JPH0344841A - Method and device for manufacturing optical recording medium - Google Patents

Abstract

PURPOSE:To prevent intrusion of dust in the production process and to produce the medium at low cost by successively extruding molten resin into a strip to form a resin sheet, coating the sheet with UV-curing resin, transferring a rugged preformat pattern thereon, forming a recording layer and protective member thereon and cutting the sheet into the optical recording medium. CONSTITUTION:The source resin is molten and extruded into a strip to form a resin sheet 16, coated with light-curing resin 21, and pressed with a roller 18 having a rugged preformat pattern while irradiating light 19 to cure the light-curing resin 21 to transfer the preformat pattern. Then, a recording layer in which information is recorded or/and reproduced is formed on the preformat- formed surface of the resin sheet 16 by coating, and a protective member 9 is formed on the recording layer. The resin sheet 16 having the recording layer and the protective member 9 is then cut into an optical recording medium 15. These processes are sequentially perforemd, which avoids deposition of dust which may cause errors in the medium. Thus, low production cost can be realized and the obtd. optical recording medium has high reliability.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention comprises the steps of forming a concavo-convex pattern such as track grooves and addresses on a substrate, forming a recording layer thereon, and further forming a protective layer thereon. The present invention relates to a continuous method and apparatus for manufacturing an optical recording medium.

[Conventional technology]

Conventionally, in order to manufacture optical recording media such as optical disks and optical cards, in order to form tracks and addresses, injection equipment, compression equipment, photocuring molding using photopolymer, or casting molding using thermosetting resin are used. etc. have been used. Further, a spinner is used for forming the recording layer on a coating-type recording medium in which film formation is performed using vacuum evaporation or sputtering. In addition, bonding of protective members and coating of a protective film have been used to form the protective member. These techniques have been selectively used depending on the required recording medium.

However, in the conventional individual technology selection for each process as described above, there is no consistency in the process, so a stocker is installed to connect the processes, and often long periods of residence in this stocker are required. This method has drawbacks such as poor productivity and reduced reliability due to dust adhesion and contamination.

Particularly in the case of substrate molding by injection, which has been commonly used in the past, since each substrate is molded by injection, it is necessary to process each substrate one by one in subsequent steps. For example, when forming a recording material, in the case of an inorganic recording medium, each sheet is attached to a sample stage of a sputtering device or a vapor deposition device, and when a recording film is formed, it is removed one by one and stored in a stocker.

Even with coated organic recording media, it is necessary to repeat the process one by one using a spinner, making the process complicated and long. This is extremely disadvantageous in optical recording, where even the slightest amount of dust attached affects the reliability. As a countermeasure to this problem, attempts have been made to avoid manufacturing in extremely clean rooms and manual labor by people who are likely to introduce dust, and to automate the process using automatic hands, etc. However, these methods have the disadvantage of increasing equipment costs. was. A similar problem also occurs in the process of providing a protective member.

Since writing and reading are performed on the surface of the recording medium using a semiconductor laser spot narrowed to about 1 μm, the time and spatial distance required to protect the recording surface must be the minimum necessary.

On the other hand, as a conventional manufacturing method for continuous optical recording media, Japanese Patent Publication No. 63-31847 discloses that a UV-curable resin layer is provided on a base film, and signals are transferred and cured using a stamper to continuously manufacture flexible disks. A manufacturing method is disclosed.

However, in this method, the base film is wound up into a roll and this is fed into the equipment, but when the base film is manufactured and rolled up, dust tends to adhere to the substrate surface, and the manufactured disc There was a problem with dust getting inside.

Further, in order to remove dust on the surface of the substrate, for example, solvent cleaning is required, and a solvent cleaning process and a drying process are essential, which has the disadvantage of complicating the process and increasing cost.

Furthermore, in Japanese Patent Application Laid-Open No. 62-71040, a radiation-curable resin is coated on a long synthetic polymer film substrate, exposed to light or irradiated with an electron beam, and after development, a radiation-curable resin mainly containing an organic dye is applied. A method for continuously forming a recording layer and continuously molding an optical recording medium is disclosed.

However, this method requires development, which complicates the process, and when an organic dye recording layer is subsequently formed, there is a risk that the developer may have an adverse effect on the formation of the recording layer.

Specifically, if the developer remains on the recording layer forming surface, for example between the grooves, when the recording layer is applied there, the concentration of the coating solution changes in that area, making it difficult to control the thickness of the recording layer. There is a risk that the dissolved radiation-curable resin may deteriorate the organic dye in the recording layer.

(Problems to be Solved by the Invention) The present invention has been made in view of these conventional problems, and provides an optical recording medium such as an optical disk or an optical card that has excellent mass productivity, low cost, and high reliability. It is an object of the present invention to provide a method for manufacturing an optical recording medium that can obtain the following.

[Means for solving problems]

That is, the method for manufacturing an optical recording medium of the present invention includes a step of melting and extruding a resin to form a molten resin sheet, a step of applying a photocurable resin onto the resin sheet, and a step of applying the resin sheet to a roller having a concave-convex preformat pattern. a step of transferring the uneven preformat to the coating film of the photocurable resin by pressing and irradiating with light; recording information on the uneven preformat forming surface of the resin sheet on which the uneven preformat is formed by irradiating light; and/or Alternatively, a step of forming a reproducible recording layer by coating, a step of forming a protective member on the surface on which the recording layer is formed, and a step of cutting the resin sheet having the recording layer and the protective member into individual recording media are performed continuously. It is characterized by having the following characteristics.

The optical recording medium manufacturing apparatus of the present invention also includes a means for melting and extruding a resin to form a molten resin sheet, a means for applying a photocurable resin onto the resin sheet, and a means for coating the photocurable resin on the resin sheet. means for transferring the rugged preformat to the membrane;
means for forming a recording layer capable of recording and/or reproducing information by irradiating light on the uneven preformatted surface of the resin sheet on which the uneven preformat is formed; forming a protective member on the forming surface of the recording layer; The present invention is characterized in that it continuously includes means for cutting the resin sheet having the #3 layer and the protective member into individual recording media.

That is, according to the present invention, a resin sheet is formed by extruding a molten resin into a belt shape, and then an ultraviolet curable resin is applied.
Transferring the uneven preformat to the coating film, and further recording layer,
Since the formation of the protective member and the cutting of the optical recording medium are performed continuously, the intrusion of dust can be suppressed, and an optical recording medium with high reliability can be obtained.

The present invention will be explained in detail below using the drawings.

FIG. 1 is a schematic diagram of an apparatus showing an embodiment of the present invention.

Reference numeral 1 denotes an extruder (hereinafter abbreviated as Ruder), into which a pellet serving as a substrate material is fed from a hopper 11. A T-die 12 connected to the ruler extrudes the melted resin in a band shape. The resin is guided between the gap between the rollers 2 and 3 near the discharge port of the T-die, and the mirror surface is transferred to the lower surface of the resin sheet 16 by the mirror roller 3, and then the mirror surface is transferred to the other side of the resin sheet by the mirror roller 4. A mirror surface is also transferred to the surface, forming a flat sheet. This resin sheet 16 is coated with a photocurable resin 21 by a coater 17, and then pressed against a stand bar roll 18 having an uneven preformat pattern on its surface, and the pressed portion is irradiated with an ultraviolet lamp 19 to form a photocurable resin coating. A concavo-convex preformat pattern for track grooves and address pits is transferred to the recording medium.

Here, the molten resin sheet extruded from the T-die 12 is pressed between the rollers 2 and 3 to form a mirror surface on the surface.
At this time, it is preferable for the resin sheet to be in a very close to molten state in order to perform good transfer. Therefore, the distance between the T-die 12 and the pressing point between the rollers 2 and 3 is preferably 50 cm or less, particularly 20 cm or less, and The temperature of the surrounding atmosphere during this time is preferably 60° C. or higher.

Furthermore, the thickness of the resin sheet of the present invention can be varied by changing the distance between the rollers 2 and 3, but the resin sheet has almost no distortion inside it, and the uneven preformat transferability is good. The thickness of the resin sheet is 0.2mm~
It is preferably 2.0 mm, particularly 0.3 mm to 1.5 mm.

If the thickness is less than 0.2 mm, the cooling of the resin sheet will be too fast and transfer will not be performed sufficiently; If it is more than 0 mm, distortion tends to occur within the sheet.

Furthermore, the rollers 2.degree. 3.4, which determine the thickness of the sheet, are set to be as parallel as possible to prevent uneven thickness of the sheet, which may cause recording/reproducing errors. in particular,
If the angle formed by each axis of the roller is θ, then tanθ”
It is preferably 5X10-3 or less, particularly 1X10-' or less.

In addition, the extrusion speed of the resin sheet and the stamper roll 18,
Preferably, the peripheral speeds of the mirror rolls 3, 4 and the coater 5.17 are set equal. That is, since stress such as stretching is not applied to the resin sheet, it is possible to obtain a resin sheet with excellent optical properties and no birefringence.

In the optical recording medium manufacturing method of the present invention, the stand bar roll 18 with the concave-convex preformat pattern is a nickel stamper used in the conventional manufacturing of optical recording medium substrates.
It can be created by pasting it on a mirror-polished roller, or by providing a pattern forming layer directly on the roller base material, or by forming a concavo-convex preformat pattern thereon using photolithography technology.

Next, if the speed at which the resin is extruded is too slow, the resin sheet will harden before it is shaped, resulting in poor mass production, and if it is too long, the transfer of the uneven preformat signal will become unstable, so the extrusion speed is 0.3 m/ min~4m/min, especially 1m/m
In - 3m/min is preferable.

Further, the light source intensity and irradiation distance of the ultraviolet lamp 19 used in the present invention are determined by the curing speed of the photocurable resin used and the moving speed of the resin sheet, but the light source intensity is 10 W/cm ~
30 W/cm, and the irradiation distance is preferably 1 cm to 10 cm.

Next, 5 is a coater that applies a recording layer material to this preformat forming surface. Various printing methods are used for coating, and the simplest method is to supply ink, which is a recording material dye dissolved in a specified solvent, to the ink reservoir 5' via a single roller onto the sheet surface, as shown in the figure. It becomes.

At this time, it is preferable to apply the recording layer from the bottom of the resin sheet. That is, in principle, it is possible to apply the coating on the upper surface side if the manufacturing environment is completely clean, but in reality, it is impossible to completely eliminate dust. Therefore, bottom surface application is extremely effective as a dustproof effect.

Next, the coated surface is passed through a tunnel drying oven 6 to remove the solvent, and then a protective member 9 is formed. As a protective member, (
1) A method of laminating a protective substrate or film directly on the recording layer, (2) A method of forming a protective film directly on the recording layer formation surface, (3) A method of providing an air layer on the recording layer formation surface and pasting the protective member. There are methods etc.

In Figure 1, the protective sheet 9 is fed from the roll feeder 7.
is sent, and the protective members are bonded together using pressure rollers 8 and 8'. This can be applied to the above-mentioned (1) direct bonding or (3) bonding via an air layer. The protective substrate for bonding (3) is provided with a spacer outside the recording section, and the protective member side is previously textured to maintain a predetermined air layer at the time of bonding. For this purpose, a member is used in which the surface of the protective sheet is processed into irregularities by vacuum forming and then rolled into a hoop shape. Alternatively, the unevenness may be applied to the outer periphery and/or inner periphery outside the recording section using a bead-containing adhesive and bonded. Further, as a method for directly forming the protective member on the recording layer, there is, for example, a method in which a hot melt adhesive is placed between the resin sheet and the protective member and the adhesive is bonded to each other by passing the resin sheet and the protective member through a heated roller. For bonding, in addition to bonding using an adhesive or bonding using an adhesive tape that also serves as a spacer, the substrate and the protective member may be bonded directly (8 pieces) using an ultrasonic welder or heat press.

The sheet provided with the protective member is then separated into individual optical recording media 15 by ten cutting machines. The separated optical recording medium 15 is conveyed by a conveyor belt 14. Further, the remaining material 12 after cutting the optical recording medium is wound onto a drum 13. For cutting, male/female die punching using a hydraulic press or laser cutting is used.

In the present invention, since the resin sheet is processed in a continuous state, the resin sheet itself moves until the cutting process, and therefore, the resin sheet is transported only by relatively simple feeding using rolls.

In the process of laminating the resin sheet and the protective member or punching out the optical recording medium, a mechanism for automatically performing alignment may be provided as necessary. In other words, with the backing material that provides an air layer, the position where the preformat is formed is detected when pasting is performed outside the recording section, and the position is moved left and right so that the uneven part of the backing material is in the corresponding position. Forward and backward feed adjustments are made.

In the cutting process, precision is especially required for discs, and the inner or outer circumference is detected by detecting the reflected light of a laser spot, or by COD, which detects position signals by reading groups or specially provided markers on the board. Move the punching press.

In order to perform these alignment mechanisms with the necessary degree of freedom, the sheet is fed with a certain amount of "sag". Also, the first
If the coating surface is provided on the bottom side of the sheet as shown in the figure, it is advantageous to prevent dust from adhering to the coating surface, but the conveyance roller 20 is placed on the edge of the sheet so as not to come into contact with the coating surface that will be the recording surface. A retaining roller is used.

Incidentally, the cutting of the information recording medium, which is the last step in the process shown in FIG. It is preferable that the resin sheet is stopped in order to improve cutting accuracy.

However, during melt extrusion of the resin sheet, formation of the uneven preformat, and formation of the recording layer, there may be problems such as uneven thickness of the resin sheet, distortion within the resin sheet, poor transfer of the uneven preformat, and uneven coating of the recording layer. Preferably, the resin sheet is formed and transported at a constant speed to prevent defects.

Therefore, in the present invention, it is preferable to provide a mechanism for slackening the resin sheet before the cutting step in order to continuously perform the step of feeding the resin sheet in a continuous sheet and the cutting step of stopping the resin sheet.

In FIG. 1, reference numeral 22 denotes a slackening mechanism that connects the continuous conveyance process from the resin extrusion process to the protection member lamination process and the intermittent feeding process of the cutting process by moving the roller 21 up and down with a spring. The process can be performed continuously.

Furthermore, in addition to the steps shown in FIG. 1, in order to prevent dust from adhering to the resin sheet on which the concave-convex preformat is charged, a process of neutralizing static electricity and removing dust may be inserted as appropriate.
Further, it is preferable to cover necessary parts, for example, from the melt extrusion part of the resin sheet to the process of forming the protective member, with a clean tunnel in order to prevent dust from adhering.

As the photocurable resin used in the present invention, for example, polyester acrylate, polyurethane acrylate, epoxy acrylate, polyether acrylate, etc. can be used.

Next, the resin used as the substrate material of the present invention is preferably a thermoplastic resin that has high transmittance for recording/reproducing light, such as acrylic resin, polyester resin, polycarbonate resin, or vinyl resin. , polysulfone resins, polyolefin resins, cellulose derivatives, etc.

The organic dye used in the optical recording layer has a reflectance near the wavelength of the light used, for example, when the wavelength of the energy beam of the reproduction light is 650 nm or more, especially 700 to 900 nm, the reflectance at the bit □ etc. which is the recording part It is preferable that the difference between the wavelength and the unrecorded area is large, and the wavelength to be recorded must have absorption in the above wavelength range. Further, it is preferable that the energy required to cause a change in reflectance by irradiation with an energy beam is small. Furthermore, it is preferable that the reflectance of recorded parts (pits, etc.) and unrecorded parts is not easily changed by the energy beam of reproduction light.

For example, anthraquinone derivatives (especially those having an indathrene skeleton), dioxazine compounds and their derivatives, triphuedithiazine compounds, phenanthrene derivatives, cyanine compounds, merocyanine compounds, biryllium compounds, xanthine compounds, triphenylmethane compounds, croconium pigments, azo pigments, crocones, azines, indigoids, polymethine pigments, azulenes,
Mention may be made of squalium conductors, sulfur dyes and dithiolate complexes of metals.

Further, these dyes may be mixed with a stabilizer. Examples of the stabilizer include various metal chelate compounds, particularly Zn, Cu, Nf, and Cr.

Polydentate ligands with Co, Mn, Pd, and Zr as central metals,
For example, N4 + N202, N2 S25402
In addition to those consisting of concave ligands such as S2, o, etc. or combinations thereof, various aromatic amines and diamines, nitrogen-containing aromatics and their onium salts, such as aminium salts, diimonium salts, and pyridinium salts. Examples include salts, iyodacilinium salts, quinolium salts, and the like. Furthermore, pyrylium salts, which are oxygen-containing aromatic salts, are also used. Moreover, a combination of two or more of these stabilizers can also be used.

The above-mentioned various stabilizers are selected in consideration of the compatibility between the above-mentioned organic dye and the solvent used. The amount of stabilizer added to the organic dye is preferably twt% to 50wt%, particularly 1
When the amount is 0 wt% to 30 wt%, there is little decrease in sensitivity and the effect as a stabilizer is high.

The solvent used to dissolve the above organic dyes and stabilizers is preferably a solvent that does not attack the resin sheet, such as diacetone alcohol, cellosolve, 1-methoxy-2-propanol, etc., and halogen-based It is also possible to use a mixed solvent in which a small amount of a solvent is added.

The sheet-like optical recording medium manufactured in this manner is then cut or punched into a shape corresponding to the concave-convex preformat signal of an optical disk, optical card, or the like.

Further, the pattern of the uneven preformat formed on the roller 3 of the present invention is specifically, for example, 11 meters and 0.5 μm.
~2μm, pitch 1.0μm~5μm spiral, concentric circle or parallel optical disk or optical card tracking group, width 2μm~5μm, pitch 8μm~15μm
It is a pattern of spiral, concentric circles, or parallel tracking groups for optical disks and optical cards.

In practice, it is possible to add labels, print lot numbers, store in a case, etc. during or after these steps. Additionally, feedback based on various inspection processes and inspection results is provided as necessary. For example, optical inspections include birefringence, media, coating film transmittance, reflectance, defect inspection for scratches and dust, sheet thickness,
Measurement to determine the quality of the molded grooves, evaluation of performance as a disk or card, etc. can be performed during or after the process.

(Example〕 Hereinafter, the present invention will be explained in more detail using Examples.

[Example 1] A polycarbonate pellet having an average molecular weight jL of 25,000 is used as a resin sheet material, and a resin sheet is molded at an extrusion width of 200 mm, a roll gap of 0.4 mm, and an extrusion speed of 3 m/min.

A coater 17 shown in FIG. 1 was used to coat the ultraviolet curing resin 21 to a thickness. Polyurethane acrylate was used as the ultraviolet curing resin. On the stambar roll 18, a stambar having tracks used for optical cards and grooves for preformatting is affixed. As for the uneven shape, linear guide grooves are formed as track grooves, and each convex portion formed as one groove with a pitch of 12 μm has a width of 2.5 μm and a height of 3000. The surface on which this pattern is formed is approximately 850mm x 300m
The overall size was 900 mm x 600 mm, covering a card shape of 850 mm x 540 mm.

A stand bar roller 18 having such a concavo-convex preformat pattern is pressed against the ultraviolet curing resin coated surface of the resin sheet 16, and a strength of 100 W/W is applied from the other surface of the resin sheet.
The uneven preformat was transferred and fixed onto the resin sheet by irradiating it with an AM ultraviolet lamp from a distance of 50 mm.

Next, a roll coater was used to coat the recording layer at 3 m/m.
The resin sheet was coated on the entire side of the resin sheet on which the uneven pattern was formed. The recording layer coating solution used was a polymethine dye (trade name IR-820 manufactured by Nippon Kayakuwa Co., Ltd.) dissolved in diacetone alcohol at a concentration of 2 wt %.

To dry the recording layer, dry air that had been salted at 30°C and passed through a 0.2 μm air filter was heated for 1 m from the opposite direction of the flow of the sheet to create a laminar flow in a 3 m long tunnel.
/min to 5 m/min and dried.

Next, as a protective member, a polycarbonate sheet with a thickness of 0.25 mm was overlaid with a resin sheet via a film-like hot melt adhesive, and a heated pressure roller 8 was used.
, 8', the total thickness of the lamination was 0.7 mm.

This was punched out using a press cutting machine to read a cutting marker provided in advance (formed at the same time as the uneven pattern was formed) to form an optical card.

Although this cutting can be done in a sufficiently short time, since the sheet is not fed continuously, a mechanism was provided to "sag" the sheet to enable this feeding between the formation of the protective member and the cutting.

(Effects of the Invention) As explained above, according to the method and apparatus for producing an optical recording medium of the present invention, from the formation of a resin sheet to the shape of a concavo-convex preformat, the formation of a recording layer, the formation of a protective member, and further cutting. Since the steps up to this point are carried out in a continuous process, there is less opportunity for dust to adhere to the optical recording medium, which can cause errors when recording and reproducing information, thereby making it possible to obtain a highly reliable optical recording medium.

In addition, since the process is continuous in the shortest possible time, the volume of the required clean room is reduced, making it extremely easy to create a clean tunnel on a continuous line, and further reducing the need for clean room facilities, making it possible to lower the price of optical recording media. .

Furthermore, in the present invention, since the step of applying the corrugated body is performed from the lower surface side of the resin sheet, it is possible to prevent dust from adhering to the resin sheet, thereby making it possible to obtain a highly reliable optical recording medium.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a continuous manufacturing method of a write-once optical recording medium according to the present invention. 1 is an extruder, 2.3.4 is a roller, 5 is a coater, 5' is an ink reservoir, 6 is a tunnel drying oven, 7 is a protective material feeder, 8.8' is a pressure roller, 9 is a protective material,
10 is a cutting machine, 11 is a hopper, 12 is a residual material, 13 is a drum, 14 is a conveyor belt, 15 is an optical recording medium, 16 is a resin sheet, 17 is a coater, 18 is a stamper roll, 1
9 is an ultraviolet light source, 20 is a conveyance roller, 21 is an ultraviolet curing resin, 2 is a slack mechanism, and 3 is a roller.

Claims (3)

[Claims] (1) A step of melting and extruding a resin to form a molten resin sheet, a step of applying a photocurable resin onto the resin sheet,
a step of pressing the resin sheet with a roller having a concave-convex preformat pattern and irradiating it with light to transfer the concave-convex preformat to the coating film of the photocurable resin; a surface on which the concave-convex preformat is formed on the resin sheet on which the concave-convex preformat is formed; A step of forming a recording layer on which information can be recorded and/or reproduced by light irradiation by coating, a step of forming a protective member on the formation surface of the recording layer, and a step of forming the resin sheet having the recording layer and the protective member into individual layers. 1. A method for manufacturing an optical recording medium, comprising a continuous step of cutting the recording medium. (2) From the step of melting and extruding the resin to form a molten resin sheet, to the step of applying a photocurable resin onto the resin sheet, to the step of transferring the uneven preformat to the coating film of the photocurable resin, and the step of transferring the concavo-convex preformat to the coating film of the photocurable resin. The step of forming a recording layer on the uneven preformat surface of the coating film, the step of forming a protective member on the recording layer, and the step of continuously forming and conveying the resin sheet, and cutting the resin sheet into individual recording media are The method for manufacturing a recording medium according to claim 1, wherein the resin sheet is conveyed intermittently. (3) means for melting and extruding resin to form a molten resin sheet; means for applying a photocurable resin onto the resin sheet;
A means for transferring the concavo-convex preformat to a coating film of photocurable resin on the resin sheet, and a recording layer capable of recording and/or reproducing information by irradiating light onto the concave-convex preformat formed surface of the resin sheet on which the concave-convex preformat is formed. , means for forming a protective member on the surface on which the recording layer is formed, and means for cutting the resin sheet having the recording layer and the protective member into individual recording media. Optical recording media manufacturing equipment. (4) The step of continuously conveying the resin sheet from extrusion of the resin sheet to before cutting the individual recording media, and cutting the resin sheet into individual recording media includes means for intermittently conveying the resin sheet. The optical recording medium manufacturing apparatus according to item (3).