JPS6276040A - Manufacture of optomagnetic recording medium - Google Patents

Abstract

PURPOSE:To preclude the possibility of deformation of a base due to humidity absorption or thermal expansion and exfoliation of a recording layer or the like by forming a recording layer made of a magnetic substance film having a magnetization easy axis in the vertical direction to the film face on an organic resin base formed with a guide groove and adhering a glass plate to both faces. CONSTITUTION:The 1st dielectric layer 13, a recording layer 14 made of a magnetic film having a magnetization easy axis on the film face in the vertical direction, the 2nd dielectric layer 15 and the light reflection layer 16 are formed continuously on the face formed with a guide groove 12 of the organic resin base 11 in, e.g., a multi-dimension sputtering device. Then glass plates 18a, 18b are adhered to both faces of the lamination body via adhesive layers 17a, 17b. Thus, the deformation of the medium such as deflection or the exfoliation of the recording layer from the base is avoided to obtain the optomagnetic recording medium with high reliability for a long period.

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention 1 relates to a method for manufacturing an optical recording medium, particularly right) A method for manufacturing a recording medium using a restored resin substrate and a medium using a glass substrate. The present invention relates to a method for manufacturing an optical F1 recording medium having the following characteristics.

[Technique of Invention + Ji's Back Circle and Its Problems] Magneto-optical recording media are attracting attention as recording media that have high density, large capacity, and are capable of recording, reproducing, and erasing. The magneto-optical recording medium is an Ia type II material with an axis of easy magnetization perpendicular to the film surface.
Q is used as a recording layer, and recording is performed in the form of E-1 conversion using thermal energy from a laser beam or the like, and reproduction is performed using a magneto-optical effect such as the Kerr effect. A recording layer formed in such a magneto-optical recording medium (1.t, TbCo, GdCo, 'rbFe, GdTb as A material)
Amorphous metal alloys such as Fe, TbDyF"e and the like are particularly promising.

On the other hand, optical substrates (such as substrate materials fl 1, acrylic, polycarbony, etc. in 6-layer recording media) and glass substrates, which are non-standard materials 11, are being inspected.

The substrate in an optical recording medium must have a guide groove to ensure that the servo, etc. Substrate (cast using a metal stamper with guide grooves formed).

The guide groove can be easily formed by injection molding or the like.

However, magneto-optical recording media in which a recording layer or the like is formed on an organic resin substrate are subject to large deformations such as warpage due to expansion due to moisture absorption of the substrate even in a normal atmosphere, which poses problems in terms of recording and reproducing characteristics. Furthermore, when exposed to high temperature and high humidity conditions (70°C, RH 90%) to examine long-term reliability (life), the recording layer etc. peeled off from the substrate due to large thermal expansion and hygroscopic expansion. There was a problem.

On the other hand, a glass substrate, which is an inorganic material, has a small coefficient of thermal expansion and does not have the problem of moisture absorption, but a major drawback is that it is very difficult to form guide grooves. Further, manufacturing the substrate by polishing increases the cost. That is, when using a glass substrate, at least one side is optically polished,
Apply one coat of resist and expose using a mask with guide grooves, or
Alternatively, an exposure device equipped with a precision feed mechanism and a laser beam generation source may be used to form a guide groove using resist.
Since the glass substrates must be etched using a reactive ion etching device (E) to form guide grooves one by one, it is extremely difficult to mass-produce the glass substrates.

[Purpose of the invention]

The present invention has been made in view of these conventional problems, and provides a method for producing a magneto-optical recording medium that is free from the risk of deformation due to moisture absorption or thermal expansion of the substrate or peeling of the recording layer, etc., and which is highly productive. The purpose is to provide

[Summary of the invention]

In order to achieve this object, the present invention first forms a recording layer made of a magnetic film having an axis of easy magnetization at least perpendicular to the film surface on an organic resin substrate on which guide grooves are formed, and then It is characterized by gluing a glass plate to.

In addition, the present invention secondly forms a photoreflector Di I on an organic resin substrate on which guide grooves are formed, then adheres a glass plate, and then peels off the organic resin substrate, and then forms at least a film on the photoreflector fMR. It is characterized by forming a recording layer made of a magnetic film having an axis of easy magnetization perpendicular to the plane.

〔Effect of the invention〕

According to the present invention, by sandwiching a recording layer etc. formed on an organic resin substrate on which guide grooves are formed between glass plates from both sides, the problem of moisture absorption and expansion caused by the organic resin substrate is eliminated. The overall coefficient of thermal expansion is dominated by that of the glass.

Therefore, a magneto-optical recording medium that is highly reliable over a long period of time can be obtained without causing deformation such as warping of the medium or peeling off of the recording layer from the substrate. Furthermore, since the guide grooves are formed on the organic resin substrate by casting, DA molding, etc., mass productivity is significantly improved compared to the case where the guide grooves are formed on a glass substrate. Further, since the glass plate bonded on both sides does not require polishing the entire guide surface unlike the glass substrate with guide grooves in conventional magneto-optical recording media, cost reduction can also be expected.

Furthermore, according to the present invention, a glass plate is adhered to an organic resin substrate on which guide grooves are formed via a light reflection layer, and after peeling off the organic resin substrate, a recording layer or the like is formed on the light reflection layer. Therefore, the substrate as a medium is a glass substrate, so
The problems encountered with conventional resin substrates are essentially solved. In addition, since the thermal expansion coefficient of glass is low, the expansion and contraction of the light reflection layer is restricted by the glass plate, and the actual thermal expansion coefficient of the light reflective layer is the same as that of glass, so the recording formed on it The thermal expansion coefficients of the layer and the dielectric 1 etc. are very close to each other, and a practically sufficient life characteristic can be obtained. In addition, while using a glass plate as the media substrate,
Since the guide grooves formed on the organic resin substrate can be transferred to the light reflective layer, the manufacturing process is greatly simplified compared to the case where a glass substrate with guide grooves is used, and the productivity is greatly improved.

As described above, according to the present invention, it is possible to significantly improve the long-term reliability and mass productivity of magneto-optical recording media.

(Embodiments of the Invention) A first embodiment of the method for manufacturing a magneto-optical recording medium according to the present invention will be described with reference to FIG. First, a paid resin substrate 11 having a guide groove 12 as shown in FIG. 1(a) is prepared. The material of this substrate 11 is, for example, acrylic, polycarbonate, etc., and the guide groove 12 is easily formed by ordinary casting, index molding, or the like. In addition, it is desirable that the substrate 11 has a high mechanical strength and a small resistance to the coefficient of thermal expansion of the glass plate to which it will be bonded later. is appropriate. However, if it is too thin, cleaning and handling will be inconvenient, so
．． Approximately 51M+ is desirable.

Next, as shown in FIG. 1(b), a first dielectric layer 13. A recording layer 14 made of a magnetic film having an axis of easy magnetization perpendicular to the film surface. The second dielectric layer 15 and the photoreflector fll=I tiles 16 are successively formed, for example, in a multi-source sputtering apparatus. Here, the first dielectric layer 13 acts as an interference layer to equivalently increase the Kerr rotation angle of the recording layer 14, and is made of, for example, BN, S i N, AgN, Ti
N.

A material with a thickness of about 1,000 layers such as SiO, Al 203, etc. is used.

As the recording layer 14, as described above, the material film is DbC.
o, GdCo, TbFe, GdTbFe.

Rare earth metals such as TbDyFe-i! ! A transferable amorphous alloy film is used. For example, taking the case of TbC0, T
The recording layer 14 can be formed by dual simultaneous sputtering using a b target and a Co target. Tb,! :C
The composition ratio of o can be varied depending on the input power of each target.

The thickness of the recording layer 14 was 500.

The second dielectric layer 15 is for protecting the recording layer 14, and may be the same as the first dielectric layer 13. The light reflecting layer 16 is normally provided in magneto-optical recording media, and is made of a material with high light reflectivity such as an aluminum film, and its lag J$ is about 1000 people.

1(C) on both sides of the laminate having the structure shown in FIG. 1(b).
), glass plates 18a and 18b are bonded via adhesive layers 178 and 17b, respectively. Contact W@17a,
17b is an organic adhesive, such as an ultraviolet curing resin (photo bond #100 manufactured by Sunrise Meisei, etc.)
is used. It is preferable that the glass plates 18a and 18b have a coefficient of thermal expansion close to that of the dielectric layer 13°15.
The temperature at which the magneto-optical recording medium is used is at most 50°C,
Also, considering that the temperature is around 70 to 80'C even under high temperature and high humidity tests, the coefficient of thermal expansion is 10 if it is a normal glass material.
Since it is below 0x10-' cm/°C, most types can be used. However, the glass plate 18b on the side where the laser beam is incident is preferably made of a glass material with a small birefringence index in order to prevent a decrease in C, . . . /N.

Here, optical polishing of the glass plates 18a and 18b is not required, and it is sufficient to simply process plate glass having a normal plate thickness of about 0.5 to 1 mm into a disk shape, so several dozen plates are coated with low melting point wax, etc. They can be bonded together to process the outer periphery and center hole, and can be manufactured at low cost.

Note that the light obtained in this way shown in FIG. 1(C) [
Information is recorded and reproduced on the a-air recording medium by irradiating it with a laser beam from the glass plate 18a side.

Next, a specific method for bonding the glasses 118a and 18b together as shown in FIG. 1(c) will be described using FIG. 2. As shown in FIG. 2, the vacuum chamber 21 is partitioned into two chambers A and B by a flexible partition wall 22 made of transparent silicone rubber or a thin Teflon sheet, and a glass plate is placed above the ultraviolet incident window 23b in chamber B. 18b is installed, and a predetermined amount of liquid ultraviolet curing resin 24b is dropped. Figure 1(b)
The hammer body 25 is supported by a deformable jig 26 made of Teflon or the like so that it can be positioned.

This laminate 25-F also contains a predetermined amount of liquid ultraviolet curing resin 2.
After dropping 4a, add another glass number 18a to jig 2.
Install it on the top of 6. Further, ultraviolet rays are also introduced from the ultraviolet and lined Q4 window 23a provided facing A-to. The jig 27 is a glass plate 18a.

18b and the center hole of the laminate 25, and is used for centering.

Using the 41 device as described above, the number of glasses is 18a by the following procedure.
, 18b are attached to the laminate 25.

(1) Both A and B of vacuum 1f121 are evacuated at the same time to completely defoam the liquid ultraviolet curing resin.

(2) Gradually return the Δ chamber to atmospheric pressure, and the glass plate 188°1
8b and the laminate 25 are pressurized via the partition wall 22 at atmospheric pressure.

(3) Leave this pressurized state for several minutes, and then remove the ultraviolet curing resins 24a, 24b (adhesive layer 17a in FIG. 1).

17b) is made sufficiently thin and uniform.

(4) Ultraviolet light input l1) Ultraviolet light is irradiated from one window 23a, 23b to cure the ultraviolet curing resins 24a, 24b.

(5) Take it out indoors and if necessary, irradiate it with ultraviolet light again to perform additional curing.

Through the above steps, each layer including the recording layer 14 is formed on the resin substrate 11, and a magneto-optical recording medium is obtained in which the whole is sandwiched between the glass plates 18a and 18b from both sides and firmly integrated. .

Next, a second embodiment of the method for manufacturing a magneto-optical recording medium according to the present invention will be described with reference to FIG. First, Figure 3 (a
) Prepare a resin substrate 31 having guide grooves 32 as shown in FIG. The material of this substrate 31 is, for example, acrylic, polycarbonate, etc., and the guide groove 32 is easily formed by ordinary casting, injection molding, or the like.

Next, as shown in FIG. 3(b), a light anti-tJI layer 34 is formed on the surface of the paid resin substrate 31 on which the guide groove 32 is formed, with a peeling layer 33 interposed therebetween. Peeling layer 33 and resin substrate 3
Metal oxides and metal nitrides that are useful when peeling 1 in the process described later, and have a coefficient of thermal expansion significantly different from that of the organic resin substrate 31.

It is made of a material such as a semiconductor oxide or a semiconductor nitride, and is formed to a thickness of about 50 to 500 layers using a sputtering method or the like. The light anti-sword knight 34 is made of a metal material with high light reflectance. In one example, a SiN film was formed to a thickness of 200 mm by sputtering as a peeling layer 1, and the photoreflection [J
As No. 34, an aluminum film was formed to a thickness of 1000 mm by the sputtering method.

Next, as shown in FIG. 3(C), a glass plate 36 is bonded onto the light reflecting layer 34 via an adhesive layer 35.

The adhesive layer 35 is an organic adhesive, for example, an ultraviolet curing resin (photo bond #10 manufactured by Sunrise Meisei Co., Ltd.).
0, etc.) are used. The glass plate 36 preferably has a thermal expansion coefficient close to that of the dielectric layer described later, but the temperature at which the optical recording medium is used is at most 50°C, and even under a high temperature and high humidity test, it is 70 to 80°C. Considering that the coefficient of thermal expansion is 100x for ordinary glass material,
Since it is less than 10-'cttr/'C, most can be used. Here, the glass plate 36 does not require optical polishing, and it is sufficient to simply process a plate glass with a normal plate thickness of about 0.5 to 1 mm into a disk shape, so several dozen pieces are pasted with low-melting wax or the like. In addition, the outer periphery and the center hole can be processed, and the product can be manufactured at a low cost.

Next, by utilizing the difference in thermal expansion coefficient between the stone layer resin substrate 31 and the peeling layer 33, the laminate shown in FIG.
℃P1. The stone layer resin substrate 31 is peeled by heating at a certain temperature, with the peeling llFm33 as a boundary. This process allows the third
As shown in Figure (d), a glass plate 36 on which a light reflecting element 34 has been formed via an adhesive layer 35 is taken out.

Next, as shown in FIG. 3(e), a first dielectric layer 37. A recording layer 38 and a second dielectric layer 39 made of a magnetic film having an axis of easy magnetization perpendicular to the film surface are successively formed, for example, in a multi-source sputtering apparatus. Here, the second dielectric layer 39 acts as an interference layer to equivalently increase the Kerr rotation angle of the recording layer 38, and is made of, for example, BN, SiN, AβN, T i N,
SIO.

A thin film such as Ag2'03 with a thickness of about 1000 mm is used.

As mentioned above, the magnetic film of the recording layer 38 is Tb.
Co, GdCo, DingbFe, GdTbFe.

Rare earth-1ff transfer metal amorphous alloy thin films such as TbDyFe are used. For example, taking the case of TbCo, T
The recording layer 38 can be formed by dual simultaneous sputtering using the b target and the c target. The composition ratio of Tb and CO can be controlled by the power of each target.

The thickness of the recording layer 38 was 500.

The first dielectric layer 37 is for protecting the recording layer 38 and improving the performance of the recording layer 38, and is the same as the three second dielectric layers. In the example, both the first and second dielectrics were formed to have a thickness of 6u and a thickness of 1000 mm.

The magneto-optical recording medium thus obtained shown in FIG. .

Next, a mounting method for bonding the light reflecting layer 34 and the glass plate 36 in the step of FIG. 3(C) will be explained using FIG. 4. As shown in FIG. 4, a vacuum chamber 41 is partitioned into two chambers A and B by a replaceable partition wall 42 made of transparent silicone rubber or a thin Teflon sheet.
A glass plate 36 is installed on the ultraviolet incident window 43, and a predetermined amount of liquid ultraviolet I! Drop the cured resin 44. Third
A jig 4 made of Teflon or the like that can deform the laminate 45 shown in Fig. 1
6 to support positioning.

Using such a device, you can make glass plate 36 at the next affordable price!
,! ! It is attached to the layered body 45.

(1) Vacuum chambers 41 A and B are simultaneously evacuated to completely suppress bubbles in the liquid ultraviolet curing resin.

(2) Chamber A is gradually brought to atmospheric pressure, and the glass plate 36 and the laminate 45 are pressurized to atmospheric pressure via the partition 42.

(3) This pressurized state is left for several minutes to make the ultraviolet curing resin 44 (adhesive layer 35 in FIG. 3) sufficiently thin and uniform.

(4) Ultraviolet rays are directed through the ultraviolet incident window 43 to cure the ultraviolet curable resin 44.

(5) Take it out into the room and peel off the Ij31 resin substrate 31 via the layer 33 using the difference in thermal expansion coefficient as described above.

As described above, according to this embodiment, the flat glass plate 36 without guide grooves is used as a substrate, and each layer including the light reflection layer 34 having guide grooves and the recording layer 38 is formed on the substrate. The magnetic recording medium is iq'd.

FIG. 5 shows an embodiment that is a modification of the embodiment shown in FIG.
After the process shown in FIG. A reliable, long-life magneto-optical recording medium can be obtained. In the medium shown in FIG. 5, the laser beam passes through the glass plate 52 during recording and reproduction, but the glass plate 52 is different from the recording layer 38 in the dielectric layer 3.
Since the glass plate 5 and the glass plate 51 are separated from each other, slight irregularities on the surface do not affect recording and reproduction.
Needless to say, the optical polishing in step 2 is bait.

[Brief explanation of drawings]

Fig. 1 is a process diagram for explaining a first embodiment of the method for manufacturing an optical R1 recording medium according to the present invention, and Fig. 2 is a cross-sectional view of the apparatus used in the same process. , FIG. 3 is a process diagram for explaining a second embodiment of the manufacturing method for a luminous social security certificate recording medium according to the present invention, and FIG. 4 is a cross-sectional view of the apparatus used in the same embodiment. No. bFF'w is a diagram showing the final process of an embodiment that is a modification of the embodiment of FIG. 3. 11.31... Organic resin substrate, 12.32... Guide groove, 13.15.37.39... Dielectric material, bitter, 14°38... Recording layer, 16.34... Light reflective layer, 178
゜17b, 35.51=...Adhesive layer, 18a, 18b. 36.52...Glass plate, 21.41...Vacuum layer,
22.42... Partition wall, 23a, 23b, 43-... Ultraviolet incident window, 24a, 24b, 44... Liquid ultraviolet curing resin, 25.45... Laminate, 26, 27. -46
...Jig. Applicant's agent Patent attorney Takeshi Suzuki et al.l1lIUv Figure 3 Figure 4 Figure 5

Claims (2)

[Claims] (1) A recording layer made of a magnetic film having an axis of easy magnetization at least perpendicular to the film surface is formed on an organic resin substrate on which guide grooves are formed, and then glass plates are bonded to both sides. A method for manufacturing a magneto-optical recording medium. (2) After forming a light-reflecting layer on the organic resin substrate on which guide grooves are formed, a glass plate is adhered, and then, after peeling off the organic resin substrate, the light-reflecting layer is placed on the light-reflecting layer at least in a direction perpendicular to the film surface. 1. A method for producing a magneto-optical recording medium, comprising forming a recording layer made of a magnetic film having an axis of easy magnetization.