JPH07232354A - Disc master for molding disc substrate, mold and combination thereof - Google Patents

Abstract

PURPOSE:To reduce wear of the contact surface between a disc master and the mirror finished surface of a mold, suppress the amount of deformation of the disc master and prolong its lifetime by a method wherein wear relieving layer, which is made of metallic or ceramic film having the specified hardness, is provided on the rear surface of the disc master. CONSTITUTION:On the rear surface of a disc master made of Ni or the like, wear relieving layer 15 made of metallic film or ceramic film having the hardness of Hv 250 or higher is provided. In this case, the metallic film or ceramic film preferably has the coefficient of dynamic friction, which is measured by the pin-on-disc abrasion test with SUJ 2 pin, of 0.01-0.6. A wear-relieving layer, the metallic film of which is metal plated film, in which at least one selected from the group of lubricous particle consisting of silicon, molybdenum, PTFE and the like is dispersed, is provided. Further, the ceramic film is preferably made of PVD or CVD.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for molding an optical disk substrate and a disk master (stamper).

[0002]

2. Description of the Related Art Optical disks are currently manufactured by injection molding. The disc mold has a pit,
In order to transfer information such as grooves to the disc, a disc master is mounted on one of the mold mirror surfaces. For the disc master used for disc molding, photoresist is applied on the glass master disc with optical accuracy, and after cutting information such as pits and grooves, a conductive film is formed by sputtering, etc., and nickel etc. is formed on it. Electroforming. The thin plate of nickel or the like thus formed is peeled from the glass master, the inner and outer diameters are punched out, and the back surface is polished to finish, whereby the disk master is obtained. However, since the disk master was made by nickel electroforming or the like, sufficient strength could not be obtained. In particular, in molding a recordable disc that requires higher temperature and pressure than a CD or the like, the cost and time required for repair and replacement of the disc master cannot be ignored because the disc master deteriorates quickly.

Similarly, the same can be said for the mirror surface of the mold. The disk master mounting side mirror surface is mirror-polished of a steel material having hardness that can withstand disk molding and dimensional accuracy against fluctuations in temperature, and is then coated with a high hardness such as TiN (PVD) or TiCN (plasma CVD). . In the coating or the like, the degree of deformation between the disk master and the mirror surface of the mold is different, so that a frictional wear phenomenon occurs on the contact surface. In addition, shocks are added when the mold is clamped. At this time, the conventional disc master with inferior hardness was damaged,
Then the coating on the mirror surface of the mold is damaged. As the deterioration of the coating progresses, the underlying steel material will also be damaged, so the cost of repairing and replacing the mirror surface of the mold
Time has become something that cannot be ignored.

As described above, the cost and time required for the repair and replacement of the master disk and the mirror surface of the mold have a great influence on the disk molding.

The disk molding is performed under high temperature and high pressure, and at the portion where the back surface of the disk master and the mirror surface of the mold come into contact with each other, expansion and contraction due to heat, plastic deformation, deformation when the molded product is released from the mold, and the like. The mirror surface of the mold is damaged.
Since the disk master and the mirror surface of the mold are made of different materials and have different coefficients of thermal expansion, rigidity, etc., a frictional wear phenomenon occurs due to deformation of the disk master having poor hardness at the contact surface. This time,
A conventional disk master having a hardness lower than the mirror surface of the mold is damaged by a peeling phenomenon due to friction, and the accuracy required for disk molding cannot be maintained during repeated molding. As a result, when the master disk is damaged, the missing material becomes an abrasive and promotes the deterioration of the mirror surface.

An object of the present invention is to determine the amount of wear between the contact surface between the disk master and the mold mirror surface in the friction and wear phenomenon involving deformation of the disk master and the mirror surface of the mold under high temperature and high pressure. The object is to provide a disk master and a mold mirror surface that have a long life by alleviating and suppressing the deformation amount of the disk master.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a wear-relieving layer made of a metal film or a ceramic film having a hardness of Hv250 or more on the back surface of a disk master made of Ni or the like for the purpose of solving the above problems. This improves wear resistance and lubricity and extends the life of the disk master and the mirror surface of the mold.

A preferred metal film is a metal film such as a metal plating film in which at least one selected from the group consisting of silicon, molybdenum and polytetrafluoroethylene (PTFE) and other lubricating particles is dispersed. The film containing a lubricating substance such as PTFE is preferably one in which PTFE or the like is dispersed in a Ni—P electroless plating film or a Cr plating film. Other preferable metal films include a Cr-only plating film and a Ni-P electroless plating film. Preferred ceramic membranes include Al ₂ O ₃ , BN, CrN, TiAl
There is N.

The metal film or the ceramic film that constitutes the wear-relieving layer is a pin-on / pull-on pin made by SUJ2.
It is preferable to have a dynamic friction coefficient of 0.01 to 0.6 in the disc friction wear test. In these cases, the hardness of the wear relaxation layer is higher than that of the disc master (Hv about 250 to 90).
0, preferably about 300-400 Hv). Further, the hardness of the wear-relieving layer is preferably softer than the hardness of the coating such as TiN on the metal mirror surface (Hv of TiN: about 2300), so that the wear-relieving layer has lubricity and durability due to an appropriate hardness. The life of the master and the mirror surface of the mold can be extended.

The present invention also provides a mold mirror surface for supporting a disk master made of Ni or the like used for injection molding of an optical disk, wherein at least one kind of silicon particles, molybdenum particles, PTFE particles and the like is dispersed on the mold mirror surface. Ni
A feature is that a wear relaxation layer made of a metal plating film such as P plating is provided. Also according to this aspect, the life of the disk master and the mirror surface of the mold can be extended by combining the lubricity of the wear-relieving layer and the durability due to the appropriate hardness.

Further, according to the present invention, the back surface of the disc master and
Silicon particles, molybdenum particles and P on both surfaces of the mold
A wear relaxation layer made of a Ni-P plated film in which at least one kind of TFE particles or the like is dispersed can be provided. In this case, the hardness of the wear reducing layer on the disk master side is made smaller than that on the metal mirror surface side.

In each of the above cases, the hardness relationship is generally made smaller in the order of coating the mirror surface of the die, coating the back surface of the disk master, and then the disk master. In consideration of wear resistance, by giving the above hardness difference, the disk master can be generally treated as a consumable item, and the die mirror surface can be a durable surface. Generally, the required characteristics for the die mirror surface and the disc master are that the die mirror surface side is hard, the disc master side has an appropriate hardness on the back side of the disc master, the sliding between them is good, and the shape accuracy is Is more accurate and the back surface of the disk master has a sufficient accuracy (for example, Rmax is about 40 nm and the back surface of the disk master is about 2.0 to 3.0 μm). If the latter becomes too rough, the product characteristics will be adversely affected.

[0013]

In the die mirror surface of the present invention, the frictional wear phenomenon occurring between the disk master and the die mirror surface improves the slidability of both surfaces, and the deterioration phenomenon due to wear is reduced.
Therefore, it is possible to reduce the cost and time required for the repair / replacement of the disk master and the mirror surface of the mold, which are conventionally required.

[0014]

FIG. 5 shows an embodiment of the present invention. The disk mold 10 according to the embodiment of the present invention is an optical disk master 13.
And a disk master 17 composed of a film 15 for improving wear resistance. The forming procedure is shown below.

First, in FIG. 1, a masking agent 11 is coated to protect the information surface 12 of an optical disk master 13 produced by a conventional manufacturing method. Then, on the back surface 14 of the optical disk master 13, as shown in FIG. 2 (rotated by 180 degrees in FIG. 1), a film 1 for the purpose of improving wear resistance is provided.
5 is provided. When the roughness of the film 15 is not uniform, the film surface 15A is polished and used as shown in FIG. afterwards,
As shown in FIG. 3, by removing the masking agent 11 from the information surface 12 of the optical disc master, a disc master 17 having high wear resistance as shown in FIG. 4 is obtained. The disc master 17 thus obtained is fixed as the die mirror surface 16 and the film 15 are in contact with each other as shown in FIG. In Examples 1 to 11 below, the metal mirror surface used was a TiN film.

Next, an embodiment will be described in which a metal film is formed as a wear-relieving layer on the back surface of the master disk.

Example 1 A hard chrome plating layer having a Vickers hardness of about 1,000 is provided on the rear surface of the disk master in contact with the mirror surface of the die to a thickness of 0.3 μm. Surface roughness Rmax is 2 μm
Met. The nickel base on the back of the disc master is SUJ
The friction coefficient of 1.2 on the pin-on-disk friction test using the pin made by No. 2 is 1.2, while the plating film has 0.4 and the hardness increases and the friction coefficient decreases, so that the friction wear phenomenon occurs. Is reduced. When a molding experiment was performed on the disk master provided with the plating layer, it was twice as much as the conventional product in which no film was formed on the back surface until an error due to deterioration of the disk master was observed on the molded disk substrate. It took some time.

(Embodiment 2) A nickel-boron electroless plating layer of 4 μm was provided on the back surface of the disk master in contact with the mirror surface of the mold. The film thickness after polishing this surface was 3 μm. This layer has a Vickers hardness of 900 and a high wear resistance with a friction coefficient of 0.6 in the friction wear test. It took about twice as much time as the conventional product in which no film was formed on the back surface until an error caused by deterioration of the master disk provided with the layer was observed.

(Embodiment 3) 7 μm of a layer in which PTFE particles are dispersed by nickel-phosphorus electroless plating is provided on the back surface of the disk master in contact with the mirror surface of the mold. Heat treatment was applied to the dispersion layer, and this surface was polished to a film thickness of 3 μm. This layer had a Vickers hardness of 350 and a friction coefficient of 0.
02, which has a high wear resistance. The surface roughness Rmax after polishing this surface was 2.5 μm. It took about 5 times as long as that of a conventional product in which a film was not formed on the back surface until an error due to deterioration of the master disk provided with the dispersion layer was observed.

(Embodiment 4) A layer in which PTFE particles are dispersed by nickel-phosphorus electroless plating is provided in a thickness of 7 .mu.m on the back surface of the disk master in contact with the mirror surface of the die. The thickness of this surface after polishing is 3 μm, the surface roughness Rmax is 2.5 μm, and the dispersion layer has a high Vickers hardness of 250 and a friction coefficient of 0.1 in the friction wear test and high wear resistance. There are layers.
It took about three times as long as that of a conventional product in which a film was not formed on the back surface until an error due to deterioration of the master disk provided with the dispersion layer was observed.

Example 5 Si particles were used in place of the PTFE particles in Example 3. It was plated to a thickness of 5 μm and then polished to a thickness of 3 μm. The dispersion layer had a Vickers hardness of 400 and a friction coefficient of 0.4 in the friction wear test.
A layer with high wear resistance is formed. It took about 2.5 times as long as that of a conventional product in which a film was not formed on the back surface until an error due to deterioration of the master disk provided with the dispersion layer was observed.

(Example 6) In Example 3, Mo particles were used in place of the PTFE particles. It was plated to a thickness of 5 μm and then polished to a thickness of 2 μm. The dispersion layer had a Vickers hardness of 400 and a friction coefficient of 0.3 in the friction wear test.
A layer with high wear resistance is formed. It took about 2.5 times as long as that of a conventional product in which a film was not formed on the back surface until an error due to deterioration of the master disk provided with the dispersion layer was observed.

(Embodiment 7) Two layers of Cr-plated PTFE particles dispersed on the back surface of the disk master in contact with the mirror surface of the die are used.
μm was provided. The dispersion layer can be a layer having a Vickers hardness of 500 and a high wear resistance with a friction coefficient of 0.1 in the friction wear test. It took about four times as long as that of a conventional product in which a film was not formed on the back surface until an error caused by deterioration of the master disk provided with the dispersion layer was observed.

The case where the metal film is used as the wear reducing layer on the back surface of the disk master has been described above. Next, an embodiment in which a ceramic film is formed on the back surface of the disk master will be described.

(Embodiment 8) An alumina layer is formed on the rear surface of the disk master in contact with the mirror surface of the die by a plasma CVD method to a thickness of 1 μm.
Set up. The alumina layer had a Vickers hardness of 2,100 and a friction coefficient of 0.2 in the friction wear test. When a molding experiment was carried out on a disk master provided with the alumina layer,
It took about 5 times as long as the time required for an error due to deterioration of the master disk to be observed on the molded disk substrate as compared with the conventional product in which no film was formed on the back surface.

(Embodiment 9) A boron nitride layer having a thickness of 2 μm was provided on the back surface of a disk master in contact with the mirror surface of a mold by a sputtering method. The boron nitride layer has a Vickers hardness of 3,500 and a friction coefficient of 0.2 in the friction and wear test. When a molding test was conducted on the disk master provided with the boron nitride layer, a molded disk substrate of the disk master was tested. No error due to deterioration was observed even after four times as long as that of the conventional product in which no film was formed on the back surface.

(Embodiment 10) A CrN layer was formed on the back surface of the disk master in contact with the mirror surface of the mold by ion plating.
μm was provided. The CrN layer has a Vickers hardness of 2,000 and a friction coefficient of 0.3 in the friction and wear test.
When a molding experiment was performed on a disk master with layers, by the time an error due to deterioration of the disk master was found on the molded disk substrate, it was about three times as large as that of the conventional product in which no film was formed on the back surface. took time.

(Embodiment 11) A TiAlN layer having a thickness of 3 μm was provided on the back surface of a disk master in contact with the mirror surface of a mold by an ion plating method. The TiAlN layer has a Vickers hardness of 2,
200 and a friction coefficient of 0.4 in the friction wear test,
When a molding experiment was performed on the disc master provided with the TiAlN layer, three times as much as that of the conventional product in which no film was formed on the back surface until an error due to deterioration of the disc master was observed on the molded disc substrate. It took some time. The results of Examples 1 to 11 above are summarized in Table 1.

[0029]

[Table 1]

In each of the above embodiments, the wear reducing layer was formed on the back surface of the disk master, but the following shows an example of forming the wear reducing layer on the mirror surface of the mold. First, as shown in FIG. 6, the masking agent 21 is applied to the side surface of the mirror surface 26 of the mold finished by lapping and polishing with diamond or the like. Thereafter, as shown in FIG. 7, the PTFE dispersion type electroless plating composite coating 25 is provided on the die mirror surface 26. Similar to the above, the PTFE composite coating surface 25A needs to be polished, and when the masking agent 21 is removed and then polishing is performed using a means such as lapping, the mold mirror surface 26 having high wear resistance as shown in FIG. 8 is obtained. can get. The die mirror surface 26 thus obtained is fixed so that the PTFE composite coating 25 and the disc master 23 are in contact with each other as shown in FIG. 9, and is used as the disc die 20.

(Embodiment 12) A layer of PTFE particles dispersed in nickel-phosphorus electroless plating is provided on the mirror surface of the die to a thickness of 7 μm, and the dispersion layer is heat treated and then polished to a thickness of 3 μm.
m. A layer with high wear resistance having a Vickers hardness of 900 and a friction coefficient of 0.02 in the friction wear test is formed. Before the error due to the deterioration of the disk master provided with the dispersion layer is observed, the film thickness of the conventional 5
It took about twice as long.

(Embodiment 13) Nickel-phosphorus electroless plating was applied on the mirror surface of the mold to form a layer having 5 μm of Si particles dispersed therein,
The dispersion layer was heat treated and then polished to a thickness of 3 μm. A layer with high wear resistance having a Vickers hardness of 900 and a friction coefficient of 0.4 in the friction wear test is formed. It took about twice as long as that of a conventional product in which a film was not formed on the back surface until an error caused by deterioration of a disk master provided with the dispersion layer was observed.

(Embodiment 14) 5 μm of a layer in which Mo particles are dispersed is provided on nickel-phosphorus electroless plating on the mirror surface of a die,
The dispersion layer was heat treated and then polished to a thickness of 2 μm. A layer with high wear resistance having a Vickers hardness of 900 and a friction coefficient of 0.3 in the friction wear test is formed. It took about twice as long as that of a conventional product in which a film was not formed on the back surface until an error caused by deterioration of a disk master provided with the dispersion layer was observed.

(Embodiment 15) The mirror surface of the mold is plated with Cr and then P
A layer in which TFE particles were dispersed was provided in a thickness of 2 μm. Vickers hardness of 1,000 and a friction coefficient of 0.1 in the friction wear test
A layer with high wear resistance is formed. It took about four times as long as that of a conventional product in which a film was not formed on the back surface until an error caused by deterioration of the master disk provided with the dispersion layer was observed. The results of Examples 12 to 15 are summarized in Table 2.

[0035]

[Table 2]

(Examples 16 to 17) Table 3 shows an example in which a plating film in which lubricating particles are dispersed is formed as a wear-relieving layer on the back surface of the disk master and the mirror surface of the mold, and is used in combination.

[0037]

[Table 3]

[0038]

EFFECTS OF THE INVENTION The disk mold formed by the above two steps has a shorter life than the conventional product because the abrasion between the back surface of the disk master and the mirror surface of the mold is reduced under high temperature and high pressure. It has become possible to postpone. As a result, it is possible to reduce the cost and time required for repair and replacement of the master disk and the mirror surface of the mold. While the preferred and presently contemplated embodiments of the invention have been illustrated and described, it will be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. . All such changes and modifications should be included in the technical idea of the present invention.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state of a first stage in which a masking agent is coated to protect an information surface of an optical disc master according to the present invention.

FIG. 2 is a cross-sectional view of a second stage state in which a film for improving abrasion resistance is provided on the back surface of an optical disk master according to the present invention.

FIG. 3 is a cross-sectional view showing a third stage state of removing the masking agent from the back surface of the optical disc master in the state of FIG. 2 according to the present invention.

FIG. 4 is a cross-sectional view of an optical disc master provided with a film for improving the wear resistance obtained according to the present invention.

FIG. 5 is a cross-sectional view of a disk mold using an optical disk master obtained according to the present invention.

FIG. 6 is a cross-sectional view showing a state of a first stage in which a masking agent is applied to the side surface of a mirror surface of a mold according to the present invention.

FIG. 7 is a cross-sectional view of a second stage state in which a PTFE composite coating is provided on the mirror surface of a mold according to the present invention.

FIG. 8 is a cross-sectional view of a mirror surface of a mold provided with a PTFE composite coating obtained according to the present invention.

FIG. 9 is a cross-sectional view of a disk mold equipped with a disk master using the mold mirror surface obtained according to the present invention.

[Explanation of symbols]

 10, 20 Disk mold 11, 21 Masking agent 12 Information surface of the disk master 13, 23 Disk master 14 Back surface of the disk master 15 A film intended to improve wear resistance 15A Improves wear resistance Target film surface 16, 26 Mold mirror surface 17 Disc master with wear-relief layer 25 PTFE composite coating 25A PTFE composite coating surface

Claims (6)

[Claims] 1. A disc master used for injection molding of an optical disc, wherein the hardness of the back side of the disc master is Hv2.
A disc master having a wear-reducing layer made of 50 or more metal or ceramic films. 2. The metal film or ceramic film is SU.
The disk master according to claim 1, which has a dynamic friction coefficient of 0.01 to 0.6 in a pin-on-disk friction and wear test using a J2 pin. 3. The disk master according to claim 1, wherein the metal film is provided with a wear-reducing layer made of a metal plating film in which at least one selected from the group consisting of lubricating particles such as silicon, molybdenum and PTFE is dispersed. 4. The ceramic film is PVD or CVD.
The disc master according to claim 1, which is formed by 5. A metal plating in which at least one selected from the group consisting of lubricating particles such as silicon, molybdenum and PTFE is dispersed on the mirror surface of a mold for supporting a disk master used for injection molding of an optical disk. A mold for molding a disk, comprising a wear-relieving layer made of a film. 6. A combination of a disk master used for injection molding of an optical disk and a mirror surface of a mold for supporting the disk master, wherein the back surface of the disk master and the metal mirror surface are composed of lubricating particles such as silicon, molybdenum and PTFE. Characterized in that first and second wear mitigating layers each comprising a metal plating film in which at least one selected from the above are dispersed, and the hardness of the first wear mitigating layer is smaller than the hardness of the second wear mitigating layer. A combination of a disc master and a mold for disc molding.