Optical computation device

Abstract

The present invention realizes an optical computation device that can perform high-speed, high-efficiency optical computation. An optical computation device (1) comprises an optical diffraction element group (11) and a lens group (12). Each lens (12a1–12am) of the lens group (12) is positioned such that a point on a specific plane (S0) or a point at infinity and a point on a plane of incidence (S1) for a first optical diffraction element (11a) are substantially conjugate to the lens group (12).

Description

optical calculation device

[0001] The present invention relates to an optical arithmetic device that performs optical arithmetic using an optical diffraction element.

[0002] Optical diffraction elements are known that have multiple cells and are designed to optically perform a predetermined operation by causing signal light transmitted through each cell to interfere with each other. Optical operations using such optical diffraction elements have the advantage of being faster and requiring less power than electrical operations using a processor. Furthermore, by sequentially applying the signal light to two or more optical diffraction elements arranged side by side, multi-stage optical operations (two or more stages of optical operations) can be realized.

[0003] Patent Literature 1 discloses an optical neural network having an input layer, an intermediate layer, and an output layer. The optical diffraction element described above can be used, for example, as the intermediate layer of such an optical neural network.

[0004] U.S. Patent No. 7,847,225

[0005] However, in conventional optical computing devices, optical computation is performed on the visual information of an object by inputting light from a display displaying an image including the object as a subject to a group of optical diffraction elements. Therefore, in order to form an image including the object as a subject, it is necessary to convert the optical signal into an electrical signal using an image sensor. Furthermore, in order to display the image including the object as a subject, it is necessary to convert the electrical signal into an optical signal using a display. Therefore, conventional optical computing devices have room for improvement in both speed and efficiency.

[0006] One aspect of the present invention has been made in view of the above problems, and an object of the present invention is to realize an optical arithmetic device capable of performing optical arithmetic at high speed and with high efficiency.

[0007] An optical computing device according to one aspect of the present invention comprises: a lens group consisting of at least one lens, the lens group being arranged on a specific plane and acting on light from each point on an object other than a display; and an optical diffraction element group consisting of at least one optical diffraction element, the optical diffraction element closest to the lens group being designated as a first optical diffraction element, and each lens constituting the lens group being arranged so that a point on the specific plane or a point at infinity and the incident surface of the first optical diffraction element are substantially conjugate with respect to the lens group.

[0008] According to an aspect of the present invention, an optical computing device can perform optical computations at high speed and with high efficiency, and can easily calculate changes in the complex electric field information of light that occur during the propagation of light from an object to an optical diffraction element group.

[0009] 6A and 6B are side views schematically showing the configuration of an optical arithmetic device according to one embodiment of the present invention; FIG. 6A is a plan view showing a specific example of an optical diffraction element included in the optical arithmetic device shown in FIGS. 1 and 2; FIG. 6B is a perspective view showing an enlarged portion of the optical diffraction element shown in FIG. 6A; FIG. 6B is a perspective view showing a schematic diagram of a beam shape of light output from an optical diffraction element group in the optical arithmetic device shown in FIGS. 1 and 2; FIG. 6C is a perspective view showing a schematic diagram of a light flux shape of light output from an optical diffraction element group in the optical arithmetic device shown in FIGS. 1 and 2; FIG. 6D is a side view schematically showing a first modified example of the optical arithmetic device shown in FIG. 6A; FIG. 6A is a side view showing an example of the arrangement of relay lenses constituting the lens group in the optical arithmetic device shown in FIG. 6A when the lens group is a magnification system; FIG. 6B is a side view showing an example of the arrangement of relay lenses constituting the lens group in the optical arithmetic device shown in FIG. 6A when the lens group is a reduction system; and FIG. 6D is a side view schematically showing a second modified example of the optical arithmetic device shown in FIG. 6A. 1A is a side view showing an example of the arrangement of relay lenses constituting the lens group of the optical processing device shown in FIG. 7 when the lens group is a magnification system. FIG. 1B is a side view showing an example of the arrangement of relay lenses constituting the lens group of the optical processing device shown in FIG. 7 when the lens group is a reduction system. FIG. 1C is a perspective view schematically showing a first application example of the optical processing device shown in FIGS. 1, 2, 6, and 8. FIG. 1D is a perspective view schematically showing a second application example of the optical processing device shown in FIGS. 1, 2, 6, and 8. FIG. 1E is a perspective view schematically showing a third application example of the optical processing device shown in FIGS. 1, 2, 6, and 8. FIG. 1F is a perspective view schematically showing a fourth application example of the optical processing device shown in FIGS. 1, 2, 6, and 8. FIG. 1G is a perspective view schematically showing a fifth application example of the optical processing device shown in FIGS. 1, 2, 6, and 8. FIG. 1H is a perspective view schematically showing a sixth application example of the optical processing device shown in FIGS. 1, 2, 6, and 8.

[0010] [Configuration of Optical Arithmetic Device] The configuration of optical arithmetic devices 1A and 1B according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a side view schematically showing the configuration of optical arithmetic device 1A, and Fig. 2 is a side view schematically showing the configuration of optical arithmetic device 1B.

[0011] The optical calculation devices 1A and 1B are devices for performing optical calculations on light from an object other than a display arranged on a specific plane S0. The light from the object that is the subject of the optical calculations may be transmitted light that has passed through the object, reflected light that has been reflected by the object, or scattered light that has been scattered by the object. As shown in Figures 1 and 2, the optical calculation devices 1A and 1B include an optical diffraction element group 11 and a lens group 12.

[0012] The optical diffraction element group 11 is a collection of n optical diffraction elements 11a1 to 11an, where n is any natural number equal to or greater than 1. Each optical diffraction element 11ai is an element having an optical calculation function, that is, a function of converting the two-dimensional intensity distribution of input light in accordance with a predetermined conversion rule. Here, i is a natural number equal to or greater than 1 and equal to or less than n. Specific examples of each optical diffraction element 11ai will be described later with reference to FIG. 3.

[0013] The n optical diffraction elements 11a1 to 11an constituting the optical diffraction element group 11 are arranged in a straight line on the optical path of light from an object arranged on the plane S0 that has passed through the lens group 12 (hereinafter simply referred to as "light that has passed through the lens group 12"). The light that has passed through the lens group 12 passes through the optical diffraction element 11a1, the optical diffraction element 11a2, ..., and the optical diffraction element 11an in this order. Therefore, the optical diffraction element group 11 performs an optical operation on the light that has passed through the lens group 12 by combining the optical operation by the optical diffraction element 11a1, the optical operation by the optical diffraction element 11a2, ..., and the optical operation by the optical diffraction element 11an in this order.

[0014] Hereinafter, of the n optical diffraction elements 11a1 to 11an constituting the optical diffraction element group 11, the optical diffraction element 11a1 closest to the lens group 12 will be referred to as the "first optical diffraction element," and a plane including the incident surface of the first optical diffraction element 11a1 will be referred to as plane S1. Furthermore, of the optical diffraction elements 11a1 to 11an constituting the optical diffraction element group 11, the optical diffraction element 11an farthest from the lens group 12 will also be referred to as the "nth optical diffraction element," and a plane including the exit surface of the nth optical diffraction element 11an will be referred to as plane S2.

[0015] The lens group 12 is a collection of m lenses 12a1 to 12am, where m is any natural number equal to or greater than 1. The lens group 12 acts on light from an object that is the subject of optical computation, and the light that has been acted upon by the lens group 12 (in this embodiment, light that has passed through the lens group 12) is input to the optical diffraction element group 11. The n lenses 12a1 to 12am that constitute the lens group 12 are arranged such that (1) a point on the plane S0 and a point on the plane S1 are conjugate with respect to the lens group 12 (hereinafter also referred to as the "first condition"), or (2) a point at infinity and a point on the plane S1 are conjugate with respect to the lens group 12 (hereinafter also referred to as the "second condition").

[0016] When the m lenses 12a1 to 12am constituting the lens group 12 are arranged so as to satisfy the first condition described above, the lens group 12 exhibits the function of converging light from each point on the plane S0 that passes through the lens group 12 to each point on the plane S1 (hereinafter also referred to as the "first function"). The lens group 12 of the optical computing device 1A shown in Figure 1 is configured as the lens group 12 having the first function described above, by a single imaging lens 12a1 that is arranged so as to satisfy the first condition described above. Figure 1 shows how light from the intersection P of the optical axis of the imaging lens 12a1 and the plane S0 is converged at the intersection Q of the optical axis of the imaging lens 12a1 and the plane S1.

[0017] On the other hand, when the m lenses 12a1 to 12am constituting the lens group 12 are arranged so as to satisfy the second condition described above, the lens group 12 exhibits the function of focusing light from a point at infinity that passes through the lens group 12 to each point on the plane S1 (hereinafter also referred to as the "second function"). The lens group 12 of the optical computing device 1B shown in Figure 2 is configured as the lens group 12 having the second function described above, by using a single Fourier lens 12a1 that is arranged so as to satisfy the second condition described above. Figure 2 shows how light from a point at infinity that travels parallel to the optical axis of the Fourier lens 12a1 is focused at the intersection Q between the optical axis of the Fourier lens 12a1 and the plane S1.

[0018] In conventional optical computing devices, light from a display showing an image of an object as a subject is input to an optical diffraction element group to perform optical computation on the visual information of the object.In contrast, in the optical computing devices 1A and 1B according to the present embodiment, light from the object itself is input to the optical diffraction element group 11 to perform optical computation on the visual information of the object.

[0019] Therefore, in the optical arithmetic devices 1A and 1B according to the present embodiment, it is not necessary to convert optical signals into electrical signals in order to form an image that includes the object as a subject. Furthermore, it is not necessary to convert electrical signals into optical signals in order to display an image that includes the object as a subject. Therefore, the optical arithmetic devices 1A and 1B according to the present embodiment can perform optical arithmetic on the visual information of an object more quickly and efficiently than conventional optical arithmetic devices.

[0020] Furthermore, when adopting a configuration in which light from an object is input to the optical diffraction element group 11 without passing through the lens group 12, it is necessary to take into account the interference and diffraction of light. Therefore, it is difficult to calculate changes in the complex electric field information (intensity information and phase information) of the light that occur during the propagation of the light from the object to the optical diffraction element group 11. In contrast, in the optical computing devices 1A and 1B according to the present embodiment, light from an object is input to the optical diffraction element group 11 via the lens group 12 that satisfies the first or second condition described above. When such a configuration is adopted, it is easy to calculate changes in the complex electric field information of the light that occur during the propagation of the light from the object to the optical diffraction element group 11. This is because, if the first condition is satisfied, intensity information is preserved during the propagation of the light from the object to the optical diffraction element group 11, and phase information can also be calculated by ray tracing. Furthermore, if the second condition is satisfied, the complex electric field information of the light is converted into a spatial frequency during the propagation of the light from the object to the optical diffraction element group 11.

[0021] Therefore, in the optical computing devices 1A and 1B according to the present embodiment, when designing each optical diffraction element 11ai, it is easy to take into account changes in complex electric field information that occur during the propagation of light from an object to the first optical diffraction element 11a1. As a result, it is easy to improve the accuracy of the optical computing device. In particular, when designing each optical diffraction element 11ai using machine learning, as described below, it is easy to prepare a training dataset and ensure the accuracy of the trained model.

[0022] The optical computing devices 1A and 1B may include a light source that irradiates an object placed on the plane S0 with light from the lens group 12 side, or a light source that irradiates an object placed on the plane S0 with light from the side opposite the lens group 12 side. A light source that irradiates an object with light from the lens group 12 side is effective when light reflected or scattered by the object is made incident on the optical diffraction element group 11 via the lens group 12. On the other hand, a light source that irradiates an object with light from the side opposite the lens group 12 side is effective when light that has passed through the object is made incident on the optical diffraction element group 11 via the lens group 12. As the light source, for example, an LD (Laser Diode) or an LED (Light Emitting Diode) can be used.

[0023] The optical computing devices 1A and 1B may further include an image sensor that converts the signal light output from the optical diffraction element group 11 into an electrical signal. As the image sensor, for example, a two-dimensional image sensor including a plurality of light-receiving cells arranged in a matrix can be used.

[0024] [Specific Example of Optical Diffraction Element] A specific example of the optical diffraction element 11ai constituting the optical diffraction element group 11 will be described with reference to Fig. 3. Fig. 3(a) is a plan view of the optical diffraction element 11ai according to this specific example. Fig. 3(b) is an enlarged perspective view of a portion of the optical diffraction element 11ai according to this specific example (the portion surrounded by a dotted line in Fig. 3(a)).

[0025] The optical diffraction element 11ai is composed of a plurality of microcells, each having a thickness or refractive index set independently of the other. When light transmitted through the lens group 12 enters the optical diffraction element 11ai, the light beams diffracted by the microcells with different phases as they pass through the microcells interfere with each other, thereby performing a predetermined optical calculation (conversion of the two-dimensional intensity distribution according to a predetermined conversion rule).

[0026] In this specification, the term "microcell" refers to a cell having a cell size of less than 10 μm, for example. In addition, 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 square, the cell size is the length of one side of the cell. The lower limit of the cell size is, for example, 1 nm.

[0027] 3 is composed of 200 × 200 microcells arranged in a matrix. Each microcell has a square shape of 500 nm × 500 nm in plan view, and the optical diffraction element 11 ai has a square shape of 100 μm × 100 μm in plan view.

[0028] (1) By independently setting the thickness of each microcell for each cell, or (2) by independently setting the refractive index of each microcell for each cell, the phase shift amount of light passing through each microcell can be independently set for each cell. In this embodiment, method (1), which can be realized by nanoimprinting, is adopted. In this case, as shown in FIG. 3B, each microcell is formed by a rectangular pillar having a square base with each side length equal to the cell size. In addition, in this case, the phase shift amount of light passing through each microcell is determined by the height of the pillars constituting the microcell. That is, the phase shift amount of light passing through a microcell formed by tall pillars is large, and the phase shift amount of light passing through a microcell formed by short pillars is small.

[0029] The thickness or refractive index of each microcell of each optical diffraction element 11ai can be set using, for example, machine learning. A model used in this machine learning can be, for example, a model that takes a two-dimensional intensity distribution of light from an object on a plane S1 as an input and a two-dimensional intensity distribution of light from the optical diffraction element group 11 on a plane S2 as an output, and that includes the thickness or refractive index of each microcell of each optical diffraction element 11ai as a parameter.

[0030] [Supplementary Notes on the First and Second Conditions] The arrangement of the lenses 12a1 to 12am constituting the lens group 12 is preferably set so as to satisfy the first condition described above, i.e., so that a point on the plane S0 and a point on the plane S1 are conjugate with respect to the lens group 12. However, the present invention is not limited to this. In other words, it is sufficient that the arrangement of the lenses 12a1 to 12am constituting the lens group 12 is set so that a point on the plane S0 and a point on the plane S1 are substantially conjugate with respect to the lens group 12, and they do not need to be set so that they are strictly conjugate. As described above, the plane S0 is the plane on which an object is arranged, and the plane S1 is the plane on which the incident surface of the first optical diffraction element 11a1 is arranged.

[0031] Here, the fact that a point on plane S0 and a point on plane S1 are strictly conjugate with respect to the lens group 12 is equivalent to the beam waist BW of light from a point on plane S0 that has passed through the lens group 12 being formed on plane S1, as shown in FIG. 3 . On the other hand, the fact that a point on plane S0 and a point on plane S1 are substantially conjugate with respect to the lens group 12 is equivalent to the distance D between the beam waist BW and plane S1 being sufficiently small compared to the front focal length f of the lens group 12. As an example, the fact that a point on plane S0 and a point on plane S1 are substantially conjugate with respect to the lens group 12 is equivalent to the distance D between the beam waist BW and plane S1 being D2 × f / D1 or less. Here, D1 is the beam diameter at the principal surface of the lens 12a1 closest to the optical diffraction element group 11, and D2 is the diameter of the beam waist BW, i.e., the beam diameter at the front focal position of the lens group 12. In this case, the beam diameter on the plane S1 is equal to or less than twice the diameter of the beam waist BW described above (which is usually approximately the same as the cell size of the first optical diffraction element 11a1). Therefore, the computational load in setting the thickness or refractive index of each microcell of each optical diffraction element 11ai using machine learning can be kept sufficiently small.

[0032] Furthermore, it is preferable that the arrangement of the lenses 12a1 to 12am that constitute the lens group 12 is set so as to satisfy the second condition described above, that is, so that the point at infinity and a point on the plane S1 are conjugate with respect to the lens group 12. However, the present invention is not limited to this. That is, it is sufficient that the arrangement of the lenses 12a1 to 12am that constitute the lens group 12 is set so that the point at infinity and a point on the plane S1 are substantially conjugate with respect to the lens group 12, and it is not necessary that they are set so that they are strictly conjugate. As described above, the plane S0 is the plane on which an object is placed.

[0033] Here, the fact that the point at infinity and a point on the plane S1 are strictly conjugate with respect to the lens group 12 is equivalent to the beam waist BW of light from the point at infinity that has passed through the lens group 12 being formed on the plane S1, as shown in FIG. 3 . On the other hand, the fact that the point at infinity and a point on the plane S1 are substantially conjugate with respect to the lens group 12 means that the distance D between the beam waist BW and the plane S1 is sufficiently small compared to the front focal length f of the lens group 12. As an example, the fact that the point at infinity and a point on the plane S1 are substantially conjugate with respect to the lens group 12 is equivalent to the distance D between the beam waist BW and the plane S1 being D2 × f / D1 or less. In this case, the beam diameter on the plane S1 is less than twice the diameter of the beam waist BW (usually approximately the same as the cell size of the first optical diffraction element 11a1). Therefore, the computational load involved in setting the thickness or refractive index of each microcell of each optical diffraction element 11ai using machine learning can be kept sufficiently low.

[0034] [Additional Information Regarding Aperture] The optical computing devices 1A and 1B according to the present embodiment preferably further include an aperture for limiting the tangent tan θ of the angle of incidence θ of light transmitted through the lens group 12 to λ / (2d) or less. Here, λ is the wavelength of light transmitted through the lens group 12, and d is the cell size of the microcells constituting the first optical diffraction element 11a1. The first optical diffraction element 11a1 can correctly execute a predetermined optical computation when the tangent tan θ of the angle of incidence θ of light transmitted through the lens group 12 to λ / (2d) or less.

[0035] In order to limit the tangent tan θ of the angle of incidence θ when light transmitted through the lens group 12 is incident on the first optical diffraction element 11a1 to λ / (2d) or less, for example, as shown in Fig. 5, the beam diameter on the principal surface of the lens 12a1 closest to the optical diffraction element group 11 may be limited to λ × f / d or less, where f is the rear focal length of the lens group 12. Therefore, when an aperture is provided inside or near the lens 12a1 as shown in Fig. 4, the aperture diameter may be set to λ × f / d or less.

[0036] [Optical arithmetic device variation 1] A first variation of the optical arithmetic device 1A (hereinafter referred to as "optical arithmetic device 1C") will be described with reference to Figures 6 and 7. Figure 6 is a side view schematically showing the configuration of the optical arithmetic device 1C. Figure 7 is a side view schematically showing the configuration of a portion of the optical arithmetic device 1C.

[0037] Like the optical processing device 1A, the optical processing device 1C includes an optical diffraction element group 11 and a lens group 12. The optical diffraction element group 11 of the optical processing device 1C is configured similarly to the optical diffraction element group 11 of the optical processing device 1A. While the lens group 12 of the optical processing device 1A is a 2f system consisting of one imaging lens 12a1, the lens group 12 of the optical processing device 1C is a 4f system consisting of two relay lenses 12a1 and 12a2.

[0038] In the optical computing device 1C as well, the two relay lenses 12a1 and 12a2 constituting the lens group 12 are arranged so as to satisfy the first condition described above, i.e., so that a point on the plane S0 and a point on the plane S1 are conjugate with respect to the lens group 12. Therefore, the lens group 12 exhibits the function of focusing light from each point on the plane S0 that passes through the lens group 12 onto each point on the plane S1.

[0039] In the optical processing device 1C, by making the focal length f1 of the relay lens 12a1 and the focal length f2 of the relay lens 12a2 different, it is possible to realize both a magnification system and a reduction system.

[0040] Here, the term "magnifying system" refers to a lens system in which the size of the image of an object formed on plane S1 is larger than the size of the object itself. For example, as shown in FIG. 7A, a magnifying system can be realized by making the focal length f1 of the relay lens 12a1 on the optical diffraction element group 11 side longer than the focal length f2 of the relay lens 12a2 on the object side. In this case, the magnification f1 / f2 of the lens group 12 is not particularly limited, but is preferably, for example, 30 times or less. This allows the overall length of the lens group 12 to be kept short.

[0041] A reduction system refers to a lens system in which the size of the image of an object formed on plane S1 is smaller than the size of the object itself. A reduction system can be realized, for example, by shortening the focal length f1 of relay lens 12a1 on the optical diffraction element group 11 side to be shorter than the focal length f2 of relay lens 12a2 on the object side, as shown in FIG. 7B. In this case, the magnification f1 / f2 of lens group 12 is not particularly limited, but is preferably 1 / 30 or greater, for example. This allows the overall length of lens group 12 to be kept short.

[0042] [Optical arithmetic device variation 2] A second variation of the optical arithmetic device 1A (hereinafter referred to as "optical arithmetic device 1D") will be described with reference to Figures 8 and 9. Figure 8 is a side view schematically showing the configuration of the optical arithmetic device 1D. Figure 9 is a side view schematically showing the configuration of a portion of the optical arithmetic device 1D.

[0043] Like the optical processing device 1A, the optical processing device 1D includes an optical diffraction element group 11 and a lens group 12. The optical diffraction element group 11 of the optical processing device 1D is configured similarly to the optical diffraction element group 11 of the optical processing device 1A. While the lens group 12 of the optical processing device 1A is a 2f system consisting of one imaging lens 12a1, the lens group 12 of the optical processing device 1D is an 8f system consisting of four relay lenses 12a1 and 12a2.

[0044] In the optical computing device 1D as well, the four relay lenses 12a1 to 12a4 constituting the lens group 12 are arranged so as to satisfy the first condition described above, that is, so that a point on the plane S0 and a point on the plane S1 are conjugate with respect to the lens group 12. Therefore, the lens group 12 exhibits the function of focusing light from each point on the plane S0 that passes through the lens group 12 onto each point on the plane S1.

[0045] In addition, in the optical computing device 1C, both a magnification system and a reduction system can be realized by differentiating the focal length f1 of the relay lens 12a1 from the focal length f2 of the relay lens 12a2, and / or by differentiating the focal length f3 of the relay lens 12a3 from the focal length f4 of the relay lens 12a4.

[0046] Here, the term "magnifying system" refers to a lens system in which the size of the image of an object formed on plane S1 is larger than the size of the object itself. For example, as shown in FIG. 9A, a magnifying system can be realized by making the focal length f1 of the relay lens 12a1 on the optical diffraction element group 11 side longer than the focal length f2 of the relay lens 12a2 on the object side, and by making the focal length f3 of the relay lens 12a3 on the optical diffraction element group 11 side longer than the focal length f2 of the relay lens 12a4 on the object side. In this case, the magnification f1 / f2×f3 / f4 of the lens group 12 is not particularly limited, but is preferably, for example, 30x or less. This allows the overall length of the lens group 12 to be kept even shorter than when a 4f system is used. However, if it is not necessary to keep the overall length of the lens group 12 that short, it is also possible to increase the magnification to approximately 900x.

[0047] A reduction system refers to a lens system in which the size of the image of an object formed on plane S1 is smaller than the size of the object itself. A reduction system can be realized, for example, as shown in FIG. 9B , by making the focal length f1 of the relay lens 12a1 on the optical diffraction element group 11 side shorter than the focal length f2 of the relay lens 12a2 on the object side, and by making the focal length f3 of the relay lens 12a3 on the optical diffraction element group 11 side shorter than the focal length f2 of the relay lens 12a4 on the object side. In this case, the magnification f1 / f2×f3 / f4 of the lens group 12 is not particularly limited, but is preferably 1 / 30 or greater. This allows the overall length of the lens group 12 to be kept even shorter than when a 4f system is used. However, if it is not necessary to keep the overall length of the lens group 12 that short, it is also possible to reduce the magnification to approximately 1 / 900.

[0048] [Additional Notes on Lenses] In this embodiment, optical lenses (optical glass lenses or optical plastic lenses) are used as the lenses 12a1 to 12am that constitute the lens group 12, but the present invention is not limited to this. That is, some or all of the lenses 12a1 to 12am that constitute the lens group 12 may be replaced with lenses other than optical lenses (optical elements other than optical lenses that have the same function as optical lenses). Examples of lenses other than optical lenses include mirror lenses and metamaterial lenses. A mirror lens achieves an effect on light by reflecting light that is equivalent to the effect on light that an optical lens achieves by transmitting light. Furthermore, a metamaterial lens achieves an effect on light by transmitting or reflecting light that is equivalent to the effect on light that an optical lens achieves by transmitting light.

[0049] [Application Examples of Optical Arithmetic Devices] Application examples of the optical arithmetic devices 1A, 1B, 1C, and 1D (hereinafter simply referred to as "optical arithmetic device 1") will be described with reference to FIGS.

[0050] FIG. 10 is a perspective view showing a first application example of the optical processing device 1. As shown in FIG.

[0051] 10 includes a constraint mechanism 13A in addition to the optical diffraction element group 11 and the lens group 12. The constraint mechanism 13A is configured to constrain an object to be observed within or near a specific plane S0.

[0052] The restraint mechanism 13A is configured with a flow cell whose central axis passes through the plane S0. The object to be observed is contained in the liquid flowing inside the flow cell. The lenses 12a1 to 12am that make up the lens group 12 are arranged to satisfy the first condition described above, that is, so that a point on the central axis of the flow cell and a point on the incident surface of the first optical diffraction element 11a1 are conjugate.

[0053] 10, light that has passed through an object contained in the liquid flowing through the flow cell is incident on the lens group 12. As a result, an image of the object contained in the liquid flowing through the flow cell is formed on the incident surface of the first optical diffraction element 11a1.

[0054] FIG. 11 is a perspective view showing a second application example of the optical processing device 1. In FIG.

[0055] 11 includes a constraint mechanism 13B in addition to the optical diffraction element group 11 and the lens group 12. The constraint mechanism 13B is configured to constrain an object to be observed within or near a specific plane S0.

[0056] The restraining mechanism 13B is composed of a syringe whose central axis passes through the plane S0. The object to be observed is contained in a droplet falling from the syringe. The lenses 12a1 to 12am that make up the lens group 12 are arranged so as to satisfy the first condition described above, that is, so that a point on the central axis of the syringe and the incident surface of the first optical diffraction element 11a1 are conjugate.

[0057] 11, light that has passed through an object contained in a droplet falling from a syringe is incident on the lens group 12. As a result, an image of the object contained in the droplet falling from the syringe is formed on the incident surface of the first optical diffraction element 11a1.

[0058] FIG. 12 is a perspective view showing a third application example of the optical processing device 1. In FIG.

[0059] 12 includes a restraining mechanism 13C in addition to the optical diffraction element group 11 and the lens group 12. The restraining mechanism 13C is configured to restrain a product (an example of an opaque object) to be inspected within or near the plane S0.

[0060] The restraining mechanism 13C is configured with a belt conveyor whose conveying surface is included in a specific plane S0. The product to be inspected is placed on the conveying surface of the belt conveyor. The lenses 12a1 to 12am that make up the lens group 12 are arranged to satisfy the first condition described above, that is, so that a point on the product placed on the conveying surface of the belt conveyor and the incident surface of the first optical diffraction element 11a1 are conjugate.

[0061] 12, light reflected by a product placed on the conveying surface of the belt conveyor is incident on the lens group 12. As a result, an image of the product placed on the conveying surface of the belt conveyor is formed on a plane S1.

[0062] FIG. 13 is a perspective view showing a fourth application example of the optical processing device 1. In FIG.

[0063] 13 includes a restraining mechanism 13D in addition to the optical diffraction element group 11 and the lens group 12. The restraining mechanism 13D is configured to restrain an optical fiber (an example of a transparent object) to be inspected within or near a specific plane S0.

[0064] The restraining mechanism 13D is composed of an unwinding device that unwinds the optical fiber and a winding device that winds the optical fiber. One end of the optical fiber to be inspected is supported by the unwinding device, and the other end is supported by the winding device. The lenses 12a1 to 12am that make up the lens group 12 are arranged to satisfy the first condition described above, that is, so that a point on the central axis of the optical fiber and the incident surface of the first optical diffraction element 11a1 are conjugate.

[0065] 13, light transmitted through an optical fiber supported by an unwinding device and a winding device is incident on a lens group 12. As a result, an image of the optical fiber is formed on a plane S1.

[0066] FIG. 14 is a side view showing a fifth application example of the optical processing device 1. In FIG.

[0067] 14 includes an optical diffraction element group 11 and a lens group 12, as well as a movable body 14A that mounts the optical diffraction element group 11 and the lens group 12. The movable body 14A is configured to move the optical diffraction element group 11 and the lens group 12 to a position that satisfies the first condition described above, that is, a position where a point on the object to be observed and a point on the incident surface of the first optical diffraction element 11a1 are conjugate with each other.

[0068] 14, the object to be observed is a wall surface, and the moving body 14A is a drone 14. In the optical computing device 1 shown in Fig. 14, light reflected from the wall surface is incident on the lens group 12. As a result, an image of the wall surface is formed on a plane S1.

[0069] FIG. 15 is a side view showing a sixth application example of the optical processing device 1. In FIG.

[0070] 15 includes, in addition to the optical diffraction element group 11 and the lens group 12, a movable body 14B on which the optical diffraction element group 11 and the lens group 12 are mounted. The movable body 14B is configured to move the optical diffraction element group 11 and the lens group 12 to a position that satisfies the first condition described above, that is, a position where a point on the object to be inspected and a point on the incident surface of the first optical diffraction element 11a1 are conjugate.

[0071] 15, the object to be observed is a human body, and the moving object 14B is an automobile. In the optical computing device 1 shown in Fig. 15, light reflected from the human body is incident on the lens group 12. As a result, an image of the human body is formed on a plane S1.

[0072] [Summary] The optical computing device of aspect 1 comprises: a lens group consisting of at least one lens, which is arranged on a specific plane and focuses light from each point on an object other than a display; and an optical diffraction element group consisting of at least one optical diffraction element, which has an optical computation function for light from each point on the object, wherein the optical diffraction element closest to the lens group among the optical diffraction elements constituting the optical diffraction element group is designated as a first optical diffraction element, and each lens constituting the lens group is arranged so that a point on the specific plane or a point at infinity and the incident surface of the first optical diffraction element are substantially conjugate with respect to the lens group.

[0073] The optical computing device of aspect 2 is characterized in that, in the optical computing device of aspect 1, the first optical diffraction element is composed of a plurality of microcells whose thicknesses or refractive indices are set independently of each other, and a predetermined optical computation is performed by causing light transmitted through each microcell to interfere with each other.

[0074] The optical computing device of aspect 3 is characterized in that, in the optical computing device of aspect 2, the wavelength of light that passes through the lens group and enters the first optical diffraction element is λ, and the cell size of each microcell that constitutes the first optical diffraction element is d, and the optical computing device of aspect 3 further comprises an aperture for limiting the tangent tanθ of the angle of incidence θ when the light that has passed through the lens group enters the first optical diffraction element to λ / (2d) or less.

[0075] The optical computing device of aspect 4 is an optical computing device of any one of aspects 1 to 3, characterized in that the lens group is composed of a single imaging lens, and the imaging lens is positioned so that a point on the specific plane and a point on the incident surface of the first optical diffraction element are substantially conjugate with respect to the imaging lens.

[0076] An optical computing device according to aspect 5 is an optical computing device according to any one of aspects 1 to 3, characterized in that the lens group is composed of a single Fourier lens, and the Fourier lens is positioned so that a point at infinity and a point on the incident surface of the first optical diffraction element are substantially conjugate with respect to the Fourier lens.

[0077] The optical computing device of aspect 6 is the optical computing device of any one of aspects 1 to 3, characterized in that the lens group is composed of a plurality of relay lenses, and the plurality of relay lenses are arranged so that a point on the specific plane and a point on the incident surface of the first optical diffraction element are substantially conjugate with respect to the lens group.

[0078] The optical computing device of aspect 7 is the optical computing device of aspect 6, characterized in that the multiple relay lenses have a magnifying function that makes the image of the object formed on the incident surface of the first optical diffraction element larger than the object.

[0079] The optical computing device of aspect 8 is characterized in that, in the optical computing device of aspect 7, the multiple relay lenses have a reduction function that makes the image of the object formed on the incident surface of the first optical diffraction element smaller than the object.

[0080] An optical computing device according to Aspect 9 is the optical computing device according to any one of Aspects 1 to 8, further comprising a constraint mechanism that constrains the object to the specific plane.

[0081] The optical computing device of aspect 10 is characterized in that, in the optical computing device of any one of aspects 1 to 8, it further comprises a moving body that moves the optical diffraction element group and the lens group so that the object is positioned on the specific plane.

[0082] [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.

[0083] 1A, 1B, 1C, 1D Optical arithmetic unit 11 Optical diffraction element group 11a1 to 11an Optical diffraction element 12 Lens group 12a1 to 12am Lens 13A, 13B Restraint mechanism 14A, 14B Moving body

Claims

1. An optical computing device comprising: a lens group consisting of at least one lens, the lens group being arranged on a specific plane and acting on light from each point on an object other than a display; and an optical diffraction element group consisting of at least one optical diffraction element, the optical diffraction element closest to the lens group being designated as the first optical diffraction element, and each lens constituting the lens group being arranged so that a point on the specific plane or a point at infinity and the incident surface of the first optical diffraction element are substantially conjugate with the lens group.

2. The optical computing device according to claim 1, characterized in that the first optical diffraction element is composed of multiple microcells whose thicknesses or refractive indices are set independently of each other, and performs a predetermined optical computation by causing the light transmitted through each microcell to interfere with each other.

3. The optical computing device according to claim 2, further comprising an aperture for limiting the tangent tanθ of the angle of incidence θ at which light transmitted through the lens group is incident on the first optical diffraction element to λ / (2d) or less, where λ is the wavelength of light passing through the lens group and incident on the first optical diffraction element, and d is the cell size of each microcell constituting the first optical diffraction element.

4. An optical computing device as claimed in any one of claims 1 to 3, characterized in that the lens group is composed of a single imaging lens, and the imaging lens is arranged so that a point on the specific plane and a point on the incident surface of the first optical diffraction element are substantially conjugate with respect to the imaging lens.

5. An optical computing device according to any one of claims 1 to 3, characterized in that the lens group is composed of a single Fourier lens, and the Fourier lens is positioned so that a point at infinity and a point on the incident surface of the first optical diffraction element are substantially conjugate with respect to the Fourier lens.

6. An optical computing device according to any one of claims 1 to 3, characterized in that the lens group is composed of a plurality of relay lenses, and the plurality of relay lenses are arranged so that a point on the specific plane and a point on the incident surface of the first optical diffraction element are substantially conjugate with respect to the lens group.

7. The optical computing device according to claim 6, wherein the plurality of relay lenses have a magnifying function of making the image of the object formed on the incident surface of the first optical diffraction element larger than the object.

8. The optical computing device according to claim 6, wherein the plurality of relay lenses have a reduction function of making the image of the object formed on the incident surface of the first optical diffraction element smaller than the object.

9. The optical computing device according to any one of claims 1 to 8, further comprising a constraint mechanism for constraining the object to the specific plane.

10. The optical computing device according to any one of claims 1 to 8, further comprising a moving body that moves the optical diffraction element group and the lens group so that the object is positioned on the specific plane.

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