JPH0442446A - Information recording medium and production thereof - Google Patents

Abstract

PURPOSE:To increase the strength of adhesion to forces in all directions and to reduce the thickness over the entire part as well as to increase sticking strength by mounting hubs having flange parts from the inner side of disk substrates in such a manner that the flange parts and the inside surfaces of the disk substrates form nearly the same plane. CONSTITUTION:This information recording medium 1 is constituted by sticking two sheets of the disk substrates 2 with recording layers 3 on the inner side to each other via an adhesive layer 7a. The insertion parts 6a of the hubs 6 respectively consisting of press moldings of a magnetic metallic plate are inserted from the recording layer 3 side into the inner central hole 5 on the inner peripheral part of the disk substrates 2. The hubs 6 are mounted by embedding the flange parts 6a into the recessed parts 2a of the disk substrates 2 in such a manner that the flange parts 6b form nearly the same plane as the inside surface of the disk substrates 2. The strength of adhesion to the forces in all the directions is increased in this way and the thickness over the entire part is reduced. In addition, the sticking strength is increased.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an information recording medium used as an optical disc, etc.
In particular, the present invention relates to an optical information recording medium that is fixed using a magnetic clamp method.

(Prior art) As a plastic information recording medium that writes and reads information by focusing light such as a laser beam on the recording medium layer, adhesive is used with the recording layer inside, either directly or through a spacer. Alternatively, they may be bonded together by ultrasonic welding, and one of the clamping methods for such information recording media is the magnetic clamping method.

FIG. 13 is a cross-sectional view showing the state of the conventional magnetic clamp type information recording medium shown in, for example, Japanese Unexamined Patent Publication No. 62-167663. In FIG. 1, 1 is an information recording medium made of transparent plastic. The two disk substrates 2 are pasted together through the inner spacer 4 and the outer spacer (not shown) so that the recording layer 3 is on the inside, and the hub 6 is inserted into the center hole 5 of the two disk substrates 2 from both sides. installed,
It is bonded by an adhesive layer 7. The hub 6 is the insertion part 6a
and a flange portion 6b, the insertion portion 6a is inserted into the center hole 5, and the flange portion 6b is bonded to the outside of the disk substrate 2 with an adhesive layer 7.

The information recording medium 1 is housed in a cartridge 8 and mounted on a turntable 9, so that information can be written and read thereon. A recess 10 is formed in the turntable 9, and a magnet 11 and a yoke 12 are provided, and these attract and fix the hub 6, and the spindle 13 is inserted into the center hole 14 of the hub 6 for positioning. , the information recording medium 1 is fixed.

The information recording medium 1 is mounted on the turntable 9 as described above and rotated, and the recording layer 3 is irradiated with a laser beam or the like from below through the disk substrate 2 to write and read information.

However, in such a conventional information recording medium, since the flange portion 6b of the hub 6 is located outside the disk substrate 2, if the diameter of the clamping area 15 formed in the recess 10 of the turntable 9 is small, , the diameter of the flange portion 6b also becomes smaller, which reduces the amount of adhesion.If the clamping area 15 is the same as or smaller than the center hole 5, adhesion is performed only on the end face of the insertion portion 6a, which reduces the adhesion strength. becomes smaller. The same applies when the clamping area 15 formed in the recess lO of the turntable 9 becomes shallow, and the recess 1 in the clamping area 15
If there is no 0 at all, that is, if the surfaces of the hub 6 and the disk substrate 2 match, they will be bonded only at the end surfaces.
Adhesive strength decreases.

Figure 14 shows Utility Model Application Publication No. 1-974 in order to improve the above-mentioned drawbacks.
71 is a cross-sectional view of the information recording medium proposed in No. 71. Here, the information recording medium 1 has two disk substrates 2 and a recording layer 3.
They are pasted together with adhesive 17a with the inner side facing inside. A hub spacer 1 is placed between the inner peripheries of the two disk substrates 2.
6 is interposed therebetween, and is bonded to the disk substrate 2 by an adhesive layer 7a.

The inner peripheral portion of the hub spacer 16 protrudes into the center hole 5 of the disk base plate 2, and has a center hole 14 at its center. 2
A metal hub 6 is inserted into the center hole 5 from the outer surface side of the disk substrate 2, and its tip end is adhered to the inner peripheral part of the hub spacer 16 by an adhesive layer 7. The hub 6 has a cylindrical shape as a whole, has no flange portion, and has an outer surface protruding from the outer surface of the disk substrate 2 to form a protruding portion 6c.

The above-mentioned information recording medium 1 is also used in the same manner as the one in FIG.

However, in all of the above information recording media 1, the flange portion 6b or the hub spacer 16 is mechanically engaged in the pushing direction of the hub 6, so the strength against the force in the pushing direction is large, but the strength in the pulling direction is large. It has low strength and is easily damaged.

Since the hubs 6 are attached after the disk substrates 2 are bonded together, if the attachment position of one of the hubs is shifted, the entire product will be defective, resulting in problems such as a low product yield.

[Problem to be solved by the invention]

The purpose of the present invention is to solve the above problems.

Even when the diameter and depth of the turntable's clamping area are reduced, it is possible to have a large adhesive margin between the hub and the disc substrate, and to increase the adhesive strength against forces in all directions.

Moreover, it is an object of the present invention to provide an information recording medium that can be made thinner overall and have increased bonding strength.

Another object of the present invention is to propose a method for manufacturing an information recording medium with high bonding strength easily and at a high yield by uniformly applying an adhesive to a disk substrate.

[Means to solve the problem]

The present invention is the following information recording medium and its manufacturing method.

(1) A recording layer is formed on one side of at least one transparent resin substrate, and the two are bonded together with the recording layer inside.
It has a disc board, an insertion part inserted into the center hole of the disc board, and a flange part that covers the disc board near the center hole from the inside, and two hubs that are attached to the center hole from the inside. An information recording medium, characterized in that the flange portion is embedded so as to form substantially the same surface as the inner surface of the disk substrate.

(2) The information recording medium according to (1) above, in which the disk substrate is bonded directly or via a spacer.

(3) The information recording medium according to (1) or (2) above, wherein the disk substrate and/or the hub are bonded together with an adhesive.

(4) Insert the hub having an insertion part and a flange part into the center hole from the recording layer side of the disk substrate, and embed the hub so that the flange part forms almost the same surface as the inner surface of the disk substrate. a step of applying adhesive to the recording layer side of the disk substrate and the flange of the hub;
A method for manufacturing an information recording medium, comprising the step of bonding a disk substrate and a hub coated with an adhesive to another disk substrate and a hub.

(5) The method described in (4) above, wherein the adhesive is applied using a roll coater.

(6) The method described in (5) above, wherein the disk substrate with the hub attached thereto is placed on a conveyor divided into two and moved, and the adhesive is applied by a roll coater.

(7) The method described in (5) above, wherein the disk substrate with the hub attached thereto is placed on a pedestal and moved, and the adhesive is applied using a roll coater.

(8) The method described in (4) above, wherein the adhesive is applied by a dispenser.

(9) The above (4) in which two sets of disk substrates and hubs are bonded together with adhesive either directly or via a spacer.
The method described in any one of to 8).

As the material for forming the disk substrate, transparent inorganic materials such as glass; transparent thermoplastic resins such as polycarbonate, polymethyl methacrylate, polyolefin, etc. can be used.

Preferred resins include (a) a copolymer of cyclic olefin and ethylene represented by the following general formula [1], which has an intrinsic viscosity [η] of 0.05 to 1 Odj2/g as measured in decalin at 135°C; or (b) an amorphous polyolefin consisting of a ring-opening polymer of a cyclic olefin represented by the following general formula [1] or a hydrogenated product thereof.

(In the formula, n is 0 or 1, m is O or a positive integer.

R1 to R10 each independently represent an atom or group selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group, and R554xa may be bonded to each other to form a monocyclic or polycyclic ring; RIS and R1'' or RIB and Hll may form a divalent hydrocarbon group. The monocyclic or polycyclic ring formed by Hlg, R11 has a double bond. In addition, as the recording layer formed on the disk substrate, for example, Te-C, Te-Cr, Te-Cr''C, Tb-Fe-
An optical memory material layer made of Co, Tb-Fe-co plus pt or Pd, and an underlayer, antireflection layer, and reflective layer laminated on and/or under these optical memory material layers as necessary. It can be composed of a layer, an interference layer, and a protective layer.

The hub may be made of a magnetic material at least at the tip end on the outer surface side. In the present invention, the term "magnetic material" refers to a magnetic material itself or a composite of a magnetic material and another material. Specifically, for example, materials made of ■magnetic metal, ■plastic blended with magnetic material, ■plastic with magnetic metal attached to the tip of the insertion tube, etc. can be used, but in terms of strength and attraction, ■or ■ preferable.

As an adhesive for bonding the disk board and hub.

Thermosetting adhesives such as amino resin, phenolic resin, resorcinol, xylene resin, furan resin, epoxy resin, polyisocyanate, unsaturated polyester, acrylic resin; vinyl acetate, acrylic, ethylene copolymer, polyamide, polyester , thermoplastic adhesives such as polyurethane; rubber adhesives such as polychloroprene type, nitrile rubber type, recycled rubber type, SBR type, natural rubber type; rubber type, acrylic type, emulsion type, oligomer type, hot melt type, Pressure-sensitive adhesives such as thermosetting and moisture-curing types; hot-melt adhesives such as water-soluble, high-temperature, reactive, and pressure-sensitive adhesives; instant adhesives such as cyanoacrylate adhesives; anaerobic adhesives, etc. Sonic or high-frequency welding may be used, and acrylate or epoxy UV-curable adhesives are preferred.

The above adhesives can also be used to bond disk substrates or hubs together, but water-soluble and high-temperature type 1
Hot melt adhesives such as reactive type and pressure sensitive type are preferred.

[For production]

In the information recording medium of the present invention, the insertion part of the hub is inserted into the center hole from the recording layer side of a disc substrate having a recess corresponding to the flange part of the hub, and the flange part forms almost the same surface as the inner surface of the disc substrate. As shown, the flange portion is embedded in the recess of the disk substrate and the hub is attached, and in this state, adhesive is applied to the recording layer side of the disk substrate and the flange portion of the hub.

This is manufactured by bonding this with other disk substrates and hubs.

The information recording medium manufactured in this way is mounted by attracting the tip of the outer surface of the hub to the magnet of the turntable and clamping it. and rotate the turntable,
Information is written and read by irradiating the recording layer with laser light or the like from below through the disk substrate.

The above information recording medium can be used even if the diameter and depth of the clamping area of the turntable are small.

Correspondingly, the dimensions of the outer surface of the hub can be changed, and even in that case, it is possible to enlarge the insertion portion and flange portion of the hub to increase the bonding margin and increase the bonding strength. In addition, since the flange of the hub is flush with the inner surface of the disk substrate, the overall thickness is thinner, and in this case, the adhesive can be applied evenly, increasing the bonding strength of the disk substrate. .

In addition, the flange of the hub engages with the disk substrate from the inside, so it has great strength against the force in the pulling direction.Also, since the flanges are fixed facing each other, it has great strength against the force in the pushing direction, so it can handle all kinds of problems. High adhesive strength against directional forces.

The above information recording medium is manufactured by attaching the hub to the disk substrate and then bonding two sets of disk substrates and the hub. Therefore, the shift in the mounting position of the hub is detected at the stage when the hub is attached to the disk substrate. , product yield is improved by gluing only correctly attached items.

〔Example〕

Hereinafter, the present invention will be explained with reference to embodiments of the drawings.

1 to 6 are cross-sectional views showing information recording media according to different embodiments.

In FIG. 1, an information recording medium 1 has two disk substrates 2 bonded together with the recording layer 3 inside with an adhesive layer 7a interposed therebetween. An insertion portion 6a of a hub 6 made of a press-molded magnetic metal plate is inserted into the center hole 5 from the recording layer 3 side of the disk substrate 2 at the inner peripheral portion of the two disk substrates 2.
The hub 6 is inserted into the recess 2a of the disk substrate 2 so that the flange portion 6b covers the vicinity of the center hole 5 of the disk substrate 2 from the inside. hub 6
The flange portions 6b of are bonded to each other by an adhesive layer 7a,
The insertion portion 6a and flange portion 6b of the hub 6 and the disk substrate 2 are fixed to each other by an adhesive layer 7b.

FIG. 2 shows an example of an air sand inch type information recording medium 1, in which the outer periphery of a disk substrate 2 is adhered with an adhesive layer 7a via an outer periphery spacer 18, and a gap 19 is formed between the disk substrates 2. There is. The hub 6 has a concave portion 6d formed in a portion of the flange portion 6b on the insertion portion 6a side, and a large amount of adhesive layer 7b.
to increase adhesion. The flanges 6b are bonded together by an adhesive layer 7c that is the same as the adhesive layer 7a. The other configurations are the same as in FIG. 1.

Figure 3 is also an example of the air sandwich type.

The hub 6 is made of plastic, and a magnetic metal plate 20 is bonded to the tip on the outer surface side. In addition, the inner circumferential portion of the disk substrate 2 and the flange portion 6b of the hub 6 are provided with an inner circumferential spacer 4.
They are bonded together via an adhesive layer 7b. hub 6
may be made entirely of magnetic metal; the other configurations are the same as in FIG.

FIGS. 4 to 6 show examples of a full-surface contact type information recording medium 1 similar to that shown in FIG. 1. In these embodiments, the hub 6 is made of magnetic metal, and in FIG.
A protruding portion 6c protrudes from the entire portion a, and in FIG.
In FIG. 6, a protrusion 6c protrudes from the center of the insertion portion 6a. The hub 6 is made of plastic,
A magnetic metal plate may be bonded to the tip on the outer surface side, and the other configurations are the same as in FIG. 1.

Next, a method for manufacturing the information recording medium 1 will be explained.

1 and 4 to 6, a hub 6 is inserted into a center hole 5 from the recording layer 3 side of a disk substrate 2 having a recess 2a corresponding to a flange 6b. 6a, embed the flange portion 6b in the recess 2a of the disk substrate 2 so that the flange portion 6b forms almost the same surface as the inner surface of the disk substrate 2, and fix the hub 6 with an adhesive layer 7b. In this state, disk board 2
An adhesive WI7a is applied to the side of the recording layer 3 and the back side of the flange portion 6b of the hub 6, and this is bonded to another disk substrate 2 and the hub 6, thereby producing the disc. In the case of the air sand inch type shown in FIGS. 2 and 3, an outer periphery spacer 18 is interposed between the outer peripheries of the disk substrate 2, and in the case of FIG. 3, an inner periphery spacer 4 is further interposed between the flange parts 6b. ,
It is manufactured by bonding the outer peripheral portion with an adhesive layer 7a and bonding the flange portions 6b with an adhesive layer 7c.

FIG. 7 is a cross-sectional view showing the adhesive application process using a roll coater, FIG. 8 is a perspective view thereof, FIG. 9 is a cross-sectional view showing the adhesive application process using a roll coater in another embodiment, and FIG. The figure is an enlarged view of a part thereof, FIG. 11 is a perspective view showing the adhesive application process using a dispenser, and FIG. 12 is a sectional view showing the bonding process.

When manufacturing the fully contact type information recording medium 1 shown in FIGS. 1 and 4 to 6, in the examples shown in FIGS. 7 and 8, the disk substrate 2 on which the hub 6 is attached is divided into two parts. The hub 6 accommodated in the gap between the conveyors 21 is introduced into the roll coater 22 in the direction of the arrow by the conveyor 21 . In the roll coater 22, the disk substrate 2 passes between a coating roll 23 and a pressure roll 24 which is divided into two parts, while a hot melt adhesive 26 is heated and melted in a tank 25.
is supplied to the coating roll 23, adjusted to a constant thickness by the thickness adjustment plate 27, and applied to the disk substrate 2 and the flange portion 6b of the hub 6 to form the adhesive layer 7a. The disk substrate 2 on which the adhesive M7a has been formed is moved to the next process by the conveyor 28. In the example shown in FIGS. 9 and 10, the disk substrate 2 with the hub 6 mounted thereon is placed on a pedestal 29, transported by a conveyor 21.28, and is coated with true melt adhesive 26 by a roll coater 22. In this case, the hub 6 is housed in the pedestal 29, so the conveyor 21
．． 28 and the pressure roll 24 do not need to be divided into two,
The hot melt adhesive 26 can be applied uniformly.

When manufacturing the air sand inch type information recording medium 1 shown in FIGS. 2 and 3, as shown in FIG. Adhesive layers 7a and 7c are formed on the flange portion 6b of the hub 6 and the flange portion 6b of the hub 6.

The two sets of disk substrates 2 on which the hub 6 is attached and on which the adhesive layers 7a and 7c are formed are stacked with the adhesive layers 7a and 7c facing each other, as shown in 121!1.
It is placed on the fixed mold 32 of the room temperature press device i31, and is pressed and bonded by moving the movable mold 33 in the direction B. In the case of the air sandwich type shown in FIG. 2, they are bonded together with an outer circumferential spacer 18 interposed therebetween.

In the case of FIG. 3, they are bonded together with an inner spacer 4 interposed therebetween. The disk substrate 2 is cooled to a temperature below the melting temperature of the adhesive 26 to harden the adhesive layers 7a and 7c.
The hub 6 is then bonded, and the information recording medium 1 is manufactured.

The information recording medium 1 manufactured in this manner is attached by attracting the tip of the outer surface of the hub 6 to the magnet 11 of the turntable 9 and clamping it, as shown in FIG. Then, the turntable 9 is rotated, and the recording layer 3 is irradiated with a laser beam or the like from below through the disk substrate 2, thereby writing and reading information.

In the information recording medium 1 described above, even if the diameter and depth of the clamping area 15 of the turntable 9 are small, the dimensions of the outer surface side of the protrusion 6c of the hub 6 can be changed accordingly. However, it is possible to increase the size of the insertion portion 6a and flange portion 6b of the hub 6 to increase the bonding margin and increase the bonding strength. Further, since the flange portion 6b of the hub 6 forms the same surface as the inner surface of the disk substrate 2, the thickness of the information recording medium 1 as a whole becomes thinner. In this case, since the adhesive can be applied uniformly, the bonding strength of the disk substrates 2 is increased.

In addition, the hub 6 has a flange portion 6b that is connected to the disk substrate 2 from the inside.
Since the flange portions 6b are engaged with each other, the strength against the force in the pulling direction is high, and since the flanges 6b face each other and are fixed, the strength against the force in the pushing direction is also high, and the adhesive strength against the force in all directions is high.

In the above manufacturing method, the information recording medium 1 is a disk substrate 2
Since the hub 6 is mounted on the disk board 2 and then two sets of the disk board 2 and the hub 6 are mounted on the hub 6, a shift in the mounting position of the hub 6 is detected at the stage where the hub 6 is mounted on the disc board 2.
Product yield is improved by joining only correctly mounted items.

That is, in the information recording medium 1, the center of the group groove formed on the disk substrate 2 and the center of the hub 6 must be -e apart, and the ISO standard requires that the amount of eccentricity be 5 μ- or less. Conventionally, the hub 6 was attached after the disk substrates 2 were pasted together, so if the eccentricity on one side was out of specification, the entire product would be defective, and the two pairs of disk substrates 2 and hubs 6 would be wasted. However, if the hub 6 is laminated after being installed as in the present invention, the amount of eccentricity can be detected at the stage when the hub 6 is installed, and the yield can be improved by laminating only those that meet the specifications at this stage. improves. In addition, non-standard items can be easily corrected, resulting in less waste.

In the above embodiment, different adhesives were used for the adhesive layers 7a and 7c and the adhesive layer 7b, but the same adhesive may be used. Furthermore, welding may be performed by ultrasonic or high-frequency welding without using an adhesive. Furthermore, the materials, structures, etc. of the disk substrate 2, hub 6, etc. are not limited to those of the above embodiments, and can be changed.

【Effect of the invention〕

As described above, in the information recording medium of the present invention, the hub having the flange portion is mounted from the inside of the disk substrate so that the flange portion and the inner surface of the disk substrate form almost the same surface, so that the turntable can be clamped easily.・Even if the diameter and depth of the area become smaller, the adhesive margin between the hub and the disk substrate can be increased, and the adhesive strength against force in all directions can be increased.
Furthermore, the overall thickness can be reduced and the bonding strength can be increased.

In addition, in the method for manufacturing an information recording medium of the present invention, after attaching the hub to the disk substrate, the adhesive is applied and bonded, so that the adhesive is evenly applied to the disk substrate and the bonding strength is high. information recording media easily and efficiently.
It can be manufactured with a high yield and waste of materials can be reduced.

[Brief explanation of the drawing]

1 to 6 are cross-sectional views showing information recording media according to different embodiments, FIG. 7 is a cross-sectional view showing the adhesive application process using a roll coater, FIG. 8 is a perspective view thereof, and FIG. The figure is a sectional view showing an adhesive application process using a roll coater in another embodiment. Fig. 10 is an enlarged view of a part of it, Fig. 11 is a perspective view showing the process of applying adhesive with a dispenser, Fig. 12 is a sectional view showing the bonding process, and Figs. 13 and 14 are conventional information. FIG. 2 is a cross-sectional view of a recording medium. In each figure, the same reference numerals indicate the same or corresponding parts. 1 is an information recording medium, 2 is a disk substrate, 3 is a recording layer, 4
is an inner spacer, 5 is a center hole, 6 is a hub, 6a is an insertion part, 6b is a flange part, 7.7a, 7b, 7c are adhesive layers, 18 is an outer spacer, 21.28 is a conveyor,
22 is a roll coater, 26 is a hot melt adhesive, 29
3 is a pedestal, 30 is a dispenser, and 31 is a room temperature press device.

Claims (9)

[Claims] (1) two disk substrates having a recording layer formed on one side of at least one transparent resin substrate and bonded together with the recording layer inside, and an insertion portion inserted into the center hole of the disk substrate; and a flange portion that covers the disk substrate near the center hole from the inside, and two hubs that are attached to the center hole from the inside, and the flange portion is arranged to form almost the same surface as the inner surface of the disk substrate. An information recording medium characterized by being embedded in. (2) The information recording medium according to claim (1), wherein the disk substrate is bonded directly or via a spacer. (3) The information recording medium according to claim (1) or (2), wherein the disk substrate and/or the hub are bonded together with an adhesive. (4) Insert the hub having an insertion part and a flange part into the center hole from the recording layer side of the disk substrate, and embed the hub so that the flange part forms almost the same surface as the inner surface of the disk substrate. a step of applying adhesive to the recording layer side of the disk substrate and the flange of the hub;
A method for manufacturing an information recording medium, comprising the step of bonding a disk substrate and a hub coated with an adhesive to another disk substrate and a hub. (5) The method according to claim (4), wherein the adhesive is applied using a roll coater. (6) The method according to claim (5), wherein the disk substrate with the hub attached is placed on a conveyor divided into two and moved, and the adhesive is applied by a roll coater. (7) The method according to claim (5), wherein the disk substrate with the hub mounted thereon is placed on a pedestal and moved, and the adhesive is applied by a roll coater. (8) The method according to claim (4), wherein the adhesive is applied by a dispenser. (9) Claim (4) in which two sets of disk substrates and hubs are bonded together with an adhesive directly or via a spacer.
) to (8).