Optical diffraction element unit and optical computing device

Abstract

Provided is an optical diffraction element unit that easily maintains the shape of a main surface of a substrate as a plane even as a single body, the optical diffraction element unit (U) including: a layered substrate (11); an optical diffraction structure (12) formed on a portion (central portion 113) of a main surface (111) of the substrate (11); and a holding portion (20) that is provided with an opening (23) and holds a ring-shaped portion (114) surrounding the portion (central portion 113) in the substrate (11) in such a manner that the optical diffraction structure (12) is included in the opening (23).

Description

Technical Field

[0001] The present invention relates to an optical diffraction element unit comprising an optical diffraction structure composed of multiple micro-units, and an optical computing device having multiple such optical diffraction element units. Background Technology

[0002] A known optical diffraction element comprises: a substrate composed of a translucent layered component, and an optical diffraction structure formed on a main surface of the substrate. The optical diffraction structure has multiple micro-units with independently set thicknesses or refractive indices, such that signal light passing through each micro-unit interferes with each other, thereby performing a predetermined operation optically. Here, "micro-unit" refers to a unit with a unit size less than 10 μm. Furthermore, "unit size" refers to the square root of the unit's area.

[0003] By using multiple such optical diffraction elements and periodically arranging each optical diffraction structure along the direction of signal light propagation (i.e., the thickness direction of the microcell), an optical computing device that performs multiple optical operations, i.e., optical calculations, is obtained. Such an optical computing device has the advantages of being faster and less power-consuming than an electrical computing device using a processor. Patent Document 1 discloses an optical neural network having an input layer, an intermediate layer, and an output layer. The aforementioned optical diffraction elements can, for example, be used as the intermediate layer of such an optical neural network. Existing technical documents Patent documents

[0004] Patent Document 1: US Patent No. 7,847,225 Summary of the Invention (a) Technical problems to be solved

[0005] In such optical processing devices, the spacing D between periodically arranged optical diffraction structures is roughly determined corresponding to the wavelength λ of the signal light. As an example of this spacing D, D = 40λ. That is, when light with λ = 1.5 μm is used as the signal light, D = 60 μm. In this case, it is required that the sum of the maximum thickness of the substrate and the thickness of the micro-unit be less than 60 μm. Therefore, it is common to use a thin resin film as the substrate for the optical diffraction element. Examples of resin film thicknesses include 3 μm and 5 μm. However, such resin films are flexible, making it difficult to accurately maintain the planar shape of the main surface.

[0006] The present invention addresses the above-mentioned problems by providing a light diffraction element unit that, even as a single unit, easily maintains the main surface shape of the substrate as planar, and an optical computing device having multiple such light diffraction element units. (II) Technical Solution

[0007] To address the aforementioned problems, one aspect of the present invention provides a light diffraction element unit comprising: a substrate, which is a layered component having light transmittance and flexibility; a light diffraction structure formed on a portion of a main surface of the substrate, comprising a plurality of micro-units; and a holding portion, which is a layered or plate-like component having an opening penetrating a pair of main surfaces, for holding the substrate. In this light diffraction element unit, the holding portion employs a structure in which the annular portion surrounding the main surface of the substrate is held by the holding portion such that the opening includes the light diffraction structure.

[0008] To solve the above problems, an optical computing device according to one aspect of the present invention includes: a first optical diffraction element unit to an Nth optical diffraction element unit (N is an integer greater than or equal to 2), which are the optical diffraction element units of the present invention described above; and a housing that sequentially houses each of the first optical diffraction element units to the Nth optical diffraction element units along the normal direction of one main surface of the substrate. (III) Beneficial Effects

[0009] According to one aspect of the present invention, it is possible to provide a light diffraction element unit that, even as a single unit, easily maintains the main surface shape of the substrate as planar, and an optical computing device having a plurality of such light diffraction element units. Attached Figure Description

[0010] Figure 1 This is an exploded perspective view of the optical diffraction element unit according to the first embodiment of the present invention. Figure 2 yes Figure 1 The cross-sectional view of the optical diffraction element unit shown. Figure 3 yes Figure 1 A three-dimensional view of the optical diffraction element unit shown. Figure 4 yes Figure 1 A cross-sectional view of a first modified example of the optical diffraction element unit shown. Figure 5 yes Figure 1 A cross-sectional view of a second modified example of the optical diffraction element unit shown. Figure 6 This is a cross-sectional view of the optical computing device according to the second embodiment of the present invention. Detailed Implementation

[0011] (First Implementation) (Structure of an optical diffraction element unit) Reference Figures 1-3 The optical diffraction element unit U of the first embodiment of the present invention will be described. Figure 1 This is an exploded stereoscopic view of the optical diffraction element unit U. Figure 2This is a cross-sectional view of the optical diffraction element unit U, along... Figure 1 The A-A' section shown is a cross-sectional view of the A-A' line. The A-A' section is a section perpendicular to the opposing main surfaces 211 and 222 of the holding part 20, and is a section through the light diffraction structure 12. Figure 3 This is a perspective view of the optical diffraction element 10 included in the optical diffraction element unit U. Furthermore, main surfaces 211 and 222 will be described later. Figures 1-3 In the orthogonal coordinate system shown, the normal directions of principal surfaces 211 and 222 are defined as the z-axis direction, and the two parallel directions of the plane parallel to principal surfaces 211 and 222 and parallel to each side of the light diffraction structure 12 are defined as the x-axis direction and the y-axis direction.

[0012] like Figure 1 and Figure 2 As shown, the optical diffraction element unit U includes: an optical diffraction element 10 and a holding part 20.

[0013] Furthermore, in this embodiment, light with a wavelength λ of λ = 1.5 μm is used as the signal light. Additionally, the signal light is light with a two-dimensional intensity distribution on a plane orthogonal to its propagation direction. The optical diffraction structure 12, described later, has multiple micro-units A with independently set thicknesses or refractive indices, causing the signal light passing through each micro-unit A to interfere with each other, thereby performing a predetermined operation optically.

[0014] However, the wavelength λ is not limited to 1.5 μm and can be appropriately determined within the frequency band of electromagnetic waves. For example, this frequency band consists of the visible light region (360 nm and above, less than 830 nm), the near-infrared region (830 nm and above, less than 2 μm), the mid-infrared region (2 μm and above, less than 4 μm), and the far-infrared region (4 μm and above, less than 1000 μm). The wavelength λ can be at least a portion of the wavelengths included within the frequency band of 360 nm and above, less than 1000 μm. Signal light with λ = 1.5 μm is an example of light with a specific wavelength. Furthermore, during the design phase of the optical diffraction element unit U, the wavelength λ of the signal light is determined according to its intended use, etc. The light used as the signal light can be, for example, visible light or near-infrared light.

[0015] (Optical diffraction element) like Figure 3 As shown, the optical diffraction element 10 includes: a substrate 11 and an optical diffraction structure 12.

[0016] The substrate 11 is a layered component (e.g., a thin film) having opposing main surfaces 111 and 112, and is made of a light-transmitting material. Main surface 111 is an example of one of the main surfaces of the substrate 11. Furthermore, the portion of the substrate 11 located at the center of the main surface 111 will be referred to as the central portion 113, and the annular portion surrounding the central portion 113 will be referred to as the annular portion 114. Furthermore, in Figure 3 The underlined dotted line added to the reference numeral "113" in the attached figure indicates that the central part 113 is located in the lower layer of the light diffraction structure 12.

[0017] In this embodiment, an acrylic resin is used as the material constituting the substrate 11. However, the material constituting the substrate 11 is not limited to resins such as acrylic resins, as long as it is transparent in the wavelength range of the light used as signal light. The material constituting the substrate 11 can also be a glass material such as quartz glass.

[0018] Furthermore, the material constituting the substrate 11 is preferably a material that, when the light diffraction structure 12 described later is formed on the main surface 111, has good adhesion to the resin constituting the light diffraction structure 12 (e.g., a photocurable resin).

[0019] Furthermore, in this embodiment, the thickness of the substrate 11 is 5 μm. A resin film of this thickness is flexible and cannot be independently supported by monomers. However, the thickness of the substrate 11 is not limited to 5 μm.

[0020] Furthermore, viewed from the normal direction of the main surface 111, the shape of the substrate 11 (hereinafter referred to as the top view shape) is square, which is consistent with the top view shape of the retaining part 20 described later. Figure 1 In this embodiment, the size of the substrate 11 when viewed from above (i.e., the size of the outer edge of the annular portion 114) is equal to the size of the holding portion 20 when viewed from above. However, the size of the substrate 11 only needs to exceed the size of the central portion 113 described later, and can be appropriately determined within this range.

[0021] In an optical computing device A (reference) equipped with multiple optical diffraction element units U Figure 6In this embodiment, the spacing D between the periodically arranged optical diffraction structures 12 is approximately determined corresponding to the wavelength λ of the signal light. An example of this spacing D is D = 40λ. That is, in this embodiment where light with λ = 1.5 μm is used as the signal light, D = 60 μm. In this case, it is required that the sum of the thickness of the substrate 11, the maximum thickness of the optical diffraction structure 12, and the thickness of the holding portion 20 (described later) be 60 μm or less. The thickness of the substrate 11 can be appropriately determined within this range. Furthermore, even assuming a thickness of 60 μm for the substrate 11, the substrate 11 is flexible. Therefore, the present invention can be applied under these conditions, depending on the wavelength λ.

[0022] The light diffraction structure 12 is formed in the central portion 113. In this embodiment, the central portion 113 is, for example, a square of 200 μm × 200 μm. The light diffraction structure 12 is composed of a plurality of micro-units A with independently determined thicknesses or refractive indices (see reference). Figure 3 In this embodiment, each microunit A is made of a light-transmitting resin (e.g., a photocurable resin). However, the light diffraction structure 12 may also be made of glass (e.g., quartz glass).

[0023] When signal light is incident on the optical diffraction structure 12, the signal light passing through each micro-unit A interferes with each other, thereby performing a predetermined optical operation. The intensity distribution of the signal light output from the optical diffraction structure 12 represents the result of this optical operation.

[0024] Here, "microcell" refers to a cell with a size less than 10 μm. "Cell size" refers to the square root of the cell's area. For example, when the top view of a microcell is square, the cell size is the length of one side of the cell. There is no specific lower limit to the cell size; for example, it can be 1 nm.

[0025] Figure 1 The enlarged image illustrates a light diffraction structure 12 composed of 20×20 micro-units A arranged in a matrix. The top view shape of each micro-unit A is, for example, a 1μm×1μm square, and the top view shape of the light diffraction structure 12 is, for example, a 200μm×200μm square.

[0026] Furthermore, the unit size, the top view shape of each micro-unit A, and the top view shape of the optical diffraction structure 12 are not limited to the examples mentioned above, and can be appropriately determined.

[0027] (Maintenance Department) The holding part 20 is a layered or plate-shaped component (e.g., a foil) having opposing main surfaces 211 and 222. In this embodiment, the holding part 20 is composed of a first component 21 and a second component 22, wherein the first component 21 is a layered or plate-shaped component (e.g., a foil) having opposing main surfaces 211 and 212, and the second component 22 is a layered or plate-shaped component (e.g., a foil) having opposing main surfaces 221 and 222.

[0028] An opening 23 is provided on the retaining part 20, which penetrates a pair of main surfaces, namely main surfaces 211 and 222. In this embodiment, a first opening 213 penetrating a pair of main surfaces, namely main surfaces 211 and 212, is provided on the first component 21, and a second opening 223 penetrating a pair of main surfaces, namely main surfaces 221 and 222, is provided on the second component 22. The opening 23 is composed of the first opening 213 and the second opening 223.

[0029] The holding portion 20 holds the annular portion 114 in the substrate 11 in such a way that, when viewed from the normal direction of the main surface 211, the opening 23 includes the light diffraction structure 12. More specifically, the holding portion 20 holds the substrate 11 by clamping the annular portion 114 with the first component 21 and the second component 22.

[0030] In this embodiment, the main surface 111 of the substrate 11 and the main surface 212 of the first component 21 are utilized in Figure 1 and Figure 2 An adhesive layer (not shown) is used for fixation. Similarly, the main surface 112 of the substrate 11 and the main surface 221 of the second component 22 are utilized in... Figure 1 and Figure 2 The adhesive layers (not shown) are used for fixing. These adhesive layers are an example of a bonding method that joins the substrate 11, the first component 21, and the second component 22 together. However, the bonding method is not limited to adhesive layers and can be appropriately selected.

[0031] In this embodiment, aluminum alloy is used as the material constituting the retaining part 20. However, the material constituting the retaining part 20 is not limited to aluminum alloy, as long as it has higher rigidity than the substrate 11 in order to retain the substrate 11. Other metallic materials constituting the retaining part 20 include stainless steel and copper. In addition, the material constituting the retaining part 20 may also be a resin material such as glass fiber reinforced resin or carbon fiber reinforced resin.

[0032] Preferably, at least one of the pair of main surfaces 211 and 222 of the holding portion 20 has a higher absorption rate of signal light than aluminum. More preferably, the entire surface of the holding portion 20 has a higher absorption rate of signal light than aluminum. Furthermore, the absorption rate of signal light by the aluminum alloy can be considered to be the same as that of aluminum.

[0033] Furthermore, the aluminum surface used in defining the absorption rate can be a non-oxidized surface, but preferably an oxidized surface with a higher absorption rate. For example, when λ = 1 μm, the absorption rate of signal light from a non-oxidized aluminum surface is about 10%, while the absorption rate of signal light from an oxidized aluminum surface is about 40%. More preferably, the aluminum alloy of at least one of the pair of main surfaces 211 and 222, or the entire surface of the holding portion 20, has an absorption rate of 50% or more for signal light.

[0034] In this embodiment, the absorptivity of the entire surface of the holding portion 20 is greater than that of aluminum for signal light. Furthermore, the entire surface of the holding portion 20 is composed of a main surface 211, a main surface 212, the inner surface of the first opening 213, the outer surface of the first component 21, a main surface 221, a main surface 222, the inner surface of the second opening 223, and the outer surface of the second component 22. Similar to the main surfaces 211 and 222, the absorptivity of the main surfaces 212 and 221 is greater than that of aluminum for signal light. Therefore, when stray light propagating in the in-plane direction of the substrate 11 is generated for some reason, the main surfaces 212 and 221 can absorb the stray light. Thus, the optical diffraction element unit U can absorb the stray light before it propagates to the outer edge of the substrate 11, thereby suppressing stray light that may be emitted externally. Furthermore, the higher the absorptivity for signal light, the better the stray light can be suppressed.

[0035] Furthermore, there are no limitations on the structure for absorbing signal light. As a structure for absorbing signal light, a black coating film can be provided on the surface of the holding portion 20, or a metallic surface diffraction structure that absorbs light in the wavelength band λ containing the signal light can be provided. An example of a black coating film is a black coating film. Furthermore, the black coating film may also contain carbon black. Additionally, as in this embodiment, when the holding portion 20 is made of aluminum alloy, a black oxide layer formed by treating the surface of the holding portion 20 with black aluminum oxide can be used as a distinctive coating layer. Furthermore, when resin is used as the material constituting the holding portion 20, a resin that absorbs light in the wavelength band λ containing the signal light can also be used as the material.

[0036] In addition, such as Figure 2 As shown, the length L of one side of the opening 23 is used, and preferably the distance D from the opening 23 to the outer edge of the holding part 20 is used.H Satisfy D H ≧2 1 / 2 ×L. Furthermore, in this embodiment, the shape of the opening 23 is a square, corresponding to the shape of the central portion 113 and the light diffraction structure 12. However, the shape of the opening 23 is not limited to a square and can be appropriately determined. When the shape of the opening 23 is not a square, the square root of the area of ​​the opening 23 can be used as the opening size L instead of the length L of one side of the opening 23. Furthermore, the length L of one side of the opening 23 is an example of the opening size L.

[0037] In this embodiment, the holding part 20 is composed of a first component 21 and a second component 22. However, either the first component 21 or the second component 22 can be omitted from the holding part 20. Furthermore, when either the first component 21 or the second component 22 is omitted, the second component 22 is preferably omitted. When the second component 22 is omitted, the light diffraction structure 12 can be housed inside the first component 213, thus protecting the light diffraction structure 12 and preventing it from colliding with foreign objects.

[0038] (First variation) Reference Figure 4 The first variation of the optical diffraction element unit U, namely the optical diffraction element unit UA, will be used to illustrate this. Figure 4 This is a cross-sectional view of the optical diffraction element unit UA. Figure 4 The cross-section of the optical diffraction element unit UA shown is... Figure 2 Similarly, the cross-section of the light diffraction element unit U shown is a cross-section perpendicular to the opposing main surfaces 211B and 222B of the holding part 20, and is a cross-section through the light diffraction structure 12. Furthermore, Figure 4 The orthogonal coordinate system shown is in Figures 1-3 The orthogonal coordinate system shown in the figure is similarly determined.

[0039] The optical diffraction element unit UA can be obtained by deforming the substrate 11 constituting the optical diffraction element 10 into a substrate 11A based on the optical diffraction element unit U, and adding an absorption layer 30A. The following description focuses on the substrate 11A and the absorption layer 30A in the components of the optical diffraction element unit UA, omitting the description of components identical to those in the optical diffraction element unit U.

[0040] (Substrate) like Figure 4 As shown, substrate 11A is used to... Figure 2 The substrate 11 shown is formed by reducing its size through deformation. Furthermore, only the outer edge of the substrate 11 is reduced in size, while the size of the region where the light diffraction structure 12 is formed (the central portion 113 of the substrate 11) is the same as that of the substrate 11.

[0041] (Absorbing layer) When the substrate 11A is clamped by the first component 21 and the second component 22 during the deformation that reduces its size, an annular gap is formed between the first component 21 and the second component 22, and on the outer side of the substrate 11A. The absorption layer 30A is composed of resin filling the annular gap. The resin constituting the absorption layer 30A includes a resin or filler that absorbs light in the wavelength band λ containing signal light.

[0042] In the optical diffraction element unit U, when stray light propagating in the in-plane direction of the substrate 11 is generated for some reason, the stray light may propagate to the outer edge of the substrate 11 and be emitted to the outside of the optical diffraction element unit U.

[0043] In the optical diffraction element unit UA, even when stray light is emitted from the outer edge of the substrate 11A, the absorption layer 30A is able to absorb the stray light. Therefore, the optical diffraction element unit UA can suppress stray light that may be emitted to the outside.

[0044] (Second variation) Reference Figure 5 The second variation of the optical diffraction element unit U, namely the optical diffraction element unit UB, will be described. Figure 5 This is a cross-sectional view of the optical diffraction element unit UB. Figure 5 The cross-section of the optical diffraction element unit UB shown is... Figure 2 The cross-section of the light diffraction element unit U shown is also a cross-section perpendicular to the opposing main surfaces 211B and 222B of the holding part 20, and is a cross-section through the light diffraction structure 12. Furthermore, Figure 5 The orthogonal coordinate system shown is Figures 1-3 The orthogonal coordinate system shown is determined in the same way.

[0045] The optical diffraction element unit UB can be obtained by deforming the substrate 11 constituting the optical diffraction element 10 into a substrate 11A, and deforming the first component 21 into a first component 21B, based on the optical diffraction element unit U. Furthermore, the substrate 11A included in the optical diffraction element unit UB is the same as the substrate 11A included in the optical diffraction element unit UA. Therefore, the following description focuses on the first component 21B in the constituent parts of the optical diffraction element unit UB, omitting the description of components identical to those in the optical diffraction element unit U.

[0046] On the main surface 212B of the second component 22 side of the first component 21B, a recess 214B for accommodating the light diffraction element 10 is formed in connection with the first opening 213B. Furthermore, the first opening 213B corresponds to the first opening 213 of the first component 21.

[0047] According to this structure, even if stray light propagating in the in-plane direction of the substrate 11A is emitted from the outer edge of the substrate 11A, stray light emitted to the outside of the optical diffraction element unit UB can be suppressed.

[0048] Furthermore, in order to quickly absorb stray light propagating inside the recess 214B, it is preferable that the surface of the recess 214B, like the main surface 211 and the main surface 222, is configured to have a higher absorption rate for signal light than aluminum.

[0049] (Second Implementation) (Structure of the optical computing device) Reference Figure 6 The optical computing device A according to the second embodiment of the present invention will be described. Figure 6 This is a cross-sectional view of optical computing device A. Figure 6 The cross-section of the optical computing device A shown is... Figure 2 The cross-section of the light diffraction element unit U shown is also a cross-section perpendicular to the opposing main surfaces 211 and 222 of the holding portion 20 of each light diffraction element unit U, and is a cross-section through the light diffraction structure 12.

[0050] like Figure 6 As shown, the optical processing device A includes three optical diffraction element units U1, U2, and U3, and a housing 40 for housing the optical diffraction element units U1, U2, and U3. Each optical diffraction element unit U1, U2, and U3 is an example of the first to Nth optical diffraction element units (N is an integer of 2 or more) described in the first embodiment. In this embodiment, numbers are added to the end of the reference numerals to distinguish each of the three optical diffraction element units U. Furthermore, the number of optical diffraction element units U included in the optical processing device A is not limited to three, and can be appropriately determined within a range of two or more.

[0051] In this embodiment, the description of the optical diffraction element units U1, U2, and U3 is omitted, and the housing 40 is described instead.

[0052] In this embodiment, aluminum alloy is used as the material constituting the housing 40. However, the material constituting the housing 40 is not limited to aluminum alloy, as long as it has sufficient rigidity to maintain each optical diffraction element unit U1, U2, and U3. Other metallic materials constituting the housing 40 include stainless steel and copper. In addition, the material constituting the housing 40 may also be a resin material such as glass fiber reinforced resin or carbon fiber reinforced resin.

[0053] The shell 40 is a rectangular box with internal cavities. For example... Figure 6As shown, the housing 40 includes: a pair of bottom walls 41 and 42 facing each other, and a side wall 43 located between the bottom walls 41 and 42.

[0054] The bottom wall 41 includes a pair of opposing main faces, namely main face 411 and main face 412. Similarly, the bottom wall 42 includes a pair of opposing main faces, namely main face 421 and main face 422.

[0055] The side wall 43 is a cylindrical component with a square cross-section. The side wall 43 includes an inner side surface 431 and an outer side surface 432 that are opposite to each other. The bottom wall 41 and the bottom wall 42 are respectively connected to the openings provided at both ends of the side wall 43.

[0056] Openings 413 and 423 are respectively provided near the center of each of the bottom walls 41 and 42. The shape and size of the openings 413 and 423 can be appropriately determined to correspond to the shape and size of the light diffraction structure 12. In this embodiment, when the openings 413 and 423 are viewed from the normal direction (z-axis direction) of the main surface 211, the openings 413 and 423 are square in shape. In addition, in this embodiment, the size of the openings 413 and 423 is determined in such a way that the light diffraction structure 12 is included when the openings 413 and 423 are viewed from above.

[0057] A groove is provided on the inner surface 431 of the sidewall 43 to hold each optical diffraction element unit U1, U2, and U3. The width of each groove is approximately equal to the thickness of each optical diffraction element unit U1, U2, and U3. Each groove is parallel to the bottom walls 41 and 42 and is arranged in a ring around the entire circumference of the inner surface 431. In the optical processing device A, each optical diffraction element unit U1, U2, and U3 is held by the sidewall 43 by inserting each groove into it.

[0058] The spacing between adjacent slots is determined such that the spacing D between the optical diffraction structures 12 in the optical processing device A is a predetermined value (e.g., D = 60 μm (= 40λ)). Furthermore, Figure 6 The three dashed lines shown represent the positions of the optical diffraction element units U1, U2, and U3 in the thickness direction (z-axis direction).

[0059] In the optical computing device A, each optical diffraction element unit U1, U2, U3 is positioned along a pair of principal surfaces of the substrate 11. Figure 2 The normal directions (z-axis direction) of the main surfaces 111 and 112 are sequentially and coincidentally housed inside the shell 40.

[0060] Furthermore, in this embodiment, for the surfaces of the housing 40 (main surfaces 411, 412, the inner surface of the opening 413, main surfaces 421, 422, the inner surface of the opening 423, the inner surface 431, and the outer surface 432), regardless of whether they are inner or outer surfaces, all are configured to have a higher absorption rate for signal light than that of aluminum. As a structure for absorbing this signal light, similar to the case of the holding part 20, a black coating film can be provided on the surface of the housing 40, or a metal surface diffraction structure that absorbs light in the wavelength band containing the signal light λ can be provided. As an example of a black coating film, a black coating film can be used. Furthermore, the black coating film may also contain carbon black. Additionally, as in this embodiment, when the housing 40 is made of aluminum alloy, a black oxide layer formed by treating the surface of the housing 40 with black aluminum oxide can also be used as a distinctive coating layer. In addition, when resin is used as the material constituting the housing 40, a resin that absorbs light in the wavelength band containing the signal light λ can also be used as the material.

[0061] However, the structure for absorbing signal light on the surface of housing 40 may be omitted, or it may only be provided in a designated area on the surface of housing 40. When the structure for absorbing signal light is provided only in a designated area on the surface of housing 40, an example of the designated area is the inner wall of housing 40 (main surface 412, main surface 421, and inner surface 431). In addition to the inner wall of housing 40, the structure for absorbing signal light may also be provided on the inner surface of opening 413 and the inner surface of opening 423.

[0062] (Summarize) The optical diffraction element unit of the first embodiment of the present invention comprises: a substrate, which is a layered component having light transmittance and flexibility; an optical diffraction structure formed on a portion of a main surface of the substrate, comprising a plurality of micro-units; and a holding portion, which is a layered or plate-shaped component provided with an opening penetrating a pair of main surfaces, holding the substrate. In this optical diffraction element unit, the following structure is adopted: the holding portion holds an annular portion of the substrate surrounding the portion of the substrate such that the opening includes the optical diffraction structure.

[0063] According to the above structure, the opening includes the light diffraction structure, therefore, light of a specific wavelength having the transmitted light diffraction structure is not affected by the holding portion. Furthermore, the holding portion holds the annular portion in the substrate. Therefore, the main surface shape of the substrate remains planar. In this way, this light diffraction element unit can maintain the main surface shape of the substrate as planar.

[0064] In addition, in the optical diffraction element unit of the second aspect of the present invention, besides the structure of the optical diffraction element unit of the first aspect described above, the following structure is also adopted: at least one of the pair of main surfaces of the holding part has a greater absorption rate for light with a specific wavelength than aluminum has for that light.

[0065] According to the above structure, at least one of the pair of main surfaces of the holding portion absorbs light of a specific wavelength more strongly than aluminum. Therefore, when stray light accompanying light of a specific wavelength is incident on one of the main surfaces of the holding portion, at least a portion of the stray light is absorbed by that main surface. Thus, this optical diffraction element unit can suppress stray light accompanying light of a specific wavelength that is capable of transmitting through the optical diffraction element unit.

[0066] Furthermore, the specific wavelength is a wavelength included in the electromagnetic spectrum and can be appropriately determined during the design phase of the optical diffraction element unit based on its intended use. For example, it may be within a frequency band of 360 nm to 1000 μm. This frequency band comprises the visible light region (360 nm to less than 830 nm), the near-infrared region (830 nm to less than 2 μm), the mid-infrared region (2 μm to less than 4 μm), and the far-infrared region (4 μm to less than 1000 μm). The specific wavelength can be at least a portion of the wavelengths included within the frequency band of 360 nm to 1000 μm.

[0067] In addition, in the optical diffraction element unit of the third aspect of the present invention, besides the structure of the optical diffraction element unit of the first or second aspect described above, the following structure is also adopted: the entire surface of the holding part has a greater absorption rate for light with a specific wavelength than the absorption rate of aluminum for that light.

[0068] Based on the above structure, stray light that is attached to and can transmit through the light diffraction element unit in light of a specific wavelength can be reliably suppressed.

[0069] In addition, in the optical diffraction element unit of the fourth embodiment of the present invention, besides the structure of the optical diffraction element unit of any of the first to third embodiments described above, the following structure is also adopted: the holding part includes a first component and a second component, the first component and the second component are layered or plate-shaped, the first component and the second component are respectively provided with an opening penetrating a pair of main surfaces, the first component and the second component clamp the annular portion, thereby the holding part holds the annular portion.

[0070] According to the above structure, even if stray light propagating in the in-plane direction toward the main surface of the substrate is generated, the stray light will be guided between the first and second components. Therefore, it is possible to suppress the leakage of stray light propagating in the in-plane direction toward the main surface of the substrate toward the subsequent optical diffraction element unit.

[0071] Furthermore, in the optical diffraction element unit of the fifth embodiment of the present invention, in addition to the structure of the optical diffraction element unit of any of the first to fourth embodiments described above, the following structure is also adopted: the square root of the area of ​​the opening is set as the opening size L, and the distance D from the opening to the outer edge of the holding portion is... H Satisfy D H ≧2 1 / 2 ×L.

[0072] Based on the above structure, stray light that is attached to and can transmit through the light diffraction element unit in light of a specific wavelength can be reliably suppressed.

[0073] The optical computing device according to the sixth aspect of the present invention comprises: a first optical diffraction element unit to an Nth optical diffraction element unit (N is an integer greater than or equal to 2), wherein the optical diffraction element units are optical diffraction element units of any of the first to fifth aspects described above; and a housing that sequentially houses each of the first to Nth optical diffraction element units along the normal direction of one main surface of the substrate.

[0074] Based on the above structure, an optical computing device having a plurality of optical diffraction element units according to a first aspect of the present invention can be provided, thereby achieving the same effect as the optical diffraction element unit according to a first aspect of the present invention.

[0075] In addition, in the optical computing device of the seventh embodiment of the present invention, besides the structure of the optical computing device of the sixth embodiment described above, the following structure is also adopted: the inner wall of the housing has a greater absorption rate for light with a specific wavelength than the absorption rate of aluminum for that light.

[0076] Based on the above structure, it is possible to suppress stray light that is attached to light of a specific wavelength and can propagate within the optical processing device.

[0077] (Additional Notes) This invention is not limited to the embodiments described above. Various modifications can be made 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 this invention. Explanation of reference numerals in the attached figures

[0078] A - Optical computing device; U, UA, UB, U1, U2, U3 - Optical diffraction element units; 10 - Optical diffraction element; 11, 11A, 11B - Substrate; 111 - Main surface (one main surface); 112 - Main surface; 113 - Central part (part of one main surface of the substrate); 114 - Annular part; 12 - Optical diffraction structure; 20 - Holding part; 23 - Opening; 21, 21B - First component; 211, 212, 211B, 212B - Main surface; 213, 213B - First opening; 22 - Second component; 221, 222 - Main surface; 223 - Second opening; 40 - Housing; 41, 42 - Bottom wall; 411, 412, 421, 422 - Main surface; 413, 423 - Opening; 43 - Side wall; 431, 432 - Inner surface, outer surface.

Claims

1. A light diffraction element unit, characterized in that, have: The substrate is a layered component that is transparent and flexible; A light diffraction structure, formed on a portion of a main surface of the substrate, comprising multiple micro-units with independently determined thicknesses or refractive indices; as well as A retaining part is a layered or plate-shaped component with an opening extending through a pair of main surfaces, which retains the substrate. The retaining portion holds the annular portion surrounding the portion in the substrate in such a way that the opening contains the light diffraction structure.

2. The optical diffraction element unit according to claim 1, characterized in that, At least one of the pair of main surfaces of the retaining part has a greater absorption rate for light of a specific wavelength than aluminum has for that light.

3. The optical diffraction element unit according to claim 1, characterized in that, The entire surface of the retaining part has a greater absorption rate for light of a specific wavelength than aluminum does for that light.

4. The optical diffraction element unit according to any one of claims 1 to 3, characterized in that, The retaining part includes a first component and a second component, which are layered or plate-shaped. The first component and the second component are respectively provided with an opening penetrating a pair of main surfaces. The first component and the second component clamp the annular portion, thereby the retaining part retains the annular portion.

5. The optical diffraction element unit according to any one of claims 1 to 3, characterized in that, The square root of the area of ​​the opening is set as the opening size L. The distance D from the opening to the outer edge of the retaining part H Satisfy D H ≥2 1 / 2 ×L.

6. An optical computing device, characterized in that, have: The first to the Nth optical diffraction element units, wherein these optical diffraction element units are the optical diffraction element units as described in any one of claims 1 to 5, and N is an integer greater than or equal to 2; and The housing sequentially houses the first to the Nth optical diffraction element units along the normal direction of one of the main surfaces of the substrate.

7. The optical computing device according to claim 6, characterized in that, The inner wall of the housing has a higher absorption rate for light of a specific wavelength than aluminum does for that light.

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