JP2006346949A - Projection pattern forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection pattern forming method capable of easily forming a projection pattern having a large number of fine projections with high precision. <P>SOLUTION: A photo-setting resin composition 2 having fluidity is prepared and a part of this photo-setting resin composition 2 is drawn upward from the liquid surface of the photo-setting resin composition 2 at a large number of parts and irradiated with light in this state to cure the photo-setting resin composition 2. A plurality of projections are formed from a plurality of the parts of the drawn-up photo-setting resin composition 2 to form the projection pattern. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for forming a projection pattern suitable for, for example, a liquid crystal display device or an optical instrument for preventing reflection or for roughening the surface. More specifically, the present invention relates to light irradiation of a photocurable resin composition. The present invention relates to a method for forming a protrusion pattern in which a plurality of minute protrusions are formed by being cured by the above.

  Conventionally, various techniques have been proposed in which a fine protrusion pattern is formed on the surface of a member to have an optical function on the member. For example, the following Patent Document 1 discloses a polarizing plate having a moth-eye structure formed of a protrusion pattern on the surface. Here, it is shown that the transmittance can be increased regardless of the wavelength by providing a moth-eye structure on the polarizing plate surface.

  The moth-eye structure is a structure in which protrusions having a structure with a wavelength equal to or less than the wavelength of incident electromagnetic waves, for example, visible light, are densely formed. By forming such a moth-eye structure by forming such a microprojection pattern, it is said that the transmittance at various wavelengths can be increased.

  And in patent document 1, as a formation method of the surface which has such a moth-eye structure, on the surface of the protective film which consists of synthetic resins, such as a trimethyl methacrylate resin, as a protective film of a polarizing plate, the concave type according to a microprotrusion pattern is provided. A transfer method in which a stamper having a surface is pressed under heating, or a method of injection molding so as to form minute protrusions on the surface of a synthetic resin are disclosed.

Patent Document 2 below discloses a method for producing a fine concavo-convex pattern having antireflection performance. Also in the method of forming a fine concavo-convex pattern described in Patent Document 2, as with Patent Document 1, a method of transferring with a stamper is shown.
JP 2003-302532 A JP 2004-205990 A

  However, in the transfer method using a stamper or the like, it is difficult to form a large number of smaller protrusions with high accuracy. In addition, a part of the synthetic resin layer adheres to the stamper, and it tends to be difficult to peel the synthetic resin layer from the stamper.

  Similarly, in the method using the injection molding method, it is difficult to form very minute protrusions with high accuracy. In addition, even when a microprojection pattern formed by forming a large number of very small projections is formed by an injection molding method, it is difficult to reasonably peel the projection pattern after molding from the mold.

  An object of the present invention is to provide a method capable of eliminating the above-described drawbacks of the prior art and forming a microprojection pattern with high accuracy and ease.

  The method for forming a protrusion pattern according to the present invention includes a step of preparing a photocurable resin composition having fluidity, and a plurality of photocurable resin compositions from a liquid surface of the photocurable resin composition. A step of pulling upward at a portion, and a plurality of light being pulled by irradiating with light in a state where a part of the photocurable resin composition is pulled up at a plurality of portions, curing the photocurable resin composition Forming a plurality of protrusions with the curable resin composition portion.

  In a specific aspect of the method for forming a protrusion pattern according to the present invention, the step of pulling the photocurable resin composition upward at a plurality of portions adheres to the liquid surface of the photocurable resin composition at a plurality of portions. This is performed by preparing a jig to be used, bringing the jig into contact with the liquid surface of the photocurable resin composition at a plurality of portions, and then pulling up the jig.

  In another specific aspect of the method for forming a protrusion pattern according to the present invention, the jig has a plurality of protrusions on a lower surface, and the protrusions are provided at positions corresponding to the plurality of protrusions. .

  In still another specific aspect of the method for forming a protrusion pattern according to the present invention, the lower surface of the jig has a region having an affinity for the photocurable resin composition in a portion where a plurality of protrusions are provided, and a photocurable property. And the remaining region having no affinity with the resin composition.

  In still another specific aspect of the method for forming a protrusion pattern according to the present invention, the step of pulling the photocurable resin composition upward at a plurality of portions is performed on the liquid surface of the photocurable resin composition. This is done by spraying a fluid medium that has no affinity for the composition.

  In still another specific aspect of the method for forming a protrusion pattern according to the present invention, the step of pulling the photocurable resin composition upward at a plurality of portions from above the liquid level of the photocurable resin composition, It is performed by selectively sucking in the portion where the photocurable resin composition is pulled up.

  According to still another specific aspect of the method for forming a projection pattern according to the present invention, the step of pulling the photocurable resin composition upward at a plurality of portions is provided with projections in the photocurable resin composition. This is done by causing the solid member to enter between the regions where the solid member is inserted, thereby raising the photocurable resin composition on the side of the region where the solid member is inserted.

  In still another specific aspect of the method for forming a protrusion pattern according to the present invention, the step of partially pulling the photocurable resin composition upward vibrates the liquid level of the photocurable resin composition, and is standing. This is done by providing irregularities by generating waves.

  In the method for forming a protrusion pattern according to the present invention, the photocurable resin composition is not particularly limited, but preferably includes a photopolymerizable compound that is cured by photoradical polymerization and a photoradical polymerization initiator.

  In the method for forming a protrusion pattern according to the present invention, a photocurable resin composition having fluidity is prepared, and a part of the photocurable resin composition is divided into a plurality of portions from the liquid surface of the photocurable resin composition. Irradiate with light in a state of being pulled upward. The photocurable resin composition is cured by light irradiation, and a plurality of protrusions are formed by the pulled-up portions. Therefore, it is possible to easily form the fine protrusion pattern with high accuracy simply by pulling the photocurable resin composition upward at a plurality of portions. Moreover, the conventional transfer method or injection molding method using a stamper has a problem that it is difficult to peel off after the projection pattern is formed because the entire surface of the projection pattern is in surface contact with the transfer agent or the mold. In the method for forming a projection pattern of the invention, the entire surface of the projection pattern is not in contact with other members, so that peeling or the like does not become difficult.

  In the present invention, when pulling the photocurable resin composition upward at a plurality of portions, a jig that adheres to the liquid surface of the photocurable resin composition at a plurality of portions is prepared, and the jig is brought into contact with the liquid surface. When the method of pulling up the jig is used, a portion corresponding to the plurality of protruding portions can be obtained simply by bringing the plurality of portions of the jig into contact with the liquid surface of the photocurable resin composition. Can be easily formed.

  When the jig has a plurality of protrusions on the lower surface and the protrusions are provided at positions corresponding to the plurality of protrusions, the tips of the protrusions are brought into contact with the liquid surface to The photocurable resin composition can be easily pulled up at a plurality of portions simply by pulling up.

  In addition, when the lower surface of the jig has a region having affinity with the photocurable resin composition in a portion where a plurality of protrusions are to be provided, and the remaining region having no affinity, the jig In the region having an affinity for the photocurable resin composition, the photocurable resin composition adheres and hardly adheres to the remaining portion, so the lower surface of the jig is placed on the liquid surface of the photocurable resin composition. By bringing them into contact and pulling the jig upward, a part of the photocurable resin composition can be pulled up at a plurality of portions.

  Further, when the photocurable resin composition is pulled up upward at a plurality of portions by spraying a fluid medium having no affinity to the photocurable resin composition on the liquid surface of the photocurable resin composition, By spraying a fluid medium such as gas, a part of the photo-curable resin composition can be brought up in a plurality of portions in a non-contact manner. Accordingly, since the plurality of projection patterns are not in contact with other members after curing, the step of peeling the plurality of projection patterns from the other members can be omitted.

  Similarly, when the step of pulling the photocurable resin composition upward at a plurality of portions is performed by selectively suctioning from above the liquid surface of the photocurable resin composition, the same is selectively performed. By sucking, that is, the photocurable resin composition can be partially pulled upward in a non-contact manner.

  The step of pulling the photocurable resin composition upward at a plurality of portions causes the fixing member to enter between the regions where the protrusions are to be provided, and thereby the photocurable resin composition on the side of the region where the solid member is inserted When the process is performed by raising the object, it is possible to easily form a plurality of desired projections with a desired density simply by adjusting the entry position of the solid member and the shape of the tip.

  In the method in which the liquid surface of the photocurable resin composition is vibrated and a standing wave is generated to provide unevenness and the photocurable resin composition is partially pulled up, the photocurable property is obtained by a non-contact method. The resin composition can be partially pulled upward. Therefore, the process of peeling the protrusions from other members after curing can be omitted.

  In the case of using a photocurable resin composition containing a photopolymerizable compound that is cured by photoradical polymerization and a photoradical polymerization initiator, the polymerization is performed quickly, so that the light partially lifted upwards The curable resin composition can be quickly cured in that state.

  In the present invention, first, a photocurable resin composition having fluidity is prepared. This photocurable resin composition includes a wide range of resin compositions that are cured by light irradiation, and includes a photocurable resin composition that is cured by photoradical polymerization and a photocurable resin composition that is cured by photocationic polymerization. Any of them may be used. However, since the curing rate after light irradiation is high, a photocurable resin composition that cures by photoradical polymerization is preferably used.

  When the photocurable resin composition is a composition that is cured by photoradical polymerization, the photocurable resin composition comprises a photopolymerizable compound that is cured by photoradical polymerization, and a photoradical polymerization initiator. Including.

  As the photopolymerizable compound, a fine projection pattern satisfying characteristics such as transparency, strength, scratch resistance, heat resistance, water resistance, chemical resistance, adhesion to a substrate, and flexibility after polymerization and curing. Polymers that can form surface structures are preferred.

  Examples of the polymer include acrylic resin, polyester, epoxy resin, polyolefin, styrene resin, polyamide, polyimide, polyamideimide, polyurethane, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polycarbonate, melamine resin, urea resin, Examples include, but are not limited to, alkyd resins, phenol resins, cellulose resins, diallyl phthalate resins, silicone resins, polyarylate resins, polyacetal resins, and styrene-isoprene rubber.

  Among the above, acrylic resin, urethane acrylate, and polyester acrylate are particularly preferable.

  As the acrylic resin, a monomer having at least one (meth) acryloyl group in the molecule is polymerized, or two or more of such (meth) acryloyl group-containing monomers, or further vinyl monomer or allyl are added thereto. Any polymer can be used as long as it is a polymer obtained by adding a monomer having an ethylenically unsaturated bond such as a monomer and copolymerizing or graft-polymerizing it.

  In the present specification, (meth) acryloyl represents acryloyl and methacryloyl, (meth) acrylate represents acrylate and methacrylate, and (meth) acryl represents acryl and methacryl.

  Examples of the (meth) acryloyl group-containing monomer include alkyl (meth) acrylates, alkoxyalkyl (meth) acrylates, hydroxyalkyl (meth) acrylates, alkoxyalkoxyalkyl (meth) acrylates, and alkoxyalkylene glycol (meth). Monomers having a cyclic structure such as acrylates, dialkylaminoalkyl (meth) acrylates, isobornyl (meth) acrylate, monomers having a cardo structure such as bisphenoxyethanol full orange (meth) acrylate, and (meth) acryloyl-modified silicones Examples thereof include monomers having mold properties.

  As a copolymerization monomer constituting the acrylic resin, there is a curable monomer such as a monomer having an epoxy group, a thermosetting monomer such as a monomer having an oxetane compound or a methylol group, or a group causing a photodimerization reaction. If a monomer, a monomer having an isocyanate group, or the like is used, the reactivity can be imparted to the polymer.

  In addition to the use of (meth) acrylates with photocuring and thermosetting properties as the monomer for copolymerization, acrylic resins are further provided with curability by introducing functional groups into the side chains. You can also. Examples of the method for introducing a functional group include urethane modification, epoxy modification, ester modification and the like.

  Among the acrylic resins, urethane-modified acrylic resins as described in JP 2000-63459 A are preferable.

  The urethane-modified acrylic resin is, for example, made by reacting an acrylic resin having a hydroxyl group with an (meth) acrylate having an isocyanate group such as 2-isocyanatoethyl (meth) acrylate, or conversely, an acrylic resin having an isocyanate group, It can be obtained by reacting a (meth) acrylate having a hydroxyl group and introducing a (meth) acryloyl group.

  Any urethane acrylate can be used as long as it has a urethane bond and a photopolymerizable (meth) acryloyl group in the molecule. Among urethane acrylates, an isocyanate compound having two or more isocyanate groups, a compound having two or more hydroxyl groups, and a compound having one or more hydroxyl groups and one or more (meth) acryloyl groups are reacted. The urethane acrylate obtained by reacting the obtained urethane acrylate or an isocyanate compound having two or more isocyanate groups with a compound having two or more hydroxyl groups and one or more (meth) acryloyl groups is preferred.

  As urethane acrylates that are particularly preferably used, there are compounds that give a tack-free film described in JP-A-2001-329031. This compound is a reaction product of an isocyanate compound having a melting point of 40 ° C. or more, particularly a trimer of isophorone diisocyanate, and a (meth) acryl compound having a (meth) acryloyl group and capable of reacting with the isocyanate group. Can be mentioned.

  Any polyester acrylate may be used as long as it has an ester bond and a photopolymerizable (meth) acryloyl group in the molecule. Among polyester acrylates, polyester acrylates obtained by further reacting a compound having two or more hydroxyl groups or a polyester compound synthesized from a cyclic ester compound and a polybasic acid with a compound having a (meth) acryloyl group are preferred.

  Among these, urethane-modified acrylic resins and urethane acrylates are particularly preferable because they have a large number of urethane bonds and thus have high cohesive strength and can easily adjust the dynamic storage elastic modulus of the resin composition to a preferable range.

  The binder polymer is preferably a polymer component having a weight average molecular weight in terms of polystyrene of 5,000 to 500,000. When the molecular weight is less than 5,000, not only a sufficient film forming property cannot be obtained, but also blocking tends to occur when the film is wound and stored at room temperature after coating. On the other hand, when the molecular weight exceeds 500,000, it is difficult to soften, resulting in poor formability.

  Even if the molecular weight of the resin is within the above range, some resins are liquid at room temperature, and such a resin cannot be used alone as a binder polymer. For example, in the case of urethane acrylate, polyester acrylate, polyester resin, elastomer, etc., the softening temperature may be below room temperature. In that case, a resin that is liquid at normal temperature is mixed with a material that is solid at normal temperature to form an apparent solid, which can be used as a binder polymer.

  Rather, the binder polymer maintains blocking resistance by mixing a solid resin having a high softening temperature at room temperature (about 70 to 120 ° C.) and a liquid resin at room temperature, rather than using alone. Therefore, it is possible to give an appropriate thermoplasticity to improve the unevenness forming property. In particular, a combination of an acrylic resin and urethane acrylate is preferable.

  When preparing a fine concavo-convex pattern forming material having photocurability, a binder polymer having or not having a photopolymerizable functional group is selected from the binder polymers as described above, and a photopolymerizable functional group is selected as necessary. It can be prepared by blending a monomer or oligomer having a group, a photocurable component such as a photopolymerization initiator or a polymerization inhibitor, and further blending other components such as a mold release agent or an organometallic coupling agent. Below, a photocuring type component is demonstrated.

  In addition, the photopolymerizable compound in this invention shall include widely the thing which has a photopolymerizable functional group from the binder polymer mentioned above, or the monomer or oligomer which has the said photopolymerizable functional group.

  A photopolymerizable functional group is a functional group that can form a cross-linking bond between molecules by visible light or radiation containing ionizing radiation such as ultraviolet rays or electron beams, and is directly activated by light irradiation to cause a photopolymerization reaction. The polymerization reaction may be initiated and accelerated by the action of active species generated from the photopolymerization initiator when irradiated with light in the presence of a photopolymerizable functional group and a photopolymerization initiator. There may be. Examples of the photopolymerizable functional group include those having radical photopolymerization reactivity such as an ethylenic double bond, and photocationic polymerization and photoanion such as glycidyl group, alicyclic epoxy group, vinyl ether group, oxetane structure, etc. Those having polymerization reactivity can be exemplified, and among them, a radical photopolymerizable group, particularly an ethylenic double bond is preferable. As the ethylenic double bond, a (meth) acryloyl group is particularly preferable.

  The photocurable resin composition has one or more photopolymerizable functional groups (that is, monofunctional) in order to impart photocurability, decrease the viscosity of the resin composition, impart flexibility, and improve crosslink density. Or a polyfunctional monomer or oligomer may be blended.

  When utilizing a photocationic polymerization reaction, an epoxy compound, a vinyl ether compound, an oxetane compound, or the like can be used.

  If the amount of the monomer or oligomer used is too small, the strength, heat resistance, scratch resistance, water resistance, chemical resistance and adhesion to the substrate of the resulting cured resin layer may be insufficient. On the other hand, if the amount of the monomer or oligomer used is too large, it may cause an increase in surface tack, blocking, plate removal during replication, and the like. From this point of view, the monomer or oligomer is preferably blended in a proportion of 5 to 40% by weight in the total solid content of the photocurable resin composition, but the whole composition blended with the monomer or oligomer is apparently solid at room temperature. Need to be. In addition, liquid components other than a solvent are also contained in solid content of a photocurable resin composition.

  If necessary, the photocurable resin composition is blended with a photopolymerization initiator having activity with respect to the wavelength of the light source to be used. As the photopolymerization initiator, a photopolymerization initiator that generates an appropriate active species according to the difference in the reaction mode of the binder or monomer (for example, radical polymerization or cationic polymerization) is used.

  Examples of the photo radical initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, α-methylbenzoin, α-phenylbenzoin, anthraquinone, methylanthraquinone, acetophenone, 2,2-diethoxyacetophenone, 2, 2-dimethoxy-2-phenylacetone, benzyldiacetylacetophenone, benzophenone, p-chlorobenzophenone, 2-hydroxy-2-methylpropiophenone, diphenyldisulfide, tetramethylthiuram sulfide, α-chloromethylnaphthalene, anthracene, hexachlorobutadiene, Pentachlorobutadiene, Michler's ketone, 2 chlorothioxanthone, 2,4-diethylthioxanthone, benzyldimethylketer Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1,2-hydroxy-2-methyl-1 -Phenylpropan-1-one, 1 [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one and the like.

  Examples of the photocation initiator include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, aromatic phosphonium salts, mixed ligand metal salts, and the like.

  Examples of the photoanion initiator include 1,10-diaminodecane, 4,4'-trimethylenedipiperidine, carbamates and derivatives thereof, cobalt-amine complexes, aminooxyiminos, ammonium borates and the like. be able to.

  The photopolymerization initiator is preferably blended at a ratio of 0.5 to 10% by weight with respect to the total solid content of the photocurable resin composition. A photoinitiator may be used individually by 1 type and may be used in combination of 2 or more type.

  In order to improve the storage stability, a polymerization inhibitor may be blended in the photocurable resin composition of the present invention. As a polymerization inhibitor, for example, phenols such as hydroquinone, t-butylhydroquinone, catechol and hydroquinone monomethyl ether; quinones such as benzoquinone and diphenylbenzoquinone; phenothiazines; coppers and the like can be used. The polymerization inhibitor is preferably blended at a ratio of 0.1 to 10% by weight with respect to the total solid content of the photocurable resin composition.

  Next, a specific embodiment of the method for forming a projection pattern of the present invention will be described with reference to FIGS.

  1A and 1B are a front view and a front sectional view showing a method for forming a protrusion pattern according to the first embodiment of the present invention.

  In this embodiment, first, the support plate 1 shown in FIG. The support plate 1 may be an optical member that has the projection pattern formed in the present embodiment on the surface, and is peeled off from the projection pattern after the projection pattern is formed, and is used only as a support member when the projection pattern is formed. It may be a plate-like member.

  In this embodiment, the support plate 1 is made of a transparent synthetic resin plate, and by forming a projection pattern on the support plate 1, a transparent member having a fine projection pattern called a moth-eye structure on the surface. Is obtained.

  First, the above-described photocurable resin composition is applied on the flat support plate 1. The photocurable resin composition has fluidity, but the liquid level immediately after coating is flat.

  Next, the jig 3 illustrated above the support plate 1 in FIG. The jig 3 includes a plate 3a having a flat lower surface and a plurality of protrusions 3b protruding downward from the lower surface of the plate 3a. A plurality of protrusions 3b are provided on the lower surface of the plate 3a according to the number and density of minute protrusions to be formed as a protrusion pattern.

  The protrusion pattern is formed by lowering the jig 3 from above the liquid surface of the photocurable resin composition so that the tips of the plurality of protrusions 3b come into contact with the liquid surface of the photocurable resin composition having fluidity. Then, after that, the jig 3 is pulled upward after the tip of the protrusion 3b contacts the liquid surface. By this pulling up, as shown in FIG. 1 (a), the photocurable resin composition 2 having fluidity adheres to the tip of the protrusion 3b, and in a plurality of portions where the protrusion 3b is provided, it is upward. Will be raised. In this state, light for curing the photocurable resin composition 2 is immediately irradiated as indicated by an arrow. Here, since the support plate 1 is transparent and the jig 3 is also transparent, light is irradiated from both the lower surface of the support plate 1 and the upper surface of the jig 3. But the irradiation direction of light is not limited to this, You may irradiate light from the side of the part where the photocurable resin composition 2 is pulled up.

  Moreover, the light to irradiate is suitably selected according to a photocurable resin composition. Examples of such light include high energy ionizing radiation and ultraviolet rays. As the high-energy ionizing radiation source, for example, an electron beam accelerated by an accelerator such as a cockcroft accelerator, a handagraaf accelerator, a linear accelerator, a betatron, or a cyclotron is industrially most conveniently and economically used. However, radiation such as γ rays, X rays, α rays, neutron rays, proton rays emitted from radioisotopes or nuclear reactors can also be used. Examples of the ultraviolet ray source include an ultraviolet fluorescent lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a carbon arc lamp, and a solar lamp.

  Moreover, what is necessary is just to select suitably according to the composition of the photocurable resin composition 2 also about the intensity | strength of the said light to irradiate.

  Moreover, the light irradiation time should just be sufficient time for the photocurable resin composition 2 to harden | cure in the state shown to Fig.1 (a), in the state which maintained the shape shown to Fig.1 (a). It is desirable not to be too long to cure. Therefore, although depending on the composition of the photocurable resin composition 2 and the shape of the protrusions, the irradiation time may be usually about 0.01 to 10 s.

  When the photocurable resin composition 2 is cured by photoradical polymerization, the curing proceeds rapidly by the light irradiation, and the light irradiation may be stopped when the curing is completed.

  Moreover, as mentioned above, when the photocurable resin composition 2 contains a photocationic polymerizable compound and a photocationic polymerization initiator, curing proceeds by cationic polymerization even after the light irradiation is stopped. Therefore, in that case, light irradiation may be stopped before the curing is completed.

  As described above, after the photocurable resin composition 2 is cured by being irradiated with light while being pulled upward at a plurality of portions, the jig 3 is separated from the cured product of the photocurable resin composition 2. do it. In this way, as shown in FIG. 1B, a projection pattern 2 b provided with a plurality of projections 2 a can be formed on the support plate 1. Therefore, a moth-eye structure can be formed on the surface of the transparent support plate 1.

  In the method for producing the projection pattern of the present embodiment, as described above, the plurality of projections 2a are formed by irradiating the photocurable resin composition 2 with light and curing. Therefore, minute protrusions can be formed easily and quickly. In addition, in the transfer method using a conventional stamper or the like, it may be difficult to peel off the transfer agent from the protrusion pattern when a minute protrusion is formed. It is not necessary to peel off the members that are in contact with each other. Therefore, even when the dimensions of the protrusions 2a are reduced and the density between the protrusions 2a is high, the protrusion pattern can be formed easily and quickly.

  FIG. 2 is a schematic front view for explaining a method of forming a protrusion pattern according to a modification of the first embodiment.

  In the first embodiment, on the flat support plate 1, the jig 3 having a plurality of protrusions 3b arranged in parallel on the lower surface is lowered from the upper surface of the photocurable resin composition layer, as shown in FIG. Thus, you may use the roller 13 by which the some protrusion 13a was provided in the outer peripheral surface. Here, a photocurable resin composition layer is formed using a coating roll 14 on a long support plate 11 to be conveyed. After the photocurable resin composition 12 having fluidity is applied onto the long support belt 11, the photocurable resin composition 12 is conveyed together with the support belt 11 in the direction of the arrow shown in the drawing.

  Each protrusion 13a of the roll 13 provided with a plurality of protrusions 13a comes into contact with the liquid surface of the photocurable resin composition 12 and rotates in the direction of the arrow shown in the figure, and the photocurable resin composition 12 supports it. As the belt 11 is transported in the length direction, the portion of the photocurable resin composition that comes into contact with the tip of the protrusion 13a is pulled upward. Therefore, in this state, by irradiating light as indicated by an arrow A, the photocurable resin composition can be cured and protrusions can be formed. In other words, by arranging the plurality of protrusions 13 a in the paper-back direction of FIG. 2, the plurality of protrusions can be formed in a direction orthogonal to the conveying direction of the support belt 11. Therefore, similarly to the case of the first embodiment, the micro-projection pattern can be easily formed with high accuracy by using the photocurable resin composition.

  FIGS. 3A and 3B are schematic partial cutaway front sectional views for explaining still another embodiment of the method for forming a projection pattern of the present invention.

  In FIG. 3A, the step of partially lifting the photocurable resin composition 2 upward is performed using the fluid medium spraying means 21. That is, the fluid medium spraying means 21 is formed by, for example, a high-pressure gas injection nozzle, and by spraying a gas from the fluid medium spraying means 21 as indicated by an arrow B, the photocurable resin composition having fluidity is provided. The thickness of a part of the object 2 is reduced. That is, the photocurable resin composition 2 is moved from the portion where the gas is sprayed to the periphery thereof, and the thickness of the photocurable resin composition 2 is relatively increased in the periphery. Therefore, such a gas spraying region can be selected, and the photocurable resin composition can be pulled upward in a region other than the region where the gas is sprayed. Therefore, if light is irradiated while maintaining this state, protrusions can be formed by curing the photocurable resin composition 2 at the portion where the photocurable resin composition 2 is pulled upward.

  The fluid medium is not limited to gas but may be liquid, and various gases such as air and nitrogen gas can be used as the gas. The gas may be a mixed gas. Further, when the liquid is sprayed, the liquid may be sprayed as a large number of fine droplets with a spray gun or the like.

  On the other hand, in the embodiment shown in FIG. 3 (b), as indicated by an arrow C, the liquid surface of the fluid curable resin composition 2 is partially sucked so that light is absorbed in the sucked portion. The curable resin composition 2 is pulled upward. In this method, by selectively sucking the photocurable resin composition 2 in a plurality of portions, the photocurable resin composition 2 can be pulled upward in the sucked portion. Therefore, if the photocurable resin composition 2 is irradiated with light while being sucked and cured, the projection pattern having a plurality of projections is photocured as in the case of the first embodiment described above. The resin composition 2 can be easily and highly accurately formed by utilizing the curing by light irradiation.

  FIG. 4 is a partially cutaway enlarged front sectional view for explaining still another embodiment of the method for forming a projection pattern of the present invention. Here, the solid photocurable resin composition moving member 31 is caused to enter the region other than the region where the protrusions are provided in the photocurable resin composition 2 having fluidity. Thereby, the photocurable resin composition is moved to the surrounding area. As a result, in the surrounding area, the photocurable resin composition is swelled as shown in the drawing and is pulled upward. Here, the front end of the photocurable resin composition moving member 31 has a curved shape as shown in the drawing, and the entry speed of the photocurable resin composition moving member 31 depends on the curvature of the curved shape. Depending on the size and size, the photocurable resin composition can be pulled up around the periphery in a desired form. Therefore, by adjusting these factors, it is possible to realize a state where the photocurable resin composition is pulled up to a desired height at a plurality of portions. Therefore, if light is irradiated in that state, the projection pattern can be formed quickly and with high accuracy, as in the first embodiment described above.

  FIG. 5 is a schematic front view for explaining still another modification of the method for forming a projection pattern of the present invention. Here, a jig 41 having a region 41a having an affinity for the photocurable resin composition in a portion where a protrusion is to be formed on the lower surface and a region 41b having no affinity in the remaining portion is used. By bringing the lower surface of the jig 41 into contact with the liquid surface of the photocurable resin composition 2 and pulling it up, as shown in FIG. 5, the photocurable resin composition is partially pulled up at a plurality of portions. be able to. That is, the lower surface of the jig 41 is selectively partitioned into a region 41a having an affinity for the photocurable resin composition and a region 41b having no affinity, thereby making the region 41a having an affinity a first region. It can be made to function similarly to the protrusion of the embodiment.

  The preferable viscosity of the photocurable resin composition is within a range of about 1 to 500,000 cps at the temperature at which the photo-curing resin composition is pulled up in order to make it easy and reliable to pull up partially and maintain the pulled-up state. Is desirable. In addition, the temperature which raises is about room temperature of about 25 degreeC normally. If it is less than 1 cps, it is difficult to maintain the state where it is pulled upward, and if it exceeds 500,000 cps, it may be difficult to pull it upward using a jig or the like.

  Next, specific examples will be described.

  As a photocurable resin composition, 67 g of urethane acrylate (manufactured by Nippon Synthetic Chemical Co., Ltd., trade name: Gooselac UV-7500B) and 33 g of 2-hydroxypropyl acrylate are mixed, dissolved by heating, and 0.2 g of BHT is added thereto. A photocurable resin compound solution was prepared. To this photocurable compound solution, 1.0 g of methylphenylglyoxylate was added as a radical photopolymerization initiator. This photopolymerization initiator has a molar extinction coefficient of 10 or more in the wavelength range of 280 to 398 nm.

  Furthermore, 0.3 g of 2- (5-methyl-2-hydroxyphenyl) benzotriazole was added as an ultraviolet absorber to the composition prepared as described above to obtain a photocurable resin composition.

  The photocurable resin composition obtained as described above had a viscosity at 25 ° C. of 100 cps and had fluidity at room temperature.

  As the support plate 1 shown in FIG. 1, the photocurable resin composition was coated on a Toyobo film made of PET (polyethylene terephthalate) and having a thickness of 80 μm so as to have a thickness of 100 μm. Thereafter, a jig 3 made of SUS304 was prepared. In addition, the pitch of the some protrusion 3b provided in the lower surface of the jig | tool 3 was 100 nm, and the downward protrusion length of the protrusion 3b was 20 nm.

After approaching the liquid surface of the photocurable resin composition applied as described above from the lower surface side of the jig 3, the tips of the plurality of protrusions 3b are brought into contact with the liquid surface, and then the tips of the protrusions 3b are moved. The photocurable resin composition 2 was pulled up to a height of 100 nm upward from the initial liquid level. Thereafter, while maintaining this state, an ultrahigh pressure mercury lamp was used to irradiate with ultraviolet rays so as to give an irradiation dose of 100 mW / cm ² . The irradiation time was 1 second.

  In this way, the photocurable resin composition was cured to form a microprojection pattern shown in FIG. The average reflectance of the protrusion pattern thus obtained was determined as follows.

  Measurement of average reflectance: First, the prepared antireflection film was cut into a 5 cm square, and the back surface was roughened with # 400 sandpaper, and then painted with black ink to a size of about 2 cm to prepare a sample. With respect to this back-treated sample, the reflectance spectrum at 5 ° incidence with a wavelength of 200 to 780 nm was measured using a spectrophotometer (manufactured by Shimadzu Corporation, model “UV-3101PC”). The visibility-corrected average reflectance was read from the measured reflectance spectrum.

  As a result, the average reflectance was 0.4%, and it was confirmed that a microprojection pattern having a moth-eye structure can be formed.

  Therefore, as is clear from the above embodiments, according to the present invention, it can be seen that a pattern having a plurality of minute protrusions can be formed quickly and easily. According to the experiment by the present inventor, it has been confirmed that protrusions having dimensions from the nm order to the cm order can be formed with high accuracy at various pitches.

(A) And (b) is the front view and front sectional drawing for demonstrating the formation method of the protrusion pattern in one Embodiment of this invention. The schematic front view for demonstrating the modification of the formation method of the projection pattern of this invention. (A) And (b) is each partial notch enlarged sectional drawing for demonstrating other embodiment of the formation method of the projection pattern of this invention. The partial notch expansion front sectional view for demonstrating another embodiment of the formation method of the projection pattern of this invention. The typical front view for demonstrating the formation method of the protrusion pattern of other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Support plate 2 ... Photocurable resin composition 2a ... Protrusion 2b ... Hardened | cured material 3 ... Jig 3a ... Plate 3b ... Protrusion 11 ... Support belt 12 ... Photocurable resin composition 13 ... Roll 13a ... Protrusion 14 ... Coating roll 21 ... Flowable medium spraying device 31 ... Photocurable resin composition moving member 41 ... Jig 41a, 41b ... Area

Claims (9)

Preparing a photocurable resin composition having fluidity; and
A step of pulling upward some of the photocurable resin composition from the liquid surface of the photocurable resin composition in a plurality of portions;
In a state where a part of the photocurable resin composition is pulled up at a plurality of portions, light is irradiated to cure the photocurable resin composition, and a plurality of the photocurable resin composition portions are pulled up to a plurality of portions. Forming a protrusion of the protrusion pattern.   The step of pulling up the photocurable resin composition upward at a plurality of portions prepares a jig that adheres to the liquid surface of the photocurable resin composition at a plurality of portions, The method for forming a projection pattern according to claim 1, wherein the protrusion pattern is formed by pulling up the jig after contacting the liquid level of the photocurable resin composition.   The method for forming a projection pattern according to claim 2, wherein the jig has a plurality of protrusions on a lower surface, and the protrusions are provided at positions corresponding to the plurality of protrusions.   The lower surface of the jig has a region having affinity with the photocurable resin composition in a portion where a plurality of protrusions are provided, and a remaining region having no affinity with the photocurable resin composition. 3. A method for forming a projection pattern according to 2.   The step of pulling the photocurable resin composition upward in a plurality of portions is performed by spraying a fluid medium having no affinity for the photocurable resin composition on the liquid surface of the photocurable resin composition. The method for forming a protrusion pattern according to claim 1.   The step of pulling the photocurable resin composition upward at a plurality of portions is performed by selectively sucking the photocurable resin composition from above the liquid surface of the photocurable resin composition at the portion where the photocurable resin composition is pulled up. The method for forming a protrusion pattern according to claim 1.   The step of pulling up the photocurable resin composition upward at a plurality of portions causes the solid member to enter between the regions where the protrusions are provided in the photocurable resin composition, thereby causing the solid member to enter. The method for forming a projection pattern according to claim 1, wherein the method is performed by raising a photocurable resin composition on a side of a region where the protrusion is present.   The step of partially pulling up the photocurable resin composition upward is performed by vibrating the liquid surface of the photocurable resin composition and generating a standing wave to provide irregularities. A method for forming a projection pattern according to the above. The method for forming a projection pattern according to claim 1, wherein the photocurable resin composition includes a photopolymerizable compound that is cured by photoradical polymerization and a photoradical polymerization initiator.

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