JPH10134417A - Optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk which enables a user to easily identify either a surface A or a surface B merely by viewing its appearance. SOLUTION: This optical disk has a disk substrate 3 which is formed with pit patterns 3b based on information signals on one surface, a reflection layer 3a which is so formed as to cover its surface, a disk substrate 4 which is formed with pit patterns 4b based on the information signals on its one surface, a reflection layer 4a which is disposed to cover its surface and a binder layer 5 which binds the disk substrates 3, 4 in the state of disposing these substrates opposite to each other. The colors of the reflection layer 3a and the reflection layer 4a are varied from each other to enable the identification of the surface A and the surface B of the optical disk from a difference in the color of the reflection layers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk, and more particularly, to a pair of substrates having an uneven pattern formed on one surface thereof based on an information signal, such that one surface of the substrates is opposed to each other. Related to optical disks.

[0002]

2. Description of the Related Art Various types of optical discs for recording information signals such as digital audio signals and video signals and optically reproducing the information signals are known. Among them, for example, a read-only optical disk called a compact disk has a light-transmitting disk substrate having a concave / convex pattern formed on one surface based on a digital audio signal, and one surface of the disk substrate. It is composed of a reflective layer provided to cover the uneven pattern and a protective layer provided to cover the reflective layer.

[0003] On the protective layer, information such as an album title, an artist name, and a song name recorded on the disk is printed using silk printing or the like. The user can visually check the information recorded on the optical disc by the information such as the title and the song title printed on the protective layer. At the same time, the user recognizes that the surface opposite to the surface on which printing is performed is the information reading surface.

Recently, an optical disk called a digital video disk has been proposed. This digital video disc has a thickness of 0.6 mm and a diameter of 120 mm.
By bonding together a disk substrate having a light transmitting property. These one disk substrate has an uneven pattern based on a digital video signal like the compact disk described above, and a low reflection layer is provided so as to cover the uneven pattern.

A digital video signal recorded on the disk substrate is an MPEG-2 (Motion Pict).
ure Expert Group Phase 2)
, And after being modulated by the 8-16 modulation method, an error correction code is added. Then, the reflection layers provided on the disk substrate are bonded to each other using a highly sensitive ultraviolet-curable resin or a sheet-like member having adhesiveness so that the reflection layers are back to back.

[0006] As in the case of the compact disc described above, 2
The two disk substrates are bonded together. As a matter of course, after forming a protective layer for protecting the reflective layer, it may be bonded using an ultraviolet curable resin or the like as described above. Also in that case, they are bonded so that the entire thickness becomes 1.2 mm. Further, it is also possible to form a digital video disk by forming an uneven pattern on one disk substrate only based on a digital video signal and using the other disk substrate as a so-called dummy substrate having both flat surfaces. Conceivable.

In this case, a reflective layer is provided on one surface of the other disk substrate, and the two disk substrates are bonded so that the reflective layers are back to back. Also in this case, it is needless to say that a protective layer for protecting the reflective layer may be formed and then bonded so that the protective layers are back to back.

However, in the digital video disk substrate described above, it cannot be determined which surface is the front surface (hereinafter, referred to as A surface) or the rear surface (hereinafter, referred to as B surface). Because both sides A and B have the same color, the user may know that a disc must be actually mounted on the reproducing apparatus or the recording / reproducing apparatus and information read from the disc on the apparatus side. Can not.

Also, unlike the above-mentioned compact disk, the above-mentioned digital video disk has a surface on both sides on which a light beam emitted from the optical head of the apparatus is incident. It is difficult to provide a display on the surface of the disk for use in discriminating the side B and the side B. Therefore, does the user just look at the external appearance of the digital video disc A-side,
It is not possible to determine whether it is the B side.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and it is easy for a user to easily determine whether the surface is A or B by simply looking at the appearance of the disk. It is an object of the present invention to provide an optical disc that can be easily identified.

[0011]

According to a first aspect of the present invention, there is provided an optical disk comprising: a first substrate (disk substrate) having an uneven pattern (pit pattern) formed on one surface based on an information signal; A first reflective layer provided so as to cover the surface of the first substrate on which the uneven pattern is formed, a second substrate having an uneven pattern based on an information signal formed on one surface, and the second substrate And a second reflective layer provided so as to cover the surface on which the uneven pattern is formed, and one surface side of the first substrate and one surface side of the second substrate are joined in a state where they face each other. A joining means (coupling layer) is provided, the first reflection layer and the second reflection layer have different colors, and the A and B surfaces of the optical disc are determined based on the difference in the colors of the first and second reflection layers. Can be determined.

According to a fifth aspect of the present invention, an optical disk covers a first substrate having an uneven pattern based on an information signal formed on one surface, and a surface of the first substrate having the uneven pattern formed thereon. Reflection layer provided as described above, and a second reflection layer formed on one surface with an uneven pattern based on an information signal.
Substrate, a second reflective layer provided so as to cover the surface of the second substrate on which the concavo-convex pattern is formed, one surface side of the first substrate and one surface side of the second substrate And a joining means for joining in a state where the first and second substrates are opposed to each other. The first substrate and the second substrate have different colors from each other. The side B can be determined.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical disc according to the present invention will be described in detail with reference to the drawings. In each of the embodiments described below, a read-only digital video disk on which a digital video signal is recorded will be described as an example of an optical disk. First, a read-only digital video disk according to the first embodiment will be described.

First Embodiment A read-only digital video disc (hereinafter simply referred to as a disc) 1 according to a first embodiment has an overall thickness of 1.2 mm and a diameter of 1, as shown in FIG. But almost 120
mm, and a center hole 2 is formed at the center. The center hole 2 is used for positioning the disk 1 by engaging with the centering portion of the disk constituting the disk rotation mechanism of the apparatus when the disk 1 is loaded in the reproducing apparatus.

As shown in FIG. 2, the disk 1 comprises a pair of disk substrates 3, 4 and a coupling layer 5. The disk substrate 3 and the disk substrate 4 are formed into a disk shape having a substantially uniform thickness, for example, 0.6 mm by injection molding using a synthetic resin material having a light transmitting property such as polycarbonate. Openings for forming the center hole 2 are formed in the centers of the disk substrates 3 and 4, respectively. On one surface of each of the disk substrates 3 and 4, pit patterns 3b and 4b are formed as concavo-convex patterns based on digital video signals as information signals. The digital video signal recorded on the disc 1 is the M video signal described above.
It is compressed by PEG2 and modulated by the 8-16 modulation method.

The digital video signal encoded by such a method is recorded, for example, from the inner peripheral side of the disk substrate 3 toward the outer periphery of the disk substrate 3 and the disk substrate 4 has the outer periphery of the disk substrate 3. Recording is continued from the outer peripheral side or the inner peripheral side of the disk substrate 4 continuously to the recording end.

Reflection layers 3a, 4a are formed on the surfaces of the disk substrates 3, 4 on which the pit patterns 3b, 4b are formed so as to cover the pit patterns. As shown in FIG. 2, these reflective layers 3 a, 4 a are connected directly to the inner peripheral part and the outer peripheral part of the disk substrate 3, and are directly connected to the inner peripheral part and the outer peripheral part of the disk substrate 4 by the coupling layer 5. 3 where the reflective layers 3a and 4a are not formed
c, 4c, 3d, and 4d are formed. That is, the reflective layer 3a is formed of a metal material such as aluminum by a sputtering method or a vapor deposition method in a state where the inner peripheral portion and the outer peripheral portion of the disk base 3 are masked.

The reflection layer 4a is made of, for example, gold.
a, a metal substrate having a color different from that of the reflective layer 3a and having substantially the same reflectance as the reflective layer 3a, that is, a metal substrate having a color different from that of the reflective layer 3a when viewed by a user. 4 is formed by a sputtering method or a vapor deposition method in a state where the inner peripheral edge portion and the outer peripheral edge portion are masked.

The disc substrate 3 and the disc substrate 4 are joined to each other by bonding the reflection layers 3a and 4a together with an adhesive such as an ultraviolet-curing adhesive or a bonding layer 5 made of a double-sided adhesive sheet. Make up. At this time, as described above, the disk substrate 3 and the disk substrate 4
Since the reflective layers 3a and 4a are not provided on the inner peripheral edge portions 3d and 4d and the outer peripheral edge portions 3c and 4c,
The disk substrates 3 and 4 are directly coupled to each other. As a result, the inner and outer peripheral ends of the reflective layers 3a and 4a do not directly contact the outside air, so that the reflective layers 3a or 4a can be prevented from being deteriorated by oxidation or the like.

Although the cross section of the disk 1 shown in FIG. 2 is exaggerated for the sake of clarity, the disk 1 has an overall thickness of 1.2 mm as described above. The thicknesses of 3a, 4a and the bonding layer 5 are extremely thin.

Incidentally, the disk substrates 3 and 4 constituting the disk 1 according to the above-described first embodiment include a reflective layer 3a,
4a are directly connected to each other by the bonding layer 5, but these reflecting layers 3a, 4a are formed on the reflecting layers 3a, 4a.
May be formed by forming protective layers made of an ultraviolet-curable resin for protecting the optical disk 1 and then bonding these protective layers to each other using the bonding layer 5.

As described above, in the disk according to the first embodiment, information signals are recorded on both surfaces of the disk by changing the colors of the reflection layers 3a and 4a provided on the disk substrate 3 and the disk substrate 4. Even in the case of a so-called double-sided disk, the user needs to read the data recorded on the disk by mounting the disk 1 in a playback device and playing back the disk 1 and then confirm which side of the disk is the surface. Disk 1
It is possible to easily determine which surface is A or B.

As a modification of the first embodiment, as shown in FIG. 3, the reflection layers 3a and 4a
Marks 7, 8 indicating the disc 1 on the inner peripheral side of the disc 1, that is, outside the information recording area where the above-mentioned information signal is recorded, that is, on the non-recording area 4d inside the innermost circumference where the pit pattern starts. Can also be provided. As shown in FIG. 3, the mark 7 is formed by adding a letter “A” along the periphery of the center hole 2 at a predetermined distance from the bar code 6 indicating the date of manufacture, stamper number, lot number, and the like. The provision of this number indicates that this surface is the so-called A surface of the disk 1.

As shown in FIG. 4, the mark 8 is formed by separating the alphabet "B" from the bar code 6 indicating the date of manufacture, the stamper number, the lot number, etc. by a predetermined distance. The surface is indicated by the so-called B surface of the disk 1 by providing a plurality of the surfaces along the line. These marks 7 and 8 are provided on the disk substrates 3 and 4 by the reflection film 3.
When forming a and 4a, the bar code 6 and the bar code 6 can be formed in advance on an inner peripheral mask that masks the inner peripheral side of the disk substrate.

According to this modification, in addition to the fact that the color of the reflective layer is different, the user can easily and accurately check the surface of the disk by seeing the pattern of the marks "A" and "B". can do.

Second Embodiment Next, a pit pattern according to a second embodiment of the present invention will be described with reference to FIG. It is to be noted that the same parts as those in the first embodiment are denoted by the same reference symbols, and detailed description thereof is omitted. The disk 10 has a pair of disk substrates 13 and 14 as in the first embodiment described above. Each of the disk substrates 13 and 14 has an opening defining the center hole 2 similarly to the disk substrates 3 and 4 according to the first embodiment. Disk substrate 1
Of the discs 3 and 14, the disc substrate 13 is formed by injection molding using a light-transmitting synthetic resin material such as polycarbonate into a disk having a substantially uniform thickness, for example, 0.6 mm and a diameter of about 120 mm. I have.

The disk substrate 14 has a particle size of 50
Almost uniform thickness by injection molding using polycarbonate mixed with a dye of μm or less, for example, 0.6 mm in thickness
And is formed in a disk shape having a diameter of approximately 120 mm.
This disk substrate 14 disperses the dye in a dispersion medium,
Coarse particles are removed by a filter to prepare a liquid colorant having a maximum particle diameter of the dye of 50 μm or less, and the liquid colorant is supplied to a resin input hopper of an injection molding machine to be injection molded to be formed. For example, the disk substrate 14
Is

43 parts by weight of Brastron Red 830 (anthraquinone-based dye: manufactured by Arimoto Chemical Co., Ltd.) 55 parts by weight of Mitsui PS Green BH (anthraquinone-based dye: manufactured by Mitsui Toatsu Co., Ltd.) Dye: Mitsubishi Chemical)
After preliminarily mixing 2 parts by weight of the dye with the acrylic plasticizer, the particles of the dye are dispersed while being refined with three rolls, and then filtered by a filter to be mixed with polycarbonate as a paste colorant and injected. It is formed as a jet-black black disk substrate by molding with a molding machine.

The block error rate can be reduced by reducing the particle size of the dye mixed in the polycarbonate to 50 μm or less. As the dye to be mixed into the polycarbonate as a substrate material for forming the disk substrate 14, besides anthraquinone-based and heterocyclic-based dyes, methine-based, verinone-based, berylen-based, and thioindigo-based dyes may be used alone or in combination of two or more. And a pigment other than the dye may be used. As the vehicle for dispersing the dye, epoxy plasticizers such as phthalate ester plasticizers such as diisodecyl phthalate, etc. A mixture of the above can be used.

On one surface of each of the disk substrates 13 and 14, a pit pattern is formed as an uneven pattern based on a digital video signal as an information signal. The digital video signal is compressed by MPEG2,
-16 modulated. The digital video signal encoded by such a method is recorded, for example, from the inner peripheral side of the disk substrate 13a to the outer periphery of the disk substrate 13 and is recorded on the disk substrate 14 at the recording end of the outer peripheral of the disk substrate 13 Continuous disk substrate 1
4 is continuously recorded from the outer peripheral side or the inner peripheral side.

Reflection layers 13a and 14a are formed on the surfaces of the disk substrates 13 and 14 on which the pit patterns are formed so as to cover the pit patterns. As in the case of the disk 1 according to the first embodiment, the reflection layers 13a and 14a are formed such that the inner and outer peripheral portions of the disk substrate 13 are directly connected to the inner and outer peripheral portions of the disk substrate 14. Reflective layer 13 as bonded by bonding layer 5
parts 13c, 14c, 1 where a and 14a are not formed
It is formed so that 3d and 14d can be provided.

That is, the reflection layers 13a and 14a are formed by sputtering or vapor deposition of a metal material such as aluminum while the inner and outer peripheral portions of the disk substrates 13 and 14 are masked. These disc substrates 13 and 14 are joined by the joining layer 5 such that the reflection layers are back to back like the disc 1 according to the first embodiment described above.

The disk 10 according to the second embodiment shown in FIG. 5 is exaggerated for easy understanding.
Actually, as described above, the disk 10 according to the second embodiment is also formed so as to have an overall thickness of 1.2 mm similarly to the disk 1 according to the first embodiment.
The thicknesses of the reflection layers 13a and 14a and the coupling layer 5 are extremely thin.

The disk substrates 13 and 14 of the disk 10 according to the second embodiment have a configuration in which the reflection layers 13a and 14a are directly coupled to each other by the coupling layer 5. Similar to the first embodiment, these reflection layers 13a, 14a are formed on the reflection layers 13a, 14a.
May be formed by forming protective layers made of a UV-curable resin for protecting the disk 10 and then bonding these protective layers to each other using the bonding layer 5. Further, the disk 10 according to the second embodiment is also similar to the modified example shown in FIGS.
By providing the marks 7 and 8 in the non-recording area of the disk 10, the user can more accurately determine the surface of the disk 10 in addition to the difference in color of the disk substrate.

In each of the embodiments described above, a digital video disk of a read-only type has been described as an example. However, the present invention is not limited to this, and can be applied to a recordable digital video disk.

The disk 10 according to the second embodiment includes:
Since the disc substrate 13 side is transparent and the disc substrate 14 side is black, the user loads the disc 10 into the reproducing apparatus and plays back the disc 10 without reproducing the disc 10.
It can be easily visually confirmed which surface the surface is.

In each of the above-described embodiments, a digital video disk using a disk substrate formed of a synthetic resin material having optical transparency has been described as an example. However, for example, a glass disk substrate is used. An optical disk may be used. In this case, a UV curable resin is applied to one surface of a flat glass disk substrate, and in this state, the UV curable resin is pressed against the stamper, and the concave and convex pattern of the stamper is transferred to the UV curable resin. What is necessary is just to make the material of the reflective layer provided on the ultraviolet-curable resin to which this uneven pattern is transferred different. Thereafter, if the reflection layers are bonded to each other so as to be back to back, a digital video disk similar to that of the first embodiment can be obtained.

Also, the glass constituting the disk substrate is colored in advance with a dye or the like, the concave and convex pattern of the stamper is transferred in the same manner as described above, a reflective layer is provided, and the reflective layers are back to back. By bonding as described above, a digital video disk similar to that of the above-described second embodiment can be obtained.

In the above-described embodiment, the reflection layer is formed on the inner side and the outer side of the disk substrate so that a portion without the reflection layer is formed so that the disk substrates are joined to each other by the direct bonding layer. Is provided between the position slightly inside the opening and the position inside the outer periphery of the disk substrate, but is provided from the inner periphery of the opening of the disk substrate to the outer periphery of the disk substrate, that is, over the entire surface of the disk substrate. You may do it. As described above, it is needless to say that the present application can be variously modified without departing from the gist of the main subject matter.

[0040]

According to the optical disk of the present invention, the first
From the difference between the colors of the reflective layers provided on the first and second substrates and the difference between the colors of the first substrate and the second substrate, the user self-views the optical disc with either A or B surface. It is possible to easily and accurately determine whether or not there is.

[Brief description of the drawings]

FIG. 1 is a perspective view of a read-only optical disc according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a read-only optical disc according to the first embodiment of the present invention.

FIG. 3 is a plan view of one side of a read-only optical disc according to a modification of the present invention.

4 is a plan view of the read-only optical disc shown in FIG. 3 as viewed from the other surface.

FIG. 5 is a sectional view of a read-only optical disc according to a second embodiment of the present invention.

[Explanation of symbols]

1, 10: disk (optical disk), 2: central hole, 3,
4, 13, 14 ... disk substrates, 3a, 4a, 13a,
14a: reflective layer, 3b, 4b: pit pattern, 3c,
4c, 3d, 4d, 13c, 14c, 13d, 14d ...
Area where the reflective layer is not provided, 5 ... bonding layer, 6 ... barcode, 7, 8 ... mark

Claims (6)

[Claims] 1. A first substrate having an uneven pattern based on an information signal formed on one surface, and a first reflection provided to cover the surface of the first substrate on which the uneven pattern is formed. A second substrate having an uneven pattern based on an information signal formed on one surface thereof; a second reflective layer provided to cover the surface of the second substrate having the uneven pattern formed thereon; A joining means for joining one surface side of the first substrate and one surface side of the second substrate so as to face each other, wherein the first reflection layer and the second reflection layer are provided. An optical disc characterized by having different colors from each other. 2. The first reflection layer is provided so as to cover a concavo-convex pattern formed on one surface of the first substrate and substantially cover the entire surface of one surface of the first substrate. And the second reflective layer is provided so as to cover the uneven pattern formed on one surface of the second substrate, and to cover substantially the entire surface of one surface of the second substrate. 2. The optical disk according to claim 1, wherein 3. The reflectivity of one of the first reflective layer and the second reflective layer is higher than the reflectivity of the other reflective layer. An optical disk according to claim 1. 4. The method according to claim 1, wherein one of the first reflection layer and the second reflection layer is formed of aluminum, and the other reflection layer is formed of gold. The optical disk according to claim 1, wherein 5. A first substrate having an uneven pattern based on an information signal formed on one surface, and a first reflection provided to cover the surface of the first substrate on which the uneven pattern is formed. A second substrate having an uneven pattern based on an information signal formed on one surface thereof; a second reflective layer provided to cover the surface of the second substrate having the uneven pattern formed thereon; Bonding means for bonding in a state where one surface side of the first substrate and one surface side of the second substrate face each other, wherein a color of the first substrate and a color of the second substrate are provided. An optical disc characterized by being different from each other. 6. The substrate according to claim 5, wherein at least one of the first substrate and the second substrate is formed of a synthetic resin material containing a dye. Optical disk.