JP2701396B2 - Optical recording medium - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a read-only optical recording medium, and more particularly to an optical recording medium capable of improving productivity and reducing costs. .

[Prior Art] Optical recording has advantages over magnetic recording in that a recording medium and a head are not in contact with each other and high-density recording is possible. As this optical recording medium, a read-only medium, an additionally writable medium, and an erasable / rewritable medium are known. As the read-only optical recording medium according to the present invention, an optical disk ( Compact discs), optical video discs, optical cards and the like have been put to practical use.

FIG. 3 is a cross-sectional view schematically showing a configuration example of, for example, an optical disc produced by a conventional manufacturing method. That is, a substrate 1 is prepared by injection molding or the like, and a metal film layer 2 is
Is provided. Further, a protective coat layer 3 is applied on the metal film layer 2, and a label print 4 is applied thereon. Reference numeral 5 denotes a center hole of the disk, and reference numeral 6 denotes a signal surface of information bits or the like.

[Problems to be Solved by the Invention] By the way, in the conventional optical disk, as described above, each disk is molded by injection molding or the like, and further, each of the disks is subjected to vapor deposition, protective coating, printing, and the like. Must be given. For this reason, expensive production equipment is required, and the product price is high. Also, the productivity of the disk is low, and it is not suitable for mass production. In other words, there is a limit to what mass productivity can be expected, and it is not particularly suitable for mass production on the scale of publications such as magazines and books, and material costs and equipment depreciation costs are high.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to provide an optical recording medium that is extremely inexpensive and has high productivity while significantly reducing material costs.

Means for Solving the Problems In order to achieve the above object, according to the present invention, a signal recording layer is provided on one surface of a first substrate made of a light-transmitting material,
In a read-only optical recording medium in which a signal is read from the other surface of the first substrate, a signal transmission surface of the first substrate is made of a light-transmitting material via an air layer. A second substrate is provided, and a signal is read through the first substrate, the air layer, and the second substrate.

[Operation] Therefore, in the optical recording medium of the present invention, the first substrate and the second substrate can be formed by conventional injection molding or the like, because different materials can be respectively selected and optimal materials can be selected. It is possible to improve the productivity and reduce the price as compared with a recording medium that is used.

Further, since the air layer is provided between the first substrate and the second substrate, the thickness of the second substrate can be reduced by the amount of the air layer, so that the material cost can be significantly reduced. Furthermore, since a thin film can be used as the first substrate, mass production by winding is possible.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view schematically showing a configuration example when the present invention is applied to an optical disc. In FIG.
On one surface of the first substrate 8 made of a light-transmitting material, a signal surface 9 for information bits or the like is formed. A metal film layer 10 is provided on the signal surface 9 by a method such as vapor deposition or sputtering. Further, a protective coat layer 11 is applied on the metal film layer 10, and a label print 12 is applied thereon. On the other hand, on the surface of the first substrate 8 opposite to the signal surface 9, that is, on the signal reading surface side, a second substrate 14 made of a translucent material is provided via a spacer 13. Then, an air layer 15 is provided between the first substrate 8 and the second substrate 14 so that signals are read through the first and second substrates 8 and 14. Reference numeral 16 indicates a center hole of the disk.

Here, as a material of the first substrate 8, a plastic sheet or a laminate thereof is generally used. For example, for example, a polyamide, polyester, polycarbonate, polymethyl methacrylate, methyl perten resin, ionomer resin, polyether sulfone, vinyl chloride, polystyrene, cellulose resin, or a laminate thereof is used. A resin (not shown in the figure) coated with a resin, a cellulose resin, an acrylic resin, or the like may be used. That is, this first
The material and configuration of the substrate 8 are selected according to the signal forming method. Further, the metal film layer 0 is provided for the purpose of reflection. Further, the protective coat layer 11
The material is not particularly limited, but needless to say that it does not corrode the metal film layer 10 and does not adversely affect signal reading. Used.

On the other hand, the material of the spacer 13 is not particularly limited, and generally, plastic, metal, or the like is used. The second substrate 14
The material and configuration of the first substrate 8 are selected from the same materials as those of the first substrate 8. However, basically, the first substrate 8 is selected by a signal forming method, while the second substrate 14 is selected. Since the material and configuration of the first substrate 8 are selected mainly from the viewpoint of signal surface protection, it is preferable to select, for example, a material having a higher plastic strength than that of the first substrate 8. In this case, the first substrate 8
It is natural that both the second substrate 14 and the second substrate 14 have low birefringence and do not hinder signal reading. As described above, examples of the material of the second substrate 14 include vinyl chloride resin, polyamide, polyester, polycarbonate, polymethyl methacrylate, methyl perten resin, ionomer resin, polyether sulfone, and polyphenylene sulfide resin. Further, as a method of joining the first substrate 8, the spacer 13, and the second substrate 14, a method of thermocompression bonding using a seal such as a heat seal or a fusing seal, a glue, a hot mate, an ultraviolet curable resin, or the like. Alternatively, a method of applying and bonding an adhesive such as a normal solvent-type adhesive or the like is appropriately selected. The overall thickness of the optical disk is usually 1.2 mm, for example, the thickness of the first substrate 8 is 0.3 to 0.4 mm, and the thickness of the spacer 13, that is, the air layer 15 is 0.1 mm.
The thickness of the second substrate 14 is set to 0.2 to 0.4 mm.

In the optical disk having such a configuration, the first substrate 8 and the second substrate 14 made of a light-transmitting material constitute the substrate of the disk.
Since it is possible to select different materials for each of the substrates 14 and to select the materials of the respective optimum materials, the productivity of the disk is higher than that of a disk made by conventional injection molding or the like,
Suitable for mass production. In addition, production equipment is inexpensive, and product prices are low. Further, the first substrate 8 and the second substrate 14
Since the air layer 15 is provided between the second substrate 14 and the second substrate 14, the thickness of the second substrate 14 can be reduced accordingly, and the material cost can be significantly reduced. Furthermore, since a thin film can be used as the first substrate 8, mass production by winding is possible.

As described above, the optical disk of the present embodiment has the metal film layer 10 on one surface of the first substrate 8 made of a translucent material.
In a read-only optical disk in which a signal is read from the other surface of the first substrate 8, an air layer 15 is provided on the signal reading surface of the first substrate 8 via a spacer 13. Forming a second substrate 14 made of a translucent material.
And the signal is read out through the first and second substrates 8 and 14, so that the material cost is remarkably reduced, and an optical disk that is extremely inexpensive and is most suitable for a small disk with high productivity. Can be.

It should be noted that the present invention is not limited to the above-described embodiment, but can be similarly implemented in the following manner.

For example, when a signal is to be formed on the first substrate 8 by winding, it is more convenient to use a thin substrate as the substrate. In such a case, a polyester resin film or the like is used. The second substrate 14 is made of polycarbonate resin or acrylic resin to suppress birefringence.

FIG. 3 shows that the second substrate 17 is formed by molding,
FIG. 2 is a diagram showing an example of a cross-sectional configuration in a case where a spacer 13 is omitted in the embodiment of the figure, and the same portions as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted. In this case, the second substrate
As the molding method 14, any of vacuum molding, injection molding, injection compression molding and the like may be used, and it is not particularly limited. However, it is only necessary to prevent birefringence from becoming strong.

On the other hand, in the above embodiment, the case where the present invention is applied to an optical disk has been described. However, the present invention is similarly applied to other optical recording media such as optical video disks and optical cards. You can do it.

[Effects of the Invention] As described above, according to the present invention, a signal recording layer is provided on one surface of a first substrate made of a light-transmitting material, and a signal is recorded from the other surface of the first substrate. In a read-only optical disk for reading data, a second substrate made of a light-transmitting material is provided on the signal reading surface side of the first substrate via an air layer, and the first substrate and the air are provided. Since the signal is read out through the layer and the second substrate, it is possible to provide an optical disk which is extremely suitable for a small disk which is extremely inexpensive and has high productivity because the material cost is significantly reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment in which the present invention is applied to an optical disc, FIG. 2 is a sectional view showing another embodiment of the present invention, and FIG. 3 is an example of a conventional optical disc. FIG. 8 First substrate, 9 Signal surface, 10 Metal film layer, 11 Protective coating layer, 12 Label printing, 13 Spacer, 14 Second
Substrate, 15 ... Air layer, 16 ... Center hole of disk, 17 ... Second
Board.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toshiharu Fujita 1-5-1, Taito, Taito-ku, Tokyo Inside Toppan Printing Co., Ltd. (56) References JP-A-60-242531 (JP, A) JP-A-2 -122443 (JP, A)

Claims (6)

(57) [Claims] 1. A read-only optical system in which a signal recording layer is provided on one surface of a first substrate made of a translucent material, and a signal is read from the other surface of the first substrate. In the recording medium, a second substrate made of a translucent material is provided on the signal reading surface side of the first substrate via an air layer, and a signal is transmitted through the first substrate, the air layer, and the second substrate. An optical recording medium characterized in that the optical recording medium is read. 2. The optical recording medium according to claim 1, wherein said first substrate and said second substrate are made of the same material. 3. The optical recording medium according to claim 1, wherein said first substrate and said second substrate are made of different materials. 4. The second substrate is formed by vacuum molding, injection molding,
2. The optical recording medium according to claim 1, wherein the optical recording medium is formed by injection molding or the like. 5. The optical recording medium according to claim 1, wherein said first substrate is made of a polyester resin coated with a polyurethane resin, and said second substrate is made of a polycarbonate resin or an acrylic resin. . 6. The optical system according to claim 1, wherein said second substrate comprises a flat portion and a side wall portion continuously and integrally molded. recoding media.