JPH07114748A - optical disk - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain an optical disc which is not deformed by heat shock and has scratch resistance. 1. An optical disc comprising a substrate 1 on which at least a recording layer 2 and a protective layer 4 are sequentially provided, and a polymer film layer 5 is provided on the protective layer 4 via an adhesive layer 6.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a CD, CD-R, CD
The present invention relates to optical discs used under the names such as PC (phase change type optical disc) and CD-MO (magneto-optical disc), and more particularly to improvement of their protection ability.

[0002]

2. Description of the Related Art Commercially available optical discs are, for example,
A recording layer and a reflective layer are provided on a substrate, an ultraviolet curable resin protective layer is provided on the substrate, and a label is provided on the protective layer by screen printing (for example, JP-A-2-7249).

Since the protective layer has a thickness of 10 μm or less, deformation of the reflective layer due to heat shock cannot be prevented and the recording pits are deteriorated. Furthermore, the label printing portion had a thicker protective layer than the other portions, so that the recording sensitivity was changed and the jitter was increased. In addition, the internal stress became non-uniform, and the signal deteriorated over time.

On the other hand, when a label is provided by screen printing, pressure is applied to the recording layer in the vertical direction during ink transfer,
Signal noise increased and an error occurred.

In addition, a magneto-optical (M
O) When the magnetic head used for recording is in contact with the protective layer when the magnetic head is stationary, if the contact surface is smooth, the floating during rotation is insufficient and there is a risk of head crash.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object thereof is to obtain an optical disk which is not deformed by heat shock and has scratch resistance.

[0007]

According to the present invention, firstly, in an optical disc in which at least a recording layer and a protective layer are sequentially provided on a substrate, a polymer film layer is formed on the protective layer via an adhesive layer. An optical disc provided is provided. In this case, so that the polymer film layer can be attached to the substrate,
A configuration in which the polymer film layer is attached to the substrate so as to cover each layer on the substrate is also preferable. Secondly, an optical disc having a label (visual information) printed on the polymer film layer is provided. In this case, the adhesive force between the polymer film layer and the pressure-sensitive adhesive layer is made weaker than the adhesive force between the protective layer and the pressure-sensitive adhesive layer to facilitate the peeling of the polymer film layer, and any label can be attached thereto. It is also preferable to do so. It is also preferable that the label is made of a thermochromic material so that the label information can be rewritten according to changes in the content. Thirdly, there is provided an optical disc in which the surface of the polymer film is roughened.

[0008]

In the first optical disk, the polymer film and the pressure-sensitive adhesive layer provided on the protective layer act as a double protective layer, so that the strength against heat shock and scratch resistance increases. Further, by peeling off the polymer film layer by sticking the polymer film layer and the substrate together to integrate them. In the second optical disc, since the label is printed on the polymer film layer, the recording layer is not damaged because it is not subjected to a strong pressure unlike the case where the label is provided by screen printing. Further, as described above, by providing the polymer film layer with peelability, it is possible to attach any label such as easy label replacement.
In addition, the label can be formed of a thermochromic material so that the label information can be rewritten, and thus the usability thereof can be expanded.
In the third optical disc, since the surface of the polymer film layer is roughened, head crush due to close contact of the flying magnetic head is eliminated and scratches can be prevented.

[0009]

EXAMPLES The present invention will be specifically described below with reference to examples. The comparative example and the example will be described in this order from the relationship of description.

Comparative Example 1 In FIG. 5, 1 is φ120
Injection-molded substrate 2 is a recording layer having a thickness of 400 Å coated with a cyanine dye on the substrate 1 by spin coating, 3 is an Au reflective layer sputter-deposited on the recording layer 2 to have a thickness of 800 Å, and 4 is An optical disk having a label 5 which is an ultraviolet curable resin layer provided on the reflective layer 3 by spin coating, having this structure as a blank disk, and further transferring the ultraviolet curable ink to the blank disk by screen printing and curing by ultraviolet rays. Got

Example 1 The blank disc and a polymer film 7 made of polycarbonate (PC) having a label 5 and having a thickness of 300 μm were attached to each other via an adhesive layer 6 with the label 5 inside. The optical disk according to the present invention was used (see FIG. 1). The label 5 may be an embossed pattern formed by embossing (see FIG. 2) or a hologram. Further, the label 5 may be formed of a thermochromic material so that the label information can be rewritten. Further, if a release agent is coated instead of the label, the user can attach a film having an arbitrary design and content. The optical disc manufactured as described above,
The recording layer was not deformed even when subjected to heat shock, and it also had scratch resistance.

The polymer film layer 7 may be not only a PC film but also a PET film, PMMA film, PP film or cellulose acetate or other cellulose film (paper) having a thickness of 100 to 500 μm. The pressure-sensitive adhesive layer 6 may be provided in a thickness range of 50 to 100 μm. Other recording layer 2 is not only a cyanine dye,
It may be provided with a phthalocyanine dye or a squarylium dye having a thickness in the range of 400 to 1000Å. The reflective layer 3 is made of Al, Ag or P instead of Au.
The thickness may be set in the range of 500 to 1000 Å depending on t or the like.

[Embodiment 2] In the blank disc, the recording layer 2 is replaced with a magneto-optical recording layer 20.
In place of the polymer film in
A magneto-optical disk was produced in the same manner as in Example 1 except that the PC film roughened to have a roughness of 100 μm was used (see FIG. 3). In FIG. 3, 8 is the unevenness of the film surface,
Reference numeral 9 is a magneto-optical head. In this disk, the flying magnetic head did not adhere to the disk surface, and head crash was prevented.

Example 3 In Example 1, as the polymer film, a film 70 having a larger diameter than that of the substrate 2 was used as shown in FIG.
The melted film and the substrate 2 were integrated by pressing with a ring-shaped cutter 30 (see FIG. 6) heated to ℃. In the case of this optical disk, the adhesion between the polymer film and the substrate was strong and the polymer film did not peel off.

[0015]

As described above, according to the optical disk of the present invention in which the polymer film layer is further provided on the protective layer through the pressure-sensitive adhesive layer, the protective layer is further laminated on the protective layer. Therefore, the resistance to heat shock increases,
Thermal deformation of the recording layer can be prevented, and scratch resistance can be improved. Further, the use of the label is expanded by the polymer film layer as described above, and the occurrence of head crush can be suppressed by using the polymer film having irregularities.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an optical disc of the present invention.

FIG. 2 is a cross-sectional view showing another example of the optical disc of the present invention.

FIG. 3 is a cross-sectional view showing still another example of the optical disc of the present invention and a usage state thereof.

FIG. 4 is a cross-sectional view showing still another example of the optical disc of the present invention.

FIG. 5 is a cross-sectional view showing a conventional optical disc.

FIG. 6 is an explanatory diagram of a method of integrating a polymer film and a substrate.

[Explanation of symbols]

 1 Substrate 4 Protective Layer 5 Label Part 6 Adhesive Layer 7, 70 Polymeric Film Layer 8 Unevenness on Film Surface 9 Magneto-Optical Head 20 Magneto-Optical Recording Layer 30 Ring Cutter 40 Heater

Claims (3)

[Claims] 1. An optical disc in which at least a recording layer and a protective layer are sequentially provided on a substrate, and a polymer film layer is provided on the protective layer via an adhesive layer. 2. The optical disc according to claim 1, wherein a label is provided on the polymer film layer. 3. The optical disc according to claim 1, wherein the surface of the polymer film layer is provided with irregularities.