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71. 发明专利

JPH04364252A OPTICAL INFORMATION REPRODUCING DEVICE 失效
公开(公告)号：JPH04364252A
公开(公告)日：1992-12-16
申请号：JP13909791
申请日：1991-06-11
申请人： FUJITSU LTD
发明人： MORITSUGU MASAHARU , IZUMI HARUHIKO , TAGUCHI MASAKAZU
IPC分类号： G11B11/10 , G11B11/105
摘要： PURPOSE:To provide an optical information reproducing device which enables to detect an edge position with good accuracy from regenerative signals of different characteristics at an ID part recorded as a rugged pit column and at a data part recorded magneto-optically, in relation to a regerative signal detection system for a magneto-optical disk of a mark length recording system. CONSTITUTION:An optical information reproducing device performing the reproduction of the optical disk recorded the ID part formed information in a recessed pit column preliminarily and the data part consisting of a magnetization column formed a magnetization spot with a magneto-optical means, respectively with the mark length recording system, is provided. In the device, a differentiation detection circuit 25 which the information of the ID part is detected with variation of an optical intensity and the ID signal i obtained with a photoelectric conversion is differentiated twice and a conversion point detection of the signal is conducted and a level slice circuit 26 separating and detecting the information of the data part to the different polarized component and performing a binary detection for a data signal j obtained with the differential signal after respective photoelectric conversions at a specified level are installed and the device is constituted so.

72. 发明专利

JPH04301225A OPTICAL DISK DEVICE 失效
公开(公告)号：JPH04301225A
公开(公告)日：1992-10-23
申请号：JP6492791
申请日：1991-03-28
申请人： FUJITSU LTD
发明人： TAGUCHI MASAKAZU , MORITSUGU MASAHARU , IZUMI HARUHIKO
IPC分类号： G11B7/00 , G11B7/004 , G11B7/005 , G11B7/085 , G11B7/135
摘要： PURPOSE:To efficiently attain high-speed access in a short time in respect of an optical disk device. CONSTITUTION:The device is constituted so that plural pieces of mirrors 111, 112,... are arranged on the radial direction of an optical disk 6, and a control part 13 to move plural mirrors in conformity to an accessing position and in addition, switch and control each mirror so as to insert/avoid the prescribed mirror to/from a straight advance beam optical path 14 is provided.

73. 发明专利

JPH03263619A METHOD AND CIRCUIT FOR CALCULATING DIFFERENCE SIGNAL 失效
公开(公告)号：JPH03263619A
公开(公告)日：1991-11-25
申请号：JP6364890
申请日：1990-03-13
申请人： FUJITSU LTD
发明人： OZAWA YASUYUKI , IZUMI HARUHIKO , FUJIMAKI TORU
IPC分类号： G11B11/10 , G11B7/085 , G11B11/105 , H03M1/10
摘要： PURPOSE:To attain highly accurate calculation without need of a high resolution A/D converter by taking a difference between an output of an A/D converter and a value corresponding to a half of a full scale output of the A/D converter. CONSTITUTION:When a difference of two analog signals A, B as a normalized difference based on the sum of the analog signals, k(A-B)/(A+B) is obtained, the sum of the analog signals A, B is given to a reference terminal of an A/D converter 32, either of the analog signals A, B is given to an input terminal of the A/D converter 32 and a difference between an output of the A/D converter 32 and a value corresponding to a half of the full scale output of the A/D converter 32 is taken. Then the output of the A/D converter 32 is once D/A converted by a D/A converter 41, the result is inputted to a noninverting terminal of a differential amplifier 42, and the value corresponding to a half of the full scale output of the A/D converter 32 is inputted to an inverting terminal of the differential amplifier 42. Thus, no A/D converter with high resolution is required and an object value is simply obtained.

74. 发明专利

JPH03150783A MAGNETO-OPTICAL DISK DEVICE 失效
公开(公告)号：JPH03150783A
公开(公告)日：1991-06-27
申请号：JP28818989
申请日：1989-11-06
申请人： FUJITSU LTD
发明人： IZUMI HARUHIKO , TAGUCHI MASAKAZU , ABE FUMITAKA
IPC分类号： G11B23/50 , G11B11/10 , G11B11/105
摘要： PURPOSE:To prevent the entered dust from affecting a floating type magnetic head by providing a dust eliminating member and bending the tip of this member to the upper part to secure a contact with the upper surface of a magneto- optical disk. CONSTITUTION:A sleigh-shaped dust eliminating member 20 is adhered to a pressurizing member 21 and has its tip bent upward. Then the member 20 attracts and eliminates the dust attached to the surface of a magneto-optical disk 1. The member 20 is attached to the arms 14 and 14a which support a floating type magnetic head 10 and provided at an advanced position against the head 10 and in the revolving direction A of the disk 1. When the disk 1 is revolved toward an arrow A, the head 10 floats slightly by the function of an air current 15 together with the member 20 touching the upper surface of the disk 1. Thus the member 20 can attract and eliminate the dust entered into a cartridge and attached to the surface of the disk 1. As a result, the dust never reaches the head 10.

75. 发明专利

JPH03150060A DOUBLE BODY TYPE VOICE COIL MOTOR 失效
公开(公告)号：JPH03150060A
公开(公告)日：1991-06-26
申请号：JP28819089
申请日：1989-11-06
申请人： FUJITSU LTD
发明人： FUJIMAKI TORU , OZAWA YASUYUKI , IZUMI HARUHIKO
IPC分类号： G11B21/02 , G11B7/085 , H02K33/18
摘要： PURPOSE:To shorten the size of a carriage and to smoothly move it by surrounding a yoke member to be engaged with right and left guide rails with windings of right and left voice coils at both ends of the carriage. CONSTITUTION:Voice coils 28, 29 are mounted at both ends of a carriage 22 loaded with an optical head 23. Voice coil motors 31, 32 are formed of yoke members 24a, 24b;, 25a, 25b and permanent magnets 24c, 25c extended in the moving direction of the carriage 22. The members 24a, 25a have V-shaped grooves 14a-1, 25a-1, and are engaged with guard rails 26, 27 of circular section for guiding the carriage 22. Bearings 30 are provided between both ends of the rails 26, 27 and the carriage 22 to smoothly move the carriage 22. The coils 28, 29 surround the rails 26, 27 and the members 24a, 25a. Thus, the length L4 of the carriage 22 is shortened, the influence of unbalance of the thrusts of the voice coils is reduced to reduce in size the entirety.

76. 发明专利

JPH02244426A ACCESS CONTROL CIRCUIT OF OPTICAL DISK DEVICE 失效
公开(公告)号：JPH02244426A
公开(公告)日：1990-09-28
申请号：JP6459489
申请日：1989-03-16
申请人： FUJITSU LTD
发明人： OZAWA YASUYUKI , IZUMI HARUHIKO , MINAMI AKIRA
IPC分类号： H04N5/85 , G11B7/085 , G11B21/08
摘要： PURPOSE:To stably execute the access at a high speed by decelerating or decelerating after accelerating a moving speed of a light spot by the time programmed in advance in accordance with a detection speed from a rush speed detecting circuit, and thereafter, switching the mode to a follow-up mode. CONSTITUTION:In accordance with a detection seed from a rush speed detecting circuit 21 from immediately after a detection time point by a rush position detecting circuit 20, a pulse for decelerating or decelerating after accelerating a moving speed of a light spot is generated by the time programmed in advance and supplied to track actuators 6, 7. An acceleration/deceleration pulse generator 22 outputs the pulse programmed in advance, and thereafter, a switch 23 and a switch 24 are switched to OFF and ON, respectively, an optical disk device is switched from a moving mode to a follow-up mode (fine control), and a track error signal from a phase lead circuit 10 is supplied to a coil 7. In such a way, the access can be executed stably and at a high speed.

77. 发明专利

JPH02220231A OPTICAL DISK DEVICE 失效
公开(公告)号：JPH02220231A
公开(公告)日：1990-09-03
申请号：JP4125289
申请日：1989-02-20
申请人： FUJITSU LTD
发明人： FUJIMAKI TORU , OZAWA YASUYUKI , IZUMI HARUHIKO
IPC分类号： G11B7/085
摘要： PURPOSE:To stably support an optical head and to stably perform a head driving by arranging a fixed part face to face with a voice coil motor sandwiching a spindle and forming an optical path where the outgoing light beam from the fixed part can not be shielded. CONSTITUTION:The fixed part 2 and the voice coil 6 are arranged face to face so as to sandwich the spindle 1. Since the fixed part 2 is arranged on the side opposite to the optical head 4 so as to sandwich the spindle 1, the size of the moving coil 6 in an advance and retreat direction can become larger by lengthening a magnetic circuit 5. The fixed part 2 is fixed on the opposite side to the head 4 so as to sandwich the spindle 1 in the advance and retreat direction of the head 4 and also fixed on a chassis 12 so that the optical axis of outgoing and incident light beams may be parallel with the advance and retreat direction of the head 4 and also deviated from the spindle 1 to the other side against the circuit 5 and allowed to pass through the spindle 1 side. Thus, the optical axis from the fixed part 2 to a mirror and the optical axis between the mirror and the head 4 are not shielded by an obstruction, so that the laser light beam between the fixed part 2 and the head 4 can be smoothly transferred.

78. 发明专利

JPH02203478A VCM STRUCTURE FOR OPTICAL DISK DEVICE 失效
公开(公告)号：JPH02203478A
公开(公告)日：1990-08-13
申请号：JP2339889
申请日：1989-01-31
申请人： FUJITSU LTD
发明人： OZAWA YASUYUKI , IZUMI HARUHIKO , FUJIMAKI TORU
IPC分类号： G11B21/02 , H02K33/18
摘要： PURPOSE:To increase the coil length and to improve the efficiency of a voice coil motor VCM by adding a joint piece at a place opposite to the single radius direction of a spindle to secure the connection between an iron core of a magnetic circuit and a yoke at a position near the spindle. CONSTITUTION:A joint piece 8 is set at a place opposite to the single radius direction of a spindle 15 to secure the connection between an iron core 6 of a magnetic circuit 4 and a yoke 7 at a position near the spindle 15. Thus a coil 12 can move forward and backward between another joint piece 9 and the spindle 15. The moving range of the coil 12 is increased compared with the normal one and therefore the coil length is increased. Thus the moving range of the coil 12 can be increased up to a point close to the spindle 15. Then the coil length is increased and the efficiency is improved for a VCM (voice coil motor).

79. 发明专利

JPH02179256A SPEED DETECTOR 失效
公开(公告)号：JPH02179256A
公开(公告)日：1990-07-12
申请号：JP33302488
申请日：1988-12-27
申请人： FUJITSU LTD
发明人： FUJIMAKI TORU , OZAWA YASUYUKI , IZUMI HARUHIKO
IPC分类号： G01P3/46 , H02K11/00 , H02K33/18
摘要： PURPOSE:To miniaturize a device and to prevent it from being affected by mutual inductance by disposing a bar magnet in an array in its longitudinal direction with one of the iron cores in a closed magnetic path having parallel two iron cores, and by coupling a speed detecting coil to a voice coil. CONSTITUTION:When current flows through a voice coil 4, flux B is generated corresponding to this current. The flux density of iron cores 1a and 1b in a closed magnetic path 1 is saturated by a bar magnet 2. On that account, the flux B cannot go through the iron core and flows outside the iron core as shown by broken lines. As the interval between both coils is set so that the flux B will not interlink up with a speed detecting coil 7, mutual inductance is reduced down. By controlling the current flowing through the voice coil 4 the action as a voice coil motor VCM 3 is performed and a control speed as desired can be obtained. Since the speed detecting coil 7 moves in parallel to the voice coil 4 integrally with a coupling mechanism 9, the voltage corresponding to that speed can be obtained. As the device needs only one closed magnetic path, it can be miniaturized accordingly.

80. 发明专利

JPH02152025A TRACK ERROR DETECTING CIRCUIT FOR OPTICAL DISK DEVICE OF SAMPLE SERVO SYSTEM 失效
公开(公告)号：JPH02152025A
公开(公告)日：1990-06-12
申请号：JP30721788
申请日：1988-12-05
申请人： FUJITSU LTD
发明人： OZAWA YASUYUKI , IZUMI HARUHIKO
IPC分类号： G11B7/095
摘要： PURPOSE:To minimize an influence of the damage of wobbled pits by holding the peak and sampling and holding the output of a subtracting means only at the time of discriminating the existence of a pulse from a peak detecting circuit. CONSTITUTION:When one of a pair of wobbled pits is damaged, an output (c) of a comparator 10 is obtained only for the other normal wobbled pit because one potential of a wobbled pit reproduced signal (s) is lower than a reference potential (e), and an output pulse (p) of a monostable multivibrator 13 is obtained only for the normal wobbled pit. Since only one output pulse (p) is obtained, outputs g1 and g2 of DFFs 141 and 142 do not simultaneously go to the high level, and an output g3 of a NAND gate 15 does not go to the low level. Consequently, a sampler and holder 16 does not perform the sampling and holding operation, and the track error signal sampled and held for the normal wobbled pit preceding the damaged wobbled pit is continuously taken out.

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