JP2009064496A - Organic thin film and optical recording medium using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new organic thin film in which a nanometer functional material dispersion structure is built and fixed in a polymer and to provide an optical recording medium which enables recording and reproduction at recording density beyond a diffraction limit of a pickup lens unattainable by a conventional optical disk by applying this organic thin film to a recording layer of the optical recording medium. <P>SOLUTION: (1) The organic thin film has a micro phase separation structure composed of a block copolymer in which two or more kinds of non-compatible polymer chains are combined, the polymer chain which forms one separation phase of this micro phase separation structure has a desorbable substitution group, and a dye with functional group combinable with this electron hole barrier at two or more places is introduced in an electron hole formed by desorption of this substitution group. (2) An optical recording medium uses the organic thin film as a recording layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a novel organic thin film in which a nanometer-sized functional material dispersion structure is constructed and fixed in a polymer, and an optical recording medium using the organic thin film as a recording layer.

It is known to use a microphase-separated structure of a block copolymer having incompatible polymer chains as a functional material. In addition, introducing a nanometer-sized functional material into a polymer and compositing it makes it possible to create a functional composite material that exhibits new functions such as electronic properties, conductive properties, optical properties, and magnetic properties. Research and development of metal-organic composite materials using metal fine particles (metal nanoclusters) as functional materials have been promoted. In addition, research and development of a composite material of a nanometer-size pigment material and a polymer that can be expected to have an infinite degree of freedom in material and functionality has been promoted (Patent Documents 1 to 3). However, it has been found that a functional composite material using a polymer has a low glass transition point and softening point, and the produced nanometer-size pattern may be destroyed.
On the other hand, in the optical memory field, CD-R, DVD-R, and DVD + R that are recordable CD-R, DVD-R, and DVD-R, which are optical recording media having a reflective layer on a substrate, have been commercialized. In such an optical recording medium, further increase in recording capacity and downsizing of recording pits are desired, and further improvement in recording density is required to realize this.
As elemental technologies for improving the recording capacity in the current system, there are recording pit miniaturization technology and image compression technology represented by MPEG2. As technology for miniaturization of recording pits, it has been studied to increase the numerical aperture NA of the optical system in order to shorten the wavelength of recording / reproducing light and improve the diffraction limit, but recording / reproducing exceeding the diffraction limit is impossible. It is.
Therefore, super-resolution technology capable of recording / reproduction exceeding the diffraction limit and optical memory systems using near-field light are attracting attention as promising means, but they have not yet been put into practical use due to the high technical hurdles. .

JP 2003-89269 A JP 2003-94825 A JP 2004-347978 A

  The present invention provides a novel organic thin film in which a nanometer-sized functional material dispersion structure is built and fixed in a polymer, and by applying this organic thin film to a recording layer of an optical recording medium, It is an object of the present invention to provide an optical recording medium that can be recorded and reproduced at a recording density exceeding the diffraction limit of a pickup lens, which cannot be realized with the above optical disk.

The above problems are solved by the following inventions 1) to 7).
1) It has a microphase separation structure formed by a block copolymer in which two or more types of polymer chains that are incompatible with each other are bonded, and the polymer chain forming one separated phase of the microphase separation structure is desorbed. A dye having a separable substituent and having a functional group capable of binding to the pore wall at two or more positions is introduced into the pore formed by the elimination of the substituent. Organic thin film.
2) The organic thin film according to 1), wherein the detachable substituent is a substituent that is eliminated by the action of an acid catalyst.
3) The organic as described in 1) or 2), wherein a heating temperature necessary for removing the detachable substituent is equal to or lower than a glass transition point (Tg) of the block copolymer. Thin film.
4) The organic thin film according to any one of 1) to 3), wherein the microphase separation structure is spherical, columnar, alternating lamellar, or a structure similar to each of the shapes.
5) An optical recording medium using the organic thin film according to any one of 1) to 4) as a recording layer.
6) The optical recording medium according to 5), wherein the microphase-separated structure has a spherical shape, a columnar shape, an alternating lamellar shape, or a cross-sectional diameter of a structure similar to each shape smaller than the spot of the recording / reproducing light. .
7) The light according to 5) or 6), which has a substrate provided with a groove, and the organic thin film according to any one of 1) to 4) is formed as a recording layer on the substrate. recoding media.

Hereinafter, the present invention will be described in detail.
As a result of various investigations, the present inventor has made use of the microphase separation phenomenon of the block copolymer, contains a component that can be removed in one phase, and introduces a dye into the pores after the component has been released. As a result, an intended organic thin film was obtained. In addition, by applying the organic thin film to the recording layer of the optical recording medium, recording / reproduction at a recording density exceeding the diffraction limit of the pickup lens can be performed.
The organic thin film of the present invention is mainly composed of a block copolymer in which two or more kinds of incompatible polymer chains are bonded to each other, and can be detached into one phase of a microphase separation structure formed by the copolymer. A dye having a functional group capable of binding to the pore wall at two or more locations (crosslinking agent having a dye moiety) into the pore after the substituent is eliminated, It is obtained by immobilizing the dye part and the block copolymer.
The feature of this organic thin film is that a nanometer order pattern can be constructed by a microphase separation structure, and a highly ordered pigment nanostructure can be formed using the pattern. Further, the dye is fixed in the structure by bonding to one phase of the block copolymer at two or more locations, so that the stability of the structure is also increased.
In the organic thin film of the present invention, since the crosslinking reaction proceeds after the film formation, the first film formation can be performed from a solution of the block copolymer. Therefore, it is possible to form a film using a simple method such as a spin coating method, a casting method, a blade coating method, etc., and when forming a nanostructure having a high regularity of the dye, it is complicated and costly such as etching. This is preferable because a technique need not be used.

As the microphase separation structure, (a) a spherical structure, (b) a columnar structure, (c) an alternating lamellar structure, or a structure similar to each of these shapes as schematically shown in FIG. 1 is preferable. The leaving substituent is preferably contained in the spherical portion, the columnar portion, one layer forming a lamella, or a similar structure portion thereof.
When a diblock copolymer consisting of two types of components is used as the block copolymer, three types of microphase-separated structures are formed: a spherical structure, a columnar structure, and an alternating lamellar structure. 1 is used, the type of structure is a structure in which three types of polymer parts constituting the block copolymer of FIG. 1 (d) are regularly arranged, FIG. 1 (e). It spreads almost infinitely, including a structure having two types of spherical parts.
In addition, in order to control these structures, you may mix other polymers (a block copolymer etc. are included) and a low molecular weight compound.
In one phase of the above microphase separation, the dye is embedded after the detached substituent, and the dye is in a state of being bonded and crosslinked with the block copolymer.

In the organic thin film of the present invention, the detachable substituent bonded to the polymer chain forming one separated phase of the microphase-separated structure can be removed by the action of an acid catalyst or the like and then removed easily. good. In addition, after the microphase separation structure is formed, heating is performed as necessary in order to advance the elimination reaction (for example, acid catalyzed reaction). At this time, in order not to destroy the microphase separation structure, the Tg of the block copolymer or lower is required. It is preferable to heat (for a short time). Thereafter, the detachable substituent is removed from the structure, whereby pores are formed in the microphase-separated block copolymer, and the dye can be efficiently introduced into the pores.
Here, the block copolymer in the present invention can be synthesized by combining two or more kinds of polymers that are incompatible with each other.

  Examples of the block copolymer used in the present invention include styrene, isoprene, α-methylstyrene, chloromethylstyrene, 2-vinylpyridine, aminostyrene, 4-vinylpyridine, methacrylates, ε-caprolactone, butadiene, and vinyl methyl ether. 1,3-cyclohexanediene, ethylene oxide, polymers obtained by polymerizing various monomers such as vinylphenol, acrylic acid, methacrylic acid and the like protected with a substituent removable by an acid catalyst, are incompatible with each other. Living polymerization method (anionic polymerization, radical polymerization) that polymerizes from the end of the polymer chain, living polymerization method (anionic polymerization) that is synthesized from the center of the chain, or a synthetic method that bonds the end of the terminal functional polymer (anionic polymerization, living radical) Synthesized by polymerization methods such as polymerization) Can. For example, by a living radical polymerization method, a block copolymer of polystyrene having a substituent that is eliminated by an acid catalyst and polymethyl methacrylate, or polystyrene and polymethacrylic acid having a substituent that is eliminated by an acid catalyst The block copolymer can be synthesized.

The acid catalyst that can be used in the present invention is not particularly limited as long as it can remove a substituent bonded to a desired polymer chain, does not inhibit pore formation, and does not break the microphase separation structure. There are no restrictions. Examples thereof include an acid compound or a compound that generates an acid compound by photoirradiation or heating (a photoacid generator or a thermal acid generator).
As the acid compound, for example, a known compound such as p-toluenesulfonic acid can be used. Moreover, as a compound which generate | occur | produces an acid compound, well-known compounds, such as sulfonium compounds, such as a triphenylsulfonium triflate, iodonium compounds, such as a diphenyl iodonium triflate, and a nitrobenzyl ester compound, can be used, for example.
The acid catalyst is appropriately selected according to the object to be applied and the manufacturing process of the organic thin film applied thereto.

After the detachable substituent is eliminated, a hydroxyl group (phenol group), a carboxyl group, and the like remain. The dye introduced into the pores only needs to have a functional group capable of binding to the pore wall at two or more locations, and the functional group preferably forms a bond easily with a hydroxyl group or a carboxyl group. Specific examples include isocyanate groups, trichloro, dichloro, monochloro silane groups, trialkoxy, dialkoxy, monoalkoxy silane groups, carboxyl groups, sulfonyl chloride groups, etc. with respect to the hydroxyl group. And a carboxyl group, a hydroxyl group, an amino group, an isocyanate group, an epoxy group, a vinyl ether group, an oxazoline group, a cyclocarbonate group, and the like.
The dye may be any one that reacts with light, and known dyes such as a cyanine dye, an azo dye, a styryl dye, and a stilbene dye can be used.

Next, an optical recording medium using the organic thin film as a recording material (recording layer) will be described.
A conventional optical recording medium includes a recording layer composed of a continuous recording material (a layer in which the recording material exists). The recording layer is irradiated with a laser beam, and some change corresponding to the shape of the laser beam ( Recording is performed by causing a recording material to generate a physical or chemical change accompanied by an optical change. Therefore, since the size of the minimum recording pit depends on the laser beam diameter determined by the oscillation wavelength of the optical system and the NA of the lens, in the conventional recording / reproducing system, the increase in density is basically the laser oscillation wavelength or lens. Has been influenced by the practical technology of NA.
Also, since the beam shape is a Gaussian distribution and there is almost no material that changes with a clear threshold for heat or light as a recording material, the size and amount of change in the outermost circumference of the pits formed Are not uniform, and there is always a variation factor in the quality of the reproduced signal, and there is a limit to obtaining high quality signal characteristics.

  In contrast, the optical recording medium of the present invention is an optical recording medium having a new structure that overcomes the problems of conventional optical recording media. That is, in the optical recording medium to which the organic thin film of the present invention is applied, the recording layer dots present in a highly ordered manner are discontinuously present through the matrix. In addition, the recording layer dots have a uniform nanometer size (10 to 500 nm). Therefore, the size of the minimum recording pit is not determined by the laser oscillation wavelength or lens NA, but is determined only by the recording layer dots to be formed, and an optical recording medium having an arbitrary recording density can be designed. In addition, since the outermost peripheral edge of the pit is also determined by the structure of the organic thin film, high quality signal characteristics without pit variations can be obtained by recording the entire recording layer dot. Is possible. The diameter of the recording layer dots is preferably smaller than the spot diameter of the recording / reproducing light because a higher-density optical recording medium can be obtained.

The configuration of the optical recording medium of the present invention and the necessary physical properties thereof will be described.
<Recording medium configuration>
The optical recording medium of the present invention has a recording layer made of the organic thin film on a substrate, but if necessary, an undercoat layer, a metal reflective layer, a protective layer, a substrate surface hard coat layer, etc. are provided as other constituent layers The configuration of the constituent layers is selected according to the purpose and required characteristics.
For example, the structural example as shown to the schematic sectional drawing of Fig.2 (a)-(d) and Fig.3 (a)-(e) is mentioned. 2A to 2D are examples in which a metal reflective layer is not provided on a substrate, and FIGS. 3A to 3E are examples in which a metal reflective layer is provided. 2 and 3, the recording layer portion is the organic thin film of the present invention.
The structure of the optical recording medium of the present invention may be a normal write-once optical disk structure (a so-called air sandwich structure in which two recording layers are provided on a substrate) and a CD-R structure (on a substrate). Further, a recording layer, a reflective layer, and a protective layer may be provided), or a DVD structure in which a CD-R structure is bonded may be used. The above configuration is an example for describing the embodiment, and other configurations may be used.

Each constituent layer of the optical recording medium of the present invention will be described.
<substrate>
The substrate must be transparent to the laser used when recording / reproducing is performed from the substrate side, but is transparent to the laser used when recording / reproducing is performed from the recording layer side (the side opposite to the substrate). There is no need.
As the substrate material, for example, plastics such as polyester resin, acrylic resin, polyamide resin, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide resin, glass, ceramic, metal, and the like can be used. Note that a guide groove for tracking, a guide pit, and a preformat such as an address signal may be formed on the surface of the substrate.
The tracking guide grooves can also be used for the arrangement of the microphase separation structure, and a schematic diagram in that case is as shown in FIG. The width of the guide groove can be adjusted so that the structures are arranged in a row, or can be adjusted so that a plurality of rows are arranged.

<Recording layer>
The recording layer causes some optical change by irradiation of laser light, and can record and reproduce information by the change, and has a micro phase separation structure as described above, and one phase is made into a hole. After that, it consists of an organic thin film embedded with a dye.
As for the optical characteristics of the dye, when reproducing using the change in absorption characteristics with respect to the recording / reproducing laser wavelength, it is preferable to control the wavelength so as to have the maximum absorption wavelength near the laser wavelength. When reproduction is performed using the change in the refractive index with respect to the laser wavelength, it is preferable to control the wavelength so that the maximum refractive index is provided in the vicinity of the laser wavelength. At that time, the wavelength may be controlled using a sensitizer or the like.

Examples of the dye include polymethine, squarylium, pyrylium, porphyrin, porphyrazine, azo, and azomethine dyes whose optical constants are changed by laser irradiation energy in a heat mode (such as thermal decomposition), and the like. Metal complex compounds, fulgides, diarylethenes, azobenzenes, spiropyrans, stilbenes, dihydropyrenes, thioindigos, bipyridines, aziridines, aromatics that change their optical constants in photon mode depending on the laser irradiation energy Photochromic materials such as rings, allylidene anilines, and xanthenes can be mentioned, and photochromic materials that can rewrite records are particularly preferable. The above dyes may be used alone or in combination of two or more. Furthermore, stabilizers (for example, transition metal complexes), ultraviolet absorbers, dispersants, flame retardants, lubricants, antistatic agents, surfactants, plasticizers, and the like may be added to the dye for the purpose of improving characteristics. Good.
The recording layer dot diameter made of the dye embedded in the pores is 5 to 500 nm, preferably 10 to 200 nm.

<Underlayer>
The undercoat layer consists of (1) improved adhesion, (2) a barrier such as water or gas, (3) improved storage stability of the recording layer, (4) improved reflectance, and (5) a substrate from a solvent. And (6) formation of guide grooves, guide pits, and preformats.
For the purpose of (1), polymer materials such as ionomer resins, polyamide resins, vinyl resins, natural resins, natural polymers, silicones, various rubber compounds such as liquid rubber, and silane coupling agents. Can be used. For the purposes of (2) or (3), in addition to the above polymeric _{materials, SiO, MgF, SiO 2,} TiO, ZnO, TiN, and inorganic compounds such as SiN, Zn, Cu, Ni, Cr, A metal or a semimetal such as Ge, Se, Au, Ag, or Al can be used. For the purpose of (4), an organic thin film having a metallic luster such as metals such as Al, Au and Ag, methine dyes and xanthene dyes can be used. For the purpose of (5) or (6), an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used.
The thickness of the undercoat layer is 0.01 to 30 μm, preferably 0.05 to 10 μm.

<Metal reflective layer>
The metal reflective layer is used when necessary according to the required reflectance.
The reflective layer is made of a metal or semi-metal that is highly corrosive and is not easily corroded, and examples thereof include Au, Ag, Cr, Ni, Al, Fe, and Sn. Among these, Au, Ag, and Al are most preferable from the viewpoint of reflectance and productivity. These metals or metalloids may be used alone or as two kinds of alloys.
The method for forming the reflective layer is not particularly limited, and examples thereof include vapor deposition and sputtering.
The thickness of the reflective layer is preferably 50 to 5000 mm, more preferably 100 to 3000 mm.

<Protective layer, hard coat layer on substrate surface>
The protective layer and the hard coat layer on the substrate surface are (1) protection from scratches, dust and dirt on the recording layer (reflection / absorption layer), (2) improvement in storage stability of the recording layer (reflection / absorption layer), (3 ) Used for the purpose of improving the reflectance. For these purposes, the materials shown in the undercoat layer can be used.
In addition, SiO, SiO ₂ or the like can be used as the inorganic material, and polymethyl acrylate, polycarbonate, epoxy resin, polystyrene, polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, natural rubber, styrene butadiene as the organic material. Thermosoftening and heat melting resins such as resins, chloroprene rubber, waxes, alkyd resins, drying oils and rosins can also be used.
The most preferable among the above materials is an ultraviolet curable resin excellent in productivity.
The film thickness of the protective layer or the substrate surface hard coat layer is 0.01 to 30 μm, preferably 0.05 to 10 μm.
As in the case of the recording layer, the undercoat layer, protective layer and substrate surface hard coat layer contain a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer, and the like. Can do.

  ADVANTAGE OF THE INVENTION According to this invention, the novel organic thin film by which the nanometer-sized functional material dispersion structure was constructed | assembled and fixed in the polymer can be provided. Also, by applying this organic thin film to the recording layer of an optical recording medium, it is possible to provide an optical recording medium that can be recorded / reproduced at a recording density exceeding the diffraction limit of the pickup lens, which cannot be realized with a conventional optical disk.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not limited by these Examples.

Example 1
A block copolymer (Tg 105 ° C.) consisting of poly (p-tert-butoxycarbonyloxystyrene) (PBOCST) and polymethyl methacrylate (PMMA) having a number average molecular weight of about 50,000 and a volume fraction of PBOCST of 16% by volume. Was synthesized by a living radical polymerization method, and the copolymer was dissolved in cyclohexanone to form a spin cast film on a quartz substrate.
Next, when this spin cast film was heat-treated at 140 ° C. for 8 hours, the phase separation structure was a spherical structure of several tens of nm or less by small-angle X-ray scattering (SAXS) measurement and transmission electron microscope (TEM) observation. (Sea-island structure) was confirmed.
Next, the spin cast film was immersed in a 1% by weight isopropyl alcohol solution of p-toluenesulfonic acid, pulled up, heated at 90 ° C. for 5 minutes, and observed with an atomic force microscope (AFM). It was confirmed that the PBOCST part was changed to poly p-hydroxystyrene (PHS), and vacancies were formed after the removal of the tert-butoxycarbonyl group.
Next, after immersing the spin cast film in a 1.0 wt% ethanol solution of a dye represented by the following [Chemical Formula 1] and TEM observation, the dye was segregated in the PHS part. confirmed. Further, when the organic thin film thus obtained was rinsed in methanol, it was confirmed that the dye did not elute and the structure was fixed.
Next, recording was performed on a laminate (that is, an optical recording medium) having an organic thin film into which the dye was introduced using 365 nm light from an ultrahigh pressure mercury lamp. The results are shown in Table 1.
Furthermore, although this laminated body was heat-processed at 100 degreeC for 2 hours, disorder of the structure was not observed.

Example 2
After immersing the spin cast film in the same manner as in Example 1 except that instead of the dye of [Chemical Formula 1], a 0.5 wt% methanol solution of the dye represented by the following [Chemical Formula 2] was used, As a result of TEM observation, it was confirmed that the dye was segregated in the PHS part. Further, when the organic thin film thus obtained was rinsed in methanol, it was confirmed that the dye did not elute and the structure was fixed.
Next, recording was performed on a laminate (that is, an optical recording medium) having an organic thin film into which the dye was introduced, using a semiconductor laser beam of 660 nm. The results are shown in Table 1.
Furthermore, although this laminated body was heat-processed at 100 degreeC for 2 hours, disorder of the structure was not observed.

Example 3
A block copolymer (Tg 105 ° C.) composed of polystyrene (PSt) having a number average molecular weight of about 70,000 and poly-tert-butyl methacrylate (PtBMA) and having a volume fraction of PtBMA of 28% by volume is synthesized by a living radical polymerization method. Then, this copolymer and triphenylsulfonium triflate were dissolved in cyclohexanone so as to be 100: 3 to form a spin cast film on the quartz substrate.
Next, when this spin cast film was heat-treated at 140 ° C. for 10 hours, the phase separation structure was confirmed to be a columnar structure of several tens of nm or less by SAXS measurement and TEM observation.
Next, after irradiating the organic thin film with light, it was heated at 100 ° C. for 3 minutes and observed with AFM. It was confirmed that a hole was formed.
Next, a 1.0 wt% ethanol solution of a dye represented by the following [Chemical Formula 3] was dropped onto the spin cast film, dried, and observed by TEM. As a result, it was confirmed that the dye was segregated in the PMAA part. It was. Moreover, when the organic thin film obtained in this way was rinsed in ethanol, the pigment | dye did not elute and it was confirmed that the structure is being fixed.
Next, recording was performed on a laminate (that is, an optical recording medium) having an organic thin film into which the dye was introduced using 365 nm light from an ultrahigh pressure mercury lamp. The results are shown in Table 1.
Furthermore, although this laminated body was heat-processed at 100 degreeC for 2 hours, disorder of the structure was not observed.

Example 4
Spin in the same manner as in Example 3 except that a 0.5 wt% methanol / pyridine (20/1) mixed solution of the dye shown in the following [Chemical 4] was used instead of the dye of [Chemical 3]. After immersing the cast film and TEM observation, it was confirmed that the dye was segregated in the PMAA part. Further, when the organic thin film thus obtained was rinsed in methanol, it was confirmed that the dye did not elute and the structure was fixed.
Next, recording was performed on a laminate (that is, an optical recording medium) having an organic thin film into which the dye was introduced using 365 nm light from an ultrahigh pressure mercury lamp. The results are shown in Table 1.
Furthermore, although this laminated body was heat-processed at 100 degreeC for 2 hours, disorder of the structure was not observed.

Example 5
After immersing the spin cast film in the same manner as in Example 3 except that instead of the dye of [Chemical Formula 3], a 1.0 wt% ethanol solution of the dye represented by the following [Chemical Formula 5] was used, As a result of TEM observation, it was confirmed that the dye was segregated in the PMAA part. Moreover, when the organic thin film obtained in this way was rinsed in ethanol, the pigment | dye did not elute and it was confirmed that the structure is being fixed.
Next, recording was performed on a laminate (that is, an optical recording medium) having an organic thin film into which the dye was introduced using 365 nm light from an ultrahigh pressure mercury lamp. The results are shown in Table 1.
Furthermore, although this laminated body was heat-processed at 100 degreeC for 2 hours, disorder of the structure was not observed.

Comparative Example 1
After immersing the spin cast film in the same manner as in Example 1 except that instead of the dye of [Chemical Formula 1], a 1.0 wt% ethanol solution of the dye represented by the following [Chemical Formula 6] was used, As a result of TEM observation, it was confirmed that the dye was segregated in the PHS portion. However, when the organic thin film thus obtained was rinsed in ethanol, it was confirmed that most of the pigment was washed away.
Next, recording was performed on a laminate (that is, an optical recording medium) having an organic thin film into which the dye was introduced using 365 nm light from an ultrahigh pressure mercury lamp. The results are shown in Table 1.
Furthermore, when this laminated body was heat-processed at 100 degreeC for 2 hours, it was confirmed that a structure changes before and after a heating.

Example 6
A block copolymer (Tg = 110 ° C.) consisting of PSt having a number average molecular weight of about 80,000, poly-2-vinylpyridine (P2VP), and PtBMA and having a volume fraction of 33:44:23 (volume%) was used. Except for this point, the spin cast film was immersed in the same manner as in Example 3 and then observed with a TEM. As a result, it was confirmed that the dye was segregated in the PMAA part. Moreover, when the organic thin film obtained in this way was rinsed in ethanol, the pigment | dye did not elute and it was confirmed that the structure is being fixed.
Next, recording was performed on a laminate (that is, an optical recording medium) having an organic thin film into which the dye was introduced using 365 nm light from an ultrahigh pressure mercury lamp. The results are shown in Table 1.
Furthermore, although this laminated body was heat-processed at 100 degreeC for 2 hours, disorder of the structure was not observed.

実施例１〜６の積層体は特定の波長の光を照射すると透過率、反射率が変化することが明らかになった。したがって、本発明の有機薄膜を基板上に設けた積層体は光記録媒体として利用可能である。また、フォトクロミック材料を用いれば、可逆記録媒体として用いることもできる。また、比較例１では色素成分が殆んど存在しなくなってしまったため、光照射しても透過率、屈折率を変化させることが出来なかった。
なお、本実験では、色素からなる記録層ドット径（数十ｎｍ）に比較して、何れも大きな面積の光源で記録したため、多数の記録層ドット及びドット間を一度に記録することになったが、該記録層ドット及びドット間と同程度のビーム径の光で記録すれば、各記録層ドット及びドット間を個別に記録することが可能である。

It became clear that the laminates of Examples 1 to 6 changed in transmittance and reflectance when irradiated with light of a specific wavelength. Therefore, a laminate in which the organic thin film of the present invention is provided on a substrate can be used as an optical recording medium. If a photochromic material is used, it can be used as a reversible recording medium. In Comparative Example 1, almost no pigment component was present, so that the transmittance and refractive index could not be changed even when irradiated with light.
In this experiment, since recording was performed with a light source having a large area compared to the recording layer dot diameter (several tens of nanometers) made of a dye, a large number of recording layer dots and dots were recorded at once. However, if recording is performed with light having the same beam diameter as that between the recording layer dots, each recording layer dot can be recorded individually.

Example 7
Except that the substrate was changed to one having a groove of 90 nm in width and 30 nm in depth formed on a Si wafer, a laminate having an organic thin film provided on the substrate was formed in the same manner as in Example 1, and the organic When the surface structure of the thin film was observed with an AFM, it was confirmed that island-like structures of microphase separation were arranged neatly in the grooves.

The schematic diagram which shows the typical micro phase-separation structure of the organic thin film of this invention. (A) a spherical structure, (b) a columnar structure, (c) an alternating lamellar structure, (d) a structure in which three types of polymer parts constituting the block copolymer are regularly arranged, (e) two types A structure having a spherical portion. (A)-(d) The schematic sectional drawing which shows the layer structure (without a metal reflective layer) of an optical recording medium. (A)-(e) The schematic sectional drawing which shows the layer structure (with a metal reflective layer) of an optical recording medium. 1 is a schematic diagram of an optical recording medium in which microphase separation structures are arranged in grooves.

Claims (7)

  It has a microphase separation structure formed by a block copolymer in which two or more types of polymer chains that are incompatible with each other are bonded, and the polymer chain forming one separated phase of the microphase separation structure can be detached An organic thin film characterized in that a dye having a functional group capable of binding to the pore wall at two or more locations is introduced into the pores formed by elimination of the substituent. .   2. The organic thin film according to claim 1, wherein the detachable substituent is a substituent that is eliminated by the action of an acid catalyst.   3. The organic thin film according to claim 1, wherein a heating temperature necessary for removing the detachable substituent is equal to or lower than a glass transition point (Tg) of the block copolymer.   The organic thin film according to any one of claims 1 to 3, wherein the microphase separation structure is spherical, columnar, alternating lamellar, or a structure similar to each of the shapes.   An optical recording medium using the organic thin film according to claim 1 as a recording layer.   6. The optical recording medium according to claim 5, wherein the microphase-separated structure has a spherical shape, a columnar shape, an alternating lamella shape, or a cross-sectional diameter similar to each shape smaller than a spot of recording / reproducing light.   7. An optical recording medium according to claim 5, further comprising: a substrate provided with a groove, wherein the organic thin film according to claim 1 is formed as a recording layer on the substrate. .

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