JPH10188356A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need for use of adhesives over the entire part of substrates of an optical recording medium, such as DVD, formed by joining two sheets of the substrates by fixing two sheets of the substrates by a system to fit the substrates to each other in non-recording regions, thereby putting the substrates into a joint state. SOLUTION: Cylindrical recessed parts 23 are molded at three points at 120 deg. intervals in the non-recording regions on the inner peripheral side of the polycarbonate substrate 10 and hook parts 17 are molded at three points at 120 deg. intervals in the non-recording regions on the outer peripheral side. Projections 13 consisting of cotter pins are molded on the inner peripheral side of the other polycarbonate substrate 20. Recessed parts are molded on the outer peripheral side in such a manner that the hook parts 17 are detained. Guide grooves and pits are formed on the recording surface side of the respective polycarbonate substrates 10, 20 and vapor deposited aluminum layers 11, 21 are formed thereon. Further, the surfaces are covered with protective layers 12, 22, by which the respective substrates 1, 2 as the recording medium are manufactured. These substrates 1, 2 are superposed on each other and are fitted and fixed at six points in total.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium in which two substrates are joined, and more particularly, to an optical recording medium in which the two substrates are joined by a specific method.

[0002]

2. Description of the Related Art In general, today's optical recording media are in the form of disks, and are read-only disks (CD-Audio, CD-
ROM), a laser disk (LD), a recordable disk (CD-R), and a disk (MD, MO, PD or CD-RW) capable of erasing and rewriting the recording have been developed.

Further, recently, a so-called DV is used in which two disks are bonded so that their recording surfaces are on the inside.
D (digital video disc or digital versatile di
sc) was developed and commercialized. This DVD is
The substrate is usually made of polycarbonate, and is manufactured by bonding two substrates with an ultraviolet curable resin or a hot melt adhesive.

In such a bonding method, in order to prevent uneven bonding, it is necessary to apply an adhesive uniformly without mixing air bubbles to achieve uniform bonding. The bonding equipment can be expensive and complicated. Further, in order to facilitate the uniform application, an adhesive having a relatively low viscosity is used. However, since the viscosity is low, the fluidity is large, and the adhesive is applied to the disk during the adhesive application or the substrate bonding step. There is a possibility that it will protrude from the center or the outer periphery of the disk.

[0005] Further, in a medium (for example, DVD-9) of a type in which there are two recording layers and the information in the recording layer is read from only one side of the disk, the information is taken into consideration in consideration of the transparency of the adhesive and the like. There is also a constraint that an adhesive that does not adversely affect the reading of the data must be selected.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to have a recording layer on at least one side of at least one of two substrates, and to join the two substrates with the recording layer inside. An object of the present invention is to provide an optical recording medium which is free from the above-mentioned problems caused by the adhesive.

[0007]

Means for Solving the Problems The present inventor has conducted intensive studies in order to achieve the above object, and as a result, when joining substrates, when joining by a fitting method instead of using an adhesive, The inventors have found that the above-mentioned problems can be solved, and have completed the present invention. That is, the invention according to claim 1 is characterized in that two substrates are fixed in a non-recording area by a fitting method to be in a joined state.

[0008] The fitting method in the present invention refers to a form in which a part of one substrate and a part of the other substrate are directly fitted and fixed, and two substrates are connected via a third member. It also includes a form of fitting and fixing. The invention according to claim 2 is characterized in that, as the fitting portion, a protrusion is provided on one substrate, and a concave portion corresponding to the protrusion is provided on the other substrate. here,
The projection and the recess are fixed by frictional force of each other (Claim 3) or locked by a hook provided on the projection and fixed (Claim 4).

Further, in the invention according to claim 5, a hook extending as a fitting part to surround an end of one of the substrates and to surround an end of the other of the substrates, and locking the end of the other substrate. A part is provided. The invention according to claim 6 is characterized in that each part of the two substrates is fitted and fixed via a third member. Here, it is preferable that the third member straddles the ends of the two substrates and is fitted and fixed to each substrate by a projection and a recess (claim 7).

[0010] On the other hand, the invention according to claim 8 is characterized in that the fitting portions are provided in the non-recording areas on both the inner peripheral side and the outer peripheral side. More preferably, at least three fitting portions are provided in the non-recording area on the inner peripheral side and at least three in the non-recording area on the outer peripheral side. When the optical recording medium has a disk shape, the fitting portion of the outer non-recording region does not exist on a straight line extending from the center of the disk and passing through the fitting portion of the inner non-recording region. (Claim 10).

In the invention according to the eleventh aspect, if only the fitting portion is characterized by using an adhesive for the fitting portion, it may be a non-recording area and may be caused by the adhesive. There is no problem, but rather a stronger joint can be obtained by using an adhesive together.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. First, the fitting method will be exemplified below. (1) As shown in FIG. 1 or FIG. 2, protrusions 13 and 14 are provided on one substrate 1 as fitting portions, and recesses 23 and 24 corresponding to the protrusions are provided on the other substrate 2 to form protrusions 13. , 14 and recess 23,
And 24 are fixed with each other's frictional force.

In the embodiment (1), it is preferable that the design is such that the frictional force between the projection and the concave portion is large. That is, it is preferable that the outer diameter of the protrusion is slightly larger than the inner diameter of the recess, and a certain amount of pressure is applied to fit the protrusion into the recess. The projection 13 in FIG. 1 is a so-called split pin (cylindrical shape having a partly slit), and since elasticity is generated at the pin portion, the recess 13 is formed with a relatively small pressure.
23, and the strength of engagement can be increased. (2) As shown in FIG. 3 or FIG. 4, protrusions 15 and 16 having a hook portion are provided on one substrate 1 and concave portions 25 and 26 corresponding to the protrusions are provided on the other substrate 2 as fitting portions. The projection
The hooks 15 and 16 and the recesses 25 and 26 are locked and fixed by hooks provided on the projections 15 and 16 side. (3) As shown in FIG. 5 or FIG. 6, the fitting portion extends to the end of one substrate 1 so as to surround the end of the other substrate 2 and engages the end of the other substrate 2. Hook portions 17 and 18 for stopping are provided. (4) As shown in FIG. 7, each part of the two substrates 1 and 2 is fitted and fixed via a third member 30.
The member 30 straddles the ends of the two substrates 1 and 2 and is fitted and fixed to each of the substrates 1 and 2 by a projection (hook portion) and a concave portion.

Next, a description will be given of the fitting and fixing points. In any of the above cases (1) to (4), the fitting and fixing must be achieved in the non-recording area on the inner circumference or outer circumference of the disc, but the hooking is performed as in the above (3) or (4). It is desirable that the above method be performed on the outermost periphery of the disk. On the other hand, aspects such as the above (1) or (2) can be achieved on both the inner circumference and the outer circumference of the disk.

The place for fitting and fixing may be only the non-recording area on the inner side (see FIG. 8) or only the non-recording area on the outer side (see FIG. 9). In consideration of the fitting and fixing, it is preferable to set both the inner peripheral side and the outer peripheral side. In FIGS. 8 to 11, a dot indicates a fitting portion. Further, as shown in FIG. 10, the number may be at least three in the non-recording area on the inner peripheral side and at least three in the non-recording area on the outer peripheral side. When assuming a straight line extending from the center of the disc to the outer peripheral direction through each fitting portion of the non-recording area on the inner peripheral side, the fitting part of the non-recording area on the outer peripheral side does not exist on the straight line. It is better to do. This is for dispersion. This applies to the case where there are four or more fitting portions on the inner peripheral side and the outer peripheral side, respectively, as shown in FIG.

In any case, an adhesive may be partially used in the fitting portion in order to achieve stronger bonding.

[0017]

Next, a more specific embodiment will be described with reference to FIG. However, the present invention is not limited to this embodiment. Two polycarbonate substrates 10 and 20 were produced by molding. On one of the polycarbonate substrates 10, three cylindrical recesses 23 as shown in FIG. 1 are formed at 120 ° intervals in the non-recording area on the inner circumference side.
Hook portions 17 as shown in FIG.
The arrangement pattern is as shown in FIG.

On the other side, the other polycarbonate substrate 20 is provided with a cotter pin as shown in FIG. (Hereinafter referred to as a split pin) 13 and a concave portion (see FIG. 5) formed on the outer peripheral side so that the hook portions 17 are locked. Note that the outer diameter of the split pin 13 is slightly larger than the diameter of the cylindrical concave portion 23 that accommodates the split pin 13.

Of course, each polycarbonate substrate 10, 20
On the recording surface side, guide grooves and pits are formed, on which aluminum deposited layers 11 and 21 are formed, and further covered with protective layers 12 and 22, so that each of the substrates 1 and 2 as an optical recording medium is formed. Is prepared.
Then, these two substrates 1 and 2 were superimposed and fitted and fixed at a total of six points to produce a DVD.

As a result, a good bonding state was obtained.

[0021]

As described above, according to the first aspect of the present invention, it is not necessary to use an adhesive over the entire substrate.
An optical recording medium in which the two substrates are firmly joined is obtained.
In other words, it is possible to provide an optical recording medium in which the fundamental problems caused by the adhesive, such as uniform application of the adhesive, uneven bonding, mixing of air bubbles into the adhesive, and protrusion of the adhesive have been solved.

According to the second aspect of the present invention, a protrusion is provided on one of the substrates and a recess is provided on the other of the substrates as a fitting portion. It is possible (claim 3), and if it is locked and fixed by the hook portion, the reliability is increased (claim 4). According to the fifth aspect of the present invention, the hook portion extending from the end of one substrate and locking the end of the other substrate can be securely fixed as the fitting portion.

According to the sixth aspect of the present invention, the third aspect
It can be securely fixed by fitting and fixing through the members of
In particular, it is preferable that the third substrate is fixed across the ends of the two substrates (claim 7). On the other hand, according to the invention according to claim 8, the fitting portion can be securely fixed by providing the fitting portion on both the inner peripheral side and the outer peripheral side. Item 9). In addition, if the outer peripheral side fitting portion is disposed on a straight line extending from the center of the disk and passing through the inner peripheral side fitting portion, the fitting portion is dispersed and good.
0).

According to the eleventh aspect of the present invention, an adhesive is used for the fitting portion. However, if only the fitting portion is used, the problem due to the use of the adhesive may be caused by a non-recording area. A stronger bond is obtained without any occurrence.

[Brief description of the drawings]

FIG. 1 is a diagram showing an aspect (1) -1 of a fitting method.

FIG. 2 is a diagram showing an aspect (1) -2 of a fitting method;

FIG. 3 is a diagram showing an aspect (2) -1 of a fitting method;

FIG. 4 is a diagram showing an aspect (2) -2 of a fitting method;

FIG. 5 is a diagram showing an aspect (3) -1 of a fitting method.

FIG. 6 is a diagram showing an aspect (3) -2 of a fitting method;

FIG. 7 is a diagram showing an aspect (4) of a fitting method;

FIG. 8 is a diagram showing a layout example of a fitting portion;

FIG. 9 is a diagram showing a layout example of a fitting portion;

FIG. 10 is a diagram showing a layout example of a fitting portion.

FIG. 11 is a diagram showing a layout example of a fitting portion.

FIG. 12 is a sectional view of the embodiment.

[Explanation of symbols]

 1, 2 Substrate 10, 20 Polycarbonate substrate 11, 21 Aluminum evaporation layer 12, 22 Protective layer 13 Protrusion (split pin) 23 Recess 14 Protrusion 24 Recess 15 Protrusion (with hook) 25 Recess 16 Protrusion (with hook) 26 Recess 17 Hook Part 18 Hook part 30 Third member

Claims (11)

[Claims] 1. An optical recording medium having a recording layer on at least one surface of at least one of two substrates, wherein the two substrates are joined to each other with the recording layer inside. In a non-recording area by a fitting method to form a bonded state. 2. A projection is provided on one of the substrates as a fitting portion,
2. The optical recording medium according to claim 1, wherein a concave portion corresponding to the protrusion is provided on the other substrate. 3. The optical recording medium according to claim 2, wherein said projection and said recess are fixed by a frictional force of each other. 4. The optical recording medium according to claim 2, wherein the projection and the recess are locked and fixed by a hook provided on the projection. 5. A fitting portion, wherein a hook portion is provided at an end of one substrate so as to surround an end of the other substrate and locks an end of the other substrate. The optical recording medium according to claim 1, wherein 6. The optical recording medium according to claim 1, wherein each part of said two substrates is fitted and fixed via a third member. 7. The light according to claim 6, wherein the third member straddles the ends of the two substrates and is fitted and fixed to the respective substrates by protrusions and recesses. recoding media. 8. The optical recording medium according to claim 1, wherein the fitting portions are provided in the non-recording areas on both the inner peripheral side and the outer peripheral side. 9. The optical recording medium according to claim 8, wherein at least three fitting portions are provided in a non-recording area on the inner peripheral side and at least three in a non-recording area on the outer peripheral side. 10. The optical recording medium has a disk shape, and a fitting portion of the outer non-recording area exists on a straight line extending from the center of the disc and passing through a fitting portion of the inner non-recording area. The optical recording medium according to claim 8, wherein the optical recording medium is not set. 11. The optical recording medium according to claim 1, wherein an adhesive is used for the fitting portion.