KR100247799B1 - Optical recording medium - Google Patents

Abstract

According to the present invention, a substrate, a reflective layer, a charge generating layer, a charge transport layer, and an electrically viscous fluid material are sequentially stacked, and a spacer is formed on the top of the electrically viscous fluid to form an air layer, and a protective layer is stacked on the spacer forming the air layer. An organic optical recording medium, which emits electric charges in a charge generating layer by irradiating laser light and transports the generated charges in the charge transporting layer to change the state of the electric viscous fluid from the fluid state to the gel state to perform optical recording. It relates to a recording medium, which is erased by a discharge method in the case of erasing the recording medium, and is reproduced by irradiating with a laser intensity lower than the energy at the time of recording and reading and reproducing the difference in the amount of reflection or transmission. High density and stable erasing characteristics.

Description

Optical recording media

1 is a cross-sectional view of the light incident state of the present invention,

2 is a cross-sectional view of the recording state according to FIG. 1;

3 is a cross-sectional view of the recorded state of the present invention.

<Explanation of symbols for main parts of drawing>

1 substrate 2 reflective layer

3; Charge Generation Layer 4: Charge Transport Layer

5: electric viscous fluid 6: spacer

7: air layer 8: protective layer

The present invention relates to an organic optical recording medium capable of recording, reproducing, and erasing by using a laser, and can be used as various information recording media or image recording media as a high density and large capacity information recording material.

The explosive increase of various kinds of information due to the high degree of informatization of society in general necessitates high density, large capacity and high speed of storage media.

Recently, the most practical storage method is a magnetic method in which information is recorded according to the magnetization direction of the magnetic medium magnetic material. Examples of its use include video tapes, audio tapes and floppy disks.

However, the increase in the amount of information due to social development requires a large amount of recording media, resulting in the emergence of magneto-optical recording media. Unlike magnetic materials used in magnetic recording media, the magnetization direction is perpendicular to the surface of the recording film, and the coercivity to maintain the magnetization direction is 5 to 10 times higher than that of the magnetic media. it's difficult. Therefore, in order to change the magnetic direction, information can be recorded in accordance with the magnetic direction by changing the magnetic direction to an external magnetic field in a state in which light is focused to 1 μm or less using a laser and heated above the Curie temperature. When recording in this manner, the information recording unit can be made smaller than 1 μm, which can have a recording density of 10 to 1000 times that of the magnetic memory method, and the recording preservation is easy and the life is long by using the non-contact memory reproducing method.

However, this method uses a heavy metal magnetic material and requires a vacuum deposition or sputtering device in the manufacturing process, there are a lot of difficulties in manufacturing. Attempts have been made to use organic optical recording materials to address these shortcomings.

The organic optical recording material can be classified into a write once read many (WORM) type that can only be read after writing once and a rewritable (RW) type that can be erased after writing, depending on whether or not it can be erased.

WORM type, as mentioned in Japanese Unexamined Patent Publication No. 57-46362, 58-197088, 59-5096, 63-179792, etc., after coating a pigment that can absorb a laser on the reflective layer mixed with a polymer resin It is made by coating a protective layer on it. At the time of recording, when the laser is focused on the recording layer within 1 μm, heat is generated by the dye absorbing the laser, and the polymer resin is decomposed to form a pit, thereby enabling recording. In recording and reproducing, the information is read by the difference in reflectance between the portion with and without the pit. In the WORM type, since the recorded portion becomes the decomposition form of the polymer, it is impossible to rewrite after erasing the recording.

The RW (Rewritable) type is a thermal method using light as heat and a photon method using photons of light. In the case of the thermal method, the recording light is irradiated onto the recording layer to locally melt, evaporate, thermally deform or heat transfer, and to record and reproduce by optical changes occurring at that time. As the material of the optical recording medium using this method, an optical magnetic recording medium using the Faraday effect and the Carr effect using TbFe, CdFe, TbFeCo, etc., TeOx, Te-Ge, Te-Ge-Sb, Te Inorganic systems using -Ge-Sb-Tl and the like have been actively studied. However, the optical recording medium not only uses materials harmful to the human body, but also deposits a metal compound by the spattering method, so that the stability of the medium is low and the manufacturing process is difficult. In the organic system, a method using a phase shift of a liquid crystal (JP-A-58-199345, 63-74135) and a method using a phase separation of a blend of a polymer have been proposed. However, it has not been put to practical use for reasons such as recording time. Such a thermal recording method has a problem in that the system at the time of erasing is complicated in addition to the problem of stability of the material by heat. Correspondingly, the photon recording method of the photon method has attracted attention as a high-sensitivity and high speed optical recording medium, such as spiropyran (Japanese Patent Laid-Open No. 61-17037), Fulgid, and Indigo 61-128244) has been proposed as an optical recording medium. However, while the photon method has the above excellent characteristics, the light resistance due to light is bad, so that the stability of color development and repeatability are not good.

In general, in the case of the photochromic compound, when the recording light is ultraviolet light, since the erasure light is visible light, stable preservation of the recording is very difficult. Due to these reasons, the development has not progressed rapidly while having the advantages of high density and high speed. In view of the above, a compatible organic recording medium needs to be supplemented in terms of stability, sensitivity, and complexity of the erasing system, and a new medium that takes this aspect into consideration in order to switch to a new optical recording method is required. Therefore, the present invention aims to construct an optical recording medium having excellent sensitivity and stability by using the principle of transfer of charge due to light and avoiding the optical recording method using conventional heat and photons by light.

To this end, the present invention relates to a slow exchangeable organic optical recording medium, and to perform optical recording using a procedure different from the conventional optical recording, and the stability, which has been presented as a problem in various conventional optical recording media described above. It provides a new recording medium with advantages in terms of recording and erasing time, manufacturing process, and sensitivity. Especially, it is a recording medium with excellent recording sensitivity and stability among recording characteristics. It is characterized by providing an excellent optical recording medium by increasing the number of iterations.

That is, in the present invention, a substrate, a reflective layer, a charge generating layer, a charge transport layer, and an electrically viscous fluid material are sequentially stacked, and a spacer is formed on the top of the electrically viscous fluid to form an air layer, and a protective layer is formed on the top of the spacer forming the air layer. A stacked organic optical recording medium comprising: irradiating laser light to generate charge in the charge generating layer, and transporting the generated charge in the charge transport layer to change the state of the electric viscous fluid from the fluid state to the gel state to perform optical recording. It relates to an optical recording medium.

Hereinafter, the present invention will be described with reference to the drawings.

As shown in FIG. 1, the optical recording medium of the present invention includes a substrate 1, a reflective layer 2, a charge generating layer 3, a charge transport layer 4, an electrically viscous fluid 5, a spacer 6, It consists of an air layer 7 and a protective layer 8, and according to this configuration, the laser beam is absorbed in the laser wavelength band irradiated by the charge generating material of the charge generating layer 3 by irradiating the surface to be recorded by the focused laser light. Thereby generating charges on the surface of the recording layer and transporting the generated charges from the charge transport layer 4 to the surface of the electrically viscous fluid 5, thereby generating an electric field effect on the surface formed at the light irradiation site (FIG. 2). . Due to the influence of the electric charges, the electric charges are present in the light irradiation part, and thus a gel state different from the fluid state of the recording layer is formed. This characteristic is used for recording. When reading the data, the intensity of reflection or transmission of the recorded state is measured by investigating the intensity of laser that is weaker than the time of recording, that is, the energy of the laser generating energy in the charge generating layer. Reading is possible. In the erasing, the charges on the recording surface are discharged to remove the charges formed on the surface, which makes the erasing much simpler than in the conventional organic light recording erasing system (FIG. 3). In the present invention, the charge generating layer 3 and the charge transport layer 4 may use an inorganic material, and in this case, only one layer may be used. This is because inorganic materials generally have characteristics of charge generation and transport, and inorganic materials that can be used at this time include selenium cadmium sulfides, zinc oxides, and amorphous silicon (Amorphous silicon). At least one of amorphous silicon) can be used.

At this time, the thickness of the inorganic material layer having the functions of the charge generating layer and the charge transport layer is preferably 0.1 ~ 10μm.

On the other hand, when these layers are made of an organic material, the charge generating layer 3 is coated by dispersing the charge generating material in the resin, and the resin used is polycarbonate or poly methylmethacrylate. Is common and the charge generating material dispersed in the resin is 1 to 10wt% with respect to the polymer resin. In this case, the glass material as a charge generating material is polyazo, perylene tetracarboxy diimides, polycyclic quinone, phthalocyanines, and squariliums. ), And at least one or more types of thiapyryliums may be dispersed, and the charge transport layer 4 may be used as a charge transport material in the resin as a hydrazone, pyrazoline, or stilbenz. (stylbenes), triphenylmethane (try-phenylmethane), heterocycle (heterocycles), conjugated arylamides (conjugated arylamides) and at least one or more coatings by dispersing 1-10wt% to the polymer resin Can be used. At this time, the thickness of the charge generation layer 3 is appropriately 0.1μm ~ 0.3μm, the charge transport layer 4 is suitable 10-30μm. The selection of the materials for the charge generating layer 3 and the charge transport layer 4 should be appropriately selected according to the wavelength band of the laser to be recorded. The electrically viscous fluid 5 is generally composed of dispersed particles, a dispersion medium, and an additive. By proper selection and blending of these components, the fluid, which is a fluid in a normal state, changes to a gel state in a state over a certain electric field.

As the material used for the electric viscous fluid 5 in the present invention, the dispersed particles are aluminum dihydrogen, tripoly phosphate, calcium titanate, carbon (graphite), carboxymethyl dextran, cellulose, diatomite, Kaolinite, Montmorillonite, Vermiculite, Polygorskite, Copper Phthalocyanine, Zeratin, Gypsum, Ferric Oxide, Tertiary Iron Oxide, Lime, Pentaerythritol (Pentaerythritol), phthalocyanine, Piezo ceramic power, silica, sodium carboxymethyl cellulose, sodium carboxymethyl dextran, Srarch, sulfopropyl dextran, tin 2 oxide, titanium dioxide, As the dispersion medium, polychlorinated bisphenol, poly (tri-fluorovinyl chloride), o-dichlorobenzene, p-chloro Ruene, xylene and mixtures thereof and spindle oil, water, naphthenic oil, transformer oil, olive oil, mineral oil, kerasine, petrolatum, hydrocarbon, lubricants, silicone oil, paraffin grease, di-n-butylphthalate, di -n-octylphthalate, di-n-decylphthalate, di-isodecylphthalate, tri-2-ethylhexyl trimellitate, tri-isodecyltrimethylate, tri-cresyl phosphate, dibutyl sebacate, di-2 -Ethylhexyl ediate, poly (p-phenylmethyl siloxane), and the like may not be added as a dispersing accelerator, but when added, water, aqueous ammonium solution, surfactant, electrolyte, diethylamine, glycerol, ester, fatty acid , Triethanol amine, or the like can be used individually or in mixtures. The constituent content of the electrically viscous fluid is preferably 2 to 50 wt% of the dispersed particles and 0 to 30 wt% of the additive with respect to the dispersion medium.

In the present invention, the electrically viscous fluid 5 is sealed and spacers 6 are provided on both sides of the electrically viscous fluid to hold the air layer 7 and finally form the protective layer 8. Preferred spacer 6 materials include glass beads, and the protective layer 8 is preferably the same material as the substrate 1, preferably polycarbonate.

In the present invention, the reflective layer 2 is preferably formed by depositing aluminum at 200 to 500 mW as a metal component.

In the present invention, in order to maintain a stable state of charge, if the photomask is placed on the electrically viscous fluid 5, a more stable recording state can be maintained, and at this time, it should be divided by the focal size of the laser to be recorded, and about 1 to 3 μm It is suitable, and the recording sensitivity and stability are remarkably improved. An Example is given to the following and this invention is further demonstrated to it.

Example 1

After depositing 300 알루미늄 of aluminum on the polycarbonate substrate 1 with the reflective layer 2, the charge generating material (phthalocyanine-based organic material) was dissolved in a solvent with a polycarbonate resin at a weight ratio of 50:50, and spin-coated at 0.2 μm. Stored at 10 ℃ for 10 hours to dry the solvent to complete the charge generating layer (3). As the charge generating substance used, a substance of the trade name Fogen (manufactured by ICI Corp.) was used as the phthalocyanine compound. The charge transport material was again dissolved on the charge generating layer 3 in a weight ratio of 50:50 with polycarbonate, and then dried under the same conditions to complete the charge transport layer 4. As the charge transport material used, a brand name Protranti (manufactured by ICI; Hydzone Zone) was used. On top of this, an electrically viscous fluid (5) in which silica was dissolved in silicone oil was laminated. The electrically viscous fluid (5) was used by adding 5 wt% of silica as a dispersed particle to a dispersion medium silicone oil, and a spacer made of glass beads (6). ) Is formed on the side, and then attached thereon using a polycarbonate substrate as the protective layer 8. A 10 mW laser (λ = 780 nm) was modulated at 0.1 μsec, 600 rpm, and 300 KHz on the finished medium. In this case, it was confirmed that the recording site showed the gel state by the electrostatic charge. After recording, the laser was irradiated with 1.0mW (780nm) under the same condition, and the C / N ratio was measured after reading the recording. . Therefore, the recording characteristics were superior to other general erasable organic optical recording materials. In addition, after the optical recording medium was left at 40 ° C. and 80% relative humidity for 10 days, the optical recording medium was almost 70 dB, indicating that the organic optical recording medium was stable even in the environment. And erase characteristics.

Example 2

An optical recording medium was prepared in the same manner as in Example 1, but instead of the organic charge generating layer 3 and the charge transport layer 4, inorganic selenium was deposited to a thickness of 0.5 μm, whereby recording and erasing were performed in the same manner. The same result was obtained.

As described above, the optical recording medium of the present invention enables high density of information, has excellent recording and erasing characteristics at a high speed, and provides a stable optical recording medium.

Claims (11)

On the substrate, a reflective layer, a charge generating layer, a charge transport layer, and an electrical viscous fluid are sequentially stacked, forming a spacer on top of the viscous fluid to form an air layer, and a protective layer on top of the spacer forming the air layer. Optical recording is performed by generating an electric charge in the charge generating layer and transporting the generated charge in the charge transporting layer to change the state of the electric viscous fluid from the fluid state to the gel state. The method of claim 1, wherein the charge generating layer is a charge generating material by dispersing at least one of polyazo, phenylene tetra carboxyimide, polycyclic quinone, phthalocyanine, squiarlium-based, and cyapryllium-based resin Optical recording medium, characterized in that configured. The method of claim 1, wherein the charge transport layer is composed of a charge transport material by dispersing at least one or more of the hydrazone, parazoline, stilbenz, triphenyl methane, heterocycle, and kenjugate attylamide in the resin Optical recording medium, characterized in that. The optical recording medium according to claim 2 or 3, wherein the resin is polycarbonate or poly methyl methacrylate. The optical recording medium according to claim 1, wherein the electrically viscous fluid is formed by adding 2-50 wt% of dispersed particles and 0-30 wt% of an additive gen to the dispersion medium. According to claim 1 or 5, wherein the dispersed particles of the electro-viscous fluid is aluminum dihydrogen, tripoly phosphate, calcium titanate, carbon (graphite), carboxymethyl dextran, cellulose, diatomite, kaolin Knight, Montmorillonite, Vermiculite, Polygorskite, Copper Phthalocyanine, Zeratin, Gypsum, Ferric Oxide, Ferric Trioxide, Lime, Pentaerythritol At least one of pentaerythritol, phthalocyanine, Piezo ceramic power, silica, sodium carboxymethyl cellulose, sodium carboxymethyl dextran, srarch, sulfopropyl dextran, tin 2 oxide, titanium dioxide Optical recording medium, characterized in that the above use. 6. The dispersion medium of claim 1 or 5, wherein the dispersion medium of the viscous fluid is polychlorinated bisphenol, poly (tri-fluorovinyl chloride), o-dichlorobenzene, p-chlorotoluene, xylene and Mixtures of these, spindle oil, water, naphthenic oil, transformer oil, olive oil, mineral oil, kerasin, petrolatum, hydrocarbon, lubricants, silicone oil, paraffin grease, di-n-butylphthalate, di-n-octyl Phthalate, di-n-decylphthalate, di-isodecylphthalate, tri-2-ethylhexyl trimellitate, tri-isodecyl trimethyltate, tri-xylene phosphate, dibutyl sebacate, di-2-ethylhexyl adipate And at least one of poly (p-phenylmethyl siloxane). The method of claim 1 or 5, wherein the additive of the electro-viscous fluid is characterized in that at least one of water, aqueous ammonium solution, surfactant, electrolyte, diethylamine, glycerol, ester, fatty acid, triethanol amine is used. Optical recording medium. The optical recording medium according to claim 1, wherein the viscous fluid is formed by thinly depositing a photomask thereon. The optical recording medium according to claim 1, wherein the charge generating layer and the charge transporting layer are composed of one inorganic deposition layer. The optical recording medium according to claim 10, wherein the inorganic material constituting the inorganic deposition layer is at least one of selenium, cadmium sulfide, zinc oxide, and amorphous silicon materials.