JPS62246783A - Optical recording medium - Google Patents

Abstract

PURPOSE:To reduce the error percentage of a regeneration signal at the time of reading, by forming an optical recording medium performing recording and regeneration using laser beam by laminating an optical recording layer, which is formed by successively laminating a beam absorbing layer, a recording auxiliary layer and a light reflecting layer, to a substrate. CONSTITUTION:A recording auxiliary layer 7 is interposed between a beam reflecting layer 6 and a beam absorbing layer 8 to laminate all of the layers 6, 7, 8 to form an optical layer 2a which is, in turn, provided on a substrate 3 so as to bring the beam absorbing layer 8 to a lower side and a protective layer 4 is provided as the outermost layer to form an optical recording medium. When laser beam 1 is allowed to irradiate the recording medium from the side of the recording layer 2a to perform the writing of information, a recording pit 5 is formed to the beam irradiation part of the optical recording layer 2a. The beam absorbing layer is constituted of a low m.p. metal or an organometal complex. As the recording auxiliary layer, a vinyl type resin such as polyvinyl chloride can be used and the reflecting layer is constituted by the vapor deposition of a metal or the coating of a vehicle having metal particles dispersed therein.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical recording medium on which information is optically written, reproduced and read.

[Prior Art] Conventionally, known optical recording media include types that generate pits (holes), types that form bubbles, and types that cause phase transformation when irradiated with a light beam, such as a laser beam.

Among these, those that form pits (pores) include low-melting point metals such as Te, Bi, Sn, Sb, and In, cyanine-based, squalium-based, phthalocyanine-based, tetradehydrocholine-based, and methine-based metals on the support. , naphthoquinone, benzenedithiol nickel complex, etc. (organic dye), and a thin film of a composite system of these organic dyes and metal.

These thin films are irradiated with a light beam, which is converted into thermal energy according to its absorption rate, and the heat moat forms recording pits.

The recording pit at this time is recording bit 5 as shown in Figure 3.
The periphery of the rim also rises, and a protrusion called a rim 9 is formed.

This rim is created by the melting-solidification process of the optical recording medium, but the process is very complex, and its shape and size are not always constant, leading to errors in the reproduced signal when reading. It became.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned conventional drawbacks, and to provide a light beam capable of forming recording pits with a constant size and shape without a small number of rims. It provides a recording medium.

Furthermore, an object of the present invention is to reduce the error rate of the reproduced signal.
This provides a highly reliable optical recording medium.

[Means for Solving the Problem] and [Operation] That is, the present invention provides an optical recording medium in which recording and reproduction is performed using a light beam, in which the optical recording layer is located between the light reflection layer and the light absorption layer. This is an optical recording medium characterized by having an auxiliary layer interposed therebetween.

EMBODIMENT OF THE INVENTION Hereinafter, the concrete structure of this invention is demonstrated using drawings.

FIG. 1 is a sectional view showing a typical configuration example of the present invention.

In FIG. 1, the optical recording medium of the present invention has a recording auxiliary layer 7 interposed between a light reflecting layer 6 and a light absorbing layer 8 to form an optical recording layer 2a. 2a is provided on the substrate 3 with the light absorption layer 8 facing downward, and the protective layer 4 is provided as the outermost layer.
is provided to protect the light reflecting layer 6.

In the present invention, the substrate 3 is a glass plate, a ceramic plate,
Metal plates such as aluminum plates and stainless steel plates, PVC, PMMA
, a plastic board such as a PC can be used. The substrate may be transparent or opaque, and its size is not particularly limited as long as it fulfills the function of supporting the optical recording medium, and the substrate may be omitted in some cases.

One of the features of the present invention is that the optical recording layer 2a is composed of a light reflecting layer 6, a recording auxiliary layer 7, and a light absorbing layer 8.

The optical recording layer is a so-called heat mode recording material, which absorbs the light when it is irradiated with a light beam, converts it into heat, and uses the heat to form recording pits. It is required to have a reflection of

In view of this point, the present invention is characterized in that a light reflecting layer 6, a recording auxiliary layer 7, and a light absorbing layer 8 are sequentially laminated to form an optical recording layer, as shown in FIG.

In the present invention, the light reflective layer is an important factor that determines the S/N of recorded information, and is required to have a large ratio between the reflection intensity before recording and the reflection intensity after recording.

In addition, the reflected signal from this light-reflecting layer becomes a signal that activates AT%AF, which is important for recording and reproduction of optical recording media.

Considering these points, the higher the reflectance of the light-reflecting layer, the more preferable it is, but when considering recording, an appropriate transmittance is also required, and a rational distribution of both is required.

Therefore, the reflectance of the light reflective layer is 10 to 85.
%, preferably 20 to 60%.

The light-reflecting layer is formed by vapor deposition of metals such as gold, silver, copper, electroless plating, or by coating particles of these metals dispersed in a vehicle.

The thickness of the light-reflecting layer is determined by the reflectance, which is determined by the relationship with the light-absorbing layer that makes up the optical recording layer, and the processing method, ie, whether vapor deposition, electroless plating, or dispersion medium coating is selected. The range is from several meters to several m/m, preferably from 20 A to 1.0 .mu./.cm.

In the present invention, the light absorption layer absorbs irradiated light energy and converts it into thermal energy, and the recording auxiliary layer is deformed by the heat, forming recording pits with the laminated reflective layer.

The light-absorbing layer is composed of dyes, pigments, etc. that have absorption properties at the wavelength of the recording beam during optical recording, or by dispersing these substances in a binder.

The light absorption layer is ↑e, fli, Sn, Sb,
Low melting point metals such as In and their alloys, Au, 'Ag, C
Metal particles such as u, cyanine-based, squalium-based, phthalocyanine-based, tetradehydrocholine-based, methine-based, naphthoquine-based dyes and pigments, organometallic complexes such as benzenedithiol nickel complex, black dyes such as carbon black and nigrosine, etc.・Pigments can be preferably used.

Further, the thickness of the light absorption layer is desirably from several tens of micrometers to several square meters/w+, preferably from 2,008 to 0.5 m/-.

In the present invention, the recording auxiliary layer is changed by thermal energy converted by the light absorption layer in the optical recording layer, and recording pits are formed in the light reflection layer thereon.

As the recording auxiliary layer, vinyl-based materials such as polyvinyl chloride, polyvinyl alcohol, and polyvinyl acetate, polyethylene,
Organic polymers made of resins such as olefins such as polypropylene, acrylics such as polymethyl methacrylate and polymethyl acrylate, polyesters, polyamides, polystyrenes, celluloses, polycarbonates, and ionomers, and copolymers and mixtures thereof. Molecular substances, organic carboxylic acids such as stearic acid, palmitic acid, phthalic acid, and succinic acid, and solid paraffin can be preferably used.

That is, these substances undergo thermal deformation such as melting and thermal softening at low temperatures of 400°C or lower, preferably 200°C or lower.

The thickness of the recording auxiliary layer is from 10 to 7, preferably 7
00A to 1.8m/m is desirable.

Further, the recording auxiliary layer can be formed by a conventionally known coating method such as barcode coating or roll coating.

In the present invention, the optical recording layer is provided on the substrate 3, but in that case, the optical recording layer may be set by sequentially coating or vapor depositing a light absorption layer, a recording auxiliary layer, and a light reflection layer on the substrate.
An optical recording layer may be provided via an adhesive layer such as a dry laminating agent.

Further, when the optical recording layer is coated on a thin film or the like, such as a silver salt sensitive material, the entire film can be set on the substrate via an adhesive.

In the present invention, the protective layer 4 provides mechanical, chemical, and physical environmental resistance to the optical recording layer, and covers the optical recording layer with a material transparent to recording/reproducing light.

For example, a glass plate, a ceramic plate, a plastic plate such as polymethyl methacrylate, polycarbonate, vinyl chloride, polyethylene terephthalate, polystyrene, C-39, or polymethyl pentene is provided on the optical recording layer via an adhesive layer as necessary. .

In another example, the plastic materials described above are coated directly onto the optical recording layer and cured to form a protective layer. In this case, a radiation-curable resin can also be used.

Although the protective layer is provided on the optical recording layer, it does not necessarily need to be in close contact with it, and may be provided via air or an inert gas.

The outer surface of the protective layer is treated with abrasion-resistant treatment, hardening treatment, and antifouling/staining treatment to prevent scratches and dirt from adhering during handling.
Intended for antistatic treatment and improved durability. Moisture-proofing treatment, ultraviolet-proofing treatment, and oxygen-proofing treatment (02 gas barrier treatment) can be performed as necessary.

The optical recording medium of the present invention has an optical recording layer 2 as shown in FIG.
When information is written by irradiating the laser beam l from the side a, recording pits 5 are formed in the light irradiated portion of the optical recording layer 2a. When information is written by this light irradiation,
First, the irradiated light is converted into heat in the light absorption layer, and this heat softens and melts the recording auxiliary layer 7, and deforms the light reflection layer thereon, thereby shaping the shape of the recording pit.
In other words, create a pit with a stable size without forming a rim,
It can give an excellent reproduction signal.

Furthermore, the optical recording medium of the present invention has a highly sensitive optical recording layer, which has high absorption for converting light into thermal energy, and has an appropriate reflectance for detecting signals with good contrast. , and has even more excellent durability (withstands storage for at least 10 years).

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Carbon black (manufactured by Nippon Colonhear Carbon) 3
0 parts by weight was added to 50 parts by weight of an ethanol solution containing 20% by weight of polyvinyl butyral, mixed uniformly, and the mixture was mixed to a thickness of 2.0 parts by weight. A film was formed by coating with a bar coater on a polycarbonate substrate having a thickness of 1.0 IL- to provide a light absorption layer having a film thickness of 1.0 IL-.

Next, a one-layer polyethylene vinyl acetate copolymer film was formed on the light absorption layer by heat pressing to provide a recording auxiliary layer.

Furthermore, gold was vacuum-deposited on the recording auxiliary layer to a film thickness of 50 mm.
The light reflecting layer A was provided to obtain an optical recording medium having an optical recording layer consisting of three layers.

Writing was performed on this optical recording layer using a semiconductor laser with a wavelength of 830 nm, a beam diameter of 3 μm, and a power of 3 mW on the recording surface, resulting in a read signal of 0.8 at a read power of 0.1 mW.
A contrast of 0 or more was obtained.

As a result of observing the recorded pit at this time with a scanning electron microscope, there was no formation of a rim, and the pit diameter was 3.0 ± 0.3 g.
, m, very stable recording pit sizes were obtained.

[Effects of the Invention] As explained above, in the optical recording medium of the present invention, the shape of the recording pits can be changed by forming the optical recording layer with the recording auxiliary layer interposed between the light reflection layer and the light absorption layer. This method has advantages such as being able to keep the signal constant at all times and reducing the error rate of the reproduced signal during reading.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing a typical configuration example of the optical recording medium of the present invention, Fig. 2 is a cross-sectional view showing the state of writing information, and Fig. 3 is the formation of recording pits 1 to 1 of a conventional optical recording medium. It is an explanatory diagram showing a state. l... Laser light 2 a, 2 b... Optical recording layer 3... Substrate 4... Protective layer 5
...Recording pit 6...Light reflective layer 7...
Recording auxiliary layer 8...Light absorption layer 9...Rim

Claims (1)

[Claims] An optical recording medium in which recording and reproduction are performed using a light beam, characterized in that the optical recording layer has a recording auxiliary layer interposed between a light reflection layer and a light absorption layer.