JPS60138750A - Manufacture of information recording disc - Google Patents

Abstract

PURPOSE:To obtain an information recording disc with a short bonding time, high air-tightness and strong bonding force by providing a ring form rugged faucet to a bonding face between a spacer and the disc and bonding them with an ultrasonic welding method. CONSTITUTION:This film recording media 9, 9' are applied to the surface of transparent plastic discs 8, 8' and ring form pits 11, 11' are formed. Ring form dams 12, 12' are formed to both sides of the spacers 10, 10' and fitted to the ring form pits 11, 11'. The mated part is bonded by the ultrasonic wave melt- spraying method. Thus, the bonding time is short, the air-tightness is improved and the information recording disc with air-sandwich structure is obtained with strong bonding force.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an information recording substrate on which information is written and read by focusing light such as a laser beam, and particularly relates to a method of manufacturing an air sandwich type disk. .

A disk-shaped information recording substrate generally used for optical video disks, optical memories, etc. usually has a structure as shown in FIG. That is, thin film recording media 2 and 2' are provided on the surfaces of transparent plastic substrates 1 and 1' that transmit optical signals, and the two substrates 1 and 1 are arranged so that the recording media 2 and 2' face each other. ’ Place spacers 3 and 3 of plastic etc. on the inner and outer peripheries.
', and an intermediate nitrogen layer 4 is formed between the recording layers 2 and 2'.

Conventionally, the methods for manufacturing information recording substrates with an air sandwich structure using spacers include room-temperature curing type,
A common method is to bond them together using a thermosetting adhesive, a UV curing adhesive, or the like.

However, using adhesives requires a large amount of man-hours to apply to the substrate and spacer and cure the bond, and the heat required during curing and the gas generated during curing make it difficult to attach adhesives to disk substrates or substrates. There was a problem in that it caused deterioration of the recorded recording medium.

Furthermore, there are many defects in appearance due to unbalance of the substrate due to uneven adhesion and heating of the adhesive.

In order to eliminate such drawbacks, it is possible to manufacture an information recording substrate with an air-tended switch structure by the ultrasonic bath N method as shown in FIG.

That is, as shown in FIG.
After the spacers 3 and 3' having triangular annular protrusions 6 and 6' are sandwiched and fixed between them, a horn 7 of an ultrasonic welding machine (not shown) is pressed and pressurized from above. When ultrasonic waves are oscillated in this state, frictional heat concentrates on the protrusions 6 and 6' formed on the spacers 3 and 3', causing them to melt, thereby causing the substrates 1 and 1' and the spacers 3 and 3'
An information recording substrate having the same structure as that shown in FIG. 1 can be obtained.

However, according to the ultrasonic welding method shown in this figure, no means is taken to restrict the bonding layer due to melting of the protrusions, and when pressure is applied, it flows out beyond the bonding surface, resulting in a material that is loose. 1) There are numerous pinholes in the bonding layer, which has the disadvantage that complete airtightness cannot be obtained. If there is a pinhole in the bonding layer, air or dust may enter the inner layer 4 of the information recording substrate from the outside and cause condensation, absorption or scattering of transmitted light during reading and writing, or scratches or chemical damage to the recording medium. This often results in a reaction and a reduction in performance.

An object of the present invention is to eliminate such defects by providing an annular uneven fitting part on the joint surfaces of the spacer and the substrate, and by performing the joining by ultrasonic welding, the joining time is short and the airtightness is extremely high. The present invention provides a method for manufacturing an information recording substrate that has high bonding strength and strong bonding strength.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a sectional view showing an embodiment of the method for manufacturing an information recording substrate using the ultrasonic welding method of the present invention. ' is applied. Spacers 10 and 10' are sandwiched between the substrates 8 and 8', and rectangular annular grooves 11 and 11' are provided at the center of the bonding surfaces of the substrates 8 and 8', respectively. ′
Rectangular annular plates 12 and 12' are formed by injection molding on both sides of the annular grooves 11 and 11'.
and 12' are matched in a loose fit.

4 and 5 are partial sectional views showing in detail an example of the structure of the joint surface portion in FIG. 3. FIG.

This makes it possible to make the fitting structure shown in FIG. 3 more effective.

FIG. 4 shows that a triangular annular protrusion 15 is formed into a G shape by injection molding at the center of an annular plate 14 provided on both sides of a spacer 13, and at the center of an annular groove 17 provided on substrates 16 and 16'. in contact with the bottom. In addition, protrusion 1
Other examples of the shape 5 may be a semicircular shape or a minute convex shape.

FIG. 5 shows an annular groove 19 provided in the substrates 18 and 18'.
Both corner portions of the groove bottom are formed into slope-shaped portions 20,
It is in contact with annular plates 22 provided on both sides of the spacer 21.

When manufacturing an information recording substrate using a substrate and spacer having the above structure, the spacer 13 and the inner periphery are placed between the substrates 16 and 16' or 18 and 18' in the same way as the method shown in FIG. The base 5 is sandwiched between the spacer 21 (not shown) and the inner spacer (not shown).
After it is fixed to the surface, the horn of an ultrasonic welding machine (not shown) is pressed from above to emit ultrasonic waves. At this time, frictional heat concentrates on the annular projection 15 as shown in FIG. 4 and the sloped portion 20 of the annular groove 19 shown in FIG.
By melting the corresponding portions, the substrates 16 and 16' are joined to the spacer 13 and the inner spacer (not shown). As a result, the structure of the disk is exactly the same as that shown in FIG. 1, except that the structure of the joint portion is different as described above.

Furthermore, by providing an uneven fitting part on the bonding surface as in this example, the melted bonding layer accumulates in the groove and does not overflow to the outside, making it possible to suppress the bonding layer. In other words, by obtaining an airtight state, complete airtightness without leakage can be achieved. At this time, the thickness and joint area of the welded joint can be freely adjusted by adjusting the fit of the unevenness formed on the joint surface, the size of the protrusion 15 and the sloped part 20, and the ultrasonic amplitude of the horn 7 and the increase or decrease of the pressing force. Since it can be controlled, it is possible to obtain both a bonding layer of uniform thickness with no uneven adhesion and complete airtightness.

Incidentally, as shown in FIG. 6, the convex-concave fitting portion of the substrate and the spacer as explained above has annular plates 24 and 24' and spacers 25 and 2 on the bonding surface of the substrates 23 and 23'.
The annular grooves 26 and 26' may be provided on both sides of the joint part 5', and the effect in that case is the same as described above.

Although the information recording substrate capable of two-sided recording using 9 and 9' as the recording layer has been described, it goes without saying that it may have only one of 9 and 9'.

As explained above, according to the method for manufacturing an information recording substrate of the present invention, in the manufacturing method in which two substrates each having a recording medium are bonded via a spacer, unevenness is formed on the corresponding portions of the spacer and the bonding surface of the substrates. By creating a fitting part and performing ultrasonic welding within it, a completely airtight bonding layer with no shibin holes can be obtained. It is possible to prevent condensation caused by pinholes and deterioration of the medium caused by gas from the adhesive.

Furthermore, the conventional problem of deterioration of the recording medium due to the adhesive extruding from the bonding layer (including the adhesive) and defects in appearance are eliminated, so this method is extremely effective for the production method of air sandwich type information recording substrates.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an example of a conventional information recording substrate, FIG. 2 is a diagram showing an example of a method for manufacturing an information recording substrate by ultrasonic welding, and FIG. 3 is a cross-sectional view of an example of a conventional information recording substrate. It is a partial detailed sectional view. In the figure, 1.1', 8.8', 16.16',
18°18' and 2°3, 23' are the substrates, 2,2
' and 9,9' are recording media, 3.3', 10.10'
, 13.21 and 25, 25' are spacers, 4 is a hollow layer, 5 is a base, 6°6' and 15 are annular projections, 7 is a horn, 11.11'. 17.19 and 26, 26' are annular grooves, 12.12
', 14°22, and 24.24' are annular plates, and 20 is a sloped plate. O I Figure O 2 Figure 73 Figure 7i-4 Figure 71-5 Figure O 6

Claims (1)

[Claims] 1. A disk substrate having a recording layer on which information is written and exposed by light, with the recording layer inside, and the inner and outer edges of the disk substrate are both laminated in parallel via a spacer. In the method for manufacturing an information recording substrate with a sandwich structure, an annular groove is formed in the bonded part of either the disk substrate or the spacer surface, and a monkey-shaped ridge that matches the annular groove is formed in the other bonded part. form the above-mentioned smooth surface.