JPH0652579A - Optical recording element - Google Patents

Abstract

PURPOSE:To provide an optical recording element having high reliability by providing easy handling of the element in a step after a laminating step even if a laminating adhesive, a protective layer of a board is extended from the board. CONSTITUTION:An optical recording element D is provided by forming an optical recording medium 2 at least on one main surface of a board 1, and so laminating two media 2 of the board 1 as to be opposed with adhesive 4, and comprises a nonadsorptive coating layer 5 coating an outer periphery of the element D. Thus, adsorption of a clamper C, a cartridge case to an inner wall, etc., is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides an optical recording medium.
The present invention relates to improvement of an optical recording element in which a plurality of substrates are bonded together.

[0002]

2. Description of the Related Art Magneto-optical recording elements for recording / reproducing / erasing information have a single plate structure in which an optical recording medium or a protective layer is formed on one main surface of a transparent substrate. Alternatively, in order to further increase the recording capacity, two optical recording elements A and B having a single plate structure are used as shown in FIG. 3 to form an optical recording medium formed on substrates 11 of each optical recording element. There is generally known an optical recording element D0 which is adhered with an adhesive 14 so that 12 and 12 face each other. A protective layer 13 such as an ultraviolet curable resin is formed on each of the optical recording media 12 and 12.

Here, a hot melt type adhesive is generally used as the adhesive 14, but an optical recording element D0 produced by bonding two substrates 11 and 11 together is clamped on the outer peripheral surface and attached to a hub. , Built into the cartridge case,
When performing post-processing such as printing or inspection, there is a problem that the adhesive 14 protruding from the substrates 11 and 11 is adsorbed to the clamper C or the arm of the inspection device at the protruding portion 14a.

Further, in general, the optical recording element is often used in a state of being housed in a cartridge case, but at that time, there is a problem that the outer peripheral surface of the optical recording element is adsorbed to the inner wall of the cartridge case. .

For this reason, conventionally, the protruding portion 14a of the adhesive 14 is cut and removed together with the protruding portion 13a of the protective layer 13, but this makes the process complicated and
Oxygen, water vapor, etc. easily enter the optical recording medium from the cutting surface, causing deterioration of the optical recording medium and reducing the reliability of the optical recording element.

Even if the application process of the adhesive agent 14 is sufficiently controlled so that the adhesive agent 14 does not protrude, the substrate 11,
A protruding portion 13 a of the protective layer 13 is formed at 11. Since the protruding portion 13a has a large area and the ultraviolet curable resin or the like which is preferably used has a slight adhesiveness,
It is easily adsorbed on the clamper C etc., which makes handling inconvenient.

[0007]

Therefore, the present invention solves the above problems,
It is an object of the present invention to provide a highly reliable optical recording element by facilitating the handling of the optical recording element in the process after bonding even if the adhesive or the protective layer for bonding the substrate sticks out from the substrate.

[0008]

In order to achieve the above object, in the optical recording element of the present invention, at least an optical recording medium is formed on one main surface of a substrate, and two of these substrates are used as an optical recording medium. In the optical recording element bonded with an adhesive so as to face each other, a non-adsorptive coating layer is applied to the outer peripheral surface of the optical recording element.

[0009]

Embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, an optical recording element D applied to this embodiment is a disc-shaped and transparent substrate 1, 1 having a diameter of about 130 mm.
An optical recording medium 2 and an ultraviolet curable resin protective layer 3 are sequentially laminated on top of this, and substrates 1 and 1 are bonded together with a thermoplastic hot melt adhesive 4 so that the optical recording media 2 and 2 face each other. Have

Next, a preferred manufacturing example of the optical recording element D will be described. Using a substrate 1 of polycarbonate resin, a lower dielectric layer such as yttrium and sialon, a magnetic layer such as GdDyFe, and the like by magnetron sputtering.
Similarly, an upper dielectric layer such as yttrium / sialon and a reflective layer such as metal Al are sequentially laminated to obtain an optical recording medium 2. Here, the type of the optical recording medium 2 is arbitrary, and its layer structure is any known layer structure such as a layer structure having one of the dielectric layers and a layer structure having no magnetic layer. May be.

The surface of the optical recording medium 2 is spin-coated with an ultraviolet curable resin which is a copolymer of urethane acrylate and acrylic acid ester and is cured by ultraviolet rays to protect the protective layer 3.
(Film thickness 5 to 10 μm). Here, in the process of spin coating, the protective layer 3 drips from the substrates 1 and 1 and extends almost uniformly over the outer peripheral surfaces of the substrates 1 and 1. That is, the protruding portions 3a, 3a of the protective layer 3 extend substantially uniformly along the outer peripheral surface of the substrates 1, 1.

Next, the substrates 1 and 1 were adhered with a styrene / ethylene / butadiene / block copolymer type hot melt adhesive 4 ("XH598-6" manufactured by Hitachi Polymer; trade name). First, as shown in FIG. 2, while the substrate 1 is being fed by a belt conveyor or the like, the adhesive 4 is roll-coated on each of the two substrates 1 and 1 with an appropriate roller R (film thickness 25 to 50 μm).
m, film thickness after adhesion 50 to 100 μm). Next, the substrates 1 and 1 are stacked so that the optical recording media 2 face each other, and pressed and bonded. Here, a protruding portion 4a having a height (the protruding height in the diametrical direction from the outer peripheral surface of the substrate 2) of about 15 to 18 μm was formed during the pressing process. The protruding portion 4a has tackiness even after being bonded.

The outer peripheral surface of the optical recording element thus manufactured is wiped with Bencotton (cotton cloth) impregnated with silicone oil to form a coating layer 5 of silicone oil.
Was formed.

As shown in FIG. 1 in which the optical recording element is held by the clamper C, since the protruding portion 4a of the adhesive 4 is covered with the silicone oil coating layer 5, adsorption to the clamper C occurs. Absent.

The above-mentioned optical recording elements D1 to D3 were prepared using three kinds of silicone oils, and the adsorptivity to the clamper C was examined. Here, as the silicone oil, silicone oil 1 (KF96L) manufactured by Shin-Etsu Silicone Co.,
Silicone oil 2 (KF96) and silicone oil 3 (KF412) were used, and the results are shown in Table 1. In addition, D
No. 4 is a conventional example, in which the coating layer is not formed at all.

[0016]

[Table 1]

As is clear from Table 1, in the conventional example having no coating layer, the clamper C was adsorbed, whereas the optical recording elements D1, D2 and D2 having the non-adsorptive coating layer of silicone oil were formed. It was found that D3 did not adsorb to the clamper C at all. This is because the silicone-based oil is present between the clamper C and the protruding portion 4a of the adhesive 4, so that a molecule such as van der Waals force is present between the clamper C and the protruding portion 4a. It is probable that no interatomic force acted, resulting in no adsorption.

In this embodiment, the silicone-based oil is used as the non-adsorbing coating layer, but it is not limited to this. For example, stearic acid ester or alkali metal salt of fatty acid such as sodium fatty acid may be used. However, silicone-based oils are preferable because they are excellent in releasing property and weather resistance and heat resistance.

[0019]

According to the magneto-optical recording element of the present invention, since the non-adsorptive coating layer is formed on the outer peripheral surface of the optical recording element, the adhesive may stick out from the substrate when the substrates are bonded together. However, the influence of the adhesive is prevented as much as possible, and adsorption to the inner wall of the clamper, the cartridge case, etc. is eliminated, so that a highly reliable magneto-optical recording element can be provided. Further, the formation of the coating layer eliminates the conventional cutting step of the protective layer and the protruding portion of the adhesive, thereby preventing deterioration of the optical recording medium as much as possible.

[0020]

[Brief description of drawings]

FIG. 1 is a partial sectional view of a magneto-optical recording element according to the present invention.

FIG. 2 is a cross-sectional view showing how an optical recording element is roll-coated with an adhesive.

FIG. 3 is a partial cross-sectional view of a conventional magneto-optical recording element.

[Explanation of symbols]

1 ... Substrate 2 ... Optical recording medium 3 ... Protective layer 4 ... Adhesive 5 ... Covering layer D0, D ... Optical recording element

Claims (1)

[Claims] 1. An optical recording element in which at least an optical recording medium is formed on one main surface of a substrate, and two substrates are bonded with an adhesive so that the optical recording media face each other. An optical recording element having a non-adsorptive coating layer deposited on the outer peripheral surface thereof.