Patent ID: 12242079

DETAILED DESCRIPTION

Configuration of Light Diffraction Element

The following description will discuss a configuration of a light diffraction element1in accordance with one or more embodiments of the present invention with reference toFIG.1andFIG.2.FIG.1is a plan view illustrating the light diffraction element1.FIG.2is a perspective view in which a part (surrounded by the dashed lines inFIG.1) of the light diffraction element1is magnified.

The light diffraction element1is a planar light diffraction element and is constituted by a plurality of microcells (an example of “cell” in claims). Here, the term “microcell” refers to, for example, a cell having a cell size of less than 10 μm. The term “cell size” refers to a square root of an area of a cell. For example, when a shape of a microcell in a plan view is a square shape, the cell size is a length of one side of the cell. A lower limit of the cell size is not particularly limited and can be, for example, 1 nm.

The light diffraction element1illustrated inFIG.1is constituted by 12×12 microcells which are arranged in a matrix manner. A shape of each of the microcells in a plan view is a square shape having a size of 1 μm×1 μm, and a shape of the light diffraction element1in a plan view is a square shape having a size of 12 μm×12 μm.

Each of the microcells includes a first region C1which selectively allows a first polarized component contained in signal light to pass through, and a second region C2which selectively allows a second polarized component contained in the signal light to pass through. In the microcells, thicknesses or refractive indices of the respective first regions C1are independently set. According to the configuration, phase change amounts of the first polarized components passing through the microcells are independently set. Meanwhile, the second regions C2in the respective microcells are set to have uniform thicknesses or uniform refractive indices. According to the configuration, phase conversion amounts of the second polarized components passing through the microcells are uniformly set. Therefore, the light diffraction element1selectively acts on the first polarized components of signal light. That is, the light diffraction element1causes only the first polarized components of signal light, which have passed through the microcells, to interfere with each other to carry out (i.e., perform) predetermined optical computing. Therefore, the first polarized components of an optical signal output from the light diffraction element1become an optical signal indicative of information after the computing, while the second polarized components of signal light output from the light diffraction element1become an optical signal indicative of information before the computing. Here, “selectively allowing the first polarized components to pass through” and “selectively acting on the first polarized components” mean, in other words, that “a transmittance of the first polarized components is higher than a transmittance of the second polarized components”. Moreover, “selectively allowing the second polarized components to pass through” means, in other words, that “a transmittance of the second polarized components is higher than a transmittance of the first polarized components”.

Note that the first polarized components (on which the light diffraction element1acts) only need to be polarized components having the polarization direction different from that of the second polarized components (on which the light diffraction element1does not act). For example, it is possible to set X polarized light (which is linear polarized light whose polarization plane is parallel to a Z-X plane) is set as the first polarized component, and Y polarized light (which is linear polarized light whose polarization plane is parallel to a Y-Z plane) is set as the second polarized component. Alternatively, it is possible that right circular polarized light is set as the first polarized component, and left circular polarized light is set as the second polarized component. In one or more embodiments, as the light diffraction element1, a light diffraction element in the former form, i.e., the light diffraction element1which selectively acts on X polarized light is employed. In other words, the light diffraction element1in which the transmittance of X polarized light is higher than the transmittance of Y polarized light is employed.

Each of the first regions C1and the second regions C2in the microcells of the light diffraction element1which selectively acts on X polarized light can be constituted by, for example, a pillar that has an emission surface on which a polarizing filter is provided (seeFIG.2). The polarizing filter that is provided on the emission surface of the pillar constituting the first region C1is a polarizing filter which selectively allows X polarized light to pass through (i.e., the transmittance of X polarized light is higher than the transmittance of Y polarized light). The polarizing filter that is provided on the emission surface of the pillar constituting the second region C2is a polarizing filter which selectively allows Y polarized light to pass through (i.e., the transmittance of Y polarized light is higher than the transmittance of X polarized light). This makes it possible to set the phase change amount with respect to X polarized light of each microcell in accordance with the height of the pillar, while setting the phase change amounts with respect to Y polarized light of the microcells to be uniform. That is, it is possible to provide the light diffraction element1which selectively acts on X polarized light. Note that, as the polarizing filter, it is possible to use, for example, a metasurface. The polarizing filter can be provided on an incidence surface of each pillar instead of being provided on the emission surface of each pillar, or can be provided on both the incidence surface and the emission surface of each pillar.

The thickness or refractive index of the first region C1of each of the microcells can be set, for example, by using machine learning. A model that is used in the machine learning can be, for example, a model to which an intensity distribution of signal light input to the light diffraction element1is input, and from which an intensity distribution of the first polarized components of signal light output from the light diffraction element1is output. Furthermore, the model contains thicknesses or refractive indices of the first regions C1of the microcells as parameters.

[First Optical Computing System]

With use of the light diffraction element1, it is possible to optically perform computing for deriving a sum signal of a signal before the computing and a signal after the computing.FIG.3is a perspective view illustrating a main part configuration of an optical computing system10A for carrying out such optical computing.

The optical computing system10A includes a light-emitting device2and a light-receiving device3, in addition to the light diffraction element1.

The light-emitting device2is a device for emitting signal light that is to be input to the light diffraction element1. The light-emitting device2has a plurality of cells which are arranged in a matrix manner and is constituted by, for example, a two-dimensional display. The cells in the light-emitting device2correspond to respective microcells of the light diffraction element1(i.e., one-to-one correspondence). Light output from each of the cells of the light-emitting device2includes the first polarized component and the second polarized component, and is input to a corresponding microcell of the light diffraction element1. In one or more embodiments, a traveling direction of signal light is a positive Z axis direction, the first polarized component is an X polarized component, and the second polarized component is a Y polarized component.

The light-receiving device3is a device for detecting signal light that has been output from the light diffraction element1. The light-receiving device3has a plurality of cells which are arranged in a matrix manner and is constituted by, for example, a two-dimensional image sensor. The cells in the light-receiving device3correspond to respective microcells of the light diffraction element1(i.e., one-to-one correspondence). An X polarized component of signal light which has passed through each of the microcells of the light diffraction element1interferes with X polarized components of signal light which have passed through the other microcells of the light diffraction element1, and is input to each of the cells of the light-receiving device3. Meanwhile, a Y polarized component of signal light which has passed through each of the microcells of the light diffraction element1does not interfere with Y polarized components of signal light which have passed through the other microcells of the light diffraction element1, and is input to a cell of the light-receiving device3corresponding to that microcell. The cells of the light-receiving device3detect signal light output from the light diffraction element1without distinguishing between the X polarized components and the Y polarized components. Therefore, signal light detected by the light-receiving device3indicates a sum signal of a signal before the computing and a signal after the computing.

As described above, according to the optical computing system10A, it is possible to achieve, with use of the light diffraction element1, optical computing for deriving a sum signal of a signal before the computing and a signal after the computing. As an example, the optical computing system10A can be suitably used for a defect extraction operation for extracting a defect of a subject from an image. In this case, when an original image is displayed on the light-emitting device2which is a display device, the light-receiving device3which is an image sensor can detect a synthetic image in which a defect image including only a defect extracted from the original image as a subject is superimposed on the original image.

In one or more embodiments, the configuration is employed in which one light diffraction element1is provided on an optical path of light output from the light-emitting device2, and light which has passed through the light diffraction element1is input to the light-receiving device3. Note, however, that the present invention is not limited to this configuration. For example, it is possible to employ a configuration in which a plurality of light diffraction elements are provided on an optical path of light output from the light-emitting device2, and light which has passed through the light diffraction elements is input to the light-receiving device3. With the configuration, it is possible to provide the optical computing system10A which can sequentially carry out a plurality of types of optical computing. In this case, the light diffraction element1which selectively acts on X polarized light only needs to be included in the plurality of light diffraction elements as at least one of the light diffraction elements.

[Second Optical Computing System]

With use of the light diffraction element1, it is possible to optically perform a plurality of types of optical computing for deriving a signal before the computing and a signal after the computing, respectively.FIG.4is a perspective view illustrating a main part configuration of an optical computing system10B for carrying out such a plurality of types of optical computing.

The optical computing system10B includes a light-emitting device2, light-receiving devices3aand3b, a polarized beam splitter4, and a mirror5, in addition to the light diffraction element1.

The light-emitting device2is identical with the light-emitting device2provided in the optical computing system10A. The light-emitting device2has a plurality of cells which are arranged in a matrix manner and is constituted by, for example, a two-dimensional display. The cells in the light-emitting device2correspond to respective microcells of the light diffraction element1(i.e., one-to-one correspondence). Light output from each of the cells of the light-emitting device2includes the first polarized component and the second polarized component, and is input to a corresponding microcell of the light diffraction element1. In one or more embodiments, a traveling direction of signal light is a positive Z axis direction, the first polarized component is an X polarized component, and the second polarized component is a Y polarized component.

The polarized beam splitter4is an optical element which allows the X polarized components of signal light output from the light diffraction element1to pass through, and reflects the Y polarized components of the signal light output from the light diffraction element1. The X polarized components of signal light which have passed through the polarized beam splitter4are input to the light-receiving device3a. The Y polarized components of signal light which have been reflected by the polarized beam splitter4are further reflected by the mirror5and are then input to the light-receiving device3b.

The light-receiving device3ais a device for detecting the X polarized components of signal light which have been passed through the polarized beam splitter4. The light-receiving device3ahas a plurality of cells which are arranged in a matrix manner and is constituted by, for example, a two-dimensional image sensor. The cells in the light-receiving device3acorrespond to respective microcells of the light diffraction element1(i.e., one-to-one correspondence). An X polarized component of signal light which has passed through each of the microcells of the light diffraction element1interferes with X polarized components of signal light which have passed through the other microcells of the light diffraction element1, and is input to each of the cells of the light-receiving device3. The signal light detected by the light-receiving device3aindicates a signal after the computing.

The light-receiving device3bis a device for detecting the Y polarized components of signal light which have been reflected by the polarized beam splitter4. The light-receiving device3bhas a plurality of cells which are arranged in a matrix manner and is constituted by, for example, a two-dimensional image sensor. The cells in the light-receiving device3acorrespond to respective microcells of the light diffraction element1(i.e., one-to-one correspondence). A Y polarized component of signal light which has passed through each of the microcells of the light diffraction element1does not interfere with Y polarized components of signal light which have passed through the other microcells of the light diffraction element1, and is input to a cell of the light-receiving device3corresponding to that microcell. The signal light detected by the light-receiving device3bindicates a signal before the computing.

As described above, according to the optical computing system10B, it is possible to achieve, with use of the light diffraction element1, a plurality of types of optical computing for deriving a signal before the computing and a signal after the computing, respectively. As an example, the optical computing system10B can be suitably used for a defect extraction operation for extracting a defect of a subject from an image. In this case, when an original image is displayed on the light-emitting device2which is a display device, the light-receiving device3awhich is an image sensor can detect a defect image including only a defect extracted from the original image as a subject, and the light-receiving device3bwhich is an image sensor can detect the original image.

In one or more embodiments, the configuration is employed in which one light diffraction element1is provided on an optical path of light output from the light-emitting device2, and light which has passed through the light diffraction element1is input to the polarized beam splitter4. Note, however, that the present invention is not limited to this configuration. For example, it is possible to employ a configuration in which a plurality of light diffraction elements are provided on an optical path of light output from the light-emitting device2, and light which has passed through the light diffraction elements is input to the polarized beam splitter4. With the configuration, it is possible to provide the optical computing system10B which can sequentially carry out a plurality of types of optical computing. In this case, the light diffraction element1which selectively acts on X polarized light only needs to be included in the plurality of light diffraction elements as at least one of the light diffraction elements.

Embodiments of the present invention can also be expressed as follows:

The light diffraction element in accordance with one or more embodiments of the present invention is a light diffraction element constituted by a plurality of cells. In the light diffraction element in accordance with one or more embodiments of the present invention, first regions of respective of the plurality of cells allow first polarized components to pass through and have respective thicknesses or refractive indices that are independently set; and second regions of respective of the plurality of cells allow second polarized components to pass through and have uniform thicknesses or uniform refractive indices, the second polarized components being different in polarization direction from the first polarized components.

According to the configuration, it is possible to provide the light diffraction element which can output signal light indicative of information after the computing as the first polarized component, and output information before the computing as the second polarized component.

The light diffraction element in accordance with one or more embodiments of the present invention may additionally employ a configuration in which: the first polarized components of signal light which have passed through the first regions of respective of the plurality of cells are caused to interfere with each other so as to carry out predetermined computing; the first polarized components of signal light output from the light diffraction element indicate information after the computing; and the second polarized components of signal light output from the light diffraction element indicate information before the optical computing.

According to the configuration, it is possible to provide the light diffraction element which can output signal light indicative of information after the computing as the first polarized component, and output information before the computing as the second polarized component.

The light diffraction element in accordance with one or more embodiments of the present invention may additionally employ a configuration in which: the first region of each of the plurality of cells is constituted by a pillar having a height that is independently set; and a polarizing filter which selectively allows the first polarized components to pass through is provided on an emission surface or an incidence surface of the pillar.

According to the configuration, it is possible to easily produce the light diffraction element which can output signal light indicative of information after the computing as the first polarized component, and output information before the computing as the second polarized component.

An optical computing system in accordance with one or more embodiments of the present invention may additionally include: a light-emitting device that outputs signal light to be input to the light diffraction element; and a light-receiving device that detects, without distinction, the first polarized components and the second polarized components of signal light which is output from the light diffraction element.

According to the configuration, it is possible to optically perform computing for deriving a sum signal of a signal before the computing and a signal after the computing. As an example, it is possible to optically perform computing for deriving a synthetic image containing an image before the computing and an image after the computing.

The optical computing system in accordance with one or more embodiments of the present invention may additionally include a light-emitting device that outputs signal light to be input to the light diffraction element; a first light-receiving device that detects the first polarized components of signal light output from the light diffraction element: and a second light-receiving device that detects the second polarized components of the signal light output from the light diffraction element.

According to the configuration, it is possible to optically perform a plurality of types of computing for deriving a signal before the computing and a signal after the computing, respectively. As an example, it is possible to optically perform a plurality of types of computing for deriving an image before the computing and an image after the computing, respectively.

Note that the “light diffraction element” in this specification is an element for converting an optical signal indicative of certain information (for example, a certain image) into an optical signal indicative of other information (for example, another image). Therefore, the “light diffraction element” in this specification can alternatively be referred to as “optical filter”, as in a case in which an element for converting an electrical signal indicative of a certain image into an electrical signal indicative of another image is called “filter”. The “optical computing system” in this specification carries out optical computing with use of a light diffraction element, that is, an optical filter.

Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present invention. Accordingly, the scope of the invention should be limited only by the attached claims.

REFERENCE SIGNS LIST

1: Light diffraction element10A,10B: Optical computing system2: Light-emitting device3: Light-receiving device4: Polarized beam splitter5: Mirror