JP2015138242A - Irregular structure, irregular structure manufacturing method, optical component, and optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an irregular structure exhibiting high optical performance, an irregular structure manufacturing method capable of efficiently manufacturing the irregular structure, and an optical component and an optical device each including the irregular structure and high in reliability.SOLUTION: A microlens array (irregular structure) 1, which is a quadrangular plate-like member in a plan view, comprises: a flat portion 11 that has a relatively small surface height; and a plurality of convex portions 12 that protrudes from this flat portion 11 and that has a relatively large surface height. The flat portion 11 can be, therefore, regarded as a concave portion smaller in surface height than the convex portions 12 with reference to the convex portions 12. Each convex portion 12 is a region formed by partially irradiating a layer 3 containing polymers 21 and monomers 22 higher in index of refraction than the polymers 21 with active radiations R, thereby reducing a volume of the polymers 21, and thereby relatively protruding a non-irradiated area 32. A refraction index distribution N of each convex portion 12 includes a distribution in which the index of refraction gradually increases from an outer edge of the convex portion 12 toward a center.

Description

  The present invention relates to an uneven structure, a method for manufacturing an uneven structure, an optical component, and an optical device.

  A solid-state imaging device such as a CCD (Charge Coupled Device) includes a large number of light receiving units ranging from several million pixels to several tens of millions of pixels, and the number of pixels is likely to further increase in the future. However, since the size of the solid-state image sensor is limited, the area occupied by one light receiving portion naturally becomes smaller as the number of pixels increases. As a result, there is a concern that the light receiving sensitivity of the solid-state imaging device may be further reduced or noise may be further increased.

  Therefore, an effective aperture ratio is improved by mounting a microlens group on the solid-state image sensor. Thereby, the improvement of the sensitivity of a solid-state image sensor, improvement of S / N ratio, etc. can be aimed at.

  The microlens group is an aggregate of a large number of microlenses arranged in accordance with the position of the light receiving unit, and is generally composed of a glass material or a resin material. Since the size of the microlens is very small and the positional accuracy of the arrangement is important, in general, precision processing techniques such as a photolithography method and an etching method are used for manufacturing such a microlens group. It becomes.

  For example, in Patent Document 1, a base film forming step of forming a base film using a lens material, a resist patterning step of forming a resist pattern formed of a plurality of circular convex surfaces on the base film by a photolithography method, and a resist Manufacturing a lens array having a reflow process for deforming a circular convex surface into a spherical lens shape by subjecting the pattern to a thermal melting process, and an etch-back process for transferring the resist pattern deformed into a spherical lens shape to a base film A method is disclosed.

  However, both the photolithography method and the etching method require a large and expensive apparatus and a large amount of auxiliary materials. For this reason, it is not easy to reduce the manufacturing cost of the microlens group. Moreover, there is a possibility that the material may be deteriorated or contaminated by contact with a secondary material such as a photoresist or an etching solution.

  On the other hand, as the number of pixels increases, the inter-lens distance of the microlens group becomes smaller. For this reason, a phenomenon called crosstalk in which light interferes between adjacent lenses is likely to occur, resulting in a decrease in image quality of the solid-state image sensor.

JP 2008-52004 A

  An object of the present invention is to provide a concavo-convex structure body having high optical performance, a method for manufacturing the concavo-convex structure body that efficiently manufactures the concavo-convex structure body, a highly reliable optical component and an optical device including the concavo-convex structure body. is there.

Such an object is achieved by the present inventions (1) to (10) below.
(1) A concavo-convex structure having a convex portion whose surface partially protrudes,
The projection is partially irradiated with actinic radiation to a layer containing a polymer and a monomer having a refractive index lower than that of the polymer, so that the volume occupied by the polymer is reduced and the irradiation region is recessed. A non-irradiated area is a part that protrudes relatively with it,
The convex-concave structure is characterized in that the refractive index distribution of the convex portion includes a distribution in which the refractive index gradually increases from the outer edge side to the central side of the convex portion.

  (2) The concavo-convex structure according to (1), including a monomer concentration distribution in which the concentration of the monomer gradually decreases from the outer edge side to the center side of the convex portion.

  (3) Said convex part has the part with the highest protrusion height of the surface, and the part from which the protrusion height is gradually decreasing toward the circumference | surroundings from said (1) or (2) The uneven structure according to 1.

  (4) The concavo-convex structure according to (3), wherein the refractive index distribution of the convex portion is a distribution in which the refractive index is highest in a portion where the protrusion height is highest.

  (5) The unevenness according to any one of (1) to (4), wherein the refractive index distribution of the uneven structure includes a minimum value of the refractive index located adjacent to the outside of the convex portion. Structure.

  (6) The concavo-convex structure according to any one of (1) to (5), wherein the convex portion is formed by partially projecting a front surface and a back surface facing the front surface.

(7) having a step of partially irradiating actinic radiation to a layer containing a polymer and a monomer having a refractive index lower than that of the polymer;
A convex part formed by relatively projecting the surface of the non-irradiated region by utilizing the fact that the volume of the polymer decreases in the irradiated region irradiated with the active radiation and the surface of the irradiated region is partially recessed. A process for producing a concavo-convex structure, characterized in that

  (8) The method for producing a concavo-convex structure according to (7), wherein the actinic radiation is irradiated so that the integrated light amount distribution is uniform with respect to the irradiation region.

(9) An optical component comprising the uneven structure according to any one of (1) to (6) above.
(10) An optical device comprising the optical component according to (9).

According to the present invention, a concavo-convex structure with high optical performance can be obtained.
Moreover, according to this invention, the said uneven structure can be manufactured efficiently.

  Moreover, according to this invention, a reliable optical component and optical apparatus provided with the said uneven structure body are obtained.

It is a top view which shows the microlens array to which 1st Embodiment of the optical component of this invention is applied, the AA sectional view taken on this plan view, and the graph which shows the refractive index distribution in this cross section. It is each the elements on larger scale of FIG.1 (b), (c). It is sectional drawing for demonstrating the manufacturing method of the micro lens array to which 1st Embodiment of the manufacturing method of the uneven structure of this invention is applied. It is sectional drawing for demonstrating the microlens array to which 2nd Embodiment of the optical component of this invention is applied, and its manufacturing method. It is sectional drawing which shows the structure of the pixel periphery of the CCD image sensor to which embodiment of the optical apparatus of this invention is applied.

  Hereinafter, the concavo-convex structure, the method for manufacturing the concavo-convex structure, the optical component, and the optical device of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

<< First Embodiment >>
<Microlens array>
First, the microlens array (microlens group) to which the first embodiment of the optical component of the present invention (uneven structure of the present invention) is applied will be described.

  FIG. 1 is a plan view showing a microlens array to which the first embodiment of the optical component of the present invention is applied, a cross-sectional view taken along line AA of this plan view, and a graph showing a refractive index distribution in this cross-section. 2 is a partially enlarged view of each of FIGS. 1 (b) and 1 (c). In the following description, the upper surface in FIGS. 1B and 2D is referred to as “front surface”, and the lower surface is referred to as “back surface”.

  A microlens array (optical component of the present invention, concavo-convex structure of the present invention) 1 shown in FIG. 1A is a plate-like body having a square shape in plan view, and a flat portion 11 having a relatively low surface height. And a plurality of convex portions 12 protruding from the flat portion 11 and having a relatively high surface height. Therefore, the flat portion 11 can be regarded as a concave portion having a lower surface height than the convex portion 12 when the convex portion 12 is used as a reference.

  The planar view shape of the convex portion 12, that is, the planar view shape of the boundary line between the convex portion 12 and the flat portion 11 is circular. The plurality of convex portions 12 are regularly arranged at predetermined intervals. On the other hand, the back surface 13 of the microlens array 1 is a flat surface.

  Since the convex portion 12 has a curved convex surface, the convex portion 12 functions as a so-called convex lens, and can refract light transmitted between the front and back surfaces of the microlens array 1 in a predetermined direction. Thereby, the microlens array 1 has a convex lens effect such as focusing on a predetermined focal length.

  The term “plate-like body” refers to a concept that includes a relatively thick material, a relatively thin sheet shape, a film shape, and the like that are not substantially flexible. Further, the arrangement pattern of the plurality of convex portions 12 is not limited to that shown in FIG. 1, and may be any pattern such as a regular one or an irregular one.

  As shown in FIG. 1B, the convex portion 12 has a surface height that gradually increases from the apex 121, which is the highest surface height, toward the periphery (left and right in FIG. 1B). And a gradually decreasing portion 122 which is a decreasing portion. Such a surface shape provides a light collecting effect peculiar to a convex lens.

  The difference between the protrusion height h1 of the convex portion 12, that is, the average surface height h2 of the flat portion 11 from the back surface 13 and the surface height h3 of the top 121 is the average surface height of the flat portion 11 (flat portion 11 Average thickness) h2 or the like, and is not particularly limited, but is preferably about 0.1 to 100 μm, and more preferably about 0.5 to 80 μm. Thereby, the convex part 12 has sufficient condensing effect.

  On the other hand, the average surface height (average thickness of the flat part 11) h2 of the flat part 11 from the back surface 13 is appropriately set according to the mechanical strength of the microlens array 1 and is not particularly limited. It is preferable that it is about -200 micrometers, and it is more preferable that it is about 1-150 micrometers. As a result, the microlens array 1 has sufficient shape followability when laminated with other members and has sufficient durability against tearing and the like.

  Further, the microlens array 1 has a nonuniform refractive index distribution, and has a bias corresponding to the position of the convex portion 12 and the like. FIG. 1C is a graph in which the horizontal axis indicates the position in the AA line cross-sectional view of the microlens array 1 and the vertical axis indicates the refractive index in this cross section. The refractive index distribution N of the convex portion 12 shown in FIG. 1C includes a refractive index change in which the refractive index gradually increases from the outer edge side of the convex portion 12 toward the center side. By having such a refractive index distribution N, not only the light condensing effect by the surface shape but also the light condensing effect by the refractive index distribution N is superimposed on the convex portion 12. That is, in the convex portion 12, light can be refracted and condensed by the convex lens shape, but the condensing power (refractive power) increases as the refractive index increases. Thus, if the refractive index is high in the convex part 12, the light collection effect can be enhanced accordingly. As a result, it is possible to obtain the microlens array 1 having a feature that, for example, the focal length is short although the thickness is small.

  Further, in the microlens array 1 shown in FIG. 1, the refractive index in the refractive index distribution N is the highest corresponding to the top 121 of the convex portion 12. Therefore, in the microlens array 1, the surface height gradually decreases from the top 121 to the outer edge of the convex portion 12, and the refractive index gradually decreases from the top 121 to the outer edge of the convex portion 12. doing. For this reason, when both the surface shape and the refractive index distribution N draw a perpendicular line passing through the top 121 and orthogonal to the back surface 13, the convex part 12 has a line-symmetric relationship with the perpendicular line. I can say that. In such a convex portion 12, the refractive index distribution N contributes to the enhancement of the light collecting effect, and functions substantially as a complex optical system such as an aspherical lens without complicating the surface shape, for example. It will be possible. As a result, it is possible to easily obtain a microlens array 1 having high optical performance that can correct various aberrations such as spherical aberration.

  In the microlens array 1 shown in FIG. 1, the refractive index is the highest corresponding to the top 121, while the refractive index gradually decreases toward the outer edge of the convex portion 12. For this reason, the light incident on the convex portion 12 is confined in the convex portion 12 based on the refractive index distribution in the convex portion 12. In particular, since the refractive index is gradually changed, the light confinement effect on the optical axis becomes stronger as in the so-called graded index type optical fiber. As a result, the light condensing effect of the convex portions 12 is further strengthened, and for example, it is suppressed that the light collected between the adjacent convex portions 12 interferes with each other. Such an effect contributes to suppressing the occurrence of so-called crosstalk when, for example, the microlens array 1 is incorporated in a solid-state imaging device. Moreover, since the high light condensing effect is acquired without complicating the surface shape of the convex part 12 by the light confinement effect mentioned above, the shape design of the convex part 12 can be made easy. As a result, cost reduction in manufacturing the microlens array 1 can be achieved.

  The shape of the convex portion 12 is not particularly limited as long as the surface height is partially higher than that of the flat portion 11. For example, the convex portion 12 is located between the top 121 and the flat portion 11. The gradually decreasing rate of the surface height in the gradually decreasing portion 122 may be in any range. That is, the gradual decrease rate of the gradual decrease part 122 may be very large, and the top 121 may be stepped (rapidly) higher than the flat part 11, and conversely, the gradual decrease rate is very small and the top 121 And the surface of the flat part 11 may be connected with a gentle inclination.

  In addition, the planar view shape of the convex portion 12 is not limited to the perfect circle shown in FIG. 1A, for example, a polygon such as a quadrangle, a hexagon, and an octagon, another circle such as an ellipse, an ellipse, It may be a rhombus, trapezoid, parallelogram, star, needle, or the like. Furthermore, the planar view shape of the convex part 12 may be a pattern in which these arbitrary shapes and arbitrary sizes are combined.

  The shape of the refractive index distribution N may be any shape as long as it includes a refractive index change in which the refractive index gradually increases from the outer edge side to the center side of the convex portion 12. That is, the change rate of the refractive index in the refractive index distribution N may be very large, and the refractive index of the convex portion 12 may be increased stepwise (abruptly) with respect to the flat portion. The refractive index may be very small, and the refractive index may gradually decrease from the top 121 to the outer edge of the protrusion 12.

  In the refractive index distribution N, the refractive index difference d1 between the maximum value of the refractive index at the top 121 of the convex portion 12 and the maximum value of the refractive index at the flat portion 11 is about 0.001 to 0.10. Preferably, it is about 0.003-0.04. By setting the refractive index difference d1 within the above range, the light incident on the convex portion 12 is more reliably confined in the convex portion 12, and the influence of the refractive index distribution N in the microlens array 1 becomes larger than necessary. Can be suppressed. That is, when the refractive index difference d1 is less than the lower limit value, depending on the surface shape of the convex portion 12, there is a possibility that the light confinement effect in the convex portion 12 may not be sufficiently obtained, and the refractive index difference d1 exceeds the upper limit value. When exceeding, depending on the surface shape of the convex part 12, the influence of the refractive index distribution N may become obvious and optical design of the microlens array 1 may be difficult.

  In addition, as shown in FIGS. 1 to 3, the refractive index distribution N is near the boundary between the convex portion 12 and the flat portion 11, that is, on the side opposite to the top 121 of the gradually decreasing portion 122 (outside the convex portion 12). It may be located adjacent to each other and have a local minimum value whose refractive index is locally smaller than that of the periphery. Hereinafter, the refractive index distribution near the minimum value is referred to as “low refractive index portion NL”. By providing such a low refractive index portion NL, the refractive index difference between the top 121 of the convex portion 12 and the outside of the convex portion 12 can be further expanded. Thereby, the effect of confining light in the convex portion 12 is further strengthened. Note that the minimum value of the low refractive index portion NL is smaller than the refractive index of the convex portion 12 and the refractive index of the flat portion 11.

  In this case, the refractive index difference d2 between the minimum value of the refractive index in the low refractive index portion NL and the maximum value of the refractive index in the flat portion 11 is preferably about 3 to 150% of the above-described refractive index difference d1. More preferably, it is about 5 to 100%, more preferably about 10 to 80%. Thereby, the effect of confining light in the convex part 12 is necessary and sufficient, and the convex part 12 with less variation in the effect can be stably manufactured.

  As shown in FIG. 2D, the constituent material of the microlens array 1 includes a polymer 21 serving as a matrix and a monomer 22 that is dispersed in the polymer 21 and has a refractive index lower than that of the polymer 21. And in the convex part 12, compared with the flat part 11, the density | concentration of the monomer 22 is low. As described above, since the concentration of the monomer 22 having a lower refractive index than that of the polymer 21 is low, the refractive index of the convex portion 12 is higher than that of the flat portion 11.

  In the microlens array 1 having such a structure, the surface shape is formed due to the volume reduction of the polymer 21 and the refractive index distribution is formed due to the concentration difference of the monomer 22 dispersed in the polymer 21. Therefore, it can be said that it is a substantially monolithic structure. Therefore, the microlens array 1 can be handled as an integral member regardless of the surface shape of the convex portion 12, and can be manufactured as a lens-attached sheet capable of a roll-to-roll process suitable for mass production. it can.

  Further, in the microlens array 1, as shown in FIG. 2D, the concentration of the monomer 22 gradually increases from the outer edge of the convex portion 12 toward the top 121, and accordingly, FIG. As shown, the refractive index also changes continuously. Such a concentration distribution of the monomer 22 is useful from the viewpoint of the continuity of the structure of the microlens array 1. That is, according to such a concentration distribution of the monomer 22, it is difficult to generate a structural boundary, so that it is possible to suppress uneven mechanical properties such as bending rigidity, and to perform a bending operation with, for example, a uniform curvature radius. It is possible to obtain a microlens array 1 with good handleability.

  The concavo-convex structure of the present invention is an optical component other than the microlens array 1 as described above, such as a color filter substrate, a light diffusion plate, a light diffusion film, an antireflection film, a polarizing plate, a polarizing film, and a viewing angle improvement. It can be applied to optical parts such as films, optical compensation films, diffraction grating films, and moth-eye structures.

  Furthermore, the concavo-convex structure of the present invention can also be applied to things other than optical components, such as an antistatic film, a fingerprint adhesion preventing film, a water-repellent (liquid-repellent) structure, a low friction sheet, and the like.

<Method for manufacturing microlens array>
Next, a method for manufacturing a microlens array to which the first embodiment of the method for manufacturing an uneven structure according to the present invention is applied will be described.

  FIG. 3 is a cross-sectional view for explaining a manufacturing method of a microlens array to which the first embodiment of the manufacturing method of a concavo-convex structure of the present invention is applied, and a graph showing a refractive index distribution in this cross section. In the following description, the upper surface in FIG. 3 is referred to as “front surface”, and the lower surface is referred to as “back surface”.

  In the method of manufacturing the microlens array 1, first, the layer 3 including the polymer 21 and the monomer 22 having a refractive index lower than that of the polymer 21 is prepared on the substrate 30. Next, the layer 3 is partially irradiated with actinic radiation R. Thereby, in the layer 3, the volume of the polymer 21 in the irradiation region 31 is reduced. As a result, the irradiation region 31 is recessed and the non-irradiation region 32 protrudes relatively, so that the convex portion 12 is formed corresponding to the non-irradiation region 32. Further, the monomer 22 moves from the non-irradiation region 32 toward the irradiation region 31 with the polymerization reaction of the monomer 22 in the irradiation region 31. As a result, the refractive index of the convex portion 12 is relatively increased. Hereinafter, each process will be described sequentially.

  [1] First, a layer 3 including a polymer 21 and a monomer 22 having a refractive index lower than that of the polymer 21 is prepared on the substrate 30. In this layer 3, as shown in FIG. 3A, the monomer 22 and the like are uniformly dispersed in the matrix made of the polymer 21.

  As the substrate 30, for example, a silicon substrate, a quartz substrate, a glass substrate, a polyethylene terephthalate (PET) substrate, a polyimide substrate, or the like is used.

  Further, the surface of the substrate 30 may have an uneven shape. Examples of the irregular shape include an antireflection structure having a large number of concave portions and convex portions, and a spherical and aspherical structure having a lens shape. By using such a substrate 30, the uneven shape is transferred to the layer 3, and the shape of the microlens array 1 finally obtained can be further enhanced.

(polymer)
Examples of the polymer 21 include acrylic resins, methacrylic resins, polycarbonates, polystyrenes, cyclic ether resins such as epoxy resins and oxetane resins, polyamides, polyimides, polybenzoxazoles, polysilanes, polysilazanes, silicone resins, Fluorine resin, polyurethane, polyolefin resin, polybutadiene, polyisoprene, polychloroprene, polyester such as PET and PBT, polyethylene succinate, polysulfone, polyether, and cyclic olefins such as benzocyclobutene resin and norbornene resin These resins can be used, and one or more of these can be used in combination (as a polymer alloy, polymer blend (mixture), copolymer, etc.).

  Among these, the polymer 21 mainly includes at least one selected from the group consisting of (meth) acrylic resins, epoxy resins, silicone resins, polyimide resins, fluorine resins, and polyolefin resins. Those that do are preferred. By using the polymer 21 mainly composed of these resins, the microlens array 1 having excellent optical characteristics such as light transmittance and excellent weather resistance and mechanical characteristics can be obtained. In the microlens array 1, not only the refractive index distribution N is formed by the concentration distribution of the monomer 22, but also the refractive index distribution N is formed by the structural change of the polymer 21. In order to realize such behavior, the chemical structure of the polymer 21 is designed to have a main chain and a structure having at least one of a leaving group and a polymerizable group that are released from the main chain by actinic radiation R described later. do it. Thus, the leaving group can be removed from the main chain by irradiation with the actinic radiation R, and as a result, the refractive index of the polymer 21 can be changed. Then, coupled with the refractive index change due to the concentration distribution of the monomer 22, the amount of change in the refractive index can be controlled more finely. In addition, the polymer 21 mainly composed of these resins can be obtained by setting the film forming conditions of the layer 3 and the irradiation conditions of the actinic radiation R as appropriate so that the leaving group is released as the leaving group is released. Only a decrease in volume can be manifested. Moreover, a polymeric group reacts and it can also implement | achieve volume reduction. With these volume reductions, recesses having a sufficient depth can be formed, and various surface shapes can be formed on the layer 3 by appropriately setting the arrangement and size of the recesses. .

  Examples of such a leaving group include those having at least one of an —O— structure, an —Si—aryl structure, and an —O—Si— structure in a molecular structure. Such a leaving group is easily detached from the main chain by the action of actinic radiation R, but cleavage is further promoted by utilizing the action of a cation.

  Among these, the leaving group that causes a decrease in the refractive index of the polymer 21 by leaving is preferably at least one of a -Si-diphenyl structure and a -O-Si-diphenyl structure.

  Moreover, as another leaving group, the substituent which has an acetophenone structure at the terminal is mentioned, for example. This leaving group is easily detached from the main chain by the action of actinic radiation R, but cleavage is further promoted by utilizing the action of free radicals.

  The amount of the leaving group is not particularly limited, but is preferably 10 to 80% by mass and more preferably 20 to 60% by mass with respect to the total mass of the polymer 21. When the amount of the leaving group is within the above range, a polymer having an excellent refractive index modulation function (an effect of changing the refractive index difference) can be obtained, and mechanical characteristics of the formed microlens array 1 can be improved. Can be achieved.

  Such a polymer having a leaving group can be easily obtained by polymerizing a raw material monomer and a monomer having a leaving group introduced into the raw material monomer.

  Examples of the polymerizable group include an epoxy group, an acrylic group, an oxetane group, and a maleimide group.

  As the polymer 21, a polymer having excellent light transmittance and further excellent heat resistance is preferably used. In addition, the polymer 21 has compatibility with the monomer 22 described later, and among them, the monomer 22 can react (polymerization reaction or crosslinking reaction) as described later, and even after the monomer 22 has reacted. Those having high transparency are preferably used.

  Here, “having compatibility” may be a state where the monomer 22 is at least mixed and irradiated with actinic radiation R so that the radiation does not have an influence such as reflection due to phase separation.

Hereinafter, the polymer 21 will be further described in detail.
((Acrylic polymer))
(Meth) acrylic polymers are acrylic monomers such as acrylic acid and acrylic esters, methacrylic monomers such as methacrylic acid and methacrylic esters, or derivatives thereof (for example, alkoxy derivatives, caprolactone derivatives, etc.) Is a polymer (including resin and rubber) obtained by polymerizing this raw material monomer.

  Therefore, as the (meth) acrylic polymer, a homopolymer obtained by polymerizing one of the raw material monomers, a copolymer obtained by polymerizing two or more different raw material monomers, the raw material monomer and another raw material monomer Examples thereof include copolymers formed by polymerization.

  Examples of such raw material monomers include monofunctional (meth) acrylate, bifunctional (meth) acrylate, trifunctional or higher polyfunctional (meth) acrylate, and the like.

  Examples of monofunctional (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and s-butyl. (Meth) acrylate, t-butyl (meth) acrylate, butoxyethyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, octyl heptyl (meth) ) Acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate Rate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-chloro-2- Aliphatic (meth) acrylates such as hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, dicyclopentanyl (meth) Acrylate, dicyclopentenyl (meth) acrylate, isobornyl (meth) acrylate, 3-methyl-3-oxetanylmethyl (meth) acrylate, 1-adamantyl (meth) acrylate Cycloaliphatic (meth) acrylates such as salt, phenyl (meth) acrylate, nonylphenyl (meth) acrylate, p-cumylphenyl (meth) acrylate, o-biphenyl (meth) acrylate, 1-naphthyl (meth) acrylate, 2-naphthyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3- (o-phenylphenoxy) propyl (meth) acrylate, 2-hydroxy-3 -(1-naphthoxy) propyl (meth) acrylate, aromatic (meth) acrylate such as 2-hydroxy-3- (2-naphthoxy) propyl (meth) acrylate, 2-tetrahydrofurfuryl (meth) acrylate, N- (Meth) acryloyloxye And heterocyclic (meth) acrylates such as tilhexahydrophthalimide and 2- (meth) acryloyloxyethyl-N-carbazole.

  Examples of the bifunctional (meth) acrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and polyethylene glycol di ( (Meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,3 -Butanediol di (meth) acrylate, 2-methyl-1,3-propanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, ne Pentyl glycol di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 2-butyl-2-ethyl-1,3-propanediol Fats such as di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, glycerin di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate Alicyclic (meth) acrylate, cyclohexanedimethanol (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, hydrogenated bisphenol A di (meth) acrylate, hydrogenated bisphenol F di (meth) acrylate ( (Meth) acrylate, bispheno Such as aromatic A (meth) acrylate such as di- (meth) acrylate, bisphenol F di (meth) acrylate, bisphenol AF di (meth) acrylate, fluorene type di (meth) acrylate, and isocyanuric acid di (meth) acrylate And heterocyclic (meth) acrylates.

  Examples of the trifunctional or higher polyfunctional (meth) acrylates include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, and pentaerythritol tetra (meth) acrylate. And aliphatic (meth) acrylates such as dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and heterocyclic (meth) acrylates such as isocyanuric acid tri (meth) acrylate.

  In addition, although it does not specifically limit as another raw material monomer superposed | polymerized with the said raw material monomer, For example, an acrylonitrile etc. are mentioned, When acrylic acid (methacrylic acid) type monomer is selected as said raw material monomer, these are superposed | polymerized. By doing so, an acrylic rubber is obtained.

  Examples of the raw material monomer include MMA monomer (manufactured by Kuraray or Mitsubishi Rayon), acrylate monomer (manufactured by Daicel Cytec), Blemmer (manufactured by NOF), acrylate monomer (manufactured by Nippon Shokubai), photocurability. Monomers / oligomers (manufactured by Shin-Nakamura Chemical Co., Ltd.), etc.

The weight average molecular weight of the (meth) acrylic polymer is not particularly limited, but is preferably about 1 × 10 ^{4 to} 3 × 10 ^{5 in} terms of polystyrene, and preferably about 3 × 10 ⁴ to 2 × 10 ^5. More preferred. By using such a (meth) acrylic polymer having a weight average molecular weight, the compatibility with the monomer 22 described later can be improved, and the mechanical characteristics of the microlens array 1 can be improved. As a result, the monomer 22 can be moved in the polymer 21 at a necessary and sufficient speed and distance, and the target refractive index distribution N can be reliably formed.

  Furthermore, a (meth) acrylic polymer having an epoxy group can also be used.

  When obtaining this (meth) acrylic polymer, examples of the raw material monomer include glycidyl (meth) acrylate, α-ethylglycidyl (meth) acrylate, α-propylglycidyl (meth) acrylate, and α-butylglycidyl (meth) acrylate. 2-methylglycidyl (meth) acrylate, 2-ethylglycidyl (meth) acrylate, 2-propylglycidyl (meth) acrylate, 3,4-epoxybutyl (meth) acrylate, 3,4-epoxyheptyl (meth) acrylate, α-ethyl-6,7-epoxyheptyl (meth) acrylate, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, 3,4-epoxycyclohexylmethyl (meth) acryl , 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylpropyl (meth) acrylate, 3,4-epoxycyclohexylbutyl (meth) acrylate, etc. Can be used.

  Further, as the raw material monomer, for example, EBECRYL (manufactured by Daicel Cytec), Denacol acrylate (manufactured by Nagase ChemteX), Neopol (manufactured by Nippon Iupika) and the like can be used. Furthermore, as the (meth) acrylic polymer having an epoxy group, for example, Blemmer (manufactured by NOF Corporation) can be used.

  A maleimide-modified acrylic polymer can also be used. As this polymer, for example, Aron Tac (manufactured by Toagosei) or the like can be used, and as a raw material monomer, for example, Aronix (manufactured by Toagosei) or the like can be used.

  Furthermore, a fluorine-containing (meth) acrylic polymer can also be used. As a raw material monomer for obtaining this polymer, for example, METHACRYLATES CAS No. 1799-84-4 (2- (perfluorobutyl) ethyl methacrylate) manufactured by Daikin Industries Ltd., Unimatec Cheminox and the like can be used.

  In addition, as (meth) acrylic polymer, Sumipex MHF (manufactured by Sumitomo Chemical), silicone graft (meth) acrylic polymer, Cymac US-352 (manufactured by Toagosei), UV curable (meth) acrylic polymer 8KX-018C (manufactured by Taisei Fine Chemical Co., Ltd.) can be used.

  In addition, as raw material monomers, terminal acrylic polyether, Denacol acrylate DA-931 (manufactured by Nagase ChemteX), terminal methacryl silicone oil, BY167-152C (manufactured by Toray Dow Corning), aqueous acrylate, RD-180 (Manufactured by Mutual Chemical Industries), ABE-300 as bisphenol A diacrylate, A-BPEF (above, Shin-Nakamura Chemical Co., Ltd.) as full orange acrylate, Miramer HR-3700 (manufactured by Toyo Chemicals), benzyl ( A (meth) acrylate (made by Hitachi Chemical Co., Ltd.) etc. can be used.

((Epoxy polymer))
Epoxy polymers include norbornene-based epoxy monomers, silicon-containing epoxy monomers, alicyclic epoxy monomers, bisphenol-type epoxy monomers, fluorinated epoxy monomers, aliphatic epoxy monomers, naphthalene ring-containing epoxy monomers, aromatic ring-containing epoxy monomers, etc. A polymer (including resin and rubber) obtained by polymerizing the raw material monomer using a monomer or a derivative thereof as the raw material monomer.

  Therefore, as an epoxy polymer, a homopolymer obtained by polymerizing one of the above raw material monomers, a copolymer obtained by polymerizing two or more different raw material monomers, and the above raw material monomer and another raw material monomer are polymerized. And the like.

  Among such raw material monomers, examples of the norbornene epoxy monomer include those represented by the following formula (1).

  In addition, the compound represented by Formula (1) is epoxy norbornene, For example, ProNBAS EpNB can be used as such a compound. In addition, HP-7200HHH manufactured by DIC can be used as the dicyclopentadiene type epoxy monomer.

  Moreover, as a silicon containing epoxy monomer, what is represented by following formula (2) or Formula (3) is mentioned, for example.

  In addition, the compound represented by Formula (2) is (gamma) -glycidoxy propyl trimethoxysilane, As this compound, Toray Dow Corning Z-6040 can be used, for example. Moreover, the compound represented by Formula (3) is 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and as this compound, for example, E0327 manufactured by Tokyo Chemical Industry can be used. In addition, SF8413, BY16-839, and SF8421 manufactured by Toray Dow Corning can be used.

  Furthermore, as an alicyclic epoxy monomer, what is represented by following formula (4)-Formula (6) is mentioned, for example.

  The compound represented by the formula (4) is 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate, and as this compound, for example, Celoxide 2021P manufactured by Daicel Chemical Industries, Ltd. is used. can do. Further, the compound represented by the formula (5) is 1,2-epoxy-4-vinylcyclohexane. As this compound, for example, Celoxide 2000 manufactured by Daicel Chemical Industries, Ltd. can be used. Further, the compound represented by the formula (6) is 1,2: 8,9 diepoxy limonene, and as this compound, for example, (Celoxide 3000 manufactured by Daicel Chemical Industries, Ltd.) can be used. In addition, Celoxide 2081 manufactured by Daicel Chemical Industries, Ltd. can also be used.

  Examples of the bisphenol-type epoxy monomer include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, and those represented by the following formula (7).

In addition, as a compound represented by Formula (7), specifically, for example, bisphenoxyethanol fluorenediglycidyl ether (in Formula (7), n = 1, and R _{1 to} R ₆ are all hydrogen atoms) Bisphenol fluorenediglycidyl ether (in formula (7), n = 0, R _{1 to} R ₆ are all hydrogen atoms), and the like. In addition, YS-128S and YD-020G manufactured by Nippon Steel Chemical Co., Ltd. can be used as bis A type epoxy monomers, and ST-3000 and ST-4000D manufactured by Nippon Steel Chemical Co., Ltd. can be used as hydrogenated bis A type epoxy monomers. .

  Furthermore, as a fluorinated epoxy monomer, what is represented by following formula (8) is mentioned, for example. In addition, Daikin Industries 'EPOXIDES CAS No.74328-56-6 (1,6-bis (2', 3'-epoxypropyl) -perfluoro-n-hexane), EPOXIDES CAS No.791-22-0 (1, 4-bis (2 ′, 3′-epoxypropyl) -perfluoro-n-butane) can also be used.

  Moreover, as an aliphatic epoxy monomer, what is represented by following formula (9) is mentioned, for example. In addition, Denasel EX-850L and Denacol EX-216L manufactured by Nagase ChemteX can be used as the polyfunctional aliphatic epoxy monomer.

  Furthermore, as a naphthalene ring containing epoxy monomer, what is represented by following formula (10) is mentioned, for example.

［式（７）中、Ｒ_１〜Ｒ_４は、それぞれ独立して、水素原子または炭素数１〜６のアルキル基である。また、Ｒ_５、Ｒ_６は、それぞれ独立して、水素原子またはメチル基である。さらに、各ｎは、それぞれ独立して、０〜１０の整数を表わす。］

[In Formula (7), R < ₁ > -R < ₄ > is a hydrogen atom or a C1-C6 alkyl group each independently. R ₅ and R ₆ are each independently a hydrogen atom or a methyl group. Further, each n independently represents an integer of 0 to 10. ]

［式（８）中、ｎは、２〜１０の整数を表わす。］

[In Formula (8), n represents the integer of 2-10. ]

［式（９）中、ｎは、２〜１０の整数を表わす。］

[In formula (9), n represents an integer of 2 to 10. ]

［式（１０）中、Ｒは、水素原子、炭素数１〜４のアルキル基、またはフェニル基を表わす。］

[In Formula (10), R represents a hydrogen atom, a C1-C4 alkyl group, or a phenyl group. ]

  In addition to the above, as an epoxy polymer or raw material monomer, Epicoat (manufactured by Japan Epoxy Resin), phenoxy resin YP series, novolac type epoxy resin YDCN series (above, manufactured by Nippon Steel Chemical Co., Ltd.), Ogsol EG (Osaka Gas) Chemical), Biphenyl type epoxy resin YX-4000H (Mitsubishi Chemical), Rica Resin (Nippon Nippon Chemical Co., Ltd.), Silicone modified epoxy (Shin-Etsu Chemical or Toray Dow Corning), Denacol (Nagase ChemteX), Fluorine Epoxy (made by Daikin Industries), ARUFON UG-4000, 4035, 4040 (made by Toagosei), Aron Oxetane OXT-213, 221, 211 (made by Toagosei) and the like can be used.

  In addition, when making an epoxy-type polymer into the copolymer formed by superposing | polymerizing the said raw material monomer and another raw material monomer, if it is a thing different from the said raw material monomer as another raw material monomer, it will not specifically limit.

The weight average molecular weight of the epoxy polymer is not particularly limited, but is preferably about 1 × 10 ^{4 to} 3 × 10 ^{5 in} terms of polystyrene, and more preferably about 3 × 10 ⁴ to 2 × 10 ⁵ . By using such an epoxy polymer having a weight average molecular weight, compatibility with the monomer 22 described later can be improved, and mechanical characteristics of the microlens array 1 can be improved. As a result, the monomer 22 can be moved in the polymer 21 at a necessary and sufficient speed and distance, and the target refractive index distribution N can be reliably formed.

((Silicone polymer))
The silicone polymer is a polymer (including resin and rubber) obtained by polymerizing (hydrolyzing / condensing or condensing) the raw material monomer using organoalkoxysilane or a derivative thereof as a raw material monomer.

  Therefore, as a silicone polymer (polyorganosiloxane), a homopolymer obtained by polymerizing one of the above raw material monomers, a copolymer obtained by polymerizing two or more different raw material monomers, the above raw material monomer and other raw material monomers And a copolymer obtained by polymerizing and the like.

  The organoalkoxysilane used as a raw material monomer (silicone monomer) is not particularly limited, and examples thereof include those represented by the following formula (11).

［式（１１）中、Ｒ^１、Ｒ^３は、それぞれ独立して、一価の有機基である。また、Ｒ^２は、アルキル基またはアルコキシアルキル基である。さらに、ｍは、０または１であり、ｎは、０〜３の整数を表わす。］

[In Formula (11), R ¹ and R ³ are each independently a monovalent organic group. R ² is an alkyl group or an alkoxyalkyl group. Furthermore, m is 0 or 1, and n represents an integer of 0 to 3. ]

In formula (11), R ¹ and R ³ (monovalent organic group) are each independently an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group, vinyl Group, alkenyl group such as allyl group, aryl group such as phenyl group and tolyl group, aralkyl group such as naphthyl group and phenethyl group, halogenated alkyl group, halogenated aryl group and carbon atoms in these organic groups Examples thereof include a nitrogen atom, an oxygen atom, a silicon atom, a sulfur atom, a phosphorus atom, or an atomic group containing these atoms.

R ² is specifically an alkyl group such as a methyl group, an ethyl group, a propyl group, or a butyl group, a methoxymethyl group, an ethoxymethoxy group, a propoxymethoxy group, a methoxyethoxy group, an ethoxyethoxy group, or a propoxyethoxy group. And an alkoxyalkyl group such as a butoxyethoxy group.

  Specific examples of the organoalkoxysilane represented by the above formula (11) include isopropyltrimethoxysilane, neopentyltrimethoxysilane, allyltrimethoxysilane, 4-vinylphenyltrimethoxysilane, and trimethylsilylmethyl. Trimethoxysilane, isobutyltriethoxysilane, ethynyltrimethoxysilane, diethynyldimethoxysilane, 4-vinylphenyltriethoxysilane, trimethylsilylmethyltriethoxysilane, isopropyltripropoxysilane, cyclopentyltriisopropoxysilane, neopentylriboxysilane, Isopropylmethyldimethoxysilane, methylneopentyldimethoxysilane, cyclohexylmethyldimethoxysilane, methylcyclopentyldimeth Sisilane, allylmethyldimethoxysilane, (4-chlorophenyl) methyldimethoxysilane, ethylpropyldimethoxysilane, ethylisopentyldimethoxysilane, ethylneopentyldimethoxysilane, ethylcyclopentyldimethoxysilane, phenylethyldimethoxysilane, ethyl-3,3,3 -Trifluoropropyldimethoxysilane, butylpropyldimethoxysilane, sec-butylpropyldimethoxysilane, pentylpropyldimethoxysilane, hexylpropyldimethoxysilane, 3-chloropropylpropyldimethoxysilane, 3-bromopropylpropyldimethoxysilane, isopropyl-sec-butyl Dimethoxysilane, isopropylcyclopentyldimethoxysilane, isopropylvinyldimethoxy Run, cyclopentylisobutyldimethoxysilane, dihexyldimethoxysilane, dicyclopentyldimethoxysilane, bis (trimethylsilylmethyl) dimethoxysilane, 3,3,3-trifluoropropylhexyldimethoxysilane, sec-butylmethyldiethoxysilane, ethylpropyldiethoxysilane , Ethyl-tert-butyldiethoxysilane, dipropyldiethoxysilane, diisopropyldiethoxysilane, diisopropylbutylethoxysilane, dicyclopentyldiethoxysilane, 4-methoxyphenylvinyldiethoxysilane, isobutyldimethylmethoxysilane, tert-butyldimethyl Methoxysilane, (4-chlorophenyl) dimethylmethoxysilane, dimethyl-2-thienylmethoxysilane, Propylmethoxysilane, tributylmethoxysilane, isobutyldimethylethoxysilane, allyldimethylethoxysilane, triethylethoxysilane, phenyldiethylethoxysilane, dipropylisobutylethoxysilane, diphenylmethylethoxysilane, allyldimethylpropoxysilane, triethylpropoxysilane, diphenylmethyl Butoxysilane, 1,4-bis (methyldimethoxysilyl) phenylene, 2-aminoethylaminomethyltrimethoxysilane, 3-aminopropyldimethylethoxysilane, 2- (2-aminoethylthioethyl) triethoxysilane, β- ( 3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, and the like.

  When the silicone polymer is a copolymer obtained by polymerizing the raw material monomer (organoalkoxysilane) and another raw material monomer, the other raw material monomer may be of a different type from the raw material monomer, There is no particular limitation.

Although the weight average molecular weight of a silicone type polymer is not specifically limited, It is preferable that it is about 1 * 10 < ⁴ > -3 * 10 < ⁵ > in polystyrene conversion, and it is more preferable that it is about 3 * 10 < ⁴ > -2 * 10 < ⁵ >. By using a silicone-based polymer having such a weight average molecular weight, compatibility with the monomer 22 described later can be improved, and mechanical characteristics of the microlens array 1 can be improved. As a result, the monomer 22 can be moved in the polymer 21 at a necessary and sufficient speed and distance, and the target refractive index distribution N can be reliably formed.

((Polyimide polymer))
The polyimide polymer is a polymer containing a polyimide (oligomer) obtained by heating and curing (imidizing) a polyamic acid obtained by reacting a tetracarboxylic acid anhydride and a diamine.

  Therefore, as the polyimide polymer, a homopolymer obtained by polymerizing one kind of the above polyimide, a block copolymer obtained by polymerizing two or more kinds of the above polyimide, a block copolymer obtained by polymerizing the above polyimide and another oligomer, etc. Is mentioned.

  Although it does not specifically limit as a tetracarboxylic anhydride and diamine used in order to obtain such a polyimide, For example, the following are mentioned.

  That is, examples of the tetracarboxylic acid anhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, and 2,2-bis (2,3-dicarboxyphenyl). ) Propane dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone Those having no fluorine atom in the molecule such as acid dianhydride, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 4,4-bis (3,4- Dicarboxytrifluorophenoxy) tetrafluorobenzene dianhydride, 1,4-bis (3,4-dicarboxytrifluorophenoxy) tetrafluorobenzene dianhydride, Fluoromethyl) bimellitic dianhydride, di (trifluoromethyl) pyromellitic dianhydride, di (heptafluoropropyl) pyromellitic dianhydride containing fluorine atoms in the molecule Of these, one or two or more of these can be used in combination.

  Examples of the diamine include m-phenylenediamine, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, bis (3-aminophenyl) sulfide, and (3-aminophenyl) (4-aminophenyl). Sulfide, bis (3-aminophenyl) sulfoxide, (3-aminophenyl) (4-aminophenyl) sulfoxide, bis (4-aminophenyl) sulfone, (3-aminophenyl) (4-aminophenyl) sulfone, 3, 4′-diaminobenzophenone, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4′-bis (3-aminophenoxy) biphenyl, bis [4- (4-Aminophenoxy) phenyl] ketone, bis [4- (3-aminophenyl) Noxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfoxide, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, 4, 4'-diamino-5,5'-diphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 3,4'-diamino-4,5'-dibiphenoxybenzophenone, 3,3'-diamino-4 -No fluorine atom in the molecule such as biphenoxybenzophenone, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 2-trifluoromethyl-4,4'-diamino Diphenyl ether, 2′-trifluoromethyl-3,4′-diaminodiphenyl ether, 2,2-bi (3-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 1,3-bis (3-aminophenoxy) -4-trifluoromethylbenzene, 1,3-bis (3- Amino-5-trifluoromethylphenoxy) benzene, 1,3-bis (3-amino-5-trifluoromethylphenoxy) -5-trifluoromethylbenzene, 1,4-bis (4-amino-2-trifluoro) Methylphenoxy) benzene, 2,2-bis [4- (3-aminophenoxy) phenyl) -1,1,1,3,3,3-hexafluoropropane containing a fluorine atom in the molecule, etc. These can be used, and one or more of these can be used in combination.

  In addition, when the polyimide-based polymer is a block copolymer obtained by polymerizing the polyimide (oligomer) and another oligomer, the other oligomer is not particularly limited as long as it is of a type different from the polyimide, For example, at least one of (meth) acrylic oligomers, epoxy oligomers, and silicone oligomers (organosiloxane oligomers) can be used.

The weight average molecular weight of the polyimide-based polymer is not particularly limited, is preferably 1 × ¹⁰ 4 ~1 × ¹⁰ about ⁶ in terms of polystyrene, and more preferably 2 × ¹⁰ 5 ~4 × ¹⁰ about ^5. By using a polyimide-based polymer having such a weight average molecular weight, compatibility with the monomer 22 described later can be improved, and mechanical characteristics of the microlens array 1 can be improved. As a result, the monomer 22 can be moved in the polymer 21 at a necessary and sufficient speed and distance, and the target refractive index distribution N can be reliably formed.

((Fluoropolymer))
The fluorine-based polymer is a polymer containing a fluorine atom in its molecular structure. In the present invention, at least one of an aliphatic ring structure, an imide ring structure, a triazine ring structure, a benzoxazole structure, and an aromatic ring structure is used. It is preferably used that has one kind of ring structure and contains a fluorine atom in the structure. Among these, a polymer having an aliphatic ring structure as a main chain is particularly preferable.

  A polymer having an aliphatic ring structure as a main chain (hereinafter sometimes referred to as “fluorinated aliphatic ring structure polymer”) is a monomer having a ring structure containing a fluorine atom, a fluorine atom and two or more fluorine atoms. A monomer having a polymerizable unsaturated bond can be used as a raw material monomer to polymerize this raw material monomer.

  Therefore, the fluorine-containing aliphatic ring structure polymer includes a homopolymer obtained by polymerizing one of the raw material monomers, a copolymer obtained by polymerizing two or more different raw material monomers, the raw material monomer and other raw material monomers. And the like.

  In the present specification, the fluorine-containing aliphatic ring structure polymer is mainly composed of a plurality of aliphatic ring structures, and one or more carbon atoms constituting this aliphatic ring structure. A fluorine atom or an atomic group containing a fluorine atom is bonded.

  Specific examples of such a fluorinated alicyclic polymer include those having structural units (repeating units) as listed in the following formulas (12) to (16) in the main chain.

［上記各式中、ｌは０〜５、ｍは０〜４、ｎは０〜１、ｌ＋ｍ＋ｎは１〜６、ｏ、ｐ、ｑは、それぞれ独立して、０〜５、ｏ＋ｐ＋ｑは１〜６であり、Ｒ^１、Ｒ^２およびＲ^３は、それぞれ独立して、Ｆ、Ｃｌ、ＣＦ_３、Ｃ_２Ｆ_５、Ｃ_３Ｆ_７またはＯＣＦ_３であり、Ｘ^１およびＸ^２は、それぞれ独立して、ＦまたはＣｌである。］

[In the above formulas, l is 0-5, m is 0-4, n is 0-1, 1 + m + n is 1-6, o, p, q are each independently 0-5, o + p + q is 1-6. 6, R ¹ , R ² and R ³ are each independently F, Cl, CF ₃ , C ₂ F ₅ , C ₃ F ₇ or OCF ₃ , and X ¹ and X ² are each independently F or Cl. ]

  In order to obtain the fluorine-containing aliphatic ring structure polymer having such a configuration, examples of the monomer (monomer) having a ring structure containing a fluorine atom include perfluoro (2,2-dimethyl-1,3-dioxole). , Perfluoro (2-methyl-1,3-dioxole), perfluoro (2-ethyl-2propyl-1,3-dioxole), perfluoro (2,2-dimethyl-4methyl-1,3-dioxole), etc. Those having perfluorodioxoles in which a fluorine-substituted alkyl group such as a fluorine atom, a trifluoromethyl group, a pentafluoroethyl group or a heptafluoropropyl group is bonded to a dioxole ring member carbon, or perfluoro (4-methyl-2 -Methylene-1,3-dioxolane), perfluoro (2-methyl-1,4-dioxin) and the like Such as those comprising a fluorine alicyclic structure and the like, can be used singly or in combination of two or more of them.

  Moreover, as a monomer (monomer) provided with a fluorine atom and two or more polymerizable unsaturated bonds, for example, perfluoro (3-oxa-1,5-hexadiene), perfluoro (3-oxa-1,6- Heptadiene), perfluoro (4-methyl-3-oxa-1,6-heptadiene), perfluoro (4-chloro-3-oxa-1,6-heptadiene), perfluoro (4-methoxy-3-oxa-1,6) -Heptadiene), perfluoro (5-methyl-3-oxa-1,6-heptadiene), and the like, and one or more of these can be used in combination.

  In addition, the fluorine-containing aliphatic ring structure polymer uses, as a raw material monomer, both a monomer having a ring structure containing a fluorine atom and a monomer having a fluorine atom and two or more polymerizable unsaturated bonds, These can also be obtained by copolymerizing them.

  Further, when the fluorine-containing aliphatic ring structure polymer is a copolymer obtained by polymerizing the above raw material monomer and another raw material monomer, examples of the other raw material monomer include tetrafluoroethylene, chlorotrifluoroethylene, perfluoro A radical polymerizable monomer such as (methyl vinyl ether) can be used.

Although the weight average molecular weight of a fluorine-type polymer is not specifically limited, It is preferable that it is about 1 * 10 < ⁴ > -3 * 10 < ⁵ > in polystyrene conversion, and it is more preferable that it is about 3 * 10 < ⁴ > -2 * 10 < ⁵ >. By using such a fluorine-based polymer having a weight average molecular weight, compatibility with the monomer 22 described later can be improved, and mechanical characteristics of the microlens array 1 can be improved. As a result, the monomer 22 can be moved in the polymer 21 at a necessary and sufficient speed and distance, and the target refractive index distribution N can be reliably formed.

((Polyolefin polymer))
Examples of the polyolefin polymer include ethylene, propylene, 1-butene, cis-2-butene, trans-2-butene, isobutene, 1-pentene, 2-pentene, 2-methyl-1-butene, and 3-methyl-1. -Monoolefin monomers such as butene, 2,3-dimethyl-2-butene, 1-butene, 1-hexene, 1-octene, 1-nonene, 1-decene, allene, methylallene, butadiene, 2,3 -Polymers (including resins and rubbers) obtained by polymerizing raw material monomers using diene monomers such as dimethylbutadiene, 1,3-pentadiene, 1,4-pentadiene, chloroprene and 1,5-hexadiene. .)

  The polyolefin-based polymer includes a homopolymer obtained by polymerizing one of the raw material monomers, a copolymer obtained by mixing two or more different raw material monomers, and the raw material monomer and another raw material monomer. And the like.

  Further, other raw material monomers to be polymerized with the above raw material monomers are not particularly limited. For example, styrene, α-methyl styrene, o-methyl styrene, p-methyl styrene, m-methyl styrene, o-ethyl styrene, p -Aromatic vinyl monomers such as t-butylstyrene, chlorostyrene, chloromethylstyrene, bromostyrene, (meth) acrylonitrile, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth ) Vinyl monomers such as butyl acrylate, allyl (meth) acrylate, N-phenylmaleimide, N-methylmaleimide, butyl acetate, vinyl acetate, isopropenyl acetate, vinyl chloride and vinyl ether.

  Examples of the polymer obtained by polymerizing the above raw material monomers include polystyrene, styrene-butadiene copolymer, vinyl acetate or a hydrolyzate thereof, polyvinyl alcohol, polyacetal, polybutyral, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer. Examples include coalescence.

  On the other hand, the polyolefin polymer may be a cyclic olefin polymer such as a norbornene polymer or a benzocyclobutene polymer. As the cyclic olefin polymer, for example, those described in JP 2010-090328 A are used. The cyclic olefin polymer may be either one having a single repeating unit (homopolymer) or two having two or more repeating units (copolymer). Specific examples include a homopolymer of hexyl norbornene, phenyl Examples include a homopolymer of ethyl norbornene, a homopolymer of benzyl norbornene, a copolymer of hexyl norbornene and phenylethyl norbornene, and a copolymer of hexyl norbornene and benzyl norbornene.

  Moreover, as another raw material monomer, the monomer which has a chemical structure which one part is photoisomerized or photodimerized by irradiation of actinic radiation R may be sufficient. In a polyolefin-based polymer having such a chemical structure, irradiation with actinic radiation R causes photoisomerization or photodimerization, and its refractive index changes. As a result, coupled with the refractive index change due to the concentration distribution of the monomer 22, the amount of change in the refractive index can be controlled more finely. Photoisomerization is a phenomenon in which cis-trans isomerization, photo-Fries rearrangement, and decarboxylation are caused by irradiation with actinic radiation, and photodimerization is a phenomenon in which bonds are formed between adjacent double bonds. It is.

  Examples of such a chemical structure for photoisomerization or photodimerization include N = N group such as azobenzene group, azonaphthalene group, aromatic heterocyclic azo group, bisazo group, formazan group, maleimide group, indene group, C = C group such as coumarin group, cinnamate group, polyene group, stilbene group, stilbazole group, stilbazolium group, cinnamoyl group, hemithioindigo group, chalcone group, C═N group such as aromatic Schiff base, aromatic hydrazone structure , C═O groups such as benzophenone group and anthraquinone group, ester groups such as allyl ester group, acylphenol structure, etc., and at least one of them is used. In particular, at least one of an azobenzene group, a maleimide group, a coumarin group, a cinnamoyl group, and an indene group is preferably used.

  Examples of the compound having the above chemical structure include, for example, Imilex (manufactured by Nippon Shokubai), aliphatic bismaleimide (manufactured by DMI), Aronix (manufactured by Toagosei), bismaleimides (manufactured by Kay Aikasei), methylcinnamate (Inoue Fragrance Factory), 2-methoxyhexyl paramethoxycinnamate and the like.

(monomer)
The monomer (photopolymerizable monomer) 22 reacts in the irradiation region 31 to generate a reaction product by irradiation with actinic radiation R described later. At the same time, the monomer 22 moves and causes a refractive index difference between the irradiated region 31 and the non-irradiated region 32 of the layer 3.

  The reaction product of the monomer 22 includes a polymer (polymer) formed by polymerizing the monomer 22 in the polymer 21, a crosslinked structure in which the monomer 22 is crosslinked with each other, and the monomer 22 is branched from the polymer 21. And at least one of the branched structures polymerized as described above.

  By the way, the refractive index difference generated between the irradiated region 31 and the non-irradiated region 32 is generated based on the difference between the refractive index of the polymer 21 and the refractive index of the monomer 22, so that the monomer 22 has the refractive index of the polymer 21. It is selected in consideration of the magnitude relationship with. In the present invention, a monomer 22 having a refractive index lower than that of the polymer 21 is selected and used.

  As the monomer 22, a monomer having compatibility with the polymer 21 and having a refractive index difference with the polymer 21 of 0.01 or more is preferably used.

  Such a monomer 22 is not particularly limited as long as it is a compound having a polymerizable site in the molecular structure, and examples thereof include acrylic acid (methacrylic acid) monomers, epoxy monomers, oxetane monomers, and norbornene monomers. A monomer, a vinyl ether monomer, a styrene monomer, a photodimerization monomer and the like can be mentioned, and one or more of these can be used in combination.

  By using the same type of monomer 22 as the monomer for producing the polymer 21 among these monomers 22, the monomer 22 can be more uniformly dispersed in the polymer 21, so that the surface shape after the movement of the monomer 22 is reached. It is easy to control the refractive index distribution N.

  Further, unsaturated hydrocarbons are particularly preferably used as the polymerizable portion. A compound containing an unsaturated hydrocarbon tends to cause a polymerization reaction such as radical polymerization or cationic polymerization, and is suitable as the monomer 22 used in the present invention.

  Here, as the acrylic acid (methacrylic acid) monomer and the epoxy monomer, the same monomers as those cited as the raw material of the polymer 21 can be used.

  Further, since the ring opening of the cyclic ether group is likely to occur, a monomer or oligomer having a cyclic ether group such as an oxetanyl group and an epoxy group can react rapidly. Therefore, the time for forming the microlens array 1 can be shortened by using such a monomer.

  The molecular weight (weight average molecular weight) of the monomer having a cyclic ether group or the molecular weight (weight average molecular weight) of the oligomer is preferably 100 or more and 400 or less, respectively.

  Examples of vinyl ether monomers include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-hexyl vinyl ether, and n-octyl. Examples thereof include alkyl vinyl ethers such as vinyl ether, n-dodecyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, and cycloalkyl vinyl ethers, and one or more of these can be used in combination.

  Moreover, as a styrene-type monomer, styrene, divinylbenzene, etc. are mentioned, for example, These 1 type or 2 types can be used in combination.

  Further, examples of the photodimerization monomer include monomers having a chemical structure that can be photodimerized as described above, and specifically, 4,4′-diphenylmethane bismaleimide, bis- (3-ethyl-5-methyl-4-methyl). Maleimidophenyl) methane, 2,2′-bis- [4- (4-maleimidophenoxy) phenyl] propane and the like can be mentioned, and one or two of these can be used in combination.

  In addition, the combination of these monomers 22 and the polymer 21 mentioned above is not specifically limited, Any combination may be sufficient.

  Furthermore, as the monomer 22, the various monomers described above, that is, monomers such as acrylic acid (methacrylic acid) monomer, epoxy monomer, oxetane monomer, norbornene monomer, vinyl ether monomer, styrene monomer, photodimerization monomer, Two or more types may be used in combination, regardless of the same type or non-same type. Among these combinations, it is preferable to use two or more of a monomer having an oxetanyl group, an oligomer having an oxetanyl group, a monomer having an epoxy group, and an oligomer having an epoxy group in combination.

  Monomers having an oxetanyl group and oligomers having an oxetanyl group have a slow initiation reaction but a fast growth reaction. On the other hand, a monomer having an epoxy group and an oligomer having an epoxy group have a fast initiation reaction for initiating polymerization, but have a slow growth reaction. Therefore, when the actinic radiation R is irradiated by using a monomer having an oxetanyl group, an oligomer having an oxetanyl group, a monomer having an epoxy group, and an oligomer having an epoxy group, the irradiated region 31 and the non-irradiated region 32 are used. The difference in refractive index can be reliably generated.

  As the monomer having an oxetanyl group, for example, Aron oxetane (manufactured by Toagosei Co., Ltd.) can be used.

  Further, at least a part of the monomer 22 may be oligomerized as described above.

  Examples of the monomer and oligomer having an oxetanyl group and the monomer and oligomer having an epoxy group include those described in JP 2010-090328 A.

  The addition amount of these monomers 22 is preferably 1 part by mass or more and 70 parts by mass or less, and more preferably 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the polymer 21. Thereby, a necessary and sufficient refractive index difference can be formed, and the irradiation region 31 can be recessed to a necessary and sufficient depth. Therefore, when the addition amount of the monomer 22 is lower than the lower limit, depending on the composition of the polymer 21 and the monomer 22, there is a possibility that a sufficient refractive index difference may not be obtained, and the optical performance of the manufactured microlens array 1 is low. There is a risk. On the other hand, when the addition amount of the monomer 22 exceeds the upper limit, depending on the composition of the polymer 21 or the monomer 22, the content of the polymer 21 is relatively decreased, and the height of the convex portion 12 becomes insufficient. Further, the diversity of the surface shape is reduced, and the monomer 22 and the reaction product thereof are immediately saturated in the irradiation region 31, so that the moving speed of the monomer 22 may be reduced and the shape of the convex portion 12 may vary.

(Polymerization initiator)
Moreover, the layer 3 may contain the polymerization initiator as needed. In addition, when the reactivity of the monomer 22 is high, the reaction may proceed even without a polymerization initiator.

  The polymerization initiator acts on the monomer 22 with irradiation of actinic radiation and promotes the reaction of the monomer 22.

  The polymerization initiator to be used is appropriately selected according to the type of polymerization reaction or crosslinking reaction of the monomer 22. For example, radical polymerization initiators are preferably used exclusively for acrylic acid (methacrylic acid) monomers and styrene monomers, and cationic polymerization initiators are preferably used exclusively for epoxy monomers, oxetane monomers, and vinyl ether monomers.

  Examples of the radical polymerization initiator include benzophenones and acetophenones. Specifically, Irgacure 651, Irgacure 184 (above, manufactured by BASF Japan) and the like can be mentioned.

  On the other hand, examples of the cationic polymerization initiator include a Lewis acid generating type such as a diazonium salt, and a Bronsted acid generating type such as an iodonium salt and a sulfonium salt. Specifically, Adekaoptomer SP-170 (manufactured by ADEKA), Sun-Aid SI-100L (manufactured by Sanshin Chemical Industry), Rhodorsil 2074 (manufactured by Rhodia Japan) and the like can be mentioned.

  In particular, when a monomer having a cyclic ether group is used as the monomer 22, the following cationic polymerization initiator (photoacid generator) is preferably used.

  For example, sulfonium salts such as triphenylsulfonium trifluoromethanesulfonate, tris (4-t-butylphenyl) sulfonium-trifluoromethanesulfonate, diazonium salts such as p-nitrophenyldiazonium hexafluorophosphate, ammonium salts, phosphonium salts, diphenyliodonium Trifluoromethanesulfonate, iodonium salts such as (triccumyl) iodonium-tetrakis (pentafluorophenyl) borate, quinonediazides, diazomethanes such as bis (phenylsulfonyl) diazomethane, 1-phenyl-1- (4-methylphenyl) sulfonyloxy- Sulfones such as 1-benzoylmethane and N-hydroxynaphthalimide-trifluoromethanesulfonate Esters, disulfones such as diphenyldisulfone, tris (2,4,6-trichloromethyl) -s-triazine, 2- (3.4-methylenedioxyphenyl) -4,6-bis- (trichloromethyl)- and compounds such as triazines such as s-triazine. These photoacid generators may be used alone or in combination.

  The content of the polymerization initiator is preferably 0.01 parts by mass or more and 5 parts by mass or less, and more preferably 0.02 parts by mass or more and 3 parts by mass or less with respect to 100 parts by mass of the polymer 21. Thereby, the monomer 22 can be reacted rapidly without deteriorating the optical characteristics and mechanical characteristics of the layer 3.

(Other additives)
In addition to these, various crosslinking agents may be added to the layer 3. For example, carbodilite V-02-L2 (manufactured by Nisshinbo Chemical Co., Ltd.) can be used as a crosslinking agent for aqueous (meth) acrylates for crosslinking of (meth) acrylic monomers.

  The layer 3 may contain a sensitizer. The sensitizer increases the sensitivity of the polymerization initiator to the actinic radiation R, reduces the time and energy required for the activation (reaction or decomposition) of the polymerization initiator, and a wavelength suitable for the activation of the polymerization initiator. Has a function of changing the wavelength of the active radiation R.

  Specifically, an anthracene such as 9,10-dibutoxyanthracene (CAS No. 76275-14-4) is selected depending on the sensitivity of the polymerization initiator and the peak wavelength of absorption of the sensitizer. , Xanthones, anthraquinones, phenanthrenes, chrysene, benzpyrenes, fluoranthenes, rubrenes, pyrenes, indanthrines, thioxanthen-9-ones, etc. These can be used alone or as a mixture.

  More specifically, for example, 2-isopropyl-9H-thioxanthen-9-one, 4-isopropyl-9H-thioxanthen-9-one, 1-chloro-4-propoxythioxanthone, phenothiazine or these A mixture is mentioned.

  The content of the sensitizer in the layer 3 is preferably 0.01% by mass or more, more preferably 0.5% by mass or more, and further preferably 1% by mass or more. In addition, it is preferable that an upper limit is 5 mass% or less.

  In addition, layer 3 includes a catalyst precursor, a promoter, an antioxidant, an ultraviolet absorber, a light stabilizer, a silane coupling agent, a coating surface improver, a thermal polymerization inhibitor, a leveling agent, and a surfactant. , Colorants, storage stabilizers, plasticizers, lubricants, fillers, inorganic particles, deterioration inhibitors, wettability improvers, antistatic agents, and the like.

  Such a layer 3 is formed by applying a composition (varnish) containing raw materials onto a substrate 30 as shown in FIG. 3A, for example, and then drying it after forming it into a layer shape.

  [2] Next, as shown in FIG. 3B, the layer 3 is irradiated with actinic radiation R through a mask 4 in which an opening (window) 41 is formed.

  The exposure method may be contact exposure using a mask, proximity exposure, direct drawing method, or the like.

  The mask 4 may be a separate one (for example, a plate shape or a film shape) or a film shape formed on the layer 3 by, for example, a vapor deposition method or a coating method.

  Examples of preferable mask 4 include a photomask made of quartz glass or a PET base material, a stencil mask, a metal thin film formed by a vapor deposition method (evaporation, sputtering, etc.), etc. Among these, it is particularly preferable to use a photomask or a stencil mask. This is because a fine pattern can be formed with high accuracy, and handling is easy, which is advantageous for improving productivity.

  Note that when the light having high directivity such as laser light is used as the active radiation R, the use of the mask 4 may be omitted.

  The actinic radiation R irradiated to the layer 3 may be any material that can reduce the volume of the polymer 21 and can react with the monomer 22. For example, in addition to visible light, ultraviolet light, infrared light, and laser light, an electron beam or X Lines or the like can also be used.

  Among these, it is preferable that the active radiation R has a peak wavelength in a wavelength range of 200 to 450 nm. Thereby, the reaction of the monomer 22 can be particularly facilitated, and the deterioration of the polymer 21 can be suppressed to a relatively low level.

The irradiation amount of actinic radiation R is preferably in the range of about 0.01~9J / cm ^2, more preferably about ^{0.1~6J / cm 2, 0.2~3J / cm} 2 of about More preferably.

  When the active radiation R is selectively applied to the irradiation region 31 of the layer 3, the volume of the polymer 21 decreases in the irradiation region 31. Thereby, the surface of the irradiation region 31 is recessed, and the surface of the non-irradiation region 32 is relatively protruded to form the convex portion 12. In addition, although the detailed mechanism in which the volume of the polymer 21 decreases is not clear, the shrinkage | contraction by the polymerization reaction in the polymer 21 further progressing, the shrinkage | contraction by partial structure in the polymer 21 etc. can be considered. In addition, the partial structure which leaves | separates from the polymer 21 includes the leaving group etc. which couple | bond with the main chain of each polymer mentioned above, for example.

  On the other hand, the monomer 22 is polymerized in the irradiation region 31. When the monomer 22 is polymerized, the amount of the monomer 22 in the irradiation region 31 decreases, so that the monomer 22 in the non-irradiation region 32 of the layer 3 is added to the irradiation region 31 as shown in FIG. Moving. As a result, in layer 3, the concentration of monomer 22 and its reactants in irradiated region 31 increases, while in non-irradiated region 32, the concentration of monomer 22 decreases.

  When such a concentration distribution of the monomer 22 is formed, the volume of the layer 3 changes accordingly. Specifically, in the irradiation region 31 to which the monomer 22 is moved, a bump is generated as the monomer 22 increases. Therefore, in the irradiation region 31, the depression due to the volume reduction of the polymer 21 and the bulge caused by the increase in the monomer 22 are combined to cause a change in the surface shape. In the present invention, the composition of the layer 3, physical properties, irradiation conditions of the actinic radiation R, and the like are appropriately set, so that the volume reduction of the polymer 21 is made superior and the irradiation region 31 is recessed. In one example, the polymer 21 containing a leaving group may be used, and the addition amount of the monomer 22 may be set within the above range. As a result, the surface of the non-irradiated region 32 of the layer 3 becomes relatively higher than the irradiated region 31, and the convex portion 12 shown in FIG. On the other hand, the irradiation region 31 has a relatively low surface height and becomes the flat portion 11 described above.

  In addition, since the refractive index of the monomer 22 and its reaction product is lower than that of the polymer 21, the refractive index of the irradiated region 31 is lower than that of the non-irradiated region 32 by forming such a concentration distribution. Become. As a result, the refractive index difference that the refractive index of the irradiated region 31 is low and the refractive index of the non-irradiated region 32 is high is formed in the layer 3, and the refractive index distribution N described above is formed. In addition, since the refractive index of the reaction product of the monomer 22 as described above is substantially the same as the refractive index of the monomer 22 before polymerization (the refractive index difference is about 0 to 0.001), the monomer 22 As the polymerization proceeds, the refractive index decreases according to the amount of the monomer 22 and the amount of the reactant of the monomer 22.

  The movement of the monomer 22 is considered to be triggered by the consumption of the monomer 22 in the irradiation region 31. For this reason, it is considered that the monomers 22 in the entire non-irradiated region 32 do not move toward the irradiated region 31 all at once, but gradually move from a portion close to the irradiated region 31 and successively move so as to compensate for this. Therefore, the concentration distribution of the monomer 22 inevitably has a gentle slope, and as a result, the surface shape of the convex portion 12 and the shape of the refractive index distribution N are each configured by a smooth curve. Specifically, as shown in FIG. 3D, the shape of the convex portion 12 is such that the surface height gradually decreases from the apex 121 having the highest surface height to the outer edge of the convex portion 12. And a gradually decreasing portion 122. The shape of the refractive index distribution N is such that the refractive index gradually decreases from the top 121 toward the outer edge of the convex portion 12 as shown in FIG. Therefore, since the microlens array 1 has a smooth shape change, for example, even when bent, the microlens array 1 has few sites that cause cracks and the like, and as a result, has excellent durability such as bending resistance. It will be a thing. Further, since the change in the refractive index distribution N is smooth, the effect of confining light in the convex portion 12 becomes particularly remarkable.

  Further, as described above, the refractive index distribution N has a low refractive index portion NL that is located near the boundary between the convex portion 12 and the flat portion 11 and has a refractive index that is locally smaller than the periphery. However, it is considered that the low refractive index portion NL is also formed by the movement of the monomer 22. Specifically, as a result of the gradual movement of the monomer 22, the concentration of the monomer 22 becomes the highest in the vicinity of the boundary between the convex portion 12 and the flat portion 11, and as a result, the low refractive index portion NL is formed. it is conceivable that.

  Further, in the present invention, the microlens array 1 having such excellent optical performance can be manufactured through a simple process of irradiating the active radiation R to a region other than the region to be the convex portion 12 of the layer 3. . For this reason, even in the microlens array 1 in which the convex portions 12 are arranged in a complicated pattern, it can be manufactured only by appropriately setting the irradiation region 31, regardless of the complexity of the pattern. The manufacturing process is very simple. Therefore, the microlens array 1 with high optical performance can be manufactured at a low manufacturing cost.

  Conventionally, when manufacturing a microlens array, precision processing techniques such as a photolithography method and an etching method have been used, but these all require large and expensive devices and a large amount of secondary materials. there were. For this reason, there is a possibility that the constituent materials of the microlens array are deteriorated or contaminated by the contact of the auxiliary materials such as the photoresist and the etching solution.

  On the other hand, in the present invention, since such a large apparatus and a large amount of secondary materials are unnecessary, it is easy to reduce the manufacturing cost, and it is possible to prevent deterioration and contamination of the constituent materials.

  When the polymer 21 has a leaving group, the leaving group is released in the irradiation region 31 with the irradiation of the active radiation R. Thereby, the surface shape of the irradiation region 31 and the refractive index of the polymer 21 change. For this reason, the surface shape and refractive index of the irradiation region 31 can be controlled more finely together with the surface shape change and refractive index change caused by the movement of the monomer 22 described above.

  In many cases, the wavelength at which the monomer 22 reacts (or the wavelength at which the polymerization initiator reacts) is different from the wavelength at which the leaving group leaves. Therefore, for example, by irradiating the actinic radiation R having a wavelength at which the monomer 22 reacts first, and then irradiating the wavelength at which the leaving group is released by changing the irradiation region, the surface shape and refractive index of the irradiation region 31 are further increased. It can be finely controlled.

  Similarly, even when a plurality of monomers 22 having different reacting wavelengths are used or a plurality of polymerization initiators having different reacting wavelengths are used, the active radiation R is irradiated a plurality of times while changing the wavelength and the irradiation region. The surface shape and refractive index of the irradiation region 31 can be controlled more finely. As a result, it is possible to obtain a microlens array 1 with a small amount of various aberrations and a very high optical performance.

  In the irradiation region 31, the active radiation R may be irradiated with a uniform integrated dose, or may be irradiated so as to have an integrated dose distribution with a predetermined bias.

  When the active radiation R is applied to the irradiation region 31 so that the integrated dose distribution is uniform, in addition to the advantage that the irradiation process is simple, the movement of the monomer 22 can be easily controlled, There is an advantage that the surface shape and the refractive index distribution can be easily controlled to a desired shape. In this case, a smooth curved surface such as a rotating curved surface of a normal distribution curve can be easily obtained with a natural concentration gradient of the monomer 22. The uniform integrated dose means that the difference between the maximum and minimum of the integrated dose in the irradiation region 31 is 10% or less of the average value.

  On the other hand, when the actinic radiation R is irradiated so as to have an integrated dose distribution with a predetermined bias with respect to the irradiation region 31, the degree of difficulty in controlling the movement of the monomer 22 increases, but the volume reduction amount of the polymer 21 and The moving amount and moving speed of the monomer 22 can be finely controlled. For example, even an asymmetric curved surface can be formed.

  By controlling the integrated irradiation amount distribution in this manner, the volume reduction amount of the polymer 21 and the movement amount of the monomer 22 can be changed, and the surface shape of the convex portion 12 and the refractive index distribution N can be controlled more finely.

  In addition, when moving the monomer in the layer 3, the volume reduction amount of the polymer 21, the moving amount and moving speed of the monomer 22 can be controlled by appropriately changing the drying conditions of the layer 3. For example, the movement amount of the monomer 22 can be suppressed by increasing the degree of drying.

  The Shore D hardness of the polymer 21 is preferably about 35 to 95, more preferably about 40 to 90, and even more preferably about 45 to 85. The polymer 21 having such a hardness allows the monomer 22 to move reliably while imparting necessary and sufficient mechanical properties to the microlens array 1. For this reason, the convex part 12 which has sufficient protrusion height and sufficient refractive index difference can be formed by using the polymer 21 of this hardness.

  For the same reason, the Rockwell hardness of the polymer 21 is preferably about 40 to 125 on the M scale, more preferably about 50 to 115, and still more preferably about 60 to 110.

  Moreover, it is preferable that the softening point of the polymer 21 is 90 degreeC or more, and it is more preferable that it is 95-280 degreeC. Thereby, the microlens array 1 has necessary and sufficient mechanical characteristics, and has a sufficient protrusion height and a sufficient refractive index difference. In addition, the softening point of the polymer 21 is the glass transition temperature or melting point of the polymer 21, and when both are present, it indicates the lower one.

  Such physical properties of the polymer 21 are important for reliably forming the convex portion 12. That is, when the hardness of the polymer 21 is too low or the softening point is too low, depending on the dimensions and constituent materials of the microlens array 1, the mechanical characteristics of the microlens array 1 are insufficient and it is difficult to maintain the shape. Or it may be difficult to handle. On the other hand, when the hardness of the polymer 21 is too high or the softening point is too high, the movement of the monomer 22 becomes insufficient and the refractive index distribution N may not be formed. Further, even if the layer 3 is irradiated with the actinic radiation R, there is a possibility that a sufficient volume reduction does not occur.

  Moreover, you may make it perform irradiation of the active radiation R in inert gas atmosphere like nitrogen atmosphere and argon atmosphere as needed. Thereby, the oxidation and modification | denaturation of the polymer 21 and the monomer 22 can be suppressed, and the microlens array 1 more excellent in the optical characteristic can be obtained.

  Thereafter, the layer 3 is heat-treated as necessary. In this heat treatment, further movement of the monomer 22 is suppressed.

  The heating temperature in this heat treatment is not particularly limited, but is preferably about 30 to 180 ° C, and more preferably about 40 to 160 ° C.

  Moreover, although heating time is suitably set according to heating temperature, it is preferable that it is about 0.05 to 2 hours, and it is more preferable that it is about 0.1 to 1 hour.

  As described above, the convex portion 12 is formed on the layer 3, and the microlens array 1 can be obtained.

  Note that the refractive index distribution N formed in the microlens array 1 is, for example, (1) a refractive index dependent interference fringe is observed using an interference microscope (dual-beam interference microscope), and the refractive index distribution is determined from the interference fringe. N can be specified by a method for specifying N, (2) a refraction near field method (RNF), or the like. Among these, the refractive near field method can employ the measurement conditions described in, for example, JP-A-5-332880. On the other hand, the interference microscope is useful in that the refractive index distribution N can be easily specified.

  Further, since the refractive index distribution N formed in the microlens array 1 has a certain correlation with the concentration of the monomer 22 and its reaction product, the concentration distribution of the monomer 22 and its reaction product is acquired. The shape can also be indirectly specified. For example, FT-IR or TOF-SIMS line analysis, surface analysis, or the like can be used to measure the concentration of the monomer 22 or its reactant.

  In addition, the layer 3 to which the actinic radiation R is irradiated may be a laminate of a plurality of layers 3 as described above. Thereby, the height of the convex part 12 can be raised substantially.

<< Second Embodiment >>
Next, a microlens array to which the second embodiment of the optical component of the present invention (the concavo-convex structure of the present invention) is applied will be described.

  FIG. 4 is a cross-sectional view for explaining a microlens array to which the second embodiment of the optical component of the present invention is applied and a manufacturing method thereof. In the following description, the upper surface in FIG. 4 is referred to as “front surface”, and the lower surface is referred to as “back surface”.

  Hereinafter, although 2nd Embodiment is described, in the following description, difference with 1st Embodiment is demonstrated and the description is abbreviate | omitted about the same matter.

  In the second embodiment, when the microlens array 1 is manufactured, a highly flexible substrate 30 is used as the substrate 30 for forming the layer 3. Specifically, various resin films or the like are used as the substrate 30. By using such a highly flexible substrate 30, when the irradiation region 31 of the layer 3 is recessed, not only the surface side of the layer 3 is recessed downward as shown in FIG. While pulling up the highly flexible substrate 30, the back side of the layer 3 is also recessed upward. As a result, the resulting microlens array 1 has convex portions 12 with a higher protrusion height, both of which are partially recessed on both the front surface and the back surface, and both the front surface and the back surface are partially protruded. It will have.

  Such a convex part 12 behaves like a so-called biconvex lens. That is, the convex portion 12 according to the first embodiment behaves like a plano-convex lens, whereas the convex portion 12 according to the present embodiment can behave like a biconvex lens having a more excellent light collecting effect. . As a result, the microlens array 1 with more excellent optical performance can be obtained.

  In the first embodiment, a substrate having a relatively high rigidity may be used as the substrate 30. The rigidity of the substrate 30 may be appropriately set according to the depression force of the layer 3. For example, in the case of the resin substrate 30, the thickness may be 0.5 mm or more as an example.

  On the other hand, in this embodiment, it is sufficient to use a substrate 30 having a flexibility that does not hinder the indentation force of the layer 3. For example, in the case of a resin substrate 30, the thickness is set to less than 0.5 mm as an example. do it.

  In addition, by forming a desired uneven shape on the upper surface of the substrate 30 in advance, the uneven shape is transferred to the layer 3 formed on the substrate 30, and as a result, the uneven shape is formed on the back surface 13 of the microlens array 1. Can be transferred. Thereby, the back surface shape of the convex part 12 can be determined by the uneven | corrugated shape formed on the board | substrate 30, and the surface shape of the convex part 12 can be determined by the depression of the layer 3. FIG. As a result, convex portions 12 having different shapes on the front and back sides are obtained.

<Optical device>
By mounting the optical component of the present invention as described above on an optical device, for example, a highly reliable optical device having excellent optical performance can be obtained.

  Examples of the optical device including the optical component of the present invention include various imaging devices such as a CCD image sensor and a CMOS (Complementary Metal Oxide Semiconductor) image sensor, various display devices such as a liquid crystal display device, an organic EL device, and a liquid crystal projector. And various optical communication devices such as an optical fiber connection ferrule and an optical waveguide connection ferrule, and various optical analysis devices such as a spectroscopic analysis device.

  FIG. 5 is a cross-sectional view showing a structure around a pixel of a CCD image sensor to which an embodiment of the optical device of the present invention is applied. In the following description, for convenience of explanation, the upper part in FIG. 5 is referred to as “upper” and the lower part is referred to as “lower”.

  A CCD image sensor 5 shown in FIG. 5 includes a semiconductor substrate 51 on which a light receiving unit such as a photodiode 511 is formed, and a circuit (not shown) such as a reading unit that is stacked on the semiconductor substrate 51 and reads an electric signal accompanying light reception. ), A color filter 53 stacked on the circuit unit 52, and a microlens array 1 stacked on the color filter 53. In such a CCD image sensor 5, generation of stray light that leaks between pixels in the microlens array 1 can be suppressed, so that generation of noise such as smear can be suppressed.

  The concavo-convex structure, the method for manufacturing the concavo-convex structure, the optical component, and the optical device of the present invention have been described above, but the present invention is not limited to this.

  For example, the shape of the convex surface is not limited to the above, and may be a so-called higher-order curved surface such as a quadratic curved surface, a quartic curved surface, or a hexagonal curved surface, a hyperboloid, an elliptical surface, or the like.

Next, examples of the present invention will be described.
1. Production of microlens array (Example 1)
(1) Synthesis of polyolefin resin 7.2 g (40.1 mmol) of hexylnorbornene (HxNB), diphenylmethylnorbornenemethoxy in a glove box whose moisture and oxygen concentrations are both controlled to 1 ppm or less and filled with dry nitrogen 12.9 g (40.1 mmol) of silane was weighed into a 500 mL vial, 60 g of dehydrated toluene and 11 g of ethyl acetate were added, and the top was sealed with a silicon sealer.

  Next, 1.56 g (3.2 mmol) of Ni catalyst and 10 mL of dehydrated toluene were weighed in a 100 mL vial, and a stirrer chip was placed and sealed, and the catalyst was thoroughly stirred to dissolve completely.

  When 1 mL of this Ni catalyst solution was accurately weighed with a syringe, and quantitatively injected into the vial bottle in which the two kinds of norbornene were dissolved and stirred at room temperature for 1 hour, a marked increase in viscosity was confirmed. At this point, the stopper was removed, 60 g of tetrahydrofuran (THF) was added, and the mixture was stirred to obtain a reaction solution.

  In a 100 mL beaker, 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (concentration 30%) and 30 g of ion-exchanged water were added and stirred to prepare an aqueous solution of peracetic acid on the spot. Next, the total amount of this aqueous solution was added to the above reaction solution and stirred for 12 hours to reduce Ni.

  Next, the treated reaction solution was transferred to a separatory funnel, the lower aqueous layer was removed, and then 100 mL of a 30% aqueous solution of isopropyl alcohol was added and vigorously stirred. The aqueous layer was removed after standing and completely separating the two layers. After repeating this water washing process three times in total, the oil layer was dropped into a large excess of acetone to reprecipitate the polymer produced, separated from the filtrate by filtration, and then in a vacuum dryer set at 60 ° C. Polymer # 1 was obtained by heating and drying for 12 hours. The molecular weight distribution of the polymer # 1 was Mw = 100,000 and Mn = 40,000 by GPC measurement. The molar ratio of each structural unit in polymer # 1 was 50 mol% for the hexylnorbornene structural unit and 50 mol% for the diphenylmethylnorbornenemethoxysilane structural unit, as determined by NMR. Polymer # 1 had a softening point of 230 ° C. and a Shore D hardness of 43.

(2) Production of polyolefin lens-forming composition 10 g of the purified polymer # 1 was weighed into a 100 mL glass container, and 40 g of mesitylene, 0.01 g of antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyl oxetane monomer ( Toa Gosei CHOX, CAS # 483303-3-25-9, molecular weight 186, boiling point 125 ° C./1.33 kPa) 2 g, polymerization initiator (photoacid generator) Rhodosil Photoinitiator 2074 (Rhodia, CAS # 178233-72-2) (0.0125 g in 0.1 mL of ethyl acetate) was added and dissolved uniformly, and then filtered through a 0.2 μm PTFE filter to obtain a clean lens-forming composition. Polymer # 1 has a function of releasing a leaving group upon irradiation with actinic radiation, and a so-called photobleaching phenomenon occurs.

(3) Production of lens The composition for forming a lens was uniformly applied on a polyethersulfone substrate with a doctor blade, and then placed in a dryer at 50 ° C. for 10 minutes. After removing the solvent to form a coating film, a photomask in which openings having a perfect circle shape with a diameter of 50 μm were arranged at intervals of 50 μm was pressure-bonded onto the obtained coating film. And the ultraviolet-ray was irradiated with the parallel exposure machine through the photomask with respect to the film. The cumulative amount of ultraviolet light was 200 mJ / cm ² .

  Next, the photomask was removed and placed in an oven at 150 ° C. for 30 minutes. Thereby, a microlens array was obtained. When this was taken out of the oven and measured in the vicinity of the non-exposed portion using a laser microscope, a convex lens shape having a height of 5 μm and a curvature radius of 60 μm was measured.

2. Evaluation of Microlens Array With respect to the microlens array obtained in the example, a refractive index distribution from a convex portion to a flat portion was obtained by an interference microscope. As a result, it was recognized that the refractive index distribution of the convex portion was a distribution in which the refractive index gradually increased from the outer edge side to the central side of the convex portion. Further, it was recognized that there was a minimum value of the annular refractive index (low refractive index portion NL) distributed so as to surround the convex portion in the vicinity of the boundary between the convex portion and the flat portion.

  In the obtained refractive index distribution, the refractive index difference d1 between the maximum value of the refractive index at the convex portion and the maximum value of the refractive index at the flat portion was 0.010.

  The refractive index difference d2 between the minimum value of the low refractive index portion NL and the maximum value of the refractive index in the flat portion was 23% of the refractive index difference d1.

  In addition, a microlens array was produced using an acrylic resin and an epoxy resin instead of the polyolefin resin, but as with the polyolefin resin, a convex lens shape was formed in the non-exposed part, The refractive index distribution was such that the refractive index gradually increased from the outer edge side to the center side of the convex portion.

DESCRIPTION OF SYMBOLS 1 Microlens array 11 Flat part 12 Convex part 121 Top part 122 Decrease part 13 Back surface 21 Polymer 22 Monomer 3 layer 30 Substrate 31 Irradiation area 32 Non-irradiation area 4 Mask 41 Opening 5 CCD image sensor 51 Semiconductor substrate 511 Photodiode 52 Circuit part 53 Color filter N Refractive index distribution NL Low refractive index part R Actinic radiation

Claims (10)

A concavo-convex structure having a convex portion whose surface partially protrudes,
The projection is partially irradiated with actinic radiation to a layer containing a polymer and a monomer having a refractive index lower than that of the polymer, so that the volume occupied by the polymer is reduced and the irradiation region is recessed. A non-irradiated area is a part that protrudes relatively with it,
The convex-concave structure is characterized in that the refractive index distribution of the convex portion includes a distribution in which the refractive index gradually increases from the outer edge side to the central side of the convex portion.   The concavo-convex structure according to claim 1, comprising a monomer concentration distribution in which the concentration of the monomer gradually decreases from the outer edge side to the center side of the convex portion.   The concavo-convex structure according to claim 1, wherein the convex portion has a portion having the highest projecting height on the surface and a portion in which the projecting height gradually decreases from there to the periphery. .   The concavo-convex structure according to claim 3, wherein the refractive index distribution of the convex portion is a distribution in which the refractive index is highest in a portion where the protrusion height is highest.   The concavo-convex structure body according to any one of claims 1 to 4, wherein the refractive index distribution of the concavo-convex structure body includes a minimum value of a refractive index located adjacent to the outside of the convex portion.   The concavo-convex structure according to any one of claims 1 to 5, wherein the convex portion is formed by partially projecting a front surface and a back surface facing the front surface. Irradiating actinic radiation partially to a layer comprising a polymer and a monomer having a refractive index lower than that of the polymer,
A convex part formed by relatively projecting the surface of the non-irradiated region by utilizing the fact that the volume of the polymer decreases in the irradiated region irradiated with the active radiation and the surface of the irradiated region is partially recessed. A process for producing a concavo-convex structure, characterized in that   The method for manufacturing a concavo-convex structure according to claim 7, wherein the active radiation is irradiated so that the integrated light amount distribution is uniform with respect to the irradiation region.   An optical component comprising the uneven structure according to any one of claims 1 to 6.   An optical device comprising the optical component according to claim 9.

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