Optical diffraction element unit, optical computing device, assembly method, and manufacturing method

Abstract

Provided is an optical diffraction element unit that is easy to handle. An optical diffraction element unit (U) is provided with: an optical diffraction element (1) that includes a substrate (10) having a first principal surface (principal surface 101) and a second principal surface (principal surface 102), an optical diffraction structure (11) comprising a plurality of microcells (A) being formed on the first principal surface (principal surface 101); and a first covering layer (covering layer 2) that covers the first principal surface (principal surface 101) and has a light transmission property.

Description

[Technical Field]

[0001] The present invention relates to an optical diffraction element unit including an optical diffraction structure consisting of a plurality of microcells, and an optical computing device including a plurality of such optical diffraction element units, as well as to methods for assembling and manufacturing such an optical computing device. [Background technology]

[0002] An optical diffraction element is known in which an optical diffraction structure is formed on one principal surface of a substrate. The optical diffraction structure has multiple microcells with individually set thicknesses or refractive indices, and optically performs a predetermined calculation by causing light transmitted through each microcell to interfere with each other. Here, "microcell" refers to a cell with a cell size of less than 10 μm, for example. Also, "cell size" refers to the square root of the cell area.

[0003] An optical arithmetic device using multiple optical diffraction elements has the advantage of being faster and consuming less power than an electrical arithmetic device using a processor. Patent Document 1 discloses an optical neural network having an input layer, a hidden layer, and an output layer. The above-mentioned optical diffraction element can be used, for example, as the hidden layer of such an optical neural network. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 7,847,225 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the optical diffraction structure constituting the optical diffraction element described above is a small structure, as can be seen from the cell size described above. Furthermore, in this optical diffraction structure, it is required that the material constituting it be translucent and that the thickness of each cell be individually designable. Therefore, the optical diffraction structure described above is often manufactured by stereolithography using a photocurable resin. As described above, small structures made of photocurable resin manufactured by stereolithography tend to lack mechanical strength.

[0006] Therefore, the optical diffraction elements described above require delicate handling and are difficult to handle. Furthermore, because it is difficult to handle each optical diffraction element, it is not practical for a user to change the combination of optical diffraction elements in an optical computing device that uses multiple optical diffraction elements.

[0007] One aspect of the present invention has been made in view of the above-mentioned problems, and its object is to provide an optical diffraction element unit that is easy to handle, and an optical computing device that includes a plurality of such optical diffraction element units. Another object of one aspect of the present invention is to provide an assembly method and a manufacturing method for an optical computing device that uses an optical diffraction element unit that is easy to handle. [Means for solving the problem]

[0008] In order to solve the above problem, an optical diffraction element unit according to one embodiment of the present invention includes a substrate having a first main surface and a second main surface, an optical diffraction element having an optical diffraction structure consisting of a plurality of microcells formed on the first main surface, and a first coating layer covering the first main surface and having optical transparency. [Effects of the Invention]

[0009] According to one aspect of the present invention, it is possible to provide an optical diffraction element unit that is easy to handle, and an optical computing device that includes a plurality of such optical diffraction element units. Also, according to another aspect of the present invention, it is possible to provide an assembly method and a manufacturing method for an optical computing device that uses an optical diffraction element unit that is easy to handle. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view of an optical diffraction element unit according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the optical diffraction element unit shown in FIG. [Figure 3] FIG. 2 is a cross-sectional view of a first modified example of the optical diffraction element unit shown in FIG. [Figure 4] FIG. 2 is a cross-sectional view of a second modified example of the optical diffraction element unit shown in FIG. [Figure 5] FIG. 10 is an exploded cross-sectional view of an optical arithmetic device according to a second embodiment of the present invention. [Figure 6] FIG. 6 is an exploded cross-sectional view of a modified example of the optical arithmetic device shown in FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] <Configuration of the optical diffraction element unit> An optical diffraction element unit U according to a first embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a perspective view of the optical diffraction element unit U. Fig. 2 is a cross-sectional view of the optical diffraction element unit U. Note that hatching has been omitted in Fig. 2 to make the drawing easier to see.

[0012] As shown in Fig. 1, the optical diffraction element unit U includes an optical diffraction element 1 and a covering layer 2. In Fig. 2, the covering layer 2 is shown by a virtual line (two-dot chain line).

[0013] (optical diffraction element) The optical diffraction element 1 is a plate-like element having optical transparency. As shown in FIG.

[0014] The substrate 10 is a substrate having a principal surface 101 and a principal surface 102 facing each other, and is a light-transmitting substrate. The principal surface 101 and the principal surface 102 are examples of the first and second principal surfaces of an optical diffraction element, respectively, and are smooth flat surfaces. In this embodiment, the principal surface 102 is exposed.

[0015] The thickness of the substrate 10 is determined so that the sum of the thickness of the substrate 10 and the thickness of the coating layer 2 described below will be a desired thickness. In this embodiment, the thickness of the substrate 10 is 30 μm, but is not limited to this.

[0016] In this embodiment, the substrate 10 is made of glass (for example, quartz glass), but may also be made of resin (for example, photocurable resin).

[0017] The light diffraction structure 11 is formed on the main surface 101. The light diffraction structure 11 is composed of a plurality of microcells A, each having a thickness or refractive index set independently of one another. In this embodiment, each microcell A is made of a light-transmitting resin (e.g., a photocurable resin). However, the light diffraction structure 11 may also be made of glass (e.g., quartz glass).

[0018] When signal light is incident on the optical diffraction structure 11, a predetermined optical operation is performed by the signal light that has passed through each microcell A interfering with each other. The intensity distribution of the signal light output from the optical diffraction structure 11 represents the result of the optical operation.

[0019] Here, "microcell" refers to a cell with a cell size of less than 10 μm, for example. Also, "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.

[0020] 1 is composed of 1000 x 1000 microcells A arranged in a matrix. The planar shape of each microcell A is, for example, a 1 μm x 1 μm square, and the planar shape of the optical diffraction structure 11 is, for example, a 1 mm x 1 mm square.

[0021] The cell size, the planar shape of each microcell A, and the planar shape of the light diffraction structure 11 are not limited to the above examples, and can be determined as appropriate.

[0022] (covering layer) 1, coating layer 2 is a layer- or plate-like member having opposing principal surfaces 21 and 22, and is a light-transmitting member. Principal surface 21 is an example of one of the pair of principal surfaces of the first coating layer, which is provided on the side opposite to the substrate, and is a smooth plane similar to principal surfaces 101 and 102.

[0023] The thickness of the coating layer 2 is determined so that the sum of the thicknesses of the coating layer 2 and the substrate 10 described above is a desired thickness. In this embodiment, the thickness of the coating layer 2 is 10 μm, but is not limited to this. By setting the thickness of the substrate 10 to 30 μm and the thickness of the coating layer 2 to 10 μm, when multiple optical diffraction element units U are stacked (for example, when stacked as shown in FIG. 5 described below), the spacing between the optical diffraction structures 11 between adjacent optical diffraction element units U can be made to approximately match the sum of the thickness of the substrate 10 and the thickness of the coating layer 2. Therefore, the spacing between the optical diffraction structures 11 can be easily made to approximately match the desired value. Note that the thicknesses of the substrate 10 and the coating layer 2 described above are determined assuming that the wavelength λ of the signal light is λ=1.5 μm and the refractive index of the materials constituting the substrate 10 and the coating layer 2 is 1.5.

[0024] The covering layer 2 is formed on the main surface 101 so that the main surface 22 is in direct contact with the main surface 101 of the substrate 10 and the surface of the optical diffraction structure 11. The covering layer 2 covers the main surface 101 and the surface of the optical diffraction structure 11. In this embodiment, the optical diffraction structure 11 is embedded in the covering layer 2.

[0025] In this embodiment, the covering layer 2 is made of a light-transmitting resin (for example, a photocurable resin), but may also be made of glass (for example, quartz glass).

[0026] In this embodiment, the main surface 21 is configured to be parallel or approximately parallel to each of the main surface 101 and the main surface 102.

[0027] Both the main surface 21 and the main surface 102 are smooth flat surfaces. 。

[0028] < First Modification> An optical diffraction element unit UA, which is a first modified example of the optical diffraction element unit U, will be described with reference to Fig. 3. Fig. 3 is a cross-sectional view of the optical diffraction element unit UA. In Fig. 3, hatching has been omitted except for the matching oil 24A to make the drawing easier to see.

[0029] As shown in FIG. 3, the optical diffraction element unit UA is obtained by replacing the covering layer 2 of the optical diffraction element unit U shown in FIG. 2 with a covering layer 2A.

[0030] Like the coating layer 2, the coating layer 2A is a layered or plate-like member having opposing principal surfaces 21A and 22A, and is a light-transmitting member. However, unlike the coating layer 2, a recess 23A is formed in the principal surface 22A, which is the principal surface of the pair of principal surfaces that is provided on the substrate 10 side. The recess 23A is formed so as to encompass the optical diffraction structure 11 when the coating layer 2A is viewed in plan. Furthermore, the depth of the recess 23A exceeds the maximum thickness of the optical diffraction structure 11. Therefore, when the coating layer 2A is laminated on the principal surface 101, the coating layer 2A is separated from the optical diffraction structure 11, and the optical diffraction structure 11 is accommodated in the space formed by the substrate 10 and the coating layer 2A.

[0031] In this embodiment, the space between the substrate 10 and the coating layer 2A is filled with a light-transmitting oil 24. The oil 24 functions as a matching oil that matches the refractive index of the optical diffraction structure 11 with the refractive index of the coating layer 2A. Therefore, the refractive index of the oil 24 is appropriately determined depending on the refractive index of the optical diffraction structure 11 and the refractive index of the coating layer 2A.

[0032] The substance filled in the space described above is not limited to oil, such as oil 24, and may be any substance that is translucent. This substance may be, for example, a liquid, a gas, or a resin. Whether the substance is a liquid, a gas, or a resin, it is preferable that it does not contain oxygen molecules or moisture. Furthermore, when the substance is a gas, the gas may be composed of a single type of molecule or multiple types of molecules.

[0033] <Second Modification> An optical diffraction element unit UB, which is a second modified example of the optical diffraction element unit U, will be described with reference to Fig. 4. Fig. 4 is a cross-sectional view of the optical diffraction element unit UB. Note that hatching has been omitted in Fig. 4 to make the drawing easier to see.

[0034] As shown in Fig. 4, the optical diffraction element unit UB is obtained by changing the inclination of the principal surface 102B relative to the principal surface 101B and the inclination of the principal surface 21B relative to the principal surface 101B, based on the optical diffraction element unit U shown in Fig. 2. Specifically, in the optical diffraction element unit U, the principal surface 101 and the principal surface 102 are parallel, and the principal surface 101 and the principal surface 21 are parallel. That is, the principal surface 101, the principal surface 102, and the principal surface 21 are all parallel. On the other hand, in the optical diffraction element unit UB, the principal surface 102B and the principal surface 21B are parallel, but the principal surface 101B and the principal surface 102B are non-parallel, and the principal surface 101B and the principal surface 21B are non-parallel.

[0035] Because the main surface 102B and the main surface 21B are parallel, even when a plurality of optical diffraction element units UB are stacked (for example, when stacked as shown in FIG. 5 described later), the main surfaces 101B of adjacent optical diffraction element units UB are parallel. Therefore, the optical diffraction structures 11 of adjacent optical diffraction element units UB can be correctly positioned. Furthermore, the interval between the optical diffraction structures 11 of adjacent optical diffraction element units UB can be easily made to approximately match a desired value.

[0036] Second Embodiment <Configuration of optical computing device> An optical arithmetic device AC according to a second embodiment of the present invention will be described with reference to Fig. 5. Fig. 5 is an exploded cross-sectional view of the optical arithmetic device AC. Note that hatching has been omitted in Fig. 5 to make the drawing easier to see.

[0037] As shown in FIG. 5, the optical computing device AC includes three optical diffraction element units UC, a cover CU, and a cover CB.

[0038] (Optical diffraction element unit) The optical diffraction element unit UC is a third modified example of the optical diffraction element unit U shown in Fig. 2. The optical diffraction structure 11 included in the optical diffraction element unit UC is configured identically to the optical diffraction structure 11 included in the optical diffraction element unit U. The substrate 10C and covering layer 2C included in the optical diffraction element unit UC are obtained by changing the shape of the main surface 102 of the substrate 10 and the shape of the main surface 21 of the covering layer 2 included in the optical diffraction element unit U, respectively. Like the optical diffraction element unit U, the main surface 102C of the optical diffraction element unit UC, which is a single unit, is exposed.

[0039] A plurality of convex portions (five in FIG. 5) each having a rectangular cross section are formed on the main surface 102C. Each convex portion may be a strip-shaped convex portion extending along the depth direction of FIG. 5. Each convex portion may be composed of a plurality of sub-convex portions spaced apart from each other when viewed along the depth direction of FIG. 5.

[0040] The main surface 21C is formed with a plurality of recesses (five in FIG. 5) each having a rectangular cross section, in a shape complementary to the shape of the main surface 102C.

[0041] In this way, the shape of the convex portions formed on the main surface 102C and the shape of the concave portions formed on the main surface 21C are mutually mutually opposite. Supplementary With this configuration, when a plurality of optical diffraction element units UC are stacked as shown in Fig. 5, the principal surfaces 102C and 21C of adjacent optical diffraction element units UC come into contact with each other without or with almost no gaps at the interface.

[0042] (cover) The covers CU and CB are configured to cover the pair of main surfaces of the optical computing unit AC, respectively. In the state shown in FIG. 5, the cover CU functions as an upper cover, and the cover CB functions as a lower cover.

[0043] Of the main surfaces of the cover CU, the main surface on the optical diffraction element unit UC side (the lower main surface in FIG. 5) has a plurality of convex portions (five in FIG. 5) with a rectangular cross section formed in a shape complementary to the shape of the main surface 21C. The multiple convex portions formed on the cover CU have the same shape as the multiple convex portions formed on the main surface 102C. The main surface of the cover CU opposite the optical diffraction element unit UC is made of a smooth flat surface.

[0044] A plurality of recesses (five in FIG. 5) having a rectangular cross section are formed in the main surface of the cover CB on the side of the optical diffraction element unit UC (the upper main surface in FIG. 5). The recesses formed in the cover CB have the same shape as the recesses formed in the main surface 21C. The main surface of the cover CB opposite the optical diffraction element unit UC is made of a smooth flat surface.

[0045] Since the optical computing unit AC is provided with the covers CU and CB, the pair of main surfaces that function as the entrance surface and exit surface of the optical computing unit AC are both smooth flat surfaces.

[0046] (Fixing optical diffraction element units UC together) In the optical diffraction element units UC, adjacent optical diffraction element units UC may or may not be fixed to each other using an adhesive layer described below. When adjacent optical diffraction element units UC are fixed to each other, it is possible to prevent the positions of the optical diffraction structures 11 from shifting. On the other hand, when adjacent optical diffraction element units UC are not fixed to each other, it is possible to arbitrarily change the combination of the multiple optical diffraction element units UC that make up the optical computing device AC.

[0047] The optical diffraction element unit UC is configured so that the sum of the thickness of the substrate 10C and the thickness of the coating layer 2C is the desired value, so that the spacing between the optical diffraction structures 11 in adjacent optical diffraction element units UC can easily be made to approximately match the desired value.

[0048] Furthermore, when adjacent optical diffraction element units UC are not fixed to each other using an adhesive, each optical diffraction element unit UC may be fixed using a selective fixing means that can arbitrarily select between a fixed state and an unfixed state. The selective fixing means may be a guide with a groove cut therein having the same width as each optical diffraction element unit UC, or may be a case that can accommodate multiple optical diffraction element units UC in a stacked state.

[0049] The guide or case may be provided with a stopper using a leaf spring. For example, when the selective fixing means is a stopper, a leaf spring may be interposed between the cover CU of the optical computing unit AC and the top cover of the case. ContainmentBy closing the top cover of the case in this state, a force that sandwiches the optical processing device AC acts on the stacked optical diffraction element units UC along the normal direction of the main surface 101C. This force is generated by the leaf springs. This allows the positions of the optical diffraction element units UC and covers CU and CB to be maintained in the optical processing device AC. Furthermore, with this configuration, opening the top cover of the case eliminates the force that sandwiches the optical processing device AC, making it possible to change the combination of optical diffraction element units UC.

[0050] Alternatively, only one cover (for example, cover CB) may be fixed to the case with an adhesive, and a plurality of optical diffraction element units UC may be stacked on top of that cover.

[0051] Furthermore, when the main surfaces 21C, 102C of each optical diffraction element unit UC are configured as smooth flat surfaces (see, for example, FIGS. 2 to 4), the covers CU, CB may be fixed to the case using adhesive. The distance between the covers CU and CB may be determined appropriately depending on the number of optical diffraction element units UC to be stacked. This configuration allows the combination of optical diffraction element units UC to be changed.

[0052] <Assembly and manufacturing methods> One aspect of the present invention also includes an assembly method and a manufacturing method for an optical computing device AC including a plurality of optical diffraction element units UC. The assembly method is a method in which each optical diffraction element unit UC is shipped from a factory in an independent state, and a user obtains the optical computing device AC by assembling each optical diffraction element unit UC. The manufacturing method is a method in which the optical computing device AC is manufactured in a factory.

[0053] By implementing this assembly method, the user can select optical diffraction element units UC capable of performing the desired optical calculation, and by combining multiple selected optical diffraction element units UC, an optical calculation device AC can be assembled.

[0054] Of the three optical diffraction element units UC shown in Fig. 5, two adjacent optical diffraction element units UC are an example of a first optical diffraction element unit and a second optical diffraction element unit. In this embodiment, the lower, middle, and upper optical diffraction element units UC shown in Fig. 5 are the first optical diffraction element unit, the second optical diffraction element unit, and the third optical diffraction element unit, respectively. Note that the number of optical diffraction element units UC constituting the optical computing device AC is not limited to three, and may be any plural number.

[0055] The present assembly method and manufacturing method include a step of bringing the main surface 21C of the optical diffraction element unit UC shown in the lower part of FIG. 5 and the main surface 102C of the optical diffraction element unit UC shown in the middle part of FIG. 5 into contact with each other.

[0056] In this step, the principal surfaces 21C and 102C may be fixed together using a light-transmitting adhesive layer. That is, the principal surfaces 21C and 102C may be in contact with each other via the adhesive layer. The adhesive layer may be made of a light-transmitting resin (e.g., a photocurable resin).

[0057] Furthermore, this assembly method and this manufacturing method further include the steps of bringing the main surface of the cover CB on the optical diffraction element unit UC side into contact with the main surface 102C of the optical diffraction element unit UC shown in the lower part of Fig. 5, bringing the main surface 21C of the optical diffraction element unit UC shown in the middle part of Fig. 5 into contact with the main surface 102C of the optical diffraction element unit UC shown in the upper part of Fig. 5, and bringing the main surface 21C of the optical diffraction element unit UC shown in the upper part of Fig. 5 into contact with the main surface of the cover CU on the optical diffraction element unit UC side. The dashed-dotted arrows in Fig. 5 indicate these steps.

[0058] In this embodiment, the optical computing device AC is configured using a plurality of optical diffraction element units UC. However, the optical diffraction element units that configure the optical computing device AC according to one embodiment of the present invention are not limited to the optical diffraction element units UC, and may be any optical diffraction element units according to one embodiment of the present invention (see, for example, FIGS. 1 to 4).

[0059] <Modification> An optical arithmetic device AD, which is a modified example of the optical arithmetic device AC, will be described with reference to Fig. 6. Fig. 6 is an exploded cross-sectional view of the optical arithmetic device AD. Note that hatching has been omitted in Fig. 6 to make the drawing easier to see.

[0060] The optical calculation device AD is obtained by replacing each optical diffraction element unit UC with an optical diffraction element unit UD based on the optical calculation device AC. The optical diffraction element unit UD is a fourth modified example of the optical diffraction element unit U shown in FIG.

[0061] The optical diffraction element unit UD includes a covering layer 3D in addition to the optical diffraction element 1D and the covering layer 2D. The optical diffraction element 1D and the covering layer 2D correspond to the optical diffraction element 1 and the covering layer 2, respectively, of the optical diffraction element unit U. The covering layer 3D is an example of a second covering layer.

[0062] Covering layer 3D is a layer- or plate-like member having opposing principal surfaces 31D and 32D, and is a light-transmitting member. Principal surface 32D is an example of the pair of principal surfaces of the second covering layer that is provided on the side opposite to the substrate.

[0063] The thickness of the covering layer 3D is determined so that the sum of the thickness of the substrate 10D, the thickness of the covering layer 2D, and the thickness of the covering layer 3D becomes a desired thickness.

[0064] A plurality of convex portions (five in FIG. 6) each having a rectangular cross section are formed on the principal surface 32D. These convex portions are configured in the same manner as the convex portions formed on the principal surface 102C in the optical diffraction element unit UC shown in FIG.

[0065] The main surface 21D has a plurality of recesses (see FIG. 1) each having a rectangular cross section that is complementary to the shape of the main surface 32D. 6 These recesses are formed in the same manner as the recesses formed on the main surface 21C in the optical diffraction element unit UC shown in FIG.

[0066] In this way, the shape of the convex portions formed on the main surface 32D and the shape of the concave portions formed on the main surface 21D are mutually mutually opposite. Supplementary With this configuration, when a plurality of optical diffraction element units UC are stacked as shown in Fig. 6, the principal surfaces 32D and 21D of adjacent optical diffraction element units UD come into contact with each other without or with almost no gaps at the interface.

[0067] The present assembly method and manufacturing method can be applied to the same assembly method and manufacturing method as the optical computing device AC.

[0068] The assembling method and manufacturing method of the optical computing device AD includes a step of bringing the main surface 21D of the optical diffraction element unit UD shown in the lower part of Fig. 6 into contact with the main surface 32D of the optical diffraction element unit UD shown in the middle part of Fig. 6. This step may be configured to fix the main surface 21D and the main surface 32D using a light-transmitting adhesive layer.

[0069] Moreover, this assembly method and this manufacturing method further include the steps of bringing the main surface of the cover CB on the optical diffraction element unit UD side into contact with the main surface 32D of the optical diffraction element unit UD shown in the lower part of Fig. 6, bringing the main surface 21D of the optical diffraction element unit UD shown in the middle part of Fig. 6 into contact with the main surface 32D of the optical diffraction element unit UD shown in the upper part of Fig. 6, and bringing the main surface 21D of the optical diffraction element unit UD shown in the upper part of Fig. 6 into contact with the main surface of the cover CU on the optical diffraction element unit UD side. The dashed-dotted arrows in Fig. 6 indicate these steps. (summary)

[0070] The optical diffraction element unit according to a first aspect of the present invention includes a substrate having a first main surface and a second main surface, an optical diffraction element having an optical diffraction structure consisting of a plurality of microcells formed on the first main surface, and a first coating layer covering the first main surface and having optical transparency.

[0071] According to the above configuration, the optical diffraction structure is covered with the first covering layer together with the first principal surface, and therefore the optical diffraction structure can be protected from external pressure, impact, etc. Therefore, the optical diffraction element unit can be made easier to handle.

[0072] In addition, in the optical diffraction element unit according to the second aspect of the present invention, in addition to the configuration of the optical diffraction element unit according to the first aspect described above, a configuration is adopted in which the optical diffraction structure is embedded in the first coating layer.

[0073] According to the above configuration, the first coating layer blocks contact between the optical diffraction structure and air, thereby preventing foreign matter such as dust from adhering to the optical diffraction structure. Furthermore, the first coating layer blocks contact between the optical diffraction structure and oxygen molecules and moisture contained in the air, thereby preventing deterioration of the optical diffraction structure.

[0074] In addition, in the optical diffraction element unit according to the third aspect of the present invention, in addition to the configuration of the optical diffraction element unit according to the first aspect described above, a configuration is adopted in which the first coating layer is spaced apart from the optical diffraction structure.

[0075] According to the above configuration, the present optical diffraction element unit can be manufactured simply by covering it with a coating that has been prepared in advance in a separate process, making it easier to manufacture than the optical diffraction element unit according to the second aspect described above.

[0076] In addition, in the optical diffraction element unit according to the fourth aspect of the present invention, in addition to the configuration of the optical diffraction element unit according to the third aspect described above, a configuration is adopted in which the space between the first coating layer and the optical diffraction structure is filled with any of a liquid, a gas, and a resin.

[0077] According to the above configuration, the space around the optical diffraction structure is filled with either a liquid, a gas, or a resin, thereby blocking contact between the optical diffraction structure and the air present outside the optical diffraction element unit. Therefore, adhesion of foreign matter such as dust to the optical diffraction structure can be suppressed. Furthermore, if the liquid, gas, or resin filling the space does not contain oxygen molecules or moisture, the optical diffraction structure is blocked from contact with the oxygen molecules and moisture contained in the air, so the optical diffraction element unit can suppress deterioration of the optical diffraction structure.

[0078] Furthermore, in the optical diffraction element unit according to the fifth aspect of the present invention, in addition to the configuration of the optical diffraction element unit according to any one of the first to fourth aspects described above, a second coating layer that covers the second main surface and has light-transmitting properties is further provided, and a configuration is adopted in which the shape of the main surface of the pair of main surfaces of the first coating layer that is provided on the opposite side of the substrate and the shape of the main surface of the pair of main surfaces of the second coating layer that is provided on the opposite side of the substrate are complementary to each other.

[0079] Furthermore, in the optical diffraction element unit according to the sixth aspect of the present invention, in addition to the configuration of the optical diffraction element unit according to any one of the first to fourth aspects described above, a configuration is adopted in which the second main surface is exposed, and the shape of the main surface of the pair of main surfaces of the first coating layer that is provided on the side opposite the substrate and the shape of the second main surface are complementary to each other.

[0080] According to the optical diffraction element unit of the fifth aspect of the present invention, when an optical computing device is configured using at least two optical diffraction element units, one of the pair of main surfaces of the first coating layer, which is provided on the side opposite the substrate, can be in contact with one of the pair of main surfaces of the second coating layer, which is provided on the side opposite the substrate, without any gaps. Furthermore, according to the optical diffraction element unit of the sixth aspect of the present invention, when an optical computing device is configured using at least two optical diffraction element units, the one of the pair of main surfaces of the first coating layer, which is provided on the side opposite the substrate, can be in contact with the second main surface, without any gaps. Therefore, reflection loss that may occur at the interface between these main surfaces can be suppressed.

[0081] An optical computing device according to a seventh aspect of the present invention includes at least a first optical diffraction element unit and a second optical diffraction element unit, which are optical diffraction element units according to any one of the first to sixth aspects described above, and the pair of main surfaces of the first coating layer of the first optical diffraction element unit, one of which is provided on the side opposite the substrate, is in contact with the second main surface of the second optical diffraction element unit, or the pair of main surfaces of the second coating layer covering the second main surface, one of which is provided on the side opposite the substrate.

[0082] An optical computing device according to a seventh aspect of the present invention includes an optical diffraction element unit according to one aspect of the present invention. Therefore, in this optical computing device, the optical diffraction element unit can be easily handled. Therefore, this optical computing device can be easily assembled and manufactured. Furthermore, according to the above configuration, by setting the thickness of the optical diffraction element unit (the sum of the thickness of the substrate and the thickness of the first coating layer, or the sum of the thickness of the substrate, the thickness of the first coating layer, and the thickness of the second coating layer) to a desired value, when an optical computing device is constructed by stacking multiple optical diffraction element units, the spacing between the optical diffraction structures can be made to approximately match a desired value. Therefore, this optical computing device is suitable for constructing an optical computing device in which the combination of multiple optical diffraction element units can be easily changed.

[0083] An assembly method according to an eighth aspect of the present invention is a method for assembling an optical computing device including at least a first optical diffraction element unit and a second optical diffraction element unit, which are optical diffraction element units according to any one of the first to sixth aspects described above, and includes a step of contacting one of a pair of main surfaces of the first coating layer of the first optical diffraction element unit, which is provided on the side opposite the substrate, with a second main surface of the second optical diffraction element unit, or one of a pair of main surfaces of a second coating layer covering the second main surface, which is provided on the side opposite the substrate.

[0084] A manufacturing method according to a ninth aspect of the present invention is a method for manufacturing an optical computing device including at least a first optical diffraction element unit and a second optical diffraction element unit, which are optical diffraction element units according to any one of the first to sixth aspects described above, and includes a step of contacting one of a pair of main surfaces of the first coating layer of the first optical diffraction element unit, which is provided on the side opposite the substrate, with a second main surface of the second optical diffraction element unit, or one of a pair of main surfaces of a second coating layer covering the second main surface, which is provided on the side opposite the substrate.

[0085] The assembly method according to the eighth aspect of the present invention and the manufacturing method according to the ninth aspect of the present invention include the optical diffraction element unit according to one aspect of the present invention. Therefore, when assembling or manufacturing the optical diffraction element unit, the assembly method and the manufacturing method allow the optical diffraction element unit to be easily handled. Therefore, the assembly method and the manufacturing method allow the optical calculation device to be easily assembled or manufactured.

[0086] [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 different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0087] AC,AD optical calculation device U, UA, UB, UC, UD Optical Diffraction Element Unit 1,1A,1B,1C,1D Optical diffraction element 10, 10B, 10C, 10D board 101,102,101B,102B,101C,102C,101D,102D Main surface 11 Optical diffractive structure 2,2A,2B,2C,2D Covering layer 21,22,21A,22A,21B,22B,21C,22C,21D,22D Main surface

Claims

1. an optical diffraction element including a substrate having a first main surface and a second main surface, wherein an optical diffraction structure consisting of a plurality of microcells is formed on the first main surface; a first coating layer covering the first main surface and having light-transmitting properties; a second coating layer covering the second main surface and having light-transmitting properties; a third main surface of the pair of main surfaces of the first coating layer, which is provided on the side opposite to the substrate, and a fourth main surface of the pair of main surfaces of the second coating layer, which is provided on the side opposite to the substrate, have a shape complementary to each other, or are both flat; a surface shape of the optical diffraction structure is different from each of the third principal surface and the fourth principal surface, The plurality of microcells are composed of a plurality of microcells whose thicknesses or refractive indices are set independently of each other. An optical diffraction element unit characterized by:

2. the optical diffraction structure is embedded in the first coating layer; 2. The optical diffraction element unit according to claim 1.

3. the first coating layer is spaced apart from the light-diffractive structure; 2. The optical diffraction element unit according to claim 1.

4. a space between the first coating layer and the optical diffraction structure is filled with any one of a liquid, a gas, and a resin; 4. The optical diffraction element unit according to claim 3.

5. a plurality of recesses are formed in one of the pair of main surfaces of the first coating layer, the main surface being provided on the opposite side to the substrate; a plurality of convex portions are formed on one of the pair of main surfaces of the second coating layer, the main surface being provided on the side opposite to the substrate; 5. The optical diffraction element unit according to claim 1, wherein the optical diffraction element unit is a diffraction element.

6. an optical diffraction element including a substrate having a first main surface and a second main surface, wherein an optical diffraction structure consisting of a plurality of microcells is formed on the first main surface; a first coating layer that covers the first main surface and has light-transmitting properties; the second main surface is exposed; a third main surface of the pair of main surfaces of the first coating layer, the third main surface being provided on the side opposite to the substrate, and a shape of the second main surface are complementary to each other, or both are flat surfaces; a surface shape of the optical diffraction structure is different from each of the third principal surface and the second principal surface, The plurality of microcells are composed of a plurality of microcells whose thicknesses or refractive indices are set independently of each other. An optical diffraction element unit characterized by:

7. a plurality of recesses are formed in one of the pair of main surfaces of the first coating layer, the main surface being provided on the opposite side to the substrate; A plurality of protrusions are formed on the second main surface.

7. The optical diffraction element unit according to claim 6.

8. The optical diffraction element unit according to any one of claims 1 to 7, including at least a first optical diffraction element unit and a second optical diffraction element unit, a main surface of the pair of main surfaces of the first coating layer of the first optical diffraction element unit that is provided on the opposite side to the substrate and a second main surface of the second optical diffraction element unit, or a main surface of the pair of main surfaces of the second coating layer that covers the second main surface that is provided on the opposite side to the substrate, are in contact with each other; An optical computing device characterized by:

9. A method for assembling an optical arithmetic device including at least a first optical diffraction element unit and a second optical diffraction element unit, each of which is the optical diffraction element unit according to any one of claims 1 to 7, comprising: a step of bringing into contact with one of a pair of main surfaces of the first coating layer of the first optical diffraction element unit, the main surface being provided on the opposite side to the substrate, and a second main surface of the second optical diffraction element unit, or a main surface of a pair of main surfaces of a second coating layer covering the second main surface, the main surface being provided on the opposite side to the substrate, An assembly method characterized by:

10. A method for manufacturing an optical arithmetic device including at least a first optical diffraction element unit and a second optical diffraction element unit, which are the optical diffraction element units according to any one of claims 1 to 7, comprising: a step of bringing into contact with one of a pair of main surfaces of the first coating layer of the first optical diffraction element unit, the main surface being provided on the opposite side to the substrate, and a second main surface of the second optical diffraction element unit, or a main surface of a pair of main surfaces of a second coating layer covering the second main surface, the main surface being provided on the opposite side to the substrate, A manufacturing method characterized by:

Images