JP4126030B2 - Optical disc master exposure system - Google Patents

Description

  The present invention relates to an apparatus for performing servo control of a machine tool or the like that performs precision machining, and more particularly to an optical disk master exposure apparatus that performs precision machining of an optical disk master.

  An apparatus for performing servo control used in a conventional optical disk master exposure apparatus of this type is configured as shown in the block diagram of FIG. In FIG. 14, 1 is a position command generation unit, 2 is a position control unit, 3 is a speed control unit, 4 is a speed detection unit that calculates a speed by differentiating a position feedback signal output from a linear encoder described later, and 5 is a current. A control unit, 6 is a power amplifier including, for example, a power amplifier circuit, 7 is a motor that drives a mechanical system, which will be described later, 8 is a linear encoder that detects the position of the mechanical system, and 9 is a machine having a rotation mechanism on the linear motion stage. It is a system.

  Further, 10 is a position command signal output from the position command generator 1, 11 is a position feedback signal indicating the position of the mechanical system output from the linear encoder 8, and 12 is a difference between the position command signal 10 and the position feedback signal 11. Is a speed command signal output from the position control unit 2, 14 is a speed feedback signal output from the speed detection unit 4, and 15 is a difference between the speed command signal 13 and the speed feedback signal 14. A speed deviation signal, 16 is a current command signal output from the speed control unit 3, and 17 is a current feedback signal indicating a current flowing through the motor 7.

  The servo control device shown in FIG. 14 is configured so that the position feedback signal 11 indicating the position of the mechanical system 9 detected by the linear encoder 8 follows the position command signal 10 output from the position command generator 1. It is the structure which performs control. Further, in order to perform this operation stably at high speed, the position controller 2 generates a speed command signal 13 based on the position deviation signal 12 between the position command signal 10 and the position feedback signal 11. Further, the speed control unit 3 outputs a current command signal 16 to the motor 7 so that the speed feedback signal 14 generated by the speed detection unit 4 based on the position feedback signal 11 follows the speed command signal 13. Yes. Then, the current control unit 5 and the power amplifier 6 control the current flowing through the motor 7 so that the current feedback signal 17 indicating the value of the current flowing through the motor 7 follows the current command signal 16.

  Patent Document 1 includes an optical head mounted on a moving stage, an optical system that irradiates light onto a disk master by a focus mechanism, and a rotating unit that rotates the optical disk master. It describes that a vibration component is detected by a measurement unit or the like, and a base on which a rotation mechanism is mounted is vibrated by a vibration exciter to cancel vibration in the moving direction of the moving stage.

  In Patent Document 2, a recording head, a feed slider for moving the head in the diameter direction of the optical disk master, and a piezo actuator are integrated, and feed unevenness of the feed slider is detected by a laser interferometer or a laser holoscale. In addition, it is described that minute feed unevenness of a feed slider is corrected by operating a head by expansion and contraction of a piezoelectric actuator.

Patent Document 3 discloses a coarse motion table connected to a slider and its position in an optical disc master exposure apparatus having an objective lens that irradiates the optical disc master with light from an exposure optical system provided on a movable slider. There is a first laser beam for detecting the first fine movement table that can move in the same direction as the slider, and a second laser beam for detecting this position variation. It is described that the vibration of the slider is detected by the second laser light, and the first fine movement table is vibrated in the opposite direction with the same amplitude as the vibration of the slider by the piezoelectric element, thereby canceling the vibration of the slider.
JP 2002-25128 A Japanese Patent Laid-Open No. 10-261245 JP-A-8-329476

  However, in the mechanical system having a rotation mechanism on the linear motion stage in the servo control device having such a configuration, measures such as lightening the rotational system, removing rotational eccentricity, and increasing the rigidity of the linear motion stage are performed. This method has a limit in processing that requires positioning accuracy on the order of nm, such as a master exposure apparatus.

  Usually, the optical disc master mounted on the turntable of the rotating mechanism has an eccentricity of about several tens of μm with respect to the center of the turntable, in other words, is mounted on the turntable in a state where the center of gravity is offset by about several tens of μm. For this reason, the turntable swings in the rotating system due to the centrifugal force that acts during rotation. This vibration propagates to the linear motion stage mechanism, causing feed fluctuations. FIG. 15 shows the whirling vibration of the rotating system measured with the linear motion stage. The rotation frequency component (the number of rotations / sec: a large wave in FIG. 15 is one rotation of the rotation system (turntable)), and if only this frequency component can be removed, stable feed stage control can be realized. The vibration disturbance applied to the linear motion stage shown in FIG. 15, for example, in CLV, this wave gradually changes from 20 Hz to 10 Hz.

  Further, in Patent Document 1, a vibration component due to the rotational force of the rotation mechanism is detected by a measurement unit or the like, and a base on which the rotation mechanism is mounted is vibrated by a vibration exciter to cancel the vibration in the moving direction of the moving stage. It is described that a servo mechanism for detection and control is formed, and a certain degree of vibration suppression effect can be obtained. Further, Patent Document 2 only corrects the feed unevenness from the result of feed unevenness detection of the feed slider, does not constitute a servo mechanism, and the correction accuracy is poor, and Patent Document 3 describes the position detection of the feed slider. There is a problem in that it requires a complicated means and a position detecting means for the optical head.

  The present invention is directed to solving the above-described problems of the prior art, and effectively suppresses the vibration of the moving stage caused by the whirling vibration of the turntable by servo control, and the optical disc master with a stable feed stage. An object of the present invention is to provide an optical disk master exposure apparatus having a servo control device capable of maintaining a relative positional relationship with an optical head with high accuracy.

  In order to achieve this object, an optical disc master exposure apparatus according to claim 1 of the present invention includes a rotating mechanism for rotating the optical disc master, first positioning means for positioning the optical head by a moving stage mechanism, Second positioning means for positioning the optical head by a fine movement mechanism mounted on the moving stage mechanism, position detecting means for the optical head, speed detecting means for detecting the speed of the optical head, and a position command signal input from the outside Deviation detection means for detecting a deviation signal from the position detection means, position control means for generating a speed command signal from the deviation detection means, speed control means for generating a current command signal from the speed command signal and the speed detection means of the optical head, In the optical disk master exposure apparatus having the above, the rotational frequency of the rotating mechanism is set between the deviation detecting means and the first and second positioning means. There are two systems of compensation means, a local attenuation compensation means having a peak attenuation and a local peak compensation means having a peak gain at the same frequency as the rotation frequency, and positioning is performed by the first positioning means via the local attenuation compensation means. The configuration in which the positioning by the second positioning means is performed via the local peak compensation means can suppress the vibration of the moving stage and maintain the relative positional relationship between the optical disk master and the optical head.

  An optical disk master exposure apparatus according to claims 2 and 3 is the optical disk master exposure apparatus according to claim 1, wherein the local attenuation compensation means is a notch filter, and the local peak compensation means is a positive feedback of a bandpass filter. It is configured by a feedback circuit, or the local attenuation compensation means is a notch filter, and the local peak compensation means is a negative feedback feedback circuit combining a first gain element and a notch filter that are multiplied by a predetermined value, and a first multiplication that is multiplied by a predetermined value. By configuring with two gain elements, it is possible to separate and suppress vibration disturbance signals with a simple circuit configuration.

  The optical disk master exposure apparatus according to claims 4 and 5 is the optical disk master exposure apparatus according to claim 1, wherein local attenuation compensation means having a peak attenuation at a predetermined frequency, and a peak gain at the same frequency as the predetermined frequency. Two types of compensation means, including local peak compensation means, are arranged by arranging a plurality of local attenuation compensation means having peak attenuation side by side in the rotational frequency range of the rotation mechanism for rotating the optical disc master, and peaking at the same frequency as the local attenuation compensation means. Two systems of compensation: a plurality of local peak compensation means having gains arranged side by side, or a local attenuation compensation means having a peak attenuation at a predetermined frequency and a local peak compensation means having a peak gain at the same frequency as the predetermined frequency The means is configured to change the predetermined frequency according to the rotation frequency of the rotation mechanism that rotates the optical disc master, and the rotation frequency. Be varied is the frequency variation of the oscillation disturbance by variation to follow the position command signal.

  The optical disk master exposure apparatus of the present invention maintains the relative positional relationship between the optical disk master and the optical head, which is stable with high accuracy by suppressing the vibration of the moving stage, and also separates this vibration disturbance with a simple circuit configuration to improve efficiency. Even if the frequency fluctuation of the vibration disturbance fluctuates due to the fluctuation of the rotation frequency, the position command signal can be tracked.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of a mechanical system of an optical disc master exposure apparatus that uses a servo control device according to an embodiment of the present invention. As shown in FIG. 1, the optical disk master exposure apparatus is an apparatus attached to a base 34 on a vibration isolation mechanism (for example, a pneumatic servo mounter) (not shown). A fixed stage 27a is fixed on the base 34, and the moving stage 27b floats statically from the fixed stage 27a by compressed air supplied from the outside. From the light source of the Ar laser 24 on the moving stage 27b. A moving optical system 35 that guides the laser light to the optical head 36 is mounted. The moving stage 27b is moved left and right by a ball screw 28a driven by a slide motor 28. The optical head 36 is attached to the end of the moving stage 27b via a piezoelectric element 37 and can be finely moved in the same direction as the moving stage 27b. A reflection mirror 32 a is provided on the side of the optical head 36, and the position of the optical head 36 can be measured by reflecting the laser beam from the laser length measuring device 32 b on the base 34.

  A rotation mechanism is provided below the optical head 36. The rotation mechanism includes a turntable 22, an air spindle 21a that can be rotated by static pressure levitation in a thrust direction and a radial direction by compressed air supplied from the outside, and a rotation motor. 21b and an optical rotary encoder 31 for detecting the rotation angle are provided, and are attached to the base 34 via a fixed base 34a. An optical disc master 23 to be exposed is placed on the turntable 22, and the turntable 22 is sucked with the optical disc master 23 facing the optical head 36 and rotated by the air spindle 21a.

  The optical disc master 23 is irradiated with laser light from an Ar laser 24. This laser light is light in which the light emitted from the Ar laser 24 is focused to a very small spot by the objective lens in the optical head 36 via the moving optical system 35. The rotary motor 21b is feedback-controlled by a spindle servo device that uses the output pulse of the rotary encoder 31. The slide motor 28 is feedback-controlled by a positioning servo device 30a using the output pulse of the laser length measuring device 32b. A command pulse signal for driving the rotary motor 21b and the slide motor 28 is output from the system control device 33. Therefore, by controlling this command pulse signal, a spiral track groove can be formed on the optical disc master 23.

  The spiral track groove forming method can be divided into CAV (Constant Angular Velocity) control and CLV (Constant Linear Velocity) control according to the generation method of the command pulse signal of the system controller 33. In the CAV control, the rotation speed of the rotary motor 21b is constant from the beginning to the end of the spiral track groove formation. In the CLV control, the rotation speed of the rotation motor 21b is the same as that of the linear motion stage shown in FIG. It changes as the position moves from r0 to r1.

  FIG. 3 is a block diagram for explaining the function of the servo control device in the optical disk master exposure apparatus of the present embodiment. Here, components having equivalent functions corresponding to the components described in FIG. 14 showing the conventional example are denoted by the same reference numerals. In FIG. 3, 10 is a position command signal of a pulse train given by the position command generator 1 from the system controller 33 (see FIG. 1). 40 calculates a deviation pulse between the position feedback signal 11 of the pulse train and the position command signal 10 from the laser length measuring device 32b (see FIG. 1), performs D / A conversion, and converts it into a position deviation signal 12 (analog signal). Deviation detector. The position deviation signal 12 from the deviation detector 40 is applied to the position controller 2 via the local attenuation compensation means 41. The position deviation signal 12 is also applied to the piezoelectric element control unit 44 via the local peak compensation means 43.

  Reference numeral 3 denotes a speed control unit, and reference numeral 4 denotes a speed detection unit that calculates the speed by differentiating the position feedback signal 11 from the laser length measuring device 32b. Reference numeral 42 denotes a first transfer function representing a mechanical system from the amplifier that drives the slide motor 28 shown in FIG. 1 to the slide motor 28, the moving stage 27b, and the optical head 36. Reference numeral 45 denotes a second transfer function of a mechanical system including the optical head 36 driven by the piezoelectric element 37 (see FIG. 1). The outputs of the first and second transfer functions 42 and 45 of the mechanical system are displacements of the optical head 36, and the displacements are added and the final position of the optical head 36 is represented by a position signal 46.

  A vibration disturbance 18 of the moving stage 27b, which is generated due to a swing vibration of the turntable 22 or the like, is added to the position signal 46 of the optical head 36. The position of the optical head 36 to which the vibration disturbance 18 is applied becomes a position feedback signal 11 detected by the laser length measuring device 32 b and is fed back to the speed detector 4 and the deviation detector 40.

  The vibration component resulting from the rotation frequency is applied to the piezoelectric element control unit 44 via the local peak compensation means 43. On the contrary, the vibration component caused by the rotation frequency is not added to the position control unit 2 via the local damping compensation means 41. Therefore, the positioning servo device is controlled so that the optical head 36 follows the signal output from the position command generator 1 even when the vibration disturbance 18 is applied.

  As Example 1 in the present embodiment, the above-described local attenuation compensation means 41 can be realized by a notch filter (hereinafter referred to as BEF). When the transfer function is expressed using the center frequency ω0 (rad / sec) and the Q value, (Equation 1) is obtained.

周波数応答をω０＝１０，Ｑ＝５として表すと図４に示す特性となる。

When the frequency response is expressed as ω0 = 10 and Q = 5, the characteristics shown in FIG. 4 are obtained.

  Further, the local peak compensation means 43 can be realized by a positive feedback feedback circuit of a band pass filter (hereinafter referred to as BPF). FIG. 5 shows a block diagram. When this transfer function is expressed using the center frequency ω 0 (rad / sec) and the Q value, (Equation 2) is obtained.

周波数応答をω０＝１０，Ｑ＝５として表すと図６に示す特性となる。

When the frequency response is expressed as ω0 = 10 and Q = 5, the characteristics shown in FIG. 6 are obtained.

  Further, as Example 2 in the present embodiment, the above-described local attenuation compensation means 41 can be realized by BEF. When the transfer function is expressed by using the center frequency ω0 (rad / sec) and the Q value, (Expression 3) is obtained.

局所ピーク補償手段４３は所定倍するゲイン要素ＧとＢＥＦとからなる負帰還の帰還回路を構成し、さらに所定倍するゲイン要素Ｇ＋１により構成できる。図７にブロック図を示す。

The local peak compensation means 43 can be constituted by a feedback circuit of a negative feedback composed of a gain element G and BEF that are multiplied by a predetermined value, and further can be constituted by a gain element G + 1 that is multiplied by a predetermined value. FIG. 7 shows a block diagram.

  The transfer function of BEF can be expressed as (Equation 4) using the center frequency ω 0 and the Q value.

局所ピーク補償手段４３の伝達関数を計算すると、（数５）であり、

When the transfer function of the local peak compensation means 43 is calculated, (Equation 5) is obtained.

Ｇを大きく選べば局所ピーク補償手段４３の伝達関数は（数６）に近似できる。

If G is selected to be large, the transfer function of the local peak compensation means 43 can be approximated to (Equation 6).

周波数応答をω０＝１０，Ｑ＝５として表すと図６に示す特性となる。

When the frequency response is expressed as ω0 = 10 and Q = 5, the characteristics shown in FIG. 6 are obtained.

  Next, Example 3 of the present embodiment will be described. In the case of the optical disc master exposure apparatus, as described above, the rotation speed of the rotary motor 21b (see FIG. 1), which is a rotation mechanism, is constant from the beginning to the end in the CAV control, and the local attenuation compensation means as described in FIG. The center frequency of 41 and the local peak compensation means 43 may be matched with the rotation frequency of the rotation mechanism. However, the number of rotations of the rotation mechanism changes with the movement of the optical head 36 in the CLV control. In that case, the local attenuation compensation means 41 and the local peak compensation means 43 may be connected in cascade to cover the rotational frequency variation range of the rotation mechanism. For example, the local attenuation compensation means 41 can be realized by cascade connection of BEFs. .

  FIG. 8 is a diagram showing an example in which (ω1, ω2, ω3) three (ω1, ω2, ω3) are connected in cascade in the local peak compensation means 43 that constitutes a feedback circuit for positive feedback of the BPF. FIG. 9 also shows a negative feedback circuit by cascading three (ω1, ω2, ω3) BEFs having different center frequencies and a gain element G that is multiplied by a predetermined frequency, and further comprising a gain element G + 1 that is multiplied by a predetermined frequency. It is a figure which shows the other example of the local peak compensation means 43. 10 and 11 are diagrams showing the frequency response characteristics of three cascaded BEFs and BPFs used for the local attenuation compensator 41 and the local peak compensator 43 configured as described above.

  Further, in Example 4 of the present embodiment, the center frequency of the local attenuation compensator 41 and the local peak compensator 43 is changed in accordance with the change in the rotation speed of the rotation mechanism. It is a method of controlling so that vibration can be removed. FIG. 12 is a diagram showing a configuration example of local peak compensation means that can vary the center frequency ω0 and the Q value. The local peak compensation means 43 is controlled by control signals V1 and V2 from the system controller 33 (see FIG. 1).

  Since the system controller 33 performs feedback control of the rotary motor 21b of the rotary mechanism using the pulses of the rotary encoder 31, the rotational speed of the rotary mechanism is read from the rotary encoder 31, and local peak compensation is performed using the control signals V1 and V2. The center frequency ω0 and Q value of the means 43 are controlled. It is constituted by a feedback circuit that positively feeds back a BPF whose center frequency ω0 and Q value are variable by the control signals V1 and V2. In FIG. 12, the transfer function of BPF is (Expression 7).

局所ピーク補償手段４３の伝達関数は（数８）となり、

The transfer function of the local peak compensation means 43 is (Equation 8),

中心周波数ω０、Ｑ値の形式で局所ピーク補償手段４３の伝達関数を表現すると（数９）となる。

When the transfer function of the local peak compensation means 43 is expressed in the form of the center frequency ω0 and the Q value, (Equation 9) is obtained.

また、（数１０）から、

From (Equation 10)

制御信号Ｖ１，Ｖ２でゲイン要素Ｇ１，Ｇ２を可変させて局所ピーク補償の中心周波数ω０及びＱ値を制御できる。

The center frequency ω0 and Q value of local peak compensation can be controlled by varying the gain elements G1 and G2 with the control signals V1 and V2.

  FIG. 13 is a diagram showing a configuration example of local peak compensation means that can vary the center frequency ω0 and the Q value in Example 5 of the present embodiment. The local peak compensation means 43 is controlled by control signals V1, V2, and V3 from the system control device 33 (see FIG. 1). Since the system control device 33 performs feedback control using the pulse signal of the rotary encoder 31 of the rotary motor 21b of the rotary mechanism, the rotational speed of the rotary mechanism is read from the rotary encoder 31, and the control signals V1, V2, and V3 are used. The center frequency ω 0 and the Q value of the local peak compensation means 43 are controlled. A feedback element of a negative feedback is constituted by a gain element that is multiplied by a predetermined value and BEF whose center frequency ω0 and Q value are variable by the control signals V1, V2, and V3, and further a gain element that is multiplied by a predetermined value G + 1. The transfer function of BEF in FIG. 13 is (Equation 11).

（数１２）となり、

(Equation 12)

中心周波数ω０、Ｑ値で表現するＢＥＦの基本形（数１３）と同じになる。

This is the same as the basic form (Equation 13) of BEF expressed by the center frequency ω0 and the Q value.

局所ピーク補償手段４３の伝達関数は（数１４）において、

The transfer function of the local peak compensator 43 is (Equation 14)

Ｇを大きく選べば局所ピーク補償手段４３の伝達関数は（数１５）に近似できる。

If G is selected to be large, the transfer function of the local peak compensation means 43 can be approximated to (Equation 15).

中心周波数ω０、Ｑ値で局所ピーク補償手段４３の伝達関数を表現すると（数１６）となる。

When the transfer function of the local peak compensation means 43 is expressed by the center frequency ω 0 and the Q value, (Equation 16) is obtained.

（数１７）から、

From (Equation 17)

制御信号Ｖ１，Ｖ２，Ｖ３でゲイン要素Ｇ１，Ｇ２，Ｇ３を可変させて局所ピーク補償手段４３の中心周波数ω０及びＱ値を制御できる。

The center frequency ω 0 and the Q value of the local peak compensation means 43 can be controlled by varying the gain elements G 1, G 2, G 3 with the control signals V 1, V 2, V 3.

  The optical disc master exposure apparatus according to the present invention maintains the relative positional relationship between the optical disc master and the optical head by suppressing the vibration of the moving stage, separates and removes vibration disturbances with a simple circuit configuration, and further reduces the rotational frequency. Even if the frequency fluctuation of the vibration disturbance fluctuates due to fluctuations, it can follow the position command signal and is useful for exposure of an optical disc master performing servo control for precision machining.

The block diagram which shows the structure of the mechanical system of the optical disk original recording exposure apparatus using the servo control apparatus in embodiment of this invention The figure which shows the rotation speed (angular frequency) of a rotary motor which changes as a slide mechanism (linear motion stage) moves to a position by CLV control. Block diagram for explaining the function of the servo control device in the optical disc master exposure apparatus in the present embodiment The local attenuation compensation means (BEF) in Example 1 of the present embodiment (a) is a gain characteristic, and (b) is a phase characteristic. The figure which shows the structure of the local peak compensation means of the present Example 1. The local peak compensation means (BPF) in Example 2 of the present embodiment (a) is a gain characteristic, and (b) is a phase characteristic. The figure which shows the structure of the local peak compensation means of the present Example 2. The figure which shows the structure which connected the BPF of three different center frequency (omega) 0 in cascade in the local peak compensation means of Example 3 in this Embodiment. The figure which shows the structure which connected the BEF of three different center frequency (omega) 0 in cascade in the local peak compensation means of the present Example 3. The frequency response characteristics of the three BEFs connected in cascade in the third embodiment, where (a) shows gain characteristics and (b) shows phase characteristics. The frequency response characteristics of the three BPFs connected in cascade according to the third embodiment, where (a) shows gain characteristics and (b) shows phase characteristics. The block diagram which shows the structure of the local peak compensation means which can vary center frequency (omega) 0 and Q value of Example 4 in this Embodiment. The block diagram which shows the structure of the local peak compensation means which can vary center frequency (omega) 0 and Q value of Example 5 in this Embodiment. Block diagram showing schematic configuration of a conventional servo controller Diagram showing the waveform of vibration disturbance applied to the linear motion stage

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Position command generation part 2 Position control part 3 Speed control part 4 Speed detection part 5 Current control part 6 Power amplifier 7 Motor 8 Linear encoder 9 Mechanical system 10 Position command signal 11 Position feedback signal 12 Position deviation signal 13 Speed command signal 14 Speed Feedback signal 15 Speed deviation signal 16 Current command signal 17 Current feedback signal 21a Air spindle 21b Rotating motor 22 Turntable 23 Optical disc master 24 Ar laser 27a Fixed stage 27b Moving stage 28 Slide motor 28a Ball screw 29 Spindle servo device 30a Positioning servo device 31 Rotary Encoder 32a Reflecting mirror 32b Laser length measuring device 33 System controller 34 Base 34a Fixed base 35 Moving optical system 36 Optical head 37 Piezoelectric element 40 Deviation detector 41 Local attenuation compensation Means 42 First transfer function 43 Local peak compensation means 44 Piezoelectric element controller 45 Second transfer function 46 Position signal

Claims (5)

A rotating mechanism for rotating the optical disc master, a first positioning means for positioning the optical head by a moving stage mechanism, a second positioning means for positioning the optical head by a fine movement mechanism mounted on the moving stage mechanism, and the optical head Position detection means, speed detection means for detecting the speed of the optical head, position command signal input from the outside, deviation detection means for detecting a deviation signal from the position detection means, and speed command from the deviation detection means In an optical disk master exposure apparatus having position control means for generating a signal, and speed control means for generating a current command signal from the speed command signal and the speed detection means of the optical head,
Between the deviation detecting means and the first and second positioning means, a local attenuation compensating means having a peak attenuation at the rotational frequency of the rotating mechanism, and a local peak compensating means having a peak gain at the same frequency as the rotational frequency. An optical disk master comprising two systems of compensation means, wherein positioning is performed by the first positioning means via the local attenuation compensation means, and positioning is performed by the second positioning means via the local peak compensation means Exposure device.   2. An optical disk master exposure apparatus according to claim 1, wherein said local attenuation compensation means is constituted by a notch filter, and said local peak compensation means is constituted by a feedback circuit of a positive feedback of a band pass filter.   The local attenuation compensation means is constituted by a notch filter, and the local peak compensation means is constituted by a negative feedback feedback circuit combining a first gain element and a notch filter that are multiplied by a predetermined value, and a second gain element that is multiplied by a predetermined value. 2. An optical disk master exposure apparatus according to claim 1, wherein   Two types of compensation means, a local attenuation compensation means having a peak attenuation at a predetermined frequency and a local peak compensation means having a peak gain at the same frequency as the predetermined frequency, have a peak in the rotational frequency range of the rotation mechanism for rotating the optical disc master. 2. An optical disc master exposure according to claim 1, wherein a plurality of local attenuation compensation means having attenuation are arranged side by side, and a plurality of local peak compensation means having a peak gain at the same frequency as the local attenuation compensation means are arranged side by side. apparatus.   Two types of compensation means, a local attenuation compensation means having a peak attenuation at a predetermined frequency and a local peak compensation means having a peak gain at the same frequency as the predetermined frequency, correspond to the rotational frequency of the rotation mechanism for rotating the optical disc master. 2. The optical disc master exposure apparatus according to claim 1, wherein the predetermined frequency is changed.

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