Optical recording medium, information recording method, and information reading method

Abstract

An optical recording medium (100) according to one aspect of the present disclosure comprises: a recording layer (10); and a dielectric layer (20) that is positioned on the recording layer (10) and contains a porous organic structure. The information recording method according to one aspect of the present disclosure includes: preparing a light source that emits light having a wavelength of 390 nm or more and 420 nm or less; and a recording layer (10) that focuses the light from the light source and irradiates the light onto the optical recording medium (100).

Description

Technical Field

[0001] The present disclosure relates to an optical recording medium, a method for recording information, and a method for reading information. Background Art

[0002] As a technology for increasing the recording capacity of an optical information recording medium, three-dimensional recording of information in a multilayer body is known. In the field of three-dimensional recording, in order to increase the recording density, a finer light focusing point must be achieved. From the perspective of the diffraction limit of the focused laser, in order to achieve a finer light focusing point, a laser with a short wavelength is used. As such a laser, a laser with a central wavelength of 405 nm, which is the specification of a Blu-ray (registered trademark) disc, can be cited. In this way, an optical recording medium using a laser with a central wavelength of 405 nm is known.

[0003] The optical recording medium includes, for example, a recording layer and a dielectric layer on the recording layer (for example, Patent Document 1). In Patent Document 1, an optical recording medium including a recording layer formed of an optical information recording material is capable of holographic recording.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6448042 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the prior art, there is room for improvement in the recording sensitivity of optical recording media.

[0009] Means for solving problems

[0010] An optical recording medium in one aspect of the present disclosure includes: a recording layer; and a dielectric layer located on the recording layer and including a porous organic structure.

[0011] Effects of the Invention

[0012] The present disclosure provides an optical recording medium having improved recording sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a cross-sectional view showing a schematic structure of an optical recording medium according to one embodiment of the present disclosure.

[0014] Figure 2A This is a flowchart related to a method of recording information using an optical recording medium according to one embodiment of the present disclosure.

[0015] Figure 2BThis is a flowchart related to a method of reading information using an optical recording medium according to one embodiment of the present disclosure.

[0016] Figure 3 The solid of the intrinsically microporous polymer used in the examples is shown in 13 C-NMR spectrum. DETAILED DESCRIPTION

[0017] (Insights that form the basis of this disclosure)

[0018] As low-cost and high-capacity optical recording medium, multilayer optical recording medium is particularly concerned.Multilayer optical recording medium is, for example, a recording device that is alternately stacked with a recording layer comprising a pigment and a dielectric layer comprising a polymer. The pigment of the recording layer, for example, has nonlinear optical properties. The polymer of the dielectric layer is typically a nonporous polymer. As the material of the recording layer, when using a pigment with nonlinear optical properties, the physical property space of the recording layer can be selectively changed, thus, the recording memory can be made large-capacity.

[0019] In an optical recording medium, the recording layer includes, for example, a resin and a pigment that generates heat by absorbing light. In the recording layer, the pigment absorbs the recording light, thereby generating heat. The generated heat is transferred to the resin, and the shape of the resin changes, thereby forming a recording mark. Based on the light irradiation energy required for the formation of the recording mark, the recording sensitivity of the optical recording medium can be evaluated. Furthermore, the recording sensitivity can also be evaluated based on the pulse amplitude related to the light irradiation energy.

[0020] If the optical recording medium does not have a dielectric layer and the recording layer is in contact with air, the heat generated in the recording layer is effectively utilized in the recording layer due to the heat-insulating effect of the air. In this case, the recording sensitivity is good because the deformation of the resin occurs easily. However, if a non-porous dielectric layer is stacked on the recording layer, the heat-insulating effect generated by the air is not obtained, and the recording layer is easy to dissipate heat. In this way, the reduction of the recording sensitivity becomes a problem for the optical recording medium with a stacked structure.

[0021] An optical recording medium having a stacked structure is produced, for example, by alternately stacking a recording layer containing a nonlinear light absorbing pigment and a non-porous dielectric layer. However, in this method, as the dielectric layers are stacked, the thermal properties and strength of the recording layer sometimes change, and the recording sensitivity at the excitation wavelength is greatly reduced.

[0022] As described above, as a method for realizing a low-cost and large-capacity optical recording medium, it is considered to introduce a dielectric layer having high light transmittance to the recording and reproducing wavelength on a recording layer containing a nonlinear light absorbing pigment, and to alternately stack these layers. However, in the past, by stacking dielectric layers, there was a tendency that the thermal insulation and mechanical strength of the recording layer would change under recording and reproducing conditions, and the recording sensitivity would be reduced.

[0023] As a result of the research conducted by the present inventors, it was newly discovered that a dielectric layer including a porous organic structure suppresses the decrease in recording sensitivity. In particular, the dielectric layer is suitable for suppressing the decrease in recording sensitivity when light having a wavelength in a short wavelength range is used. In this specification, the short wavelength range means a wavelength range including 405 nm, for example, a wavelength range of 390 nm or more and 420 nm or less. In particular, the dielectric layer including a porous organic structure is suitable for suppressing the decrease in recording sensitivity when light having a wavelength near 405 nm is used.

[0024] (Overview of one aspect of the present disclosure)

[0025] A first aspect of the present disclosure relates to an optical recording medium including: a recording layer; and a dielectric layer located on the recording layer and including a porous organic structure.

[0026] According to the first embodiment, the dielectric layer has pores due to the porous organic structure. Due to the heat insulation effect of the air in the pores, it is possible to suppress the heat generated in the recording layer during the recording operation from being released from the recording layer. Since the heat generated in the recording layer is effectively used in the recording layer, the recording sensitivity of the optical recording medium is improved.

[0027] In a second aspect of the present disclosure, for example, according to the optical recording medium of the first aspect, the porous organic structure may have a thickness of 50 m 2 / g or more specific surface area.

[0028] In a third aspect of the present disclosure, for example, according to the optical recording medium pertaining to the first or second aspect, the porous organic structure may have an average pore diameter of 0.3 nm or more and 50 nm or less.

[0029] In a fourth aspect of the present disclosure, for example, according to the optical recording medium pertaining to any one of the first to third aspects, the porous organic structure may have an average pore diameter of 0.3 nm or more and 3 nm or less.

[0030] With the optical recording media according to the second to fourth aspects, the recording sensitivity is improved.

[0031] In a fifth aspect of the present disclosure, for example, in the optical recording medium according to any one of the first to fourth aspects, the porous organic structure may be an intrinsically microporous polymer.

[0032] The inherent microporous polymer described in the fifth embodiment has, for example, a twisted rigid main chain skeleton, which suppresses entanglement between the main chain skeletons. Therefore, the dielectric layer containing the inherent microporous polymer has the following tendency: it has nanometer-sized pores. According to the nanometer-sized pore structure, there is a tendency to suppress the light scattering of the recording and reproducing light. This pore structure is also suitable for improving the recording sensitivity of the optical recording medium because it exerts the heat insulation effect generated by the air in the pores.

[0033] In a sixth aspect of the present disclosure, for example, according to the optical recording medium of the fifth aspect, the intrinsically microporous polymer may include a structural unit represented by the following formula (1).

[0034] [Chemical formula number 1]

[0035]

[0036] In the formula (1), R1 to R 18 They independently contain at least one atom selected from H, B, C, N, O, F, Si, P, S, Cl, Br and I, and X is independently F, Cl, Br or I.

[0037] In a seventh aspect of the present disclosure, for example, in the optical recording medium according to the fifth or sixth aspect, the intrinsically microporous polymer may include a structural unit represented by the following formula (2).

[0038] [Chemical formula number 2]

[0039]

[0040] In the inherent microporous polymer described in the sixth to seventh schemes, the π conjugation system of the main chain skeleton is short. As far as the inherent microporous polymer is concerned, there is a tendency to suppress the absorption of recording and reproducing light. Furthermore, in the inherent microporous polymer, cations are generated by introducing substituents such as hydrogen atoms or alkyl groups into nitrogen atoms. In other words, the inherent microporous polymer has a cationic main chain skeleton. The inherent microporous polymer is hydrophilic and soluble in highly polar solvents. In this case, for the hydrophobic recording layer, a coating liquid containing an inherent microporous polymer can be applied to make a dielectric layer.

[0041] In an eighth aspect of the present disclosure, for example, according to the optical recording medium pertaining to any one of the first to seventh aspects, the recording layer may contain an organic compound having nonlinear optical characteristics.

[0042] In a ninth aspect of the present disclosure, for example, according to the optical recording medium pertaining to the eighth aspect, the nonlinear optical characteristic may be a two-photon absorption characteristic.

[0043] According to the eighth to ninth aspects, the recording capacity of the optical recording medium can be easily increased.

[0044] The information recording method involved in the tenth scheme of the present disclosure includes: preparing a light source that emits light with a wavelength of not less than 390nm and not more than 420nm; and focusing the light from the light source and irradiating the recording layer in the optical recording medium involved in any one of the first to ninth schemes.

[0045] According to the tenth aspect, information can be recorded on the optical recording medium at a high recording density.

[0046] The eleventh scheme of the present disclosure involves a method for reading information, for example, a method for reading information recorded using the recording method involved in the tenth scheme, and the reading method includes: irradiating light to the recording layer in the optical recording medium to thereby measure the optical properties of the recording layer; and reading information from the recording layer.

[0047] In a twelfth aspect of the present disclosure, for example, according to the reading method pertaining to the eleventh aspect, the optical characteristic may be the intensity of light reflected by the recording layer.

[0048] According to the eleventh and twelfth aspects, information can be easily read from the optical recording medium.

[0049] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments.

[0050] (Implementation Method)

[0051] Figure 1 1 is a cross-sectional view showing a schematic structure of an optical recording medium 100 according to one embodiment of the present disclosure. Figure 1 As shown, the optical recording medium 100 includes a recording layer 10 and a dielectric layer 20. The dielectric layer 20 is located on the recording layer 10, for example, directly in contact with the recording layer 10. The optical recording medium 100 has a stacked structure of the recording layer 10 and the dielectric layer 20. The dielectric layer 20 includes a porous organic structure.

[0052] The optical recording medium 100 may include a plurality of recording layers 10. The plurality of recording layers 10 are arranged, for example, in the thickness direction of the optical recording medium 100. In the optical recording medium 100, the number of recording layers 10 is not particularly limited, and is, for example, 2 or more and 1000 or less. The optical recording medium 100 including the plurality of recording layers 10 functions as a three-dimensional optical storage. A specific example of the optical recording medium 100 is a three-dimensional optical disc.

[0053] The dielectric layer 20 may be, for example, an intermediate layer located between two recording layers 10. The optical recording medium 100 may include a plurality of dielectric layers 20. In the optical recording medium 100, the plurality of recording layers 10 and the plurality of dielectric layers 20 may be arranged alternately. In other words, the plurality of recording layers 10 and the plurality of dielectric layers 20 may be alternately stacked. As an example, the plurality of recording layers 10 are each arranged between two dielectric layers 20 and are directly in contact with each of the two dielectric layers 20. In the optical recording medium 100, the number of dielectric layers 20 is not particularly limited, and is, for example, 3 or more and 1001 or less.

[0054] [Dielectric layer]

[0055] As described above, the dielectric layer 20 includes a porous organic structure. In this specification, a porous organic structure means an organic compound having a porous structure. For example, a film having a porous structure can be easily formed by a coating method according to the porous organic structure. The so-called coating method is a method of preparing a film by coating a coating liquid containing a porous organic structure and drying the obtained coating film. The dielectric layer 20, for example, does not contain pores formed using a foaming agent. In other words, the dielectric layer 20, for example, does not substantially contain a foam.

[0056] Examples of porous organic structures include intrinsic microporosity polymers (PIM), metal organic frameworks (MOF), covalent organic frameworks (COF), and hydrogen-bonded organic frameworks (HOF). An example of a porous organic structure is PIM. PIM refers to a porous structure having a porous structure generated by suppressing entanglement between the main chain skeletons of a polymer.

[0057] The intrinsically microporous polymer includes, for example, a structural unit represented by the following formula (1).

[0058] [Chemical formula number 3]

[0059]

[0060] In formula (1), R1 to R 18 Each of the atoms is independently selected from the group consisting of H, B, C, N, O, F, Si, P, S, Cl, Br and I.

[0061] R1 to R 18Independently of each other, they may be a hydrogen atom, a halogen atom, a hydrocarbon group, a halogenated hydrocarbon group, a group containing an oxygen atom, a group containing a nitrogen atom, a group containing a sulfur atom, a group containing a silicon atom, a group containing a phosphorus atom, or a group containing a boron atom.

[0062] Examples of the halogen atom include F, Cl, Br, and I. In this specification, a halogen atom may be referred to as a halogen group.

[0063] The number of carbon atoms in the hydrocarbon group is not particularly limited, and may be, for example, 1 to 20, 1 to 10, or 1 to 5. The hydrocarbon group may be linear, branched, or cyclic.

[0064] Examples of the hydrocarbon group include an aliphatic saturated hydrocarbon group, an alicyclic hydrocarbon group, an aliphatic unsaturated hydrocarbon group, and the like. The aliphatic saturated hydrocarbon group may be an alkyl group. Examples of the aliphatic saturated hydrocarbon group include -CH3, -CH2CH3, -CH2CH2CH3, -CH(CH3)2, -CH(CH3)CH2CH3, -C(CH3)3, -CH2CH(CH3)2, -(CH2)3CH3, -(CH2)4CH3, -C(CH2CH3)(CH3)2, -CH2C(CH3)3, -(CH2)5CH3, -(CH2)6CH3, -(CH2)7CH3, -(CH2)8CH3, -(CH2)9CH3, -(CH2) 10 CH3, -(CH2) 11 CH3, -(CH2) 12 CH3, -(CH2) 13 CH3, -(CH2) 14 CH3, -(CH2) 15 CH3, -(CH2) 16 CH3, -(CH2) 17 CH3, -(CH2) 18 CH3, -(CH2) 19 Examples of alicyclic hydrocarbon groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and adamantyl. Examples of aliphatic unsaturated hydrocarbon groups include -CH=CH2, -C≡CH, -C≡CCH3, -C(CH3)=CH2, -CH=CHCH3, and -CH2CH=CH2.

[0065] The so-called halogenated hydrocarbon group means a group in which at least one hydrogen atom contained in the hydrocarbon group is replaced by a halogen atom. The halogenated hydrocarbon group may be a group in which all hydrogen atoms contained in the hydrocarbon group are replaced by halogen atoms. Examples of the halogenated hydrocarbon group include halogenated alkyl groups and halogenated alkenyl groups.

[0066] Examples of the halogenated alkyl group include -CF3, -CH2F, -CH2Br, -CH2Cl, -CH2I, and -CH2CF3. Examples of the halogenated alkenyl group include -CH=CHCF3.

[0067] The group containing an oxygen atom is, for example, a substituent having at least one selected from a hydroxyl group, a carboxyl group, an aldehyde group, an ether group, an acyl group, and an ester group.

[0068] As a substituent having a hydroxyl group, for example, a hydroxyl group itself and a hydrocarbon group having a hydroxyl group can be listed. In this substituent, the hydroxyl group can be deprotonated to -O - As the hydrocarbon group having a hydroxyl group, there are -CH2OH, -CH(OH)CH3, -CH2CH(OH)CH3, -CH2C(OH)(CH3)2 and the like.

[0069] As a substituent having a carboxyl group, for example, a carboxyl group itself and a hydrocarbon group having a carboxyl group can be listed. In this substituent, the carboxyl group can be deprotonated to -CO2 - As hydrocarbon groups having a carboxyl group, -CH2CH2COOH, -C(COOH)(CH3)2, -CH2CO2 - wait.

[0070] Examples of the substituent having an aldehyde group include an aldehyde group itself and a hydrocarbon group having an aldehyde group. Examples of the hydrocarbon group having an aldehyde group include -CH=CHCHO and the like.

[0071] As the substituent having an ether group, for example, an alkoxy group, a halogenated alkoxy group, an alkenyloxy group, an ethylene oxide group, and a hydrocarbon group having at least one of these functional groups can be listed. At least one hydrogen atom contained in the alkoxy group can be substituted by a group containing at least one atom selected from N, O, P and S. As the alkoxy group, a methoxy group, an ethoxy group, a 2-methoxyethoxy group, a butoxy group, a 2-methylbutoxy group, a 2-methoxybutoxy group, a 4-ethylthiobutoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, an undecyloxy group, a dodecyloxy group, a tridecyloxy group, a tetradecyloxy group, a pentadecyloxy group, a hexadecyloxy group, a heptadecyloxy group, an octadecyloxy group, a nonadecyloxy group, an eicosyloxy group, -OCH2O can be listed. - 、-OCH2CH2O - 、-O(CH2)3O - Examples of halogenated alkoxy groups include -OCHF2, -OCH2F, -OCH2Cl, etc. Examples of alkenyloxy groups include -OCH=CH2, etc. Examples of hydrocarbon groups having a functional group such as an alkoxy group include -CH2OCH3, -C(OCH3)3, 2-methoxybutyl, 6-methoxyhexyl, etc.

[0072] Examples of the substituent having an acyl group include an acyl group itself and a hydrocarbon group having an acyl group. Examples of the acyl group include -COCH3 and the like. Examples of the hydrocarbon group having an acyl group include -CH=CHCOCH3 and the like.

[0073] As the substituent having an ester group, for example, an alkoxycarbonyl group, an acyloxy group, and a hydrocarbon group having at least one of these functional groups can be cited. As the alkoxycarbonyl group, -COOCH3, -COO(CH2)3CH3, -COO(CH2)7CH3, etc. can be cited. As the acyloxy group, -OCOCH3, etc. can be cited. As the hydrocarbon group having a functional group such as an acyloxy group, -CH2OCOCH3, etc. can be cited.

[0074] The group containing a nitrogen atom is, for example, a substituent having at least one selected from an amino group, an imino group, a cyano group, an azido group, an amide group, a carbamate group, a nitro group, a cyanamide group, an isocyanate group, and an oxime group.

[0075] Examples of substituents having an amino group include primary amino groups, secondary amino groups, tertiary amino groups, quaternary amino groups, and hydrocarbon groups having at least one of these functional groups. In the substituents, the amino group may be protonated. Examples of tertiary amino groups include -N(CH3)2. Examples of hydrocarbon groups having functional groups such as primary amino groups include -CH2NH2, -CH2N(CH3)2, -(CH2)4N(CH3)2, -CH2CH2NH3 + 、-CH2CH2NH(CH3)2 + 、-CH2CH2N(CH3)3 + wait.

[0076] Examples of the substituent having an imino group include the imino group itself and a hydrocarbon group having an imino group. Examples of the imino group include -N=CCl2 and the like.

[0077] Examples of the substituent having a cyano group include a cyano group itself and a hydrocarbon group having a cyano group. Examples of the hydrocarbon group having a cyano group include -CH2CN, -CH=CHCN, and the like.

[0078] Examples of the substituent having an azide group include an azide group itself and a hydrocarbon group having an azide group.

[0079] As a substituent having an amide group, for example, an amide group itself and a hydrocarbon group having an amide group can be listed. As an amide group, -CONH2, -NHCHO, -NHCOCH3, -NHCOCF3, -NHCOCH2Cl, -NHCOCH(CH3)2, etc. can be listed. As a hydrocarbon group having an amide group, -CH2CONH2, -CH2NHCOCH3, etc. can be listed.

[0080] Examples of the substituent having a carbamate group include a carbamate group itself and a hydrocarbon group having a carbamate group. Examples of the carbamate group include -NHCOOCH3, -NHCOOCH2CH3, and -NHCO2(CH2)3CH3.

[0081] Examples of the substituent having a nitro group include the nitro group itself and a hydrocarbon group having a nitro group. Examples of the hydrocarbon group having a nitro group include -C(NO2)(CH3)2 and the like.

[0082] Examples of the substituent having a cyanamide group include a cyanamide group itself and a hydrocarbon group having a cyanamide group. The cyanamide group is represented by -NHCN.

[0083] Examples of the substituent having an isocyanate group include an isocyanate group itself and a hydrocarbon group having an isocyanate group. The isocyanate group is represented by -N=C=O.

[0084] Examples of the substituent having an oxime group include an oxime group itself and a hydrocarbon group having an oxime group. The oxime group is represented by -CH=NOH.

[0085] The group containing a sulfur atom is, for example, a substituent having at least one selected from a thiol group, a thioether group, a sulfinyl group, a sulfonyl group, a sulfinyl group, a sulfonic acid group, an acylthio group, a sulfinamide group, a sulfonamide group, a thioamide group, a thiourea group and a thiocyanate group.

[0086] Examples of the substituent having a thiol group include a thiol group itself and a hydrocarbon group having a thiol group. A thiol group is represented by -SH.

[0087] As a substituent having a thioether group, for example, an alkylthio group, an alkyldisulfide group, an alkenylthio group, an alkynylthio group, a thiirane group, and a hydrocarbon group having at least one of these functional groups can be listed. At least one hydrogen atom contained in the alkylthio group can be substituted by a halogen group. As an alkylthio group, -SCH3, -S(CH2)F, -SCH(CH3)2, -SCH2CH3, etc. can be listed. As an alkyldisulfide group, -SSCH3, etc. can be listed. As an alkenylthio group, -SCH=CH2, -SCH2CH=CH2, etc. can be listed. As an alkynylthio group, -SC≡CH, etc. can be listed. As a hydrocarbon group having a functional group such as an alkylthio group, -CH2SCF3, etc. can be listed.

[0088] Examples of the substituent having a sulfinyl group include a sulfinyl group itself and a hydrocarbon group having a sulfinyl group. Examples of the sulfinyl group include -SOCH3 and the like.

[0089] As the substituent having a sulfonyl group, for example, a sulfonyl group itself and a hydrocarbon group having a sulfonyl group can be listed. As the sulfonyl group, -SO2CH3 can be listed. As the hydrocarbon group having a sulfonyl group, -CH2SO2CH3, -CH2SO2CH2CH3, etc. can be listed.

[0090] As a substituent having a sulfinyl group, for example, a sulfinyl group itself and a hydrocarbon group having a sulfinyl group can be listed. In this substituent, the sulfinyl group can be deprotonated to -SO2 - status.

[0091] As the substituent having a sulfonic acid group, for example, the sulfonic acid group itself and a hydrocarbon group having a sulfonic acid group can be listed. In the substituent, the sulfonic acid group can be deprotonated to -SO3 - status.

[0092] Examples of the substituent having an acylthio group include an acylthio group itself and a hydrocarbon group having an acylthio group. Examples of the acylthio group include -SCOCH3 and the like.

[0093] Examples of the substituent having a sulfinamide group include a sulfinamide group itself and a hydrocarbon group having a sulfinamide group. Examples of the sulfinamide group include -SN(CH3)2 and the like.

[0094] Examples of the substituent having a sulfonamide group include the sulfonamide group itself and a hydrocarbon group having a sulfonamide group. Examples of the sulfonamide group include -SO2NH2, -NHSO2CH3, and the like.

[0095] As a substituent having a thioamide group, for example, a thioamide group itself and a hydrocarbon group having a thioamide group can be listed. As a thioamide group, -NHCSCH3 can be listed. As a hydrocarbon group having a thioamide group, -CH2SC(NH2)2 can be listed. + wait.

[0096] Examples of the substituent having a thiourea group include a thiourea group itself and a hydrocarbon group having a thiourea group. Examples of the thiourea group include -NHCSNHCH2CH3 and the like.

[0097] Examples of the substituent having a thiocyanate group include a thiocyanate group itself and a hydrocarbon group having a thiocyanate group. Examples of the hydrocarbon group having a thiocyanate group include -CH2SCN and the like.

[0098] The group containing a silicon atom is, for example, a substituent having at least one selected from a silyl group and a siloxy group.

[0099] As a substituent having a silyl group, a silyl group itself and a hydrocarbon group having a silyl group can be listed. As a silyl group, -Si(CH3)3, -SiH(CH3)2, -Si(OCH3)3, -Si(OCH2CH3)3, -SiCH3(OCH3)2, -Si(CH3)2OCH3, -Si(N(CH3)2)3, -SiF(CH3)2, -Si(OSi(CH3)3)3, -Si(CH3)2OSi(CH3)3, etc. can be listed. As a hydrocarbon group having a silyl group, -(CH2)2Si(CH3)3, etc. can be listed.

[0100] Examples of the substituent having a silyloxy group include the silyloxy group itself and a hydrocarbon group having a silyloxy group. Examples of the hydrocarbon group having a silyloxy group include -CH2OSi(CH3)3 and the like.

[0101] The group containing a phosphorus atom is, for example, a substituent having at least one selected from a phosphine group and a phosphono group.

[0102] As a substituent having a phosphino group, for example, a phosphino group itself and a hydrocarbon group having a phosphino group can be listed. As a phosphino group, -PH2, -P(CH3)2, -P(CH2CH3)2, -P(C(CH3)3)2, -P(CH(CH3)2)2, etc. can be listed.

[0103] Examples of the substituent having a phosphonyl group include a phosphonyl group itself and a hydrocarbon group having a phosphonyl group. Examples of the hydrocarbon group having a phosphonyl group include -CH2PO(OCH2CH3)2 and the like.

[0104] The group containing a boron atom is, for example, a substituent having a boronic acid group. Examples of the substituent having a boronic acid group include a boronic acid group itself and a hydrocarbon group having a boronic acid group.

[0105] As an example, at least one selected from R7 and R8 may be an alkyl group such as methyl. 17 and R 18 At least one of R1 to R6 and R9 to R 16 It may be a hydrogen atom.

[0106] In formula (1), X is independently F, Cl, Br or I. X may be Cl.

[0107] The intrinsically microporous polymer may include a structural unit represented by the following formula (2).

[0108] [Chemical formula number 4]

[0109]

[0110] The intrinsic microporous polymer contains, for example, the structural unit represented by the above-mentioned formula (1) or the structural unit represented by the formula (2) as a main component. The intrinsic microporous polymer can be represented by the following formula (3) or (4).

[0111] [Chemical formula number 5]

[0112]

[0113]

[0114] In formula (3), R1 to R 18 and X and R1 to R described above for formula (1) 18 The same as X. In formulas (3) and (4), n is an integer.

[0115] The intrinsic microporous polymer containing the structural unit represented by formula (1) or the structural unit represented by formula (2) has a tendency to have a short π-conjugated system in the main chain skeleton. The intrinsic microporous polymer has a tendency to suppress the absorption of recording and reproducing light. In particular, the intrinsic microporous polymer has a tendency to suppress the absorption of light having a wavelength in a short wavelength range.

[0116] As described above, the porous organic structure has a porous structure. Therefore, when the porous organic structure is subjected to the nitrogen adsorption method, the amount of nitrogen adsorbed by the porous organic structure tends to be large. As an example, the amount of nitrogen adsorbed by the porous organic structure obtained by the nitrogen adsorption method is, for example, 50 cm 3 / g or more, can be 100cm 3 / g or more, can be 200cm 3 / g or above, can be 250cm 3 The upper limit of the adsorption amount A is not particularly limited, and is, for example, 1000 cm 3 / g.

[0117] The adsorption amount A of nitrogen can be determined by the following method. First, the adsorption and desorption of nitrogen is measured for the porous organic structure of the powder. The adsorption and desorption of nitrogen is measured by adjusting the relative pressure P / P0 in the range of 0 to 1 under the condition of a temperature of 77K. Based on the measurement results, an adsorption isotherm is prepared to show the relationship between the relative pressure P / P0 and the adsorption amount of nitrogen. At this time, the adsorption amount of nitrogen is converted to the value under the standard state (STP: Standard Temperature and Pressure). The adsorption amount of nitrogen when the relative pressure P / P0 is 1 is read from the adsorption isotherm and determined as the adsorption amount A.

[0118] The specific surface area a of the porous organic structure is, for example, 50 m2 / g or above, can be 100m 2 / g or above, can be 300m 2 / g or above, can be 500m 2 The upper limit of the specific surface area a is not particularly limited, but is, for example, 3000 m 2 The specific surface area a is obtained by converting the data of the adsorption isotherm described above with respect to the adsorption amount A by the BET (Brunauer-Emmett-Teller) method.

[0119] The total pore volume v of the porous organic structure is, for example, 0.1 cm 3 / g or more, can be 0.2cm 3 / g or above, can be 0.3cm 3 / g or above, can be 0.4cm 3 There is no particular upper limit on the total pore volume v, but it is, for example, 1.0 cm 3 The total pore volume v is obtained by converting the data of the adsorption isotherm described above with respect to the adsorption amount A by using the BJH (Barrett-Joyner-Halenda) method.

[0120] The average pore size d of the porous organic structure is, for example, less than 50 nm, less than 30 nm, less than 10 nm, less than 5 nm, less than 3 nm, or less than 2 nm. A porous organic structure with a small average pore size d is suitable for suppressing light scattering of recording and reproducing light. The lower limit of the average pore size d is not particularly limited, and is, for example, 0.3 nm. The average pore size d can be greater than 0.3 nm and less than 50 nm, and can be greater than 0.3 nm and less than 3 nm.

[0121] The average pore size d (nm) of the porous organic structure can be calculated by calculating the specific surface area a (m 2 / g) and total pore volume v (cm 3 The average pore diameter d is calculated by substituting the average pore diameter d into the following formula: The average pore diameter d corresponds to the diameter of a cylindrical pore when all the pores included in the porous organic structure are regarded as one cylindrical pore.

[0122] Average pore size d = 4 × 10 3 × total pore volume v / specific surface area a

[0123] The dielectric layer 20 contains, for example, a porous organic structure as a main component. The so-called "main component" means a component that is contained in the dielectric layer 20 in the largest amount by weight. The dielectric layer 20 is, for example, substantially formed of a porous organic structure. "Substantially formed of..." means that other components that change the essential characteristics of the material mentioned are excluded. However, the dielectric layer 20 may contain impurities in addition to the porous organic structure.

[0124] The thickness of the dielectric layer 20 is not particularly limited, and is, for example, 5 nm or more and 100 μm or less. However, the thickness of the dielectric layer 20 may be greater than 100 μm.

[0125] Furthermore, the dielectric layer 20 including the porous organic structure has a tendency to have high light transmittance to the recording and reproducing wavelength, especially the wavelength in the short wavelength range. The dielectric layer 20 also has a tendency to have both high thermal insulation and mechanical strength. As described later, the dielectric layer 20 has thermal insulation, so that the recording sensitivity of the optical recording medium 100 can be improved.

[0126] [Record layer]

[0127] The recording layer 10 contains, for example, an organic compound C having optical properties. The optical properties are typically light absorption properties. As an example, the organic compound C can absorb light having a wavelength in a short wavelength range and change from a ground state to a transition state. When the organic compound C returns from the transition state to the ground state, heat can be generated.

[0128] The organic compound C may have, for example, nonlinear optical properties, particularly nonlinear light absorption properties. Specifically, the organic compound C may have nonlinear optical properties for light having a wavelength in a short wavelength range. As an example of nonlinear optical properties, two-photon absorption properties may be cited. However, the organic compound C may have single-photon absorption properties for light having a wavelength in a short wavelength range. In this specification, the organic compound C having optical properties is sometimes referred to as a pigment.

[0129] The organic compound C contains at least one selected from a carbon-carbon double bond, a carbon-nitrogen double bond and a carbon-carbon triple bond. The organic compound C may further contain an aromatic ring. The aromatic ring contained in the organic compound C may be composed of carbon atoms, or may be a heteroaromatic ring containing heteroatoms such as oxygen atoms, nitrogen atoms, and sulfur atoms. As the aromatic ring contained in the organic compound C, for example, a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a furan ring, a pyrrole ring, a pyridine ring, a thiophene ring, etc. can be listed. The organic compound C may contain a benzene ring as an aromatic ring. There is no particular limitation on the number of aromatic rings contained in the organic compound C, for example, it is 2 or more, it may be 3 or more, it may be 5 or more. There is no particular limitation on the upper limit of the number of aromatic rings, for example, 15. In the organic compound C, a plurality of aromatic rings may be connected by at least one bond selected from a carbon-carbon double bond, a carbon-nitrogen double bond and a carbon-carbon triple bond. The plurality of aromatic rings contained in the organic compound C may be the same as or different from each other.

[0130] A specific example of the organic compound C is a dye 28Ev represented by the following formula (5). The dye 28Ev is a compound having a two-photon absorption property for light having a wavelength in a short wavelength range.

[0131] [Chemical formula number 6]

[0132]

[0133] Other examples of the organic compound C include coumarin 6. Coumarin 6 is a compound having a single-photon absorption property for light having a wavelength in a short wavelength range.

[0134] The content of the organic compound C in the recording layer 10 is, for example, less than 50% by weight, 30% by weight or less, or 10% by weight or less. The lower limit of the content of the organic compound C is not particularly limited, and is, for example, 2% by weight.

[0135] The recording layer 10 may further contain a resin that functions as a binder in addition to the organic compound C. A specific example of the resin is polyvinylcarbazole.

[0136] The content of the resin in the recording layer 10 is, for example, 50% by weight or more, 70% by weight or more, or 90% by weight or more. The upper limit of the content of the resin is not particularly limited, but is, for example, 98% by weight.

[0137] The recording layer 10 is a thin film having a thickness of, for example, 1 nm or more and 100 μm or less. However, the thickness of the recording layer 10 may exceed 100 μm.

[0138] [Method for producing optical recording medium]

[0139] The optical recording medium 100 can be produced, for example, by the following method. First, the material of the recording layer 10 is mixed with a solvent to produce a coating liquid. As the solvent, for example, a low-polarity solvent can be used. The coating liquid is applied to a substrate by a spin coating method, and the obtained coating film is dried to produce a thin film recording layer 10.

[0140] Next, the porous organic structure is mixed with a solvent to prepare a coating liquid. As the solvent, for example, a highly polar solvent can be used. The coating liquid is applied to the recording layer 10 by a method such as spin coating, and the obtained coating film is dried to prepare the dielectric layer 20. As required, a plurality of recording layers 10 and a plurality of dielectric layers 20 are alternately prepared to obtain the optical recording medium 100.

[0141] Furthermore, in the case of the intrinsic microporous polymer containing the structural unit represented by formula (1) or the structural unit represented by formula (2), a cation is generated by introducing a hydrogen atom or a substituent such as an alkyl group into the nitrogen atom. Therefore, the intrinsic microporous polymer has hydrophilicity and is soluble in a highly polar solvent. In this case, a coating liquid containing the intrinsic microporous polymer can be applied to the hydrophobic recording layer to form a dielectric layer.

[0142] [How to use optical recording media]

[0143] The optical recording medium 100 of this embodiment uses light having a wavelength in a short wavelength range, for example. As an example, the optical recording medium 100 uses light having a wavelength of 390 nm or more and 420 nm or less. The light used in the optical recording medium 100 has a high photon density near its focus, for example. The power density near the focus of the light used in the optical recording medium 100 is, for example, 0.1 W / cm 2 Above and 1.0×10 20 W / cm 2 The power density near the focus of the light can be 1.0W / cm 2 Above, can be 1.0×10 2 W / cm 2 Above, can be 1.0×10 5 W / cm 2 As the light source used in the optical recording medium 100 , for example, a femtosecond laser such as a titanium sapphire laser or a pulse laser having a pulse width of picoseconds to nanoseconds such as a semiconductor laser can be used.

[0144] Next, a method of recording information using the optical recording medium 100 will be described. Figure 2AThis is a flowchart related to a method for recording information using an optical recording medium 100. First, in step S11, a light source that emits light having a wavelength of greater than 390 nm and less than 420 nm is prepared. As the light source, for example, a femtosecond laser such as a titanium sapphire laser or a pulse laser such as a semiconductor laser having a pulse width of picoseconds to nanoseconds can be used. Secondly, in step S12, the light from the light source is focused by a lens or the like, and irradiated onto the recording layer 10 in the optical recording medium 100. In detail, the light from the light source is focused by a lens or the like, and irradiated onto the recording area in the optical recording medium 100. There is no particular restriction on the NA (numerical aperture) of the lens used for focusing light. As an example, a lens having an NA in the range of greater than 0.8 and less than 0.9 can be used. The power density near the focus of the light is, for example, 0.1 W / cm 2 Above and 1.0×10 20 W / cm 2 The power density near the focus of the light can be 1.0W / cm 2 Above, can be 1.0×10 2 W / cm 2 Above, can be 1.0×10 5 W / cm 2 In this specification, the recording area refers to a site that exists in the recording layer 10 and can record information by irradiating light.

[0145] In the above-mentioned recording area irradiated with light, physical changes or chemical changes occur, thereby changing the optical characteristics of the recording area. For example, the intensity of light reflected in the recording area, the reflectivity of light in the recording area, the absorptivity of light in the recording area, the refractive index of light in the recording area, the intensity of fluorescent light emitted from the recording area, the wavelength of fluorescent light, etc. change. As an example, the intensity of light reflected in the recording area or the intensity of fluorescent light emitted from the recording area decreases. As a result, information can be recorded in the recording layer 10, more specifically, in the recording area (step S13).

[0146] Next, a method of reading information using the optical recording medium 100 will be described. Figure 2BThis is a flowchart related to a method for reading information using an optical recording medium 100. First, in step S21, the recording layer 10 in the optical recording medium 100 is irradiated with light. Specifically, the recording area in the optical recording medium 100 is irradiated with light. The light used in step S21 may be the same as or different from the light used to record information in the optical recording medium 100. Next, in step S22, the optical properties of the recording layer 10 are measured. Specifically, the optical properties of the recording area are measured. In step S22, for example, as the optical properties of the recording area, the intensity of light reflected in the recording area or the intensity of fluorescent light emitted from the recording area is measured. In step S22, as the optical properties of the recording area, the reflectivity of light in the recording area, the absorptivity of light in the recording area, the refractive index of light in the recording area, the wavelength of fluorescent light emitted from the recording area, etc. can be measured. Next, in step S23, information is read from the recording layer 10, specifically, from the recording area.

[0147] In the information reading method, the recording area where information is recorded can be found by the following method. First, light is irradiated to a specific area of ​​the optical recording medium. The light may be the same as or different from the light used to record information on the optical recording medium. Next, the optical characteristics of the area irradiated with light are measured. As optical characteristics, for example, the intensity of light reflected in the area, the reflectivity of light in the area, the absorptivity of light in the area, the refractive index of light in the area, the intensity of fluorescent light emitted from the area, the wavelength of fluorescent light emitted from the area, etc. can be listed. Based on the measured optical characteristics, it is determined whether the area irradiated with light is a recording area. For example, when the intensity of light reflected in the area is below a specific value, it is determined that the area is a recording area. On the other hand, when the intensity of light reflected in the area exceeds a specific value, it is determined that the area is not a recording area. Furthermore, the method for determining whether the area irradiated with light is a recording area is not limited to the above method. For example, when the intensity of light reflected in the area exceeds a specific value, it can be determined that the area is a recording area. In addition, when the intensity of light reflected in the area is below a specific value, it can be determined that the area is not a recording area. When it is determined that the area is not a recording area, the same operation can be performed on other areas of the optical recording medium, thereby making it possible to find the recording area.

[0148] The information recording method and reading method using the optical recording medium 100 can be performed using a known recording device. The recording device includes, for example, a light source for irradiating light to a recording area in the optical recording medium 100, a measuring device for measuring optical characteristics of the recording area, and a controller for controlling the light source and the measuring device.

[0149] In the optical recording medium 100 of this embodiment, when recording light is irradiated to the recording layer 10, the organic compound C absorbs the recording light and changes from the ground state to the transition state. When the organic compound C returns from the transition state to the ground state, for example, heat is generated. With this heat, for example, the binder present in the recording area is degraded, and a recording mark is formed.

[0150] In the optical recording medium 100 of the present embodiment, the dielectric layer 20 has pores caused by a porous organic structure. Due to the heat insulation effect of the air in the pores, for example, it is possible to suppress the heat generated in the recording layer 10 during the recording operation from being released from the recording layer 10. Since the heat generated in the recording layer 10 is effectively used in the recording layer 10, the recording sensitivity of the optical recording medium 100 is improved.

[0151] The recording sensitivity of the optical recording medium 100 can be evaluated, for example, by the following method. First, a recording light is irradiated onto the recording layer 10 of the optical recording medium 100 using a laser. As a result, the shape of the resin contained in the recording layer 10 changes near the focus where the light from the laser is concentrated. The minimum light irradiation energy required to produce this change is determined, and is regarded as the minimum light irradiation energy required for recording. Based on the light irradiation energy, the recording sensitivity of the optical recording medium 100 can be evaluated. Furthermore, the evaluation of the recording sensitivity can be performed based on the pulse width related to the light irradiation energy. With respect to the optical recording medium 100 of this embodiment, a recording light with a shorter pulse width can be used for recording operation compared with the past.

[0152] Example

[0153] Hereinafter, the present disclosure will be described in more detail using examples. It should be noted that the following examples are just examples, and the present disclosure is not limited to the following examples.

[0154] [Synthesis of intrinsically microporous polymers]

[0155] First, a precursor of an intrinsically microporous polymer represented by the following formula (6) was prepared (manufactured by Sigma-Aldrich Corporation).

[0156] [Chemical formula number 7]

[0157]

[0158] Next, 200 mg of the above-mentioned precursor and 0.2 mL of 12 mol / L hydrochloric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added to 5 mL of diacetone alcohol (manufactured by Tokyo Chemical Industry Co., Ltd.), and the mixture was stirred at 50°C for 1 hour. Thus, the precursor reacted with the hydrochloric acid to synthesize the above-mentioned inherent microporous polymer represented by formula (4). The reaction solution was cooled to room temperature, and the diacetone alcohol and hydrochloric acid were removed by vacuum distillation to obtain the target inherent microporous polymer of formula (4). The inherent microporous polymer is prepared by 1 H-NMR and solid 13 C-NMR identification. Figure 3 Solids representing inherently microporous polymers 13 C-NMR spectrum of intrinsically porous polymers 1 H-NMR spectra and solid 13 The C-NMR spectrum is as follows.

[0159] 1 H NMR (500MHz, DMSO d6): δ(ppm)7.26-6.83(br,m,4H),4.84-4.60(br,s,2H),4.24(br,s,4H),3.47(br,s),1.83(br,m),1.42(br,m,4H). Solid 13 C NMR: δ (ppm) 158.6-136.7, 130.0-112.1, 80.8, 67.6, 58.2, 41.8, 39.5-32.3, 25.6-14.9.

[0160] The nitrogen adsorption amount A, specific surface area a, total pore volume v and average pore diameter d of the obtained intrinsically microporous polymer were measured by the above-mentioned method.

[0161] Table 1

[0162]

[0163] (Example 1)

[0164] First, a coating liquid for a recording layer containing a material for a recording layer was prepared. Specifically, 1 g of polyvinyl carbazole (PVK) and 105 mg of coumarin 6 pigment were added to 20 mL of dichlorobenzene, and the coating liquid for a recording layer was prepared by heating and stirring at 80°C for 12 hours. Secondly, a coating liquid for a dielectric layer containing a material for a dielectric layer was prepared. Specifically, 200 mg of a precursor of the above-mentioned inherent microporous polymer represented by formula (6) and 1 mL of hydrochloric acid with a concentration of 12 mol / L were added to 5 mL of diacetone alcohol, and the mixture was stirred at room temperature for 1 hour to prepare a coating liquid for a dielectric layer. In the coating liquid for the dielectric layer, an inherent microporous polymer represented by formula (4) was synthesized.

[0165] Next, a recording layer coating liquid was applied onto a quartz substrate using a spin coater, and the coating film was dried to produce a recording layer. Furthermore, a dielectric layer coating liquid was applied onto the recording layer using a spin coater, and the coating film was dried to produce a dielectric layer. Thus, an optical recording medium of Example 1 in which a dielectric layer was laminated on a recording layer was obtained. In the optical recording medium of Example 1, the dielectric layer had pores caused by an intrinsic microporous polymer.

[0166] (Example 2)

[0167] An optical recording medium of Example 2 was obtained by the same method as in Example 1 except that 53 mg of the dye 28Ev represented by the formula (5) was used instead of the coumarin 6 dye.

[0168] (Comparative Example 1)

[0169] An optical recording medium of Comparative Example 1 was obtained by the same method as in Example 1 except that 1 g of cellulose acetate was added to 24 mL of diacetone alcohol and stirred at 80° C. for 12 hours to prepare a dielectric layer coating liquid. Since cellulose acetate does not have a porous structure, the dielectric layer does not have a porous structure in the optical recording medium of Comparative Example 1. The fact that a layer of cellulose acetate can be stacked on a layer containing polyvinylcarbazole is disclosed in, for example, Thin Solid Films, 2007, Vol. 515, pp. 3887-3892.

[0170] (Comparative Example 2)

[0171] An optical recording medium of Comparative Example 2 was obtained in the same manner as in Comparative Example 1 except that 53 mg of the dye 28Ev represented by the formula (5) was used instead of the coumarin 6 dye.

[0172] <Measurement of recording sensitivity>

[0173] For the optical recording medium of the embodiment and the comparative example, a recording light having a central wavelength of 405 nm and a peak power of 100 mW was passed through a lens of NA0.85 and irradiated with one pulse to perform a recording operation. For this recording operation, the pulse width of the recording light was adjusted in the range of 10 nanoseconds to 5 milliseconds, and the recording operation was repeated. Thus, the minimum pulse width required to form a recording mark on the recording layer was determined. The results are shown in Table 2.

[0174] Table 2

[0175]

[0176] As can be seen from Table 2, the optical recording medium of the example including the dielectric layer containing the porous organic structure, ie, the intrinsic microporous polymer, has a shorter minimum pulse width required for recording than the comparative example, and the recording sensitivity is improved.

[0177] Industrial Applicability

[0178] The optical recording medium disclosed herein can be used in applications such as three-dimensional optical storage.

[0179] Description of Reference Numerals

[0180] 10 Recording Layer

[0181] 20 Dielectric layer

[0182] 100 Optical recording medium.

Claims

1. An optical recording medium, comprising: a recording layer; and a dielectric layer located on the recording layer and comprising a porous organic structure.

2. The optical recording medium according to claim 1, wherein The porous organic structure has a 50m 2 / g or more specific surface area.

3. The optical recording medium according to claim 1, wherein The porous organic structure has an average pore diameter of 0.3 nm or more and 50 nm or less.

4. The optical recording medium according to claim 1, wherein The porous organic structure has an average pore diameter of 0.3 nm or more and 3 nm or less.

5. The optical recording medium according to claim 1, wherein The porous organic structure is an inherently microporous polymer.

6. The optical recording medium according to claim 5, wherein The intrinsically microporous polymer comprises a structural unit represented by the following formula (1): [Chemical formula number 1] In the formula (1), R1 to R 18 They independently contain at least one atom selected from H, B, C, N, O, F, Si, P, S, Cl, Br and I, and X is independently F, Cl, Br or I.

7. The optical recording medium according to claim 5, wherein The intrinsically microporous polymer comprises a structural unit represented by the following formula (2): [Chemical formula number 2] 8. The optical recording medium according to claim 1, wherein The recording layer contains an organic compound having nonlinear optical characteristics.

9. The optical recording medium according to claim 8, wherein The nonlinear optical property is a two-photon absorption property.

10. A method for recording information, comprising: preparing a light source that emits light having a wavelength of 390 nm or more and 420 nm or less; and concentrating the light from the light source and irradiating the light to the recording layer in the optical recording medium according to any one of claims 1 to 9.

11. A method for reading information, which is a method for reading information recorded by the recording method according to claim 10, the reading method comprising: measuring optical properties of the recording layer by irradiating the recording layer in the optical recording medium with light; and reading information from the recording layer.

12. The reading method according to claim 11, wherein: The optical characteristic is the intensity of light reflected by the recording layer.

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