JPS63209040A - Optical recording carrier - Google Patents

Abstract

PURPOSE:To reduce influence of dust and flaws on a beam incident face on recording and reproducing by a defocusing effect by disposing a recording material layer near the rear face of a card. CONSTITUTION:The recording material layer 4 is formed on a transparent substrate 3 to which a preformat signal part 12 is previously provided. A hard coating layer 13 is provided in order to protect the recording material layer 4 against flawing and further, a hard coating layer 14 is provided on the surface of the transparent substrate 3 on the side where a luminous flux 7 enters for the similar purpose. The recording material layer for executing recording or reproducing is thereby disposed between the incident face of the light beam from the center of the thickness over the entire part of an optical recording carrier and the surface opposite therefrom and, therefore, the influence of the dust and flaws on the light incident surface on the recording pattern is decreased by the sufficient defocusing effect.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical record carrier, and more particularly to an optical information record carrier on which information is recorded or reproduced by irradiation with a light beam.

[Prior Art] In recent years, electronic file systems using compact discs and write-once discs, or erasable magneto-optical materials,
2. Description of the Related Art Commercialization and research and development of optical information recording and reproducing systems such as optical disk systems using phase change materials and the like are actively being conducted.

Recently, an optical card system that records and reproduces information on an optical record carrier in the form of a card, ie, an optical card, has been attracting particular attention. In any case, it is inevitable that optical information recording and reproducing carriers will become more widespread in the future, and it is thought that their current use mainly in offices will expand to include use in general households.

However, one of the drawbacks of optical information recording carriers is the occurrence of recording/reproducing errors due to dust or scratches on the surface of the recording carrier. In other words, dust and scratches cause light diffraction to scatter, causing flare in the light spot focused on the recording information surface.
This results in a loss of optical energy, causing recording errors and reproduction errors.

This will be explained below using the drawings.

Figure 6(a) shows the conventional optical card IJII! 6(b) is a sectional view taken along line AA.

The standard size of the optical card is called wallet size, which is the size of a credit card.

It is the same size as a cash card. (85,
6■-X 54.01mm x 0.77m5) An information recording area 2 is provided in a part of the optical card l, and this area is irradiated with semiconductor laser light focused to a diameter of several microns, Record and play back information.

The structure of the optical card is such that an adhesive 5 is placed between a transparent substrate 3 (for example, about 0.35 m thick) such as a transparent laminate plate such as polycarbonate and an opaque substrate 6 (for example, about 0.35 m thick). A recording material layer 4 is pasted therebetween.

For example, the recording material for an optical card proposed by Drexler Corporation of the United States is a specially treated ordinary 35-coated silver halide photographic film.

The optical card having the conventional configuration described above has the following drawbacks. That is, the distance from the recording material M4 to the light incident surface of the optical card (the surface of the transparent substrate 3 in FIG. 6) is 0.
．． Since it is small, about 35 to 0.41, the influence of dust and scratches on the light incident surface is large.

Conventionally, measures to improve these problems include hard coating the surface of the optical card, antistatic treatment, installing a protective cover, and handling the optical card in a cassette case.

Among these measures, the most effective method is to use a cassette case, but in the case of optical cards, the most attractive feature, ease of carrying, is compromised. In particular, since optical cards are characterized by being able to be carried in wallets like ordinary CD cards, they are not desirable for use as new optical record carriers, which have recently become a hot topic.

[Problem to be solved by the invention] The present invention does not particularly require the use of a cassette case.

It is an object of the present invention to provide an optical record carrier which prevents errors in recording and reproducing information caused by dust or scratches adhering to the light incident surface of the optical record carrier and protects the recording area.

[Means for Solving the Problems] That is, the present invention provides a card-shaped optical record carrier in which a recording material layer for recording or reproducing is arranged such that a light beam is incident on the optical record carrier from the center of the entire thickness of the optical record carrier. This optical record carrier is disposed between a surface and an opposite surface.

In the present invention, the recording material layer is preferably arranged on the surface of the optical recording carrier opposite to the light beam incident surface or in the vicinity thereof.

Further, it is preferable that the recording material layer is formed in a gate shape on the surface of the optical record carrier opposite to the light beam incident surface from the surrounding surfaces.

[Function] In the optical record carrier of the present invention, in a card-shaped optical recorder, the recording material layer for recording or reproducing is located from the center of the entire thickness of the optical record carrier to the light beam incident surface. Since it is disposed between opposite surfaces, it is possible to reduce the influence of dust and scratches on the light incident surface on the recorded pattern by a sufficient defocusing effect.

The defocus effect can be briefly explained as the following phenomenon.

In FIG. 2, a light beam 7 from a light source such as a semiconductor laser is shown.
is focused by the objective lens 8 onto the recording material surface 9 as a minute spot. Now, if there is a foreign object 11 such as dust or scratches on the surface lG of the transparent substrate, if the size of the foreign object 11 is the same as or larger than the spread of the luminous flux on the surface lO, then all the luminous flux will be is affected by the foreign matter 11 and cannot be focused on a minute spot.However, if the surface is on the surface 11' which is farther away than the recording material surface 9, the light beam spreads! The influence of the foreign object 11 on the light beam becomes part of the luminous flux, and the influence is reduced.

[Examples] Hereinafter, the present invention will be described in more detail based on examples shown in the drawings.

FIG. 1 is a sectional view showing an example of the structure of an optical record carrier of the present invention. In FIG. 1, the optical record carrier of the present invention has a preformatted signal section (tracking, track,
A recording material layer 4 is formed on a transparent substrate 3 provided with track numbers (track numbers, etc.) 12.

As the recording material layer 4, a thin film of an organic dye, metal, metalloid, or a composite thereof, which is conventionally known as a heat mode recording material, can be applied.

Examples of organic dyes include polymethine dyes such as cyanine, naphthoquinone dyes, dithiol metal complexes, and phthalocyanine pigments. The metal or metalloid is a low melting point substance such as Bi, Sn, Te, etc., or a substance containing As, Se, S, 0. Composite compounds etc. in which C and the like are bonded can be applied.

To form a thin film on the transparent substrate 3, depending on the material used, a solvent coating method such as spinning, roll coater, or dipping, or a vacuum film forming method such as evaporation, beam sputtering, or high-frequency sputtering is selected as appropriate. I can do things. In any case, the present invention is not limited to these recording materials, as is clear from its purpose.

Further, a hard coat layer 13 may be provided for the purpose of protecting the recording material layer 4 from scratches as much as possible, and furthermore, a hard coat layer 14 may be provided on the surface of the transparent substrate 3 on the incident side of the light beam 7 for the same purpose. Further, an auxiliary layer may be provided between the recording material layer 4 and the heart coat layer 13 for the purpose of protecting the recording material layer 4, adjusting recording sensitivity, etc.

The transparent substrate 3 is usually formed to have a thickness of about 0.4 to 1.2 am, preferably about 0.6 to 0.8 . Since the thickness of the material layer can be configured to be less than Ig■, the thickness of the optical recording carrier does not particularly increase.Of course, the above values are just an example, and the reason why the thickness of the entire card is specifically specified is However, considering that the card format is portable, it is desirable that it be around the ISO standard.

The transparent substrate 3 is preferably made of polycarbonate, polymethyl acrylate, or polyarylate, and the hard coat layer is preferably made of a heat or photocurable coating such as silicone, melamine, urethane, or acrylic.

By adopting the above configuration, when the thickness of the transparent substrate through which light passes, that is, the distance from the recording material layer to the light beam incident surface, is kept the same overall thickness compared to the conventional configuration. , it is possible to approximately double the amount.

The defocus effect can reduce the effects of scratches and dust.

Next, FIGS. 3(a) to 3(e) show the production process of the optical record carrier of the present invention. Next, the transparent substrate 3 is engraved with a mold 16 by a method such as injection, compression, or a photopolymer method. Transfer the preformat signal pattern that is The mold is manufactured using well-known techniques used for compact discs and video discs.

A recording material is applied to the transparent substrate 3 onto which the preformat pattern has been transferred to form a recording material layer 4, and then hard coat layers 13 and 14 are applied to both sides by a method such as sputtering, spinning, or dipping.

The optical record carrier is completed through the above steps. Furthermore, if necessary, it is possible to perform bordering, printing, etc. by printing.

Next, in the optical record carrier having the configuration shown in FIG. 1, since the recording material layer 4 is close to the back side of the card (the surface opposite to the light beam incident surface), the influence of scratches on the remote side is less likely to occur. It may easily reach the surface of the recording material. For example, if you hit the release surface with a sharp object, the surface of the recording material will swell. If a card is placed on a desk or other surface and is rubbed, it may be scratched by hard dust, foreign objects, etc. on the desk.

FIG. 4(a) shows a method for solving these drawbacks.

Optical record carriers having the configurations shown in FIG. 5(b) and FIGS. 5(a) and 5(b) can be used.

The configuration of the optical recording carrier shown in FIGS. 4(a) and 4(b) is such that a heart coat layer 14, a transparent substrate 3, a recording material layer 4, and a hard coat layer 13 are laminated in this order from the light incident side. .

The structures of the optical record carriers shown in FIGS. 5(a) and 5(b) are also almost the same.

The difference from the structure of the optical record carrier shown in FIG. 1 is that the back surface of the recording area section 15 is concave, so that even if the back surface of the recording area section 15 is placed on a desk or the like, it does not touch it directly. It is.

In FIGS. 4 and 5, the recording area portion is indicated by 15. Figure 4 shows a recording area shape suitable for an optical record carrier on which information is recorded and reproduced linearly, and Figure 5 shows a recording area shape suitable for an optical record carrier on which information is recorded and reproduced in a linear manner, and Figure 5 shows an optical recording area shape on which information is recorded and reproduced in a spiral or concentric manner, such as on a compact disc. This shows a card configuration having a recording area suitable for a record carrier.

It has been experimentally confirmed that it is effective if the level difference on the back surface between the recording area and other areas is about 0.11, and the distance between the recording material layer surface and the light beam incident surface is 1st
Although it is slightly different from the configuration shown in the figure, and the influence of dust and scratches on the entrance surface due to the defocus effect is also somewhat greater, it is a considerable improvement over the conventional configuration.

[Effects of the Invention] As described above, in the optical record carrier of the present invention, by arranging the recording material layer near the card release surface, dust and dirt on the beam incidence surface can be removed.
The influence of scratches on recording and playback can be reduced by the defocus effect. .

Further, the influence of scratches on the back surface side can be solved by making the back surface of the recording area part concave, thereby reducing the chance of direct contact, and creating a structure that is less susceptible to scratches. When the substrate is made of a polymeric material such as polycarbonate, the eight coat layer usually has a pencil hardness of about 2 to 3H.
Since it is not effective for all scratches, the effect of the present invention is particularly large.

As a result, there is no need to be particularly careful about carrying the optical record carrier, and the original characteristics of the optical record carrier can be fully demonstrated.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the optical record carrier of the present invention, and FIG.
The figure is an explanatory diagram of the defocus effect, Fig. 3(a) to ce>
4('a) is a plan view showing another example of the optical record carrier of the present invention,
FIG. 4(b) is a BBli sectional view, FIG. 5(a) is a plan view showing still another example of the precursor R1f1 body of the present invention, FIG. 6(a) is a plan view of a conventional optical record carrier, and FIG. 6(b) is a sectional view taken along the line AA. l... Optical card 2... Information recording area 3.
... Transparent substrate 4 ... Recording material layer 5 ... Adhesive material 6 ... Opaque substrate 7 ... Luminous flux
8...Objective lens 9...Recording material surface 10, 10'--Transparent substrate surface 11, 11'--Foreign matter 12--Preformat signal section 13, 14--Heartput layer 15- - Recording area section 16 - Mold

Claims (2)

[Claims] (1) In a card-shaped optical record carrier, the recording material layer for recording or reproducing is arranged between the light beam incident surface and the opposite surface from the center of the entire thickness of the optical record carrier. An optical record carrier characterized by: (2) The optical record carrier according to claim 1, wherein the recording material layer is formed on a surface of the optical record carrier opposite to the light beam incident surface to be more concave than the surrounding surface.