correct a tracking error.Type: GrantFiled: June 15, 2000Date of Patent: May 17, 2005Assignee: Kabushiki Kaisha ToshibaInventor: Hiroshi Shimada
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Patent number: 6891782Abstract: Push-pull signal is created on the basis of reflected-light detection signals output from four divided light receiving elements that receive a reflection of a recording laser light beam off an optical disk. The push-pull signal is sent to a gain variation circuit. The push-pull signal is normalized by setting the gain of the gain variation circuit to a low level in response to a mark forming section of a recording signal, but to a high level in response to a blank forming section of the recording signal. Wobble detection and pre-pit detection are performed on the basis of the normalized push-pull signal.Type: GrantFiled: November 1, 2000Date of Patent: May 10, 2005Assignee: Yamaha CorporationInventors: Minoru Saito, Kazunobu Fujiwara, Kazuhiko Honda
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Patent number: 6873583Abstract: Apparatus and method of power compensation and optical device using the same. The power compensation apparatus is used to compensate a write power of the optical device. The power compensation apparatus has a signal extraction circuit, a gain setting unit, and an adder. The signal extraction circuit is used to extract a absolute value of a portion of a servo error signal over a threshold voltage. The gain setting unit is used to generate a compensation signal using a gain thereof to adjust the absolute value of the portion of the servo error signal over the threshold voltage. The adder is used to add the compensation signal into the write power.Type: GrantFiled: October 25, 2002Date of Patent: March 29, 2005Assignee: MediaTek Inc.Inventor: Ching-Ning Chiou
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Patent number: 6865143Abstract: An optically recorded information recording and/or reading apparatus which eliminates the influence of stray light occurring within an optical system. In a state or a focus state which is forcedly set to position a reading point outside the outermost periphery of a disk surface, and the signal level is adjusted in a signal combiner circuit such that a light receiving level at that time matches a desired level.Type: GrantFiled: April 1, 2002Date of Patent: March 8, 2005Assignee: Pioneer CorporationInventors: Naoharu Yanagawa, Masahiro Kato, Tatsuhiro Yone, Yuko Muramatsu, Shinji Suzuki
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Patent number: 6865142Abstract: A method and system for correcting tracking errors in an optical storage medium having multiple tracks arranged in different layers of the optical storage medium, directs a reading spot that is nominally focused on to a track in the optical storage medium, and continually moves the reading spot in axial and radial directions so as to receive a signal having an amplitude which varies according to respective offsets from the track in radial and axial directions. The received signal is used to determine a direction of a respective offset from the track in radial and axial directions, and a location of the reading spot is adjusted accordingly.Type: GrantFiled: March 13, 2002Date of Patent: March 8, 2005Assignee: Mempile Inc.Inventors: Ori Eytan, Ortal Alpert, Yair Salomon
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Patent number: 6853609Abstract: The present invention relates to loop gain adjustment of a focus/tracking servo in an optical disk apparatus, and provides an optical disk apparatus which can make the loop gain adjustment converge normally even in an optical disk in which prerecorded areas and recorded areas are mixed, and further which always has a stable servo system even when a gain is significantly varied due to changes in the disk state. When an inserted optical disk is determined to be a recordable optical disk by an optical disk type determination means 22, an optical pickup 1 is made seek a previously set area, thereby performing the loop gain adjustment. Further, when a gain is varied during the operation, a gain adjusting means 10 changes over a gain adjustment value.Type: GrantFiled: March 16, 2001Date of Patent: February 8, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kunimasa Kusumoto, Mitsuteru Fujimoto
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Patent number: 6845068Abstract: In a focus control for following a focus position of light beam to be radiated to an optical disk to an optical disk surface, the technique is for shorten the memory length in the learning controller. The learning controller is provided to a focus feedback control system and updates the memory comprised of N numbers of memory cells with a shorter sample period than a time obtained by dividing the time required for one rotation of the disk by N numbers and outputs the learning results in the memory with the shorter sample period.Type: GrantFiled: March 27, 2002Date of Patent: January 18, 2005Assignee: Fujitsu LimitedInventor: Ichiro Watanabe
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Patent number: 6836452Abstract: There is an optical pickup apparatus 200 using a semiconductor laser element 50 having a first light emission part 36 and a second light emission part 40, wherein it is constructed so that in case that the first light emission part 36 is placed in a position in which an image height does not occur and the second light emission part 40 is placed in a position in which an image height occurs, when the first light emission part 36 is driven, the same focus driving currents are supplied from a focus driving part 120 and when the second light emission part 40 is driven, an objective lens 54b is driven in a focus direction with the objective lens inclined by generating an offset value having a predetermined value from an offset generation part 126 and varying one of the focus driving currents of the focus driving part 120.Type: GrantFiled: July 3, 2001Date of Patent: December 28, 2004Assignee: Pioneer CorporationInventor: Takehiro Matsuda
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Publication number: 20040257929Abstract: An optical disk device includes a head including an actuator that supports and moves an objective lens at least in a direction of focusing, and a slider for transporting the head in the direction of tracking. In response to a static acceleration acting on the objective lens in response to a change in the posture of the optical disk device, and a low-frequency component of a tracking servo signal for causing the objective lens to track, a slider controller drives the slider so that the objective lens is aligned with the center of an optical field of view of the head. In this arrangement, the slider is controlled with reference to the low-frequency component of the tracking servo signal corrected in accordance with the level of gravity acting on the objective lens. Slider control is thus achieved to prevent a displacement, between the objective lens and the center of the optical field of view, caused by a change in the posture of the optical disk device.Type: ApplicationFiled: April 13, 2004Publication date: December 23, 2004Applicant: Sony CorporationInventor: Yuichi Suzuki
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Patent number: 6834029Abstract: In a focusing servo apparatus for an optical pickup, an S-shaped wave of a focus error signal is measured at a point of time T1 to thereby calculate the time &Dgr;t1 required for shifting the position on the S-shaped wave from a local maximum value to a local minimum value. The speed of a lens relative to an optical disk is measured on the basis of the time &agr;t1. When the relative speed of the lens is higher than the speed allowed to lead the focus in, the motion of the lens is braked just before (a point of time T1′) the optical disk makes one rotation to thereby reduce the relative speed of the lens to make it possible to lead the focus in the optical disk steadily.Type: GrantFiled: January 2, 2002Date of Patent: December 21, 2004Assignee: Funai Electric Co., Ltd.Inventor: Minoru Hirashima
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Publication number: 20040252600Abstract: A tracking error detection device for an optical disk apparatus comprises a detecting unit which includes at least two detectors and detects a reflected light from a series of pits formed on an optical disk, a phase comparing unit which detects a phase difference of outputs of the at least two detectors, and a low-pass filter which smoothes an output of the phase comparing unit, a cut-off frequency of the low-pass filter being higher than a frequency at which a spectrum of a modulation code recorded in the optical disk becomes −10 dB and lower than a frequency at which the spectrum of the modulation code recorded in the optical disk becomes −5 dB.Type: ApplicationFiled: February 23, 2004Publication date: December 16, 2004Inventor: Shintaro Takehara
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Publication number: 20040252599Abstract: An offset adjusting circuit for an optical disc comprises an offset-adjustment differential operational amplifier having an input terminal to which an output signal of an optical pickup is input and the other input terminal to which a control voltage is applied, an A/D converter that outputs a digital signal based on an output signal of the offset-adjustment differential operational amplifier, and a control voltage adjuster that varies the control voltage applied to the offset-adjustment differential operational amplifier based on the digital signal so as to remove an offset.Type: ApplicationFiled: May 20, 2004Publication date: December 16, 2004Applicant: Sanyo Electric Co, Ltd.Inventor: Hideaki Sasaki
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Publication number: 20040246833Abstract: Track mis-registration (TMR) correction is conditionally made in a hard disk drive using servo data in a closed loop servo control scheme, along with one or more alternative sensing schemes when an external shock or vibration occurs. The alternative sensing schemes include measurement of spindle motor speed using a frequency of servo markers read from a rotating disk, voice control motor (VCM) back emf, spindle motor speed back emf, and accelerometer readings. The predicted TMR resulting from the signal generated by the alternative sensing scheme(s) is simulated based upon a model of the disk drive system, and corrections are applied only if the expected TMR due to the disturbances is large enough that application of the corrections using the alternative sensing scheme would be likely to reduce the overall TMR.Type: ApplicationFiled: June 4, 2004Publication date: December 9, 2004Inventor: Richard M. Ehrlich
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Publication number: 20040240338Abstract: A method for track jumping for optical recording media exhibiting eccentricity, and to an apparatus for reading from and/or writing to optical recording media using such method is disclosed. The method for track jumping for optical recording media exhibiting eccentricity, whereby a sled and/or an actuator are moved from a start track to an end track, includes the steps of: determining the eccentricity of the optical recording medium, initiating the track jump at minimum eccentric acceleration, and completing the track jump at minimum eccentric acceleration.Type: ApplicationFiled: May 4, 2004Publication date: December 2, 2004Inventors: Eric Fani, Christian Buchler, Gerhard Reiner
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Publication number: 20040240339Abstract: A positioning control device and method in which the relative position error in tracking is reduced by using the periodicity of position shift. The positioning control device comprises a position detecting unit for measuring the relative position error between the desired position of an objective member and a moving member, an adding unit for adding a position error signal output from the position detecting unit and a delay signal, a signal delay unit for outputting the delay signal which is obtained by delaying an output of the adding unit at a period corresponding to the position shift of the objective member, a drive unit for moving a moving member, and an inputting unit for inputting the signal of the sum of the position error signal and the delay signal to the drive unit and addition-inputting the delay signal to the drive unit through a filter having a predetermined frequency characteristic in a specific frequency range.Type: ApplicationFiled: July 31, 2003Publication date: December 2, 2004Inventors: Masashi Kubota, Sigeru Shimonou, Naotoshi Iwasawa
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Publication number: 20040240348Abstract: A disk reproducing apparatus for reproducing a digital audio signal recorded on a DVD or CD has a PLL portion for outputting a synchronizing signal in synchronism with the digital audio signal. When the CD is reproduced at double speed or higher, the PLL portion increases again while seeking tracks, and restores the gain if a predetermined time has passed after the end of seek.Type: ApplicationFiled: May 17, 2004Publication date: December 2, 2004Applicant: Funai Electric Co., Ltd.Inventor: Hiroshi Mitsuda