JPH10312583A - Apparatus for polishing disk master disk for information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing apparatus, for a disk master for an information recording medium, by which the difference in a polishing amount between the inner circumference and the outer circumference of a disk master is reduced and by which the disk master can be polished satisfactorily. SOLUTION: A polishing apparatus which polishes a disk master 40 for an information recording medium is provided with a master-disk rotation means 12 on which the disk master 40 is arranged so as to be turned, with a polishing means 14 by which the disk master 40 placed on the master-disk rotation means 12 is polished by moving a polishing belt and with a control means 16. Therefore, according to a polishing position regarding the radial direction of the disk master 40 arranged on the master-disk rotation means 12, the rotational speed of the disk master 40 and the movement speed of the polishing belt are changed, and the time in which the polishing belt comes into contact with the disk master 40 is made identical even in any polishing position regarding the radial direction of the disk master 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus for polishing a master disc of an information recording medium.

[0002]

2. Description of the Related Art In recent years, disk-shaped information recording media, for example, optical disks, have become widespread. As this kind of optical disk, for example, there is a compact disk (CD) or the like, and such a disk-shaped information recording medium is made using a disk-shaped master. A well-polished glass is used for a disk master of this type. The reason for this is that the flatness and surface roughness of the master disk are very strictly controlled.

[0003] A photosensitive material, for example, a photoresist, is applied to the master disc, and a laser beam is applied to the master disc on which the photoresist is applied, so that a necessary portion is exposed. . The laser light is turned on and off in accordance with, for example, the signal system of the compact disc, so that the portion of the photoresist that has been exposed to light is exposed, so that a signal for the compact disc can be recorded. When such a master disc is completed, the master disc is subjected to a developing process, for example, so that a portion irradiated with light is melted, and thereafter, a plating process is performed based on the master disc to form one master master. Then, several mothers can be made from this master master, and several stampers can be made from this mother.

[0004] By the way, since the disk master is conventionally made of glass, a polisher has been used as a polisher for polishing the disk master because of its easiness of automation and demand for cost reduction. This polishing machine is of a type in which a polishing cloth is moved, and a disc master is polished using this type of polishing machine.

[0005]

However, this type of polishing machine has the following problems. When the disk master is polished by the polishing machine, the disk master is rotated. The difference in the inner and outer peripheral speeds of the disk master is, for example, 1%.
In the case of a master disc having a diameter of 2 cm, the difference is about three times. For this reason, the outer peripheral portion of the disk master has a difference in the polishing amount of about 2.3 times as large as the inner peripheral portion of the disk master in the measurement result.

[0006] As described above, a disk master for producing a master for copying a large amount of optical disks is mainly a glass master at present, and a photoresist is applied to the disk master to form a matrix as described above. By irradiating the master disc with a laser beam, the disc master is exposed, developed, subjected to a metallizing process, and subjected to electroplating, thereby obtaining a stamper which is a base form for forming the optical disc.

Since the surface of the disk master corresponds to the pit surface of the final product optical disk and serves as a reference surface, the specifications of a new disk master are strictly specified. This new master disc is expensive, and the disc master is usually recycled about 500 times before use. As a recycling method, a metal attached to the surface of the master disk is chemically treated in advance, and then polished with a polishing material such as cerium oxide and reused.

[0008] Recent mastering apparatuses for mastering optical disks are made on the premise that this disk master is recycled. On the other hand, an optical disk is a DVD (Digital Versatile) which is a high-density information recording disk.
Discs and the like have begun to appear in the world, and the required quality required for the disc master has been further increased.

When a conventionally used polishing machine is used, the polishing amount of the inner peripheral portion of the disc master is, for example, 0.3 μm to
At 1.0 μm / time, the outer circumference of the disk master reaches 0.8 μm to 2.0 μm / time, about 2.3 times, and when the life of the disk master is 100 times, 50 μm to 1 μm.
A difference in polishing amount between the inner and outer circumferences of 00 μm occurs.

For this reason, the laser beam has a high aperture ratio (N
In the high-density cutting machine in which the disc master is cut using the objective lens of A), an accident occurs in which the objective lens cannot be focused on the outer periphery of the disc master, and the signal is successfully transmitted to the disc master. There is a problem that cutting is not possible. Also, when a final product optical disk is made using this disk master, the groove on the outer peripheral portion of the optical disk is formed inwardly with respect to the disk surface, so that when the disk is removed from the master, the groove is damaged. As a result, the quality of the optical disk of the final product is degraded. Therefore, the above problem was solved, and the difference in the polishing amount between the inner and outer circumferences of the disc master was reduced,
It is an object of the present invention to provide an apparatus for polishing a master disc of an information recording medium which can polish a good master disc.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is a polishing apparatus for polishing a disk master of an information recording medium, comprising: a disk rotating means for arranging and rotating the disk master; By moving, the polishing means for polishing the disk master disposed on the master rotating means, and the rotational speed of the disk master and the movement of the polishing band according to the polishing position in the radial direction of the disk master disposed on the master rotating means. Control means for changing the speed and at any polishing position in the radial direction of the disc master to make the time during which the polishing band contacts the disc master the same. Is achieved.

In the present invention, when polishing the master disc of the information recording medium, the master rotating means arranges and rotates the master disc. The polishing means polishes the disk master arranged on the master rotating means by moving the polishing band. The control means changes the rotation speed of the disk master and the moving speed of the polishing band in accordance with the polishing position of the disk rotating means in the radial direction of the disk master, and changes the polishing band at any polishing position in the radial direction of the disk master. Make the same time in contact with the master disc. As a result, the difference in the amount of polishing between the inner and outer circumferences of the disk master can be reduced or eliminated, and a good disk master can be manufactured.

[0013]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention,
Although various technically preferable limits are given, the scope of the present invention is not limited to these modes unless otherwise specified in the following description.

FIGS. 1 to 3 show a preferred embodiment of a disk master disk polishing apparatus according to the present invention. 1 to 3
The polishing apparatus 10 includes a master disk rotating unit 12, a polishing unit 14, a control unit 16, a polishing liquid supply unit 18, and the like. The master rotation means 12 includes a spindle motor 20 which is a rotary actuator and a turntable 2.
2, and the turntable 22 is connected to the output shaft 24 of the spindle motor 20. When the spindle motor 20 operates according to a command from the control means 16, the turntable 22 rotates in the R direction.

The polishing means 14 has a polishing head 30, a moving member 32, a feed screw 34, and a lateral feed motor 36. The output shaft of the traverse motor 36 is attached to the feed screw 34 side, and when the traverse motor 36 is operated by a command of the control means 16, the polishing head 3 is moved together with the moving member 32.
0 moves in the X direction (left-right direction) for positioning. This X direction corresponds to the radial direction of the glass master (disk master) 40 fixed on the turntable 22.

An example of the structure of the polishing head 30 is shown in FIG. The polishing head 30 has an endless type polishing cloth (polishing band) 50 and a rotating means 52 for rotating the polishing cloth 50. The rotation moving means 52 has pulleys 54 and 56 and a motor 58, and is connected to the pulley 54 of the output shaft of the motor 58. When the motor 58 is driven by a command from the control means 16, the endless polishing cloth 50 attached to the pulley 54 and the pulley 56 rotates in the direction A, for example.

The moving member 32 shown in FIG.
It has 0. This actuator 60 can move the polishing head 30 up and down in the Z direction. When the actuator 60 operates, the polishing cloth 50 of the polishing head 30 comes into contact with the surface of the glass master 40, and when the actuator 60 operates in reverse, the polishing cloth 50 of the polishing head 30 retreats upward from the glass master 40 along the Z direction. It has become.

The polishing liquid supply unit 18 shown in FIG. 1 is connected to a polishing liquid discharge nozzle 70. When the polishing liquid supply unit 18 is operated by a command from the control means 16, the polishing liquid discharge nozzle 70 is connected to the glass master disk. 40 and the polishing head 30
Can be supplied to the vicinity of the polishing liquid. The operation of the actuator 60 described above is also performed according to a command from the control unit 16.

FIG. 3 shows the master rotating means 12 and the polishing means 1.
4, a more detailed configuration of the control means 16 in addition to the polishing liquid supply section 18 is also shown. The control means 16 includes a computer 80, a feed motor driver 82, a turntable driver 84, a position sensor 86, a position sensor 88, and the like. The position sensor 88 is a position detecting unit that detects the position of the polishing head 30 along the X direction (radial direction) of the glass master 40. The position detected by the position detection sensor 88 is a position sensor. The signal is sent to the amplifier 86, amplified, and sent to the computer 80.

The computer 80 has a position sensor 88
The position of the polishing head 30 in the glass master 40 in the radial direction detected by the drive signal D is transmitted to the feed motor driver 82 based on the signal of the polishing position in the radial direction.
S1 and the drive signal D to the turntable driver 84.
By sending S2, the rotation speed of the glass master 40 and the moving speed of the polishing cloth 50 are changed, so that the polishing cloth 50 moves the glass master 40 at any polishing position in the radial direction (X direction) of the glass master 40. The time of contact with the surface is the same. The position sensor 88 shown in FIG. 3 includes a sensor head 89 and a position scale 87 for detecting a moving position of the sensor head 89. As the position sensor 88, a commonly used position sensor can be employed.
1 moves in the X direction in FIG. 1 integrally with the polishing head 80. Therefore, the position of the sensor head 89 and the center of the polishing head 30 always coincide.

Next, the operation of the above-described master disk polishing apparatus 10 will be described with reference to FIG. The control means 16 of the polishing apparatus 10 presets data for polishing the glass master 40 in step S1. That is, the polishing start point SP and the polishing end point E in FIG. 1 and FIG.
P, values such as the initial speed of the glass master 40 at the start of polishing, the initial speed of the polishing cloth 50 in the polishing head 30 at the start, and the feed pitch of the polishing head 30 in the X direction are preset.

When the presetting of various data is completed and the calculation is performed, polishing is started. In step S2, the polishing head 30 moves to the polishing start point SP as shown in FIGS. In step S3, the polishing pad 50 of the polishing head 30 comes into contact with the surface of the glass master 40 by operating the actuator 60 of FIG. In step S4, the control means 16 starts the rotation of the turntable motor 22, and in step S5, the feed operation of the feed motor 36 is started according to a command from the control means 16.

In step S6, the computer 80 checks information from the position sensor 88 at regular intervals, and based on this information, the computer 80 calculates the number of rotations of the turntable motor 20 and the feed motor 36. Then, the computer 80 sends the drive signal DS1 to the feed motor driver 80, and
0 sends a drive signal DS2 to the turntable driver 84. In step S7, it is determined whether the polishing head 30 shown in FIGS. 1 and 2 has moved and reached the end point EP. If the end point EP has been reached, in step S8, the control means 16 36 and the turntable motor 20 are stopped.

In step S9, the actuator 60 shown in FIG. 4 is driven to raise the polishing head 30 along the Z direction to separate the polishing pad 50 from the surface of the glass master 40. In step S10, the feed motor 36 operates to move the polishing head 30 to the origin point.

Thus, the polishing head 30 polishes the glass master 40 on the turntable 22 from the inner peripheral side to the outer peripheral side with the polishing cloth 5 on the glass master 40.
Depending on the position of 0, the rotation speed of the glass master 40,
The moving speed of the polishing pad 50 is changed by the control means 16, and polishing is performed so that the line speed of the polishing pad 50 becomes high. Thereby, the time when the polishing cloth 50 is in contact with the surface of the glass master is the same on the entire surface of the glass master 40, and without impairing the advantage of the polishing cloth moving type,
In other words, without impairing the simplicity of automation and the pursuit of lower prices,
The difference between the inner and outer circumferences of the polishing amount of the glass master 40 can be minimized. That is, the moving speed of the polishing pad 50 and the rotation speed of the glass master 40 are determined by setting the moving speed of the polishing pad 50 and the rotating speed of the glass master 40 to a constant line speed based on the positional information of the polishing pad 50 for the glass master 40. By controlling with (CLV), the line speed of the polishing pad 50 is the same at any position on the glass master 40 and the contact time of the polishing pad 50 is the same.

As a result, there is no difference in the polishing amount between the inner and outer peripheral portions of the glass master 40, and the laser beam
Even when the glass master is illuminated with the objective lens and the signal is cut at a high density, an accident such that the laser beam is out of focus at the outer peripheral portion of the glass master is prevented, and It is possible to prevent skew in a product of an optical disc made from a glass master.

However, the present invention is not limited to the above embodiment. In the embodiment described above, the polishing head 30 uses a polishing cloth, but polishing paper can also be used. The polishing head 30 is moved in the radial direction of the glass master 40 using the feed screw 34. However, it is of course possible to adopt another method. Also,
Although the disk master is made of glass in the embodiment of the present invention, the disk master is not limited to this and may be made of another material such as plastic.

[0028]

According to the present invention, a good disc master can be polished by reducing the difference in the amount of polishing between the inner and outer circumferences of the disc master.

[Brief description of the drawings]

FIG. 1 is a side view showing a cross section showing a preferred embodiment of a polishing apparatus for a master disc of an information recording medium according to the present invention.

FIG. 2 is a plan view showing a part of the polishing apparatus of FIG.

FIG. 3 is a diagram showing the polishing apparatus of FIG. 1 in more detail;

FIG. 4 is a perspective view showing a polishing head of the polishing apparatus.

FIG. 5 is a diagram showing an operation example of the polishing apparatus.

DESCRIPTION OF SYMBOLS 10 ... Polishing device, 12 ... Master rotating means, 14 ... Polishing means, 16 ... Control means, 20 ... Spindle motor (rotary actuator), 22 ... Turntable, 50 ... Endless polishing cloth, 52 ... Rotary moving means.

Claims (4)

[Claims] 1. A polishing apparatus for polishing a disc master of an information recording medium, comprising: a master disc rotating means for arranging and rotating a disc master; and moving a polishing band to thereby dispose a disc master arranged on the master disc rotating means. The polishing means for polishing, and the rotational speed of the disk master and the moving speed of the polishing band are changed in accordance with the polishing position in the radial direction of the disk master placed on the master rotating means to determine which polishing in the radial direction of the disk master. Control means for making the time at which the polishing band comes into contact with the disc master at the same position at a position. 2. The apparatus according to claim 1, wherein the polishing means comprises a position detecting means for detecting a position of the disk master in the radial direction and informing the control means of the position. 3. The apparatus for polishing an information recording medium disk master according to claim 1, wherein the master disk rotating means comprises: a table on which the disk master is mounted and continuously rotated by an actuator. 4. A disc master for an information recording medium according to claim 1, wherein the disc master is made of glass, and the polishing means comprises: an endless type polishing cloth; and a rotary moving means for rotating and moving the polishing cloth. Polishing equipment.