JPH05101449A - Reproducing method for optical disk - Google Patents

Abstract

PURPOSE:To execute transfer without contg. bubbles while maintaining high productivity in spite of presence of some ruggedness in a transparent resin substrate, etc. CONSTITUTION:A pressurizing plate 10 having a prescribed curvature is used, by which a substrate 2 consisting of a transparent resin is inserted in a sandwich form with this pressurizing plate and a stamper 8 and the stamper 8 is brought into local pressurized tight contact with a radiation curing resin 6 in the method for reproducing the optical disk by bringing the stamper 8 into pressurized contact with the radiation curing resin 6 formed on the substrate 2. The pressurized tight contact part 14 is gradually moved by moving the above- mentioned pressurizing plate 10, etc., by which the bubbles contained in the contact surface are expelled to the outside. The parts where the pressurized tight contact is completed are irradiated with radiations to completely cure the radiation curing resin. The half curing and complete curing treatments are executed continuously if the resin 6 prior to the pressurized tight contact is put into a half-cured state by irradiating this resin with the radiations of the slight quantity from the same radiation source as the radiation source used at the time of the curing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a read-only disc on which information is recorded such as a video disc, a digital audio disc, a document file disc, a disc having a groove for a recordable / rewritable disc, or a part of the disc. The present invention relates to a read-only optical disk duplication method.

[0002]

2. Description of the Related Art Conventionally, an injection molding method, a cast molding method and the like have been known as a method of copying an optical disc on which information is recorded. The injection molding method is a method in which a thermoplastic resin melted at a high temperature is injected and injected into a mold cavity at a high pressure, and then the mold is cooled and molded. This injection molding method is widely used because the process is simple and the material usage efficiency is high, and under the appropriate conditions, the pits, which are the signals of the optical disc of the stamper, which are minute unevenness signals, can be transferred under appropriate conditions. However, since this injection molding method is a process under high temperature and high pressure, the manufacturing equipment is large-scale and expensive, and since the heating and cooling are repeated, the heat quantity of the mold that withstands high temperature and high pressure is small. However, there is a problem that it is difficult to shorten the molding cycle.

On the other hand, the above-mentioned cast molding method is a molding method in which a radiation curable resin is pressure-bonded to a stamper and is irradiated with radiation to cure the resin. However, this method is not a temperature cycle but is a liquid depending on the radiation dose to be irradiated. In order to solidify the material, the time required for this phase change can be made extremely shorter than the conventional injection molding time by increasing the radiation dose, and as the conventional injection molding method shortens the molding cycle, However, there is a problem that the transferability, especially the transferability in the outer peripheral portion of the optical disc is deteriorated, or the deformation occurs due to the internal strain. It is easy to have a configuration that is not affected by internal distortion.

[0004]

By the way, in recent years, optical discs on which various types of information are recorded or which can be recorded have a tendency to be produced in small quantities and in a large variety of products. As a production system therefor, production management is easy, Moreover, single-wafer production systems with short lead times are receiving attention. In this production system, it is required that the individual processes be synchronized and have high speed and high reliability. However, the above-mentioned cast molding method using a radiation curable resin having good transferability will reduce productivity in the molding process. There were the following drawbacks. That is, in the conventional cast molding method using a radiation curable resin, a liquid radiation curable resin is injected or dropped between the stamper and the transparent substrate, and then these are pressed to spread the radiation curable resin thinly, and thereafter, Ultraviolet rays were irradiated from the substrate side to cure.

However, in the method of bringing the liquid resin into close contact with the stamper to cure it, in order to separate the substrate, which is integrated with the radiation-curable resin having the uneven pits or grooves transferred to the surface after the curing, from the stamper, It was necessary to perform the treatment slowly so that there was no residue on the stamper, and to prevent the substrate from being destroyed, the substrate was bent with a small force so that the peeling point gradually moved on the peeling surface. Therefore, in such a conventional method, a step of injecting or dropping a radiation curable resin between the transparent substrate and the stamper to spread the pressure, a step of irradiating with radiation and curing, and a step of peeling the substrate from the stamper are performed. The productivity was extremely poor because they were all performed on the same stage.

Therefore, the present inventor has devised a method for improving productivity by separating the above steps. In this method, a radiation-curable resin is applied in a semi-cured state on a transparent substrate in advance, and then a stamper is pressure-bonded to the semi-cured radiation-cured resin surface to transfer pits or grooves.
Further, in this method, a resin having excellent adhesion to the transparent substrate can be used, and since it is in a semi-cured state, the peelability from the stamper is relatively good.

However, in the above-mentioned method of pressing the entire surface in the flat plate state, when the stamper is pressed to the radiation-cured resin in the semi-cured state, the bubbles contained in the pressure-bonded surface are not good if the flatness of the pressure-bonded surface is not good. Will deteriorate the transfer of the uneven signal of the stamper. In practice, in order to obtain excellent flatness that does not contain air bubbles, it is necessary to cut out or punch out from a flat plate with excellent flatness as a transparent resin substrate. In this case, create a transparent resin substrate. The cost for doing so is high, and the advantages of high-speed production to obtain high productivity are lost. The present invention has been made to pay attention to the above problems and to solve them effectively. It is an object of the present invention to provide a method of duplicating an optical disc that can perform transfer without bubbles while maintaining high productivity even if the transparent resin substrate or the like has some irregularities.

[0008]

In order to solve the above-mentioned problems, the present invention provides a method of copying an optical disk by pressing a stamper onto a radiation-curing resin formed on a substrate, wherein the stamper and the radiation-curing resin are used. The resin is locally pressure-adhered, and the pressure-adhered portion is moved from one side of the radiation-curable resin to the other side, and radiation is applied to the radiation-cured resin that has been pressure-adhered. It is configured to include a step of irradiating. Further, in the embodiment according to claim 2, the above-mentioned configuration includes a step of irradiating the radiation curable resin before reaching the pressure contact with a weak amount of radiation to bring the radiation curable resin into a semi-cured state. It is the one.

[0009]

Since the present invention is configured as described above, the stamper and the radiation curable resin are locally pressure-adhered to each other, and this pressure-adhered portion gradually moves, resulting in the contact surface. The contained bubbles are expelled to the outside, and even if there are some irregularities on the substrate or the like, good signal transfer can be performed without being affected by this. In particular, by irradiating the radiation curable resin immediately before pressure contact with a weak amount of radiation, the radiation curable resin can be brought into a semi-cured state, and the step of forming the semi-cured state, the transfer step and the peeling step are performed in one continuous step. It can be carried out.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical disk duplicating method according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is an explanatory view showing a state in which a transfer operation is being performed by using the first embodiment of the method of the present invention, and FIG. 2 is a sectional view showing a substrate and a radiation curable resin before starting the transfer operation. As shown in the figure, 2 is a substrate made of a radiation transparent material formed in a circular flat plate shape, and a central hole 4 for alignment is formed in the central portion of the radiation transparent substrate 2. The radiation transmissive substrate 2 is made of, for example, a transparent resin in order to transmit radiation. Here, the radiation includes not only electromagnetic waves in the range of ultraviolet rays to infrared rays but also electromagnetic waves having a short wavelength such as γ rays and particle beams such as electron beams.

First, as shown in FIG. 2, in the first embodiment of the present invention, on the upper surface of the radiation transmissive substrate 2,
The radiation curable resin 6 is applied in a ring shape. The applied portion is only the area to which the pits, grooves, etc., which are information signals, are to be transferred, and an effective means therefor is, for example, a printing method. In this printing method, for example, as a screen used in the case of screen printing, a screen having a high mesh number, a wire having a small diameter, or preferably a metal sheet which has been subjected to surface treatment by etching into an appropriate pattern, It is preferable that the resin surface after printing is flat. This resin surface is made smooth by a heating roller or the like, if necessary. Further, as the radiation curable resin 6, a thin film can be obtained by using a resin having a low viscosity, so that the amount of warpage can be reduced. As a method for obtaining a thin coating film having a smooth surface, a spray method may be used instead. For example, when a radiation-curable resin having a viscosity of 10 to 50 centipoise is spray-coated on the radiation-transparent substrate 2 where only the information area is exposed by masking, unlike the case of screen printing, the radiation-transparent substrate surface comes into contact. Because there is nothing,
There is an advantage that the bonding surface between the radiation curable resin 6 and the radiation transmissive substrate 2 can be cleaned and the bonding can be performed firmly.

Next, as a radiation from the coating surface 2a of the radiation-curable resin 6 of the radiation transmissive substrate 2, that is, the back surface of the stamper when viewed from the transfer surface of the stamper, for example, ultraviolet rays (not shown).
Irradiate. This ultraviolet ray passes through the radiation transparent substrate 2 and is absorbed by the radiation curable resin 6. At this time, the amount of ultraviolet rays to be irradiated is set so that the radiation curable resin 6 is in a semi-cured state in which the resin 6 still has viscosity. After the semi-curing operation of the resin is performed in this manner, the transfer and peeling operations of the stamper are then performed as shown in FIG. First, the stamper 8 is brought into contact with the substrate 2 coated with the radiation-curable resin 6 in a semi-cured state, and in this state, the pressure plate 10 having an arc-shaped cross section made of a transparent material that transmits radiation. Hang on. The pressure plate 10 is not a flat plate like a conventional device, but a curved surface having a predetermined radius of curvature,
That is, it has a cross-sectional shape that constitutes a part of the roller, and a local pressure P can be applied toward the substrate 2 at the contact portion 12 between the roller and the substrate 2. And
The pressure plate 10 moves in the circumferential direction of the roller while applying pressure to the substrate 2.

On the other hand, the stamper 8 is fixed to a rigid block (not shown), and the entire stamper 8 is moved in the horizontal direction in synchronization with the movement of the pressure plate 10. Therefore, the substrate 2 sandwiched between the stamper 8 and the pressure plate 10 has a contact portion 1 with the pressure plate 10.
2 undergoes local deformation, resulting in stamper 8
The radiation-curable resin 6 and the radiation-curable resin 6 are locally pressure-bonded to each other to form a pressure-bonded portion 14. In this case, it is desirable that the pressure force per unit area of the pressure contact portion 14 be higher than the pressure force at the time of pressure compression according to the conventional method. The pressure contact portion 14 is
The pressure plate 10 is formed linearly in the longitudinal direction, that is, in the direction perpendicular to the plane of the drawing, and the stamper 8 and the pressure plate 10 are formed.
With the movement of the radiation curing resin 6, the radiation curing resin 6 moves from one side portion to the other side portion. In this case, the moving mechanism (not shown) for moving the stamper 8 and the pressure plate 10 is surely synchronized with each other, and the positional deviation between the stamper 8 and the substrate 2 is prevented. ..

Further, the radiation curable resin 6 which is locally pressure-bonded by the pressure contact portion 14 is irradiated with ultraviolet rays 18 as radiation from below. At this time, a light-shielding plate 20 made of a radiopaque material is provided along the inner side of the pressure plate 10 in order to define a region to be irradiated with radiation, and its end portion is in contact portion 12 with the substrate. It is located correspondingly. Therefore, the radiation curing resin 6 located on the moving direction side of the stamper 8 and the pressure plate 10 from the contact portion 12, that is, only the portion where the pressure contact operation of the radiation curing resin 6 is completed, is irradiated and is completely cured. Therefore, the unevenness signal 1 as information previously formed on the lower surface of the stamper 8
In particular, 6 is reliably reverse-transferred at the pressure contact portion 14. In this case, the radiation curable resin 6 starts to be cured at the same time as the pressure contact between the convex curved pressure plate 10 and the flat stamper 8 or immediately after the pressure contact. The shape of the pressure-contacting portion 14 is linear as described above, and the cured portion moves in the direction orthogonal to the length direction. However, because of such linear pressure-contacting shape. In addition, the bubbles contained in the contact surface between the stamper 8 and the radiation curable resin 6 are easily expelled in the direction orthogonal to the lengthwise direction of the linear pressure-contacting portion 14, so that the pressure-tightness is reduced. Dresser 14
No air bubbles remain inside.

Further, even if there is some unevenness on the transfer surface of the radiation curable resin 6 etc. before the information transfer, the stamper 8 and the radiation curable resin 6 are locally pressed and brought into close contact with each other. Since the attachment portion 14 is sequentially moved, a non-contact portion does not occur between the stamper and the transfer surface of the radiation curable resin, and the uneven signal can be reliably transferred. Particularly, in a high-speed process in which the method of the present invention is carried out, an inexpensive substrate 2 can be obtained by multi-stage injection molding.
Can be supplied. In this case, since the substrate is injection-molded at a high speed, the flatness tends to be deteriorated. However, by moving the pressure contact portion 14 to which the pressure is locally applied as described above, the entire surface is pressure-bonded. It is possible to prevent the unevenness of the substrate from adversely affecting the transfer of information.

When the pressure-bonding operation and the curing operation are completed in this way, the stamper 8 and the radiation-curable resin 6 are peeled off, and the copying operation is completed. In this case, since the radiation-curable resin 6 in the semi-cured state and the stamper 8 are pressure-bonded to each other as described above, the releasability between them is good, and therefore the peeling operation can be performed quickly. The property is improved. In the above embodiment, the stamper 8 has a flat plate shape and the pressure plate 10 has a curved surface shape. However, these relationships may be reversed as shown in FIG. 3, those parts which are the same as those corresponding parts in FIG. 1 are designated by the same reference numerals. That is, in FIG. 3, the stamper 8 is formed in a convex curved surface shape having substantially the same curvature as that of the pressure plate 10 shown in FIG. 1, and the uneven signal 16 is formed on the surface thereof. On the other hand, the transparent pressure plate 10 that supports the radiation transmissive substrate 2 is formed in a flat plate shape and holds the substrate 2 by suction.

The light shielding plate 20 is also formed in a flat plate shape so as to correspond to the shape of the pressure plate 10. When the method of the present invention is carried out based on the apparatus configured as described above, in order to move the linear pressure contact portion 14, the pressure plate 10 is moved in the horizontal direction, but the stamper 8 has a curved surface. Since the radiation-curable resin 6 is moved in the circumferential direction, after the radiation-curable resin 6 is cured by the ultraviolet rays 18, the radiation-curable resin 6 is automatically separated from the curved stamper 8 with the movement of the pressure contact portion 14. That is, in the case of the embodiment shown in FIG. 3, since the transfer of information containing no bubbles in the linear pressure contact portion 14 and the curing and the peeling of the substrate 2 from the stamper 8 are continuously performed, it is extremely productive. It is possible to improve the sex. In the above-described embodiment, the radiation-curable resin is semi-cured and the stamper is pressure-bonded with the radiation-curable resin in order to improve the releasability, but the radiation-curable resin and the stamper are not semi-cured. Needless to say, they may be crimped.

In the first embodiment, the radiation-curable resin is semi-cured in another device (not shown), and then,
Although the transfer is performed by the stamper device, the semi-curing operation of the radiation curable resin may be performed by the stamper device as shown in FIGS. 4 to 5. FIG. 4 is an explanatory view for explaining a second embodiment of the method of the present invention, and FIG. 5 is an enlarged view showing a main part of the stamper device shown in FIG. still,
The same parts as those shown in FIGS. 1 and 2 are designated by the same reference numerals. In this embodiment, the stamper 8 is made of a flexible material as in the previous embodiment, and the stamper 8 is
A stamper holding block 22 made of a rigid material whose surface is formed into an arc shape so as to structurally endure under pressure and pressure.
It is installed along the arc surface of. A roller 24 is provided above the block 22 as a pressing means for pressing the substrate 2 made of a transparent resin material transparent to ultraviolet rays between the block 22 and the block 22. The surface 26 is made of a metal that is mirror-polished to reflect the ultraviolet rays 18 as radiation as described later.

First, a radiation curable resin 6 which is cured by ultraviolet rays like an ultraviolet curable resin is applied to the surface of the circular substrate 2. As the radiation curable resin 6, a resin having a low viscosity of about 10 to 50 centipoise (cps) and relatively good fluidity is used as in the above-mentioned embodiment. This facilitates the elimination of bubbles when the resin 6 and the stamper 8 are pressure-bonded. Further, as a method of applying the radiation curable resin 6 on the substrate, a printing method is used as in the above embodiment, and a thickness of 1
Make a thin coating film of about 10 μm. Only the part with the pattern to be transferred is printed, so that there is no excess of radiation-curable resin, and during pressurization this excess is cured by UV irradiation to generate burrs, and burrs damage the stamper. Alternatively, it is possible to prevent the occurrence of defects such as pinholes during the processing of the reflective film in the subsequent process.

When the application of the radiation curable resin 6 is completed, the substrate 2 is sandwiched between the roller 24 and the stamper 8 with the resin surface facing the stamper 8 side, and the roller 24 and the stamper are pressed together under pressure. The holding block 22 is synchronously moved in the direction of the arrow B, and at the same time, the ultraviolet ray 18 is irradiated toward the transparent substrate 2 from above the substrate 2 in the feeding direction. In this case, the roller 24 or the stamper holding block 22 may be moved up and down relative to each other or the block 22 may be rotated in accordance with the feeding of the substrate 2 so that a constant pressure is always applied to the substrate 2. .. Here, it can be divided into three zones of X, Y and Z depending on the state of the radiation curable resin 6 which receives the ultraviolet rays 18.

In the X zone, the radiation curable resin 6 has not yet been pressed just before being pressed, and the ultraviolet rays 18 which have been irradiated have an intensity of about 1. between the stamper surface 28 and the roller surface 26. Radiation in this X zone is reflected during a distance of about 2 mm, that is, between the surface 26 of the metal roller 24 whose surface is mirror-polished and the surface 28 of the stamper 8 and the surface 30 of the transparent resin substrate 2 to become a weak amount. Reaching the cured resin 6,
The resin is semi-cured. In order to obtain such a resin in a semi-cured state, about 1 to 30% of the amount of ultraviolet rays necessary for the complete curing of the resin is sufficient, and this can be achieved by appropriately adjusting the direction A for irradiating the ultraviolet rays 18. It is possible.
Further, the Y zone is a pressure curing zone, and in this zone, the radiation curing resin 6 is used for the roller 24 and the stamper 2.
At the same time as being pressure-bonded to and from the laser beam 8, a considerable amount of ultraviolet rays 18 are received, and the uneven signal of the stamper 28 is transferred here.

Further, the Z zone is a resin peeling zone. In this portion, the pressure is released, and the surface of the radiation curable resin 6 to which the uneven signal of the stamper has been transferred is made into a convex curved surface. The peeling occurs due to the shearing stress of the substrate 2 received by the stamper surface 28, and the shearing force is released at the same time as the peeling. Also, since a large amount of ultraviolet rays 18 are irradiated, the radiation curable resin 6 is in this Z zone. It is completely cured. In this way, each member
When the transfer is completed and the transfer is completed over the entire surface, the transfer of the information-transferred substrate from the stamper 8 is also completed. The clamping area in the vicinity is held, and this is carried to the next step, for example, the reflective film processing step.

As described above, since the step for obtaining the semi-cured state of the radiation curable resin and the pressurizing step are continuously performed, it is possible to simplify the entire transfer step.
Further, since the ultraviolet ray 18 emitted from one ultraviolet ray source can obtain the completely cured state and the semi-cured state of the radiation curable resin, it is possible to simplify this without complicating the equipment. In the above-mentioned embodiment, the ultraviolet rays for making the radiation curable resin 6 in the semi-cured state are about 1.2 mm between the stamper surface 28 and the roller surface 26.
Since the resin is irradiated through the transparent substrate 2 having a certain thickness, if the moving speed of the member in the direction of the arrow B is increased for the purpose of improving the productivity, the amount of ultraviolet rays for the semi-cured state will be sufficient. It becomes impossible to secure it. Therefore, FIG.
In order to solve this problem as shown in FIG. 8, it is possible to widen the transparent interval of the pressurizing section and increase the amount of ultraviolet rays passing therethrough to speed up the process.

That is, in the roller 24 shown in FIG. 6, an ultraviolet-transparent hard material having an appropriate thickness, for example, quartz glass 32 is formed into an annular shape to form the whole, and the inner surface of the quartz glass 32 is formed. A reflective film 34 that reflects ultraviolet rays is formed on the surface of the substrate. In this case, the reflecting surface of the ultraviolet rays 18 is not the roller surface but the reflecting film 34 inside the roller, and therefore the distance D through which ultraviolet rays pass or is transmitted is substantially widened. Therefore, the amount of ultraviolet rays passing through to obtain the semi-cured state increases, and the resin can be semi-cured in a short time to speed up the process. In the structure shown in FIG. 6, a transparent film having a reflecting film on one side or a transparent film laminated on a mirror-finished metal strip is wound around a roller portion or used as a belt. Is also possible.

When the transparent quartz glass 32 is used as the roller 24 as shown in FIG. 7, the diameter R of the central shaft 38 whose surface is mirror-polished is appropriately changed from zero to the inner diameter of the roller. By doing so, it becomes possible to adjust the ultraviolet ray amount under appropriate curing conditions and semi-curing conditions. Further, as shown in FIG.
When used as 4, the shape of the central shaft 38 is not a circular cross section as shown in FIG. 7, but is, for example, a substantially semicircular cross section, and a mirror angle adjusting mechanism (not shown) is connected to the central shaft 38. However, by changing the shape or direction of the mirror surface 40, it is possible to adjust the amount of ultraviolet rays under appropriate curing conditions and semi-curing conditions. In particular, in the structure shown in FIG. 8, it is possible to automatically adjust to appropriate curing conditions and semi-curing conditions by feeding back the change in the amount of light to the mirror angle adjusting mechanism even if the ultraviolet intensity changes. ..

[0026]

As described above, according to the present invention, the following excellent operational effects can be exhibited. Since the stamper and the radiation curable resin are locally brought into pressure contact with each other and the pressure contact portion is moved, the bubbles contained in the contact surface can be reliably removed to the outside. Also,
Even if there is some unevenness on the transfer surface of the radiation curable resin, the transfer surface and the stamper can be surely brought into intimate contact with each other over the entire surface. Therefore, the transfer quality can be improved and the yield and the productivity can be improved. Can be improved. In particular, when a curved stamper is used, transfer, curing and peeling can be continuously performed, so that productivity can be further improved. Furthermore, when the process of making a semi-cured state of the resin and the transfer pressurizing process are consecutively performed, not only can the process as a whole be greatly simplified, but also an ultraviolet source for both processes can be used. It can be used in common and the equipment can be greatly simplified.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining a first embodiment of an optical disc duplicating method according to the present invention.

FIG. 2 is a cross-sectional view showing a state in which a radiation curable resin is applied to a substrate.

FIG. 3 is an explanatory diagram for explaining another embodiment of the present invention.

FIG. 4 is an explanatory diagram for explaining a second embodiment of the present invention.

5 is an enlarged view of a main part showing a main part in FIG.

FIG. 6 is an explanatory diagram for explaining a modification of the second embodiment of the present invention.

FIG. 7 is an explanatory diagram for explaining another modification of the second embodiment of the present invention.

FIG. 8 is an explanatory diagram for explaining still another modification of the second embodiment of the present invention.

[Explanation of symbols]

2 ... Substrate, 6 ... Radiation curable resin, 8 ... Stamper, 10 ...
Pressure plate, 12 ... Contact portion, 14 ... Pressure contact portion, 16 ... Concavo-convex signal, 18 ... Ultraviolet ray (radiation), 20 ... Light shielding plate, 22 ...
Stamper holding block, 24 ... Roller, 26 ... Roller surface, 28 ... Stamper surface, 32 ... Quartz glass, 34 ... Reflective film, 38 ... Central axis, 40 ... Mirror surface portion, D ... Interval.

Claims (2)

[Claims] 1. A method of replicating an optical disk by press-bonding a stamper to a radiation-curable resin formed on a substrate, wherein the stamper and the radiation-curable resin are locally pressure-bonded to each other, and the pressure-bonded portion is bonded. Of the radiation curable resin from one side to the other side, and irradiating the radiation curable resin, which has been pressure-bonded, with radiation. Method. 2. The method according to claim 1, further comprising a step of irradiating the radiation curable resin with a weak amount of radiation before the pressure contact to bring the radiation curable resin into a semi-cured state. 1. The method for copying an optical disc according to 1.