JPH05159381A - Grinding device for reverse side face of master plate of disk - Google Patents

Abstract

PURPOSE:To grind inner and outer side of a master plate at a definite condition and to carry out finishing work for the master plate being good in durability. CONSTITUTION:The grinding device provides a turning table 5 operating for turning the master plate used for an injection molding of an optical disk, and provides grinding heads 7 and 8 sliding on the reverse side part of the master plate with an abrasive material, and the turning table 5 is regulated in its rotational velocity according to the positions of a each grinding heads 7 and 8, and makes a sliding velocity of the master plate in contact with the abrasive material to be constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc master backside polishing apparatus for flatly polishing the backside of a disc master having concaves and convexes for molding the signal recording surface of the optical disc.

[0002]

2. Description of the Related Art Conventionally, there has been proposed an optical disk having a disk-shaped disk substrate having a main surface on one side on which fine irregularities corresponding to information signals are formed. The disk substrate of this optical disk is made of a transparent synthetic resin material such as polycarbonate or polymethylmethacrylate. Then, a reflection film made of aluminum or the like is adhered to the main surface portion of the disk substrate on one side where the irregularities are formed by a means such as vapor deposition or sputtering.

In this optical disk, from the other main surface side of the disk substrate, by optical means,
The information signal can be read by detecting the state of the irregularities via the disc substrate.

For the molding of the above-mentioned disc substrate, a disc master having a concavo-convex surface portion, that is, a so-called stamper is used. This disk master is made of a metal material such as nickel and is formed into a disk shape having substantially the same diameter as the disk master. The unevenness formed on the surface of the disk master corresponds to the information signal, but the concave and the convex are opposite to those on the disk substrate.

The back surface of the disk master is a flat surface. This disk master is placed on a flat base in a molding die in an injection molding apparatus for molding the disk substrate, and the back surface is supported by the base. In the step of molding the disc substrate, the disc master is pressed against the base by the so-called injection pressure of the material forming the disc substrate.

Here, if the back surface of the disk master has unevenness, the disk master is deformed following the unevenness of the back surface, and accurate molding cannot be performed. Therefore, conventionally, the disk master has been used by polishing the back surface into what is called a mirror surface by a disk master back surface polishing device.

The disk master back surface polishing apparatus has a turntable on which the disk master is placed and which holds the disk master and rotates it. The disk master placed on the turntable is held with the back surface facing upward.

The disk master back surface polishing apparatus has a polishing member that is in sliding contact with the back surface of the disk master held on the turntable. This polishing member comprises, for example, a so-called polishing tape formed by depositing hard fine particles on a film-shaped substrate, and a supporting member for supporting the polishing tape, and the polishing surface of the polishing tape. Is supported so as to be brought into contact with the back surface of the above-mentioned disk master with a predetermined contact pressure. Further, the polishing member extends in the direction in which it comes in contact with and separates from the center of rotation of the turntable and is parallel to the back surface of the disk master held by the turntable, that is, the inner and outer circumferences of the disk master. It is supported so that it can be moved in any direction.

In this disk master backside polishing apparatus,
When the disk master is rotated while the polishing member is in contact with the back surface of the disk master, the polishing member slides on the back surface of the disk master to polish the back surface. Then, the polishing member is moved over the inner and outer circumferences of the disc master, whereby the entire back surface of the disc master is polished.

Since the polishing tape is abraded as the disc master is polished, the used tape is wound so that the unused part is slid on the disc master while being fed. The back side of the disc master is polished.

[0011]

By the way, in the above-described disk master back surface polishing apparatus, the turntable is always rotated at a substantially constant rotational angular velocity. Therefore, the sliding contact speed between the polishing member and the disc master gradually changes from the inner peripheral portion to the outer peripheral portion of the disc master.

Therefore, the polishing amount per unit time is different between the inner peripheral side and the outer peripheral side of the disc master, and the abrasion amount of the polishing tape is also different. Therefore, in this disk master back surface polishing apparatus, it is difficult to polish the disk master in a constant state over the inner and outer circumferences thereof. That is, if it is attempted to make the polishing amount constant over the inner and outer peripheries of the disc master, the polishing time must be different between the inner peripheral portion and the outer peripheral portion of the disc master, and it is difficult to finish to the same roughness. Become.

Further, in this disk master back surface polishing apparatus, since the abrasion amount of the polishing tape per unit time is different between the inner peripheral side and the outer peripheral side of the disk master, the feed rate of the polishing tape is kept constant. If so, the polishing state changes over the inner and outer peripheral sides of the disk master.

Therefore, the present invention has been proposed in view of the above-mentioned circumstances, and is a disk capable of polishing the back surface of a disk master used for molding an optical disk in a substantially constant state over the entire surface. An object is to provide a master backside polishing apparatus.

[0015]

In order to solve the above-mentioned problems and achieve the above-mentioned object, a disk master backside polishing apparatus according to the present invention has an uneven surface for forming a signal recording surface of an optical disk. A turntable for holding and rotating the disk master, a polishing member held in contact with the back surface of the disk master for rotation by the turntable, and a position of the polishing member on the disk master. Polishing position detecting means for detecting, and control means for controlling the rotation speed of the turntable based on the position on the disk master of the polishing member detected by the polishing position detecting means, the control means,
By controlling the rotation speed of the turntable,
The change in the relative sliding contact speed between the disc master and the polishing member over the inner and outer circumferences of the disc master is suppressed within a preset range.

[0016]

In the disk master back surface polishing apparatus according to the present invention, the disk of the relative sliding contact speed between the disk master for molding the optical disk and the polishing member slidably contacting the back surface of the disk master is controlled by the control means. Since the change over the inner and outer circumferences of the master disk is suppressed within a preset range, the back surface of the master disk is polished to a substantially constant state over the inner and outer circumferences of the master disk.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings. A back surface polishing apparatus for a disk master according to the present invention is a disk master used when molding a disk substrate of an optical disk by forming fine irregularities corresponding to information signals on one main surface portion of the disk substrate, that is, a so-called stamper. A device for polishing the back surface. The disk substrate is made of a transparent synthetic resin material such as polycarbonate or polymethylmethacrylate. The optical disk is constructed by depositing a reflective film made of aluminum or the like on the main surface portion of the disk substrate on one side where the unevenness is formed by means such as vapor deposition or sputtering.

The disk master is made of a metal material such as nickel and is formed into a disk shape having substantially the same diameter as the disk master. Concavities and convexities corresponding to the above information signals are formed on the surface portion of the master disc. The concave and convex portions are opposite to the concave and convex portions on the disk substrate.

Here, the manufacturing process of the disk master will be briefly described. In order to manufacture the above disc master, first, as shown in FIG. 5, a flat synthetic resin layer 102 is formed on a flat glass substrate 101. This synthetic resin layer 10
As the material forming 2, for example, an ultraviolet curable resin or the like is used. Next, as shown in FIG. 6, unevenness corresponding to the information signal is formed on the synthetic resin layer 102 by using the focused laser beam 103.

Then, a metal layer 104 is formed on the synthetic resin layer 102 on which unevenness corresponding to the information signal is formed by means such as so-called electroless plating or sputtering, and further, on this metal layer 104. The plating layer 105 is formed by means such as so-called electroforming plating. The metal layer 104 and the plating layer 105 are formed of a metal material such as nickel.

The synthetic resin layer 102, the metal layer 104, and the plating layer 10 thus formed in a laminated shape.
As shown in FIG. 8, reference numeral 5 has a boundary surface that follows the irregularities corresponding to the information signal. The depth of the irregularities shown by the arrow c in FIG. 8 is about 0.3 μm. Also,
The thickness of the metal layer 104 shown by the arrow b in FIG. 8 is about 0.
It is about 3 μm to several μm. The thickness of the plating layer 105 shown by the arrow a in FIG. 8 is about 0.3 mm.

Then, the upper surface portion 105 of the plating layer 105 is formed.
A has irregularities having a depth of about 5 to 10 μm as shown by an arrow d in FIG. This unevenness is generated in the plating process.

Next, as shown in FIG. 9, the metal layer 10 is
4 and the plating layer 105 are peeled off from the synthetic resin layer 102. Then, as shown in FIG. 10, the plating layer 1
The disc master 110 is formed by polishing the upper surface portion 105a of No. 05 with the disc master back surface polishing device according to the present invention to eliminate the above-mentioned irregularities and to make it a mirror surface. The upper surface portion 105a of the plating layer 105 is the disk master 1
It becomes the back surface of 10.

To polish the back surface of the disk master 110, the disk master 110 is rotated as indicated by an arrow R in FIG. 10, and the polishing tape 50 supported by the polishing roller 18 serving as a polishing member is removed from the back surface. It is performed by sliding on the part. The polishing tape 50 is guided and operated by the polishing roller 18 as shown by an arrow S in FIG.

In this way, the back surface of the disk master 110 is polished by precisely deforming the disk master in the mold for molding the disk substrate by following the irregularities existing on the back surface. This is because it is prevented.

This disk master 110 is placed on the flat upper surface of the lower mold 106 constituting the molding die in the injection molding apparatus for molding the above-mentioned disk substrate, and the back surface is placed under the lower surface. It is supported by the mold 106. The upper mold 107 that constitutes the above-mentioned mold is abutted on the lower mold 106. The upper die 107 and the disc master 110
A space corresponding to the thickness of the disk substrate is formed between and.

The formation of the disc substrate is performed by injecting the melted material of the disc substrate into a space between the disc master 110 and the upper die 107 through a gate 108 at a predetermined injection pressure. By doing so.

As shown in FIG. 1, the disk master back surface polishing apparatus according to the present invention has an outer casing 2. A chassis 1 is provided in a substantially central portion of the outer casing 2 so as to divide the outer casing 2 into upper and lower parts. A portion of the outer casing 2 above the chassis 1 is a door portion 3 having a front surface that can be opened and closed. Further, a control device (not shown) serving as control means is housed in a portion of the outer casing 2 below the chassis 1. This control device is configured to have an electronic circuit such as a CPU (central processing unit). An operation control unit 4 for operating the control device is provided on a front surface of a portion of the outer housing 2 below the chassis 1.

As shown in FIG. 2, the outer casing 2 has an exhaust duct 14 for keeping the inside of the outer casing 2 clean.
A water supply / drainage pipe 15 for cooling and cooling is attached.

The disk master 110 is placed on the chassis 1, and the turntable 5 for holding and rotating the disk master 110 is provided. As shown in FIG. 4, the turntable 5 has a plurality of disc master holding members 28, 28 on its outer peripheral portion. The turntable 5 has the above-mentioned respective disk master holding members 2
The disk master 110 is held by 8, 28 with the back surface facing the upper surface.

The turntable 5 corresponds to the chassis 1
It is attached to the table support portion 35 on the upper end side of the support shaft 32 which is rotatably supported with respect to and is rotatably supported with respect to the chassis 1. The support shaft 32 is supported with its axis substantially perpendicular to the chassis 1.

The support shaft 32 is supported on the chassis 1 via an outer cylinder member 27 and an inner cylinder member 34. That is, in the substantially central portion of the chassis 1,
The outer cylinder member 27 is fixed and attached so as to be fitted into the opening formed in the chassis 1.
The outer cylinder member 27 is formed in a substantially cylindrical shape, and its axis is perpendicular to the chassis 1. This outer cylinder member 2
The inner cylinder member 34, which is formed in a substantially cylindrical shape, is fitted and supported in the inside 7 through a pair of rotary bearings 37, 37. The inner cylinder member 34 has an axis of a cylindrical surface forming an outer peripheral surface aligned with the axis of the outer cylinder member 27, and is rotatable with respect to the outer cylinder member 27. .. The inner cylindrical member 34 has a belt wheel portion 38 provided on the lower end side protruding downward from the lower end portion of the outer cylindrical member 27. The belt wheel portion 38 has the inner cylinder member 34.
Is coaxial with the outer peripheral surface of the.

The cylindrical surface forming the inner peripheral portion of the inner cylindrical member 34 is eccentric to the cylindrical surface forming the outer peripheral surface of the inner cylindrical member 34 by a predetermined distance indicated by an arrow D in FIG. ..
The axis of the cylindrical surface forming the inner peripheral portion of the inner cylinder member 34 is parallel to the axis of the cylindrical surface forming the outer peripheral surface of the inner cylinder member 34. The support shaft 32 is rotatably supported in the inner tubular member 34 via a pair of rotary bearings 36, 36. That is, the support shaft 32 is indicated by an arrow R in FIG.
As shown in FIG. 5, the inner cylinder member 34 is rotatable about its axis, and when the inner cylinder member 34 is rotated with respect to the outer cylinder member 27, the axis is set to the inner cylinder member 34. The member 34 is moved on a cylindrical locus whose radius is a distance corresponding to the amount of eccentricity between the inner peripheral surface and the outer peripheral surface.

The support shaft 32 is rotated by the table motor 23 disposed on the lower side of the chassis 1 via the intermediate shaft 26. The table motor 23 is
A plurality of columns 24, 25 are provided on the lower surface of the chassis 1.
It is attached to and supported by the motor support plate 28 attached via. The table motor 23 directs the drive shaft 30 toward the upper side, which is the chassis 1 side. The lower end side of the intermediate shaft 26 is connected to the tip end side of the drive shaft 30 via a first free joint part (universal joint part) 29. The upper end of the intermediate shaft 26 is connected to the lower end of the support shaft 32 via the second free joint portion 31. That is, in the table motor 23, the support shaft 32 has the inner cylinder member 34.
Of the drive shaft 30 by rotation of the drive shaft 30 with respect to the outer cylinder member 27.
Even if the position is eccentric to the support shaft 32, the support shaft 32 can be rotated. This table motor 23 is
The rotation speed is controlled by the control device to drive the rotation.
The peripheral portion of the intermediate shaft 26 is covered with a bellows member 33 made of a synthetic resin material.

Then, the inner cylinder member 34 is moved relative to the outer cylinder member 27 by the eccentric motor 41 disposed in the lower portion of the chassis 1 via the endless drive belt 39 and the belt wheel portion 38. Is rotated. The eccentric motor 41 is fixedly disposed on the lower surface of the chassis 1 via a support member. A belt wheel 40 is attached to the drive shaft of the eccentric motor 41. Between the belt wheel 40 and the belt wheel portion 38 of the inner cylinder member 34,
The endless drive belt 39 is wound around. The eccentric motor 41 is driven to rotate by being controlled by the control device.

Then, as shown in FIGS. 1 to 3, the back surface polishing apparatus for the disk master has the above-mentioned turntable 5
For supporting the above-mentioned polishing tape 50 that serves as a polishing member for polishing the back surface of the disk master 110 held above,
It has first and second polishing heads 7 and 8. The polishing tape 50 is formed, for example, by depositing hard fine particles on a tape-shaped base material.

Each of the polishing heads 7 and 8 is a spinal column movably supported on the chassis 1 by a polishing head support plate 6 arranged at a position rearward of the turntable 5 on the chassis 1. It is configured to have a plate.
That is, the polishing head support plate 6 is formed in a substantially vertical wall shape, and a pair of support rails 19 and 20 are attached to the front surface portion facing the turntable 5. These support rails 19 and 20 are parallel to the chassis 1. The spinal plate of each of the polishing heads 7 and 8 is supported by the support rails 19 and 20 on the base end side thereof, and along the support rails 19 and 20, as shown by arrows T in FIGS. 1 and 3. In addition, it is movable on the chassis 1 in parallel with the chassis 1.

The first polishing head 7 is moved along the support rails 19 and 20 by the first head feed motor 42 attached to the polishing head support plate 6. That is, the first head feed motor 42 includes the pair of bearings 4 with respect to the polishing head support plate 6.
The first screw shaft 22 rotatably attached via 4, 45 is rotationally operated. The first screw shaft 22 is arranged parallel to the support rails 19 and 20. A first screw ring 46 attached to the base end side of the spinal plate of the first polishing head 7 is screwed onto the first screw shaft 22. When the first screw shaft 22 is rotationally operated, the first screw ring 46 is operated in the axial direction of the first screw shaft 22 together with the first polishing head 7.

On the other hand, similarly to the first polishing head 7, the second polishing head 8 is also supported by the second head feed motor 43 attached to the polishing head support plate 6 so that the support rails 19, It is moved along 20. That is, the second head feed motor 43 rotationally operates the second screw shaft 21 rotatably attached to the polishing head support plate 6 via the pair of bearings 48 and 49. This first screw shaft 21 is
The support rails 19 and 20 are arranged in parallel with each other.
A second screw ring 49 attached to the base end side of the spinal plate of the second polishing head 8 is screwed onto the second screw shaft 21. When the second screw shaft 21 is rotated, the second screw shaft 21
The screw ring 49 of the second screw is fed and operated in the axial direction of the second screw shaft 21 together with the second polishing head 8.

The head feed motors 42 and 43 described above are used.
Is a so-called stepping motor, the rotation angle amount of which is controllable and the rotation angle can be detected. In addition, these head feed motors 42,
43 is rotationally driven by controlling the rotational speed and the rotational angle amount by the control device.

The polishing heads 7 and 8 are configured to bring the polishing tape 50 into contact with the back surface of the disk master 110 on the turntable 5 with a predetermined contact pressure.

That is, on the spinal plate of the first polishing head 7, the supply reel 12 and the take-up reel 13 are provided.
And are rotatably mounted. The supply reel 12 and the take-up reel 13 are arranged in a direction parallel to the chassis 1 and are supported with their axes parallel to each other. Take-up reel 13
Is rotated by a winding motor 10 attached to the spinal plate of the first polishing head 7. The supply reel 12 is designed so that a predetermined load is generated in its rotation by the torque motor 9 attached to the spinal plate of the first polishing head 7.

A polishing roller 18 is arranged at a position between the supply reel 12 and the take-up reel 13. The polishing roller 18 is formed of a material such as rubber, and is rotatably attached to the lower end side of a roller support rod 17 attached to the vertebral plate of the first polishing head 7 via a support cylinder 16. ing. The roller support rod 17 is supported so as to be substantially perpendicular to the chassis 1, and is supported so as to be able to move forward and backward in the vertical direction, which is the direction in which the chassis 1 is brought into contact with and separated from the chassis 1. The polishing roller 18 has its axis of rotation parallel to the chassis 1. A cylinder device 11 attached to the spinal plate of the first polishing head 7 is provided on the upper end side of the roller support rod 17. This cylinder device 1
1 operates to move the roller support rod 17 in the vertical direction.

The polishing tape 50 is wound around the supply reel 12, passes under the polishing roller 18, and is wound around the take-up reel 13. When the take-up reel 13 is rotated by the take-up motor 10, the polishing tape 50 is sent out from the supply reel 12, guided by the polishing roller 18, and taken up by the take-up reel 13. .. At this time, since the supply reel 12 is given a predetermined load for rotation by the torque motor 9, the polishing tape 50 generates a predetermined tension.

A pair of supply reels 12, 12 and take-up reels 13, 13 are rotatably attached to the spinal plate of the second polishing head 8 on both sides of the spinal plate. ing. These supply reels 12, 1
The two and the take-up reels 13, 13 are arranged in a direction parallel to the chassis 1 and are supported with their axes parallel to each other. Each of the above take-up reels 1
The winding motors 10 and 10 attached to the spinal plate of the second polishing head 8 rotate the components 3 and 13, respectively. Each of the supply reels 12 and 12 is configured so that a predetermined load is generated in rotation by the torque motors 9 and 9 attached to the spinal plate of the second polishing head 8, respectively.

A polishing roller 18 is disposed at a position between the supply reel 12 and the take-up reel 13 on one surface side of the spinal plate of the second polishing head 8. A polishing roller 18 is also arranged at a position between the supply reel 12 and the take-up reel 13 on the other surface side of the spinal plate of the second polishing head 8. These polishing rollers 18, 18 are formed of a material such as rubber, and the lower ends of the roller support rods 17, 17 attached to the spinal plate of the second polishing head 8 via the support cylinders 16, 16, respectively. It is rotatably mounted on the side. These roller support bars 17, 17 are
The chassis 1 is supported so as to be substantially vertical,
It is supported so as to be able to move forward and backward in the vertical direction, which is the direction in which it approaches and separates from the chassis 1. Each of the polishing rollers 18, 18 has its rotation axis in a direction parallel to the chassis 1. Cylinder devices 11, 11 attached to the vertebral plate of the second polishing head 8 are provided on the upper end sides of the roller support rods 17, 17 correspondingly. These cylinder devices 11 and 11 have the above-mentioned roller support rods 17 and 17 respectively.
To move up and down.

Also in the second polishing head 8, the polishing tapes 50 and 5 are used as in the case of the first polishing head 7.
0 is wound around each of the supply reels 12 and 12 and wound around each of the take-up reels 13 and 13 via the lower side of each of the polishing rollers 18 and 18. These polishing tapes 50, 50 are used for the winding motors 1 described above.
When the take-up reels 13, 13 are rotated by 0, 10, the take-up reels 13, 13 are sent out from the supply reels 12, 12 and guided by the polishing rollers 18, 18. To be wound up.

The winding motors 10, 10, 10 are
The rotation speed is controlled by the control device to drive the rotation.

The polishing tape 50 of the first polishing head 7 is a so-called finishing polishing tape, and the disk master 110 is polished by the polishing tape 50.
It is supposed that the polishing process of the back surface part of is completed.
The polishing tape 50 supported on the one surface side of the spinal plate of the second polishing head 8 facing the first polishing head 7 is a so-called intermediate finishing polishing tape, and The diameter of the polishing particles is larger than that of the polishing tape 50. The polishing tape 50 supported on the other surface side of the spinal plate of the second polishing head 8
Is a so-called rough-finishing polishing tape in which the diameter of the polishing particles is larger than that of the above-mentioned intermediate-finishing polishing tape 50.

When the polishing heads 7 and 8 are moved along the support rails 19 and 20, they are guided by the polishing surface portions of the polishing tapes 50, 50 and 50, that is, the polishing rollers 18. The disk master 110 held by the turntable 5 in the direction in which the lower surface of the part is brought into contact with and separated from the center of rotation of the turntable 5.
Parallel to the back surface of the disk, that is, the disk master 11
It is moved in the direction of 0 inside and outside.

In the disk master back surface polishing apparatus according to the present invention configured as described above, the polishing surface portion of the polishing tape 50 is in contact with the back surface portion of the disk master disk 110 held by the turntable 5. Then, when the disk master 110 is rotated by the table motor 23, the polishing tape 50 is brought into sliding contact with the back surface of the disk master 110 to polish the back surface. At this time, the contact pressure between the disk master 110 and the polishing tape 50 is adjusted to a predetermined pressure by the cylinders 11. Then, the polishing surface portion of the polishing tape 50 is moved over the inner and outer circumferences of the disk master 110 at a predetermined constant speed to polish the entire back surface of the disk master 110.

In this polishing step, first, rough finishing is carried out with the polishing tape 50 for rough finishing, then intermediate finishing is carried out with the polishing tape 50 for intermediate finishing, and finally, finishing is carried out with the polishing tape 50 for finishing. To complete.

Since each of the polishing tapes 50 is worn as the disc master 110 is polished, the used portion is wound around each of the take-up reels 13, 13, 13 and the unused portion is removed. The rear surface of the disk master 110 is polished while being fed at a predetermined constant speed so as to be brought into sliding contact with the disk master 110 in sequence.

By the way, in this disk master back surface polishing apparatus, the control device serves as the polishing position detecting means and the disk master 110 of each of the polishing heads 7 and 8.
The position on the top is detected based on the drive pulse supplied to each of the head feed motors 42 and 43. The control device controls the rotation speed of the table motor 23 based on the detected positions of the polishing heads 7 and 8 on the disk master 110. This control device controls the rotation speed of the table motor 23, that is, the rotation speed of the turntable 5 so that the relative sliding contact speed between the disk master 110 and the polishing surface portion of the polishing tape 50 becomes substantially constant. ,Control. That is, this control device makes the rotation speed of the turntable 5 faster on the outer peripheral side as the position where the first or second polishing head 7 or 8 is polishing is on the inner peripheral side of the disk master 110. It is controlled to be slower as it is.

Therefore, in this disk master back surface polishing apparatus, the relative sliding contact speed between the back surface of the disk master 110 and the polishing surface of the polishing tape 50 is substantially constant over the inner and outer circumferences of the disk master 110. , Or
It can be changed only within a preset range. Here, the relative sliding contact speed between the disk master 110 and the polishing tape 50 is V, and the disk master 1
If the polishing amount per unit time of 10 is M, there is a relationship between the speed V and the polishing amount M, as shown in FIG. 12, that the polishing amount M becomes maximum at a predetermined speed v ₀ . That is, whether the speed V is slower or faster than the predetermined speed v ₀ , the polishing amount M becomes smaller than when the speed V is the predetermined speed V ₀ .

When the turntable 5 is rotated at a constant angular velocity, the relative sliding contact speed V between the back surface of the disk master 110 and the polishing surface of the polishing tape 50 is V.
Is over the outermost portion from the innermost portion of the disc master 110 is changed over to the fast speed v ₂ than the predetermined speed v the predetermined velocity v ₀ slower speed v ₁ than _0. Therefore, in this case, the entire back surface of the disk master 110 cannot be polished to a constant state. In the disk master backside polishing apparatus according to the present invention, the relative sliding contact speed V is maintained at the substantially predetermined speed V ₀ over the entire surface of the disk master 110, and the entire rear surface of the disk master 110 is maintained. Can be polished to a constant state.

In this disk master back surface polishing apparatus, the eccentric motor 41 is rotationally driven at a constant angular velocity during the polishing process of the back surface of the disk master 110. Therefore, the turntable 5 is moved so as to move the rotation center axis on a circular locus around the axis of the drive shaft 30 of the table motor 23. Therefore, the movement trajectory of the polishing surface portion of the polishing tape 50 on the back surface portion of the disk master 110 is on the inner peripheral side and the outer peripheral side of the disk master 110 with respect to the arc centered on the central portion of the disk master 110. It will have a wavy sway.

The reason why the movement track of the polishing surface of the polishing tape 50 with respect to the disk master 110 is such a wavy trajectory is to enhance the polishing efficiency with respect to the disk master 110. Further, in the disc master backside polishing apparatus according to the present invention, since the table motor 23 is controlled by the controller as described above, the movement locus of the polishing surface portion with respect to the disc master 110 is the disc master 110. A wavy locus having a constant shape is formed over the inner and outer circumferences. Therefore, in this disc master backside polishing apparatus, high polishing efficiency can be maintained over the entire surface of the disc master 110, and the durability of the disc master 110 can be improved.

Further, in the disk master back surface polishing apparatus according to the present invention, since the entire surface of the disk master 110 can be polished with high polishing efficiency, the amount of the polishing tape 50 used per unit polishing area is reduced. be able to.

[0060]

As described above, in the disk master back surface polishing apparatus according to the present invention, the control means includes a disk master for molding an optical disk and a polishing member which is in sliding contact with the back surface of the disk master. A change in the relative sliding contact speed over the inner and outer circumferences of the disk master is suppressed within a preset range. Therefore, in this disk master back surface polishing apparatus, the back surface portion of the disk master disk can be polished to a substantially constant state over the inner and outer circumferences of the disk master disk.

That is, the present invention can provide a disk master back surface polishing apparatus capable of polishing the back surface of a disk master used for molding an optical disk to a substantially constant state over the entire surface.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing the structure of a disk master back surface polishing apparatus according to the present invention.

FIG. 2 is a side view showing a partially cutaway view of the configuration of the disk master backside polishing apparatus.

FIG. 3 is an enlarged front view showing a configuration of a polishing head feeding device of the disk master back surface polishing device.

FIG. 4 is an enlarged vertical cross-sectional view showing the configuration of a turntable of the disk master backside polishing apparatus.

FIG. 5 is an enlarged vertical cross-sectional view illustrating a process of manufacturing a disc master for an optical disc, showing a state in which a synthetic resin layer is formed on a glass substrate.

FIG. 6 is an enlarged vertical cross-sectional view for explaining a process for manufacturing the disc master, showing a state where irregularities are formed on the synthetic resin layer.

FIG. 7 is an enlarged vertical cross-sectional view for explaining a process for manufacturing the disc master, showing a state in which a plating layer is formed on the synthetic resin layer.

FIG. 8 is an enlarged vertical sectional view of an essential part showing an enlarged plating layer formed on the synthetic resin layer.

FIG. 9 is an enlarged vertical cross-sectional view for explaining a process for manufacturing the disc master, showing a plating layer peeled off from the synthetic resin layer.

FIG. 10 is an enlarged vertical cross-sectional view for explaining a process for manufacturing the disc master, showing a state in which the back surface portion of the plating layer is polished and finished as the disc master.

FIG. 11 is an enlarged vertical cross-sectional view showing the configuration of a mold for injection-molding a disc substrate using the disc master.

FIG. 12 is a graph showing the relationship between the relative sliding contact speed of the disc master and the polishing member and the amount of polishing of the disc master.

[Explanation of symbols]

 4 ... Operation control unit 5 ... Turntable 7 ... 1st polishing head 8・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Second polishing head 18 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Polishing roller 50 ・ ・ ・ ・ ・ ・ ・ Polishing tape 110 ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Disk master

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 6, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

The synthetic resin layer 102, the metal layer 104, and the plating layer 1 thus formed in a laminated shape.
As shown in FIG. 8, reference numeral 05 has a boundary surface following the unevenness corresponding to the information signal. The depth of the unevenness indicated by the arrow c in FIG. 8 is about 0.1 μm. The thickness of the metal layer 104 shown by the arrow b in FIG. 8 is about 50 nm to 100 nm. The thickness of the plating layer 105 shown by the arrow a in FIG. 8 is about 0.3 mm.

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (1)

[Claims] 1. A turntable for holding and rotating a disk master having an uneven surface for molding a signal recording surface of an optical disk, and a disk master for rotation operation held by the turntable. A polishing member that is in sliding contact with the back surface, a polishing position detecting unit that detects the position of the polishing member on the disc master, and a position of the polishing member detected by the polishing position detecting unit on the disc master. And a control means for controlling the rotation speed of the turntable, wherein the control means controls the rotation speed of the turntable to control the relative sliding contact speed between the disk master and the polishing member. Change over the inner and outer circumference of the disc master
A disc master backside polishing device that keeps the amount within a preset range.