JPS6020334A - Information carrier disk - Google Patents

Abstract

PURPOSE:To obtain a high-reliability optical information carrier disk while reducing an impulsive force applied to a sticking boundary surface by making one of two discoid susbstrates larger in external diameter until it is larger than the external diameter of an adhesive layer charged in the sticking boundary surface, and joining the two substrates together. CONSTITUTION:For example, a disk 11 is formed by providing a resin layer 3 which sets by ultraviolet-ray irradiation and has a track groove for laser light guidance and a recording mediumm layer 4 to a disk substrate 2 and sticking a protection substrate 6 through an adhesive layer 5; and the external diameter of the substrate is made a little bit larger than that of the substrate 6, and an adhesive is allowed to run round to outer circumferential surfaces 13 and 13' to join the substrates together. In another way, the outer circumferential surface 7 is made high intermediately and the highest part 15 is formed deviating from the adhesive layer and disk surfaces 9 and 9. Consequently, even if the disk 11 falls, no direct impact is applied to the sticking surface unlike a conventional end part and separation is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to two disk-shaped substrates having a recording medium layer on one side.
This invention relates to the structure of an information carrier disk (hereinafter simply referred to as a disk) made by laminating two sheets of information carrier disk.

Conventional structure and its problems The optical recording and reproducing method records and reproduces information by irradiating the recording medium layer of the disk with a laser beam corresponding to the information signal to create optical shading or unevenness on the recording medium layer. This method is capable of recording minute signals of several micrometers, and in principle enables high-density recording comparable to the wavelength of light. In addition, this optical recording and reproducing method does not transmit signals during recording or reproducing.

Since there is no contact between the pickup and the disk being played, there is no wear and tear, and it provides multiple functions such as still image and high-speed search, so it can be used for industrial purposes such as still image files and document files.
It is also being put into practical use for commercial purposes.

Conventionally, a recording medium layer is provided on one side of a disk-shaped transparent substrate, or a substrate on which a predetermined information signal is recorded as uneven bits is bonded to a protective substrate to form a disk, and the surface of the substrate is irradiated with laser light. It records and plays back information.

A conventional disk 1 is shown in FIG.

An ultraviolet curing resin layer 3 having trunk grooves for guiding laser light is provided on one surface of the disk substrate 2, and a recording medium layer 4 is further formed thereon.

In order to protect this recording medium layer 4, a protective substrate 6 is bonded to it via an adhesive layer 5.

After pasting together, the outer circumferential surface 7 of the disk 1 is formed into a medium-height shape. The highest part of the middle height formed on the outer circumferential surface 7 of the disk 1 and the adhesive layer 5 coincide with each other. Reference numeral 8 denotes a coating layer of a surface hardening material that protects the surface of the recording area, and is formed by being wrapped around the outer circumferential surface 7 of the disk substrate surface 9. 10 is a center hole which serves as the center of rotation during recording and reproduction.

The conventional disk configuration as described above causes the following problems. That is, after laminating, the outer circumferential surface of the disk 1 is formed into a medium height, and the center of the medium height is aligned with the adhesive layer 5. Therefore, when a mechanical impact is applied to the outer circumferential surface of the diskette 1 (for example, due to a fall), there is a risk that a large force will be applied to the bonded surface of the sheet due to the impact, resulting in peeling. In particular, if the disk 1 is dropped with its outer peripheral surface directly below, there is a high risk of peeling. In other words, this is because the impact force acts directly on the bonding interface. The reason why the outer circumferential surface of the disk 1 is formed to have a medium height is to make the surface hardening material smooth.

By applying this surface hardening material to the circumference of only the disk 1 to form a coating layer, the bonding strength of the outer circumference of the disk is improved, but this is still insufficient when subjected to the impact described above.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned problems, and aims to provide a reliable information carrier disk that reduces the impact force applied to the disk substrate bonding interface due to dropping or the like.

To J) of the invention: In the present invention, the outer diameter of at least one of the first and second disc-shaped substrates to be laminated is equal to the outer diameter of the adhesive layer filled in the bonding surface. By increasing the size, the impact force applied to the bonding interface of the lamination 9 can be reduced.

DESCRIPTION OF THE EMBODIMENT FIG. 2 shows a disk 11 in an embodiment of the present invention. In FIG. 2, the same parts as in FIG. 1 are given the same numbers. Reference numeral 2 shown in FIG. 2 is a disk substrate, and the outer dimensions are smaller than that of the protection substrate 6. As shown in FIG.

As in the conventional example, an ultraviolet curing resin layer 3 in which track grooves for a laser source system are formed is provided on a disk substrate 2, and a recording medium layer 4 is further formed.

In order to protect this recording medium layer 4, a protective substrate 5 is pasted together with an adhesive layer 4 interposed therebetween.

When bonding the protective substrates 6 together, an adhesive is applied to the outer peripheral edge of the bonding surface 12 to fill the bonding surface. It is still wrapped around the outer circumferential surface 13 of the disk substrate 1 and the outer circumferential surface 13' of the protective substrate 6.

The adhesive material that has wrapped around the outer circumferential surfaces 13 and 13' of the substrates is in a state as shown in FIG. 2 due to surface tension.

According to the above configuration, the outer peripheral surface 13°13' of the disk 11
Even if a mechanical shock is applied to the bonded interface, the structure is such that it is unlikely to peel off due to direct external force applied to the bonded interface. FIGS. 3a and 3b show the state of stress on the outer circumferential surface that occurs when a conventional disk 1 and a disk 11 according to an embodiment of the present invention are respectively dropped onto a floor surface 14, for example. In the above embodiment, unlike the conventional example, no impact is directly applied to the bonded interface, so the stress applied to the interface is small and peeling is less likely to occur.

In the above embodiment, a predetermined disk outer peripheral surface shape was obtained by bonding substrates with different outer diameter dimensions, but it may also be formed into a predetermined shape after bonding the substrates as in the conventional example.

A second embodiment is shown in FIG. As shown in FIG. 4, the outer peripheral surface 7 of the disk has a substantially truncated conical side surface shape.

As a result, when the disk is dropped as in the first embodiment, no impact is directly applied to the interface between the bonded surfaces, so the stress applied to the interface is small and peeling is less likely to occur.

In the method of configuring the disk outer circumferential surface 7 in the shape of a substantially truncated conical side surface, the respective substrates 2 and 6 which have been previously finished into a predetermined shape are prepared and bonded together. Alternatively, after pasting the sheets together, they are processed into a predetermined shape.

A third embodiment is shown in FIG. As shown in FIG. 5, the outer circumferential surface 7 of the disk has a middle height, and is located at a position offset from the highest portion 15, the adhesive layer 5 (bonding interface), and the disk surface 9.

As a result, when the disk is dropped as in the first embodiment, no impact is directly applied to the interface between the bonded surfaces, so the stress applied to the interface is small and peeling is less likely to occur. In the method of configuring the outer circumferential surface 7 of the disk in a mid-height shape, the disks are pasted together and then molded into a predetermined shape. Second. Since the outer circumferential surface of the disk in both the third embodiment is smooth, it is suitable for applying a surface hardening material.In particular, in the third embodiment, the outer circumferential surface of the disk has a middle height, and the highest part of the middle height is coated with an adhesive layer. And since it is located at a position offset from the disk surface,
As in the conventional example, a coating layer 8 made of a surface hardening material can be smoothly applied to the outer circumferential surface 7 of the disk as shown in FIG.

Effects of the Invention As described above, according to the present invention, peeling of the bonded interface caused by mechanical impact applied to the outer peripheral surface of the disk can be reduced, and a reliable information carrier disk can be easily obtained. be.

[Brief explanation of drawings]

FIG. 1 is a sectional front view of an information carrier disk in a conventional example.
FIG. 2 is a sectional front view of an information carrier disk in one embodiment of the present invention, and FIGS. 3a and 3b are FIG. 1. FIG. 2 is a sectional view of the end of the information carrier disk, FIGS. 4 and 5 are sectional views of the end of the information carrier disk in other embodiments of the present invention, and FIG. 6 is the sectional view of the end of the information carrier disk. FIG. 3 is a sectional view showing a state in which a surface hardening material is applied to the information carrier disk of the embodiment shown in FIG. DESCRIPTION OF SYMBOLS 11... Disc, 2... Disk substrate, 3... Ultraviolet curing resin layer, 4... Recording medium layer, 5... Adhesive layer, 6 ...protection board,
End, 13, 13'...Outer peripheral surface. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 ab Figure 4 Figure 5

Claims (3)

[Claims] (1) A first disk-shaped substrate and a second disk-shaped substrate are pasted together to form a disk, and the outer diameter of at least one of the first disk-shaped substrate and the second disk-shaped substrate is An information carrier disk with a larger outer diameter of the adhesive layer filled on the bonding surface. (2) The information carrier disk according to claim 1, wherein the outer circumferential surface of the disk has a substantially truncated conical side surface shape. (3) The information carrier disk according to claim 1, wherein the outer circumferential surface of the disk has a center height, and the center height is located at a position offset from the adhesive layer and the disk surface.