JPH0421257B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to the production of reproduction materials in which video, audio, or other information signals are recorded in the form of irregularities on the surface;
The present invention relates to an information recording stamper used for manufacturing replicas on which track grooves are formed.

Structure of Conventional Example and Its Problems FIG. 1A is a plan view of a conventional information recording stamper, and FIG. 1B is a cross-sectional view of a main part thereof.

Typically, in the case of an information recording stamper, a cleaned glass master is coated with photoresist, and then the glass master is placed on a rotating table and exposed to laser light.
During this exposure, if the linear velocity of rotation of the rotary table is constant, the laser output is also kept constant, and if the angular velocity is constant, the laser output is increased in proportion to the linear velocity, and in both cases, exposure is carried out with the aperture of the laser beam kept constant. Next, after forming uneven pit row signals or track grooves on the surface by development processing, nickel is sputtered onto the surface to form a nickel thin film, or a silver mirror reaction is performed to form a silver thin film, and nickel electrolysis is performed. The metal layer is thickened by plating and peeled off to form a master stamper for recording information. Furthermore, nickel electrolytic plating is applied to the pit row signal or track groove forming surface of the information recording master stamper, and the stamp is peeled off to be used as the information recording mother stamper.
Furthermore, nickel electrolytic plating is performed on the pit row signal or track groove forming surface of the information recording mother stamper, and this is peeled off to produce an information recording stamper.

However, the information recording stamper produced in this manner has the following problems.

First of all, when a replica is produced by a method such as injection molding, compression molding, or injection compression molding, as shown in FIG. Middle 4, outer 5
Since the pit row signal width or track groove width of the outer circumference 5 is made uniform over the entire surface, the pit signal width or track groove width of the outer circumference 5 becomes narrower than that of the inner circumference 3 due to shrinkage of the replica due to molding. but,
The track width is three to four times the pit row signal width or track groove width, so it can be almost ignored.
Second, the electrical characteristics change depending on the pit row signal width or the track groove width. Third
, the number of defective products increases. Fourth, it increases costs.

Purpose of the Invention It is an object of the present invention to adjust the width of the uneven pit row signal or track groove width on the surface of a stamper for information recording to a directly proportional relationship between the shrinkage rate and the radius, which is determined by the material of the replica and the molding conditions. The purpose is to make the width of the pit row signal or the width of the track groove uniform over the entire surface of the manufactured replica by changing the pitch continuously, thereby eliminating the above-mentioned drawbacks.

Structure of the Invention In an information recording stamper that forms uneven pit row signals or track grooves on its surface,
By continuously changing the width of the pit row signal or the width of the track groove in a direct proportional relationship between the shrinkage rate and radius determined by the material of the replica and the molding conditions, injection molding, compression molding, injection compression, etc. The width of the pit row signal or the width of the track groove of a replica formed by molding or the like becomes uniform over the entire surface after shrinkage due to molding.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2a is a plan view of an information recording stamper according to an embodiment of the present invention, and FIG. 2b is a sectional view of a main part thereof. As before, photoresist was applied onto the cleaned glass master. Next, the glass master disk was placed on a rotating table and exposed to light using a helium-cadmium laser. During that exposure,
When the rotary table is rotated at a constant linear speed, the exposure is performed from the inner circumference to the outer circumference, polycarbonate resin is used as the material of the copy, and injection molding is used as the molding method, the shrinkage rate of the produced copy is is 0.5%
Therefore, in accordance with this, the aperture lens (objective lens) for the laser beam is gradually brought closer to the glass substrate from the inner circumference to the outer circumference, and the aperture diameter is determined by the direct proportional relationship between the shrinkage rate of 0.5% and the radius. Exposure was carried out while enlarging the image. The subsequent process is similar to the conventional method, in which uneven pit array signals are formed through development processing, a nickel thin film is formed on the surface using a nickel sputter, and a master stamper for information recording is formed using nickel electrolytic plating. A mother stamper for recording and a stamper for information recording were produced.

In the information recording stamper manufactured as described above, the pit row signal width of the pit row signal section 6 is successively widened from the inner pit row signal section 7, the intermediate pit row signal 8, and the outer pit row signal 9. As a result, the width of the pit row signal of the replica is the same as that of the entire surface after shrinkage due to molding. The electrical characteristics became uniform, and there was almost no difference in the electrical characteristics between the inner and outer circumferences.

As another example, the following was performed.

Most of the steps were performed in the same manner as in the above example,
Only during exposure, instead of increasing the aperture diameter of the laser beam from the inner circumference to the outer circumference due to the direct proportional relationship between the shrinkage rate of 0.5% accompanying the molding of the replica and the radius, exposure is performed while increasing the laser output. was created. The results were similar to the above examples.

In the above example, during exposure, the rotating table on which the glass master was mounted was rotated at a constant linear velocity.
The present invention is not limited to this, and similar results can be obtained even in rotation at a constant angular velocity. In addition, injection molding was used as the molding method, and polycarbonate resin was used as the material for the replica, but other molding methods (such as compression molding and injection compression molding) in which the replica shrinks during molding and materials (such as acrylic resin, Similar results can be obtained with mixtures of vinyl chloride and carbon powder (such as mixtures of vinyl chloride and carbon powder).

Effects of the Invention As is clear from the above description, the present invention is capable of duplicating the width of a pit row signal or the width of a track groove of an information recording stamper that forms uneven pit row signals on a surface or track grooves. body materials,
The width of the pit row signal and the width of the track groove of the replica after shrinkage due to molding are changed continuously according to the proportional relationship between the shrinkage rate and the radius determined by the molding conditions. An excellent effect of uniformity over the entire surface can be obtained. As a result, it is possible to obtain the effect that there is no change in electrical characteristics between the inner and outer circumferences. In addition, the defective rate due to changes in electrical characteristics is reduced, and costs are also reduced.

[Brief explanation of drawings]

FIG. 1a is a plan view of a conventional information recording stamper, FIG. 1b is a cross-sectional view of a main part thereof, FIG. 2a is a plan view of an information recording stamper of the present invention, and FIG. 2b
is a sectional view of the main part thereof. DESCRIPTION OF SYMBOLS 1...Pit row signal part without pits, 2...Pit row signal part of a conventional information recording stamper, 3...Pit row signal of the inner peripheral part of a conventional information recording stamper, 4
. . . Pit row signal on the middle circumference of the conventional information recording stamper, 5 . . . Pit row signal on the outer periphery of the conventional information recording stamper, 6 . ...Pit row signal of the inner peripheral part of the information recording stamper of the present invention, 8...
Pit row signal at the middle circumference of the information recording stamper of the present invention, 9... Pit row signal at the outer circumference of the information recording stamper of the present invention.

Claims (1)

[Claims] 1. The width of the uneven pit row signal or track groove formed on the surface is continuously changed in accordance with the direct proportional relationship between the shrinkage rate and the radius, which is determined by the material of the replica and the molding conditions. A stamper for recording information.