Optical computing device and manufacturing method thereof

Abstract

To provide an optical computing device which makes it easy to maintain a desired relative positional relationship among planar light diffraction elements.SOLUTION: An optical computing device (1) is provided, comprising a substrate (12), a plurality of planar light diffusion elements (11a1-11a4), a cover (15), and a sidewall, where each planar light diffraction element (11a1-11a4) consists of multiple micro-cells with independently set thicknesses or refractive indices and is fixed onto the substrate (12).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an optical computing device including a plurality of planar optical diffraction elements, and also to a method for manufacturing such an optical computing device. [Background technology]

[0002] Patent Document 1 discloses a technique for fixing each of a plurality of optical elements (specifically, lenses) arranged side by side to a cylindrical holder (specifically, a lens holder). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2018-527829 Summary of the Invention [Problem to be solved by the invention]

[0004] Planar optical diffraction elements having multiple microcells with individually set thicknesses or refractive indices are known as optical elements having an optical calculation function. By using an optical calculation device in which such planar optical diffraction elements are arranged on the optical path of a signal light, it is possible to perform complex optical calculations at high speed with low power consumption. However, when multiple planar optical diffraction elements constituting an optical calculation device are fixed to a cylindrical holder by applying the technology described in Patent Document 1, the following problems arise.

[0005] That is, when the environmental temperature changes, the holder is distorted due to thermal expansion or contraction. Since each planar optical diffraction element is fixed to the inner surface of the holder over the entire circumference, when the holder is distorted, it is difficult to avoid the occurrence of distortion or stress in each planar optical diffraction element. When distortion or stress occurs in each planar optical diffraction element, it becomes difficult or impossible to make the planar optical diffraction element perform the intended operation. As a result, it becomes difficult or impossible to make the planar optical diffraction elements perform the intended operation as a whole.

[0006] One aspect of the present invention has been made in consideration of the above problems, and has an object to provide an optical arithmetic device that can easily maintain its arithmetic function even when the environmental temperature changes. [Means for solving the problem]

[0007] In order to solve the above problems, an optical computing device according to one embodiment of the present invention comprises a substrate, an optical diffraction element group including a plurality of planar optical diffraction elements, a cover facing the substrate and supported so as not to come into contact with each of the planar optical diffraction elements belonging to the optical diffraction element group, and sidewalls surrounding the optical diffraction element group on all sides, one end being fixed to an upper surface of the substrate and the other end being fixed to a lower surface of the cover, wherein each planar optical diffraction element belonging to the optical diffraction element group is composed of a plurality of microcells whose thicknesses or refractive indices are set independently of each other, and is fixed to the substrate.

[0008] In order to solve the above problem, a manufacturing method for an optical computing device according to one embodiment of the present invention is a manufacturing method for the above-mentioned optical computing device, which includes a step of collectively forming each planar optical diffraction element belonging to the optical diffraction element group. Effect of the Invention

[0009] According to one aspect of the present invention, it is possible to realize an optical arithmetic device that can easily maintain its arithmetic function even if the environmental temperature changes. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view showing a configuration of an optical calculation device according to a first embodiment of the present invention. [Diagram 2] 2 is a perspective view showing a specific example of a planar optical diffraction element included in the optical computing device shown in FIG. 1. [Diagram 3] FIG. 11 is a perspective view showing a configuration of an optical calculation device according to a second embodiment of the present invention. [Figure 4] FIG. 11 is a perspective view showing a configuration of an optical calculation device according to a third embodiment of the present invention. [Diagram 5] FIG. 11 is a perspective view showing a configuration of an optical calculation device according to a fourth embodiment of the present invention. [Figure 6] FIG. 13 is a perspective view showing a configuration of an optical calculation device according to a fifth embodiment of the present invention. [Figure 7] FIG. 13 is a perspective view showing a configuration of an optical calculation device according to a sixth embodiment of the present invention. [Figure 8] FIG. 13 is a perspective view showing a modified example of the optical calculation device according to the sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [First embodiment] (Configuration of Optical Computing Unit) The configuration of an optical arithmetic device 1 according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a perspective view showing the configuration of the optical arithmetic device 1.

[0012] The optical computing device 1 includes an optical diffraction element group 11 and a substrate 12. The optical diffraction element group 11 is composed of a plurality of (four in this embodiment) planar optical diffraction elements 11a1-11a4. In this embodiment, the planar optical diffraction elements 11a1-11a4 are made of resin and have a plate-like shape with a square shape in a plan view. In this embodiment, the substrate 12 is made of glass and has a plate-like shape with a rectangular shape in a plan view.

[0013] The end faces of the planar optical diffraction elements 11a1 to 11a4 are fixed directly to the main surface of the substrate 12 so that the entrance surface and exit surface of each of the planar optical diffraction elements 11a1 to 11a4 intersect with the main surface of the substrate 12 (orthogonal to each other in this embodiment).

[0014] Each planar optical diffraction element 11ai (i=1, 2, ..., 4) is composed of a plurality of microcells whose thickness or refractive index is set independently of each other. When signal light is incident on the optical calculation device 1, the signal light with different phases transmitted through each microcell interferes with each other, thereby performing a predetermined optical calculation. In this specification, the term "microcell" refers to a cell having a cell size of less than 10 μm, for example. In this specification, the term "cell size" refers to the square root of the area of ​​the cell. For example, when the shape of the microcell in plan view is a square, 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.

[0015] In this embodiment, the planar optical diffraction elements 11a1 to 11a4 are arranged in a straight line on the optical path of the signal light input to the optical calculation device 1. Therefore, the signal light input to the optical calculation device 1 passes through the first planar optical diffraction element 11a1, the second planar optical diffraction element 11a2, the third planar optical diffraction element 11a3, and the fourth planar optical diffraction element 11a4 in this order. Therefore, in the optical calculation device 1, the first optical calculation by the first planar optical diffraction element 11a1, the second optical calculation by the second planar optical diffraction element 11a2, the third optical calculation by the third planar optical diffraction element 11a3, and the fourth optical calculation by the fourth planar optical diffraction element 11a4 are executed in this order.

[0016] The optical computing device 1 may include a plate-shaped cover 15 (indicated by a dotted line in FIG. 1) disposed so as to face the substrate 12. For example, the cover 15 is supported by at least three posts (not shown in FIG. 1) having one end fixed to the upper surface of the substrate 12 and the other end fixed to the lower surface of the cover 15. Alternatively, the cover 15 is supported by side walls (not shown in FIG. 1) surrounding the optical diffraction element group 11 from all sides, having one end fixed to the upper surface of the substrate 12 and the other end fixed to the lower surface of the cover 15. The height of the posts or side walls is set to be sufficiently high so that the lower surface of the cover 15 does not come into contact with the upper end surfaces of the planar optical diffraction elements 11ai.

[0017] Here, the upper surface of the substrate 12 refers to the main surface to which the planar optical diffraction elements 11a1 to 11a4 are fixed, out of the two main surfaces of the substrate 12. The lower surface of the cover 15 refers to the main surface facing the main surface of the substrate 12, out of the two main surfaces of the cover 15. The upper end surface of the planar optical diffraction element 11ai refers to the end surface facing the end surface fixed to the upper surface of the substrate 12, out of the four end surfaces of the planar optical diffraction element 11ai. When a configuration is adopted in which the cover 15 is supported by the side wall, it is also possible to fill the space surrounded by the substrate 12, the cover 15, and the side wall with a liquid such as matching oil or a gas such as nitrogen gas.

[0018] (Specific example of a planar optical diffraction element) A specific example of each planar optical diffraction element 11ai included in the optical processing device 1 will be described with reference to Fig. 2. Fig. 2 is a perspective view of the planar optical diffraction element 11ai according to this specific example.

[0019] The planar optical diffraction element 11ai according to this specific example has a square effective area with each side being 1.0 mm. This effective area is composed of 100 x 100 microcells arranged in a matrix. Each microcell is composed of a rectangular pillar having a square bottom with each side being 1 μm, formed on a base with a thickness of 100 μm. The height of each pillar is 0 nm, 100 nm, 200 nm, ..., 1100 nm, 1200 nm (13 levels in 100 nm steps), and is determined so that the phase change amount of light passing through the microcell composed of the pillar becomes a desired value.

[0020] In the planar light diffraction element 11ai according to this specific example, pillars are provided only on one main surface of the base, but the present invention is not limited to this. That is, pillars may be provided on both main surfaces of the base. In addition, the planar light diffraction element 11a1 in which pillars are provided only on one main surface of the base can be arranged in the optical processing device 1 so that the pillar-formed surface is the incident surface of the signal light, or the pillar-formed surface is the exit surface of the signal light. On the other hand, the planar light diffraction element 11a1 in which pillars are provided on both main surfaces of the base can be arranged in the optical processing device 1 so that one pillar-formed surface is the incident surface of the signal light, and the other pillar-formed surface is the exit surface of the signal light.

[0021] In the planar light diffraction element 11ai according to this specific example, the thickness of each microcell (i.e., the height of the pillar constituting each microcell) is set so that the phase change amount of the light passing through each microcell is a desired value, but the present invention is not limited to this. For example, the refractive index of each microcell may be set so that the phase change amount of the light passing through each microcell is a desired value. In this case, the refractive index of each microcell may be set by selecting the material of the microcell, or by selecting the type and / or amount of an additive to be added to the material of the microcell. In addition, when each microcell is made of a resin (polymer), the refractive index of the microcell may be set by controlling the degree of polymerization of the resin.

[0022] (Effect of optical computing device) As described above, the optical computing device 1 includes the substrate 12 and the optical diffraction element group 11 including the plurality of planar optical diffraction elements 11a1-11a4. Each planar optical diffraction element 11ai belonging to the optical diffraction element group 11 is composed of a plurality of microcells whose thicknesses or refractive indices are set independently of one another, and is fixed to the substrate 12 such that its entrance surface and exit surface intersect with the main surface of the substrate 12.

[0023] Therefore, in the optical calculation device 1, only a part (one end face) of the outer periphery (four end faces) of each planar optical diffraction element 11ai is fixed to the substrate 12, and the remaining parts (three end faces) are free. Therefore, compared to the case where the entire outer periphery of each planar optical diffraction element 11ai is fixed to the inner surface of a cylindrical holder by utilizing the technology described in Patent Document 1, distortion or stress caused by changes in environmental temperature is less likely to occur in each planar optical diffraction element 11ai. Therefore, it is possible to realize an optical calculation device 1 that can easily maintain its calculation function even if the environmental temperature changes.

[0024] The optical calculation device 1 may further include a cover 15 that faces the substrate 12 and is supported so as not to come into contact with the planar optical diffraction elements 11ai belonging to the optical diffraction element group 11.

[0025] In this case, according to the optical calculation device 1, it is possible to protect each planar optical diffraction element 11ai from shocks, vibrations, and the like that may be applied to each planar optical diffraction element 11ai from the outside of the optical calculation device 1. In addition, it is possible to protect each planar optical diffraction element 11ai from foreign matter that may fly into the optical calculation device 1.

[0026] The optical diffraction element group 11 may also include a planar optical diffraction element having a plurality of pillars, the heights of which are set independently of one another, formed on both sides.

[0027] In a planar optical diffraction element having pillars formed on both sides, it is possible to form a cell having a larger phase change amount (i.e., a thicker thickness) than a planar optical diffraction element having pillars formed on one side. Therefore, the degree of freedom of optical calculations that can be executed by a planar optical diffraction element having pillars formed on both sides is higher than the degree of freedom of optical calculations that can be executed by a planar optical diffraction element having pillars formed on one side. Therefore, by including a planar optical diffraction element having pillars formed on both sides in the optical diffraction element group 11, the degree of freedom of optical calculations that can be executed by the optical calculation device 1 can be increased.

[0028] As a manufacturing method for the optical calculation device 1, a manufacturing method including a step of forming each of the planar optical diffraction elements 11ai belonging to the optical diffraction element group 11 all at once can be used.

[0029] When such a manufacturing method is adopted, it is possible to omit the adjustment process of adjusting the position and orientation of each planar optical diffraction element 11ai so that the relative positional relationship of each planar optical diffraction element 11ai becomes a desired relationship, which is necessary when each planar optical diffraction element 11ai is formed separately. Therefore, according to such a manufacturing method, the relative positional relationship of each planar optical diffraction element 11ai can be easily maintained in a desired relationship.

[0030] The process of collectively forming each of the planar optical diffraction elements 11ai belonging to the optical diffraction element group 11 can be realized by, for example, a nanoimprint method or a photolithography method. The photolithography method is also called a liquid phase photopolymerization method.

[0031] Second Embodiment (Configuration of Optical Computing Unit) The configuration of an optical arithmetic device 2 according to a second embodiment of the present invention will be described with reference to Fig. 3. Fig. 3 is a perspective view showing the configuration of the optical arithmetic device 2.

[0032] The optical calculation device 2 includes an optical diffraction element group 21, a substrate 22, and a prism 23. The optical diffraction element group 21 is composed of a plurality of (four in this embodiment) planar optical diffraction elements 21a1-21a4. In this embodiment, the planar optical diffraction elements 21a1-21a4 are made of resin and have a plate-like shape with a square shape in a plan view. In this embodiment, the substrate 22 is made of glass and has a plate-like shape with a rectangular shape in a plan view. In this embodiment, the prism 23 is a right-angle prism having two mutually orthogonal reflecting surfaces 23a and 23b.

[0033] The first planar optical diffraction element 21a1 and the second planar optical diffraction element 21a2 have their end faces directly fixed to the main surface of the substrate 22 such that their incident and exit surfaces intersect (orthogonal in this embodiment) with the main surface of the substrate 22. The third planar optical diffraction element 21a3 is indirectly fixed to the main surface of the substrate 22 via the second planar optical diffraction element 21a2 such that its incident and exit surfaces intersect (orthogonal in this embodiment) with the main surface of the substrate 22. The fourth planar optical diffraction element 21a4 is indirectly fixed to the main surface of the substrate 22 via the first planar optical diffraction element 21a1 such that its incident and exit surfaces intersect (orthogonal in this embodiment) with the main surface of the substrate 22.

[0034] Each planar optical diffraction element 21ai (i=1, 2, 3, 4) is composed of a plurality of microcells whose thickness or refractive index is set independently of each other. When signal light is incident on the optical calculation device 2, the signal light having different phases transmitted through each microcell interferes with each other to perform a predetermined optical calculation. A specific example of each planar optical diffraction element 21ai is similar to the specific example of each planar optical diffraction element 11ai included in the optical calculation device 1 according to the first embodiment, and therefore a description thereof will be omitted here.

[0035] In this embodiment, the first planar optical diffraction element 21a1 and the second planar optical diffraction element 21a2 are arranged in a straight line on the optical path of the signal light input to the optical calculation device 2. Therefore, the signal light input to the optical calculation device 2 passes through the first planar optical diffraction element 21a1 and the second planar optical diffraction element 21a2 in this order. The first reflecting surface 23a of the prism 23 is arranged on the optical path of the signal light that has passed through the second planar optical diffraction element 21a2. The first reflecting surface 23a of the prism 23 reflects the signal light that has passed through the second planar optical diffraction element 21a2 so as to change its traveling direction by 90° within a plane that intersects with the main surface of the substrate 22 (orthogonal in this embodiment). The second reflecting surface 23b of the prism 23 is arranged on the optical path of the signal light reflected by the first reflecting surface 23a of the prism 23. The second reflecting surface 23b of the prism 23 reflects the signal light reflected by the first reflecting surface 23a of the prism 23 so as to change the traveling direction of the signal light by 90° in a plane intersecting (orthogonal in this embodiment) the main surface of the substrate 22. That is, the prism 23 reflects the signal light that has passed through the second planar optical diffraction element 21a2 in a direction opposite to the traveling direction of the signal light via the first reflecting surface 23a and the second reflecting surface 23b. On the optical path of the signal light reflected by the second reflecting surface 23b of the prism 23, the third planar optical diffraction element 21a3 and the fourth planar optical diffraction element 21a4 are arranged in a straight line. Therefore, the signal light reflected by the second reflecting surface 23b of the prism 23 passes through the third planar optical diffraction element 21a3 and the fourth planar optical diffraction element 21a4 in this order. Therefore, in the optical calculation device 2, a first optical calculation by the first planar optical diffraction element 21a1, a second optical calculation by the second planar optical diffraction element 21a2, a third optical calculation by the third planar optical diffraction element 21a3, and a fourth optical calculation by the fourth planar optical diffraction element 21a4 are executed in this order.

[0036] (Effect of optical computing device) As described above, the optical computing device 2 further includes the prism 23 that functions as an optical element that turns back the optical path of the signal light within a plane intersecting with the main surface of the substrate 22. The optical diffraction element group 21 includes planar optical diffraction elements 21a1 and 21a2 that are provided in the optical path before turning back and are directly fixed to the substrate 22, and planar optical diffraction elements 21a4 and 21a3 that are provided in the optical path after turning back and are indirectly fixed to the substrate 22 via the planar optical diffraction elements 21a1 and 21a2.

[0037] Therefore, according to the optical arithmetic device 2, it is possible to increase the mounting density when the planar optical diffraction elements 21a1, 21a2, 21a3, and 21a4 are mounted on the substrate 22. Therefore, according to the optical arithmetic device 2, it is possible to reduce the size of the substrate 22 compared to the optical arithmetic device 1.

[0038] Third embodiment (Configuration of Optical Computing Unit) The configuration of an optical arithmetic device 3 according to a third embodiment of the present invention will be described with reference to Fig. 4. Fig. 4 is a perspective view showing the configuration of the optical arithmetic device 3.

[0039] The optical calculation device 3 includes an optical diffraction element group 31, a substrate 32, a prism 33, and a mirror 34. The optical diffraction element group 31 is composed of a plurality of (four in this embodiment) planar optical diffraction elements 31a1-31a4. In this embodiment, the planar optical diffraction elements 31a1-31a4 are made of resin and have a plate-like shape with a square shape in a plan view. In this embodiment, the substrate 32 is made of glass and has a plate-like shape with a rectangular shape in a plan view. In this embodiment, the prism 33 is a right-angle prism having two mutually orthogonal reflecting surfaces 33a and 33b.

[0040] The end faces of the planar optical diffraction elements 31a1 to 31a4 are fixed directly to the main surface of the substrate 32 so that the entrance surface and exit surface of each of the planar optical diffraction elements 31a1 to 31a4 intersect with the main surface of the substrate 32 (orthogonal in this embodiment).

[0041] Each planar optical diffraction element 31ai (i=1, 2, 3, 4) is composed of a plurality of microcells whose thickness or refractive index is set independently of each other. When signal light is incident on the optical calculation device 3, the signal light having different phases transmitted through each microcell interferes with each other to perform a predetermined optical calculation. A specific example of each planar optical diffraction element 31ai is similar to the specific example of each planar optical diffraction element 11ai (i=1, 2, 3, 4) included in the optical calculation device 1 according to the first embodiment, and therefore a description thereof will be omitted here.

[0042] In this embodiment, a first planar optical diffraction element 31a1 is disposed on the optical path of the signal light input to the optical calculation device 3. Therefore, the signal light input to the optical calculation device 3 passes through the first planar optical diffraction element 31a1. A first reflecting surface 33a of the prism 33 is disposed on the optical path of the signal light that has passed through the first planar optical diffraction element 31a1. The first reflecting surface 33a of the prism 33 reflects the signal light that has passed through the first planar optical diffraction element 31a1 so as to change its traveling direction by 90° in a plane parallel to the main surface of the substrate 32. A second reflecting surface 33b of the prism 33 is disposed on the optical path of the signal light reflected by the first reflecting surface 33a of the prism 33. The second reflecting surface 33b of the prism 33 reflects a portion of the signal light reflected by the first reflecting surface 33a of the prism 33 so as to change the traveling direction of the signal light by a further 90° in a plane parallel to the main surface of the substrate 32. In addition, the second reflecting surface 33b of the prism 33 transmits a portion of the signal light reflected by the first reflecting surface 33a of the prism 33.

[0043] The second planar optical diffraction element 31a2 is disposed on the optical path of the signal light reflected by the second reflecting surface 33b of the prism 33. Therefore, the signal light reflected by the second reflecting surface 33b of the prism 33 passes through the second planar optical diffraction element 31a2. Therefore, in the optical calculation device 3, the first optical calculation by the first planar optical diffraction element 31a1 and the second optical calculation by the second planar optical diffraction element 31a2 are executed in this order.

[0044] A mirror 34 is disposed on the optical path of the signal light transmitted through the second reflecting surface 33b of the prism 33. The mirror 34 reflects the signal light transmitted through the second reflecting surface 33b of the prism 33 so as to change the traveling direction of the signal light by 90° in a plane parallel to the main surface of the substrate 32. On the optical path of the signal light reflected by the mirror 34, the third planar optical diffraction element 31a3 and the fourth planar optical diffraction element 31a4 are disposed in a line. Therefore, the signal light reflected by the mirror 34 passes through the third planar optical diffraction element 31a3 and the fourth planar optical diffraction element 31a4 in this order. Therefore, in the optical calculation device 3, the first optical calculation by the first planar optical diffraction element 31a1, the third optical calculation by the third planar optical diffraction element 31a3, and the fourth optical calculation by the fourth planar optical diffraction element 31a4 are executed in this order.

[0045] (Effect of optical computing device) As described above, the optical calculation device 3 includes the prism 33 and the mirror 34 that function as optical elements that split the optical path of the signal light into a first optical path (optical path A in FIG. 4) and a second optical path (optical path B in FIG. 4). The optical diffraction element group 31 includes the planar optical diffraction element 31a2 provided on the first optical path, and the planar optical diffraction elements 31a3 and 31a4 provided on the second optical path.

[0046] Therefore, the optical arithmetic device 3 can split one optical path into two optical paths A and B, and perform separate optical calculations on each of the optical paths A and B. In other words, the optical arithmetic device 3 can simultaneously execute multiple (two in this embodiment) optical calculations.

[0047] [Fourth embodiment] (Configuration of Optical Computing Unit) The configuration of an optical arithmetic device 4 according to the fourth embodiment of the present invention will be described with reference to Fig. 5. Fig. 5 is a perspective view showing the configuration of the optical arithmetic device 4.

[0048] The optical calculation device 4 includes an optical diffraction element group 41, a substrate 42, and a mirror 43. The optical diffraction element group 41 is composed of a plurality of (six in this embodiment) planar optical diffraction elements 41a1 to 41a6. In this embodiment, the planar optical diffraction elements 41a1 to 41a6 are made of resin and are plate-shaped members having a square shape in a plan view. In this embodiment, the substrate 42 is made of glass and is plate-shaped members having a rectangular shape in a plan view. In this embodiment, the mirror 43 is configured to be rotatable about an axis perpendicular to the main surface of the substrate 42. FIG. 5 illustrates a configuration in which a cylindrical protrusion 43a protruding from an end face of the mirror 43 is inserted into a cylindrical hole formed in the upper surface of the substrate 42, thereby rotatably fixing the mirror 43 to the substrate 42.

[0049] The end faces of the planar optical diffraction elements 41a1 to 41a6 are fixed directly to the main surface of the substrate 42 so that the entrance surface and exit surface of each of the planar optical diffraction elements 41a1 to 41a6 intersect with the main surface of the substrate 42 (orthogonal in this embodiment).

[0050] Each planar optical diffraction element 41ai (i=1, 2, ..., 6) is composed of a plurality of microcells whose thickness or refractive index is set independently of each other. When signal light is incident on the optical calculation device 4, the signal light having different phases transmitted through each microcell interferes with each other to perform a predetermined optical calculation. A specific example of each planar optical diffraction element 41ai is similar to the specific example of each planar optical diffraction element 11ai (i=1, 2, 3, 4) included in the optical calculation device 1 according to the first embodiment, and therefore a description thereof will be omitted here.

[0051] In this embodiment, the first planar optical diffraction element 41a1 and the second planar optical diffraction element 41a2 are arranged in a straight line on the optical path of the signal light input to the optical processing device 4. Therefore, the signal light input to the optical processing device 4 passes through the first planar optical diffraction element 41a1 and the second planar optical diffraction element 41a2 in this order. A mirror 43 is arranged on the optical path of the signal light that has passed through the second planar optical diffraction element 41a2. The mirror 43 can orient its reflective surface in a first direction and can orient its reflective surface in a second direction.

[0052] When the reflecting surface of the mirror 43 faces the first direction, the third planar light diffraction element 41a3 and the fourth planar light diffraction element 41a4 are arranged in a straight line on the optical path of the signal light reflected by the mirror 43. Therefore, the signal light reflected by the mirror 43 passes through the third planar light diffraction element 41a3 and the fourth planar light diffraction element 41a4 in this order. Therefore, in this case, in the optical calculation device 4, the first optical calculation by the first planar light diffraction element 41a1, the second optical calculation by the second planar light diffraction element 41a2, the third optical calculation by the third planar light diffraction element 41a3, and the fourth optical calculation by the fourth planar light diffraction element 41a4 are executed in this order.

[0053] When the reflecting surface of the mirror 43 faces the second direction, the fifth planar light diffraction element 41a5 and the sixth planar light diffraction element 41a6 are arranged in a straight line on the optical path of the signal light reflected by the mirror 43. Therefore, the signal light reflected by the mirror 43 passes through the fifth planar light diffraction element 41a5 and the sixth planar light diffraction element 41a6 in this order. Therefore, in this case, in the optical calculation device 4, the first optical calculation by the first planar light diffraction element 41a1, the second optical calculation by the second planar light diffraction element 41a2, the fifth optical calculation by the fifth planar light diffraction element 41a5, and the sixth optical calculation by the sixth planar light diffraction element 41a6 are executed in this order.

[0054] (Effect of optical computing device) As described above, the optical calculation device 4 includes the mirror 43, which is an optical element that guides the optical path of the signal light to the first optical path (optical path A in FIG. 5) or the second optical path (optical path B in FIG. 5), and functions as an optical element in which the optical path along which the signal light is guided is variable. The optical diffraction element group 41 includes planar optical diffraction elements 41a3 and 41a4 provided on the first optical path, and planar optical diffraction elements 41a5 and 41a6 provided on the second optical path.

[0055] Therefore, the optical arithmetic device 4 allows the user to select either the optical path A or B. Therefore, the optical arithmetic device 4 allows the user to execute any one of a plurality of optical arithmetic operations (two in this embodiment), and allows the user to select which optical arithmetic operation to execute.

[0056] Fifth embodiment (Configuration of Optical Computing Unit) The configuration of an optical arithmetic unit 5 according to a fifth embodiment of the present invention will be described with reference to Fig. 6. Fig. 6 is a perspective view showing the configuration of the optical arithmetic unit 5.

[0057] The optical calculation device 5 includes an optical diffraction element group 51, a substrate 52, and a mirror 53. The optical diffraction element group 51 is composed of a plurality of (six in this embodiment) planar optical diffraction elements 51a1-51a6. In this embodiment, the planar optical diffraction elements 51a1-51a6 are made of resin and have a plate-like shape with a square shape in a plan view. In this embodiment, the substrate 52 is made of glass and has a plate-like shape with a rectangular shape in a plan view.

[0058] The end faces of the planar optical diffraction elements 51a1 to 51a6 are fixed directly to the principal surface of the substrate 52 so that the entrance surface and exit surface of each of the planar optical diffraction elements 51a1 to 51a6 intersect with the principal surface of the substrate 52 (orthogonal to each other in this embodiment).

[0059] Each planar optical diffraction element 51ai (i=1, 2, ..., 6) is composed of a plurality of microcells whose thickness or refractive index is set independently of each other. When signal light is incident on the optical calculation device 5, the signal light having different phases transmitted through each microcell interferes with each other to perform a predetermined optical calculation. A specific example of each planar optical diffraction element 51ai is similar to the specific example of each planar optical diffraction element 11ai (i=1, 2, 3, 4) included in the optical calculation device 1 according to the first embodiment, and therefore a description thereof will be omitted here.

[0060] In this embodiment, the first planar optical diffraction element 51a1 and the second planar optical diffraction element 51a2 are arranged in a straight line on the optical path of the signal light input to the optical processing device 5. Therefore, the signal light input to the optical processing device 5 passes through the first planar optical diffraction element 51a1 and the second planar optical diffraction element 51a2 in this order. A mirror 53 is arranged on the optical path of the signal light that has passed through the second planar optical diffraction element 51a2. The mirror 53 can be (1) fixed to the substrate 52 so that its reflecting surface faces the first direction as shown by the solid line in FIG. 6, or (2) fixed to the substrate 52 so that its reflecting surface faces the second direction as shown by the dotted line in FIG. 6.

[0061] When the mirror 53 is fixed to the substrate 52 so that the reflecting surface faces the first direction, the third planar light diffraction element 51a3 and the fourth planar light diffraction element 51a4 are arranged in a straight line on the optical path of the signal light reflected by the mirror 53. Therefore, the signal light reflected by the mirror 53 passes through the third planar light diffraction element 51a3 and the fourth planar light diffraction element 51a4 in this order. Therefore, in this case, in the optical calculation device 5, the first optical calculation by the first planar light diffraction element 51a1, the second optical calculation by the second planar light diffraction element 51a2, the third optical calculation by the third planar light diffraction element 51a3, and the fourth optical calculation by the fourth planar light diffraction element 51a4 are executed in this order.

[0062] When the mirror 53 is fixed to the substrate 52 so that the reflecting surface faces the second direction, the fifth planar light diffraction element 51a5 and the sixth planar light diffraction element 51a6 are arranged in a straight line on the optical path of the signal light reflected by the mirror 53. Therefore, the signal light reflected by the mirror 53 passes through the fifth planar light diffraction element 51a5 and the sixth planar light diffraction element 51a6 in this order. Therefore, in this case, in the optical calculation device 5, the first optical calculation by the first planar light diffraction element 51a1, the second optical calculation by the second planar light diffraction element 51a2, the fifth optical calculation by the fifth planar light diffraction element 51a5, and the sixth optical calculation by the sixth planar light diffraction element 51a6 are executed in this order.

[0063] (Effect of optical computing device) As described above, the optical calculation device 5 includes the mirror 53, which is an optical element that guides the optical path of the signal light to the first optical path (optical path A in FIG. 6) or the second optical path (optical path B in FIG. 6) and functions as an optical element that does not change the optical path through which the signal light is guided. The optical diffraction element group 51 includes planar optical diffraction elements 51a3 and 51a4 provided on the first optical path, and planar optical diffraction elements 51a5 and 51a6 provided on the second optical path.

[0064] Therefore, the optical arithmetic device 5 allows the manufacturer to select either the optical path A or B. Therefore, the optical arithmetic device 5 allows the manufacturer to select either one of a plurality of optical arithmetic operations (two in this embodiment) to be executed, and allows the manufacturer to select which optical arithmetic operation to execute.

[0065] Sixth embodiment (Configuration of Optical Computing Unit) The configuration of an optical arithmetic device 6 according to a sixth embodiment of the present invention will be described with reference to Fig. 7. Fig. 7 is a perspective view showing the configuration of the optical arithmetic device 6.

[0066] The optical calculation device 6 includes an optical diffraction element group 61 and a substrate 62. The optical diffraction element group 61 is composed of a plurality of (two in this embodiment) planar optical diffraction elements 61a1-61a2. In this embodiment, the planar optical diffraction elements 61a1-61a2 are made of resin and have a plate-like shape in a square shape in a plan view. In this embodiment, the substrate 62 is made of glass and has a plate-like shape in a square shape in a plan view.

[0067] The first planar optical diffraction element 61a1 is fixed to the substrate 62 such that its exit surface is in surface contact with one of the main surfaces of the substrate 62. On the other hand, the second planar optical diffraction element 61a2 is fixed to the substrate 62 such that its entrance surface is in surface contact with the other main surface of the substrate 62.

[0068] Each planar light diffraction element 61ai (i=1, 2) is composed of a plurality of microcells whose thickness or refractive index is set independently of each other. When the microcells are composed of pillars, the pillars of the first planar light diffraction element 61a1 are provided, for example, on the incident surface side of the first planar light diffraction element 61a1, and the pillars of the second planar light diffraction element 61a2 are provided, for example, on the exit surface side of the second planar light diffraction element 61a2. When signal light is incident on the optical calculation device 6, the signal lights having different phases transmitted through each microcell interfere with each other, thereby performing a predetermined optical calculation. A specific example of each planar light diffraction element 61ai is similar to the specific example of each planar light diffraction element 11ai (i=1, 2, 3, 4) included in the optical calculation device 1 according to the first embodiment, and therefore a description thereof will be omitted here.

[0069] In this embodiment, the first planar optical diffraction element 61a1 and the second planar optical diffraction element 61a2 are arranged in a straight line on the optical path of the signal light input to the optical processing device 6. Therefore, the signal light input to the optical processing device 6 passes through the first planar optical diffraction element 61a1 and the second planar optical diffraction element 61a2 in this order. Therefore, in the optical processing device 6, the first optical calculation by the first planar optical diffraction element 61a1 and the second optical calculation by the second planar optical diffraction element 61a2 are executed in this order.

[0070] (Effect of optical computing device) As described above, the optical calculation device 6 includes the substrate 62 and the optical diffraction element group 61 including a plurality of planar optical diffraction elements 61a1-61a2. Each planar optical diffraction element 61ai belonging to the optical diffraction element group 61 is composed of a plurality of microcells whose thickness or refractive index is set independently of each other. The first planar optical diffraction element 61a1 is fixed to the substrate 62 such that its exit surface is in surface contact with one of the main surfaces of the substrate 62. The second planar optical diffraction element 61a2 is fixed to the substrate 62 such that its entrance surface is in surface contact with the other main surface of the substrate 62.

[0071] For this reason, in the optical calculation device 6, the entire exit surface or entrance surface of each planar optical diffraction element 61ai is fixed to the substrate 62. Therefore, compared to the case where the entire outer circumference of each planar optical diffraction element 61ai is fixed to the inner surface of a cylindrical holder by utilizing the technology described in Patent Document 1, distortion or stress caused by changes in environmental temperature is less likely to occur in each planar optical diffraction element 61ai. Therefore, it is possible to realize an optical calculation device 6 that can easily maintain its calculation function even if the environmental temperature changes.

[0072] (Modification of the optical computing device) It is also possible to realize an optical arithmetic unit including a plurality of optical arithmetic units 6. Fig. 8 is a perspective view showing the structure of such an optical arithmetic unit 6A.

[0073] The optical arithmetic device 6A has four optical arithmetic devices 6 arranged on a substrate 63. In the optical arithmetic device 6A, the end face of the substrate 62 of each optical arithmetic device 6 is directly fixed to the main surface of the substrate 63 so that the main surface of the substrate 62 intersects with the main surface of the substrate 63 (orthogonal in this embodiment). As described above, it becomes easy to maintain the arithmetic function of each optical arithmetic device 6 even if the environmental temperature changes. As a result, it becomes easy to maintain the arithmetic function of the optical arithmetic device 6A, which is an assembly of optical arithmetic devices 6, even if the environmental temperature changes.

[0074] 〔summary〕 In order to solve the above problems, an optical computing device according to a first aspect of the present invention comprises a substrate, an optical diffraction element group including a plurality of planar optical diffraction elements, a cover facing the substrate and supported so as not to come into contact with each of the planar optical diffraction elements belonging to the optical diffraction element group, and side walls surrounding the optical diffraction element group on all sides, the side walls having one end fixed to an upper surface of the substrate and the other end fixed to a lower surface of the cover, and each of the planar optical diffraction elements belonging to the optical diffraction element group is composed of a plurality of microcells whose thicknesses or refractive indices are set independently of each other, and is fixed to the substrate.

[0075] In addition, in an optical computing device according to a second aspect of the present invention, in addition to the configuration of the optical computing device according to the first aspect described above, a liquid or gas is sealed in the space surrounded by the substrate, the cover, and the side chamber.

[0076] In addition, in an optical computing device according to a second aspect of the present invention, in addition to the configuration of the optical computing device according to the second aspect described above, the liquid is matching oil.

[0077] In addition, in an optical computing device according to a second aspect of the present invention, in addition to the configuration of the optical computing device according to the second aspect described above, the gas is nitrogen gas.

[0078] Furthermore, in an optical computing device according to a fifth aspect of the present invention, in addition to the configuration of the optical computing device according to any one of the first to fourth aspects described above, each planar optical diffraction element belonging to the optical diffraction element group is fixed to the substrate so that its entrance surface and exit surface intersect with the main surface of the substrate.

[0079] Furthermore, in an optical computing device according to a sixth aspect of the present invention, in addition to the configuration of the optical computing device according to any one of the first to fourth aspects described above, an optical element is further provided which folds the optical path of the signal light within a plane intersecting with the main surface of the substrate, and the optical diffraction element group includes a planar optical diffraction element provided on one of the optical paths before and after the folding and fixed directly to the substrate, and a planar optical diffraction element provided on the other of the optical paths before and after the folding and indirectly fixed to the substrate via the planar optical diffraction element directly fixed to the substrate.

[0080] Furthermore, in an optical computing device according to a seventh aspect of the present invention, in addition to the configuration of the optical computing device according to any one of the first to fourth aspects described above, a configuration is adopted in which the optical diffraction element group includes a planar optical diffraction element provided on a first optical path, and a planar optical diffraction element provided on a second optical path different from the first optical path.

[0081] In addition, an optical computing device according to an eighth aspect of the present invention has a configuration in which, in addition to the configuration of the optical computing device according to the seventh aspect described above, it further includes an optical element that branches the optical path of the signal light into the first optical path and the second optical path.

[0082] Furthermore, in an optical computing device according to a ninth aspect of the present invention, in addition to the configuration of the optical computing device according to the seventh aspect described above, a configuration is adopted in which an optical element that guides signal light to the first optical path or the second optical path, and the optical path along which the signal light is guided, is further provided with an optical element that is variable.

[0083] Furthermore, in an optical computing device according to a tenth aspect of the present invention, in addition to the configuration of the optical computing device according to the seventh aspect described above, a configuration is adopted in which the optical computing device further includes an optical element that guides signal light to the first optical path or the second optical path, and the optical path along which the signal light is guided is invariant.

[0084] An optical computing device according to an eleventh aspect of the present invention has the same configuration as the optical computing device according to any one of the first to tenth aspects described above, and further has a configuration in which the optical diffraction element group includes a planar optical diffraction element having a plurality of pillars formed on both sides, the heights of which are set independently of each other.

[0085] In order to solve the above problem, a manufacturing method for an optical computing device according to a 12th aspect of the present invention is a manufacturing method for an optical computing device according to any one of the first to 11th aspects described above, and includes a step of collectively forming each planar optical diffraction element belonging to the optical diffraction element group.

[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 the above-described embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0087] 1,2,3,4,5,6,6A optical operation device 11, 21, 31, 41, 51, 61 Optical diffraction element group 11ai,21ai,31ai,41ai,51ai,61ai Planar optical diffraction element 12,22,32,42,52,62,63 Board 23,33 Prism (optical element) 34, 43, 53 Mirror (optical element) 15 Cover

Claims

1. a substrate; an optical diffraction element group including a plurality of planar optical diffraction elements fixed to the substrate; a cover facing the substrate and supported so as not to come into contact with each of the planar optical diffraction elements belonging to the optical diffraction element group; and side walls surrounding the optical diffraction element group from all sides, the side walls having one end fixed to an upper surface of the substrate and the other end fixed to a lower surface of the cover, Each planar optical diffraction element belonging to the optical diffraction element group is composed of a plurality of microcells each having a thickness or a refractive index set independently of one another, and is fixed to the substrate. An optical computing device comprising:

2. A liquid or a gas is sealed in a space surrounded by the substrate, the cover, and the side wall.

2. The optical computing device according to claim 1 .

3. The liquid is a matching oil.

3. The optical computing device according to claim 2.

4. The gas is nitrogen gas.

3. The optical computing device according to claim 2.

5. Each planar optical diffraction element belonging to the optical diffraction element group is fixed to the substrate such that an entrance surface and an exit surface thereof intersect with a main surface of the substrate.

5. The optical computing device according to claim 1, wherein the optical computing device comprises:

6. The optical element further includes an optical element that folds an optical path of the signal light within a plane intersecting with the main surface of the substrate, The optical diffraction element group includes a planar optical diffraction element provided on one of the optical paths before and after the folding and directly fixed to the substrate, and a planar optical diffraction element provided on the other optical path before and after the folding and indirectly fixed to the substrate via the planar optical diffraction element directly fixed to the substrate.

5. The optical computing device according to claim 1, wherein the optical computing device comprises:

7. the optical diffraction element group includes a planar optical diffraction element provided on a first optical path, and a planar optical diffraction element provided on a second optical path different from the first optical path.

5. The optical computing device according to claim 1, wherein the optical computing device comprises:

8. The optical fiber further includes an optical element that splits an optical path of the signal light into the first optical path and the second optical path.

8. The optical computing device according to claim 7.

9. The optical element further includes an optical element that guides a signal light to the first optical path or the second optical path, the optical path through which the signal light is guided being variable.

8. The optical computing device according to claim 7.

10. The optical element further includes an optical element that guides the signal light to the first optical path or the second optical path, the optical path along which the signal light is guided being invariable.

8. The optical computing device according to claim 7.

11. The optical diffraction element group includes a planar optical diffraction element having a plurality of pillars formed on both sides, the heights of which are set independently of each other.

11. The optical computing device according to claim 1, wherein the optical computing device comprises:

12. A method for manufacturing an optical arithmetic device according to any one of claims 1 to 11, comprising the steps of: A method for manufacturing an optical computing device, comprising the step of forming all of the planar optical diffraction elements belonging to the group of optical diffraction elements at once.

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