JP3082381B2 - Disk master backside polishing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for polishing a back surface of a disk master, which has an uneven surface for forming a signal recording surface of an optical disk, and flattens the rear surface of the disk master.

[0002]

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

In this optical disk, the other main surface of the disk substrate is optically operated by optical means.
By detecting the state of the irregularities via the disk substrate, the information signal can be read.

[0004] For forming the disk substrate, a disk master having irregularities formed on its surface, that is, a so-called stamper is used. This disk master is formed of a metal material such as nickel into a disk shape having substantially the same diameter as the disk master. The irregularities formed on the surface of the disk master correspond to the information signal, but the state of the concave and convex portions is opposite to the state on the disk substrate.

[0005] The back surface of the master disc is flat. The master disk is placed on a flat base in a molding die in an injection molding apparatus for forming the disk substrate, and the back surface is supported by the base. Further, in the step of molding the disk substrate, the disk master is pressed against the base by so-called injection pressure of the material forming the disk substrate.

Here, if there are irregularities on the back surface of the disk master, the disk master will be deformed following the irregularities on the back surface, making accurate molding impossible. Therefore, conventionally, the disk master has been used by polishing the back surface of the disk master into a so-called mirror surface by a disk master back polishing device.

The disk master back polishing apparatus has a turntable on which the disk master is mounted and which is rotated by holding the disk master. The disc master placed on the turntable is held with its back surface facing upward.

[0008] The disk master back surface polishing apparatus has a polishing member that is slidably brought into contact with the back surface of the disk master held on the turntable. The polishing member includes, for example, a so-called polishing tape formed by applying hard fine particles on a film-like base material, and a support member that supports the polishing tape, and a polishing surface of the polishing tape. Is supported so as to come into contact with the back surface of the master disc at a predetermined contact pressure. The polishing member extends in a direction in which the polishing member comes into contact with and separates from the center of rotation of the turntable and is parallel to the back surface of the disc master held by the turntable, that is, over the inner and outer peripheries of the disc master. It is movably supported in the direction.

In this disk master back 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 entire surface of the back surface of the disk master is polished by moving the polishing member over the inner and outer circumferences of the disk master.

Since the polishing tape is worn as the disk master is polished, the used portion is wound while the unused portion is being slid into contact with the disk master while the unused portion is being fed. Polish the back side of the disc master.

[0011]

In the above-described apparatus for polishing the back surface of a master disk, 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 periphery to the outer periphery of the disc master.

Therefore, the amount of polishing per unit time differs between the inner peripheral side and the outer peripheral side of the disk master, and the amount of wear of the polishing tape also differs. For this reason, it is difficult for the disk master back polishing apparatus to grind the disk master to a constant state over the inner and outer circumferences of the disk master. That is, if the amount of polishing is to be constant over the inner and outer circumferences of the disk master, the polishing time must be different between the inner and outer peripheral portions of the disk master, and it is difficult to finish the same roughness. Become.

Further, in this disk master disk backside polishing apparatus, since the amount of wear of the polishing tape per unit time is different between the inner peripheral side and the outer peripheral side of the disk master, the polishing tape feeding speed is kept constant. In this case, the polishing state changes over the inner and outer peripheral sides of the master disc.

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

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and to achieve the above-mentioned object, an apparatus for polishing a back surface of a master disk according to the present invention has an uneven surface for forming a signal recording surface portion of an optical disk. A turntable that holds and rotates the disc master that has been rotated, a polishing member that is slidably in contact with the back surface of the disc master that is held and rotated by the turntable, and a position of the polishing member on the disc master. Polishing position detecting means for detecting, and control means for controlling the rotation speed of the turntable based on the position of the polishing member on the disk master detected by the polishing position detecting means, the control means,
By controlling the rotation speed of the turntable,
A change in relative sliding contact speed between the disc master and the polishing member over the inner and outer peripheries of the disc master is suppressed within a preset range.

[0016]

In the apparatus for polishing a back surface of a disk master according to the present invention, the control means controls the relative sliding speed of the disk master for forming the optical disk and the polishing member slidably contacting the back surface of the disk master with the disk. Since the change over the inner and outer peripheries of the master is suppressed within a preset range, the back surface of the disc is polished to a substantially constant state over the inner and outer peripheries of the disc.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. The disk master backside polishing apparatus according to the present invention is a disk master used for forming a disk substrate of an optical disk by providing fine unevenness corresponding to an information signal on one main surface portion of the disk substrate, a so-called stamper. , A device for polishing the back surface. The disk substrate is formed of a transparent synthetic resin material such as polycarbonate or polymethyl methacrylate. The optical disk is constructed by forming a reflective film made of aluminum or the like on the one main surface of the disk substrate on which the irregularities are formed by means such as evaporation or sputtering.

The disk master is formed of a metal material such as nickel into a disk shape having substantially the same diameter as the disk master. Irregularities corresponding to the information signals are formed on the surface of the master disk. The concave and convex portions are in a state where the concave portions and the convex portions are opposite to the state on the disk substrate.

Here, a brief description will be given of a manufacturing process of the disk master. To manufacture the disk master, first, a flat synthetic resin layer 102 is formed on a flat glass substrate 101 as shown in FIG. This synthetic resin layer 10
For example, an ultraviolet curable resin or the like is used as the material forming the second material. Next, as shown in FIG. 6, a concavo-convex pattern corresponding to the information signal is formed on the synthetic resin layer 102 by using the focused laser beam 103.

A metal layer 104 is formed on the synthetic resin layer 102 on which the unevenness corresponding to the information signal is formed by means of so-called electroless plating or sputtering. 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 1
As shown in FIG. 8, reference numeral 05 has a boundary surface following the unevenness corresponding to the information signal. Note that the depth of the irregularities indicated by the arrow c in FIG. 8 is about 0.1 μm. The thickness of the metal layer 104 indicated by an arrow b in FIG. 8 is about 50 nm to 100 nm. The thickness of the plating layer 105 indicated by an arrow a in FIG. 8 is about 0.3 mm.

Then, the upper surface portion 105 of the plating layer 105
In FIG. 8A, unevenness having a depth of about 5 to 10 μm indicated by an arrow d in FIG. 8 is present. The irregularities are generated in the plating process.

Next, as shown in FIG.
4 and the plating layer 105 are peeled off from the synthetic resin layer 102. Then, as shown in FIG.
The disk master 110 is formed by polishing the upper surface portion 105a of the disk 05 by a disk master back surface polishing apparatus according to the present invention to remove the above-mentioned irregularities and make the mirror surface. The upper surface portion 105a of the plating layer 105 is
10 back surface.

The polishing of the back surface of the disk master 110 is performed by rotating the disk master 110 as shown by an arrow R in FIG. 10, and polishing the polishing tape 50 supported by the polishing roller 18 serving as a polishing member. This is done by sliding on the part. The polishing tape 50 is fed and guided by the polishing roller 18 as indicated by an arrow S in FIG.

The polishing of the rear surface of the disk master 110 in this manner is performed in such a manner that the disk master is deformed in accordance with the irregularities present on the rear surface in a mold for forming the disk substrate, thereby achieving accurate molding. This is to prevent that is hindered.

In the injection molding apparatus for molding the disk substrate, the disk master 110 is placed on a flat upper surface of a lower die 106 constituting a molding die, and the lower surface is placed on the lower surface. It is supported by the mold 106. An upper mold 107 constituting the above-mentioned mold is abutted on the lower mold 106. The upper die 107 and the disk master 110
A gap portion corresponding to the thickness of the disk substrate is formed between.

The disk substrate is formed by injecting a molten material for the disk substrate at a predetermined injection pressure into a gap between the disk master 110 and the upper die 107 via a gate 108. By doing so.

The apparatus for polishing the back surface of a disk master according to the present invention has an outer casing 2 as shown in FIG. A chassis 1 is provided at a substantially central portion in the outer housing 2 so as to divide the outer housing 2 into upper and lower parts. A portion of the outer housing 2 above the chassis 1 is a door 3 whose front portion is openable and closable. A control device (not shown) serving as control means is accommodated in a portion of the outer housing 2 below the chassis 1. The control device includes 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.
And a water supply / drainage pipe 15 for cooling.

The disk master 110 is mounted on the chassis 1, and a turntable 5 for holding and rotating the disk master 110 is provided. As shown in FIG. 4, the turntable 5 has a plurality of master disc holding members 28, 28 on the outer peripheral portion. The turntable 5 is used to hold the disk master holding members 2.
8 and 28, the disk master 110 is held with its back surface facing upward.

The turntable 5 is mounted on the chassis 1
It is attached to a table support 35 on the upper end side of a support shaft 32 rotatably supported with respect to, and is rotatably supported with respect to the chassis 1. The support shaft 32 is supported so that its axis is substantially perpendicular to the chassis 1.

The support shaft 32 is supported by the chassis 1 via an outer tubular member 27 and an inner tubular member 34. That is, approximately in the center of the chassis 1,
The outer cylinder member 27 is fixedly attached so as to fit into an opening formed in the chassis 1.
The outer cylinder member 27 is formed in a substantially cylindrical shape, and has an axis perpendicular to the chassis 1. This outer cylinder member 2
The inner cylindrical member 34, which is formed in a substantially cylindrical shape, is fitted into and supported by a pair of rotary bearings 37, 37. The inner cylinder member 34 has an axis of a cylindrical surface forming an outer peripheral surface coincident with the axis of the outer cylinder member 27, and is rotatable around the axis with respect to the outer cylinder member 27. . The inner cylindrical member 34 has a belt wheel 38 provided on the lower end side protruding below the lower end of the outer cylindrical member 27. The belt wheel portion 38 is provided with the inner cylindrical member 34.
Are coaxial with respect to the outer peripheral surface.

The cylindrical surface forming the inner peripheral portion of the inner cylindrical member 34 is eccentric with respect 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 cylindrical member 34 via a pair of rotation bearings 36, 36. In other words, this support shaft 32 is indicated by an arrow R in FIG.
As shown by, the inner cylinder member 34 is rotatable about an axis with respect to the inner cylinder member 34, and when the inner cylinder member 34 is rotated with respect to the outer cylinder member 27, 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 of the member 34.

The support shaft 32 is rotated via an intermediate shaft 26 by a table motor 23 disposed below the chassis 1. The table motor 23 is
A plurality of columns 24 and 25 are provided on the lower surface of the chassis 1.
And mounted on and supported by a motor support plate 28 which is mounted via a motor. The table motor 23 directs the drive shaft 30 to the upper side on the chassis 1 side. The lower end of the intermediate shaft 26 is connected to the distal end of the drive shaft 30 via a first free joint (universal joint) 29. The upper end of the intermediate shaft 26 is connected to the lower end of the support shaft 32 via a second free joint 31. That is, the table motor 23 is configured such that the support shaft 32 is
The rotation of the drive shaft 30 with respect to the outer cylinder member 27
The support shaft 32 can be rotated even if the position is eccentric with respect to. This table motor 23
The rotation speed is controlled by the control device, and the rotation is performed.
The periphery of the intermediate shaft 26 is covered with a bellows member 33 made of a synthetic resin material.

The inner cylindrical member 34 is connected to the outer cylindrical member 27 via an endless drive belt 39 and a belt wheel 38 by an eccentric motor 41 disposed below the chassis 1. Is rotated. The eccentric motor 41 is fixed to 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 looped. The eccentric motor 41 is rotated by the control of the control device.

As shown in FIG. 1 to FIG.
For supporting the polishing tape 50 serving as a polishing member for polishing the back surface of the disk master 110 held thereon,
It has first and second polishing heads 7 and 8. The polishing tape 50 is formed, for example, by forming hard fine particles on a tape-shaped base material.

Each of the polishing heads 7 and 8 is movably supported on the chassis 1 by a polishing head support plate 6 disposed at a position behind 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 a front surface portion facing the turntable 5. These support rails 19 and 20 are parallel to the chassis 1. The spine plates of the polishing heads 7, 8 are supported at their base ends by the support rails 19, 20, and along the support rails 19, 20, as indicated by arrows T in FIGS. In addition, it is possible to move 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 a first head feed motor 42 attached to the polishing head support plate 6. That is, the first head feed motor 42 is provided with a pair of bearings 4 for the polishing head support plate 6.
The first screw shaft 22, which is rotatably mounted via 4, 45, is rotated. The first screw shaft 22 is disposed in parallel with the support rails 19 and 20. The first screw shaft 22 is screwed with a first screw ring 46 attached to the base end of the spine plate of the first polishing head 7. When the first screw shaft 22 is operated to rotate, the first screw ring 46 is moved 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 driven by the second head feed motor 43 attached to the polishing head support plate 6 to each of the support rails 19, Movement operation is performed along 20. That is, the second head feed motor 43 rotates 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
The support rails 19 and 20 are arranged in parallel with each other.
The second screw shaft 21 is screwed with a second screw ring 49 attached to the base end of the spine plate of the second polishing head 8. When the second screw shaft 21 is rotated, the second screw shaft 21 is rotated.
The screw ring 49 is fed along with the second polishing head 8 in the axial direction of the second screw shaft 21.

The head feed motors 42, 43
Is a so-called stepping motor, which is capable of controlling the amount of rotation and detecting the rotation angle. Further, these head feed motors 42,
Reference numeral 43 controls the rotation speed and the rotation angle amount by the control device, and drives the rotation.

Each of the polishing heads 7 and 8 is configured so that the polishing tape 50 comes into contact with the back surface of the disk master 110 on the turntable 5 at a predetermined contact pressure.

That is, a supply reel 12 and a take-up reel 13 are provided on the spine plate of the first polishing head 7.
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 supported with their axes parallel to each other. The take-up reel 13
Is rotated by a winding motor 10 attached to the spine plate of the first polishing head 7. The supply reel 12 is configured so that a predetermined load is generated in rotation by a torque motor 9 attached to a spine plate of the first polishing head 7.

A polishing roller 18 is provided 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 a lower end side of a roller support rod 17 attached to the spine 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 advance and retreat in a vertical direction in which the roller 1 comes in contact with and separates from the chassis 1. The polishing roller 18 has a rotation axis parallel to the chassis 1. A cylinder device 11 attached to the spine plate of the first polishing head 7 is provided on the upper end side of the roller support bar 17. This cylinder device 1
1 moves the roller support bar 17 up and down.

The polishing tape 50 is wound around the supply reel 12, and is wound around the take-up reel 13 via the lower side of the polishing roller 18. 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 is generating a predetermined tension.

A pair of supply reels 12, 12 and take-up reels 13, 13 are rotatably mounted on the spine plate of the second polishing head 8 on both side surfaces of the spine plate. ing. These supply reels 12, 1
The take-up reels 2 and the take-up reels 13 are arranged in a direction parallel to the chassis 1 and supported with their axes parallel to each other. Each take-up reel 1
The spinning motors 3, 13 are respectively operated by winding motors 10, 10 attached to the vertebral plate of the second polishing head 8. Each of the supply reels 12 and 12 is configured such that a predetermined load is generated in rotation by torque motors 9 and 9 attached to the vertebral 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 side of the spine plate of the second polishing head 8. A polishing roller 18 is also provided at a position between the supply reel 12 and the take-up reel 13 on the other side of the spine plate of the second polishing head 8. The polishing rollers 18 are formed of a material such as rubber, and the lower ends of roller support rods 17 attached to the spine plate of the second polishing head 8 via support cylinders 16, respectively. It is rotatably mounted on the side. These roller support rods 17, 17
It is made substantially perpendicular to the chassis 1 and supported,
It is supported so as to be able to advance and retreat in the vertical direction, which is the direction in which the chassis 1 comes and goes. Each of the polishing rollers 18 has a rotation axis in a direction parallel to the chassis 1. On the upper end side of each of the roller support rods 17, cylinder devices 11, 11 attached to the spine plate of the second polishing head 8 are provided correspondingly. These cylinder devices 11, 11 are provided with the roller support rods 17, 17, respectively.
Is moved up and down.

In the second polishing head 8, similarly to the first polishing head 7, the polishing tapes 50, 5
0 is wound around the supply reels 12, 12, and is wound around the take-up reels 13, 13 under the polishing rollers 18, 18. These polishing tapes 50, 50 are connected to the respective winding motors 1 described above.
When the take-up reels 13 are rotated by 0 and 10, the take-up reels 13 are sent out from the supply reels 12 and guided by the polishing rollers 18 so that the take-up reels 13 are rotated. It is wound up.

Each of the winding motors 10, 10, 10 is
The rotation speed is controlled by the control device, and the rotation is performed.

The polishing tape 50 of the first polishing head 7 is a so-called finishing polishing tape.
Is to be completed.
The polishing tape 50 supported on one side of the spine plate of the second polishing head 8 which faces the first polishing head 7 is a so-called semi-finishing polishing tape, The diameter of the abrasive particles is larger than that of the abrasive tape 50 of FIG. A polishing tape 50 supported on the other side of the vertebral plate of the second polishing head 8
Is a polishing tape for so-called rough finishing, in which the diameter of abrasive particles is larger than that of the polishing tape 50 for semi-finishing.

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, that is, the polishing roller 18. The disc master 110 held in the turntable 5 in a direction in which the lower surface of the portion is brought into contact with and separated from the rotation center of the turntable 5.
In the direction parallel to the back surface of the disk master,
0 in the direction extending over the inner and outer circumferences.

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

In this polishing step, first, rough finishing is performed using a polishing tape 50 for rough finishing, then, medium finishing is performed using a polishing tape 50 for medium finishing, and finally, finishing is performed using a polishing tape 50 for finishing. Is completed.

Since each of the polishing tapes 50 is worn as the disk master 110 is polished, a used portion is wound around each of the take-up reels 13, 13, and an unused portion is taken up. The back surface of the disk master 110 is polished while being fed at a predetermined constant speed so as to sequentially contact the disk master 110.

In this apparatus for polishing the back surface of a disk master, the control device controls the disk master 110 of each of the polishing heads 7 and 8 as a polishing position detecting means.
The upper position is detected based on the driving pulses supplied to 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. The control device controls the rotation speed of the table motor 23, that is, the rotation speed of the turntable 5, such that the relative sliding contact speed between the disk master 110 and the polishing surface of the polishing tape 50 becomes substantially constant. ,Control. That is, the control device increases the rotation speed of the turntable 5 on the outer peripheral side as the position where the first or second polishing head 7, 8 is polishing is on the inner peripheral side of the disk master 110. Control so that it becomes slower as much as possible.

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 made to change 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
Assuming that 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 lower or higher than the predetermined speed v ₀ , the polishing amount M is smaller than when the speed V is the predetermined speed V ₀ .

When the turntable 5 is rotated at a constant angular speed, 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 determined.
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 apparatus for polishing a back surface of a disk master according to the present invention, the relative sliding speed V is maintained at the predetermined speed V ₀ substantially over the entire surface of the disk master 110, and the entire surface of the back surface of the disk master 110 is maintained. Can be polished to a constant state.

Further, in the disk master back polishing apparatus, the eccentric motor 41 is driven to rotate at a constant angular speed during the polishing process of the rear surface of the disk master 110. Therefore, the turntable 5 is moved so that the rotation center axis moves on a circular locus about the axis of the drive shaft 30 of the table motor 23. Therefore, the movement locus of the polishing surface portion of the polishing tape 50 on the back surface portion of the disk master 110 is on the inner and outer peripheral sides of the disk master 110 with respect to an arc centered on the center of the disk master 110. The trajectory is like a wave.

The movement locus of the polishing surface portion of the polishing tape 50 with respect to the disk master 110 is set as such a wavy locus in order to increase the efficiency of polishing the disk master 110. In the disc master back polishing apparatus according to the present invention, since the table motor 23 is controlled by the control device as described above, the movement locus of the polishing surface portion with respect to the disc master 110 is A wave-like locus having a constant shape is formed over the inner and outer circumferences. Therefore, in the disk master back polishing apparatus, high polishing efficiency can be maintained over the entire surface of the disk master 110, and the durability of the disk master 110 can be improved.

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

[0060]

As described above, in the apparatus for polishing a back surface of a disk master according to the present invention, the control means controls the operation of the disk master for forming the optical disk and the polishing member slidably contacting the back surface of the disk master. The change in the relative sliding speed over the inner and outer peripheries of the disc master is suppressed within a preset range. Therefore, in the disk master back polishing apparatus, the back surface of the disk master can be polished to a substantially constant state over the inner and outer circumferences of the disk master.

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

[Brief description of the drawings]

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

FIG. 2 is a side view, partially broken away, showing the configuration of the disk master back surface 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 sectional view showing a configuration of a turntable of the disk master back surface polishing apparatus.

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

FIG. 6 is an enlarged vertical cross-sectional view illustrating a process of manufacturing the master disc, showing a state in which irregularities are formed in the synthetic resin layer.

FIG. 7 is an enlarged vertical cross-sectional view illustrating a process of manufacturing the disk master and shows a state where a plating layer is formed on the synthetic resin layer.

FIG. 8 is an enlarged longitudinal sectional view showing a main part of a plating layer formed on the synthetic resin layer in an enlarged manner.

FIG. 9 is an enlarged vertical cross-sectional view illustrating a process of manufacturing the disk master, and shows a plating layer peeled off from the synthetic resin layer.

FIG. 10 is an enlarged vertical cross-sectional view for explaining a process of manufacturing the disk master, showing a state where the back surface of the plating layer is polished to finish the disk master.

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

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

[Explanation of symbols]

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

Claims (1)

(57) [Claims] 1. A turntable for holding and rotating a disc master having an uneven surface for forming a signal recording surface of an optical disc, and a turntable for holding and rotating the disc master held by the turntable. A polishing member slidably in contact with the back surface portion; a polishing position detecting means for detecting a position of the polishing member on the disk master; and a position of the polishing member on the disk master detected by the polishing position detecting means. Control means for controlling the rotation speed of the turntable based on the rotation speed of the turntable, whereby the control means controls the rotation speed of the turntable, thereby controlling the relative sliding speed of the disc master and the polishing member. Change over the inner and outer circumference of the disc master
An apparatus for polishing the back surface of a master disc, which is kept within a preset range.