Method for producing structure, stereolithograpy method, stereolithograpy device, optical diffraction element, and optical computation device

Abstract

In the present invention, a region corresponding to the inside of a structure to be formed is irradiated with: polymerization promoting light (L1) for promoting the polymerization of a monomer (M) stored in a container (11) together with a dye; and binding promoting light (L3) for promoting the binding of the pigment to the monomer (M). The number of times of each point is irradiated with the polymerization promoting light (L1) is set according to the two-dimensional thickness distribution of the structure to be formed, and the energy of the binding promoting light (L3) applied to each point is set according to the two-dimensional refractive index distribution of the structure to be formed.

Description

Structure manufacturing method, optical shaping method, optical shaping device, optical diffraction element, and optical computing device

[0001] The present invention relates to a photolithography method and a photolithography device, and a method for manufacturing a structure using the same.The present invention also relates to an optical diffraction element and an optical computing device including the same.

[0002] An optical diffraction element has a plurality of cells, and optically performs a predetermined calculation by causing signal light transmitted through each cell to interfere with each other. Patent Document 1 discloses an optical diffraction element in which the thickness is set for each cell, and an optical diffraction element in which the refractive index is set for each cell.

[0003] U.S. Patent Publication No. 11,392,830

[0004] If the amount of phase modulation for each cell can be freely set, the content of the optical calculation to be performed by the optical diffraction element can be freely determined. However, the method of setting the thickness of the optical diffraction element for each cell and the method of setting the refractive index of the optical diffraction element for each cell each have a limit to the range of the phase modulation amount that can be set for each cell. Therefore, the content of the optical calculation that can be performed by the optical diffraction element is limited.

[0005] If both the thickness and refractive index of an optical diffraction element could be set independently for each cell, the range of phase modulation amounts that can be set for each cell would be expanded. However, no optical diffraction element is known that allows both the thickness and refractive index to be set independently for each cell. Furthermore, to manufacture such an optical diffraction element, a manufacturing method for a structure that allows both a two-dimensional thickness distribution and a two-dimensional refractive index distribution to be set independently is required, but such a manufacturing method is also unknown.

[0006] One aspect of the present invention has been made in view of the above-mentioned problems, and its purpose is to provide a technique that allows both a two-dimensional thickness distribution and a two-dimensional refractive index distribution to be set independently.

[0007] A method for manufacturing a structure according to one aspect of the present invention includes: a first irradiation step of irradiating a region of a modeling surface set between a bottom plate of the container and a modeling table, the region corresponding to the interior of the structure to be modeled, with polymerization-promoting light that promotes polymerization of a monomer stored in the container together with a dye; and a second irradiation step of irradiating the region with bonding-promoting light that promotes bonding of the dye to the monomer or the polymer obtained by the polymerization, while lifting the modeling table; an exposure step of repeating these steps; a swelling step of swelling the gel modeled by the exposure step; and a step of extracting from the hydrogel obtained by the swelling step the hydrogel that bonds to the polymer. The method includes a washing step of removing unbound dye, which is dye that has not bound to the polymer, by washing; a deposition step of forming, by deposition, refractive index adjusting particles whose nuclei are dyes bound to the polymer within the hydrogel obtained by the washing step; and a drying and shrinking step of drying and shrinking the hydrogel obtained by the deposition step. In the first irradiation step, the number of times that each point is irradiated with polymerization promotion light is set according to the two-dimensional thickness distribution of the structure to be formed, and in the second irradiation step, the energy of the bond promotion light irradiated to each point is set according to the two-dimensional refractive index distribution of the structure to be formed.

[0008] A photopolymerization method according to one aspect of the present invention includes a first irradiation step of irradiating a region of a molding surface set between a bottom plate of the container and a molding table, the region corresponding to the interior of a structure to be molded, with polymerization-promoting light that promotes polymerization of a monomer stored in a container together with a dye, and a second irradiation step of irradiating the region with bond-promoting light that promotes bonding of the dye to the monomer or the polymer obtained by the polymerization, wherein the first irradiation step and the second irradiation step are repeated while the molding table is raised, and the number of times that the polymerization-promoting light is irradiated to each point in the first irradiation step is set according to the two-dimensional thickness distribution of the structure to be molded, and the energy of the bond-promoting light irradiated to each point in the second irradiation step is set according to the two-dimensional refractive index distribution of the structure to be molded.

[0009] A photopolymerization device according to one aspect of the present invention comprises a first irradiation unit that irradiates a region of a molding surface set between a bottom plate of the container and a molding table, the region corresponding to the interior of a structure to be molded, with polymerization promotion light that promotes polymerization of a monomer stored in a container together with a dye, and a second irradiation unit that irradiates the region with bond promotion light that promotes bonding of the dye to the monomer or the polymer obtained by the polymerization. The irradiation of the polymerization promotion light by the first irradiation unit and the irradiation of the bond promotion light by the second irradiation unit are repeated while the molding table is lifted, and the number of times that the first irradiation unit irradiates each point with the polymerization promotion light is set according to the two-dimensional thickness distribution of the structure to be molded, and the energy of the bond promotion light irradiated to each point in the second irradiation process is set according to the two-dimensional refractive index distribution of the structure to be molded.

[0010] An optical diffraction element according to one aspect of the present invention has a plurality of cells whose thicknesses are set independently of each other, and optically performs a predetermined calculation by causing signal light transmitted through each cell to interfere with each other. The optical diffraction element includes refractive index adjusting particles having a dye as a nucleus, and the two-dimensional refractive index distribution in a direction intersecting the direction of incidence of the signal light is determined according to the two-dimensional concentration distribution of the refractive index adjusting particles in that direction.

[0011] According to one aspect of the present invention, it is possible to provide a technique that allows both a two-dimensional thickness distribution and a two-dimensional refractive index distribution to be set independently.

[0012] Fig. 4 is a cross-sectional view of a photo-fabrication apparatus according to one embodiment of the present invention. Fig. 5 is a flow diagram showing the flow of a photo-fabrication method (a method for manufacturing a structure) using the photo-fabrication apparatus shown in Fig. 1. Fig. 6 is a schematic diagram of a structure obtained by the exposure process, swelling process, cleaning process, deposition process, and dry shrinkage fixation shown in Fig. 2. Fig. 7 is a perspective view showing a specific example of an optical diffraction element formed by the photo-fabrication apparatus shown in Fig. 1. Fig. 8 is a partial cross-sectional view showing variations in the refractive index distribution of the optical diffraction element shown in Fig. 4.

[0013] (Configuration of Optical Prototyping Apparatus) The configuration of an optical prototyping apparatus 1 according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view of the optical prototyping apparatus 1.

[0014] 1, the optical shaping apparatus 1 is an apparatus for manufacturing a resin structure, and includes a container 11, a shaping table 12, a first irradiation unit 13, and a second irradiation unit 14. The optical shaping apparatus 1 also includes a lifting mechanism (not shown) that lifts the shaping table 12. Specific examples of the first irradiation unit 13 and the second irradiation unit 14 will be described later with reference to different drawings.

[0015] The container 11 is configured to store a liquid monomer M containing a dye or a solution of the monomer M containing a dye (hereinafter also simply referred to as "monomer M"). The container 11 is, for example, shaped like a box or a tub. The bottom plate of the container 11 is made of a light-transmitting material that transmits polymerization-promoting light L1, polymerization-inhibiting light L2, and bond-promoting light L3, which will be described later. The modeling table 12 is configured to support a gel G made of a polymer P obtained by polymerizing the monomer M. The modeling table 12 is, for example, shaped like a rectangular prism or a cylinder. The modeling table 12 is immersed in the monomer M so that its bottom surface faces the bottom plate of the container 11 in parallel.

[0016] The monomer M may be any monomer as long as it has the property of promoting polymerization (gelation) by the polymerization-promoting light L1 (described later) and the property of promoting bonding with the dye by the bonding-promoting light L3 (described later). In this embodiment, acrylic acid is used as the monomer M, but the monomer M is not limited to this.

[0017] The first irradiation unit 13 is configured to irradiate the printing surface PP, which is set between the bottom plate of the container 11 and the printing table 12, with polymerization promotion light L1. The polymerization promotion light L1 is light that promotes the polymerization (gelation) of the monomer M. For example, light with a wavelength that activates a polymerization initiator blended with the monomer M is used. In this embodiment, camphorquinone is used as the polymerization initiator, so light with a wavelength of 460 nm is used as the polymerization promotion light L1. The polymerization promotion light L1 travels in a direction intersecting the printing surface PP (in this embodiment, a direction perpendicular to the direction of the polymerization promotion light L1) and is focused so that its intensity is maximized on the printing surface PP. The polymerization promotion light L1 is irradiated, particularly, to a region of the printing surface PP that corresponds to the interior of the structure to be printed, and is used to promote the polymerization (gelation) of the monomer M present in that region.

[0018] The first irradiator 13 may also irradiate polymerization-inhibiting light L2 along with the polymerization-promoting light L1. The polymerization-inhibiting light L2 is light that inhibits the polymerization (gelation) of the monomer M. For example, light with a wavelength that activates a polymerization inhibitor compounded with the monomer M is used. In this embodiment, tetraethylthiuram disulfide is used as the photopolymerization inhibitor, and therefore light with a wavelength of 365 nm is used as the polymerization-inhibiting light L2. The polymerization-inhibiting light L2 also travels in the same direction as the polymerization-promoting light L1, i.e., in a direction intersecting the printing surface PP (in this embodiment, perpendicular to the direction of the polymerization-promoting light L1). The polymerization-inhibiting light L2 is irradiated, particularly, to an area of ​​the printing surface PP that corresponds to the exterior of the structure to be printed, and is used to inhibit the polymerization (gelation) of the monomer M present in that area. By employing a configuration in which the first irradiator 13 irradiates polymerization-inhibiting light L2, it becomes possible to perform stereolithography with a resolution higher than that determined by the spot size of the polymerization-promoting light L1 on the printing surface PP.

[0019] 1 illustrates a configuration in which polymerization-promoting light L1 is irradiated onto the printing surface PP after being (1) irradiated from the first irradiation unit 13, (2) transmitted through the beam splitter BS, and (3) reflected by the mirror M. The traveling direction of the polymerization-promoting light L1 described above is the traveling direction of the polymerization-promoting light L1 when it is incident on the printing surface PP, i.e., the traveling direction of the polymerization-promoting light L1 after being reflected by the mirror M. The same can be said for the polymerization-inhibiting light L2.

[0020] The first irradiator 13 may be configured as either (1) or (2) below. (1) The polymerization-promoting light L1 is irradiated onto the entire region of the printing surface PP that corresponds to the interior of the structure to be printed. (2) The polymerization-promoting light L1 is irradiated onto a portion of the region of the printing surface PP that corresponds to the interior of the structure to be printed. When the configuration (1) is adopted, the printing of each point constituting each layer of the structure is carried out all at once. On the other hand, when the latter configuration is adopted, the irradiation point of the polymerization-promoting light L1 is moved so as to scan the region of the printing surface PP that corresponds to the interior of each layer of the structure. As a result, the printing of each point constituting each layer of the structure is carried out sequentially. The same can be said for the polymerization-inhibiting light L2.

[0021] The second irradiation unit 14 is configured to irradiate the printing surface PP with bond promotion light L3. The bond promotion light L3 is light that promotes the bonding of a dye to the monomer M before polymerization (gelation) or the polymer P after polymerization (gelation). In this embodiment, light with a wavelength of 950 nm is used as the bond promotion light L3 to bond the cyanine fluorescent dye Cy3 using two-photon excitation. The bond promotion light L3 travels in the same direction as the polymerization promotion light L1 and the polymerization inhibition light L2, i.e., in a direction intersecting the printing surface PP (in this embodiment, perpendicular to the direction of the polymerization promotion light L1 and the polymerization inhibition light L2). The bond promotion light L3 is irradiated, particularly, to a region of the printing surface PP that corresponds to the interior of the structure to be printed, and is used to promote the bonding of the dye to the monomer M or polymer P present in that region.

[0022] The dye bonded to the monomer M or polymer P is used as a nucleus for forming particles having a refractive index increasing or decreasing effect (hereinafter also referred to as "refractive index adjusting particles"). Examples of refractive index adjusting particles having a refractive index increasing effect include particles obtained by depositing nanodiamond, titanium oxide, chalcogenite, or the like on a dye. Examples of refractive index adjusting particles having a refractive index decreasing effect include particles obtained by depositing hollow particles such as calcium fluoride or silica on a dye. The dye may be any dye that has the property of promoting bonding with the monomer M or polymer P by the bonding promotion light L3. In this embodiment, the cyanine fluorescent dye Cy3 is used as the dye, but the dye is not limited thereto.

[0023] The energy of the bond-promoting light L3 irradiated by the second irradiating unit 14 onto each point on the printing surface PP is set in accordance with the two-dimensional refractive index distribution of the structure to be printed.

[0024] For example, when forming particles having a refractive index increasing effect as refractive index adjusting particles, the following (1) and (2) are performed. (1) At points in the structure to be modeled where the refractive index should be increased, the irradiation intensity of the bond promotion light L3 is increased and / or the irradiation time of the bond promotion light L3 is extended so that the energy of the bond promotion light L3 is increased. Conversely, (2) At points in the structure to be modeled where the refractive index should be decreased, the irradiation intensity of the bond promotion light L3 is decreased and / or the irradiation time of the bond promotion light L3 is shortened so that the energy of the bond promotion light L3 is decreased. As a result, at points in the structure to be modeled where the refractive index should be increased, the proportion of the dye bonded to the monomer M or polymer P is increased, resulting in a higher concentration of the refractive index adjusting particles. Conversely, at points in the structure to be modeled where the refractive index should be decreased, the proportion of the dye bonded to the monomer M or polymer P is decreased, resulting in a lower concentration of the refractive index adjusting particles.

[0025] Alternatively, when forming particles having a refractive index lowering effect as refractive index-adjusting particles, the following (1) and (2) are performed. (1) At points in the structure to be modeled where the refractive index should be increased, the irradiation intensity of the bond promotion light L3 is reduced and / or the irradiation time of the bond promotion light L3 is shortened so that the energy of the bond promotion light L3 is reduced. Conversely, (2) At points in the structure to be modeled where the refractive index should be reduced, the irradiation intensity of the bond promotion light L3 is increased and / or the irradiation time of the bond promotion light L3 is lengthened so that the energy of the bond promotion light L3 is increased. As a result, at points in the structure to be modeled where the refractive index should be increased, the proportion of the dye bonded to the monomer M or polymer P is reduced, resulting in a lower concentration of the refractive index-adjusting particles. Conversely, at points in the structure to be modeled where the refractive index should be reduced, the proportion of the dye bonded to the monomer M or polymer P is increased, resulting in a higher concentration of the refractive index-adjusting particles.

[0026] 1 illustrates a configuration in which the bond promotion light L3 is irradiated onto the build surface PP after being (1) irradiated from the second irradiating unit 14, (2) reflected by the beam splitter BS, and (3) reflected by the mirror M. The traveling direction of the bond promotion light L3 described above is the traveling direction of the bond promotion light L3 when it is incident on the build surface PP, i.e., the traveling direction of the bond promotion light L3 after being reflected by the mirror M.

[0027] (Flow of the stereolithography method) The flow of the stereolithography method S1 using the stereolithography apparatus 1 will be described with reference to Figs. 2 and 3. Fig. 2 is a flow diagram showing the flow of the stereolithography method S1. Fig. 3 is a schematic diagram showing structures obtained by each of the exposure step S12, swelling step S13, cleaning step S14, deposition step S15, and drying and shrinkage step S16, which will be described later. Fig. 3 illustrates the process of forming seven pillars P1 to P7 on the lower surface of a substrate B that has been previously formed.

[0028] The stereolithography method S1 includes a pretreatment step S11, an exposure step S12, a swelling step S13, a cleaning step S14, a deposition step S15, and a drying step S16. The stereolithography method S1 can also be referred to as a method for manufacturing a structure.

[0029] The pre-treatment step S11 is a step of storing the monomer M in the container 11 and immersing the modeling table 12 in the monomer M. Here, the modeling table 12 is immersed in the monomer M so that its bottom surface faces and is parallel to the bottom plate of the container 11. The storing of the monomer M and the immersion of the modeling table 12 may be performed manually by an operator or automatically by the optical modeling apparatus 1 or another device.

[0030] The exposure process S12 includes a first irradiation process S12a, a second irradiation process S12b, and a pulling-up process S12c. The first irradiation process S12a, the second irradiation process S12b, and the pulling-up process S12c are repeated a predetermined number of times. For example, when a structure is divided into n layers (n is any natural number) and each layer is molded, a cycle including the first irradiation process S12a, the second irradiation process S12b, and the pulling-up process S12c is repeated n times. Here, a cycle refers to a unit of repetition when the first irradiation process S12a, the second irradiation process S12b, and the pulling-up process S12c are repeated, and the first irradiation process S12a, the second irradiation process S12b, and the pulling-up process S12c are performed once per cycle.

[0031] The first irradiation step S12a is a step in which the first irradiation unit 13 irradiates the printing surface PP with polymerization-promoting light L1. As described above, the polymerization-promoting light L1 is irradiated onto the printing surface PP in a region that corresponds to the interior of the structure to be printed. This promotes polymerization (gelation) of the monomer M in the region of the printing surface PP that corresponds to the interior of the structure to be printed. The first irradiation unit 13 in the first irradiation step S12a may be controlled manually by an operator or automatically by the optical printing apparatus 1 or another device.

[0032] In the first irradiation step S12a, the number of times that each point on the printing surface PP is irradiated with the polymerization-promoting light L1 is set according to the two-dimensional thickness distribution of the structure to be printed. For example, assuming m1<m2<n, a thin point having a thickness equivalent to m1 layers is irradiated with the polymerization-promoting light L1 from the first cycle to the m1 cycle (number of times that the polymerization-promoting light L1 is irradiated = m1 times), and a thick point having a thickness equivalent to m2 layers is irradiated with the polymerization-promoting light L1 from the first cycle to the m2 cycle (number of times that the polymerization-promoting light L1 is irradiated = m2 times).

[0033] In the first irradiation step S12a, the first irradiator 13 may irradiate polymerization-inhibiting light L2 in addition to the polymerization-promoting light L1. As described above, the polymerization-inhibiting light L2 is irradiated onto an area of ​​the printing surface PP that corresponds to the outside of the structure to be printed. This inhibits polymerization (gelation) of the monomer M in the area that corresponds to the outside of the structure to be printed. In this case, it becomes possible to perform photolithography with a higher resolution than the resolution determined by the spot size of the polymerization-promoting light L1 on the printing surface PP.

[0034] The second irradiation step S12b is a step in which the second irradiation unit 14 irradiates the printing surface PP with bond-promoting light L3. As described above, the bond-promoting light L3 is irradiated onto the printing surface PP in an area corresponding to the interior of the structure to be printed. This promotes the bonding of the dye to the polymer P in the area of ​​the printing surface PP corresponding to the interior of the structure to be printed. The second irradiation unit 14 in the second irradiation step S12b may be controlled manually by an operator or automatically by the optical printing apparatus 1 or another device.

[0035] The energy of the bond promotion light L3 irradiated to each point on the printing surface PP in the second irradiation step S12b is set according to the two-dimensional refractive index distribution of the structure to be printed. Therefore, the two-dimensional energy distribution of the bond promotion light L3 is written in an area corresponding to the interior of the structure to be printed as a two-dimensional distribution of the proportion of dye bonded to the polymer P.

[0036] The second irradiation step S12b may be performed after the first irradiation step S12a, or the first irradiation step S12a may be performed after the second irradiation step S12b. When the former order is adopted, the two-dimensional energy distribution of the bond-promoting light L3 is written into the gel-like polymer P, and when the latter order is adopted, the two-dimensional energy distribution of the bond-promoting light L3 is written into the liquid monomer M. When the fluidity of the monomer M is low, either order may be adopted. When the fluidity of the monomer M is high, it is preferable to adopt the latter order.

[0037] The lifting process S12c is a process in which the lifting mechanism lifts the modeling table 12. Here, the direction in which the modeling table 12 is lifted is a direction in which the modeling table 12 moves away from the bottom plate of the container 11, and the amount by which the modeling table 12 is lifted is approximately equal to the thickness of one layer of the structure. The lifting mechanism may be controlled manually by an operator or automatically by the optical modeling apparatus 1 or another device.

[0038] In the pulling-up process S12c, the gel G consisting of the polymer P polymerized in the first irradiation process S12a of the current cycle is pulled up together with the modeling table 12, and the monomer M to be polymerized in the first irradiation process S12a of the next cycle is replenished around the modeling surface PP.

[0039] The structure formed by the exposure step S12, i.e., gel G containing a dye, is shown in the upper left of FIG. 3 . In FIG. 3 , white circles indicate dyes that are not bound to the polymer P constituting gel G (hereinafter also referred to as "unbound dyes"), and black circles indicate dyes that are bound to the polymer P constituting gel G (hereinafter also referred to as "bound dyes"). When the energy of the binding promotion light L3 is set independently for each of pillars P1 to P7, as shown in FIG. 3 , the proportion of bound dyes can be set independently for each of pillars P1 to P7. In the example shown in FIG. 3 , the proportion of bound dyes is relatively high in pillar P3 due to the relatively high energy of the binding promotion light L3 irradiated. Also, in the example shown in FIG. 3 , the proportion of bound dyes is relatively low in pillar P2 due to the relatively high energy of the binding promotion light L3 irradiated.

[0040] After the exposure step S12 is completed, the swelling step S13 is carried out. The swelling step S13 is a step of swelling (expanding by absorbing water) the structure formed in the exposure step S12, i.e., the gel G containing unbound and bound dyes. The structure swollen by the swelling step S13, i.e., the hydrogel HG containing unbound and bound dyes, is shown in the upper right of Figure 3. As shown in Figure 3, when the upper surfaces of pillars P1 to P2 are attached to the lower surface of substrate B, pillars P1 to P7 swell to increase their height while maintaining the area of ​​their upper surfaces.

[0041] After the swelling step S13 is completed, the washing step S14 is carried out. The washing step S14 is a step of removing unbound dye by washing from the structure swollen by the swelling step S13, i.e., the hydrogel HG containing unbound dye and bound dye. The structure from which the unbound dye has been removed by the washing step S14, i.e., the hydrogel HG containing bound dye, is shown in the middle left of Figure 3.

[0042] After the cleaning process S14 is completed, the deposition process S15 is performed. The deposition process S15 is a process of depositing refractive index adjusting particles with pre-bound dye as cores within the structure from which the unbound dye has been removed by the cleaning process S14, i.e., the hydrogel HG containing the pre-bound dye. The structure in which the refractive index adjusting particles have been formed by the deposition process S15, i.e., the hydrogel HG containing the refractive index adjusting particles, is shown in the middle right of Figure 3. In Figure 3, gray circles represent refractive index adjusting particles. In the example shown in Figure 3, the concentration of refractive index adjusting particles is relatively high in pillar P3, where the energy of the irradiated binding promotion light L3 is relatively high. Furthermore, in the example shown in Figure 3, the concentration of refractive index adjusting particles is relatively low in pillar P2, where the energy of the irradiated binding promotion light L3 is relatively low.

[0043] After the deposition step S15 is completed, the drying and shrinking step S16 is carried out. The drying and shrinking step S16 is a step of drying and shrinking (shrinking by drying) the structure on which the refractive index adjusting particles have been formed in the deposition step S15, i.e., the hydrogel HG containing the refractive index adjusting particles. The structure dried and shrunk in the drying and shrinking step S16, i.e., the structure made of the gel G containing the refractive index adjusting particles, is shown in the lower left of Figure 3.

[0044] According to the optical shaping method S1 of this embodiment, the thickness of the structure to be formed increases as the number of times that a point is irradiated with the polymerization-promoting light L1 in the first irradiation step S12a increases. Therefore, by setting the number of times that each point is irradiated with the polymerization-promoting light L1 in the first irradiation step S12a according to the thickness of the structure to be formed at that point, it is possible to form a structure having a desired two-dimensional thickness distribution.

[0045] Furthermore, according to the optical molding method S1 of this embodiment, the higher the energy of the bond promotion light L3 irradiated at a point in the second irradiation step S12b, the higher the refractive index of the structure to be molded (if the refractive index adjusting material particles have a refractive index increasing effect) or lower (if the refractive index adjusting material particles have a refractive index decreasing effect). Therefore, by setting the energy of the bond promotion light L3 irradiated at each point in the second irradiation step S12b according to the refractive index at that point of the structure to be molded, it is possible to mold a structure having a desired two-dimensional refractive index distribution.

[0046] Here, the number of times the polymerization-promoting light L1 is irradiated in the first irradiation step S12a and the energy of the bond-promoting light L3 irradiated in the second irradiation step S12b can be set independently of each other. Therefore, according to the optical shaping method S1 of this embodiment, the two-dimensional thickness and the two-dimensional refractive index distribution of the structure can be set independently of each other.

[0047] Furthermore, in the optical shaping method S1 according to this embodiment, the energy of the bond promotion light L3 irradiated to each point in the second irradiation step S12b can be set independently for each cycle, thereby enabling the fabrication of a structure in which the refractive index of each layer is set independently.

[0048] (Specific Example of Structure) By using the optical shaping method S1, it is possible to fabricate an optical diffraction element (a specific example of the above-mentioned "structure") having an optical calculation function, which is composed of a plurality of microcells whose thicknesses are set independently of one another. This is because the number of times that the polymerization promotion light L1 is irradiated in the first irradiation step S12a can be set independently for each cell.

[0049] When signal light is incident on such an optical diffraction element, the signal light beams with different phases that have passed through each microcell interfere with each other, thereby performing a predetermined optical calculation. In this specification, the term "microcell" refers to a cell with a cell size of less than 10 μm. In this specification, the term "cell size" refers to the square root of the cell area. For example, if the microcell has a square shape in plan view, the cell size is the length of one side of the cell. The lower limit of the cell size is not particularly limited, but is, for example, 1 nm.

[0050] A specific example of such an optical diffraction element (hereinafter referred to as "optical diffraction element 100") is shown in Fig. 4. Fig. 4 is a perspective view of the optical diffraction element 100.

[0051] The optical diffraction element 100 has a square effective area with sides of 1.0 mm. This effective area is composed of 100 x 100 microcells arranged in a matrix. Each microcell is composed of a rectangular pillar with a square base of 1 μm on a substrate with a thickness of 100 μm. The height of each pillar is, for example, 0 nm, 100 nm, 200 nm, ..., 1100 nm, or 1200 nm (13 levels in 100 nm steps). Signal light is incident on the effective area from a direction perpendicular to the effective area.

[0052] The two-dimensional refractive index distribution of the optical diffraction element 100 in a direction intersecting the incident direction of the signal light (in this embodiment, a direction perpendicular to the incident direction) is determined by the two-dimensional concentration distribution of the refractive index-adjusting particles in that direction. Furthermore, the one-dimensional refractive index distribution of the optical diffraction element 100 in a direction parallel to the incident direction of the signal light (in this embodiment, a direction parallel to the incident direction) is determined by the one-dimensional concentration distribution of the refractive index-adjusting particles in that direction. Therefore, by using the optical shaping method S1, it is possible to fabricate optical diffraction elements 100 having a variety of refractive index distributions.

[0053] 5A to 5D are partial cross-sectional views showing specific examples of the refractive index distribution of the optical diffraction element 100. In Fig. 5A to 5D, the refractive index at each point on the optical diffraction element 100 is expressed by the density of the hatching.

[0054] 5A shows an optical diffraction element 100 in which the refractive index is set for each cell. Such an optical diffraction element 100 can be fabricated by setting the energy of the binding promotion light L3 irradiated in the second irradiation step S12b for each cell.

[0055] Fig. 5B shows an optical diffraction element 100 in which the refractive index is set for each unit larger than a cell. In particular, Fig. 5B illustrates a case in which two cells are used as one unit. By setting the energy of the binding promotion light L3 irradiated in the second irradiation step S12b for each unit larger than a cell, such an optical diffraction element 100 can be fabricated.

[0056] 5C shows an optical diffraction element 100 in which the refractive index is set in units smaller than a cell. In particular, FIG. 5C illustrates a case in which one unit is a half cell. By setting the energy of the binding promotion light L3 irradiated in the second irradiation step S12b in units smaller than a cell, such an optical diffraction element 100 can be fabricated.

[0057] Figure 5(d) shows an optical diffraction element 100 in which the refractive index of each cell is set independently for each layer. In particular, Figure 5(d) illustrates a case in which the refractive index of each cell is set to gradually decrease with increasing distance from the substrate. For example, when using refractive index-adjusting particles that increase the refractive index, such an optical diffraction element 100 can be fabricated by gradually weakening the energy of the binding promotion light L3 irradiated in the second irradiation step S12b as the cycle progresses. In such an optical diffraction element 100, the change in refractive index at the interface between each cell and air (the upper surface of each pillar) is gradual, thereby suppressing unexpected reflection of signal light that may occur at that interface.

[0058] It should be noted that by arranging a plurality of optical diffraction elements, including the optical diffraction element 100, along the optical path of the signal light, it is possible to perform multi-stage optical calculations. An optical calculation device equipped with these plurality of optical diffraction elements can be used, for example, as an optical neural network.

[0059] (Summary) The method for manufacturing a structure according to Aspect 1 includes: a first irradiation step of irradiating a region of a modeling surface set between a bottom plate of the container and a modeling table, the region corresponding to the interior of the structure to be modeled, with polymerization-promoting light that promotes polymerization of a monomer stored in the container together with a dye; and a second irradiation step of irradiating the region with bonding-promoting light that promotes bonding of the dye to the monomer or the polymer obtained by the polymerization, while lifting the modeling table; an exposure step of repeating these steps; a swelling step of swelling the gel modeled by the exposure step; and a step of extracting from the hydrogel obtained by the swelling step the polymer bound to the polymer. The method includes a washing step of removing by washing unbound pigment, which is pigment that has not bound to the polymer, a deposition step of forming, by deposition, refractive index adjusting particles having a nucleus of the pigment bound to the polymer within the hydrogel obtained by the washing step, and a drying and shrinking step of drying and shrinking the hydrogel obtained by the deposition step, wherein the number of times that the polymerization promoting light is irradiated to each point in the first irradiation step is set according to the two-dimensional thickness distribution of the structure to be formed, and the energy of the binding promoting light irradiated to each point in the second irradiation step is set according to the two-dimensional refractive index distribution of the structure to be formed.

[0060] According to the above configuration, both the two-dimensional thickness distribution and the two-dimensional refractive index distribution of the structure to be manufactured can be set independently.

[0061] The method for manufacturing a structure according to aspect 2 is a method for manufacturing a structure according to aspect 1, wherein the structure is an optical diffraction element having a plurality of cells, which optically performs a predetermined calculation by causing signal light transmitted through each cell to interfere with each other, and the number of times that the polymerization promotion light is irradiated in the first irradiation step is set independently for each of the cells.

[0062] According to the above configuration, it is possible to independently set both the thickness and the two-dimensional refractive index distribution for each cell of the optical diffraction element to be formed.

[0063] A method for manufacturing a structure according to aspect 3 is the method for manufacturing a structure according to aspect 2, in which the energy of the bond-promoting light irradiated in the second irradiation step is set independently for each of the cells.

[0064] According to the above configuration, it is possible to independently set both the thickness and the refractive index of each cell of the optical diffraction element to be formed.

[0065] A method for manufacturing a structure according to aspect 4 is the method for manufacturing a structure according to aspect 2 or 3, in which the energy of the bond-promoting light irradiated in the second irradiation step is set independently for each cycle.

[0066] According to the above configuration, it is possible to independently set both the thickness of each cell and the refractive index of each layer of the optical diffraction element to be formed.

[0067] The optical modeling method of aspect 5 includes a first irradiation step of irradiating a region of a modeling surface set between the bottom plate of the container and the modeling table, which corresponds to the inside of the structure to be modeled, with polymerization promotion light that promotes polymerization of a monomer stored in a container together with a dye, and a second irradiation step of irradiating the region with bond promotion light that promotes bonding of the dye to the monomer or the polymer obtained by the polymerization, wherein the first irradiation step and the second irradiation step are repeated while the modeling table is lifted, and the number of times that the polymerization promotion light is irradiated to each point in the first irradiation step is set according to the two-dimensional thickness distribution of the structure to be modeled, and the energy of the bond promotion light irradiated to each point in the second irradiation step is set according to the two-dimensional refractive index distribution of the structure to be modeled.

[0068] According to the above configuration, both the two-dimensional thickness distribution and the two-dimensional refractive index distribution of the structure to be manufactured can be set independently.

[0069] The optical molding apparatus of aspect 6 comprises a first irradiation unit that irradiates a region of the molding surface set between the bottom plate of the container and the molding table, which corresponds to the inside of the structure to be molded, with polymerization promotion light that promotes polymerization of a monomer stored in a container together with a dye, and a second irradiation unit that irradiates the region with bond promotion light that promotes bonding of the dye to the monomer or the polymer obtained by the polymerization, wherein the irradiation of the polymerization promotion light by the first irradiation unit and the irradiation of the bond promotion light by the second irradiation unit are repeated while the molding table is lifted, the number of times that the first irradiation unit irradiates each point with the polymerization promotion light is set according to the two-dimensional thickness distribution of the structure to be molded, and the energy of the bond promotion light irradiated to each point in the second irradiation process is set according to the two-dimensional refractive index distribution of the structure to be molded.

[0070] According to the above configuration, it is possible to independently set both the two-dimensional thickness distribution and the two-dimensional refractive index distribution of the structure to be fabricated.

[0071] The optical diffraction element according to aspect 7 has a plurality of cells whose thicknesses are set independently of each other, and optically performs a predetermined calculation by causing signal light transmitted through each cell to interfere with each other. The optical diffraction element includes refractive index adjusting particles having a dye as a nucleus, and the two-dimensional refractive index distribution in a direction intersecting the direction of incidence of the signal light is determined according to the two-dimensional concentration distribution of the refractive index adjusting particles in that direction.

[0072] According to the above configuration, it is possible to independently set both the thickness and the two-dimensional refractive index distribution for each cell of the optical diffraction element to be formed.

[0073] An optical diffraction element according to an eighth aspect is the optical diffraction element according to the seventh aspect, in which the concentration of the refractive index adjusting particles is set independently for each of the cells.

[0074] According to the above configuration, it is possible to independently set both the thickness and the refractive index of each cell of the optical diffraction element to be formed.

[0075] The optical diffraction element of aspect 9 is the optical diffraction element of aspect 7 or 8, in which the one-dimensional refractive index distribution in a direction along the incident direction of the signal light is determined according to the one-dimensional concentration distribution of the refractive index adjusting particles in that direction.

[0076] According to the above configuration, it is possible to independently set both the thickness of each cell and the refractive index of each layer of the optical diffraction element to be formed.

[0077] The optical computing device according to aspect 10 includes a plurality of optical diffraction elements arranged on the optical path of the signal light, and the plurality of optical diffraction elements includes an optical diffraction element according to any one of aspects 7 to 9.

[0078] According to the above configuration, an optical arithmetic device with a high degree of freedom in the content of optical arithmetic can be realized.

[0079] (Summary 2) A method for manufacturing a structure according to aspect 1 of the present invention includes irradiating a region of a modeling surface set between a bottom plate of the container and a modeling table, the region corresponding to the interior of the structure to be modeled, with polymerization-promoting light that promotes polymerization of a monomer stored in a container together with a dye, wherein the number of times that the polymerization-promoting light is irradiated to each point on the modeling surface is set according to the two-dimensional thickness distribution of the structure, and irradiating the region with bond-promoting light that promotes bonding of the dye to the monomer or the polymer obtained by the polymerization, wherein the energy of the bond-promoting light irradiated to each point on the modeling surface is set according to the two-dimensional refractive index distribution of the structure. The method includes repeating the irradiation of the polymerization-promoting light, the irradiation of the bonding-promoting light, and the lifting of the modeling table, swelling the gel modeled by the repeated steps, removing by washing unbound dye that is not bound to the polymer from within the hydrogel obtained by swelling the gel, forming by deposition refractive index adjusting particles having the dye that is bound to the polymer as a nucleus within the hydrogel obtained by washing away the unbound dye, and drying and shrinking the hydrogel obtained by depositing the refractive index adjusting particles.

[0080] A method for manufacturing a structure according to aspect 2 of the present invention is a method for manufacturing a structure according to aspect 1, wherein the structure is an optical diffraction element having a plurality of cells, which optically performs calculations by causing signal light transmitted through each cell to interfere with each other, and the number of times the polymerization promotion light is irradiated is set independently for each cell.

[0081] A method for manufacturing a structure according to a third aspect of the present invention is the method for manufacturing a structure according to the second aspect, in which the energy of the bond-promoting light is set independently for each of the cells.

[0082] A method for manufacturing a structure according to a fourth aspect of the present invention is the method for manufacturing a structure according to the second aspect, in which the energy of the bond-promoting light is set independently for each cycle.

[0083] A fifth aspect of the present invention provides a photopolymerization method, comprising: irradiating a region of a modeling surface set between a bottom plate of the container and a modeling table with polymerization promotion light that promotes polymerization of a monomer stored in a container together with a dye, the region corresponding to the interior of the structure to be modeled; the number of times that the polymerization promotion light is irradiated to each point on the modeling surface is set according to the two-dimensional thickness distribution of the structure; irradiating the region with bond promotion light that promotes bonding of the dye to the monomer or the polymer obtained by the polymerization; the energy of the bond promotion light irradiated to each point on the modeling surface is set according to the two-dimensional refractive index distribution of the structure; and repeating the irradiation of the polymerization promotion light, the irradiation of the bond promotion light, and the lifting of the modeling table.

[0084] The optical molding apparatus of aspect 6 of the present invention comprises a first illuminator that irradiates a region of a molding surface set between the bottom plate of the container and the molding table with polymerization promotion light that promotes polymerization of a monomer stored in a container together with a dye, which corresponds to the inside of the structure to be molded, and a second illuminator that irradiates the region with bond promotion light that promotes bonding of the dye to the monomer or the polymer obtained by the polymerization, and repeats irradiation of the polymerization promotion light, irradiation of the bond promotion light, and lifting of the molding table, with the number of times that the first illuminator irradiates each point on the molding surface with the polymerization promotion light being set according to the two-dimensional thickness distribution of the structure, and the energy of the bond promotion light irradiated by the second illuminator to each point on the molding surface being set according to the two-dimensional refractive index distribution of the structure.

[0085] The optical diffraction element according to aspect 7 of the present invention comprises a plurality of cells each having a thickness set independently of one another, and refractive index adjusting particles having a dye as a nucleus, and performs calculations optically by causing the signal light beams transmitted through each cell to interfere with one another, and the two-dimensional refractive index distribution in a direction intersecting the direction of incidence of the signal light is determined according to the two-dimensional concentration distribution of the refractive index adjusting particles in that direction.

[0086] An optical diffraction element according to an eighth aspect of the present invention is the optical diffraction element according to the seventh aspect, wherein the concentration of the refractive index adjusting particles is set independently for each of the cells.

[0087] The optical diffraction element of aspect 9 of the present invention is the optical diffraction element of aspect 7, wherein the one-dimensional refractive index distribution in a direction along the incident direction of the signal light is determined according to the one-dimensional concentration distribution of the refractive index adjusting particles in that direction.

[0088] An optical computing device according to a tenth aspect of the present invention includes a plurality of optical diffraction elements arranged on an optical path of signal light, and the plurality of optical diffraction elements includes the optical diffraction element according to the seventh aspect.

[0089] (Additional Notes) The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the above-described embodiments are also included in the technical scope of the present invention.

[0090] REFERENCE SIGNS LIST 1 Optical molding device 11 Container 12 Molding table 13 First irradiation unit 14 Second irradiation unit L1 Polymerization promotion light L2 Polymerization inhibition light L3 Bonding promotion light

Claims

1. A method for manufacturing a hydrogel includes: a first irradiation step of irradiating a region of a modeling surface set between a bottom plate of the container and a modeling table, the region corresponding to the inside of a structure to be modeled, with polymerization-promoting light for promoting polymerization of a monomer stored in the container together with a dye; and a second irradiation step of irradiating the region with binding-promoting light for promoting binding of the dye to the monomer or the polymer obtained by the polymerization; an exposure step of repeating these steps while lifting up the modeling table; a swelling step of swelling a gel modeled by the exposure step; a cleaning step of removing, by cleaning, unbound dye, which is a dye that is not bound to the polymer, from within the hydrogel obtained by the swelling step; a deposition step of depositing, within the hydrogel obtained by the cleaning step, refractive index adjusting particles having a nucleus of the dye bound to the polymer; and a drying and shrinking step of drying and shrinking the hydrogel obtained by the deposition step; wherein the number of times that the polymerization-promoting light is irradiated to each point in the first irradiation step is set according to the two-dimensional thickness distribution of the structure to be modeled; a bond-promoting light beam having energy irradiated to each point in the second irradiation step, the bond-promoting light beam being set in accordance with a two-dimensional refractive index distribution of the structure to be fabricated.

2. The method for manufacturing a structure according to claim 1, wherein the structure is an optical diffraction element having a plurality of cells and optically performing a predetermined calculation by causing signal light transmitted through each cell to interfere with each other, and the number of times the polymerization promotion light is irradiated in the first irradiation step is set independently for each of the cells.

3. The method for manufacturing a structure according to claim 2, wherein the energy of the bond-promoting light irradiated in the second irradiation step is set independently for each of the cells.

4. The method for manufacturing a structure according to claim 2 or 3, wherein the energy of the bond-promoting light irradiated in the second irradiation step is set independently for each cycle.

5. A photopolymerization method comprising: a first irradiation step of irradiating a region of a printing surface set between a bottom plate of the container and a printing table, the region corresponding to the inside of a structure to be printed, with polymerization-promoting light that promotes polymerization of a monomer stored in a container together with a dye; and a second irradiation step of irradiating the region with bond-promoting light that promotes bonding of the dye to the monomer or to the polymer obtained by the polymerization, wherein the first irradiation step and the second irradiation step are repeated while lifting the printing table; the number of times that the polymerization-promoting light is irradiated to each point in the first irradiation step is set according to the two-dimensional thickness distribution of the structure to be printed; and the energy of the bond-promoting light irradiated to each point in the second irradiation step is set according to the two-dimensional refractive index distribution of the structure to be printed.

6. A photopolymerization device comprising: a first irradiation unit that irradiates a region of a printing surface set between a bottom plate of the container and a printing table, the region corresponding to the inside of a structure to be printed, with polymerization promotion light that promotes polymerization of a monomer stored in a container together with a dye; and a second irradiation unit that irradiates the region with bond promotion light that promotes bonding of the dye to the monomer or to a polymer obtained by the polymerization; wherein the irradiation of the polymerization promotion light by the first irradiation unit and the irradiation of the bond promotion light by the second irradiation unit are repeated while the printing table is lifted; the number of times that the first irradiation unit irradiates each point with the polymerization promotion light is set according to the two-dimensional thickness distribution of the structure to be printed; and the energy of the bond promotion light irradiated to each point by the second irradiation unit is set according to the two-dimensional refractive index distribution of the structure to be printed.

7. An optical diffraction element having a plurality of cells whose thicknesses are set independently of each other, and optically executing a predetermined calculation by causing signal light transmitted through each cell to interfere with each other, the optical diffraction element including refractive index adjusting particles having a dye as a nucleus, and a two-dimensional refractive index distribution in a direction intersecting the direction of incidence of the signal light being determined according to a two-dimensional concentration distribution of the refractive index adjusting particles in that direction.

8. The optical diffraction element according to claim 7, wherein the concentration of the refractive index adjusting particles is set independently for each of the cells.

9. The optical diffraction element according to claim 7 or 8, wherein a one-dimensional refractive index distribution in a direction parallel to the incident direction of the signal light is determined according to a one-dimensional concentration distribution of the refractive index adjusting particles in that direction.

10. An optical computing device comprising a plurality of optical diffraction elements arranged on an optical path of a signal light, the plurality of optical diffraction elements including an optical diffraction element according to any one of claims 7 to 9.

Images