JPS61192046A - Optical recording medium - Google Patents

Abstract

PURPOSE:To easily prepare and seal a recording layer without possible damage of grooves during preparing the recording layer by integrating the flexible substrate covered with a recording layer consisting of coloring matter or color compounds and a protection plate with grooves in the surface which are put together with a projecting part of grooves of the protector plate come in rigid connection with the recording layer. CONSTITUTION:A disc-shaped flexible substrate 2 with a hole 7 at the center for the shaft carries a recording layer 4, which in turn carries a protection plate 3 with grooves 31 whose projecting part 35 are rigidly connected with a flexible substrate 2 via the recording layer 4. As a result of grooves provided in the recording layer 4, the projecting part of the protector plate 3 and the flexible substrate 2 carrying the recording layer 4 are integrated into an optical recording medium 1. Recording sections on the recording layer 4 located in the grooves of the protection plate 3 do not contact the protection plate 3 and sealed in an enclosed room, and serve as the recording tracks, to which incident light for writing and reading is normally given through the flat rear face of the protection plate 3.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field: Background of the Invention The present invention relates to an optical recording medium, particularly a heat mode optical recording medium.

For example, optical recording disks have the characteristic that the recording disk does not deteriorate due to wear and tear because there is no contact between the medium and the writing or reading head.For this reason, research and development of various optical recording media have been conducted. There is.

Among such optical recording media, heat mode optical recording media are being actively developed because they do not require development in a dark room.

This heat mode optical recording medium is an optical recording medium that uses recording light as heat. For example, a part of the medium is melted or removed with recording light such as a laser, and it is called a bit. There is a bit forming type in which writing is performed by forming a small hole, information is recorded using this bit, and reading is performed by detecting this bit with a readout light.

Until now, most of these pit-forming type disks, especially those using a semiconductor laser as a light source, which can reduce the size of the device, have a recording layer made of a material mainly composed of Te.

However, in recent years, Te-based materials have been found to be harmful, and there is a need for higher sensitivity.

Due to the need to lower manufacturing costs, Te
There are an increasing number of proposals and reports on media that use organic material-based recording layers mainly containing one dye (Patent Application No. 59).
In such optical recording media, it is necessary to seal and protect the recording layer to prevent foreign matter such as dust and dirt from adhering to the surface of the recording layer formed on the substrate. There is.

In this case 1, for example, in an optical recording medium in which the recording layer is sealed by using a protective plate made of resin or the like and bringing the flat surface of the protective plate into close contact with the surface of the recording layer, the S/N ratio and sensitivity etc. may decrease. This causes the inconvenience of being lost. Therefore, it is preferable for such an optical recording medium to have a so-called air sandwich structure as shown in FIG.

In FIG. 3, the substrate 2 is usually formed from a rigid body such as acrylic resin.

The recording layer 4 formed on the substrate 2 is a coating film containing a dye or a dye composition, and is usually formed by spinner coating.

A protection plate 3 is provided on the inner and outer peripheries of the substrate 2 via ring-shaped spacers 5 and 6 so as to face the flat surface of the recording layer 4 formed on the substrate 2 in a substantially parallel manner. The recording layer 4 is fixedly integrated with the substrate 2 and hermetically sealed.

The surface of the substrate 2 on which the recording layer 4 is formed is usually provided with a groove 31 consisting of a groove in the shape of a spiral or ring-shaped recess in order to perform writing, reading, etc. while performing tracking control. ing.

Therefore, when a recording layer is formed on the surface of the substrate 2 having the grooves 31 by spinner coating, the grooves may be damaged due to the solvent etc. contained in the coating composition for the recording layer. A problem has arisen.

Further, the spinner coating method itself is a so-called batch coating method, and its productivity is significantly inferior to the continuous gravure coating method used in the production of general tape-shaped magnetic recording media.

II. OBJECTS OF THE INVENTION In view of the above-mentioned circumstances, the present invention aims to prevent damage to grooves that occurs when forming a recording layer.

Moreover, it is an object of the present invention to provide an optical recording medium in which the recording layer can be easily formed and sealed, and the productivity is extremely high.

■Disclosure of invention Such objects are achieved by the invention described below.

That is, the present invention has a recording layer made of a dye or a dye composition on a flexible substrate, and the groove convex portion of a protective plate having grooves formed on the surface is fixed and integrated with the recording layer. This is a characteristic optical recording medium.

■Specific structure of the invention Hereinafter, a specific configuration of the present invention will be explained in detail.

Preferred embodiments of the optical recording medium of the present invention are shown in FIGS.
As shown in the figure.

The optical recording disk 1 has a recording layer 4 formed on a disk-shaped flexible substrate 2 having a hole 7 in the center into which a rotating shaft is inserted, and the flexible substrate 2 further has a groove on one surface. The groove convex portion 35 of the protection plate 3 formed with the groove 31 is fixed and integrated with the recording layer 4 interposed therebetween. Alternatively, two of these integrated devices may be used, and the flexible substrates may be glued together to integrate them, or a recording layer may be provided on both sides of the flexible substrate 2, and this and two protection plates may be integrated. Good too.

Further, to explain the present invention in detail, the flexible substrate 2 is made of polyester (PET), vinegar HC/l/loin, polyethylene, polypropylene, AS resin, ABS.
Various known resins such as resin, thermoplastic resin such as polyvinyl chloride, polyurethane, phenol resin, epoxy resin, acrylic resin, thermosetting resin such as polyimide may be used, but usually polyester (PET), Preference is given to using cellulose acetate.

Such a flexible substrate 2 typically has a weight of 12 to 500 gm
In this embodiment, the disc shape has an outer diameter of about 8 to 30 cm, but the shape etc. may be appropriately determined depending on the purpose and use and is not particularly limited.

A recording layer 4 made of one dye or a dye composition is provided on the flexible substrate 2.

The dye to be used may be appropriately determined from among those that effectively absorb the writing light and reading light depending on the wavelengths of the writing light and reading light. In this case, the light source for these light sources is:
Since it is preferable to use a semiconductor laser because the device can be made smaller, one dye is a cyanine-based, phthalocyanine-based,
Anthraquinone type, azo type, triphenylmethane type, pyrylium or thiapyrylium salt type, etc. are preferred.

Further, when a single dye composition is used as a recording layer, a self-oxidizing resin such as nitrocellulose, or a thermoplastic resin such as polystyrene or nylon can be contained. Furthermore, in order to prevent oxidative deterioration of one dye, a quencher may be included. Furthermore, other additives may also be included.

In such a case, a mixture of an indolenine cyanine dye and a quencher such as bisphenyldithiol is particularly preferred.

It is also preferable to use these as an ionic combination of a cation of a dye and a 7-ion of a quencher, or a mixture of this and a dye.

The recording layer is formed on a series of flexible films that are continuously conveyed, and the above-mentioned mixture contained in the recording layer is coated with ketone type, ester type, ether type, aromatic type, alkyl halide type, etc. It is sufficient to add one or more solvents such as alcohol and apply gravure coating, etc. After that, by punching into a predetermined shape, a flexible substrate 2 having a predetermined shape and having a recording layer 4 can be obtained. .

The recording layer 4 may have a thickness of 0.01 NN10IL, and preferably has a thickness of 0.05 to 0.1 pm.

Compared to conventional spinner coating, gravure coating is extremely productive and suitable for continuous processes.

The protection plate 3 is integrated with the flexible substrate 2 having the recording layer 4 during fixation for the purpose of sealing and protecting the recording layer 4 .
Such a protection plate 3 has a hole 7 in the center into which a rotating shaft is inserted.
It has a disk shape that is approximately the same shape and size as the above-described flexible substrate 2, and is made of resin that is substantially transparent (preferably transmittance of 80% or more) to writing light and reading light. . This allows writing and reading from the back side of the protection plate 3 where the groove 31 is not provided.

The resin material used may be acrylic resin, polycarbonate resin, nylon, polymethylpentene, epoxy resin, PS, PMMA, AS resin, ABS resin, polyvinyl chloride, or the like.

On one smooth surface of the protection plate 3, a recess-shaped groove for tracking, a so-called groove 31, is provided in a spiral or ring shape. Note that the outer shape of the protection plate 3 and the arrangement shape of the tracking recesses may be determined as appropriate depending on the purpose of the purpose, and are not particularly limited, as in the case of the flexible substrate 2 described above.

The depth of the groove 31 may be such that the groove is not buried during integration. Usually, the depth is about 0.05 to 0.1 m. Further, the width of the groove is approximately 0.81 Lm.

The convex portions formed on the surface of the protective plate 3 as a result of providing the grooves 31 having such a concave shape on the surface of the protective plate 3 are similar to the flexible substrate 2 on which the recording layer 4 is formed. They are fixed and integrated to form the optical recording medium 1 of the present invention.

By such a forming method, the recording portion of the recording layer 4 located in the recessed portion of the protection plate 3 can be sealed with a gap without coming into close contact with the protection plate 3.

Then, such a recording part is used as a recording track part,
The writing light and the reading light are normally irradiated from the smooth back surface side of the protective plate 3.

With this configuration, the writing sensitivity and the reading S/N ratio are improved, and the tracking control signal is also increased.

The flexible substrate 2 on which the recording layer 4 is provided may be fixed and integrated with the protection plate 3 by a method such as fusion using ultrasonic waves or the like. In this case, the flexible substrate 2 and It is necessary to select materials for the protection plate 3 that can be fused together. If the recording layer contains a dye, it has good thermocompression bonding properties.

Also, on the adhesive surface of the convex portion of the protection plate 3 and/or on the recording layer 4
An adhesive layer may be provided between the flexible substrate 2 and the flexible substrate 2 and fixed by fusing.By doing this, the range of usable material combinations is expanded.

Note that the protection plate 3 usually has a certain degree of thickness and rigidity.

Although it is preferable to use a rigid substrate such as resin or glass,
A flexible substrate may be used if necessary.

(2) Specific Effects of the Invention In the optical recording medium of the present invention, for example, writing light is irradiated from the back side of a protective plate while rotating. As a result, bits are formed in a track shape in the recording track portion of the recording layer located in the groove recessed portion of the protection plate.

The bits formed in this manner are detected, for example, by irradiating readout light from the back side of the protection plate while rotating and detecting the reflected light.

In addition, in order to control tracking, 1. Normally, while writing and reading, the reflected light is divided,
Introduce it to a pair of sensors divided into two. At this time, when the beam spot begins to deviate from the recording track section, the primary light due to the interference effect due to the phase difference due to the step of the groove is biased toward one sensor, so the signals from both sensors are detected.
A track error signal is detected.

Note that if the recording layer is formed from a dye or a dye composition containing a thermoplastic resin, once formed bits can be erased by light or heat and aged again.

In addition, the light source used for writing and reading is
Although various lasers can be used, it is particularly preferable to use a semiconductor laser.

■Specific Effects of the Invention According to the present invention, groove convex portions of a protective plate having a recording layer made of a dye or a dye composition on a flexible substrate and grooves formed on one surface are recorded. is fixed and integrated with the flexible substrate to form an optical recording medium.

Therefore, there is no problem such as groove damage caused by solvents contained in the recording layer, which has conventionally occurred, and the recording layer can be easily formed by a continuous process such as gravure coating.

Furthermore, since the recording layer is sealed without causing the recording portion to come into close contact with each other, there is no decrease in sensitivity.

Furthermore, since groove precision is not required, it is advantageous in manufacturing.

Also, compared to the conventional so-called air sandwich structure,
The overall thickness of the recording medium can be made thinner, and the strength is also high.
Also, uneven rotation during operation is less likely to occur.

Therefore, since the optical recording medium of the present invention has a configuration that is extremely easy to manufacture compared to the conventional air sandwich structure, productivity is significantly improved and the quality of the product is also excellent. .

[Brief explanation of drawings]

FIG. 1 is a cut end view showing an embodiment of the optical recording medium of the present invention. FIG. 2 is a cut end view showing the optical recording medium of FIG. 1 before assembly. FIG. 3 is a cut end view showing an example of a conventional optical recording medium. Explanation of symbols 1... Optical recording medium, 2... Flexible substrate.

Claims (1)

[Claims] (1) A recording layer made of a dye or a dye composition is provided on a flexible substrate, and the groove convex portion of a protective plate with grooves formed on the surface is fixed and integrated with the recording layer. optical recording medium.