JPS63119034A - Information recording medium - Google Patents

Abstract

PURPOSE:To replace suitably a protecting layer with a new protecting layer and to keep recording medium in the initial normal performance by providing a transparent protecting layer, which can be replaced, at an optical beam incident side in the medium. CONSTITUTION:On the surface of an optical disk, a separatable transparent thin film or a protecting layer 34 such as a film are stuck, thickness t' of the protecting layer 34 is much thinner than thickness (t) of a disk substrate 31, and made into the thickness in which a sufficient permeability is obtained to the wavelength of a laser light made incident on the disk substrate. When a scratch 35 is stuck, the thin film or the protecting film 34 such as a film are separated, a new thin film or a protecting film 36 such as a film are covered again and the optical disk can be corrected to the complete original condition. As the means to cover the thin film or the protecting film 36 such as a film, the protecting film 36, for example, is stuck by a modacrylic emulsion, and then, the film can be easily separated in accordance with the necessity and the sufficient sticking force can be kept at the time of using.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an information recording medium such as an optical disk or an optical cart, and relates to an information recording medium that can repair scratches etc. on the surface of the medium. .

(Prior Art) Examples of information recording media that record or reproduce information by irradiating light include optical discs and optical carts.

These recording media generally consist of a substrate, a recording layer provided on this substrate, and a protective layer for protecting this recording layer. The light passes through and is irradiated onto the surface of the recording layer. Therefore, these substrates or protective layers are made of transparent plastic such as acrylic or polycarbonate, glass, or the like so that the incident light beam can pass through them. Furthermore, since the above-mentioned information recording media are generally compact and easy to attach and detach from a playback device and to replace, they tend to be handled carelessly when increasing the number of media. Therefore, there is a high possibility that dirt, scratches, etc. may adhere to the surface of the medium.

(Problems to be Solved by the Invention) However, as described above, when dirt, scratches, etc. adhere to the surface of the recording medium, nine various problems occur.

This point will be explained using an optical disc as an example and referring to a PjSA diagram. FIG. 4 is a schematic cross-sectional view of a conventional optical disc.

As shown in the figure, a recording layer 12 is provided on the lower surface of the optical disk substrate 11. R indicates the radial direction of the optical disc. In the figure, the reason why the recording layer 12 has an uneven cross section in the radial direction R is that the recording layer 12 is provided with groups for improving the tracking angle. A laser beam 13 emitted from a laser light source (not shown) is transmitted through the substrate 11 while being converged by an objective lens 17 and the like, and reaches the recording layer 1.
2, and predetermined information is recorded as a bit string. When reproducing this recorded information, the reflected light that is reflected by the recording layer 12 and returns to the objective lens 17 again from among the light beams irradiated onto the recording layer 12 as described above is used. The amount of this reflected light is
It is changed depending on the presence or absence of the bit above 2. Recorded information is reproduced by detecting this change in light amount.

By the way, on the surface 14 of the optical disc as described above, there is a mark 15 in the figure.
If a scratch as shown in is generated, the laser beam 13 is scattered at the polarized portion, so the amount of laser beam 13 incident on the recording fileZ is reduced. 15, the laser beam 13 reaching the recording layer 12 is modulated.
During reproduction, when the laser beam 13 is incident and reflected,
The influence of the scratch 15 is experienced twice, and as a result, the S/N ratio of the reproduced signal deteriorates.

The above-mentioned inconveniences occur not only when large scratches are deposited on the optical disk surface, but also when relatively small scratches or dirt are deposited on the surface of the optical disk. It is easy to restore the normal optical disc properties by wiping off even the slightest stains, but after long-term use,
Minor scratches, dirt, etc. gradually remain as roughness on the disk surface, and the transmittance of the laser beam 13 gradually deteriorates.

Furthermore, depending on the degree of damage, recorded information may not be reproduced correctly.

(Means for Solving the Problems) The above problems can be solved by installing a replaceable transparent protective layer on the light beam incident side of the information recording medium that records or reproduces information by irradiating it with light. The problem is solved by an information recording medium characterized by the following.

(Function) As mentioned above, since the protective layer is replaceable, the protective layer can be replaced with a new protective layer as appropriate depending on the degree of scratches or dirt, and the recording medium will return to its original normal performance. can be recovered.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of an embodiment of an information recording medium according to the present invention. Note that this embodiment is explained using an optical disc.

In FIG. 1, 31 is an optical disk substrate, and 32 is a recording layer provided on the surface of the optical disk substrate. The thickness of the optical disk substrate shown in the middle of FIG. Further, R indicates the radial direction of the optical disc. Note that the unevenness of the recording layer 32 is a group provided concentrically on the optical disc. A protective layer 34 such as a peelable transparent thin film or film is attached to the surface of such an optical disc. The thickness t' of the protective layer 34 is much thinner than the thickness t of the disk substrate 31, and is set to a thickness that provides sufficient transmittance for the wavelength of the laser light incident on the disk substrate.

If a scratch 35 as shown in FIG. 2(a) is attached to the surface of the optical disk, as shown in FIG. As shown in b), by covering the protective film 36 again with a new thin film or film, the optical disc can be completely restored to its original normal state.

In addition, as mentioned above, the protective film 3 such as a thin film or film
As a means of covering the adhesive layer 6, if the adhesive layer 36 is applied using, for example, an acrylic emulsion, it can be easily peeled off as needed, and sufficient adhesion can be maintained during use.

Although the embodiments described above have been described with respect to optical discs, they can also be applied to other recording media, such as optical carts.

Next, there is one invention. An example of application to an air sandwich type optical disc will be described with reference to FIG.

FIG. 3(a) is a partially cutaway perspective view of the air sandwich type optical disk, and FIG. 3(b) is a 312(a)
), and FIG. 3(C) is a partially enlarged sectional view of FIG. 3(b).

In these figures, an upper substrate 51 is provided on a lower substrate 52 with a spacer 54 in between.

Reference numeral 55 indicates a hollow portion between the upper and lower substrates 51 and 52. A recording M53 is provided on the hollow portion 55 side of the lower substrate 52.

In such an optical disc, a laser beam 56 emitted from a laser light source (not shown) is incident from an upper substrate 51 toward a lower substrate 52, passes through the upper substrate 51, and enters the recording layer 53 of the lower substrate 52. It is forced to irradiate. When reproducing information recorded on the recording layer 53, the incident laser beam 56 as described above is used to record W! It is reflected by I53 and passes through the upper substrate 51 again. Therefore, the laser beam 56 is particularly scattered by the scratches 57 attached to the surface of the upper substrate 51, and the amount of light incident on the recording layer 53 is reduced.

Therefore, in this embodiment, the upper substrate 51 is configured to be easily replaced as necessary. That is, if the upper base 51 is attached to the spacer 54 using an acrylic emulsion or the like used in the above embodiment, the upper base 51 can be easily removed when replacing the spacer. Furthermore, when attaching a new upper substrate 51, it is similarly attached to the spacer 54 using an acrylic emulsion or the like.

(Effects of the Invention) As explained above, in the information recording medium of the present invention, a replaceable transparent protective layer is provided on the light beam incident side. The surface of the 11-layer protector is the most susceptible to scratches and scratches during use.
Since this is the part where dirt or the like adheres and affects the light incident on the recording surface, if the protective layer is replaced with a new protective layer as appropriate, the recording medium can maintain its initial normal properties.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of an optical disc according to an embodiment of the present invention, and FIG. 2(a) is a schematic sectional view showing a situation where a scratch has occurred on the surface of the optical disc shown in FIG. 1. FIG. 2(b) is a schematic cross-sectional view showing the optical disc in FIG. 2(b) with a new adhesive layer 11 attached;
FIG. 3(a) is a partially cutaway perspective view showing another embodiment of the present invention, FIG. 3(b) is an enlarged sectional view of the notch in FIG. 3(a), and FIG. C) is a partially enlarged view of the cross section shown in FIG. 3(b), 4U:! i is a schematic cross-sectional view of a conventional optical disc, and FIG. 5 is a diagram showing a situation where a scratch has occurred on the surface of the optical disc shown in FIG. 4. 31... Substrate, 32... Recording layer, 34... Protective layer. 35... Scratch, 36... New 3 layers of protection. Agent Patent Attorney Minoru Yamashita Figure 1 Figure 3 (a (b) (C) Figure 4 Figure 5

Claims (3)

[Claims] (1) An information recording medium for recording or reproducing information by irradiating light, characterized in that a replaceable transparent protective layer is provided on the light beam incident side of the medium. (2) The information recording medium according to claim 1, wherein the protective layer is a peelable thin film or sheet-like protective film provided on the light-transmitting surface of the medium. (3) The information recording medium according to claim 1, wherein the protective layer is a flat substrate provided on a base having a recording layer via a spacer.