JPH01307039A - Production of information recording medium - Google Patents

Abstract

PURPOSE:To prevent camber and distortion from generating in a disk substrate by welding ring-type spacers to the under surface of a resin substrate, stacking this substrate on another one and welding said spacers to the another substrate. CONSTITUTION:The ring-type outer and inner spacers 22 and 23 are placed on a supporting table 26, on which the disk-type resin substrate 21 is stacked with its recording layer down. Then ultrasonic horn 25 is brought to contact to weld and joint the substrate 21 and spacers 22 and 23. Another disk-type resin substrate 31 is placed on the supporting table 36 with the recording layer up, on which the former substrate 21 with spacers is stacked with the spacers down. The substrate 31 and spacers 22 and 23 are jointed with using the ultrasonic horn 35. By this method, the obtained disk has little distortion and excellent dimensional accuracy, so that the surface vibration and axial accelation of the medium during driving can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a method for manufacturing an information recording medium. More specifically, the present invention relates to a method of manufacturing an information recording medium in which disc-shaped resin substrates are overlapped and fused and bonded.

[Technical Background of the Invention] In recent years, information recording media using high energy density beams such as laser beams have been developed and put into practical use. This information recording medium is called an optical disk, and includes video disks, audio disks, large-capacity still image file storage, large-capacity computer disks, etc.
A vine used as memory.

The basic structure of an optical disk is a disc-shaped transparent resin substrate made of plastic or the like, and a recording layer provided thereon. The surface of the substrate on which the recording layer is provided is coated with an undercoat layer or an intermediate layer made of a polymeric material in order to improve the flatness of the substrate, improve the adhesion with the recording layer, and improve the sensitivity of the optical disc. Sometimes it is provided.

Various types of optical discs are known, but in recent years, air sandwich structures in which the substrate is bonded with the recording layer on the inside through inner and outer ring-shaped spacers have become common. ing. As a method for manufacturing an optical disk, a method has been proposed in which a resin substrate and inner and outer ring-shaped spacers are fused and bonded using an ultrasonic fusion bonder (for example, Japanese Patent Laid-Open No. 103537/1983). As seen in the above-mentioned publication, from the viewpoint of shortening the process, ultrasonic welding is usually performed in one step. However, in such a method, the spacer is likely to move due to ultrasonic vibrations and uneven bonding is likely to occur.
Publication No. 39 discloses the following as a detailed explanation. This will be explained with reference to FIGS. 2 and 4 of the accompanying drawings.

In FIG. 2, an inner ring-shaped spacer 22 and an outer ring-shaped spacer 23 are placed concentrically on a disk-shaped receiving jig 26, and a disk-shaped resin substrate 21 having a recording layer 27 is placed thereon for recording. Layer them so that the layers are on the inside.

Then, the ultrasonic application horn 25 of the ultrasonic fusion splicer is brought into contact with the surface of the resin substrate corresponding to each ring-shaped spacer, and ultrasonic energy is applied to fuse the resin substrate 21 and each ring-shaped spacer 22, 23. Wear and join.

After that, as shown in FIG. 4, the resin substrate 21 with spacers obtained in FIG. A disk-shaped resin substrate 41 having a recording layer 47 is stacked on top of the substrate so that the recording layer is on the inside.

Then, the ultrasonic application horn 45 of the ultrasonic fusion splicer is brought into contact with the surface of the resin substrate corresponding to each ring-shaped spacer, and ultrasonic energy is applied to fuse the resin substrate 41 and each ring-shaped spacer 22, 23. Wear and join. In this way,
An information recording medium consisting of two substrates is obtained.

However, although the optical disk manufactured by the above method has been improved from the drawback that the spacer easily moves and the bonding unevenness has been somewhat reduced, warpage and distortion may still occur, resulting in poor dimensional accuracy. For this reason, surface runout and axial acceleration during rotational driving may increase.

[Object of the Invention] An object of the present invention is to provide a method for manufacturing an information recording medium that can bond two resin substrates well.

[Summary of the Invention] The present inventor has set an inner non-recording area and an outer non-recording area on the outside of the periphery and inside the outer periphery of a hole, at least one of which is provided in the center. and 1
[Information formed by joining two disc-shaped resin substrates, which are disc-shaped resin substrates with a recording layer formed between the non-recording areas, through an inner ring-shaped spacer and an outer ring-shaped spacer. In a method for manufacturing a recording medium, an inner ring-shaped spacer and an outer ring-shaped spacer are arranged concentrically on a disk-shaped receiving jig, the resin substrate is arranged concentrically thereon, and an ultrasonic applying horn is placed on the resin substrate. in contact with the surface of the resin substrate corresponding to each ring-shaped spacer,
A first step of applying ultrasonic energy to fuse and bond the resin substrate and each ring-shaped spacer, and placing another resin substrate of the same type as the above-mentioned resin substrate concentrically on a disk-shaped receiving jig. Then, the resin substrate bonded with the spacers obtained in the first step is placed concentrically on the other resin substrate with the spacer side facing down, and the ultrasonic application horn is placed at the end corresponding to each ring-shaped spacer. A method of manufacturing an information recording medium includes a second step of fusion-bonding the resin substrate and each ring-shaped spacer by contacting the surface of the resin substrate and applying MI Ff wave energy.

Preferred embodiments of the method for manufacturing an information recording medium of the present invention are as follows.

(1) The disk-shaped receiving jig used in the first step is
The method for manufacturing an information recording medium as described above, characterized in that a groove is formed at a position corresponding to the protrusion of each ring-shaped spacer.

[Detailed Description of the Invention] Embodiments of a typical manufacturing method of the present invention are shown in FIGS.
This will be explained in detail with reference to FIG.

FIG. 1 shows a numerical air sandwich type information recording medium, which is an example of an information recording medium according to the method of manufacturing an information recording medium of the present invention.

The method for manufacturing an information recording medium of the present invention is a method for manufacturing an information recording medium that can bond two resin substrates well, the first step being ultrasonic welding of one substrate and a spacer. Next, the spacer is ultrasonically fused to the other substrate (second step). It is characterized by being placed on the side of the ingredients.

In FIG. 2, an inner ring-shaped spacer 22 and an outer ring-shaped spacer 23 are attached to a disk-shaped receiving jig 26.
Disc-shaped resin substrates 21 arranged concentrically in L and having a recording layer 27 thereon are stacked so that the recording layer is on the inside.

The disk-shaped resin substrate 21 has a hole 29 provided in the center.
An inner non-recording area 14 and an outer non-recording area 15 are set outside the peripheral edge and inside the outer peripheral edge, respectively, and a recording layer 27 is formed between the non-recording areas. .

Here, in order to fix the spacer, it is preferable that the receiving jig is formed with a groove into which the protrusion of the spacer can be inserted. The ring-shaped protrusions of the inner ring-shaped spacer are 28a, 28b, and the ring-shaped protrusions of the outer ring-shaped spacer are 30a, 30b.

The resin substrate 21 corresponds to each ring-shaped spacer so that the ultrasonic application horn 25 of the ultrasonic fusion splicer can apply ultrasonic energy to the resin substrate and each ring-shaped spacer.
is placed on the surface of

In FIG. 3, a disk-shaped resin substrate 31 is placed concentrically on a disk-shaped receiving jig 36 with the substrate side facing down so that the recording layer is on top, and the disk-shaped resin substrate 31 is placed concentrically on top of the disk-shaped receiving jig 36. The spacer-equipped resin substrate 21 is placed on the resin substrate 31 with the recording layer side (spacer side) facing down. The ultrasonic application horn 35 of the ultrasonic fusion splicer is arranged on the surface of the resin substrate corresponding to each ring-shaped spacer so as to apply ultrasonic energy to the resin substrate 2 and each ring-shaped spacer, as shown in FIG. ing.

As shown in FIG. 2, the manufacturing procedure is to place an inner ring-shaped spacer 22 and an outer ring-shaped spacer 23 concentrically on F of a disk-shaped receiving jig 26, and then place a recording layer 27 thereon.
The disc-shaped resin substrates 21 having the same structure are stacked on top of each other so that the recording layer is on the inside.

Then, the ultrasonic application horn 25 of the ultrasonic fusion machine is brought into contact with the surface of the resin substrate corresponding to each ring-shaped spacer, and ultrasonic energy is applied to the resin plate 21 and each ring-shaped spacer 22, 23. and fusion bonded. This is the first step.

Thereafter, as shown in FIG. 3, the disk-shaped resin substrate 31 is
Place the substrate concentrically on the disc-shaped receiving jig 36 with the recording layer facing up, and place the resin plate with spacers obtained in step 11 on top of it. 21 on the recording layer side (
Place it on the resin substrate 31 with the spacer side facing down.

Then, the ultrasonic application horn 35 of the Mff wave fusion machine is brought into contact with the surface of the resin substrate 21 corresponding to each ring-shaped spacer, and ultrasonic energy is applied to bond the resin substrate 31 and each ring-shaped spacer 22, 23. Fusion bonding (this is the second step). In this way, an information recording medium consisting of two substrates can be obtained.

The information recording medium produced in this way (12) is a disk with small distortion and good dimensional accuracy, and therefore has small surface run-out during rotational driving and small axial acceleration. Therefore, it can be said that the information recording medium has excellent recording and reproducing characteristics.

The reason why the above effects can be obtained is considered as follows.

In the first step, the spacer is placed on the receiving jig side, and ultrasonic vibration is applied from the Mi sound wave application horn of the ultrasonic fusion machine from the resin substrate side to fuse the spacer. Since the ultrasonic vibration generates heat at the contact surface of the resin material, it is thought that heat is generated at the contact surface between the substrate and the spacer, resulting in fusion.

In the next second step, the other resin substrate is placed on the receiving jig side, and the ultrasonic wave application horn of the Mi sonic fusion machine is applied again from the substrate side of the resin substrate with spacers obtained in the first step. Apply sonic vibration to fuse. That is, heat is generated at the contact surface between the spacer of the resin substrate with the spacer and the other substrate, and the resin substrate is fused.

That is, not only in the first step but also in the second step, ultrasonic vibrations are applied from the same substrate side to which ultrasonic vibrations were applied in the first step. In other words, both the first and second culms are always Mt.
Since the ultrasonic vibration is applied while maintaining a certain distance from the f-wave application horn to the fusion M im , it is thought that the ultrasonic energy spreads uniformly over the fused portion. This makes it possible to fusion-bond the two substrates through the spacer without distortion.

Note that, although the example of the method for manufacturing an information recording medium explained in FIGS. 2 and 3 is in accordance with the present invention, it is not limited to the above example.

For example, the shape of the spacer, the shape of the ultrasonic horn, the shape of the receiving jig, etc. are not particularly limited.

As for the substrate, spacer, and recording layer constituting the information recording medium of the present invention, any publicly known substrates, spacers, and recording layers other than those that are characteristic of the present invention can be used, and these will be briefly explained below. do.

The resin substrate can be arbitrarily selected from various resin materials conventionally used as substrates for information recording media. Examples of substrate materials include cell-cast polymethyl methacrylate, injection-molded polymethyl methacrylate, and polymethyl acrylate in terms of substrate optical properties, flatness, processability, handling, stability over time, and manufacturing costs. Preferred examples include acrylic resin: vinyl chloride resin such as polyvinyl chloride and vinyl chloride copolymer; epoxy resin: amorphous polyolefin resin; and synthetic resin such as polycarbonate. Among these, preferred are polymethyl methacrylate, polycarbonate, and epoxy resin in terms of dimensional stability, transparency, and flatness. It is particularly preferable to do so.

Each ring-shaped spacer used in the present invention includes:
Use one made of thermoplastic resin. By ultrasonic fusion method,
There is no particular limitation on the material as long as it can be well fused to the resin substrate. For purposes of the present invention, it is particularly preferred to use a material similar to the resin substrate material.

The surface of the substrate on which the recording layer is provided has improved flatness,
In order to improve adhesive strength and prevent deterioration of the recording layer, an undercoat layer (and/or intermediate layer) may be provided.

Examples of materials for the coating layer (and/or intermediate layer) include polymethyl methacrylate, acrylic acid/methacrylic acid copolymer, nitrocellulose, polyethylene,
Polymers such as chlorinated polyolefins, polypropylene, and polycarbonates; organic substances such as silane coupling agents; and inorganic oxides (Si02, A2,03
etc.), and inorganic substances such as inorganic fluoride (MgFz).

Examples of materials used for the recording layer include Te, Zn, I
n, Sn, Zr, A1, Ti, Cu, Ge, Au, Pt
Metals such as Bi, As%Sb, etc.; Semiconductors such as Si; and alloys thereof, or combinations thereof.

Compounds such as sulfides, oxides, borides, silicon compounds, carbides, and nitrides of these metals, semimetals, or semiconductors; and mixtures of these compounds and metals can also be used in the recording layer. Alternatively, combinations of dyes, dyes and polymers, and dyes and the aforementioned metals and metalloids can also be used.

The recording layer may further contain various known metals, semimetals, or compounds thereof as recording layer materials.

The recording layer can be formed on the substrate directly or via an undercoat layer using the above-mentioned materials by methods such as vapor deposition, sputtering, ion blasting, and coating. The recording layer may be a single layer or a multilayer, but its layer thickness is generally 100 to 5500X in terms of optical density required for optical information recording.
It is preferably in the range of 150 to 1000.

Note that the surface of the substrate opposite to the side on which the recording layer is provided is coated with inorganic substances such as silicon dioxide, tin oxide, and magnesium fluoride to improve scratch resistance and moisture resistance.
A thin film made of a polymeric substance such as a thermoplastic resin or a photocurable resin may be provided by a method such as vacuum deposition, sputtering, or coating. Furthermore, the recording layer may be provided in a fused portion other than the recording area.

[Effects of the Invention] The information recording medium manufactured according to the present invention has a ring-shaped structure because two resin substrates are welded together through inner and outer spacers with low distortion and good accuracy using the τr method. Separation between the spacer and the resin substrate does not substantially occur, and the recording characteristics of the recording layer become stable over a long period of time.

Furthermore, since the distortion of the disk is small, the vibration during rotational driving and the acceleration in the axial direction are also small, and therefore it can be said that it is an information recording medium with excellent recording and reproducing characteristics.

Next, Examples and Comparative Examples of the present invention will be described.

However, each of these aspects does not limit the invention.

[Example 1] Disc-shaped polycarbonate substrate with pregrooves provided by injection molding [outer diameter: 130 mm, center hole inner diameter: 15 m]
m, thickness: 1.2 mm, pre-groove depth 2,800 angstroms, track pitch: 1.6 μm], a chlorinated polyolefin-containing coating solution [10 parts by weight of methyl ethyl ketone and 100 parts by weight of cyclohexanone with chlorine] 3 parts of polyethylene dissolved in 2 parts]
was applied to the outer periphery of the substrate using a spin coater, and then dried to form seven intermediate coating layers having a layer thickness of 500 angstroms. In:GeS:A in L of the above intermediate coating layer
A recording layer having a thickness of 300 angstroms was formed by codeposition at a ratio of u=66:22:12 (heavy ratio). In this way, a disk substrate consisting of a substrate and a recording layer was obtained.

The spacer was sandwiched between the two disks and joined by ultrasonic fusion as described below to obtain a sandwich type information recording medium. The manufacturing method will be explained with reference to the attached FIGS. 2 and 3.

As shown in FIG.
A disc-shaped resin substrate 21 is arranged concentrically on the recording layer and has a recording layer 27 thereon.

stacked so that it was on the inside.

Then, the ultrasonic application horn 25 of the ultrasonic fusion splicer is brought into contact with the surface of the resin substrate 21 corresponding to each ring-shaped spacer, and ultrasonic energy is applied to bond the resin substrate 21 and each ring-shaped spacer 22, 23. (first step to fusion bond)
.

Thereafter, as shown in FIG. 3, the disk-shaped resin substrate 31 is
Place the recording layer on top of the disc-shaped receiving jig 36 concentrically with the substrate side facing down, and place the
? The spacer-equipped resin substrate 21 was placed on the resin substrate 31 with the recording layer side (spacer) facing down.

Then, the ultrasonic application horn 35 of the ultrasonic fusion splicer is brought into contact with the surface of the resin substrate corresponding to each ring-shaped spacer, and ultrasonic energy is applied to bond the tree 1It1 substrate 31 and each ring-shaped spacer 22, 23. Fusion bonding (this is the second step). In this way, an information recording medium consisting of two substrates is obtained.

The ultrasonic welding was performed using Brannon Model 8800 as an ultrasonic welding machine, pressure: 20 psi,
The experiment was conducted under the condition that the oscillation time was 0.2 seconds.

[Comparative Example 1] An information recording medium was manufactured in the same manner as in Example 1 except that the second step was performed as follows. The manufacturing method will be explained with reference to FIG. 4 attached.

The resin substrate 21 with spacers obtained in the first step is placed concentrically on a disk-shaped receiver 46 with the substrate side facing down, and the disk-shaped resin substrate 41 has a recording layer 47 on the spacer. were placed one on top of the other so that the recording layer was on the inside.

Then, the ultrasonic application horn 45 of the ultrasonic fusion machine is brought into contact with the surface of the resin J^ plate corresponding to each ring-shaped spacer, and ultrasonic energy is applied to the resin substrate 41 and each ring-shaped spacer 22, 23. and were fused together.

The above ultrasonic welding was carried out using a Brannon Model 8800 as an ultrasonic welder, with a pressure crab of 20 psi,
The experiment was conducted under the condition that the oscillation time was 0.2 seconds.

[Optical disc evaluation] 1! The optical disc thus obtained was evaluated for axial surface deflection and axial acceleration using the method F below.

A total of 16 disks, 8 disks of the optical disk obtained in Example 1 and 8 disks of Comparative Example 1, were prepared.
The axial surface deflection was measured, and the measured values of each sample were subjected to statistical processing by fractional analysis to give an :f value.

A total of 16 discs, 8 discs of the optical discs obtained in Example 1 and 8 discs of Comparative Example 1, were prepared.
The axial acceleration was measured at rotational speeds of 180 Or, p, and m, and the measured values of each sample were statistically processed by fractional analysis and evaluated.

The jf value results of the amount of axial surface runout are shown in FIG.

Example 1 has an average value of 61 μm, and Comparative Example 1 has an average value of 1
06 μm, and both confidence limits are ±24.5 μm. This result was shown to be significant with a 5% significance level by fractional analysis. It can be seen that the information recording medium obtained by the manufacturing method of the present invention has an extremely small amount of axial runout.

The jf value results of the axial acceleration are shown in FIG.

Example 1 has an average value of 13.7 m/sec2, Comparative Example 1 has an average value of 21.6 m/sec2, and the confidence limit is ±3.4 m/sec2. This result was shown to be significant with a 1% significance level by fractional analysis.

It also shows that Comparative Example 1 does not satisfy the ISO standard. This shows that the information recording medium obtained by the manufacturing method of the present invention has extremely small axial acceleration.

Therefore, it is clear that the information recording medium obtained by the manufacturing method of the present invention has extremely little distortion.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a general air sandwich type information recording medium according to the method of manufacturing an information recording medium of the present invention. FIGS. 2 and 3 are diagrams for explaining an example of the method for manufacturing an information recording medium of the present invention. Figures 2 and 4 are +1 from the conventional figure? FIG. 2 is a diagram for explaining an example of a method for manufacturing an information recording medium. Figure 5 shows the axial surface run-out of Example 1 and Comparative Example 1.
This is a graph showing. FIG. 6 is a graph showing the axial surface acceleration of Example 1 and Comparative Example 1. 11a, flb, 21.31.4! Two disk-shaped resin substrates 12.22: Inner ring-shaped spacer 13.23: Outer ring-shaped spacer 14: Inner circumference non-recording area 15: Outer circumference non-recording area 24: Ultra-long wave fusion machine 25.35.45: Super Et wave application * -n 26.36
．． 46: Receiving jig 19a, 19b, 29.39.49: Hole 17a, 17
b, 27.37.47: recording layers 28a, 28b, 30a
, 30b: Ring-shaped convexity Patent applicant Fuji Koshin Film Co., Ltd. Agent Patent attorney Hata Yanagawa Figure 1 Figure 2 Figure 3/24 Figure 5 Figure 6! 1

Claims (1)

[Claims] 1. At least one of the holes has an inner non-recording area and an outer non-recording area set outside the periphery and inside the outer periphery, respectively; Information recording made by joining two disc-shaped resin substrates, which are disc-shaped resin substrates with a recording layer formed between the non-recording areas, via an inner ring-shaped spacer and an outer ring-shaped spacer. In a method for manufacturing a medium, an inner ring-shaped spacer and an outer ring-shaped spacer are placed concentrically on a disk-shaped receiving jig, the resin substrate is placed concentrically thereon, and an ultrasonic applying horn is placed. A first step of fusion-bonding the resin substrate and each ring-shaped spacer by contacting the surface of the resin substrate corresponding to each ring-shaped spacer and applying ultrasonic energy; A resin substrate is placed concentrically on a disk-shaped receiving jig, and the resin substrate to which the spacer obtained in the first step is bonded is placed concentrically on the other resin substrate with the spacer side facing down. and a second step of bringing an ultrasonic application horn into contact with the surface of the resin substrate corresponding to each ring-shaped spacer and applying ultrasonic energy to fusion-bond the resin substrate and each ring-shaped spacer. A method for manufacturing an information recording medium comprising: