JP2002279700A - Optical master disk exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical master disk exposure device which can realize feed of high precision. SOLUTION: A dynamic vibration reducer, a resonance frequency controlling part which can freely set the resonance frequency of the dynamic vibration reducer and a radius position indicator are provided on a base of the optical master disk exposure device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk master exposure apparatus.

[0002]

2. Description of the Related Art A manufacturing process of a master optical disc includes an exposure process. As a prior art related to an exposure apparatus mastering apparatus for exposing a groove interval between adjacent tracks with high accuracy in an exposure step, there is an invention described in Japanese Patent Application Laid-Open No. 9-190651. In the invention described in Japanese Patent Application Laid-Open No. 9-190651, a displacement sensor is provided in the radial direction of the turntable in a non-contact manner with the turntable, and the amount of shake at each rotational position of the turntable is measured in advance. Then, an average value obtained by averaging the shake amounts for each rotation angle position is stored in a memory, and the average value corresponding to each rotation angle position is subtracted from the measured shake amount at the time of exposure to output only the asynchronous shake amount. With this output value, the irradiation position of the exposure light is corrected by the adjusting means.

In the case of the above-described prior art, the optical disk master exposure apparatus can output asynchronous vibrations irrespective of the position of each rotation angle of the turntable in real time. It is possible to grasp immediately and stop the exposure operation. Further, by correcting the irradiation position of the exposure light, the feed mechanism is not affected by the asynchronous swing of the turntable.

[0004] Further, as seen in the invention described in Japanese Patent Application Laid-Open No. 10-293928, a head for irradiating light fixed to an apparatus main body via a minute moving means, and a turntable for supporting a disk master. And a moving stage on which is mounted. In this configuration, the moving stage is moved in the diameter direction of the turntable by moving means fixed to the apparatus main body, and the position of the head is corrected with respect to the moving position of the moving stage by minute moving means.

A mastering device described in Japanese Patent Application Laid-Open No. 10-261245 discloses a laser interferometer or
Equipped with a laser holo scale, it detects a slight amount of feed unevenness of the feed slider. The detected feed unevenness is optically corrected by the optical deflection of the recording laser by the acousto-optical deflector, and the minute feed unevenness of the feed slider is optically corrected. In addition, the feed slider and the recording head are integrated via a piezo actuator, and the recording head is operated by expansion and contraction of the piezo actuator, thereby correcting a slight feed unevenness of the feed slider.

Further, in the invention described in JP-A-8-329476, an exposure optical system provided on a slider focuses an exposure beam with an objective lens. Further, a piezoelectric element for finely adjusting the position of the first fine movement table to which the objective lens is attached is provided on the second fine movement table. An optical disc master is arranged at a position facing the objective lens, and a turntable for rotating the optical disc master is arranged. Then, the vibration of the slider is canceled by moving the first fine movement table in a direction opposite to the vibration direction by the same distance as the vibration of the slider.

[0007]

However, in the invention described in Japanese Patent Application Laid-Open No. Hei 9-190651, a displacement sensor is provided in a non-contact manner in the radial direction of the turntable, and the origin pulse signal of the turntable is used as a trigger. ,
The shake amount at each rotation position of the turntable is measured in advance, and an average value obtained by averaging the shake amounts at each rotation angle position is stored in a memory. At the time of exposure, the measured shake amount corresponds to each rotation angle position. The average value is subtracted, and only the asynchronous shake amount is output, and the irradiation position of the exposure light is corrected by the adjusting unit with the output value.

Usually, the cause of the asynchronous vibration is disturbance vibration due to vibration of the device components due to the transmission of the rotational vibration to the base, and the pitch accuracy of the recording groove formed on the master optical disk is determined by the relative accuracy of the turntable and the feed moving table. Therefore, even if the feed correction is performed based on the single asynchronous shake amount as described above, the correction accuracy is poor and the exposure quality is not preferable.

Japanese Patent Laid-Open Publication No. Hei 10-293928 which can detect relative asynchronous run-out between the turntable and the feed slide.
In the invention of Japanese Patent Application Laid-Open Publication No. H10-209, a laser side of a laser length meter fixed to an apparatus main body is fixed to the apparatus main body via a micro-moving means to irradiate light, and a turntable for supporting a disc master is mounted. The position of the moving stage is illuminated on the side surface of the turntable, and based on the difference between the position of the head with respect to the device body and the position of the turntable with respect to the device body, the moving position of the moving stage Is corrected.

Usually, the disk master is mounted on the turntable with an eccentricity of about several tens of μm with respect to the outer diameter, in other words, an eccentricity of about several tens of μm. Because of this, the rotating part generates whirling vibration due to the centrifugal force acting during rotation, so the laser irradiation position on the side of the turntable changes with the rotation angle, so it is not possible to accurately measure the difference in the feeding direction, and based on the signal, If the micro-movement means is operated, accurate correction operation cannot be performed, and conversely, pitch fluctuation occurs, which is not preferable in terms of exposure quality. Further, since the laser length measuring device, which is a measuring means, is very expensive, the equipment cost increases.

In the invention described in Japanese Patent Application Laid-Open No. 8-329476, disturbance vibration due to rotation of the rotating system, minute vibration of the slider due to friction drive, and feed servo due to the low mechanical resonance frequency of the feed system. A piezoelectric element for finely adjusting the position of the first fine movement table to which the objective lens is attached is provided on the second fine movement table in order to eliminate the minute vibration of the slider due to insufficient gain, and the first fine movement table is moved by the same distance as the vibration of the slider. Is moved in the direction opposite to the vibration direction to cancel the vibration of the slider. However, this is also disclosed in Japanese Patent Application Laid-Open No.
In the same manner as in the case of Japanese Patent Application Laid-Open No. 2005-115, the feed correction is performed based on the detected amount of only the feed slider, so that the correction accuracy is poor and the exposure quality is not preferable.

Further, Japanese Patent Application Laid-Open Nos. 10-293928, 10-261245, 8-32
The invention described in Japanese Patent No. 9476 discloses a structure in which a piezo actuator is attached to the tip of an optical head or an optical head housing as a mechanism for correcting a feed direction, so that the structure is complicated, assembly adjustment is difficult, and mechanical rigidity is low. Drop,
This is not preferable for control because the servo gain of the feed system cannot be set high.

An object of the present invention is to provide an optical disk master exposure apparatus which can realize high-precision feeding without the above-mentioned problems.

[0014]

[MEANS FOR SOLVING THE PROBLEMS] To solve the above-mentioned problems,
In order to achieve the above object, an optical disc master exposure apparatus according to the present invention includes an exposure optical system that irradiates a laser beam onto an optical disc master to record predetermined information, and is guided from the exposure optical system. Focusing means for focusing the exposure beam, a slider fixed to the base, mounted with the focusing means and movable in the radial direction of the optical disk master, and position detecting means for detecting the radial position of the slider. A slider controller for controlling the operation of the slider based on an output of the position detecting means, and a rotatable rotating mechanism having a master optical disc mounted opposite to the condensing means and rotatably mounted on the base. And a resonance frequency control unit capable of freely setting the resonance frequency of the dynamic vibration absorber, and a radial position indicator.

According to the first aspect of the present invention, an exposure optical system for recording predetermined information by irradiating a laser beam onto a master optical disc, and condensing an exposure beam guided from the exposure optical system. Focusing means, a slider fixed to a base, mounted with the focusing means and movable in a radial direction of the optical disc master, a position detecting means for detecting a radial position of the slider, and a position detecting means. An optical disc master exposure apparatus comprising: a slider controller that controls the operation of the slider based on an output; and a rotatable rotating mechanism that mounts an optical disc master facing the condensing means.
A dynamic vibration absorber is provided on the base, and the resonance frequency of the dynamic vibration absorber can be freely set by the resonance frequency control unit while looking at the displayed radial position.

According to a second aspect of the present invention, in the optical disc master exposing apparatus, the dynamic vibration absorber has one end fixed to the base and a support plate fixed to the base, with a vibration direction as a feed direction. At least 2 with additional mass attached to the end
It is characterized by comprising at least one hollow elastic body, an air spring formed by supplying compressed air to a hollow portion of the hollow elastic body, and a guide rod for guiding an additional mass in the vibration direction.

According to the second aspect of the present invention, one end of the dynamic vibration absorber is fixed to the base and the support plate fixed to the base, and the other end is attached to the other end, with the vibration direction as the feed direction. At least two or more hollow elastic bodies having a fixed mass, an air spring formed by supplying compressed air to a hollow portion of the hollow elastic body, and a guide rod for guiding an additional mass in a vibration direction. Can be.

According to a third aspect of the present invention, in the optical disc master exposing apparatus, the composite spring constant of the hollow elastic body and the air spring is adjusted so that the resonance frequency of the system including the additional mass is rotatable with the optical disc master mounted thereon. The rotation frequency of the rotation mechanism is set to coincide with the rotation frequency.

According to the third aspect of the present invention, the combined spring constant of the hollow elastic body and the air spring and the resonance frequency of the system consisting of the additional mass are rotatable with the optical disc master mounted thereon. The rotation frequency of the mechanism can be matched with the rotation speed.

According to a fourth aspect of the present invention, the optical disk master exposure apparatus further comprises a controller for calculating a rotational frequency at the detected position from an output signal of the position detecting means for detecting a radial position of the slider. The resonance frequency control unit sets a resonance frequency of the dynamic vibration absorber based on a calculation result output of the controller.

According to the fourth aspect of the present invention, the resonance frequency control section calculates the rotational frequency at the detected position from the output signal of the position detecting means for detecting the radial position of the slider. The resonance frequency of the dynamic vibration absorber can be set based on the result.

According to a fifth aspect of the present invention, there is provided the optical disk master exposure apparatus further comprising: a vibration amount detecting means for detecting a vibration amount in the feed direction of the additional mass; and detecting a vibration frequency from an output signal of the vibration amount detecting means. A vibration frequency detecting means for comparing the output signal of the vibration frequency detecting means with the rotational frequency calculation result of the controller to correct the set output to the resonance frequency control section.

According to the fifth aspect of the present invention, a vibration amount detecting means for detecting a vibration amount in the feed direction of the additional mass, and a vibration frequency detecting means for detecting a vibration frequency from an output signal of the vibration amount detecting means Is provided, and an output signal of the vibration frequency detecting means is compared with a rotational frequency rotational frequency calculation result of the controller to calculate and correct a set output to the resonance frequency control unit.

According to a sixth aspect of the present invention, there is provided an optical disk master exposure apparatus, further comprising: a vibration amount detecting means for detecting a radial vibration amount of the turntable or the optical disk master; and a rotational speed based on an output signal of the vibration amount detecting means. A rotation frequency detection unit that detects a rotation frequency as an analog signal and outputs a squared analog signal of the detection signal, and sets an output signal of the rotation frequency detection unit as a setting output of the resonance frequency control unit. I do.

According to the sixth aspect of the present invention, a vibration amount detecting means for detecting a radial vibration amount of a turntable or an optical disk master, and an output signal of the vibration amount detecting means converts the rotation frequency to an analog signal. Detected as
A squared analog signal of the detection signal can be used as a setting output of the resonance frequency control unit.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an optical disk master exposure apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. The present invention is not a method of compensating for relative asynchronous runout between the turntable and the feed slide,
Focusing on the fact that the cause of the asynchronous vibration is disturbance vibration caused by vibration of the device components due to the transmission of the rotational vibration to the base, the base vibration is reduced as much as possible.

(Embodiment 1) First, Embodiment 1 of the present invention will be described with reference to the side view of FIG. A vibration isolation mechanism (not shown), for example, a base 1 provided on a pneumatic servo mounter
To 8, a fixed portion of the slider 15 which floats by static pressure by compressed air supplied from the outside is fixed. Slider 1
An end of a moving plate 14 is fixed to the upper surface of the laser beam 5, and a laser light source 10, an exposure optical system 11, and a laser beam 26 guided from a folding mirror 12 provided on the upper side.
Light collecting means 13 for collecting light is fixed.

Here, the condensing means 13 is composed of, for example, a voice coil actuator equipped with an objective lens having a high numerical aperture (NA ≧ 0.9). Further, below the slider 15, there is provided a position detecting means 33 such as, for example, an optical linear encoder comprising a light receiving section 16 for measuring the position of the light condensing means 13 in the feed direction and a scale 17. Further, the condensing means 13 is provided in the concave portion of the base 18.
A rotating mechanism 36 capable of adsorbing and fixing the optical disk master 2 is fixed to the base 18 in opposition to the base 18.

The rotating mechanism 36 detects the rotation angle of the air spindle 3 and the AC synchronous motor 4 which are rotatably floated in the thrust and radial directions by the turntable 1 and compressed air supplied from the outside, and detects the rotation angle. It comprises angle detecting means 5 such as a rotary encoder. Further, a dynamic vibration absorber 37 is fixed between the concave side surface of the base 18 and the support plate 34 fixed to the base 18 so that the vibration direction thereof coincides with the feed direction of the light collector 13. .

The structure of the dynamic vibration absorber 37 is such that one end is fixed to the base 18 and the support plate 34 with the vibration direction being the feed direction,
An additional mass 6 having two fitting holes provided at the other end is fixed 2
For example, hollow elastic bodies 7a and 7b each having a bellows-shaped cross section,
Two air springs 38a, 38b formed by supplying compressed air to the hollow portions of the hollow elastic bodies 7a, 7b
And a guide rod 35 that guides in the vibration direction by a fitting hole provided in the additional mass 6. Here, a surface treatment such as Teflon (registered trademark) is applied to an outer cylindrical surface of the guide rod 35 which is a fitting surface with a fitting hole provided in the additional mass 6 so as to have a low friction coefficient. It is configured.

Further, the position detection output 31 of the position detecting means 33 is connected to the slider controller 8, and the operation output 30 of the slider controller 8 is not shown in the drawing.
5 drive unit, for example, a DC linear motor. Further, the slider controller 8 is provided with a radial position indicator 6.
1 is also connected by a position display output 60 so that the radial position can be visually confirmed.

Further, the output 32 of the angle detecting means 5 for detecting the rotation angle generally includes an A phase obtained by dividing one circumference into several thousand equal phases,
It is composed of a B-phase pulse and a Z-phase pulse generated once in one round, and is connected to the spindle controller 9. The output of the spindle controller 9 is connected to the AC synchronous motor 4. Further, the Z-phase output 28 generated once in one round of the angle detecting means 5 and taken into the spindle controller 9 is connected to the slider controller 8 for coordinating the feeding operation and the rotating operation. Further, the slider controller 8 and the spindle controller 9 are connected to outputs 27 and 29 of a controller 19 for controlling the whole.

Next, a configuration in which the resonance frequency of the dynamic vibration absorber 37 is instantaneously variable will be described. Each of the compressed air supply ports of the air springs 38a and 38b can generate a DC voltage that drives the pressure control valve 23 that can control the pressure by an electric signal and a drive circuit 22 that drives the pressure control valve 23. It is connected to a resonance frequency control unit 20 composed of a variable DC power supply 21 via an air pipe.

Assuming that the spring constant of the hollow elastic bodies 7a and 7b in the feed direction is K ₁ and the spring constant of the air springs 38a and 38b is K ₂ , the composite spring constant K is expressed by the following equation. _{K = K 1 + K 2 K} 2 = γ · (P + P a) · A 2 / V where, A: air spring effective area P: air spring pressure gauge pressure P _a: atmospheric pressure V: the air spring volume gamma: Poly Tropic index = 1.4

Assuming that the vibration amplitude is small, A ² / V ≒ is constant, so that the combined spring constant K is, as shown in FIG.
a, 38b The composite spring constant K can be changed in proportion to the internal pressure. Generally, the relationship between the set pressure and the input voltage of the pressure control valve 23 is also proportional as shown in FIG. 3, so that the relationship between the composite spring constant K and the output voltage of the variable DC power supply 21 is proportional as shown in FIG. Become a relationship.

Further, if the resonance frequency of the dynamic vibration absorber 37 determined by the additional mass 6 (m: mass of the additional mass 6) and the composite spring constant K is f, f = (K / m) ^1/2 / ( Therefore, as shown in FIG. 5, the resonance frequency of the dynamic vibration absorber 37 with respect to the output voltage of the variable DC power supply 21 can be changed in a square root function relationship. With the configuration of the dynamic vibration absorber 37 and the resonance frequency control unit 20, the resonance frequency of the dynamic vibration absorber 37 can be instantaneously changed by manually turning an output voltage adjustment volume or the like of the variable DC power supply 21 (not shown).

Further, regarding the principle of the dynamic vibration absorber, FIG.
This will be described with reference to the vibration model and the vibration characteristic diagram of FIG. In FIG. 6, M1 and M2 are a base 18 and an additional mass 6 respectively.
K1 and K2 respectively correspond to a feed direction spring constant and a combined spring constant K of a vibration isolation mechanism (not shown).
Further, the forced periodic external force F acting on M1 corresponds to a vibration transmitting force to the base 18 due to a centrifugal force when the optical disc master 2 is eccentrically mounted and the rotating mechanism 36 rotates. FIG. 6 shows the drawing in the direction of gravity. In addition,
In the vibration characteristic diagram of FIG. 7, A1 (FIG. 7A) and A2 (FIG.
(b)) represents the vibration amplitude of M1 and M2, respectively, and δst
Is expressed as follows.

Forced periodic external force F: F = Pcosωt (ω:
Δst = P / K1 (angular frequency, t: time). Also, M1 and M2 are the respective masses, and p = (K
1 / M1) ^1/2 , pa = (K2 / M2) ^1/2

FIGS. 7A and 7B show the above relationship, p = p
a, M1 / M2 = 5 is shown in the diagram. As can be seen from FIG. 7 (a), when the natural angular frequency pa of the dynamic vibration absorber is selected to be equal to the angular frequency of the forced periodic external force F, A1 = 0, and M1 is stationary even when the forced periodic force acts on M1, and M2 is stopped.
It can also be seen that the amplitude of

Next, the operation of the above configuration will be described. In the exposure of the master optical disc, C is a cooperative feed operation of the slider 15 and the rotation mechanism 36 at a constant rotation speed.
There is a CLV feed operation which is a cooperative feed operation in which the AV rotation feed drive and the linear velocity are kept constant. First, before the exposure operation, the relationship between the radial position r and the rotation frequency ft is calculated in advance for CLV driving so as to satisfy the following equation, and the relationship with the output voltage of the variable DC power supply 21 shown in FIG. The resonance frequency characteristics of the dynamic vibration absorber 37 are measured in advance. ft = v / (2 · π · r) vs = ft · pt where, v: exposure linear velocity ft: rotation frequency r: exposure radius position vs: feed velocity pt: exposure track pitch

The rotation feed operation start command outputs 27 and 29 of the controller 19 are sent out, and the optical disk master 2 suction-fixed on the turntable 1 with an eccentric core of several tens μm is provided.
Starts rotating, the entire rotating part generates whirling vibration, and a sinusoidal vibration transmitting force in the feed direction is applied to the base 18. At this time, for example, a CAV feed drive is a constant rotation and a sinusoidal vibration transmitting force of a constant frequency is applied regardless of the exposure radial position. In the case of a CLV drive, a radial position to be exposed as shown in the above equation is used. , A sinusoidal vibration transmitting force is applied, the rotational frequency of which decreases toward the outer periphery.

In the case of CAV drive, the operator sets the resonance frequency f of the dynamic vibration absorber 37 to the fixed rotation frequency while referring to the radial position indicator 61 in the case of CLV drive. If the feeding operation is performed while sequentially adjusting the frequency manually and roughly, the vibration transmission to the base 18 due to the centrifugal force when the optical disc master 2 is eccentrically mounted and the rotating mechanism 36 rotates according to the above principle. The vibration of the base 18 due to the force can be substantially eliminated, and the influence of the rotational vibration on the feed drive can be substantially eliminated.

(Embodiment 2) Next, Embodiment 2 will be described with reference to FIG. In the first embodiment, in the case of CLV driving, the operator performs the feeding operation while manually and successively roughly adjusting the resonance frequency f of the dynamic vibration absorber 37 to the rotation frequency of the rotation mechanism 36 while referring to the radial position display 61. However, in a master for a high-density optical disc such as a DVD, defects due to dust or the like generated by an operator cause a serious problem in terms of exposure quality. Therefore, a second embodiment is configured so that no worker is interposed. Here, the description of the same parts as those of the first embodiment will be omitted.

In the second embodiment, the position detection output 31 of the position detection means 33 in the radial direction is connected to both the slider controller 8 and the controller 19, and the controller 19 supplies the relation between the rotational position ft to the radial position r and the variable DC. A storage unit 64 in which the relationship between the output voltage of the power supply 21 and the resonance frequency of the dynamic vibration absorber 37 is stored in the form of a mathematical expression, and the dynamic vibration absorber 3 required at the radial position based on the radial position data
7 and a storage unit 64 for calculating the resonance frequency, and a CPU 63 for controlling the calculation unit 65. The calculation result output 39 is transmitted as digital data. The variable DC power supply 21 constituting the resonance frequency control unit 20 according to the first embodiment is connected to the resonance frequency control unit 62 in which the D / A converter 40 has been changed.

According to the configuration of the second embodiment, the required resonance frequency of the dynamic vibration absorber 37 can be automatically set at the radial position based on the radial position by the calculating section 65 provided in the controller 19, so that an operator is required to intervene. The exposure operation can be performed without the need. Here, since the controller 19 automatically sets the resonance frequency of the dynamic vibration absorber 37, the frequency setting accuracy is improved as compared with the first embodiment.

(Embodiment 3) Further, Embodiment 3 will be described with reference to FIG. In both the first and second embodiments, a strict relationship between the output voltage of the variable DC power supply 21 and the resonance frequency of the dynamic vibration absorber 37 is required. For example, fluctuations in the supplied compressed air pressure and pressure control are required. If the previously acquired characteristics deviate due to aging of a valve or the like, the above principle is deviated, and there is a problem that the exposure quality is not preferable.

In the third embodiment, the additional mass 6
A vibration amount detecting means 47, such as a capacitance type displacement sensor, is provided to detect the vibration amount of the additional mass 6 in the feed direction. The detection signal 48 of the vibration amount detecting means 47 is
2. It is connected to the input of the amplifier 42 of the vibration frequency detecting means 41 comprising a low-pass filter LPF 43, a comparator 44 for comparing with a reference voltage, an F / V converter 45, and an A / D converter 46. The digital output signal 49 detected by the vibration frequency detecting means 41 is connected to the controller 19. The vibration frequency detecting means 41
FIG. 10 shows the state of the signals of the respective elements constituting FIG.
Shown in

The output signal a of the amplifier 42 is output as a signal containing noise, and is input to the low-pass filter LPF 43 to extract only the rotation frequency component. Further, the output signal (b in the figure) of the low-pass filter LPF 43 is input to a comparator 44 that outputs a pulse in comparison with a preset reference voltage,
4 in the output signal diagram of FIG. 4 is input to the F / V converter 45 having the characteristics of FIG. 11 and is converted into an analog voltage proportional to the frequency.

The output voltage of the F / V converter 45 is input to the A / D converter 46 and converted into a digital signal. The digital output signal 49 is input to the controller 19. It is sufficient that the reference voltage used here is set within a range that does not exceed the amplitude of the signal b. However, when the optical disc master 2 is eccentrically mounted and the rotation mechanism 36 rotates, the rotational vibration due to the centrifugal force is generated. If the vibration transmission force level to the base 18 is to be minimized, a in the output signal diagram of the amplifier 42 also becomes small, so it is preferable to set the reference voltage as small as possible.

The controller 19 compares the resonance frequency data required from the calculation result with the data of the digital output signal 49 which is the actual resonance frequency of the dynamic vibration absorber 37. Is input to the resonance frequency control unit 62 as an output in which the excess or deficiency is corrected.

In the above configuration, the resonance frequency data of the dynamic vibration absorber 37 based on the output signal of the vibration amount detection means 47 is compared with the result of the rotation frequency rotation frequency calculation of the controller 19, and the setting output to the resonance frequency control unit 62 is calculated. It is possible to correct, even if the previously acquired characteristics are deviated due to, for example, fluctuations in the supplied compressed air pressure or aging of the pressure control valve, etc. A dynamic vibration absorbing effect is obtained. In the third embodiment, it is needless to say that the strict relationship between the output voltage of the variable DC power supply 21 and the resonance frequency of the dynamic vibration absorber 37 is not necessary.

(Fourth Embodiment) Further, a fourth embodiment will be described with reference to FIG. In the second and third embodiments, since an arithmetic function, a correction function, and the like are added to the controller 19, the controller 19 becomes complicated and the cost increases. In the fourth embodiment, a vibration amount detecting means 58 such as a capacitance type displacement sensor for detecting a radial vibration amount of the turntable 1 or the optical disk master 2 is provided on the base 18 via the mounting plate 59.

The output signal 57 of the vibration amount detecting means 58
Is configured to be connected to the amplifier 51 of the rotation frequency detecting means 50 including an amplifier 51, a low-pass filter LPF 52, a comparator 53, an F / V converter 54, an analog calculator 55, and a gain adjuster 66. The output signal 56 of the rotation frequency detection unit 50 is connected to the resonance frequency control unit 67 of the first embodiment in which the variable DC power supply 21 of the resonance frequency control unit 20 is omitted. The explanation of the signals from the amplifier 51 to the output of the F / V converter 54 is the same as that described for the vibration frequency detecting means 41, and will not be described here.

The analog operation unit 55 includes an F / V converter 54
It is a square function analog arithmetic unit that squares the output and outputs the result. Here, the rotational frequency of the rotating mechanism 36 is detected as an analog signal based on the output signal of the vibration amount detecting means 58 of the turntable 1 or the optical disk master 2, and the squared analog signal corresponding to the squared analog signal is obtained from the detected signal by the analog calculator 55. Is generated, and the gain adjuster 66 sends out the output signal 56 in accordance with the input voltage of the resonance frequency characteristic of the dynamic vibration absorber 37 with respect to the output voltage.

In this configuration, the rotation frequency of the rotation mechanism 36 is detected as an analog signal based on the output signal of the vibration amount detection means 58 of the optical disk master 2, and the squared analog signal corresponding to the square calculator 55 is obtained from the detected signal. Is generated and the resonance frequency of the dynamic vibration absorber 37 is automatically set. When the rotation mechanism 36 starts rotating, the resonance frequency of the dynamic vibration absorber 37 is always set in accordance with the rotation frequency.

[0056]

As described above, the first aspect of the present invention provides a dynamic vibration absorber on a base, a resonance frequency controller capable of instantly setting the resonance frequency of the dynamic vibration absorber, and a radial position display. The optical disc master is placed eccentrically, and the rotation mechanism is adjusted by the exposure operator by adjusting the resonance frequency of the dynamic vibration absorber to the rotation frequency of the rotation mechanism while referring to the radial position indicator. The base vibration due to the vibration transmitting force to the base due to the rotational vibration due to the centrifugal force at the time of rotation can be substantially eliminated, so that the feeding accuracy can be improved and the exposure quality can be improved.

According to a second aspect of the present invention, at least the dynamic vibration absorber has one end fixed to the base and the support plate fixed to the base, and the additional mass fixed to the other end, with the vibration direction as the feed direction. The invention comprises two or more hollow elastic bodies, an air spring formed by supplying compressed air to a hollow portion of the hollow elastic body, and a guide rod for guiding an additional mass in a vibration direction. Mechanical assembly adjustment and control system design are easy, and there is no mechanical involvement around the condensing means of the feed system, so the area around the condensing means can be simplified and reduced in weight, and the mechanical rigidity is improved. The servo gain of the system can be set high, the feed control accuracy can be improved, the assemblability is good, and the equipment cost can be reduced.

According to the third aspect of the present invention, the resonance frequency of the system consisting of the composite spring constant of the hollow elastic body and the air spring and the additional mass is always equal to the rotational frequency of the rotating mechanism on which the optical disk master is mounted and which is rotatable. Since they are set to match,
Eliminates base vibration caused by vibration transmission force to the base due to centrifugal force when the optical disc master is placed eccentrically and the rotation mechanism rotates, further improving feed accuracy and improving exposure quality can do.

According to a fourth aspect of the present invention, there is provided a controller for calculating a rotational frequency at that position from an output signal of a position detecting means for detecting a radial position of the slider, and outputting a calculation result of the controller. A resonance frequency control unit that sets the resonance frequency of the dynamic vibration absorber based on the vibration amount, or a vibration amount detection unit that detects the amount of vibration in the feed direction of the additional mass and a vibration frequency detection unit that detects the vibration frequency from the output signal The output signal of the vibration frequency detection means is compared with the calculation result of the rotational frequency of the controller to correct the set output to the resonance frequency control unit. Further, the amount of radial vibration of the turntable or the master optical disc is detected. The rotational frequency is detected as an analog signal from the vibration amount detecting means and its output signal,
Rotation frequency detection means for outputting a squared analog signal of the detection signal is provided, and the output signal of the rotation frequency detection means is set as a setting output of the resonance frequency control unit. Since the rotation frequency is adjusted to the rotation frequency, it is possible to eliminate defects and the like due to dust generation of the exposure worker and the like, and to improve the exposure quality.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a configuration according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a composite spring constant of the configuration according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a relationship between a set pressure and an input voltage of a pressure control valve having a configuration according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating a relationship between a combined spring constant and an output voltage of the variable DC power supply having the configuration of the first embodiment of the present invention.

FIG. 5 is a diagram showing the relationship between the output voltage of the variable DC power supply having the configuration of the first embodiment of the present invention and the resonance frequency of the dynamic vibration absorber.

FIG. 6 is a diagram for explaining a vibration model having a configuration according to the first embodiment of the present invention.

FIG. 7 is a diagram for explaining vibration characteristics of the configuration according to the first embodiment of the present invention.

FIG. 8 is a diagram illustrating a configuration of a second embodiment of the present invention.

FIG. 9 is a diagram for explaining a configuration of a third embodiment of the present invention.

FIG. 10 is a diagram illustrating a state of a signal according to a third embodiment of the present invention.

FIG. 11 is a diagram illustrating signal characteristics according to the third embodiment of the present invention.

FIG. 12 is a diagram for explaining a configuration of a fourth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 turntable 2 optical disk master 3 air spindle 4 synchronous motor 5 angle detecting means 6 additional mass 7a hollow elastic body 8 slider controller 9 spindle controller 10 laser light source 11 exposure optical system 12 mirror 13 focusing means 14 moving plate 15 slider 16 light receiving Unit 17 scale 18 base 19 controller 20 resonance frequency control unit 21 variable DC power supply 22 drive circuit 23 pressure control valve 26 laser light 27, 29 operation start command output 28 Z-phase output 30 operation output 31 position detection output 32 output 33 position detection Means 34 Support plate 35 Guide rod 36 Rotating mechanism 37 Dynamic vibration absorber 38a Air spring 39 Calculation result output 40 Converter 41 Vibration frequency detection means 42 Amplifier 44 Comparator 45 F / V converter 46 A / D converter 47 Vibration amount detection hand Stage 48 Detection signal 49 Digital output signal 50 Rotation frequency detection means 51 Amplifier 53 Comparator 54 F / V converter 55 Analog operation unit 56, 57 Output signal 58 Vibration amount detection means 59 Mounting plate 60 Position display output 61 Radial position display 62 resonance frequency control unit 64 storage unit 65 calculation unit 66 gain adjuster 67 resonance frequency control unit

Claims (6)

[Claims] 1. An exposure optical system for recording predetermined information by irradiating a laser beam onto an optical disc master, a condensing means for condensing an exposure beam guided from the exposure optical system, and fixed to a base. A slider mounted with the condensing means and movable in a radial direction of the master optical disc; a position detecting means for detecting a radial position of the slider; and controlling an operation of the slider based on an output of the position detecting means. A dynamics absorber mounted on the base, and a resonance capable of freely setting a resonance frequency of the dynamic absorber. An optical disc master disc exposure apparatus comprising a frequency control unit and a radial position indicator. 2. The dynamic vibration absorber according to claim 1, wherein one end is fixed to the base and a support plate fixed to the base, and at least two additional masses are fixed to the other end with the vibration direction as a feed direction. 2. A hollow elastic body, an air spring formed by supplying compressed air to a hollow portion of the hollow elastic body, and a guide rod for guiding an additional mass in a vibration direction. Optical disc master exposure equipment. 3. A composite spring constant of the hollow elastic body and the air spring is set to be equal to a rotational frequency of the rotating mechanism which is rotatable so that a resonance frequency of a system including the additional mass is rotatable on a master optical disc. The optical disc master disc exposure apparatus according to claim 1 or 2, wherein: 4. A controller for calculating a rotational frequency at a detection position from an output signal of the position detection means for detecting a radial position of the slider, wherein the resonance frequency control unit calculates a calculation result of the controller. 4. The optical disk master exposure apparatus according to claim 1, wherein a resonance frequency of the dynamic vibration absorber is set based on an output. 5. A vibration amount detecting means for detecting a vibration amount in the feed direction of the additional mass, and a vibration frequency detecting means for detecting a vibration frequency from an output signal of the vibration amount detecting means, 4. An optical disk master according to claim 1, wherein an output signal of said means is compared with a result of calculating a rotational frequency of said controller to correct a set output to said resonance frequency control unit. Exposure equipment. 6. A vibration amount detecting means for detecting a vibration amount in a radial direction of a turntable or an optical disk master, and a rotational frequency as an analog signal from an output signal of the vibration amount detecting means, A rotational frequency detecting means for outputting a squared analog signal is provided, and an output signal of the rotational frequency detecting means is used as a setting output of the resonance frequency control unit. Optical disc master exposure equipment.