• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    A magneto-optical recording apparatus provided with a magnetic field modulator (8) is revealed. The magnetic-field modulator (8) comprises a field coil (18) for generating a magnetic field and switching means (11, 12,15,16,22) for coupling at least one terminal (17) of the magnet coil (18) to a first potential point (10) at a first potential (Vp) or a second potential point (14) at a second potential (Vn) depending on the logic value of a control signal (Vs), in order to produce in the field coil an alternating current whose polarity depends on the logic value. The field coil (18) is arranged in a parallel resonant circuit (18,21). The switching means comprise means (12,16) for inhibiting, after the terminal (17) has been uncoupled from one of the potential points (10,14), decoupling to the other potential point for a time interval corresponding to half the resonant period of the resonant circuit (18,21). This magnetic-field modulator provides a very rapid reversal of the current through the field coil.
    公开号:SU1757475A3
    申请号:SU884356647
    申请日:1988-10-11
    公开日:1992-08-23
    发明作者:Леополдис Бакс Йоханнес；Кристианус Йоханнус Хувен Петрус
    申请人:Н.В.Филипс Глоэлампенфабрикен (Фирма)；
    IPC主号:
    专利说明:

    The invention relates to the field of information storage, in particular, to magneto-optical recording devices for registering an information signal on a magneto-optical medium.
    A thermomagnetic recording device is known in which it is not the laser beam that is modulated, but the magnetic flux using an excitation unit having an inductor, a capacitor and an input bus connected to the input information signal coding unit, the inductor forming a magnetic field in the laser beam affected area carrier for the purpose of modulating the magnetic flux.
    However, in order to modulate the magnetic flux, it is necessary to use an additional source of voltage in typical magneto-optical recording devices, while considerable power is dissipated on the limiting resistor. The aim of the invention is to reduce power consumption.
    To achieve this goal in a device for modulating magnetic flux during thermomagnetic recording by a laser beam. Pa, containing the inductor of the excitation unit connected by the input bus of the coding signal with the encoding unit of the input information signal, the capacitor and the voltage source, while the inductor is installed to form a magnetic field in the section of the laser beam on the magnetic recording medium, the block is additionally inserted interrupt the current containing the first and second diodes, and the excitation unit contains the first and second buffer amplifiers, the first and second keys, and the terminals of the coil ciency connected to one another through the first
     the diode, the first key and the voltage source are connected to each other through the second diode and the second key, and the first and second buffer amplifiers are connected by inputs to the input bus of the coded signal and.
    WITH
    a 2
    but

    with
    the outputs are connected to the control inputs of the first and second switches, respectively, and the capacitor is connected parallel to the inductor in a parallel oscillating circuit.
    In addition, an additional high-pass filter capacitor is inserted in the device, connected in series with a parallel oscillatory circuit from an inductor and a capacitor.
    The current interruption unit contains the third and fourth diodes, and the excitation unit contains the third and fourth buffer amplifiers, the third and fourth keys, an inverter, and the input bus of the coded signal is connected via an inverter and the third and fourth buffer amplifiers to the control inputs of the third and fourth keys, the leads of the inductor are connected to one another through a third key and a third diode, as well as through a fourth key and a fourth diode.
    FIG. 1 shows a block diagram of a magneto-optical recording device; in fig. 2-4
    -scheme of embodiments of the device for modulating magnetic flux; in fig. five
    -epenes of signals in the modulator circuit.
    The information carrier 1 (Fig. 1) rotates from a drive unit consisting of a supporting disc 2 and an engine 3. On the carrier 1 a recording layer 4 of a magneto-optical material of the usual type is provided, to which, using an optical head 5, a beam of radiation is directed, which can be a laser beam. The magneto-optical material is then heated to a temperature near the Curie point, and a magnetic field is applied to the heated section by means of the modulator 7. After cooling, the magnetization remains. Magnetic modulator 7 modulates the magnetic flux in accordance with the control signal transmitted via the input bus of the encoded signal from the input information signal encoding unit 8, which may be an EFM encoder, while the modulator 7 with inductance coil 9 represents the magnetic field excitation unit. As a result, a magnetic domain pattern representing the information signal is formed in the recording layer 4.
    One embodiment of a device for modulating a magnetic flux (modulator 7) contains (FIG. 2) serially connected output 10 of a positive potential of a voltage source, first switch 11, first diode 12, second diode 13, second switch 14 and negative potential pin 15 voltage source, while between the point of connection of the diodes and the common bus connected parallel oscillating circuit formed by the inductor 9 and capacitor 16, and the first and second buffer amplifiers 17 are connected between the input bus coded signal and the control inputs of the first and second keys 11 and 14. The capacitance of the capacitor 16 is chosen such that the period of resonance in the circuit is less than the maximum allowable switching time required to change the direction of the magnetic flux. In a device for recording a standard EFM signal, a capacitance of 1 nF with an inductance of 5 μG is suitable.
    FIG. Figure 3 shows an embodiment of a modulator when powered from a single constant voltage source. The additional capacitor 18, together with circuit 9, 16, forms a high-pass filter to eliminate the DC component.
    FIG. 4 shows a variant of the modulator
    5 of a magnetic flux fed from a single voltage source and adapted to record signals encoded with constant DC component. In this circuit, a second circuit of a third key 11a connected in series, a third diode 12a, a fourth diode 13a and a fourth key 14a are connected in series between the terminals 10 and 15 of the voltage source,
    5 Parallel circuit 9, 16 is connected between the junction points of the first, second, third and fourth diodes, i.e. to the diagonal of the resulting bridge circuit. In addition, between the input bus coded
    The 0 signal and the control inputs of the third and fourth switches 11a and 14a are connected to an inverter 19 and the third and fourth buffer amplifiers 17a. In this circuit, the high voltage that occurs when the circuit is opened is divided between the two keys, as a result of which the circuit withstands the increased voltage.
    Since the inductor of the excitation unit is installed in a parallel resonant circuit, after blocking the current path, the oscillation in the circuit will increase and the current in the coil will be sinusoidal. Then the direction of the current is changed to the opposite. After half the period of resonance (see Fig. 5), the current will reach a limiting value, the absolute value of which is almost equal to the absolute value at the moment of breaking the circuit, but the sign of the current will be opposite. Due to the fact that the coil is excited in a different way
    the flow of current at the moment when the limit value is reached, the current can be maintained at the level of said limit value. Since to maintain the current it is only necessary to compensate for the voltage drop across the active resistance of the inductor, it only needs to apply a few volts to it, which makes it possible to use a low-voltage source as the power source, which is used to power other electronic circuits.
    Formula 1 and device 1. A device for modulating magnetic flux during thermomagnetic recording by a laser beam, comprising an inductance coil of an excitation unit connected by an input bus of a coding signal to a coding unit of an input information signal, a capacitor and a voltage source, the inductance is installed with the possibility of forming a magnetic field in the area of exposure of the laser beam to a magnetic recording medium, characterized in that, in order to reduce power consumption, a direct current unit is inserted into it. ryvani current, comprising first and second diodes, and the drive unit includes first and second buffer amplifiers, the first and second switches, wherein the coil terminals
    connected to one another via the first diode, the first key and the voltage source and connected to one another via the second diode and the second key; the first and second buffer amplifiers are connected to the input bus of the coded signal and connected to the control inputs of the first and second keys, respectively, and a capacitor is connected parallel to the inductor in a parallel oscillating circuit.
    2. The device according to claim 1, that is, with the introduction of an additional high-pass filter capacitor, included
    in series with a parallel oscillating circuit of an inductor and a capacitor.
    3. The device according to claim 1, characterized in that the current interrupting unit comprises
    the third and fourth diodes, and the excitation unit the third and fourth buffer amplifiers, the third and fourth keys, the inverter, the input bus of the coded signal is connected via an inverter and the third,
    the fourth buffer amplifiers to the control inputs of the third and fourth switches, respectively; the leads of the inductance are connected to each other additionally via a third switch and a third diode, as well as through a fourth switch and a fourth diode.
    1
    FIG. B
    1757475
    / 0-J;
    F
    tQ ij tЈ
    0
    IP
    0 b
    H 0
    n
    /
    lm
    5
    权利要求:
    Claims (3)
    [1]
    Claim
    - 1, A device for modulating magnetic flux during thermomagnetic recording by a laser beam, comprising an inductor of an excitation unit coupled to an encoding signal input bus with an input information signal encoding unit, a capacitor and a voltage source 20, while the inductor is configured to form a magnetic , fields in the area where the laser beam acts on the magnetic recording medium, it is important that 25, in order to reduce power consumption, a current interruption block holding the first and second diodes, and the excitation unit contains the first and second buffer amplifiers, the first and second switches, 30 the leads of the inductor are connected to each other through the first diode, the first switch and voltage source and connected to each other through the second diode and second the key, the first and second buffer amplifiers are connected by inputs to the input bus of the encoded signal and connected by outputs to the control inputs of the first and second keys, respectively, and the capacitor is connected in parallel to the inductor in parallel flaxen oscillatory circuit.
    [2]
    2. The device according to and. 1, which is due to the fact that an additional high-pass filter capacitor is included, included
    15 in series with a parallel oscillatory circuit of an inductor and a capacitor. ''
    [3]
    3. The device according to η, 1, with the fact that the current interruption unit contains
    20 are the third and fourth diodes, and the excitation block is the third and fourth buffer amplifiers, the third and fourth keys, the inverter, while the input bus of the encoded signal is connected through the inverter and the third, 25 fourth buffer amplifiers to the control inputs of the third and fourth keys, respectively, the outputs of the coil inductances are connected to each other additionally through the third switches of the third diode, and also through the fourth switch and the fourth diode.
    Fig!
    Yu
    I 0 * 5V
    Figure 4
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    同族专利:
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    引用文献:
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    JPS63160041U|1987-04-06|1988-10-19|DE3838858A1|1988-11-17|1990-05-23|Thomson Brandt Gmbh|CIRCUIT ARRANGEMENT FOR REVERSING A MAGNETIC FIELD|
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    US5404342A|1992-01-16|1995-04-04|Sony Corporation|Magnetic head device for magneto-optical disc system and magnetic head driving circuit|
    JP2976697B2|1992-05-29|1999-11-10|松下電器産業株式会社|Modulated magnetic field generator for magneto-optical disks|
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    JP3365435B2|1993-06-23|2003-01-14|キヤノン株式会社|Magneto-optical recording device|
    WO1995022142A1|1994-02-14|1995-08-17|Philips Electronics N.V.|Method and recording device for recording signals on a record carrier|
    JP3659988B2|1994-07-14|2005-06-15|シャープ株式会社|Magneto-optical recording device|
    US6018538A|1997-06-18|2000-01-25|Lucent Technologies Inc.|High speed non-biased semiconductor laser dione driver for high speed digital communication|
    JP2001023262A|1999-07-12|2001-01-26|Fujitsu Ltd|Winding structure and driving circuit of magnetic head|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    NL8702451|1987-10-14|
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