JP2009002970A - Manufacturing method for microlens and microlens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for simply and inexpensively manufacturing a microlens having high accuracy in shape and in-plane disposition of the lens. <P>SOLUTION: In this manufacturing method for the microlens, a resin sheet contains an acid generation agent generating acid or a base generation agent generating base by action of an active energy line and further contains a chemical compound having a decomposition functional group for decomposing and desorbing one or more kinds of low boiling point volatile material by interaction with acid or base, the active energy line is applied to the resin sheet, which is then heated to cause decomposition reaction, and fine bubbles are formed to have distribution in plane direction or thickness direction in the resin sheet by the generated low boiling point volatile material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a microlens used in fields such as optical communication, a digital camera, and a light diffusion film for a project screen, and particularly provides a method for manufacturing a flat microlens with low manufacturing cost and excellent productivity. .

In recent years, with the development of optical communication technology, higher integration of optical components has been promoted. In order to miniaturize and increase the integration of optical lenses that connect them, instead of conventional spherical lenses, aspherical lenses and micro lenses are used. Lens arrays have been commercialized. On the other hand, even in CCDs, which are essential devices for digital cameras that are rapidly spreading, devices with microlenses attached to each of a large number of solid-state image sensors formed on a wafer are mounted and put into practical use. Yes. In addition, it is also used for a light diffusion film for making the light of the projection screen uniform.
Various methods have been proposed as a manufacturing method of the microlens used in these. For example, a method of making a mold by hot pressing with a mold (stamper), a method of changing the refractive index by changing the degree of photopolymerization (see Patent Document 1), and partially covering the glass surface with a mask And then etching (see Patent Document 2), a method of increasing the volume of the light-irradiated portion using the movement of the photoreactive substance (see Patent Document 3), and after forming a film with a resist material A method of reacting by light irradiation to elute an irradiated portion or a non-irradiated portion (see Patent Document 4), a method of forming a pattern with a resin and then melting it into a lens shape (see Patent Document 5), etc. Can be mentioned.

  In the method of forming a microlens with a mold, since a thermoplastic resin is produced in a heated state, both the mold and the resin are affected by thermal expansion, so that there is a drawback that the position accuracy of the array cannot be obtained. Since the lithography process is usually performed at a temperature controlled in a clean room, there is an advantage that there is no influence of thermal expansion and a pattern with high positional accuracy can be produced. However, in the method described in the above publication, the degree of elution is reduced. It is difficult to control precisely, and as a result, it is difficult to manufacture with good reproducibility.

On the other hand, as in Patent Document 1, in the method of manufacturing a microlens having a refractive index change due to a change in polymerization degree by light irradiation, the degree of refractive index change is very small, and the function as a lens is limited. . It is difficult to precisely control the shape of the lens by a method of etching glass or a method of thermally melting a patterned resin, and it is difficult to design an optical component optimized for the application.
Japanese Patent No. 3553929 Japanese Patent Publication No. 7-23237 Japanese Patent No. 2541584 Japanese Patent No. 3003808 Japanese Patent No. 3317506

  It is an object of the present invention to provide a method for easily and inexpensively manufacturing a microlens having high accuracy of lens shape and in-plane arrangement.

As a result of intensive studies on the above-mentioned problems, an acid generator or base that generates an acid by the action of active energy rays, as well as creating a lens without foaming part of the resin sheet and creating physical irregularities. It is heated after irradiating a resin containing a decomposable functional group that reacts with an acid or base and decomposes or desorbs one or more low-boiling volatile substances with active energy rays. Thus, the present invention was completed by forming a foamed portion in which fine bubbles are gathered in the resin.
That is, the manufacturing method of the microlens according to the present invention employs the following configuration.

  According to a first aspect of the present invention, an “acid generator that generates an acid or a base generator that generates a base by the action of an active energy ray in a method for manufacturing a sheet-like resin microlens in which a large number of microlenses are arranged” In addition, the resin sheet containing a compound having a decomposable functional group that reacts with an acid or a base to decompose and desorb one or more low-boiling volatile substances is irradiated with active energy rays and then heated. A method for producing a microlens, characterized in that fine bubbles are formed in a resin sheet so as to have a distribution in a plane direction and a thickness direction by a low boiling volatile substance generated by a decomposition reaction.

  A second aspect of the present invention is the method for producing a microlens according to the first aspect, wherein the average bubble diameter of fine bubbles formed in the resin is 500 nm or less.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the microbubble volume fraction is 5 to 90% in the foamed portion formed in the resin. Is the method.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the invention, when the active energy ray is irradiated, the transmittance of the active energy ray is continuous from the center of one lens forming portion to the outside. A manufacturing method of a microlens using a changing mask.

  According to a fifth aspect of the present invention, in the resin sheet, a large number of fine bubbles are aggregated to form a fine convex lens-shaped or concave lens-shaped foamed portion, and the lens-shaped foamed portions are arranged in a two-dimensional direction. This is a microlens.

As described above, the present invention contains an acid generator that generates an acid by the action of an active energy ray or a base generator that generates a base, and further reacts with an acid or a base to produce one or more low-boiling point volatilizations. The resin containing a decomposable functional group that decomposes and desorbs the active substance is irradiated with an active energy ray and then heated to cause a decomposition reaction, so that fine bubbles of 500 nm or less in the resin have a volume fraction of 5 to 95%. As described above, the microlens can be manufactured with high accuracy and at low cost by forming the foamed portion so that the distribution is different between the front and back surfaces of the resin and partially controlling the refractive index of the resin.
In addition, the microlens of the present invention has an advantage that there is no unevenness on the surface, and the microlens can be bonded closely to other planar members without gaps.

  According to this method, it is possible to control the change in the refractive index in a wide range by adjusting the intensity of the light to be irradiated and the heat to be reacted, and it is possible to achieve both the accuracy and the simple method that were difficult with the conventional method. This is advantageous in terms of cost as compared with the conventional manufacturing method.

The implementation of the present invention will be described as follows.
First, in the present invention, a lens means not a convex lens or concave lens with physical irregularities but a lens having the same function as a convex lens or concave lens. In this specification, a microlens refers to an assembly of lenses, and when referring to individual lenses, this is clearly indicated. The sheet refers to a thin film shape to a relatively thick plate shape.
The composition used as the raw material of the resin used for the microlens constituting the present invention will be described. The resin composition is a composition in which at least one low boiling point volatile substance is expressed by irradiating active energy rays and performing a heat treatment. The resin composition is desirably a composition in which at least the following two components coexist. One is an acid generator that generates an acid by the action of active energy rays, or a base generator that generates a base, and the other is one or more types that react with the generated acid or base. It is a decomposable compound that decomposes and desorbs the low boiling point volatility.

<Acid generator and base generator>
The acid generator or base generator used in the resin composition used in the present invention includes a chemically amplified photoresist, a photoacid generator or a photobase generator generally used for photocationic polymerization, and the like. What is called can be used.

Suitable photoacid generators for the present invention include (1) diazonium salt compounds (2) ammonium salt compounds (3) iodonium salt compounds (4) sulfonium salt compounds (5) oxonium salt compounds (6) PF ₆ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ and CF ₃ SO ₃ ^— salts of aromatic or aliphatic onium compounds selected from phosphonium salt compounds and the like can be mentioned.
Although the specific example is enumerated below, it is not limited to what was illustrated.
Bis (phenylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (tert-butylsulfonyl) diazomethane, bis (p-methylphenylsulfonyl) diazomethane, bis (4-chlorophenylsulfonyl) diazomethane, bis (p-tolylsulfonyl) diazomethane Bis (4-tert-butylphenylsulfonyl) diazomethane, bis (2,4-xylylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, benzoylphenylsulfonyldiazomethane, trifluoromethanesulfonate, trimethylsulfonium trifluoromethanesulfonate, triphenylsulfonium Trifluoromethanesulfonate, triphenylsulfonium hexafluoroantimonate 2,4,6-trimethylphenyldiphenylsulfonium trifluoromethanesulfonate, p-tolyldiphenylsulfonium trifluoromethanesulfonate, 4-phenylthiophenyldiphenylsulfonium hexafluorophosphate, 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate, 1- (2 -Naphthoylmethyl) thiolanium hexafluoroantimonate, 1- (2-naphthoylmethyl) thiolanium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldimethylsulfonium hexafluoroantimonate, 4-hydroxy-1-naphthyldimethylsulfonium Trifluoromethanesulfonate, (2-oxo-1-cyclohexyl) (cyclohexyl) methylsulfoniu Trifluoromethanesulfonate, (2-oxo-1-cyclohexyl) (2-norbornyl) methylsulfonium trifluoromethanesulfonate, diphenyl-4-methylphenylsulfonium perfluoromethanesulfonate, diphenyl-4-tert-butylphenylsulfonium perfluorooctanesulfonate, Diphenyl-4-methoxyphenylsulfonium perfluorobutanesulfonate, diphenyl-4-methylphenylsulfonium tosylate, diphenyl-4-methoxyphenylsulfonium tosylate, diphenyl-4-isopropylphenylsulfonium tosylate diphenyliodonium, diphenyliodonium tosylate, diphenyl Iodonium chloride, diphenyliodonium hexafluo Loarsenate, diphenyliodonium hexafluorophosphate, diphenyliodonium nitrate, diphenyliodonium perchlorate, diphenyliodonium trifluoromethanesulfonate, bis (methylphenyl) iodonium trifluoromethanesulfonate, bis (methylphenyl) iodonium tetrafluoroborate, bis (methylphenyl) Iodonium hexafluorophosphate, bis (methylphenyl) iodonium hexafluoroantimonate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium hexafluorophosphate, bis (4- tert-Butylphenyl) iodonium hexafluo Antimonate, bis (4-tert-butylphenyl) iodonium perfluorobutanesulfonate, 2-methyl-4,6-bis (trichloromethyl) -1,3,5-triazine, 2,4,6-tri (trichloromethyl) ) -1,3,5-triazine, 2-phenyl-4,6-ditrichloromethyl-1,3,5-triazine, 2- (p-methoxyphenyl) -4,6-ditrichloromethyl-1,3 , 5-triazine, 2-naphthyl-4,6-ditrichloromethyl-1,3,5-triazine, 2-biphenyl-4,6-ditrichloromethyl-1,3,5-triazine, 2- (4 ′ -Hydroxy-4-biphenyl) -4,6-ditrichloromethyl-1,3,5-triazine, 2- (4'-methyl-4-biphenyl) -4,6-ditrichloromethyl- , 3,5-triazine, 2- (p-methoxyphenylvinyl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-chlorophenyl) -4,6-bis (trichloro Methyl) -1,3,5-triazine, 2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-methoxy-1-naphthyl)- 4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (benzo [d] [1,3] dioxolan-5-yl) -4,6-bis (trichloromethyl) -1,3 , 5-triazine, 2- (4-methoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (3,4,5-trimethoxystyryl) -4,6- Bis (trichloromethyl) -1,3,5 Triazine, 2- (3,4-dimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (2,4-dimethoxystyryl) -4,6-bis (trichloromethyl) ) -1,3,5-triazine, 2- (2-methoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-butoxystyryl) -4,6- Bis (trichloromethyl) -1,3,5-triazine, 2- (4-pentyloxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2,6-di-tert- Butyl-4-methylpyrylium trifluoromethanesulfonate, trimethyloxynium tetrafluoroborate, triethyloxynium tetrafluoroborate, N-hydroxyphthalimide Trifluoromethanesulfonate, N-hydroxynaphthalimide trifluoromethanesulfonate, (αbenzoylbenzyl) p-toluenesulfonate, (β-benzoyl-β-hydroxyphenethyl) p-toluenesulfonate, 1,2,3-benzenetriyltrismethane Examples include sulfonate, (2,6-dinitrobenzyl) p-toluenesulfonate, (2-nitrobenzyl) p-toluenesulfonate, (4-nitrobenzyl) p-toluenesulfonate, and the like. Of these, iodonium salt compounds and sulfonium salt compounds are preferred.

In addition to the onium compounds, sulfonates that generate sulfonic acid upon irradiation with active energy rays, such as 2-phenylsulfonylacetophenone, halides that generate hydrogen halide upon irradiation with active energy rays, such as phenyltribromo. Methylsulfone and 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethane, and ferrocenium compounds that generate phosphoric acid upon irradiation with active energy rays, such as bis (cyclopentadienyl) ferrocenium hexa Fluorophosphate, bis (benzyl) ferrocenium hexafluorophosphate, and the like can be used.
Furthermore, the following imide compound derivatives having acid generating ability can also be used. N- (phenylsulfonyloxy) succinimide, N- (trifluoromethylsulfonyloxy) succinimide, N- (10-camphorsulfonyloxy) succinimide, N- (trifluoromethylsulfonyloxy) phthalimide, N- (trifluoromethylsulfonyloxy) ) -5-norbornene-2,3-dicarboximide, N- (trifluoromethylsulfonyloxy) naphthalimide, N- (10-camphorsulfonyloxy) naphthalimide.

  Examples of the photobase generator suitable for the present invention include (1) oxime ester compounds, (2) ammonium compounds, (3) benzoin compounds, (4) dimethoxybenzyl urethane compounds, and (5) orthonitrobenzyl urethane compounds. They generate amines as bases upon irradiation with active energy rays. In addition, a base generator that generates ammonia or hydroxy ions by the action of light may be used. These include, for example, N- (2-nitropentyloxycarbonyl) piperidine, 1,3-bis [N- (2-nitrobenzyloxycarbonyl) -4-piperidyl] propane, N, N′-bis (2-nitrobenzyl). It can be selected from oxycarbonyl) dihexylamine, O-benzylcarbonyl-N- (1-phenylethylidene) hydroxylamine, and the like. Further, a compound that generates a base by heating may be used in combination with the photobase generator.

  In addition, a photosensitizer may be used in combination as appropriate in order to shift or expand the wavelength region of the active energy ray of the photoacid generator or photobase generator. For example, examples of photosensitizers for onium salt compounds include acridine yellow, benzoflavin, and acridine orange.

  As a method of minimizing the amount of addition of the acid generator or base generator and the light irradiation energy while generating the necessary acid, it is possible to use an acid multiplier or base multiplier together with the acid generator or base generator. it can. The acid proliferator is thermodynamically stable at around room temperature, but decomposes with acid and generates a strong acid by itself to greatly accelerate the acid-catalyzed reaction. By utilizing this reaction, it is possible to improve the generation efficiency of acid or base and control the production rate of low boiling point volatile substances.

<Degradable compounds>
The decomposable compound used in the present invention reacts with an acid or a base to decompose and desorb one or more low-boiling volatile substances (low-boiling volatile compounds). That is, this decomposable compound must be previously introduced with a degradable functional group capable of generating a low boiling point volatile substance. The low boiling point is the upper limit of the temperature at which gasification occurs during foaming. Usually, it is preferably 100 ° C. or lower and room temperature or lower. Examples of the low boiling point volatile substance include isobutene (boiling point: −7 ° C.), carbon dioxide (boiling point: −79 ° C.), nitrogen (boiling point: −196 ° C.), and the like. Examples of the decomposable functional group include tert-butyl group, tert-butyloxycarbonyl group, keto acid and keto ester group as those that react with acid, and urethane group and carbonate group as those that react with base. Can be mentioned. Reacting with acid includes tert-butyl group, tert-butyloxycarbonyl group, and acid, tert-butyl group is isobutene gas, tert-butyloxycarbonyl group is isobutene gas and carbon dioxide, keto Acid sites generate carbon dioxide and ketoesters such as the tert-butyl keto acid group generate carbon dioxide and isobutene. As those that react with the base, urethane groups and carbonate groups generate carbon dioxide gas. In this way, each gas is released from the decomposable compound. The form of an acid-decomposable compound that decomposes by reacting with an acid or a base-decomposable compound that decomposes by reacting with a base can be used as a monomer, oligomer, polymer compound (polymer), etc. It can be classified into such compound groups. (1) Non-curing low molecular weight decomposable compound group (2) Curing monomer based degradable compound group (3) Polymerizable degradable compound group Examples represented by curable monomer based degradable compounds In the case of an active energy ray-curable compound containing a vinyl group that causes a polymerization reaction when irradiated with an active energy ray, it is easy to uniformly decompose and obtain a microlens with excellent accuracy. Is possible. Although the specific example of a decomposable compound is enumerated below, it is not limited to what was illustrated.

(1) -a, non-curing low molecular weight decomposable compound group <acid decomposable compound>
1-tert-butoxy-2-ethoxyethane, 2- (tert-butoxycarbonyloxy) naphthalene, N- (tert-butoxycarbonyloxy) phthalimide, 2,2-bis [p- (tert-butoxycarbonyloxy) phenyl] Propane, etc.

(1) -b, non-curing low molecular weight decomposable compound group <base decomposable compound>
N- (9-fluorenylmethoxycarbonyl) piperidine, etc.

(2) -a, curable monomer-based decomposable compound group <acid-decomposable compound>
tert-butyl acrylate, tert-butyl methacrylate, tert-butoxycarbonylmethyl acrylate, 2- (tert-butoxycarbonyl) ethyl acrylate, p- (tert-butoxycarbonyl) phenyl acrylate, p- (tert-butoxycarbonylethyl) phenyl acrylate 1- (tert-butoxycarbonylmethyl) cyclohexyl acrylate, 4-tert-butoxycarbonyl-8-vinylcarbonyloxy-tricyclo [5.2.1.02,6] decane, 2- (tert-butoxycarbonyloxy) ethyl Acrylate, p- (tert-butoxycarbonyloxy) phenyl acrylate, p- (tert-butoxycarbonyloxy) benzyl acrylate, 2- (tert-butyl) Xoxycarbonylamino) ethyl acrylate, 6- (tert-butoxycarbonylamino) hexyl acrylate, p- (tert-butoxycarbonylamino) phenyl acrylate, p- (tert-butoxycarbonylamino) benzyl acrylate, p- (tert-butoxycarbonyl) Aminomethyl) benzyl acrylate, (2-tert-butoxyethyl) acrylate, (3-tert-butoxypropyl) acrylate, (1-tert-butyldioxy-1-methyl) ethyl acrylate, 3,3-bis (tert-butyloxy) Carbonyl) propyl acrylate, 4,4-bis (tert-butyloxycarbonyl) butyl acrylate, p- (tert-butoxy) styrene, m- (tert-butoxy) s N- (tert-butoxycarbonyloxy) styrene, p- (tert-butoxycarbonyloxy) styrene, m- (tert-butoxycarbonyloxy) styrene, acryloyl acetate, methacryloyl acetate, tert-butyl acryloyl acetate, tert-butyl methacryloyl acetate, etc. Oxy) maleimide

(2) -b, curable monomer group decomposable compound group <base decomposable compound>
4-[(1,1-dimethyl-2-cyano) ethoxycarbonyloxy] styrene, 4-[(1,1-dimethyl-2-phenylsulfonyl) ethoxycarbonyloxy] styrene, 4-[(1,1-dimethyl -2-methoxycarbonyl) ethoxycarbonyloxy] styrene, 4- (2-cyanoethoxycarbonyloxy) styrene, (1,1-dimethyl-2-phenylsulfonyl) ethyl methacrylate, (1,1-dimethyl-2-cyano) Ethyl methacrylate, etc.

(3) -a, decomposable compound group of polymer system <acid-decomposable compound>
Poly (tert-butyl acrylate), poly (tert-butyl methacrylate), poly (tert-butoxycarbonylmethyl acrylate), poly [2- (tert-butoxycarbonyl) ethyl acrylate], poly [p- (tert-butoxycarbonyl) Phenyl acrylate], poly [p- (tert-butoxycarbonylethyl) phenyl acrylate], poly [1- (tert-butoxycarbonylmethyl) cyclohexyl acrylate], poly {4-tert-butoxycarbonyl-8-vinylcarbonyloxy-tricyclo [5.2.1.02,6] decane}, poly [2- (tert-butoxycarbonyloxy) ethyl acrylate], poly [p- (tert-butoxycarbonyloxy) phenyl acrylate], poly [P- (tert-butoxycarbonyloxy) benzyl acrylate], poly [2- (tert-butoxycarbonylamino) ethyl acrylate], poly [6- (tert-butoxycarbonylamino) hexyl acrylate], poly [p- (tert -Butoxycarbonylamino) phenyl acrylate], poly [p- (tert-butoxycarbonylamino) benzyl acrylate], poly [p- (tert-butoxycarbonylaminomethyl) benzyl acrylate], poly (2-tert-butoxyethyl acrylate) , Poly (3-tert-butoxypropyl acrylate), poly [(1-tert-butyldioxy-1-methyl) ethyl acrylate], poly [3,3-bis (tert-butyloxycarbonyl) pro Acrylate], poly [4,4-bis (tert-butyloxycarbonyl) butyl acrylate], poly [p- (tert-butoxy) styrene], poly [m- (tert-butoxy) styrene], poly [p- (Tert-butoxycarbonyloxy) styrene], poly [m- (tert-butoxycarbonyloxy) styrene], polyacryloylacetic acid, polymethacryloylacetic acid, poly [tert-butylacryloylacetate], poly [tert-butylmethacloyl] Acetate] N- (tert-butoxycarbonyloxy) maleimide / styrene copolymer, etc.

(3) -b, decomposable compound group of polymer system <base decomposable compound>
Poly {p-[(1,1-dimethyl-2-cyano) ethoxycarbonyloxy] styrene}, poly {p-[(1,1-dimethyl-2-phenylsulfonyl) ethoxycarbonyloxy] styrene}, poly {p -[(1,1-dimethyl-2-methoxycarbonyl) ethoxycarbonyloxy] styrene}, poly [p- (2-cyanoethoxycarbonyloxy) styrene], poly [(1,1-dimethyl-2-phenylsulfonyl) Ethyl methacrylate], poly [(1,1-dimethyl-2-cyano) ethyl methacrylate], and the like.

  Organic polymer compounds such as polyethers, polyamides, polyesters, polyimides, polyvinyl alcohols and dendrimers into which degradable functional groups are introduced can be used as acid-decomposable or base-decomposable polymer compounds. Furthermore, an acid-decomposable or base-decomposable polymer compound in which a decomposable functional group is introduced into an inorganic compound such as silica is also included. Especially, it is preferable that a decomposable functional group is introduce | transduced into the compound group which has a functional group chosen from the group which consists of a carboxylic acid group or a hydroxyl group, and an amine group.

  Among these polymer compounds into which a degradable functional group has been introduced, polymer compounds having excellent optical properties and heat resistance are particularly suitable for microlens applications. Preferred examples include polyimide, polycarbonate, fluorine-based resin (particularly a fluorine-based aliphatic ring structure-containing polymer), epoxy resin, silicone resin, polysilane, and cyanate ester resin.

  The decomposable compound group may be used alone or in combination of two or more different types. Moreover, the decomposable compound can be used by mixing with other resins. When mixed, the decomposable compound and the other resin may be either compatible or incompatible. Other resins include polyester resins such as polyethylene terephthalate and polybutylene terephthalate, unsaturated polyester resins, polycarbonate resins, polyolefin resins such as polyethylene and polypropylene, polyolefin composite resins, polystyrene resins, polybutadiene resins, (meth) acrylic resins, Acryloyl resin, ABS resin, fluororesin, polyimide resin, polyacetal resin, polysulfone resin, vinyl chloride resin, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, starch, polyvinyl alcohol, polyamide resin, phenol resin, melamine resin, urea resin, urethane resin, It can be appropriately selected from commonly used resins such as epoxy resins and silicone resins.

  Among the decomposable foaming compounds, the curable monomer-based decomposable compound group and the polymer-based decomposable compound group may be used singly or in combination with the generally used resins. On the other hand, since the non-curable low molecular weight decomposable compound group cannot be molded alone, it is necessary to use it by mixing with the generally used resin.

In order to increase the moisture resistance of the microlens of the present invention, a compound in which a decomposable functional group is introduced into a compound containing at least one kind of hydrophobic functional group can also be used as the decomposable composition. The hydrophobic functional group used in the present invention is preferably selected from the group consisting mainly of an aliphatic group, an alicyclic group, an aromatic group, a halogen group, and a nitrile group. The decomposable and foamable functional group is easily introduced into a hydrophilic functional group selected from the group consisting mainly of a carboxylic acid group, a hydroxyl group and an amine group. Therefore, the decomposable compound of the present invention is preferably a composite compound comprising a decomposable unit having a degradable functional group introduced into the hydrophilic functional group and a hydrophobic unit containing a hydrophobic functional group. In the more preferable composite compound, the decomposable unit and the hydrophobic unit are vinyl polymers. Hydrophobic units include aliphatic (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate, aromatic vinyl compounds such as styrene, methylstyrene and vinylnaphthalene, (meth) acrylonitrile compounds, vinyl acetate A compound group, a vinyl chloride compound group, etc. are mentioned. As a representative example of the decomposable compound, the decomposable unit is tert-butyl acrylate in which a tert-butyl group which is a decomposable functional group is introduced into acrylic acid having a carboxylic acid group of a hydrophilic functional group, and Examples thereof include vinyl copolymers comprising a combination in which the hydrophobic unit is methyl acrylate having a hydrophobic functional group methyl group. Specific examples of the decomposable compound comprising a combination of degradable unit / hydrophobic unit are shown below. tert-butyl acrylate / methyl methacrylate copolymer tert-butyl methacrylate / methyl acrylate copolymer tert-butyl methacrylate / methyl methacrylate copolymer tert-butyl acrylate / ethyl acrylate copolymer tert-butyl acrylate / ethyl methacrylate copolymer Tert-butyl methacrylate / ethyl acrylate copolymer tert-butyl methacrylate / ethyl methacrylate copolymer tert-butyl acrylate / styrene copolymer tert-butyl acrylate / vinyl chloride copolymer tert-butyl acrylate / acrylonitrile copolymer p -(Tert-Butoxycarbonyloxy) styrene / styrene copolymer In addition, a degradable unit in the decomposable compound and The hydrophobic unit can be used alone or in combination of two or more. The form of copolymerization can be performed arbitrarily such as random copolymerization, block copolymerization, and graft copolymerization. In addition, the copolymerization ratio of the hydrophobic unit is preferably 1 to 95% by mass with respect to the total amount of the decomposable compound, and considering the decomposable foamability of the decomposable compound and the environmental preservation of the foamed structure, 5 to 80 The mass% is more preferable.

The decomposable compounds may be used alone or in combination of two or more different types.
The decomposable compound is a compound containing at least one kind of hydrophobic functional group after the decomposable functional group is decomposed and eliminated to generate a low boiling point volatile substance.

  In order to increase the moisture resistance of the microlens of the present invention, the decomposable composition has a low moisture absorption of less than 10% as measured by the JIS K-7209D method in an environmental atmosphere at a temperature of 30 ° C and a relative humidity of 60%. A compound in which a decomposable functional group is introduced into a functional compound can also be used. Examples of the low hygroscopic compound having a structure in which a degradable functional group can be easily introduced include p-hydroxystyrene and m-hydroxystyrene. Accordingly, examples of the decomposable compound include p- (tert-butoxy) styrene, m- (tert-butoxy) styrene, p- (tert-butoxycarbonyloxy) styrene, and m- (tert-butoxycarbonyloxy) styrene. These may be a curable monomer or a polymer in which one or more kinds are mixed.

Further, a degradable functional group may be introduced into a composite compound composed of a combination of a highly hygroscopic compound having a water absorption of 10% or more and a low hygroscopic compound having a water absorption of less than 10%. However, the composite compound preferably has a water absorption of less than 10% by an appropriate combination. For example, a copolymer (composite compound) of acrylic acid, which is a highly hygroscopic compound, and p-hydroxystyrene, which is a low hygroscopic compound, has a copolymerization ratio of acrylic acid / p-hydroxystyrene = 90 / 10-0 / 100 is preferred. Specific examples of the decomposable compound include tert-butyl acrylate / p- (tert-butoxy) styrene copolymer tert-butyl acrylate / m- (tert-butoxy) styrene copolymer tert-butyl acrylate / p- (Tert-Butoxycarbonyloxy) styrene copolymer tert-butyl acrylate / m- (tert-butoxycarbonyloxy) styrene copolymer tert-butyl methacrylate / p- (tert-butoxycarbonyloxy) styrene copolymer A degradable functional group may be introduced into a low hygroscopic polymer material selected from the group consisting of polyester, polyimide, polyvinyl acetate, polyvinyl chloride, polyacrylonitrile, phenol resin, and dendrimer.

  The decomposable compounds may be used alone or in combination of two or more different types. The decomposable compound becomes a low hygroscopic compound after the decomposable functional group is decomposed and eliminated to generate a low boiling point volatile substance.

<Degradable composition>
In addition to the acid generator or base generator and the decomposable compound, other active energy ray-curable unsaturated organic compounds may be used in combination for the decomposable composition used in the present invention. Examples of combined compounds include (1) (meth) acrylates of aliphatic, alicyclic, and aromatic 1- to 6-valent alcohols and polyalkylene glycols (2) aliphatic, alicyclic, and aromatic 1 (Meth) acrylates of compounds obtained by adding alkylene oxide to 6-valent alcohol (3) poly (meth) acryloylalkyl phosphate esters (4) polybasic acid, polyol, (meth) acrylic acid, Reaction product of (5) Reaction product of isocyanate, polyol, (meth) acrylic acid (6) Reaction product of epoxy compound and (meth) acrylic acid (7) Reaction of epoxy compound, polyol, (meth) acrylic acid Product (8) The reaction product of melamine and (meth) acrylic acid, etc. can be mentioned.

Among the compounds that can be used in combination, curable monomers and resins can be expected to have an effect of improving physical properties such as the strength and heat resistance of microlenses and a volume shrinkage control effect. Moreover, if a curable monomer is used for the decomposable compound and the combination compound, solvent-free molding can be performed, and a production method with less environmental load can be provided. Examples include the following materials.
Specific examples of the combination compound include methyl acrylate, ethyl acrylate, lauryl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, caprolactone-modified tetrahydrofurfuryl acrylate, cyclohexyl acrylate, cyclohexyl methacrylate, dicyclohexyl acrylate, isobornyl acrylate, isobornyl methacrylate, benzyl acrylate , Benzylmeta Acrylate, ethoxydiethylene glycol acrylate, methoxytriethylene glycol acrylate, methoxypropylene glycol acrylate, phenoxy polyethylene glycol acrylate, phenoxy polypropylene glycol acrylate, ethylene oxide modified phenoxy acrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, 2-ethylhexyl carbitol acrylate, ω-carboxypolycaprolactone monoacrylate, phthalic acid monohydroxyethyl acrylate, acrylic acid dimer, 2-hydroxy-3-phenoxypropyl acrylate, acrylic acid-9,10-epoxidized oleyl, ethylene maleate Glycol monoacrylate, disic Pentenyloxyethylene acrylate, acrylate of caprolactone adduct of 4,4-dimethyl-1,3-dioxolane, acrylate of caprolactone adduct of 3-methyl-5,5-dimethyl-1,3-dioxolane, polybutadiene acrylate, ethylene oxide modified Phenoxylated phosphate acrylate, ethanediol diacrylate, ethanediol dimethacrylate, 1,3-propanediol diacrylate, 1,3-propanediol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol di Methacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol diacrylate, 1,9-nonanediol dimethacrylate, di Ethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, neopentyl glycol diacrylate, 2-butyl-2-ethylpropanediol diacrylate, ethylene oxide modified bisphenol A diacrylate, Polyethylene oxide modified bisphenol A diacrylate, polyethylene oxide modified hydrogenated bisphenol A diacrylate, propylene oxide modified bisphenol A diacrylate, polypropylene oxide modified bisphenol A diacrylate, ethylene oxide modified isocyanuric acid diacrylate, pentaerythritol diacrylate monostearate 1,6-hexanediol diglycidyl ether acrylic acid adduct, polyoxyethylene epichlorohydrin modified bisphenol A diacrylate, trimethylolpropane triacrylate, ethylene oxide modified trimethylolpropane triacrylate, polyethylene oxide modified trimethylolpropane triacrylate, Propylene oxide modified trimethylolpropane triacrylate, polypropylene oxide modified trimethylolpropane triacrylate, pentaerythritol triacrylate, ethylene oxide modified isocyanuric acid triacrylate, ethylene oxide modified glycerol triacrylate, polyethylene oxide modified glycerol triacrylate, propylene oxide modified glycerol triacrylate Polypropylene oxide modified glycerol triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, caprolactone modified dipentaerythritol hexaacrylate, polycaprolactone modified Although dipentaerythritol hexaacrylate etc. can be mentioned, it is not restricted to these.

  Further, as part or all of the combined active energy ray-curable unsaturated organic compound, an active energy ray-curable resin having a (meth) acryloyl group at the molecular chain terminal and having a molecular weight of about 400 to 5000 can be combined. . As such a curable resin, for example, polyurethane poly (meth) acrylate polymers such as polyurethane-modified polyether poly (meth) acrylate and polyurethane-modified polyester poly (meth) acrylate are preferably used.

  Depending on the ratio of the decomposable functional group in the decomposable composition used in the present invention, the volume shrinkage after reaction and volatilization varies. A suitable mass ratio of the degradable functional group is 5 to 50%, more preferably 10 to 30%. If it is 50% or more, the hydrophilicity becomes too strong and the moisture resistance is extremely lowered. If it is less than 5%, the reaction takes time, and the volume change is reduced.

  The decomposable composition used in the present invention can contain additives other than the decomposable compound, if necessary. Additives include polyisocyanate compounds, epoxy compounds, reactive compounds such as organometallic compounds and antioxidants, silicone oils and processing aids, UV absorbers, fluorescent brighteners, antislip agents, antistatic agents, One or more antiblocking agents, antifogging agents, light stabilizers, lubricants, softeners, colored dyes, other stabilizers, and the like may be included. By using the additive, improvement in moldability and uniformity can be expected.

  Specific examples of the ultraviolet absorber are selected from salicylic acid-based, benzophenone-based, or benzotriazole-based ultraviolet absorbers. Examples of salicylic acid-based ultraviolet absorbers include phenyl salicylate, pt-butylphenyl salicylate, p-octylphenyl salicylate, and the like. Examples of the benzophenone ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone. Examples of the benzotriazole ultraviolet absorber include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-5'-t-butylphenyl) benzotriazole and the like.

Specific examples of the antioxidant include monophenol-based, bisphenol-based, polymer-type phenol-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like.
A typical example of the light stabilizer is a hindered amine compound.
The softening agent can be used for the purpose of improving moldability or processability of the molded body. Specifically, ester compounds, amide compounds, hydrocarbon polymers having side chains, mineral oils, liquid paraffins, Examples thereof include waxes.
The ester compound is not particularly limited as long as it is a mono- or polyester having a structure comprising an alcohol and a carboxylic acid, and may be a compound in which the hydroxyl group and carbonyl group ends are left in the molecule, or a compound blocked in the form of an ester group. . Specifically, stearyl stearate, sorbitan tristearate, epoxy soybean oil, refined castor oil, hydrogenated castor oil, dehydrated castor oil, epoxy soybean oil, extremely hardened oil, trioctyl trimellitic acid, ethylene glycol dioctanoate, pentaerythritol tetra Examples include octanoate.
The amide compound is not particularly limited as long as it is a mono- or polyamide compound having a structure composed of an amine and a carboxylic acid, and may be a compound in which the amino group and carbonyl group ends are left in the molecule, or a compound blocked in the form of an amide group. Good. Specifically, stearic acid amide, behenic acid amide, hexamethylene bis stearic acid amide, trimethylene bisoctylic acid amide, hexamethylene bishydroxy stearic acid amide, triocta trimellitic acid amide, distearyl urea, butylene bis stearic acid Amides, xylylene bis stearic acid amides, distearyl adipic acid amides, distearyl phthalic acid amides, distearyl octadecadioic acid amides, epsilon caprolactam, and derivatives thereof.

  The hydrocarbon polymer having a side chain is preferably a poly α-olefin and classified into a normal oligomer having a side chain having 4 or more carbon atoms. Specifically, ethylene-propylene copolymer and its maleic acid derivative, isobutylene polymer, butadiene, isoprene oligomer and hydrogenated product thereof, 1-hexene polymer, polystyrene polymer and the like are derived from these. Derivatives thereof, hydroxypolybutadiene and hydrogenated products thereof, and terminal hydroxypolybutadiene hydrogenated products.

  The decomposable composition used in the present invention can be prepared using a general kneader. For example, two rolls, three rolls, cowless resolver, homomixer, sand grinder, planetary mixer, ball mill, kneader, high speed mixer, homogenizer, and the like. An ultrasonic disperser or the like can also be used.

<Manufacturing process of micro lens>
The manufacturing process of the microlens of the present invention includes a step of irradiating an active energy ray to a decomposable composition, a step of foaming by controlling the temperature in a temperature range where a low boiling point volatile substance is decomposed and desorbed from the decomposable composition, and including.
In order to stably obtain a microlens having a desired thickness, shape and structure, the manufacturing method of the present invention can include a preforming step. The preliminary molding step is a molding step provided before the step of irradiating active energy rays, and is a step of molding a decomposable composition that is a resin before decomposition.
First, the process of irradiating the decomposable composition with active energy rays will be described. Examples of active energy rays used in the present invention include ionizing radiation such as electron beams, ultraviolet rays, visible rays, and γ rays. In these, it is preferable to use an electron beam and an ultraviolet-ray.

  When electron beam irradiation is used, the acceleration voltage may be adjusted to 20 to 100 kV according to the thickness of the decomposable composition, and more preferably a curtain type electron beam irradiation apparatus or electron beam drawing under the condition of 30 to 300 kV. It is preferable to use an apparatus. If the accelerating voltage is lower than the above range, the transmission power of the electron beam becomes insufficient, and the inside of the molded body cannot be sufficiently transmitted. If it is larger than this range, the energy efficiency is not only deteriorated. In some cases, the strength of the obtained molded article becomes insufficient, the resin and additives contained therein are decomposed, and the quality of the obtained foam is unsatisfactory. When the oxygen concentration in the irradiation atmosphere is high during electron beam irradiation, generation of acid or base and / or curing of the curable decomposable compound may be hindered. Substitution with an inert gas such as carbon is preferred. The oxygen concentration in the irradiation atmosphere is preferably 1000 ppm or less, and more preferably 500 ppm or less in order to obtain more stable electron beam energy.

In the case of ultraviolet irradiation, an ultraviolet lamp generally used in the semiconductor / photoresist field or the ultraviolet curing field can be used. Typical UV lamps include, for example, halogen lamps, halogen heater lamps, xenon short arc lamps, xenon flash lamps, ultra high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, medium pressure mercury lamps, deep UV lamps, metal halide lamps. There are noble gas fluorescent lamps, krypton arc lamps, excimer lamps, etc., and in recent years, there are also Y-ray lamps that emit an extremely short wavelength (peak at 214 nm). Some of these lamps are ozone-less types that generate less ozone. These ultraviolet rays may be scattered light or parallel light with high straightness. In order to form partial foaming accurately, parallel light is preferable. For ultraviolet irradiation, various lasers such as ArF excimer laser, KrF excimer laser, YAG laser via a harmonic unit including a nonlinear optical crystal, and ultraviolet light emitting diodes may be used. The emission wavelength of the ultraviolet lamp, laser, or ultraviolet light emitting diode is not limited as long as it does not interfere with the foaming property of the decomposable composition. Preferably, the photoacid generator or the photobase generator makes the acid or base efficient. The emission wavelength that is often generated is good. That is, an emission wavelength that overlaps with the photosensitive wavelength region of the photoacid generator or photobase generator to be used is preferable. Furthermore, the light emission wavelength which overlaps the maximum absorption wavelength or the maximum absorption wavelength in the photosensitive wavelength region of these generators is more preferable, and the generation efficiency tends to increase. The intensity of ultraviolet energy irradiation is appropriately determined depending on the decomposable composition. When using UV lamps with high irradiation intensity, such as various mercury lamps and metal halide lamps, productivity can be improved, and the irradiation intensity (lamp output) is 30 W / cm or more for long arc lamps. Is preferred. The integrated irradiation light quantity (J / cm ² ) of ultraviolet rays is obtained by adding the irradiation time to the energy irradiation intensity, and is appropriately determined depending on the foam composition and the desired bubble distribution. It may be set according to the extinction coefficient of the acid generator or base generator. For stable and continuous production, a range of 1.0 mJ / cm ^{2 to 20} J / cm ² is preferable. When using an ultraviolet lamp, the irradiation time can be shortened because the irradiation intensity is high. When an excimer lamp or excimer laser is used, the irradiation intensity is weak, but it is close to a single light, so if the emission wavelength is optimized for the photosensitive wavelength of the generator, higher generation efficiency and foamability Is possible. When the amount of irradiation light is increased, heat generation may interfere with foaming properties depending on the ultraviolet lamp. At that time, a cooling treatment such as a cold mirror can be performed.

In the microlens manufacturing method of the present invention, in order to obtain a patterned lens portion, active energy rays can be irradiated using a photomask so that an intensity distribution of active energy is generated in the irradiation step. When a photomask including a drawing pattern is used, an intensity distribution of active energy rays to which the drawing pattern is transferred can be obtained. As a photomask drawing pattern, the part that does not foam the resin is shielded with a mask, a pattern is created so that the active energy ray hits the foamed part, and energy transmission is used as a means to adjust the bubble volume fraction of the foamed part. Various things such as the one having the gradation can be appropriately designed depending on the application. Photomasks include chrome masks, metal masks, silver salt glass masks, silver salt films, screen masks, glass ion-etched masks, and masks with electron beam-drawing interference fringes on planar lenses that have a condensing function. it can. A mask obtained by printing a drawing pattern on a photomask substrate with a printer using an ink jet printer or an ultraviolet curable ink can also be used as a mask. Printing may be performed on one side or both sides of the substrate.
In addition, in order to change the bubble distribution in the thickness direction, by including a material in the resin in which the irradiated active energy rays are moderately attenuated inside the resin, the active energy ray irradiation side is strong and the opposite side is The strength can be adjusted to be weak. In addition, the bubble distribution in the thickness direction can be changed by combining a lens with a mask to control the irradiation amount of the active energy ray in the thickness direction, or by adding a temperature difference between the front and the back during heating.

  In order to increase the printing accuracy of the drawing pattern, it is preferable to modify the surface of the substrate to be printed. As a specific example of the modification treatment, a functional layer that enhances the absorbability of the ink to be printed is provided on the surface of the substrate by a coating method or an adhesion method. However, this functional layer must not significantly impair the basic optical performance of the photomask. Further, the ink to be used is preferably a material that absorbs, scatters, or reflects active energy rays, while the photomask base material is preferably a material that transmits active energy rays. When irradiating ultraviolet rays with a wavelength of 300 nm or less, it is preferable to use quartz glass as the base material of the photomask. As an irradiation method using a photomask, methods such as contact irradiation and projection irradiation can be adopted. In order to transfer the pattern of the photomask with high accuracy, it is preferable that the irradiated light is uniform parallel light. Examples of the exposure system for irradiating parallel light include an optical system using an integrator and a parabolic mirror, an optical system using a Fresnel lens, and an optical system using a honeycomb board and a diffusion plate. In order to obtain high uniformity, an optical system using an integrator and a parabolic mirror is generally preferable, and a short arc lamp is preferable as a light source used in this optical system. Examples of the short arc lamp include a metal halide lamp, an ultra-high pressure mercury lamp, a mercury xenon lamp, a sodium lamp, and a Y-ray lamp. Further, a method of irradiating radiation that generates interference fringes is also possible.

  Next, in the step of foaming by applying thermal energy, the heating foaming step is preferably performed after the radiation irradiation step when only fine bubbles are produced. A stable foam can be formed by sequentially performing the radiation irradiation step and the heating step. This is because the foaming mechanism of the resin is a mechanism in which an acid or a base is generated by radiation, and the decomposition foamable compound is decomposed and foamed by the acid or base and heating. The resin generates a large number of bubble nuclei at a relatively low temperature, and when the temperature is further increased to grow the bubbles, fine bubbles can be made uniform. However, if the temperature is raised from the beginning and radiation is applied to it, large bubbles will be formed.

  The steps in the method for producing a microlens of the present invention are not limited to these, and various other steps can be added at appropriate desired portions. For example, processes such as a stretching process, a cleaning process, a drying process, and a relaxation process may be appropriately introduced. The production method of the present invention comprises a combination of these steps, and the steps can be combined discontinuously or continuously, or at least two steps can be simultaneous steps. Either the batch method or the continuous method may be used. Furthermore, in the microlens manufacturing method of the present invention, since the active energy intensity distribution, the thermal energy intensity distribution, the concentration distribution of the decomposable composition, and the like can be added, the control of the shape of the microlens is arbitrarily variable. Although the specific example of each process is demonstrated below, this invention is not limited.

First, the step of foaming by controlling the pressure in a temperature range where the low boiling point volatile substance is decomposed and desorbed from the foamable composition will be described. As an example of the pressure control method, as shown in FIG. 1, a pressure control method is performed by applying pressure only from the opposing surfaces using two plates, and the pressure control method is partially opposed, using a mold as shown in FIG. For example, an overall pressure control method in which pressure is controlled by pressurization. Further, there are a type in which the pressure can be varied according to the pushing force without having a gap control function as shown in FIGS. 1 and 2, and a type having a gap control function as in FIGS. In the case of the entire surface pressure control method, pressure control is performed by injecting a fluid such as gas, liquid, or melt into a closed mold, and pressure control is performed by the foam self-expanding force by foaming of the foamable composition and the generated gas pressure. And a method of controlling the pressure by the thermal expansion force of the mold and the mold contents.
In order to obtain a temperature region in which the low boiling point volatile substance is decomposed and desorbed, it is possible to use a heater or to use the remaining heat when heat is applied in the previous step. The temperature range where the low boiling point volatile substance decomposes and desorbs from the foamable composition is higher than the minimum temperature at which the low boiling point volatile substance decomposes and desorbs. That is, it refers to a temperature range in a range lower than the temperature at which various physical properties such as the decomposition temperature or strength of the foam resin are not impaired. This temperature range varies depending on the type of foamable composition. For example, in the case of an acrylic foamable composition, the minimum decomposition and desorption temperature is about 75 to 85 ° C, and the decomposition temperature of the foam resin is about 180 to 200 ° C. The minimum temperature is about 65 to 80 ° C, and the decomposition temperature of the foam resin is about 160 to 180 ° C. The higher the temperature during foaming, the higher the decomposition and desorption rate of the low boiling point volatile substances, and the higher the degree of supersaturation. However, the higher the temperature, the lower the resin viscosity, and bubbles tend to grow and coalesce and become larger. Therefore, there exists a temperature range suitable for foaming. The region varies depending on the type of the foamable composition, but is 65 to 200 ° C, preferably 90 to 180 ° C, and more preferably 100 to 160 ° C. Although there is no restriction | limiting in particular in the heater which can be used at a foaming process, What can be heated by contact heating, induction heating, resistance heating, dielectric heating (and microwave heating), infrared heating, etc. can be illustrated. Specific examples include an electric or gas infrared dryer using radiant heat, a roll heater using electromagnetic induction, an oil heater using an oil medium, an electric heater, and a hot air dryer using these hot airs. It is done. In contact heating in which a heating body is brought into contact with the molded body and heated, a heating body such as a metal block, a metal plate, or a metal roll can be used. In contact heating, heating may be performed while applying pressure. In this case, a hot press machine used for press molding can be used.

In the case of dielectric heating and infrared heating, since the internal heating method directly heats the inside of the material, it is preferable to perform uniform heating instantaneously compared to an external heating method such as a hot air dryer. In the case of dielectric heating, high frequency energy with a frequency of 1 MHz to 300 MHz (wavelength 30 m to 1 m) is used. A frequency of 6 MHz to 40 MHz is often used. Among dielectric heating, especially microwave heating uses a microwave with a frequency of 300 MHz to 300 GHz (wavelength is 1 m to 1 mm), but 2450 MHz and 915 MHz (same as a microwave oven) are often used.
In the case of infrared heating, an electromagnetic wave having a wavelength in the infrared region of 0.76 to 1000 μm is used. Although the optimum band of the selected wavelength varies depending on the situation from the heater surface temperature and the infrared absorption spectrum of the material to be heated, a wavelength band of preferably 1.5 to 25 μm, more preferably 2 to 15 μm can be used.

  In the production method of the present invention, in order to obtain a microlens having a controlled refractive index, heat treatment can be performed so that a thermal energy intensity distribution is generated in the surface and on the front and back surfaces. The intensity distribution of thermal energy is preferably adjusted by the heating temperature. As a method of creating the intensity distribution of thermal energy, a heating method used in general thermal recording printers is applied, that is, minute heat generation that generates heat by passing a current like a print head used in thermal printers. Examples include a method of controlling a heating part by a heating body in which a large number of bodies are arranged, a method of controlling a heating part by laser irradiation such as a laser heating head used in a laser printer, and the like.

  The preforming step included in the method for manufacturing a microlens of the present invention will be described. As a molding method used in the preliminary molding step, coating molding, extrusion molding, injection molding, cast molding, press molding, or the like can be selected according to the shape to be molded. The resin shape obtained in the molding step is not particularly limited, and can be appropriately determined depending on the purpose of use of the microlens. Examples include sheet-like materials (including film-like materials), fiber-like materials, rod-like materials, and materials having other desired shapes. The sheet-like material may be a single sheet-like material or a sheet layer in close contact with the support, or may be a laminated structure of a plurality of resins. Furthermore, it is possible to use a method in which the final shape of the microlens or a shape close thereto is formed in multiple stages.

  As an example of coating molding, after applying the decomposable composition to the support, if the decomposable composition is a solution diluted with a solvent or the like, the solvent content is removed with a dryer, Examples thereof include a method for obtaining a sheet layer made of a decomposable composition. At this time, it is also possible to obtain a single sheet-like material composed of the decomposable composition by peeling the sheet layer from the support. Coating methods include spin coating, bar coating, air doctor coating, blade coating, squeeze coating, air knife coating, roll coating, gravure coating, transfer coating, comma coating, and smoothing coating. Method, microgravure coating method, reverse roll coating method, multi-roll coating method, dip coating method, rod coating method, kiss coating method, gate roll coating method, falling curtain coating method, slide coating method, fountain coating method, and slit die coating method Etc. Examples of the support include Si wafer substrate, paper, synthetic paper, plastic resin sheet, metal sheet, metal vapor deposition sheet and the like, and these may be used alone or may be laminated with each other. . The plastic resin sheet is, for example, a general-purpose plastic sheet such as a polystyrene resin sheet, a polyolefin resin sheet such as polyethylene or polypropylene, and a polyester resin sheet such as polyethylene terephthalate, an engineering resin such as a polyimide resin sheet, an ABS resin sheet, or a polycarbonate resin sheet. A plastic sheet etc. are mentioned, Moreover, aluminum, copper, etc. are mentioned as a metal which comprises a metal sheet. Examples of the metal deposition sheet include an aluminum deposition sheet, a gold deposition sheet, and a silver deposition sheet.

Examples of the extrusion molding method include a general extrusion molding method using a screw-like extrusion shaft, and a ram extrusion molding method using a piston-like extrusion shaft.
Examples of injection molding methods include, in addition to the normal injection molding method, vacuum filling molding method, injection compression molding method, high-speed vacuum filling molding method, gas absorption melt molding method, mold thermal cooling / heating cycle molding method, low-pressure low-speed filling molding method. Method, injection press molding method, stack mold molding method and the like. The methods for thin-wall molding and high-transfer rate molding of fine shapes, which are the latest trends, are the heat-insulating mold molding method, the ultra-high-speed injection molding method with an injection speed of 1000 to 2000 mm / sec. Examples include an injection molding method using a supercritical fluid in which an active gas is dissolved in a molten resin in a supercritical state and molded without foaming.
As an example of cast molding, a liquid-degradable composition containing an active energy ray-curable monomer is cast into an arbitrary mold, cured by irradiating active energy rays, and demolded to obtain an arbitrarily shaped microlens. The method etc. are mentioned. It is also possible to separate the resin curing and the acid and base generation from the acid and base generator by appropriately selecting the irradiation conditions such as the light source and wavelength of the active energy ray.

In the structure of the microlens formed by the above manufacturing method, the porosity of the foamed portion is 5 to 90%, preferably 10 to 50%, more preferably 10 to 40%. If the porosity is too low, the difference in refractive index between the foamed part and the unfoamed part is small, and the effect as a lens is small.
One microlens as an element of the microlens of the present invention is represented by a schematic diagram as shown in FIG. 5, for example. In FIG. 5, the upper stage is a plan view and the lower stage is a cross-sectional view, and the left side of FIG. 5 has a concave lens type function and the right side has a convex lens type function. A large number of such microlenses arranged in both the vertical and horizontal directions of the plane is the microlens of the present invention. Each microlens may be arranged in contact with each other with no gap, or arranged at a fixed interval. Also good.

  The present invention will be described in detail by the following examples, but the present invention is not limited to these examples. Unless otherwise specified, “parts” and “%” in the examples represent “parts by mass” and “mass%”, respectively.

<Example 1> (1) Decomposable composition For 100 parts of a copolymer of tert-butyl acrylate (20%), tert-butyl methacrylate (40%) and methyl methacrylate (40%) as degradable compounds. Thus, a decomposable composition having a mixing ratio of 3 parts of bis (4-tert-butylphenyl) iodonium perfluorobutanesulfonate (trademark: BBI-109, manufactured by Midori Chemical) is used as an iodonium salt-based acid generator.

(2) Preliminary molding step A 25% solution of the decomposable composition having the above-described mixing ratio was prepared as a coating solution using a dilution solution of MEK / ethyl acetate = 65/35 (mass ratio). This coating solution (FIG. 6a) is coated using an applicator having a clearance of 300 μm on the silicone-treated surface of a support made of 75 μm thick silicone PET (FIG. 6b) (trademark: MR-75: manufactured by Mitsubishi Polyester). Then, it is left in a constant temperature drier at a temperature of 110 ° C. for 10 minutes to evaporate and remove the diluted solution. After removing the sample from the constant temperature dryer, the coating layer is peeled off from the silicone PET to obtain a decomposable composition film having a thickness of 45 μm.

(3) Ultraviolet irradiation Quartz plate in which a mask by chrome plating is applied to the decomposable composition film in the step (2) so that ultraviolet rays are applied to the foamed portion of the microlens (the white portion in the figure) (see FIG. 6c) is superimposed on the film and irradiated with ultraviolet rays at an irradiation dose of 2000 mJ / cm ^{2 using} a metal halide lamp (trade name: multi-metal lamp for ultraviolet curing M03-L31, manufactured by Eyegraphic Co., Ltd.) as a light source. 6d).

(4) Foaming step Each irradiated sheet obtained in the step (3) is cut out at 5 cm × 6 cm, sandwiched between 10 cm × 10 cm and 1 mm thick SUS plates, and hand press machine (trade name: Mini TEST PRES manufactured by TOYOSEIKI). -10), press the hot plate for 10 minutes while controlling the hot plate so that only the upper surface is heated at 150 ° C. with the pressure of 6 MPa applied to the laminated sample. After the press is released, the sample can be taken out from the press machine while being sandwiched between SUS plates and naturally air-cooled to obtain a microlens (FIG. 6e).

As described above, the present invention contains an acid generator that generates an acid by the action of an active energy ray or a base generator that generates a base, and further reacts with an acid or a base to produce one or more kinds of low-boiling-point volatility. A resin containing a degradable functional group that decomposes and desorbs a substance is irradiated with active energy rays and then heated to cause a decomposition reaction so that the fine bubbles of 500 nm or less in the resin have a volume fraction of 50 to 95%. The microlens can be precisely and inexpensively manufactured by partially forming and controlling the refractive index of the resin. Therefore, the present invention greatly contributes to the miniaturization of the microlens array, and can be used not only in the resin industry for processing a polymer material into a microlens, but also in the material industry, as well as the optical for manufacturing a specific optical component. The present invention can be widely applied to equipment-related industries and optoelectronic equipment-related industries related to display devices.

Pressure control method using a plate (no gap control function) Pressure control method using mold (no gap control function) Pressure control method using a plate (with gap control function) Pressure control method using a mold (with gap control function) Schematic diagram showing one microlens according to the present invention. It is a schematic diagram which shows the manufacturing method of the microlens concerning this invention.

Explanation of symbols

1 Foamable composition (plate-like)
2 Pressure control plate (no gap adjustment function)
3 Upper mold of pressure control mold 4 Lower mold of pressure control mold (no gap adjustment function)
5 Pressure control plate (with gap adjustment function)
6 Lower mold for pressure control (with gap adjustment function)
7 Functional part for gap adjustment a Decomposable composition b Base material (film, etc.)
c UV shielding mask d Irradiated sheet (ultraviolet irradiation)
e Micro lens sheet

Claims (5)

  In a method for producing a resin microlens in the form of a sheet in which a large number of minute lenses are arranged, it contains an acid generator that generates an acid by the action of active energy rays or a base generator that generates a base, and further an acid or base Low boiling point generated by decomposing reaction by heating after irradiating active energy rays to a resin sheet containing a compound having a decomposable functional group that decomposes and desorbs one or more low boiling point volatile substances by reacting with A method for producing a microlens, wherein fine bubbles are formed in a resin sheet by a volatile substance so as to have a distribution in a plane direction and a thickness direction.   The method for producing a microlens according to claim 1, wherein an average bubble diameter of fine bubbles formed in the resin is 500 nm or less.   The method for producing a microlens according to claim 1 or 2, wherein a volume fraction of fine bubbles is 5 to 90% in a foamed portion formed in the resin.   4. The mask according to claim 1, wherein when irradiating the active energy ray, a mask in which the transmittance of the active energy ray continuously changes from the center of one lens forming portion to the outside is used. Microlens manufacturing method.   A microlens characterized in that a large number of fine bubbles are aggregated in a resin sheet to form a fine convex lens-shaped or concave lens-shaped foamed portion, and a large number of the foamed portions of the lens shape are arranged in a two-dimensional direction. .

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