Optical computing device and method for manufacturing the same

Abstract

Implement an optical operation device that can easily maintain the relative positional relationship of planar optical diffraction elements in a desired relationship. The optical operation device (1) includes: an optical diffraction element group (11) and a cylindrical body (12). The optical diffraction element group (11) includes a plurality of planar optical diffraction elements (11a1 to 11a6) made of a photocurable resin. The cylindrical body (12) houses the optical diffraction element group (11). At least a part of the outer edge of each planar optical diffraction element (11ai) constituting the optical diffraction element group (11) is fixed to the inner side surface of the cylindrical body (12).

Description

Technical Field

[0001] The present invention relates to an optical arithmetic device including a plurality of planar optical diffraction elements. Further, it relates to a method for manufacturing such an optical arithmetic device. Background Art

[0002] Patent Document 1 discloses a technique in which a plurality of optical elements such as lenses and filters are arranged on the optical path of input light, and these optical elements act on the input light in sequence.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: International Publication No. 2013 / 027340 Summary of the Invention

[0006] (1) Technical Problem to be Solved

[0007] In an optical arithmetic device in which a plurality of planar optical diffraction elements are arranged and these planar optical diffraction elements act on input light in sequence, it is important to maintain the relative positional relationship of the plurality of planar optical diffraction elements as a desired relationship. The reason is that if the relative positional relationship of the planar optical diffraction elements deviates from the desired relationship, it becomes difficult to exert a desired action on the input light.

[0008] As an example, a planar optical diffraction element is known which is designed to have a plurality of micro-units with individually set refractive indices, and the light passing through each micro-unit interferes with each other, so that a predetermined arithmetic operation can be optically performed in a space-saving and low-power consumption manner. In an optical arithmetic device composed of such planar optical diffraction elements, even if the deviation of the relative positional relationship of the planar optical diffraction elements is on the order of nm, it may be difficult to perform a desired optical arithmetic operation.

[0009] One aspect of the present invention is achieved in view of the above problems, and realizes an optical arithmetic device in which it is easy to maintain the relative positional relationship of planar optical diffraction elements as a desired relationship.

[0010] (2) Technical Solution

[0011] An optical arithmetic device according to one aspect of the present invention includes: an optical diffraction element group including a plurality of planar optical diffraction elements made of a photocurable resin; and a cylindrical body that houses the optical diffraction element group, and at least a part of the outer edge of each planar optical diffraction element constituting the optical diffraction element group is fixed to the inner side surface of the cylindrical body.

[0012] A method for manufacturing an optical arithmetic device according to one aspect of the present invention is a method for manufacturing the optical arithmetic device according to the above aspect, and includes a molding step of integrally molding the optical diffraction element group inside the cylindrical body.

[0013] (III) Advantageous Effects

[0014] According to one aspect of the present invention, an optical arithmetic device can be realized, which can easily maintain the relative positional relationship of the planar optical diffraction element as a desired relationship. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a perspective view showing the structure of the optical arithmetic device according to Embodiment 1 of the present invention.

[0016] Figure 2 It shows Figure 1 a perspective view of a specific example of the planar optical diffraction element included in the optical arithmetic device.

[0017] Figure 3 It shows Figure 1 a perspective view of a modified form of the optical diffraction element group included in the optical arithmetic device.

[0018] Figure 4 It schematically shows Figure 1 the first manufacturing method of the multilayer optical diffraction element 1.

[0019] Figure 5 It schematically shows Figure 1 the second manufacturing method of the multilayer optical diffraction element 1.

[0020] Figure 6 It is a cross-sectional view showing the structure of the optical arithmetic device according to Embodiment 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] (Embodiment 1)

[0022] With reference to Figure 1 the structure of the optical arithmetic device 1 according to one embodiment of the present invention will be described. Figure 1 It is a perspective view showing the structure of the optical arithmetic device 1.

[0023] The optical arithmetic device 1 includes: an optical diffraction element group 11, a cylinder 12, and bolts 13a and 13b.

[0024] The optical diffraction element group 11 is a set of N planar optical diffraction elements 11a1 to 11aN made of a photocurable resin. Although Figure 1 an optical diffraction element group composed of six planar optical diffraction elements 11a1 to 11a6 is exemplified, the number N of the planar optical diffraction elements 11a1 to 11aN is not limited to six, and any natural number of 2 or more is sufficient.

[0025] In the present embodiment, the shape of each planar light diffraction element 11ai (i is a natural number from 1 to N) is a disk shape (a cylindrical shape with a relatively low height). The planar light diffraction elements 11a1 to 11aN are arranged such that the central axes of the respective planar light diffraction elements 11ai coincide, and the upper surface of each planar light diffraction element 11aj (j is a natural number from 1 to N - 1) faces the lower surface of the adjacent planar light diffraction element 11aj+1.

[0026] In addition, in the present embodiment, it is designed such that each planar light diffraction element 11ai has a plurality of micro-units with individually set refractive indices in the effective region, and the light transmitted through each micro-unit (presumably mainly visible light) interferes with each other to perform a predetermined optical operation. When the planar light diffraction elements 11a1 to 11aN are arranged and the optical operation is performed N times in sequence, it is important to maintain the relative positional relationship of the planar light diffraction elements 11a1 to 11aN as a desired relationship. In addition, in the present specification, a "micro-unit" refers to a unit with a size of less than or equal to the micron level, that is, less than 10 μm. The lower limit of the micro-unit size is not particularly limited, for example, it is 1 nm.

[0027] In addition, in the present embodiment, the light diffraction element group 11 has N - 1 columns 11b1 to 11bN - 1 made of a photocurable resin. Each column 11bj is a structure for connecting adjacent planar light diffraction elements 11aj and 11aj+1 outside the effective region. Thereby, it is easy to maintain the relative positional relationship in the arrangement direction of the planar light diffraction elements 11a1 to 11aN as a desired relationship.

[0028] The cylindrical body 12 is a component for accommodating the light diffraction element group 11. At least a part of the outer edge of each planar light diffraction element constituting the light diffraction element group 11 is fixed to the inner side surface of the cylindrical body 12. Thereby, it is easy to maintain the relative positional relationship in the arrangement direction of the planar light diffraction elements 11a to 11aN as a desired relationship. The upper end of the cylindrical body 12 is closed by a plug 13a, and the lower end of the cylindrical body 12 is closed by a plug 13b. The plug 13a is made of a transparent material that allows the light output from the light diffraction element group 11 to pass through. In order to suppress the optical influence of the plug 13a on the light output from the light diffraction element group 11 to a small level, it is preferable that the upper surface and the lower surface of the plug 13a are flat and parallel to the upper surface of the planar light diffraction element 11a6. In addition, the plug 13b is made of a transparent material that allows the light input to the light diffraction element group 11 to pass through. In order to suppress the optical influence of the plug 13b on the light input to the light diffraction element group 11 to a small level, it is preferable that the upper surface and the lower surface of the plug 13b are flat and parallel to the lower surface of the planar light diffraction element 11a1.

[0029] In the present embodiment, the shape of the cylinder 12 is cylindrical. The inner diameter of the cylinder 12 is consistent with the outer diameter of each planar light diffraction element 11ai, and the outer edge of each planar light diffraction element 11ai can be fixed to the inner side surface of the cylinder 12. Therefore, even if the light diffraction element group 11 undergoes thermal expansion, stress will be uniformly applied to the outer edge of each planar light diffraction element 11ai, thereby reducing the possibility of the following problems: undesirable deformation of each planar light diffraction element 11ai; and changes in the relative positional relationship of the planar light diffraction elements 11a1 to 11aN.

[0030] In addition, the cylinder 12 is preferably made of a material having a larger Young's modulus than the light diffraction element group 11. Thus, compared with a case where the light diffraction element group 11 is not housed in the cylinder 12 but is exposed, an optical computing device 1 can be realized in which the relative positional relationship of the planar light diffraction elements 11a1 to 11aN is less likely to change when an external force acts.

[0031] In addition, the cylinder 12 is preferably made of a material having a smaller thermal expansion coefficient than the optical diffraction element group 11. Thus, compared with a case where the optical diffraction element group 11 is not housed in the cylinder 12 but is exposed, an optical computing device 1 can be realized in which the relative positional relationship of the planar optical diffraction elements 11a1 to 11aN is less likely to change when the temperature changes.

[0032] In addition, the cylinder 12 is preferably made of a material that transmits the light used to cure the photocurable resin constituting the light diffraction element group 11 (for example, ultraviolet light when the photocurable resin is an ultraviolet curable resin). This is because the light diffraction element group 11 can be formed inside the cylinder 12 even by irradiation with light from the side. In addition, as a material having a Young's modulus of elasticity greater than that of the photocurable resin and a thermal expansion coefficient smaller than that of the photocurable resin and being transparent to the light that cures the photocurable resin, for example, quartz glass can be cited.

[0033] In addition, it is preferable to fill oil inside the cylinder 12. Thereby, (1) foreign substances (including moisture) are less likely to invade the inside of the cylinder 12; (2) vibration of the planar light diffraction elements 11a1 to 11aN can be suppressed; (3) aging (such as oxidation) of each planar light diffraction element 11ai can be suppressed. In addition, when the refractive index of the oil is greater than 1 and less than the refractive index of the planar light diffraction element 11ai, (4) reflection that may occur at the interface between air and each planar light diffraction element 11ai can also be reduced. The type of oil is not particularly limited, but silicone-based or paraffin-based oils are excellent in terms of stability and availability. The oil can be acrylic, epoxy, vinyl, rubber, polyurethane, methacrylic, nylon, bisphenol, glycol, polyimide, fluorinated acrylic, fluorinated epoxy, or a combination of these polymer materials. In addition, it is not necessary to fill oil. Even if a liquid or solid having a refractive index similar to that of the oil is filled instead of the oil, the same effect as when filling oil can be obtained. As an example of the solid filled instead of the oil, for example, a photocurable resin having a refractive index different from that of the photocurable resin constituting the light diffraction element group 11 can be cited. In addition, in order to appropriately refract the light passing through each unit of the planar light diffraction element 11ai according to the height of the unit, it is preferable that the difference between the refractive index of the material of the planar light diffraction element 11ai and the refractive index of the liquid or solid filled inside the cylinder 12 is 0.5 or more and 1.5 or less. In addition, gases such as oxygen or nitrogen can be sealed instead of the oil. In addition, when only air fills the inside of the cylinder 12, the plugs 13a and 13b can be omitted.

[0034] (Specific example of planar light diffraction element)

[0035] Refer to Figure 2 A specific example of the planar light diffraction element 11ai included in the optical arithmetic device 1 will be described. Figure 2 It is a perspective view showing the effective region of the planar light diffraction element 11ai of this specific example.

[0036] The effective region of the planar light diffraction element 11ai of this specific example is a square with a side length of 1.0 mm and is composed of 100×100 micro-units arranged in a matrix. Each micro-unit is composed of columns formed on a substrate with a thickness of 100 μm and having a bottom side with a side length of 1 μm. The height of each column is any one of 0 nm, 100 nm, 200 nm, …, 1100 nm, 1200 nm (13 stages with a 100 nm step), and the refractive index of the micro-unit composed of the column is determined to be the desired refractive index.

[0037] In addition, regarding the cell size of the planar light diffraction element 11ai, although it is 1 μm in this specific example, it is not limited thereto. That is, the cell size of the planar light diffraction element 11ai only needs to be less than 10 μm. In addition, the number of cells and the effective area size of the planar light diffraction element 11ai are also arbitrary.

[0038] (Modification example of the light diffraction element group)

[0039] In the present embodiment, as shown in (a) of Figure 3 , as a structure for connecting adjacent planar light diffraction elements 11aj and 11aj+1 to each other, a plurality of cylindrical columns 11bi arranged outside the effective area are employed, but the present invention is not limited thereto.

[0040] For example, as shown in (b) of Figure 3 , as a structure for connecting adjacent planar light diffraction elements 11aj and 11aj+1 to each other, a single cylindrical column 11ci surrounding the effective area may be employed. Thereby, the relative positional relationship between adjacent planar light diffraction elements 11aj and 11aj+1 can be more reliably maintained. In addition, in this case, it is preferable to provide an opening 11di in each column 11ci. Thereby, when shaping the light diffraction element group 11, the ultraviolet curable resin remaining inside the column 11ci can be discharged, and a cleaning liquid or a developing liquid can be injected into the column 11ci or the cleaning liquid and the developing liquid can be discharged from the inside of the column 11ci.

[0041] (First manufacturing method of the optical computing device)

[0042] Refer to Figure 4 to describe the first manufacturing method S1 of the optical computing device 1. Figure 4 is a diagram schematically showing the first manufacturing method S1 of the optical computing device 1. In addition, in the first manufacturing method S1 of the optical computing device 1, a lifting rod 2 provided with a disk portion 21 is used, and the outer diameter of the disk portion 21 is the same as or substantially the same as the inner diameter of the cylinder 12. It is also set that the light diffraction element group 11 is made of an ultraviolet curable resin.

[0043] First, perform a preparation process S11. In the preparation process S11, the lifting rod 2 is inserted into the inside of the cylinder 12 from above with the disk portion 21 facing downward, and then the lower end of the cylinder 12 is immersed in the uncured ultraviolet curable resin contained in the small pool 3 made of a material that allows ultraviolet rays to pass through.

[0044] Next, a light diffraction element shaping process S12 and a column shaping process S13 (an example of the "shaping process" in the claims) are performed. In the light diffraction element shaping process S12, while slowly lifting the lifting rod 2, ultraviolet rays are irradiated onto the ultraviolet curable resin inside the cylinder 12 from below the cylinder 12, thereby shaping the planar light diffraction element 11a1. In the column shaping process S13, while slowly lifting the lifting rod 2, ultraviolet rays are irradiated onto the ultraviolet curable resin inside the cylinder 12 from below the cylinder 12, thereby shaping the column 11b1. In addition, for the ultraviolet irradiation in the light diffraction element shaping process S12 and the column shaping process S13, it can be performed in the SLA (Stereo Lithography) method or the DLP (Digital Light Processing) method.

[0045] Next, the light diffraction element shaping process S12 and the column shaping process S13 are repeatedly executed to integrally shape the light diffraction element group 11 composed of the planar light diffraction elements 11a2 to 11aN and the columns 11b2 to 11bN - 1. In addition, after the shaping of the planar light diffraction elements 11a1 to 11aN and the columns 11b1 to 11bN - 1 is completed, the fixing process can be performed by irradiating ultraviolet rays from the side of the cylinder 12 to fix the outer edges of the respective planar light diffraction elements 11ai to the inner side surface of the cylinder 12.

[0046] Next, the circular plate portion 21 is separated from the planar light diffraction element 11a1 and the lifting rod 2 is pulled out from the cylinder 12, and the cylinder 12 in which the light diffraction element group 11 is formed inside is lifted from the pool 3. And a developing / cleaning process S14 (an example of the "discharging process" in the claims) is performed. In the developing / cleaning process S14, a developing solution is injected into the cylinder 12 for developing treatment, and a cleaning solution is injected into the cylinder 12 for cleaning treatment. Through this developing treatment and / or cleaning treatment, the uncured ultraviolet curable resin remaining between the adjacent planar light diffraction elements 11aj and 11aj + 1 can be discharged through the above-mentioned through holes. In addition, when an ultraviolet curable resin that does not require development is used, the developing treatment can be omitted.

[0047] Finally, an oil filling process S15 is performed. In the oil filling process S15, oil is filled into the cylinder 12, and the upper end and the lower end of the cylinder 12 are closed by the plugs 13a and 13b. Thus, the optical computing device 1 is completed.

[0048] In addition, it is preferable to provide through-holes outside the effective regions of the planar light diffraction elements 11ai. Thereby, it becomes easy to discharge the uncured ultraviolet curable resin remaining between adjacent planar light diffraction elements 11aj and 11aj+1, and it becomes easy to inject and discharge the developing solution or the cleaning solution.

[0049] As described above, the first manufacturing method S1 is a manufacturing method of the optical arithmetic device 1, which immerses the lower end of the cylindrical body 12 in the uncured photocurable resin, and irradiates light from below while lifting the cured part of the light diffraction element group 11 upward, thereby successively shaping the light diffraction element group 11 inside the cylindrical body 12. Therefore, according to the first manufacturing method S1, it is possible to integrally shape the light diffraction element group 11 in which the relative positional relationship of the planar light diffraction elements 11a1 to 11aN is the desired relationship inside the cylindrical body 12. In addition, according to the first manufacturing method S1, the light diffraction element group 11 is shaped using ultraviolet rays, so the time required for shaping can be shortened compared with the case of shaping the light diffraction element group 11 using electron beams. In addition, according to the above manufacturing method S1, it is not necessary to discard the uncured ultraviolet curable resin, so the raw material cost can be suppressed.

[0050] In addition, according to the first manufacturing method S1, for each planar light diffraction element 11ai, the base and the micro units are formed of the same photocurable resin. Therefore, compared with the case where the micro units are formed of a material different from the base, the bonding strength between the micro units and the base is increased. For example, when micro units of a photocurable resin are formed on a glass base, the micro units may peel off from the base when the uncured photocurable resin is being cleaned or the like. In contrast, in the present embodiment where both are integrally formed of the same material, the bonding force between the micro units and the base is strong, and the effect that the micro units are less likely to peel off from the base can be obtained.

[0051] If the number of micro units peeled off from the base increases, the properties of the light may change due to a change in the optical path length of the diffracted light or a change in the diffraction angle, etc., and the arithmetic accuracy may be reduced. However, in the optical arithmetic device 1 manufactured by the manufacturing method of the present embodiment, the micro units are less likely to peel off from the base, so the possibility of the above problems occurring can be further reduced.

[0052] (Second manufacturing method of the optical arithmetic device)

[0053] Refer to Figure 5 A description will be given of the second manufacturing method S2 of the optical arithmetic device 1. Figure 5 FIG. is a diagram schematically showing the second manufacturing method S2 of the optical arithmetic device 1. In addition, in the second manufacturing method S2 of the optical arithmetic device 1, the optical arithmetic device 1 is manufactured without using the pool 3.

[0054] First, perform the preparation process S21. In the preparation process S21, the lower end of the cylinder 12 is sealed with the bolt 13a, the lifting rod 2 is inserted into the cylinder 12 from above with the circular plate portion 21 facing downward, and then an ultraviolet curable resin is injected into the cylinder 12. The injected ultraviolet curable resin also enters the lower side of the circular plate portion 21 through a through hole (not shown) that penetrates the circular plate portion 21 vertically.

[0055] Next, perform the optical diffraction element shaping process S22 and the column shaping process S23. In the optical diffraction element shaping process S22, while slowly lifting the lifting rod 2, ultraviolet light is irradiated onto the ultraviolet curable resin inside the cylinder 12 from below the cylinder 12 to shape the planar optical diffraction element 11a1. In the column shaping process S23, while slowly lifting the lifting rod 2, ultraviolet light is irradiated onto the ultraviolet curable resin inside the cylinder 12 from below the cylinder 12 to shape the column 11b1. In addition, for the ultraviolet irradiation in the optical diffraction element shaping process S22 and the column shaping process S23, it can be performed in the SLA (Stereo Lithography) method or the DLP (Digital Light Processing) method.

[0056] Next, repeat the optical diffraction element shaping process S22 and the column shaping process S23 to shape the planar optical diffraction elements 11a2 - 11aN and the columns 11b2 - 11bN - 1. In addition, after the shaping of the planar optical diffraction elements 11a1 - 11aN and the columns 11b1 - 11bN - 1 is completed, ultraviolet light can be irradiated from the side of the cylinder 12 to fix the outer edges of the respective planar optical diffraction elements 11ai to the inner side surface of the cylinder 12.

[0057] Next, separate the circular plate portion 21 from the planar optical diffraction element 11a1, pull out the lifting rod 2 from the cylinder 12, and discharge the ultraviolet curable resin remaining inside the cylinder 12. Then, perform the development / cleaning process S24. In the development / cleaning process S24, a developer is injected into the cylinder 12 for development processing, and a cleaning liquid is injected into the cylinder 12 for cleaning processing. In addition, when an ultraviolet curable resin that does not require development is used, the development processing can be omitted.

[0058] Finally, perform the oil filling process S25. In the oil filling process S25, oil is filled into the cylinder 12, and the upper end of the cylinder 12 is sealed with the bolt 13b. Thus, the optical computing device 1 is completed.

[0059] According to the second manufacturing method S2, the optical computing device 1 can be manufactured using less ultraviolet curable resin compared to the first manufacturing method S1. Therefore, according to the second manufacturing method S2, the raw material cost can be further reduced compared to the first manufacturing method S1.

[0060] In addition, in this manufacturing method, the substrate and the micro-units are integrally formed of the same material, so the effect that the micro-units are less likely to peel off from the substrate can be obtained.

[0061] (Embodiment 2)

[0062] Next, the optical computing device 1A according to Embodiment 2 of the present invention will be described with reference to the drawings. In addition, the same reference numerals are assigned to the same elements as those of the optical computing device 1 in Embodiment 1, and the detailed description thereof is omitted. The light incident on the optical computing device 1A is infrared light (especially near-infrared light). First, the reason for using infrared light as the incident light will be described.

[0063] The incident light incident on the optical computing device 1A forms an image on an image plane at a predetermined distance from the last-stage planar light diffraction element 11a6. The distance to this image plane is a value determined by a multiple of the incident light wavelength from the last-stage planar light diffraction element 11a6. In addition, the light incident on each planar light diffraction element 11ai needs to be parallel light. Considering the light diffusion caused by the divergence angle of the light, the shorter the distance to the image plane separated by a multiple of the wavelength, the better. However, if the distance to the image plane is short, it is difficult to perform manufacturing including positioning. Considering the above conditions, the longer the wavelength of the light incident on the optical computing device 1A, the better. For example, infrared light is preferred compared to visible light. This is the reason for using infrared light as the light incident on the optical computing device 1A.

[0064] Figure 6 FIG. is a cross-sectional view showing the structure of the optical computing device 1A according to Embodiment 2 of the present invention. Instead of the plug 13b on the light exit side of the optical computing device 1 in Embodiment 1, the optical computing device 1A includes: a light conversion layer 31, a light diffusion layer 32, and a spacer 40. The structure other than this is the same as the structure of the optical computing device 1.

[0065] The light conversion layer 31 and the light diffusion layer 32 are disk-shaped members provided in a direction substantially orthogonal to the incident direction of the infrared light. The shapes of the light conversion layer 31 and the light diffusion layer 32 are not particularly limited, but in the present embodiment, they match the shape of the planar light diffraction element 11ai. The spacer 40 is a member that supports the light conversion layer 31 and the light diffusion layer 32 at the outer peripheral portion. In Figure 6 the incident direction of the infrared light is indicated by an arrow D.

[0066] The light conversion layer 31 is a layer that shortens the wavelength of infrared rays and converts them into visible light, and is disposed at the final stage of the optical arithmetic device 1A. The final stage is the stage at which the light incident on the optical arithmetic device 1A is emitted, and in the present embodiment, it is the stage subsequent to the planar light diffraction element 11a6. The light conversion layer 31 converts the infrared rays emitted from the planar light diffraction element 11a6 into visible light.

[0067] For the light conversion layer 31, for example, a method of forming by surface modification of nanoparticles is known. For example, nanoparticles doped with rare earth ions on the surface of a dielectric such as an inorganic fluoride or an inorganic oxide can be used. In addition, the light conversion layer 31 can also be formed, for example, by a method of forming an organic dye by complexing rare earth ions. The conversion efficiency of converting infrared rays into visible light by this method is relatively high.

[0068] The reason why the optical arithmetic device 1A includes the light conversion layer 31 is as follows. A high-precision camera that captures infrared rays, for example, requires an imaging element using an InGaAs sensor, which is expensive. Therefore, the following method can be considered: the light passing through the optical arithmetic device 1A uses infrared rays, the infrared rays passing through the optical arithmetic device 1A are converted into visible light, and a visible light camera is used for imaging. Because if it is visible light, imaging can be performed using an inexpensive CMOS sensor for visible light. The light conversion layer 31 is a wavelength conversion element for enabling the light emitted from the optical arithmetic device 1A to be detected by a visible light camera.

[0069] The light that has passed through the planar light diffraction element 11a6 (hereinafter also referred to as transmitted light) is captured by a camera, for example, after passing through a lens. The transmitted light contains components with various traveling directions, and in some cases, a part of the components are vignetted by the lens. Therefore, it is preferable to use the diffusion layer 32 to change the traveling directions of the components vignetted by the lens in the transmitted light, and increase the components incident on the camera (equivalent to reducing the numerical aperture of the transmitted light or increasing the effective numerical aperture of the lens). That is to say, the diffusion layer 32 has the following functions: diffusing the visible light generated by the light conversion layer 31, increasing the components not vignetted by the lens, and guiding more light into the camera. In other words, the physical limitations of the lens can be avoided by using the diffusion layer 32. The structure of the diffusion layer 32 is not limited as long as it has the function of diffusing light. For example, it is a structure formed by roughening one surface of a quartz plate. The methods for roughening the surface of the quartz plate include mechanical methods such as sandblasting, or chemical methods such as coating an etching solution. Regarding the degree of roughening, for example, for a structure in which fine particles are dispersed on the surface, as the particle size of the fine particles, it is preferably about 80 to 250. In addition, regarding the diffusion angle of light, it is preferably between 10° and 80°, and more preferably a relatively wide diffusion angle of 60° to 80°. Furthermore, if the roughening is too deep, the light diffuses in the depth direction (the traveling direction of light) and blurs the image. Therefore, it is preferable that the roughening is limited to the surface of the quartz plate. That is to say, the layer having the diffusion function is preferably thin.

[0070] The spacer 40 defines the distance L from the planar light diffraction element 11a6 at the last stage of the optical arithmetic device 1A to the diffusion layer 32. Strictly speaking, the distance L is the distance from the highest position of the micro unit of the planar light diffraction element 11a6 to the diffusion layer 32. Since the maximum height of the micro unit is about 1200 nm (1.2 μm), the height of the micro unit can be ignored. For example, when the thickness of the light conversion layer 31 is x, the height (the length in the infrared traveling direction) of the spacer 40 is set to (L - x). Specifically, when the incident infrared ray is a near-infrared ray of 1550 nm, the distance L can be, for example, 60 μm. For example, by disposing the spacer 40 (with a height of L - x) manufactured as a monomer on the planar light diffraction element 11a6, and sequentially disposing the light conversion layer 31 (with a thickness of x) and the diffusion layer 32 on the spacer 40, the distance L from the planar light diffraction element 11a6 to the diffusion layer 32 can be accurately defined. Regarding the spacer 40, it can be formed by arranging cylindrical bodies similar to the column 11bi in a circular ring shape, or it can also be formed into a circular ring shape.

[0071] In the above-described optical operation device 1A, the light conversion layer 31 is on the light incident side, and the diffusion layer 32 is on the light emission side. However, the order of the light conversion layer 31 and the diffusion layer 32 is not limited to this, and the opposite configuration (not shown) is also possible. In this case, the infrared rays emitted from the planar light diffraction element 11a6 first enter the diffusion layer 32 and are diffused, and the diffused infrared rays enter the light conversion layer 31 and are converted into visible light.

[0072] (Manufacturing method)

[0073] Next, the manufacturing method of the optical operation device 1A will be described. The manufacturing method of the optical operation device 1A is the same as the steps of the first manufacturing method S1 of the optical operation device 1 up to the development / cleaning step S14. After that, the spacer 40 is formed, and the previously manufactured light conversion layer 31 and diffusion layer 32 are sequentially stacked on the spacer 40. In addition, the spacer 40 can also be formed on the planar light diffraction element 11a6 using an ultraviolet curable resin by the same method as the manufacturing method of the column 11bi. By manufacturing the spacer 40 by the same method as the manufacturing method of the column 11bi, the dimensional accuracy of the distance L can be further improved.

[0074] Alternatively, a light conversion unit in which the spacer 40, the light conversion layer 31, and the diffusion layer 32 are sequentially stacked can be manufactured in advance, and the light conversion unit can be stacked on the planar light diffraction element 11a6 after the development / cleaning step S14 of the manufacturing method S1.

[0075] (Modification 1)

[0076] The optical operation device 1A is configured such that the spacer 40, the light conversion layer 31, and the diffusion layer 32 are separate elements. However, as in the case of the optical operation device 1B shown in Figure 6 , in order to define the distance L with as high dimensional accuracy as possible, the spacer 40 and the diffusion layer 32 are configured to be integrated.

[0077] The optical operation device 1B includes: a spacer 40 and a light conversion layer 31. The spacer 40 includes: legs 401 provided in the light incident direction at the outer peripheral portion, and a disc-shaped plate portion 402. The diffusion layer 32 is formed on the incident-side surface of the plate portion 402. The light conversion layer 31 is stacked on the emission-side surface of the plate portion 402. The legs 401 define the distance L between the planar light diffraction element 11a6 and the diffusion layer 32. That is, the height (length in the light incident direction) of the legs 401 is L. In this modification, the order of the light conversion layer 31 and the diffusion layer 32 can also be switched.

[0078] The spacer 40 is formed of quartz, for example, and the diffusion layer 32 is formed by roughening the incident-side surface of the plate portion 402. In addition, since the spacer 40 is made of quartz, the height L of the leg portion 401 can be formed with high dimensional accuracy. That is, by forming a part of the spacer 40 as the diffusion layer 32, the distance L between the planar light diffraction element 11a6 and the diffusion layer 32 can be defined with high dimensional accuracy.

[0079] Regarding the manufacturing method of the optical arithmetic device 1B, it is sufficient to dispose the pre-fabricated spacer 40 and the light conversion layer 31 on the planar light diffraction element 11a6 after the development / washing process S14 of the first manufacturing method S1 of the optical arithmetic device 1.

[0080] (Modification 2)

[0081] In the optical arithmetic devices 1A and 1B, the diffusion layer 32 does not have to be formed over the entire surface of the disk-shaped member. The diffusion layer 32 only needs to be formed at least in the range where the emitted light from the micro-units of the planar light diffraction element 11a6 is incident. In the range where the emitted light from the micro-units is not incident, the diffusion layer 32 may not be formed, and instead, alignment marks for positioning may be provided. For example, in the optical arithmetic device 1B, alignment marks may be provided on the bottom surface of the leg portion 401. By providing alignment marks in the region where the diffusion layer 32 is not provided, it becomes easy to perform positioning while observing the alignment marks.

[0082] (Appendix matters)

[0083] The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. For embodiments obtained by appropriately combining the technical solutions separately disclosed in the above-described embodiments, they are also included in the technical scope of the present invention.

[0084] In addition, the "light diffraction element" in this specification is an element that converts an optical signal representing one piece of information (for example, one image) into an optical signal representing another piece of information (for example, another image). Therefore, its meaning is equivalent to that of a filter that converts an electrical signal representing one image into an electrical signal representing another image. The "light diffraction element" in this specification can be renamed as a "filter". In addition, the "optical arithmetic device" in this specification performs optical arithmetic using a light diffraction element, that is, using a filter. Therefore, the "optical arithmetic device" in this specification can be renamed as a "multi-layer filter device".

[0085] (Summary)

[0086] The optical computing device according to Embodiment 1 of the present invention includes: an optical diffraction element group including a plurality of planar optical diffraction elements made of a photocurable resin; and a cylindrical body that houses the optical diffraction element group, and at least a part of the outer edge of each planar optical diffraction element constituting the optical diffraction element group is fixed to the inner side surface of the cylindrical body.

[0087] According to the above structure, it is easy to maintain the relative positional relationship of the planar optical diffraction elements as a desired relationship.

[0088] Regarding the optical computing device according to Embodiment 2 of the present invention, on the basis of the structure of Embodiment 1, the following structure is adopted: in the space surrounded by the cylindrical body, a liquid or a solid for achieving refractive index matching is filled.

[0089] According to the above structure, it is possible to prevent foreign substances (including moisture) from easily entering the inside of the cylindrical body. Or, it is possible to suppress the vibration of the planar optical diffraction elements. Or, it is possible to suppress the aging (such as oxidation) of each planar optical diffraction element.

[0090] Regarding the optical computing device according to Embodiment 3 of the present invention, on the basis of the structure of Embodiment 1 or 2, the following structure is adopted: the refractive index of the liquid or the solid is greater than 1 and less than the refractive index of the planar optical diffraction elements.

[0091] According to the above structure, it is possible to reduce the reflection that may occur at the interface between the air and each planar optical diffraction element.

[0092] Regarding the optical computing device according to Embodiment 4 of the present invention, on the basis of any one of the structures of Embodiments 1 to 3, the following structure is adopted: the Young's modulus of elasticity of the cylindrical body is greater than the Young's modulus of elasticity of the optical diffraction element group.

[0093] According to the above structure, compared with the case where the optical diffraction element group is not housed in the cylindrical body and is exposed, it is possible to realize an optical computing device in which the relative positional relationship of the planar optical diffraction elements is not easily changed when an external force is applied.

[0094] Regarding the optical computing device according to Embodiment 5 of the present invention, on the basis of any one of the structures of Embodiments 1 to 4, the following structure is adopted: the thermal expansion rate of the cylindrical body is smaller than the thermal expansion rate of the planar optical diffraction elements.

[0095] According to the above structure, compared with the case where the optical diffraction element group is not housed in the cylindrical body and is exposed, it is possible to realize an optical computing device in which the relative positional relationship of the planar optical diffraction elements is not easily changed when the temperature changes.

[0096] Regarding the optical computing device according to Embodiment 6 of the present invention, on the basis of any one of the structures of Embodiments 1 to 5, the following structure is adopted: the cylindrical body transmits light for curing the photocurable resin.

[0097] According to the above structure, it is also possible to form a light diffraction element group inside the cylinder by irradiating light from the side. In addition, it is also easy to fix the outer edges of the respective planar light diffraction elements to the inner side surface of the cylinder by irradiating light from the side.

[0098] Regarding the optical arithmetic device of the seventh aspect of the present invention, on the basis of the structure of any one of the first to sixth aspects, the following structure is adopted: the shape of each planar light diffraction element constituting the light diffraction element group is a disc shape, and the shape of the cylinder is a cylindrical shape.

[0099] According to the above structure, even when thermal expansion of the light diffraction element group occurs, since stress acts uniformly on the entire outer edge of each planar light diffraction element, it is possible to reduce the possibility of occurrence of the following problems: unwanted deformation occurs in each planar light diffraction element; the relative positional relationship of the planar light diffraction elements changes.

[0100] Regarding the optical arithmetic device of the eighth aspect of the present invention, on the basis of the structure of any one of the first to seventh aspects, the following structure is adopted: two planar light diffraction elements that are included in the light diffraction element group and adjacent to each other are connected to each other by a columnar body made of the photocuring resin.

[0101] According to the above structure, it is easy to maintain the relative positional relationship of the arrangement directions of the planar light diffraction elements as a desired relationship, that is, it is easy to maintain the interval between adjacent planar light diffraction elements as a desired value.

[0102] Regarding the optical arithmetic device of the ninth aspect of the present invention, on the basis of the structure of any one of the first to eighth aspects, the following structure is adopted: at least one specific planar light diffraction element is included in the light diffraction element group, and the specific planar light diffraction element has a plurality of micro-units with individually set refractive indices.

[0103] According to the above structure, it is possible to realize an optical arithmetic device capable of performing multi-stage optical arithmetic.

[0104] Regarding the optical arithmetic device of the tenth aspect of the present invention, on the basis of the structure of any one of the first to ninth aspects, the following structure is adopted: a light conversion layer that converts infrared rays into visible light is provided at the subsequent stage of the planar light diffraction element at the last stage.

[0105] According to the above structure, it is possible to convert the infrared rays contained in the light emitted from the optical arithmetic device into visible light, and it is possible to detect the emitted light by a visible light imaging element.

[0106] Regarding the optical computing device of Embodiment 11 of the present invention, based on the structure of Embodiment 10, the following structure is adopted: A diffusion layer that diffuses the infrared rays or the visible light is further included at the subsequent stage of the planar optical diffraction element at the last stage.

[0107] According to the above structure, the light conversion efficiency of the light conversion layer can be improved.

[0108] Regarding the optical computing device of Embodiment 12 of the present invention, based on the structure of Embodiment 11, the following structure is adopted: A spacer is further included, and the spacer defines the distance from the planar optical diffraction element at the last stage to the diffusion layer.

[0109] According to the above structure, the distance from the planar optical diffraction element at the last stage to the diffusion layer can be defined with high dimensional accuracy.

[0110] The manufacturing method of the optical computing device of Embodiment 13 of the present invention is the manufacturing method of the optical computing device of any one of Embodiments 1 to 12, and the manufacturing method includes a shaping process of integrally shaping the optical diffraction element group inside the cylinder.

[0111] According to the above method, since the optical diffraction element group is integrally shaped inside the cylinder, it is easy to manufacture an optical computing device in which the relative positional relationship of the planar optical diffraction elements is the desired relationship.

[0112] Regarding the manufacturing method of the optical computing device of Embodiment 14 of the present invention, based on the manufacturing method of the optical computing device of Embodiment 13, the lower end of the cylinder is immersed in the uncured photocurable resin, or the uncured resin is injected into the inside of the cylinder with the lower end closed, and by pulling up the cured part of the optical diffraction element group upward while irradiating light from below, the optical diffraction element group is sequentially shaped inside the cylinder. In addition, two adjacent planar optical diffraction elements included in the optical diffraction element group are connected to each other by a columnar body made of the photocurable resin.

[0113] According to the above method, the optical diffraction element group is shaped using light (such as ultraviolet light), so compared with the case of shaping the optical diffraction element group using electron rays, the time required for shaping can be shortened. In addition, according to the above method, the optical diffraction element group can be shaped using a small amount of ultraviolet curable resin injected into a small pool or the inside of the cylinder, so the raw material cost can be suppressed.

[0114] Regarding the manufacturing method of the optical computing device of Embodiment 15 of the present invention, based on the manufacturing method of the optical computing device of Embodiment 13 or 14, after the shaping process, it further includes a fixing process. In this fixing process, by irradiating light from the side via the cylinder, at least a part of the outer edge of each planar optical diffraction element constituting the optical diffraction element group is fixed to the inner side surface of the cylinder. In addition, it is set that the cylinder transmits the light for curing the photocurable resin.

[0115] According to the above method, at least a part of the outer edge of each planar optical diffraction element constituting the optical diffraction element group can be more firmly fixed to the inner side surface of the cylinder.

[0116] Regarding the manufacturing method of the optical computing device of Embodiment 16 of the present invention, in the manufacturing method of the optical computing device of any one of Embodiments 13 to 15, after the shaping process, it further includes a discharging process. In this discharging process, by performing one or both of a developing process of injecting a developer into the inside of the cylinder and a cleaning process of injecting a cleaning liquid into the inside of the cylinder, the photocurable resin remaining between two adjacent planar optical diffraction elements included in the optical diffraction element group is discharged. In addition, it is set that through holes are provided in each planar optical diffraction element included in the optical diffraction element group.

[0117] According to the above method, the photocurable resin remaining between two adjacent planar optical diffraction elements can be discharged more reliably.

[0118] Explanation of reference numerals

[0119] 1 - Optical computing device; 11 - Optical diffraction element group; 11a1 to 11a6 - Planar optical diffraction elements; 11b1 to 11b5 - Columns (cylindrical); 11c1 to 11c5 - Columns (cylindrical); 12 - Cylinder; 13a, 13c - Bolts; 31 - Light conversion layer; 32 - Diffusion layer; 40 - Spacer; 401 - Leg; 402 - Plate part.

Claims

1. A light computing device, characterized in that, it comprises: a light diffraction element group, which includes a plurality of planar light diffraction elements made of a photocurable resin and a cylinder made of the photocurable resin, wherein the plurality of planar light diffraction elements are arranged with their central axes coinciding, and two adjacent planar light diffraction elements among them are interconnected by the cylinder; and a cylindrical body that houses the light diffraction element group, and at least a part of the outer edges of the respective planar light diffraction elements constituting the light diffraction element group are fixed to the inner side surface of the cylindrical body, the plurality of planar light diffraction elements and the cylinder are integrally formed.

2. The light computing device according to claim 1, characterized in that, a liquid or a solid is filled in the space surrounded by the cylindrical body.

3. The light computing device according to claim 2, characterized in that, the refractive index of the liquid or the solid is greater than 1 and less than the refractive index of the planar light diffraction element.

4. The light computing device according to any one of claims 1 to 3, characterized in that, the Young's modulus of elasticity of the cylindrical body is greater than that of the light diffraction element group.

5. The light computing device according to any one of claims 1 to 3, characterized in that, the thermal expansion rate of the cylindrical body is smaller than that of the planar light diffraction element.

6. The light computing device according to any one of claims 1 to 3, characterized in that, the cylindrical body transmits light for curing the photocurable resin.

7. The light computing device according to any one of claims 1 to 3, characterized in that, the shape of each planar light diffraction element constituting the light diffraction element group is a disc shape, the shape of the cylindrical body is a cylindrical shape.

8. The light computing device according to any one of claims 1 to 3, characterized in that, at least one specific planar light diffraction element is included in the light diffraction element group, and the specific planar light diffraction element has a plurality of micro-units with individually set refractive indices.

9. The light computing device according to any one of claims 1 to 3, characterized in that, a light conversion layer for converting infrared rays into visible light is provided at the subsequent stage of the last-stage planar light diffraction element.

10. The light computing device according to claim 9, characterized in that, a diffusion layer for diffusing the infrared rays or the visible light is further included at the subsequent stage of the last-stage planar light diffraction element.

11. The light computing device according to claim 10, characterized in that, a spacer is further included, and the spacer defines the distance from the last-stage planar light diffraction element to the diffusion layer.

12. A manufacturing method of a light computing device for manufacturing the light computing device according to any one of claims 1 to 11, characterized in that, the manufacturing method includes a shaping process of integrally shaping the light diffraction element group inside the cylindrical body, two adjacent planar light diffraction elements included in the light diffraction element group are interconnected by a cylinder made of the photocurable resin, In the shaping process, the lower end of the cylinder is immersed in the uncured photocurable resin, or the uncured resin is injected into the interior of the cylinder with a closed lower end, and by lifting the cured part of the light diffraction element group upward while irradiating light from below, the light diffraction element group is sequentially shaped inside the cylinder.

13. The method for manufacturing an optical arithmetic device according to claim 12, wherein, the cylinder transmits light for curing the photocurable resin, after the shaping process, a fixing process is further included, in which at least a part of the outer edge of each planar light diffraction element constituting the light diffraction element group is fixed to the inner side surface of the cylinder by irradiating light from the side via the cylinder.

14. The method for manufacturing an optical arithmetic device according to claim 12, wherein, through holes are provided in each planar light diffraction element included in the light diffraction element group, after the shaping process, a discharging process is further included, in which the photocurable resin remaining between two adjacent planar light diffraction elements included in the light diffraction element group is discharged by performing one or both of a developing process of injecting a developer into the interior of the cylinder and a cleaning process of injecting a cleaning liquid into the interior of the cylinder.

Images