JPH0229948A - information recording medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information recording medium, and particularly to an optical information recording medium that records and reproduces information using light.

[Prior Art] In recent years, society has become more information-oriented, and as a means of efficiently handling a wide variety of information, information recording carriers and optical information that optically record or reproduce information, such as optical discs, optical cards, and optical tapes, have become popular. Many recording and reproducing devices have been proposed. Binarized information is stored on the information recording carrier by changes in reflectance, changes in reflected light intensity due to changes in surface shape such as the presence or absence of pits, and changes in the plane of polarization due to magneto-optic effects. There are some things that can be detected by converting them into intensity changes. The above-mentioned information recording carrier has excellent features such as a high recording density and a long lifespan because it allows non-contact recording and reproduction.

A card-shaped information recording carrier (hereinafter referred to as an optical card) is highly portable and has a large capacity compared to its size.
Recently, there has been a lot of research and development, and proposals have begun to be made.

Hereinafter, an optical card will be explained as an information recording carrier that optically records and reproduces information.

Regarding optical information recording and reproducing methods, for example, magneto-optical recording is performed in which the direction of magnetization is reversed using an energy beam, recording is performed by forming uneven pits, or recording is performed by increasing or decreasing optical reflectance. Record carriers with high and low optical reflectance, which have high SN light and are easy to manufacture, are widely used.

As a record carrier depending on the optical reflectance, for example,
Cards having a recording layer comprising silver particles dispersed in a gelatin matrix have been proposed. Information is written to the recording layer by irradiating the recording layer with a laser beam to form recording pits.

On the other hand, a so-called heat mode recording material has also been proposed in which recording is performed by irradiating the recording layer with an energy beam such as a laser beam in a spot shape to change the state of a part of the recording layer. As these recording layers, metal thin films such as tellurium and bismuth, organic thin films such as polystyrene and nitrocellulose, pigment thin films such as cyanines, and tellurium low oxide films utilizing phase transition are used. These recording materials are so-called DRAW (Direct Read After Write), which do not require any development processing after information is written, and can be read directly after writing.
;direct read after write
) media, capable of high-density recording and additional writing.

However, as shown in Figure 2, the information recording medium described above has conventionally generally used an insulating front substrate such as polycarbonate or polymethyl methacrylate, formed a recording layer thereon, and then bonded it. It is formed by bonding a protective substrate with an adhesive.

However, in the above-mentioned conventional example, when the front substrate is subjected to manufacturing processes such as transportation, heating and cooling, etc. at the heights and levels at which the information recording medium is manufactured, the surface is charged with static electricity of about 10 KV. If it is charged with static electricity, it will attract floating dust, and if left untreated, it will become defective. The size of the dust varies, and if it is left in a clean room (class 1000) or passed near by a person, up to 100gm of dust will adhere to it. However, in optical information recording media where information is recorded and reproduced using light, defects of 27 zm or more can cause errors when recording and reproducing information on the optical information recording medium, so dust and other particles due to static electricity are attracted. becomes a big problem.

In addition, polycarbonate, polymethyl methacrylate, and the like may remain as unpolymerized monomer residues or PPM autoclave, and there is a problem in that such residues deteriorate the recording layer.

[Problem to be solved by the invention] The present invention prevents electrostatic charging of an insulating substrate such as polycarbonate or polymethyl methacrylate, and provides a highly reliable information recording medium free from defects caused by adhesion of dust to the insulating substrate. The purpose is to provide

Another object of the present invention is to provide a durable information recording medium that prevents monomer residue contained in an insulating substrate from affecting the recording layer.

[Means for Solving the Problems] The information recording medium of the present invention is an optical information recording medium that records information by forming minute spots by light irradiation, and is characterized by having a transparent electrode layer on the surface of the substrate. That is.

In other words, by providing a transparent conductive layer on the side where the uneven preformat is formed on the insulating front substrate, it is possible to prevent the front substrate from being charged with static electricity, thereby ensuring reliability without defects due to dust adhering to the front substrate due to static electricity. Therefore, an information recording medium with high quality can be obtained.

Furthermore, it is possible to prevent the harmful influence of residual liquid contained in the insulating substrate on the recording layer.

Next, the present invention will be explained in detail using figures.

FIG. 1 shows one embodiment of an information recording medium according to the present invention. In Figure 1, 1 is a front substrate, 2 is a transparent electrode layer, 3 is a recording layer that can record and reproduce information using light, 4 is an adhesive layer, 5 is a protective substrate, and 6 protects the surface of the front substrate. This is a hard coat layer for

The transparent electrode used to prevent static electricity from being charged to the front substrate during the manufacturing process and to prevent monomer residue on the front substrate from affecting the recording layer is not particularly limited as long as it is a transparent and conductive film, but it may be a resistor. In terms of value and transmittance, ITO film (In2
O3+ 5n02 film), Z, O, film, etc. are preferred.

Vacuum deposition is the method used to form this transparent electrode. When forming on a resin substrate such as polycarbonate or polymethyl methacrylate, it is preferable to keep the substrate heating temperature below 80°C. Reactive sputtering methods are preferred. The film thickness of this pole is lOOλ ~ 1000 people, especially 300 ~ 600 people
People are preferred. In other words, if the thickness is 1000 Å or more, recording/
The transmittance of the reproduction light decreases, and if the thickness is less than 100 Å, the covering of the monomer residue on the front substrate becomes incomplete.

In the present invention, the material used for the front substrate of the information recording medium is preferably one that has few inconveniences in optical recording and reproduction, and is preferably a thermoplastic material that has good moldability for forming track grooves. For example, acrylic resin, polyester resin, polycarbonate resin, vinyl resin, polyimide resin, polyacetal resin, polyolefin resin, polyamide resin, cellulose derivative, etc. can be used.

As the protective substrate, any material that can be used as a substrate for ordinary information recording media can be used. Specifically, polyvinyl chloride, vinyl chloride/vinyl acetate copolymer, polyvinylidene chloride, polymethacrylic acid Acrylic polymers such as methyl, polystyrene, polyvinyl butyral, acetyl cellulose, styrene/butadiene copolymers, polyethylene, polypropylene, polycarbonate, etc. are used. Depending on the case, iron, stainless steel,
Metal sheets of aluminum, tin, copper, zinc, etc., synthetic paper, etc. may also be used. Furthermore, a laminate of the materials mentioned above may also be used.

Further, the protective substrate may be subjected to pretreatment to improve adhesion, such as corona discharge treatment, plasma treatment, and primer treatment, if necessary.

For the optical recording layer 22, if the wavelength of the energy beam for reproduction is 650 nm or more, especially 700 to 900 nm, the difference between the reflectance at a certain pit in the recorded area and that in the unrecorded area is large. preferable. Further, it is preferable that the energy required to cause a change in reflectance by irradiation with the energy beam for recording is small.

Furthermore, it is preferable that the reflectance of the recorded and unrecorded areas does not change due to the reproduction energy beam. for example,
Oxides such as Te, Sb, Mo, Ge, V, Sn, etc., compounds such as Te-5n, Te0x-Ge, etc. undergo a phase transition when irradiated with an energy beam, resulting in a change in reflectance. Also, Te CH4+ Te-C32.

Te-styrene, 5n-3O□, GeS-5n,
Composites of metals such as SnS-3 and organic compounds or inorganic sulfides, 5in2/Ti/5in2/A
Multilayer films such as fL can also be used. Further, it is also possible to use a thermoplastic resin such as nitrocellulose, polystyrene, or polyethylene in which metal particles such as silver are dispersed, or a thermoplastic resin in which metal particles are aggregated on the surface. In addition, chalcogen or colored MO
O:l-Cu, MOO3-Sn-Cu, etc. can also be used, and depending on the case, a multilayer body of a bubble-forming organic thin film and a metal thin film can also be used. In addition, organic thin films whose optical properties can be changed by energy beams can also be used.
For example, anthraquinone derivatives, especially those having an indathrene skeleton, dioxazine compounds and their derivatives, triphuedithiazine compounds, phenanthrene derivatives, cyanine compounds, merocyanine compounds, pyrylium compounds, xanthine compounds, triphenylmethane compounds,
Colorants such as croconium pigments and croconium pigments can be cited, and these are preferable for the present invention because they can be manufactured continuously by solution coating.

[Example] Next, the present invention will be explained in more detail by showing examples.

Example 1 A front substrate has a width of 54 mm, a length of 85.6 mm, and a thickness of 0.
A guide groove having a track groove width of 37 zm, a track pitch logm, and a depth of 0.15 JLm was formed using a 3 mm polymethyl methacrylate film by hot pressing.

An ITO film (In, 03+ SnO, film) was formed on this substrate by sputtering to a thickness of 600 nm. The resistance value of this ITO film is 4Ω/cI
The transmittance of 833-nm semiconductor laser light was 94%.

Then, 1,1,5,5-tetrakis-
An optical recording layer made of (p-diethylaminophenyl)-2,4-pentadienium perchlorate and having a thickness of 1500 nm was formed. Using the same material as the protective substrate with a thickness of 0.3 mm and an ethylene-vinyl acetate adhesive as the adhesive, the bonding temperature was 100''C with a roll laminator.
Further, a hard coat layer made of an acrylic modified resin was formed on the recording/reproducing light incident surface of the front substrate to obtain an information recording medium of the present invention.

The information recording medium manufactured in this way was mounted on an optical information recording/reproducing device, and a semiconductor laser with a wavelength of 830 nm was used to record from the front substrate side at a recording power of 4.W and a recording frequency of 100K.
100 using a laser with a Hz spot size of 3gmΦ
Write information to the track, playback power 0.4. ,,W
It was played with. At this time, the charged voltage of the front substrate was measured, and the rarate was 3.5×10'', and no dust was observed due to static electricity.

Comparative Example 1 An information recording medium was obtained in the same manner as in Example 1 except that the ITO film was not provided. When the obtained information recording medium was subjected to the same recording/reproducing test as in Example 1, the charging voltage of the front substrate was IKV, dust was observed to be attracted by static electricity, and the byte error rate was a, 5xto-3. .

[Effects of the Invention] As explained above, an information recording medium in which a transparent electrode is formed on the surface of the front substrate on which the concavo-convex preformat is formed can prevent defects caused by the attraction of dust due to static electricity during the manufacturing process. Further, it is also possible to prevent dust from being attracted to the surface of the information recording medium.

Furthermore, since the recording layer material and the front substrate do not come into contact with each other, substances such as unreacted slag in the front substrate do not react with the material, so that the properties of the recording layer material are not deteriorated.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an information recording medium according to the present invention. FIG. 2 is a schematic cross-sectional view of a conventional optical recording medium. l...Top substrate 2...Transparent electrode layer 3...Recording layer 4...Adhesive layer 5...Protective substrate

Claims (1)

[Scope of Claims] An optical information recording medium that records information by forming minute spots through light irradiation, the information recording medium having a transparent electrode layer on the surface of the substrate.