Modulator and imaging device

Abstract

A modulator (300) according to an embodiment is disposed between a diffraction grating (944) and an image sensor (946), wherein: light rays travelling from the diffraction grating (944) towards the image sensor (946) are incident thereon; and the direction of advancement of light rays projected toward the image sensor (946) is changed so that, on the light receiving surface of the image sensor (946), the recording directions for diffraction images of each wavelength of light ray bend.

Description

[Technical field]

[0001] The present disclosure relates to a modulator. and Imaging equipment Place Regarding. [Background technology]

[0002] Conventionally, spectroscopic measurement techniques have been known as a method for analyzing the composition of an object. Spectroscopic measurement techniques are a method for analyzing the composition (elements, molecular structure, etc.) of an object by analyzing the light emitted from, reflected from, or transmitted through the object.

[0003] The wavelength components of light emitted from, reflected from, or transmitted through an object vary depending on the composition of the object. Therefore, by analyzing these wavelength components, the composition of the object can be analyzed. In general, data that indicates the amount of each wavelength is called a wavelength spectrum, and the process of measuring a wavelength spectrum is called spectroscopic measurement processing.

[0004] In order to analyze the composition of each point on the surface of an object, it is necessary to obtain corresponding data between the spatial information and wavelength information of the object. The snapshot method is known as a method for obtaining corresponding data between the spatial information and wavelength information of an object in a single process, i.e., in a single photographing process by a spectroscopic measurement device. A spectroscopic measurement device that applies the snapshot method is configured by combining an optical system consisting of multiple lenses, slits (field stop), spectroscopic elements, etc., with a sensor. The spatial resolution and wavelength resolution of the spectroscopic measurement device are determined by the configuration of these optical systems and sensors. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-90576 A [Non-patent literature]

[0006] [Non-Patent Document 1] Habel, R., Kudenov, M., Wimmer, M.: Practical spectral photography. Computer Graphics Forum (Proceedings EUROGRAPHICS 2012) 31(2), 449-458 (2012) [Non-Patent Document 2] Tebow, Christopher P.; Dereniak, Eustace L.; Garrood, Dennis; Dorschner, Terry A.; Volin, Curtis E.: Tunable snapshot imaging spectrometer. Proceedings of the SPIE, Volume 5159, p. 64-72 (2004) [Non-Patent Document 3] Dwight JG, Tkaczyk TS.: Lenslet array tunable snapshot imaging spectrometer (LATIS) for hyperspectral fluorescence microscopy. Biomed Opt Express. 2017;8:1950-64 Summary of the Invention [Problem to be solved by the invention]

[0007] Here, spectroscopic elements such as prisms and diffraction gratings that are commonly used in spectroscopic measurement devices disperse incident light in one or two axial directions according to its wavelength. On the other hand, the imaging area of ​​an image sensor for capturing a spectral image is usually a rectangular area. This means that there are many imaging areas on the image sensor where no spectral image is incident.

[0008] As described above, with a conventional general spectroscopic element, it has been difficult to efficiently use the imaging area of ​​an image sensor used in a spectroscopic measurement device or the like.

[0009] Therefore, the present disclosure proposes a modulator, an imaging device, and a design method that enable more efficient use of the imaging area of ​​an image sensor. [Means for solving the problem]

[0010] In order to solve the above problems, one form of modulator according to the present disclosure is a modulator that is provided between a diffraction grating and an image sensor, in which a light beam traveling from the diffraction grating toward the image sensor is incident and the direction of the light beam emitted toward the image sensor is changed so that the recording direction of the diffraction image for each wavelength of the light beam on the light receiving surface of the image sensor is curved.

[0011] Moreover, one form of imaging device according to the present disclosure includes a diffraction grating, an image sensor having the diffraction grating arranged on the light receiving surface side, and a modulator arranged between the diffraction grating and the image sensor, wherein the modulator changes the direction of travel of a light beam emitted toward the image sensor when the light beam travels from the diffraction grating toward the image sensor so that the recording direction of a diffraction image for each wavelength of the light beam on the light receiving surface of the image sensor is curved.

[0012] Furthermore, one form of design method according to the present disclosure is a design method for a modulator that changes the direction of travel of a light ray incident from a diffraction grating and outputs it to an image sensor, the design method including tracking the spatial behavior of the incident light ray and the exiting light ray of the modulator, determining a surface normal of the modulator based on the incident light ray and the exiting light ray, and integrating the surface normal to determine a shape of the modulator. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a diagram illustrating the relationship between the type of light and its wavelength. [Diagram 2] 1A and 1B are diagrams illustrating an example of spectroscopic measurement of a light-emitting object. [Diagram 3] FIG. 13 is a diagram showing an example of a spectral intensity analysis result that is a spectral analysis result of output light of a certain food. [Figure 4]FIG. 2 is a diagram illustrating a prism that is a light separating element. [Diagram 5] FIG. 2 is a diagram illustrating a light-dispersing grating which is a spectroscopic element. [Figure 6] FIG. 1 is a diagram illustrating an example of a data cube that is three-dimensional data in the spatial directions (XY) and the wavelength direction (λ) of the object to be measured. [Figure 7] FIG. 1 is a diagram illustrating an example of the schematic configuration of a spectroscopic measurement device using a point measurement method (spectrometer). [Figure 8] FIG. 13 is a diagram showing an example of data acquired in one imaging process using a point measurement type spectroscopic measurement device. [Figure 9] FIG. 1 is a diagram illustrating an example of a schematic configuration of a wavelength scanning spectroscopic measurement device. [Figure 10] FIG. 1 is a diagram showing an example of data acquired in one imaging process using a wavelength scanning spectroscopic measurement device. [Figure 11] FIG. 1 is a diagram illustrating an example of a schematic configuration of a spatial scanning spectroscopic measurement device. [Figure 12] FIG. 1 is a diagram showing an example of data acquired in one imaging process using a spatial scanning spectroscopic measurement device. [Figure 13] FIG. 1 is a diagram illustrating an example of a schematic configuration of a snapshot-type spectroscopic measurement device. [Figure 14] FIG. 13 is a diagram showing an example of data acquired in one imaging process using a snapshot-type spectroscopic measurement device. [Figure 15] FIG. 13 is a diagram showing a modified example of a snapshot type spectroscopic measurement device. [Figure 16] FIG. 1 is a diagram for explaining a data cube restoration method in the snapshot method. [Figure 17] 1A and 1B are diagrams for explaining the principle of light separation by a slit-type diffraction grating. [Figure 18] FIG. 2 is a diagram showing an example of an image of light dispersed by a lattice-type diffraction grating. [Figure 19] FIG. 1 is a diagram showing the relationship between the wavelength of incident light and the diffraction angle. [Figure 20]FIG. 1 is a diagram for explaining the problems with the snapshot method (part 1). [Figure 21] FIG. 2 is a diagram for explaining the problems with the snapshot method (part 2). [Figure 22] FIG. 1 is a diagram for explaining a first problem in a method for adjusting wavelength resolution and spatial resolution by controlling a grating interval. [Diagram 23] FIG. 11 is a diagram for explaining a second problem in the method of adjusting the wavelength resolution and the spatial resolution by controlling the grating spacing. [Figure 24] 1A to 1C are diagrams showing an example of a projected image of a basic diffraction grating on a light receiving surface and a projected image when a modulator according to an embodiment is used. [Diagram 25] 1 is a diagram illustrating an example of a schematic configuration of a snapshot-type spectroscopic measurement device according to an embodiment. [Figure 26] 4 is a diagram illustrating an example of a relationship between a modulator and image data of the spectroscopic measurement apparatus according to the embodiment. FIG. [Figure 27] FIG. 1 is a diagram for explaining a light beam in a conventional spectroscopic measurement device using a snapshot method. [Figure 28] 1 is a diagram for explaining an example of the arrangement of a spectroscopic measurement device according to an embodiment; [Figure 29] 1 is a flowchart showing the steps of a method for designing a modulator according to an embodiment. [Diagram 30] 1A to 1C are diagrams for explaining an example of a method for designing a modulator according to an embodiment. [Diagram 31] 6A to 6C are diagrams illustrating simulation results of the spectroscopic measurement device according to the embodiment. [Diagram 32] 11A and 11B are diagrams for explaining an example of the arrangement of a spectroscopic measurement device according to a modified example of the embodiment. [Diagram 33] 13 is a flowchart showing the steps of a method for designing a modulator according to a modified example of the embodiment. [Diagram 34] 1 is a block diagram showing a schematic configuration example of a vehicle control system that is an example of a mobile object control system to which the technology according to the present disclosure can be applied. [Diagram 35]35 is a diagram showing an example of an installation position of the imaging unit shown in FIG. 34. [Diagram 36] 1 is a diagram showing an example of a schematic configuration of an endoscopic surgery system to which the technology according to the present disclosure (the present technology) can be applied. [Figure 37] 37 is a block diagram showing an example of the functional configuration of the camera head and the CCU shown in FIG. 36. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. In the following embodiments, the same components are designated by the same reference numerals, and duplicated descriptions will be omitted.

[0015] The present disclosure will be described in the following order. 1. Overview of the spectroscopic measurement device (system) 2. Issues with the snapshot method 3. Embodiment 3.1 Overview of spectroscopic measurement equipment 3.2 Modulator placement 3.3 Modulator design example 3.4 Simulation results 3.5 Actions and Effects 3.6 Modifications of the embodiment 3.7 Modulator design example according to the modified embodiment 3.8 Mobile application examples 3.9 Application example to endoscopic surgery system

[0016] 1. Overview of the spectroscopic measurement device (system) First, an overview of the spectroscopic measurement device (system) will be described. Light includes, for example, infrared radiation, visible light, and ultraviolet light, which are types of electromagnetic waves and have different wavelengths (oscillation periods) depending on the type of light, as shown in Figure 1.

[0017] Visible light has a wavelength in the range of approximately 400 nm to 700 nm. Infrared radiation has a longer wavelength than visible light, while ultraviolet radiation has a shorter wavelength than visible light.

[0018] As mentioned above, the light emitted from an object, reflected light, or transmitted light has different optical wavelength components depending on the composition of the object (elements, molecular structure, etc.), and analyzing these wavelength components makes it possible to analyze the composition of the object. In general, data indicating the amount of each wavelength is called a wavelength spectrum, and the process of measuring a wavelength spectrum is called spectroscopic measurement processing.

[0019] Fig. 2 is a diagram showing an example of spectroscopic measurement of a light-emitting object. Fig. 2 shows which wavelengths of light in the visible light wavelength range (approximately 400 nm to 700 nm) are emitted by the sun, electric lamps, neon, hydrogen, mercury, and sodium. Areas with output are displayed in whitish light, and areas without output are displayed in black. Fig. 2 shows the results of spectroscopic measurement of the output light from sunlight, electric lamps, and various heated substances.

[0020] As shown in Figure 2, the sun, electric light, neon, hydrogen, mercury, and sodium each emit light with wavelengths unique to each object. In other words, even if the object is unknown, it is possible to analyze the composition of the object by analyzing the wavelength components contained in the light from the object.

[0021] For example, if the composition of a certain processed food is unknown, it is possible to analyze the substances that compose the food by analyzing the output light (emitted light, reflected light, or transmitted light) of the food. Figure 3 shows an example of a spectral intensity analysis result, which is a spectroscopic analysis result of the output light of a certain food. Two different types of spectral analysis results are obtained from this food.

[0022] By comparing the results of this spectral intensity analysis with spectral intensity analysis data obtained in advance from analyses of various substances, it is possible to determine the identities of substance A and substance B, and thus to analyze the composition of the food.

[0023] As mentioned above, spectroscopic measurement makes it possible to obtain various information about the object being measured. However, with a general camera that has a condenser lens and a sensor, light with a mixture of all wavelengths enters each pixel of the sensor, making it difficult to analyze the intensity of each wavelength unit.

[0024] Therefore, the spectroscopic measurement observation system is provided with a spectroscopic element (spectroscopic device) to separate light of each wavelength from the light entering the camera.

[0025] The most commonly known spectroscopic element is a prism 901 shown in Fig. 4. Light incident on the prism 901, i.e., light of various wavelengths contained in the incident light, is emitted from the prism 901 at an emission angle corresponding to the wavelength of the incident light, the angle of incidence, and the shape of the prism 901. An observation system for spectroscopic measurement is provided with a spectroscopic element such as this prism 901, and is configured to enable light in wavelength units to be individually received by a sensor.

[0026] In addition, in the case of dispersion by a prism with a refractive index n, the equation showing the change in the direction of travel of light by the prism can be expressed by the following equation (1).

number

[0027] The parameters in the above formula (1) are as follows: α: Prism apex angle θ1: Incident angle to the prism entrance surface θ2: Exit angle relative to the prism exit surface φ1: Refraction angle of the prism entrance surface φ2: Refraction angle of the prism exit surface δ: deviation angle (angle between incident and outgoing light)

[0028] Here, Snell's law (sinθ j =nsinΦ j ), the above equation (1) can be rewritten as the following equation (2).

number

[0029] In the above formula (2), n is the refractive index of the prism, and the refractive index n depends on the wavelength. Also, φ1 is the refraction angle of the prism entrance surface, and depends on the refractive index n of the prism and the incident angle θ1 to the prism entrance surface. Therefore, the deviation angle (angle between the incident light and the outgoing light) δ depends on the incident angle θ1 and the wavelength.

[0030] 5, light can also be separated by a diffraction grating 902 that utilizes the wave nature of light. The emission angle (diffraction angle) β of a light beam from the diffraction grating 902 can be expressed by the following formula (3).

number

[0031] However, analyzing the wavelength information of light from a single point on an object only allows us to analyze the composition of that single point. In other words, to analyze the composition of each point on the surface of an object with a single observation, it is necessary to analyze all of the light from each point on the surface.

[0032] In order to analyze the composition of each point on the surface of a measurement object, it is necessary to obtain three-dimensional data in the spatial directions (XY) and wavelength direction (λ) of the measurement object in a single observation. Figure 6 shows an example of three-dimensional data in the spatial directions (XY) and wavelength direction (λ) of the measurement object, i.e., a data cube.

[0033] As shown in Fig. 6, a data cube is three-dimensional data consisting of the spatial directions (XY) and wavelength direction (λ) of the object to be measured, where the coordinates of each point on the surface of the object to be measured are indicated by XY coordinates, and the intensity (λ) of each wavelength of light at each coordinate position (x, y) is recorded. The data cube shown in Fig. 6 is composed of 8 x 8 x 8 cube data, and one cube D is data indicating the light intensity of a specific wavelength (λ) at a specific position (x, y).

[0034] It should be noted that the number of cubes shown in FIG. 6, 8×8×8, is just an example, and this number will vary depending on the spatial resolution and wavelength resolution of the spectroscopic measurement device.

[0035] Next, an example of an existing spectroscopic measurement device that acquires a data cube as shown in FIG. 6, that is, three-dimensional data in the spatial direction (XY) and the wavelength direction (λ) of the measurement object, will be described.

[0036] Existing spectroscopic measurement devices that obtain three-dimensional data of an object in the spatial direction (XY) and wavelength direction (λ) can be classified into the following four types. (a) Point measurement method (spectrometer) (b) Wavelength scanning method (c) Space scanning method (d) Snapshot method Below, we will provide an overview of each of these methods.

[0037] (a) Point measurement method (spectrometer) Fig. 7 is a diagram showing a schematic configuration example of a spectroscopic measurement device using a point measurement method (spectrometer), and Fig. 8 is a diagram showing an example of data acquired in one imaging process using the spectroscopic measurement device using the point measurement method.

[0038] 7, the point measurement type spectroscopic measurement device includes a light source 911, a slit 912, a prism 913, and a linear sensor 914, and is configured to disperse light emitted from one point on a measurement target 900 using the prism 913, which is a spectroscopic element, and project the dispersed light onto a linear sensor 914, which has elements arranged in only one direction. With this configuration, light of different wavelengths is recorded on different elements (pixels) on the linear sensor 914.

[0039] In the point measurement method, the wavelength spectrum is obtained by reading the value of each element (pixel) of the linear sensor 914. A feature of this point measurement method is that the wavelength resolution depends on the element size (number of pixels) of the linear sensor 914, and the more the number of elements (number of pixels) is increased, the more fine wavelength information can be obtained.

[0040] However, in the point measurement method, in one imaging process, light emitted from one point on the measurement object 900 is received and analyzed. Therefore, as shown in Fig. 8, in one imaging process, wavelength information (λ) of only one point in the spatial direction (XY) of the measurement object 900 can be obtained. Therefore, in order to obtain wavelength information (λ) of various points in the spatial direction (XY) of the measurement object 900, it is necessary to perform imaging and analysis many times while shifting the measurement position.

[0041] (b) Wavelength scanning method Fig. 9 is a diagram showing a schematic configuration example of a wavelength scanning spectroscopic measurement device, and Fig. 10 is a diagram showing an example of data acquired in one imaging process using the wavelength scanning spectroscopic measurement device.

[0042] As shown in Figure 9, a wavelength scanning spectroscopic measurement device has a wavelength filter array 921 and an area sensor (two-dimensional image sensor) 923, and captures images by switching between multiple optical filters 922 with different wavelength passing characteristics arranged in front of the area sensor 923 at regular intervals.

[0043] According to such a procedure, it is possible to obtain intensity information of one wavelength corresponding to multiple spatial positions in one shooting, as shown in Fig. 10. Then, by switching the optical filter 922 and shooting, it is possible to obtain intensity information of multiple different wavelengths.

[0044] However, in order to achieve high wavelength resolution, it is necessary to prepare a large number of different optical filters 922 and switch between them to capture images, which results in a problem of long measurement time. In addition, there is also a problem that some wavelength bands cannot be captured due to the characteristics of the optical filters 922.

[0045] (c) Space scanning method Fig. 11 is a diagram showing a schematic configuration example of a spatial scanning spectroscopic measurement device, and Fig. 12 is a diagram showing an example of data acquired in one imaging process using the spatial scanning spectroscopic measurement device.

[0046] As shown in Fig. 11, the spatial scanning spectroscopic measurement device includes an objective lens 931, a slit 932, a collimator lens 933, a spectroscopic element 934, an imaging lens 935, and an area sensor 936, and records one spatial direction in the X direction of the area sensor and a wavelength direction in the Y direction of the area sensor for light from a measurement object 900 that has been dispersed by a spectroscopic element (prism, diffraction grating, etc.) 934. Furthermore, as shown in Fig. 12, the spectroscopic measurement device scans the measurement object 900 in the remaining direction. This process makes it possible to obtain the data cube previously described with reference to Fig. 6, that is, a three-dimensional data cube in the spatial directions (XY) and the wavelength direction (λ) of the measurement object 900.

[0047] This spatial scanning method can achieve high spatial and wavelength resolution, but it has the drawbacks of requiring a large device for scanning and long measurement times due to the scanning processing time.

[0048] (d) Snapshot method Fig. 13 is a diagram showing a schematic configuration example of a snapshot-type spectroscopic measurement device, and Fig. 14 is a diagram showing an example of data acquired in one imaging process using the snapshot-type spectroscopic measurement device.

[0049] 13, the snapshot type spectroscopic measurement device includes an objective lens 941, a slit 942, a collimating lens 943, a diffraction grating type spectroscopic element (hereinafter simply referred to as a diffraction grating) 944, an imaging lens 945, and an area sensor 946, and is configured to collect light from a measurement target 900 by the objective lens 941, convert the light into parallel light by the collimating lens 943, transmit the light through the diffraction grating 944, and project the light onto the light receiving surface of the area sensor 946. The light receiving surface may be a surface on which photoelectric conversion units such as photodiodes in an image sensor (also referred to as a solid-state imaging device) are arranged.

[0050] With this configuration, light of different wavelength components from different points on the measurement object 900 is recorded by different elements (pixels) on the light receiving surface of the area sensor 946.

[0051] This snapshot method can acquire the data cube described with reference to FIG. 6 in a single shooting, i.e., a three-dimensional data cube in the spatial directions (XY) and the wavelength direction (λ) of the measurement object 900 as shown in FIG. 14.

[0052] However, the light receiving area of ​​the area sensor 946 is finite, and information in the wavelength direction is recorded overlapping on the light receiving surface, so that after shooting, a process is required to restore the data cube by signal processing.

[0053] In addition, since the various coefficients used in signal processing are linked to the performance of the optical system, the optical system must be fixed, i.e., the positional relationship between the sensor and the optical system must be fixed, which poses the problem that it is difficult to adjust the wavelength and spatial resolution to suit the application purpose.

[0054] As an application example of the snapshot method shown in Fig. 13, a configuration has been proposed in which optical filters 947 having different transmission bands are spatially arranged on the light receiving surface of an area sensor 946 to obtain a data cube, as shown in Fig. 15. However, the light receiving area is finite, and it is necessary to attach the optical filter 947 to the light receiving surface of the area sensor 946, which causes a problem that the spatial resolution of the area sensor 946 decreases due to the attachment of the optical filter 947.

[0055] With reference to Figures 7 to 14, we have described four examples of existing spectroscopic measurement devices that acquire three-dimensional data in the spatial direction (XY) and wavelength direction (λ) of the object to be measured: (a) point measurement method (spectrometer), (b) wavelength scanning method, (c) spatial scanning method, and (d) snapshot method.

[0056] Among these four methods, the (d) snapshot method described with reference to FIGS. 13 and 14 is particularly useful because it allows a data cube to be acquired by photographing once.

[0057] Furthermore, to solve the problem of the difficulty in adjusting the wavelength resolution, a configuration using a diffraction grating that can be retrofitted into an existing optical system is more suitable than a sensor configuration in which the sensor and filter are integrated.

[0058] Therefore, in this disclosure, several examples of snapshot-type spectroscopic measurement devices using a diffraction grating, for example, spectroscopic measurement devices using a computed tomography imaging spectrometer (CTIS), will be described below.

[0059] 2. Issues with the snapshot method Here, a method for restoring a data cube in the snapshot method will be described with reference to Fig. 16. Fig. 16 illustrates an example in which an image of a measurement target 900 is captured by a spectroscopic measurement device 940 in the snapshot method that includes a lattice-shaped diffraction grating 944 (see Fig. 13).

[0060] As shown in FIG. 16, when an image of a measurement object 900 is captured (S901) using a spectroscopic measurement device 940 equipped with a diffraction grating 944, the captured image 951 shows diffraction images of ±1st order or higher in a total of eight directions, including up, down, left, right, and diagonal directions, with the diffraction image of zeroth order light located in the center as the center.

[0061] It is possible to restore the data cube g by performing binary matrix arithmetic processing on such a captured image 951 using a previously prepared modulation matrix H. Specifically, the data cube g can be restored by substituting the acquired captured image 951 into the following formula (4). Note that in formula (4), x, y, and λ represent the x coordinate, y coordinate, and wavelength λ of a pixel in the captured image 951 (or the pixel array section of the spectroscopic measurement device 940), and f(x, y, λ) represents the pixel value of the pixel (x, y, λ) in the captured image 951.

number

[0062] The solution to equation (4) can be found by, for example, optimization using the expectation-maximization (EM) algorithm using the following equation (5) (S902). This makes it possible to obtain a data cube (g) 952 in which the horizontal plane is the XY coordinate system and the vertical direction is the wavelength axis. Graph 953 shows the wavelength spectrum of the (x, y) pixel in data cube 952.

number

[0063] In a spectrometer that uses such a snapshot method, a trade-off occurs between spatial resolution and wavelength resolution due to the size constraints of the image sensor that captures the diffraction image. For example, if the dispersion angle is increased to increase the spread of the dispersed light in order to increase the wavelength resolution, the spread of the diffraction image also increases, making it impossible to capture a wide range, and the spatial resolution decreases. On the other hand, if the dispersion angle is reduced to increase the spatial resolution, the overlap of diffraction images of different wavelengths increases, and the wavelength resolution decreases. Furthermore, the wavelength range of the dispersed light incident on one pixel of the image sensor increases as the diffraction image becomes smaller, which also reduces the wavelength resolution.

[0064] This will be explained in more detail. Fig. 17 is a diagram for explaining the principle of light separation by a slit-type diffraction grating. Fig. 18 is a diagram showing an example of an image of light separated by a lattice-type diffraction grating. Fig. 19 is a diagram showing the relationship between the wavelength of incident light and the diffraction angle.

[0065] As shown in Figure 17, light (considered to be a plane wave) incident on the diffraction grating passes through two slits and reaches the screen as a spherical wave. At that time, a difference in optical path length occurs between the light that passes through one slit and the light that passes through the other slit. Therefore, the image of the incident light transferred onto the screen has a pattern of light shading (high and low light intensity) that depends on the difference in optical path length, the wavelength λ of the incident light, and the slit spacing (grating spacing P).

[0066] When this is applied to a lattice-shaped diffraction grating, as shown in the left diagram of Figure 18, the incident light on the diffraction grating is diffracted at different diffraction angles β determined by the above-mentioned equation (3) depending on the wavelength λ and the grating spacing P of the diffraction grating. In equation (3), m is the order. As a result, as shown in the right diagram of Figure 18, the image of the light that has passed through the diffraction grating (diffraction image) is an image in which the 0th order light is at the center, with ±1st order light, ±2nd order light, etc. arranged around it.

[0067] This means that when the lattice spacing P is fixed, the relationship between the wavelength λ and the diffraction angle β becomes a linear relationship as shown in FIG. 19. In FIG. 19, the straight lines P1, P2, and P3 correspond to the lattice spacings P1, P2, and P3, and the lattice spacings P1, P2, and P3 are in the relationship of P1 < P2 < P3.

[0068] From such a relationship, when the lattice spacing P is decreased, the diffraction angle β increases. As a result, as illustrated in FIG. 20, the spread of the diffraction image 961 in the captured image 960 becomes larger, so that it becomes possible to enhance the wavelength resolution. On the other hand, when the lattice spacing P is increased, the diffraction angle β decreases. As a result, as illustrated in FIG. 21, the spread of the diffraction image 962 in the captured image 960 becomes smaller, so that imaging over a wider range becomes possible and it becomes possible to enhance the spatial resolution.

[0069] However, in the method of adjusting the wavelength resolution and the spatial resolution simply by controlling the lattice spacing, the following problems occur.

[0070] FIG. 22 is a diagram for explaining the first problem. As shown in FIG. 22, when the lattice spacing P is decreased, the diffraction angle β increases at all wavelengths at which the diffraction angle β is observed. Therefore, although the range of the diffraction image 971 expands, depending on the settings such as the sensor size of the area sensor, an event may easily occur in which the diffraction image 971 protrudes from the observable range 970 of the area sensor and accurate measurement cannot be performed. This means that the wavelength range to be measured and the wavelength resolution are in a trade-off relationship with each other.

[0071] FIG. 23 is a diagram for explaining the second problem. As shown in FIG. 23, when the lattice interval P is increased, the spread of the entire diffraction image is reduced, so that the spatial resolution can be increased. On the other hand, the overlapping portion of the diffraction images 981 to 985 of each wavelength increases, so that the wavelength resolution decreases. This means that the spatial resolution and the wavelength resolution are in a trade-off relationship. In FIG. 23, the diffraction images 981 to 985 are slightly shifted in the horizontal direction for the sake of understanding, but in reality, they may be aligned in the vertical direction.

[0072] As described above, in conventional snapshot-based spectroscopic measurement devices using diffraction gratings, there is a trade-off between spatial resolution and wavelength resolution, making it difficult to achieve high wavelength resolution while maintaining spatial resolution.

[0073] Therefore, in the following embodiment, a new modulator is proposed, which makes it possible to reduce the trade-off between the observable wavelength range and the spatial resolution.

[0074] 3. Embodiment Next, a modulator and an imaging device according to an embodiment will be described in detail with reference to the drawings. Note that the embodiment is based on the snapshot-type spectroscopic measurement device 940 using a diffraction grating described above with reference to Figures 13, 14, and 16. However, the present embodiment is not limited to this, and can be applied to various optical devices that use a diffraction grating as a spectroscopic element.

[0075] 3.1 Overview of spectroscopic measurement equipment Fig. 24 is a diagram showing an example of a projected image of a basic diffraction grating on a light receiving surface and a projected image when a modulator according to an embodiment is used. Fig. 25 is a diagram showing a schematic configuration example of a snapshot-type spectroscopic measurement device according to an embodiment. Fig. 26 is a diagram showing an example of the relationship between a modulator of the spectroscopic measurement device according to an embodiment and image data.

[0076] In the spectroscopic element in the snapshot type spectroscopic measurement device 940, as shown in the left diagram of FIG. 24, the diffraction images of the image data 100 are recorded linearly according to wavelengths (for example, ±1st order light). That is, the diffraction images are recorded radially, with the 0th order light at the center, as linear images of ±1st order light. Due to this phenomenon, it is difficult to adjust the overlap between images in a sensor space of a finite size, which causes deterioration of the wavelength resolution. For this reason, the spectroscopic measurement device 940A according to the embodiment changes the recording direction of the diffraction images for each wavelength, as in the image data 101 shown in the right diagram of FIG. 24, by bending the light beam emitted from the diffraction grating 944 again by the modulator. In this embodiment, for the sake of simplicity, the modulator is described as bending the diffraction image of the 1st order light, but the diffraction images of the second order light and subsequent orders of light may be bent in the same manner as the 1st order light.

[0077] The spectroscopic measurement device 940A is included in, for example, an imaging device. As shown in Fig. 25, the spectroscopic measurement device 940A includes an objective lens 941, a slit 942, a collimator lens 943, a diffraction grating 944, a modulation lens 948, the modulator 300, an imaging lens 945, and an area sensor 946. The area sensor 946 is an example of an image sensor.

[0078] The modulation lens 948 is provided between the diffraction grating 944 and the modulator 300, and is a lens for combining the diffracted light beams of the diffraction grating 944 by wavelength. The modulation lens 948 has a focal length of f M And f M A focal plane is generated at a distance of

[0079] The modulator 300 is provided between the diffraction grating 944 and the area sensor 946. The modulator 300 is provided on an optical path along which the light beam transmitted through the diffraction grating 944 travels toward the area sensor 946. In the embodiment, the modulator 300 is disposed at the focal position of the modulation lens 948 on the optical path. The modulator 300 is formed into a rectangular shape by a transparent member. The transparent member includes a member having a refractive index, such as glass, synthetic resin, polycarbonate resin, or the like. The shape of the modulator 300 can be, for example, a circular, elliptical, polygonal, or other shape.

[0080] The modulator 300 receives light beams (diffracted light beams) traveling from the diffraction grating 944 toward the area sensor 946. The modulator 300 is configured to change the traveling direction of the incident light beam according to Snell's law. The modulator 300 changes the traveling direction of the light beam emitted toward the area sensor 946 so that the recording direction of the diffraction image for each wavelength of the light beam on the light receiving surface of the area sensor 946 is curved. In other words, the modulator 300 changes the traveling direction of the light beam so that the recording direction of the diffraction image on the light receiving surface of the area sensor 946 is curved.

[0081] For example, as shown in FIG. 26, the modulator 300 receives a group of light beams L1 projecting a diffraction image shown in image data 100 from a diffraction grating 944. The group of light beams L1 is a bundle of light beams in which linear diffraction images of ±1st order light are radially recorded with the 0th order light at the center. In order to obtain a pattern of a diffraction image such as the image data 101, the modulator 300 emits a light beam L21 obtained by changing the traveling direction of a light beam L11 of a wavelength corresponding to the pattern among the group of light beams L1 incident thereon. The group of light beams L2 including the light beam L21 is projected on the light receiving surface of the area sensor 946. At this time, the modulator 300 having a refractive index changes the traveling direction of the light beam L11 according to Snell's law by designing the surface shape of the incident position for the light beam L11 having a single wavelength and a single approach angle incident on each point on the incident surface, and emits the light beam L21 which is a modulated light beam.

[0082] 26, the modulator 300 changes the traveling direction of the light beam so that the diffraction image of the wavelength of the light beam incident from the diffraction grating 944, which has a linear recording direction on the light receiving surface of the area sensor 946, becomes a curved line. The modulator 300 changes the traveling direction of the light beam so that the diffraction image of the first order light changes without changing the diffraction image of the zeroth order light. That is, the modulator 300 can change the diffraction images of the first order light and subsequent orders, or change the diffraction image of a specific order light.

[0083] The modulator 300 changes the traveling direction of the light beam so that the bent diffraction image fits within the light receiving surface of the area sensor 946. For example, the modulator 300 changes the traveling direction of the light beam so that the diffraction image of the first-order light becomes a curve that fits within the light receiving surface, as shown in image data 101 in FIG. 26. The modulator 300 changes the traveling direction of the light beam so that the bent diffraction image is suppressed from overlapping with other diffraction images. For example, the modulator 300 changes the traveling direction of the light beam so that multiple diffraction images of first-order light do not overlap with each other.

[0084] In this embodiment, the surface shape of the modulator 300 is designed so that a portion corresponding to the diffracted image to be bent on the light receiving surface of the area sensor 946 has a convex shape. An example of a method for designing the surface shape of the modulator 300 will be described later.

[0085] Returning to Fig. 25, an example of the operation of the spectroscopic measurement device 940A will be described. The spectroscopic measurement device 940A collects light from the measurement target 900 with an objective lens 941, converts the light into parallel light with a collimator lens 943 via a slit 942, and transmits the light through a diffraction grating 944. The spectroscopic measurement device 940A is configured to transmit the light beam transmitted through the diffraction grating 944 through a modulation lens 948 and a modulator 300, thereby changing the traveling direction of the light beam, and project the light beam onto the light receiving surface of an area sensor 946 via an imaging lens 945.

[0086] With such a configuration, the spectroscopic measurement device 940A records light of different wavelength components from different points on the measurement target 900 in different elements (pixels) on the light receiving surface of the area sensor 946. By including the modulator 300, the spectroscopic measurement device 940A can change the recording direction of the diffraction image for each wavelength from a straight line to a curved line.

[0087] 3.2 Modulator placement In the spectroscopic measurement device 940A, when the traveling direction of a light beam is changed (modulated) using the modulator 300, the installation position of the modulator 300 is important. An example of a light beam in a conventional spectroscopic measurement device not including the modulator 300 will be described with reference to Fig. 27. Fig. 27 is a diagram for explaining a light beam in a conventional spectroscopic measurement device of a snapshot type.

[0088] As shown in FIG. 27, the conventional spectroscopic measurement device includes an objective lens 941 with a focal length of f1, a collimator lens 943 with a focal length of f2, a diffraction grating 944, an imaging lens 945 with a focal length of f3, and an area sensor 946. In the conventional spectroscopic measurement device, a group of light rays LF passes through the objective lens 941. In the conventional spectroscopic measurement device, as shown in the portion PT1, there is color mixing in the diffracted light between the diffraction grating 944 and the imaging lens 945, and there is also color mixing in the light at multiple angles. For this reason, when the modulator 300 is provided between the diffraction grating 944 and the imaging lens 945, multiple light rays having different wavelengths and different incidence angles gather at one point on the incident surface, making it difficult to apply appropriate modulation. In addition, in the conventional spectroscopic measurement device, as shown in the portion PT2, there is no color mixing in the diffracted light between the imaging lens 945 and the area sensor 946, but there is color mixing in the light at multiple angles. In a conventional spectroscopic measurement device, diffracted light beams are focused at a focal point at the position of the light receiving surface of the area sensor 946, and the light beams are grouped together for each wavelength.

[0089] Therefore, in the spectroscopic measurement device 940A of the embodiment, by narrowing the range of the approach angle, the light beam incident on one point on the modulator 300 can be made to have a single wavelength and an approximately single approach angle, making it possible to apply the modulation described above.

[0090] Fig. 28 is a diagram for explaining an example of the arrangement of a spectroscopic measurement device 940A according to an embodiment. In the spectroscopic measurement device 940A, in order to collect the diffracted light beams that have passed through the diffraction grating 944 by wavelength as described above, a modulation lens 948 and a modulator 300 are arranged in the optical path OP as shown in Fig. 28. Note that the illustration of the slit 942 is omitted in Fig. 28. In the spectroscopic measurement device 940A, a modulation lens 948 having a focal length of f is arranged in the optical path OP immediately after the diffraction grating 944. M The modulation lens 948 is arranged to receive the f M A focal plane is generated at a position spaced a distance of d1 from the modulator 300. The spectroscopic measurement device 940A modulates the traveling direction of the light rays of the light beam group LF for each wavelength by disposing the modulator 300 on the focal plane of the modulation lens 938. In the spectroscopic measurement device 940A, the distance between the modulator 300 and the imaging lens 945 is d1, and the distance between the imaging lens 945 and the area sensor 946 is d2. d2 can be expressed by the following equation (6).

number

[0091] In the spectroscopic measurement device 940A, the modulator 300 performs modulation on the focal plane of the modulation lens 948, thereby obtaining the same effect as when the modulator 300 is disposed at the position of the light receiving surface of the area sensor 946 and performs modulation.

[0092] 3.3 Modulator design example Fig. 29 is a flowchart showing the procedure of the design method of the modulator 300 according to the embodiment. Fig. 30 is a diagram for explaining an example of the design method of the modulator 300 according to the embodiment. The design method shown in Fig. 29 is a design method of the modulator 300 that changes the traveling direction of the incident light beam group LF by utilizing Snell's law. The design method is executed by, for example, a computer, a dedicated electronic device, or the like. In this embodiment, the design method will be described as being executed by a computer.

[0093] In the design method shown in Fig. 29, the computer determines the focal length of the modulation lens 948 (step S101). The computer traces light rays from the modulation lens 948 to the area sensor 946 (step S102). For example, the computer traces the behavior of light rays in space from the modulation lens 948 to the area sensor 946 by executing a simulation, an application, or the like. The computer obtains a tracing result of a group of light rays LF from the modulation lens 948 to the area sensor 946, as shown by R1 in Fig. 30.

[0094] Returning to Fig. 29, the computer extracts the light ray entering the focal plane of the modulation lens 948 as the incident light ray (step S103). For example, the computer calculates the required surface normal of the modulator 300 according to Snell's law based on the incident light ray with respect to the focal plane of the modulation lens shown in Fig. 28 and the output light ray of the modulator 300 calculated from the required light ray hit position on the light receiving surface shown in R2 of Fig. 30. The light ray hit position includes, for example, a nonlinear portion shown by the dashed line in the graph shown in R3 of Fig. 30.

[0095] Returning to FIG. 29, the computer determines the outgoing light from the modulator 300 based on the required light ray hit position on the light receiving surface (step S104). The computer determines the surface normal of the modulator 300 based on the incident light ray and the outgoing light ray (step S105). The computer integrates the surface normal to determine the shape of the modulator 300 (step S106). For example, the computer determines the surface shape 310, which is one surface of the main body 301 of the modulator 300, as shown by R4 in FIG. 30. The surface shape 310 is, for example, the entrance surface of the main body 301, and has a shape in which a portion according to the nonlinearity of the light ray protrudes. The surface shape 310 may be the exit surface of the main body 301, or may be a surface shape that combines the entrance surface and exit surface of the main body 301.

[0096] 29, the computer calculates the hit position of the light beam on the light receiving surface based on the result of tracing the light beam when the modulator 300 having the determined shape is used (step S107). For example, the computer executes a simulation, an application, or the like to trace the behavior of the light beam in the space from the modulation lens 948 to the area sensor 946 when the determined modulator 300 is used.

[0097] The computer judges whether the calculated hit position coincides with the design position (step S108). The design position includes, for example, the hit position of the light beam on the designed light receiving surface when the modulator 300 is used. If the computer judges that the calculated hit position does not coincide with the design position (No in step S108), the surface shape of the modulator 300 is not suitable for the spectroscopic measurement device 940A, so the computer returns the process to step S101 already described and repeats a series of steps. If the computer judges that the calculated hit position coincides with the design position (Yes in step S108), the surface shape of the modulator 300 is suitable for the spectroscopic measurement device 940A, so the computer stores the design result in a storage device or the like and ends the steps shown in FIG. 29.

[0098] In this technology, the modulator 300 changes the traveling direction of the incident light beam by utilizing Snell's law. As shown in FIG. 29, the design method first obtains the behavior of the light beam in the space between the modulation lens 948 and the area sensor 946 by ray tracing. Next, the design method calculates the required surface normal of the modulator 300 according to Snell's law based on the incident light beam to the focal plane of the modulation lens 948 in FIG. 28 and the output light beam of the modulator 300 calculated from the required light beam hit position on the light receiving surface, such as the nonlinear point in R3 in FIG. 30. The design method finally integrates the calculated surface normal to generate the required surface shape of the modulator 300. As a result, the design method of the modulator 300 can design a surface shape 310 suitable for projecting a curved refracted image on the light receiving surface of the area sensor 946. As a result, the design method can provide a modulator 300 that can use the imaging area of ​​the area sensor 946 more efficiently and improve the wavelength resolution.

[0099] 3.4 Simulation results Next, a description will be given of a simulation result for the snapshot type spectroscopic measurement device 460 using the modulator 300 according to this embodiment. Fig. 31 is a diagram showing a simulation result for the spectroscopic measurement device 460 according to this embodiment.

[0100] In this simulation, a modulator 300 having a surface shape 310 that changes the recording direction of the diffraction layer for each wavelength of a light beam into a curve, as in the image data 102 in the left diagram of Fig. 31, is used to simulate a spectroscopic measurement device 460. The simulation shows that the result of projecting light of different wavelength components from different points of input data 510 onto the light receiving surface of an area sensor 946 via the modulator 300 is obtained as restored data 520.

[0101] The input data 510 has, for example, a pixel number of 260×260 and a wavelength of 301 nm. The restored data 520 has, for example, a pixel number of 60×60 and a wavelength of 30 nm. The restored data 520 is data restored by performing, for example, a binary matrix operation process using a modulation matrix prepared in advance. A graph 531 shows the relationship between the relative intensity of the pixel 511 in the input data 510 and the wavelength λ, and shows the true value. A graph 532 shows the relationship between the relative intensity of the pixel 521 in the restored data 520 and the wavelength λ. The graphs 531 and 532 show that the difference between the two peak values ​​is 50 nm. A comparison of the graphs 531 and 532 shows that they are similar, indicating that there is no problem in the design. In addition, the simulation result in the case where the modulator 300 is present shows that the wavelength resolution can be significantly improved compared to the case where the modulator 300 is not present.

[0102] 3.5 Actions and Effects As described above, according to this embodiment, the modulator 300 is provided between the diffraction grating 944 of the spectroscopic measurement device 940A and the area sensor 946, and can bend the diffraction image on the light receiving surface of the area sensor 946 of the light diffracted by the diffraction grating 944. This allows the modulator 300 to make the diffraction image for each wavelength of the light on the light receiving surface of the area sensor 946 larger than a linear diffraction image. As a result, the modulator 300 can use the imaging area of ​​the area sensor 946 more efficiently and improve the wavelength resolution.

[0103] The modulator 300 can change the traveling direction of the light beam so that the diffraction image of the wavelength at which the recording direction on the light receiving surface of the area sensor 946 is linear among the wavelengths of the light beam incident from the diffraction grating 944 becomes a curved line. As a result, the modulator 300 can enlarge the diffraction image of a specific wavelength, thereby further improving the wavelength resolution.

[0104] The modulator 300 can change the traveling direction of the light beam from the diffraction grating 944 so that the bent diffraction image is contained within the light receiving surface of the area sensor 946. As a result, the modulator 300 can effectively utilize the light receiving surface of the area sensor 946 without the diffraction image escaping to the outside, and therefore the wavelength resolution can be further improved.

[0105] The modulator 300 can change the traveling direction of the light beam from the diffraction grating 944 so as to suppress the overlapping of the curved diffraction image with other diffraction images on the light receiving surface of the area sensor 946. As a result, the modulator 300 can reduce the relationship between the spatial resolution and the wavelength resolution by suppressing the overlapping of the diffraction images.

[0106] The modulator 300 has an entrance surface formed in a shape of an entrance position based on the refractive index of the main body 301 and a light ray having a single wavelength and a single incident angle that is incident on one point. The one point is, for example, a point where the light ray is focused on the installation surface of the modulator 300. As a result, the modulator 300 can modulate the light ray focused on the entrance surface, thereby further improving the wavelength resolution.

[0107] By including the modulator 300, the spectroscopic measurement device 940A can bend the diffraction image on the light receiving surface of the area sensor 946 of the light beam diffracted by the diffraction grating 944. This allows the spectroscopic measurement device 940A to make the diffraction image for each wavelength of the light beam on the light receiving surface of the area sensor 946 larger than a linear diffraction image. As a result, by providing the modulator 300 in its configuration, the spectroscopic measurement device 940A can use the light receiving area of ​​the area sensor 946 more efficiently and improve the wavelength resolution.

[0108] The spectroscopic measurement device 940A can place a modulation lens 948 after the diffraction grating 44 on the optical path, and place the modulator 300 at the focal position of the modulation lens 948. As a result, the spectroscopic measurement device 940A can focus light beams similar to the light beams for each wavelength focused on the light receiving surface of the area sensor 946 on the modulator 300 by the modulation lens 948, even if the modulator 300 is not placed in the vicinity of the area sensor 946. As a result, the spectroscopic measurement device 940A can change the traveling direction of the light beams grouped by wavelength by the modulator 300, and can further improve the wavelength resolution.

[0109] 3.6 Modifications of the embodiment A spectroscopic measurement device according to a modified example of the embodiment will be described. As described above, in the conventional spectroscopic measurement device, the diffracted light beams are focused at the position of the light receiving surface of the area sensor 946, and the light beams are grouped for each wavelength. For this reason, in the modified example of the embodiment, an example of a spectroscopic measurement device 940B in which the arrangement of the modulator 300 described above is changed from that of the spectroscopic measurement device 940A will be described.

[0110] FIG. 32 is a diagram for explaining an example of the arrangement of a spectroscopic measurement device 940B according to a modified example of the embodiment. As shown in FIG. 32, the spectroscopic measurement device 940B is a snapshot type device, similar to the above-mentioned spectroscopic measurement device 940A. The spectroscopic measurement device 940B includes an objective lens 941 with a focal length of f1, a collimator lens 943 with a focal length of f2, a diffraction grating 944, an imaging lens 945 with a focal length of f3, a modulator 300, and an area sensor 946. That is, the spectroscopic measurement device 940B does not include the modulation lens 948 of the above-mentioned spectroscopic measurement device 940A, and therefore the configuration can be simplified.

[0111] The modulator 300 is disposed on the light receiving surface side of the area sensor 946 so as to be located on the focal plane of the imaging lens 945. For example, the modulator 300 can be disposed on the light receiving surface of the area sensor 946 or in the vicinity of the light receiving surface.

[0112] The modulator 300 receives light beams (diffracted light beams) grouped by wavelength from the imaging lens 945 toward the area sensor 946. The modulator 300 is configured to change the traveling direction of the incident light beams according to Snell's law. The modulator 300 changes the traveling direction of the light beams emitted toward the area sensor 946 so that the recording direction of the diffraction image of the light beams for each wavelength on the light receiving surface of the area sensor 946 is curved. In other words, the modulator 300 changes the traveling direction of the light beams so that the recording direction of the diffraction image on the light receiving surface of the area sensor 946 is curved.

[0113] Next, an example of the operation of the spectroscopic measurement device 940B will be described. The spectroscopic measurement device 940B collects light from the measurement target 900 with an objective lens 941, converts the light into parallel light with a collimator lens 943 via a slit 942, and transmits the light through a diffraction grating 944. The spectroscopic measurement device 940B forms an image of the light beam transmitted through the diffraction grating 944 with an imaging lens 945, and collects the light on the modulator 300. The spectroscopic measurement device 940B transmits the light beam through the modulator 300, and projects the light beam, whose traveling direction has been changed, onto the light receiving surface of an area sensor 946.

[0114] With this configuration, the spectroscopic measurement device 940B records light of different wavelength components from different points on the measurement target 900 in different elements (pixels) on the light receiving surface of the area sensor 946. Even if the modulator 300 is disposed on the light receiving surface side of the area sensor 946, the spectroscopic measurement device 940B can change the recording direction of the diffraction image for each wavelength from a straight line to a curved line, as with the spectroscopic measurement device 940A described above. In addition, the spectroscopic measurement device 940B does not need to use the modulation lens 948 described above by disposing the modulator 300 on the light receiving surface side of the area sensor 946 so as to be located on the focal plane of the imaging lens 945. For this reason, the spectroscopic measurement device 940B can have a simpler device configuration than the spectroscopic measurement device 940A.

[0115] 3.7 Modulator design example according to the modified embodiment Fig. 33 is a flowchart showing the steps of a design method for a modulator 300 according to a modified example of the embodiment. The design method shown in Fig. 33 is a modification of the design method shown in Fig. 29 above.

[0116] 33, the computer traces light rays from the imaging lens 945 to the area sensor 946 (step S111). For example, the computer traces the behavior of light rays in space from the imaging lens 945 to the area sensor 946 by executing a simulation, an application, or the like.

[0117] The computer extracts the light beam entering the focal plane of the imaging lens 945 as the incident light beam (step S112). For example, the computer calculates the required surface normal of the modulator 300 according to Snell's law based on the incident light beam on the focal plane of the imaging lens 945 and the output light beam of the modulator 300 calculated from the required light beam hit position on the light receiving surface of the area sensor 946.

[0118] The computer determines the output light from the modulator 300 based on the required light ray hit position on the light receiving surface (step S104). The computer determines the surface normal of the modulator 300 based on the incident light ray and the output light ray (step S105). The computer integrates the surface normal to determine the shape of the modulator 300 (step S106). The computer stores the design result of determining the shape of the modulator 300 in a storage device or the like, and ends the procedure shown in FIG.

[0119] In the procedure of the design method shown in Fig. 33, the spectroscopic measurement device 940B does not include the modulation lens 948, so the procedure of step S101 shown in Fig. 29 can be eliminated. Also, in the procedure of the design method shown in Fig. 33, the spectroscopic measurement device 940B places the modulator 300 in the vicinity of the light receiving surface of the area sensor 946, so that the procedure of steps S107 to S108 shown in Fig. 29 can be eliminated. As a result, the procedure of the design method shown in Fig. 33 can be simplified compared to the design method shown in Fig. 29.

[0120] In this technology, the modulator 300 changes the traveling direction of the incident light ray by utilizing Snell's law. In the design method, first, the behavior of the light ray in the space between the imaging lens 945 and the area sensor 946 is obtained by ray tracing. Next, in the design method, the required surface normal of the modulator 300 is calculated according to Snell's law based on the incident light ray with respect to the focal plane of the imaging lens 945 and the output light ray of the modulator 300 calculated from the required light ray hit position on the light receiving surface of the area sensor 946. Finally, in the design method, the calculated surface normal is integrated to generate the required surface shape of the modulator 300. In this way, the design method of the modulator 300 can design a surface shape 310 suitable for projecting a curved refracted image on the light receiving surface of the area sensor 946. As a result, the design method can provide the modulator 300 that can use the imaging area of ​​the area sensor 946 more efficiently and improve the wavelength resolution.

[0121] 3.8 Mobile application examples The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of moving body such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility device, an airplane, a drone, a ship, a robot, etc.

[0122] FIG. 34 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a moving object control system to which the technology according to the present disclosure can be applied.

[0123] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 34, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also, as functional configurations of the integrated control unit 12050, a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (Interface) 12053 are illustrated.

[0124] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0125] The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as head lamps, back lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves or signals of various switches transmitted from a portable device that replaces a key may be input to the body system control unit 12020. The body system control unit 12020 receives the input of these radio waves or signals and controls the door lock device, power window device, lamps, and the like of the vehicle.

[0126] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture an image outside the vehicle and receives the captured image. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for a person, a car, an obstacle, a sign, or characters on a road surface, based on the received image.

[0127] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal according to the amount of light received. The imaging unit 12031 can output the electrical signal as an image, or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0128] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing.

[0129] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, the steering mechanism, or the braking device based on the information inside and outside the vehicle acquired by the outside-of-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output a control command to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc.

[0130] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on the driver's operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle acquired by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0131] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside-vehicle information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside-vehicle information detection unit 12030, and perform cooperative control for the purpose of preventing glare, such as switching from high beams to low beams.

[0132] The audio / video output unit 12052 transmits at least one output signal of audio and video to an output device capable of visually or audibly notifying information to passengers in the vehicle or the outside of the vehicle. In the example of Fig. 34, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are exemplified as the output device. The display unit 12062 may include at least one of an on-board display and a head-up display, for example.

[0133] FIG. 35 is a diagram showing an example of the installation position of the imaging unit 12031.

[0134] In FIG. 35, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0135] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided at positions such as the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield in the vehicle interior of the vehicle 12100. The imaging unit 12101 provided at the front nose and the imaging unit 12105 provided at the upper part of the windshield in the vehicle interior mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided at the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided at the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 provided at the upper part of the windshield in the vehicle interior is mainly used to detect a preceding vehicle, a pedestrian, an obstacle, a traffic light, a traffic sign, a lane, or the like.

[0136] 35 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, an overhead image of the vehicle 12100 viewed from above is obtained by superimposing the image data captured by the imaging units 12101 to 12104.

[0137] At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera made up of a plurality of imaging elements, or may be an imaging element having pixels for detecting a phase difference.

[0138] For example, the microcomputer 12051 can extract, as a preceding vehicle, a three-dimensional object that is the closest three-dimensional object on the travel path of the vehicle 12100 and travels at a predetermined speed (for example, 0 km / h or more) in approximately the same direction as the vehicle 12100, by calculating the distance to each three-dimensional object in the imaging ranges 12111 to 12114 and the change over time of this distance (relative speed with respect to the vehicle 12100) based on the distance information obtained from the imaging units 12101 to 12104. Furthermore, the microcomputer 12051 can set a vehicle distance to be secured in advance in front of the preceding vehicle, and perform automatic brake control (including follow-up stop control) and automatic acceleration control (including follow-up start control). In this way, cooperative control can be performed for the purpose of automatic driving that travels autonomously without relying on the driver's operation.

[0139] For example, the microcomputer 12051 classifies and extracts three-dimensional object data on three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. Then, the microcomputer 12051 determines a collision risk indicating the risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

[0140] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether or not a pedestrian is present in the captured images of the imaging units 12101 to 12104. The recognition of such a pedestrian is performed, for example, by a procedure of extracting feature points in the captured images of the imaging units 12101 to 12104 as infrared cameras, and a procedure of performing pattern matching processing on a series of feature points that indicate the contour of an object to determine whether or not the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the captured images of the imaging units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating a pedestrian at a desired position.

[0141] An example of a vehicle control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the imaging unit 12031 and the like among the configurations described above. Specifically, the spectroscopic measurement device 940A can be applied to the imaging unit 12031 and the like. By applying the technology according to the present disclosure to the imaging unit 12031, it is possible to improve the wavelength resolution, and therefore the detection accuracy of information outside the vehicle can be improved.

[0142] 3.9 Application example to endoscopic surgery system The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

[0143] FIG. 36 is a diagram showing an example of a schematic configuration of an endoscopic surgery system to which the technology according to the present disclosure (the present technology) can be applied.

[0144] 36 shows a state in which an operator (doctor) 11131 is performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgery system 11000. As shown in the figure, the endoscopic surgery system 11000 is composed of an endoscope 11100, other surgical tools 11110 such as an insufflation tube 11111 and an energy treatment tool 11112, a support arm device 11120 that supports the endoscope 11100, and a cart 11200 on which various devices for endoscopic surgery are mounted.

[0145] The endoscope 11100 is composed of a lens barrel 11101, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 11132, and a camera head 11102 connected to the base end of the lens barrel 11101. In the illustrated example, the endoscope 11100 is configured as a so-called rigid scope having a rigid lens barrel 11101, but the endoscope 11100 may be configured as a so-called flexible scope having a flexible lens barrel.

[0146] An opening into which an objective lens is fitted is provided at the tip of the lens barrel 11101. A light source device 11203 is connected to the endoscope 11100, and light generated by the light source device 11203 is guided to the tip of the lens barrel by a light guide extending inside the lens barrel 11101, and is irradiated via the objective lens toward an observation target in the body cavity of the patient 11132. The endoscope 11100 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0147] An optical system and an image sensor are provided inside the camera head 11102, and reflected light (observation light) from an observation target is collected on the image sensor by the optical system. The observation light is photoelectrically converted by the image sensor to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to an observation image. The image signal is transmitted to a camera control unit (CCU) 11201 as RAW data.

[0148] The CCU 11201 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and performs overall control of the operations of the endoscope 11100 and the display device 11202. Furthermore, the CCU 11201 receives an image signal from the camera head 11102, and performs various types of image processing on the image signal, such as development processing (demosaic processing), for displaying an image based on the image signal.

[0149] Under the control of the CCU 11201, the display device 11202 displays an image based on an image signal that has been subjected to image processing by the CCU 11201.

[0150] The light source device 11203 is composed of a light source such as an LED (light emitting diode), and supplies the endoscope 11100 with irradiation light when photographing an operation site or the like.

[0151] The input device 11204 is an input interface for the endoscopic surgery system 11000. A user can input various information and instructions to the endoscopic surgery system 11000 via the input device 11204. For example, the user inputs an instruction to change the imaging conditions (type of irradiated light, magnification, focal length, etc.) of the endoscope 11100.

[0152] The treatment tool control device 11205 controls the driving of the energy treatment tool 11112 for cauterizing tissue, incising, sealing blood vessels, etc. The insufflation device 11206 sends gas into the body cavity of the patient 11132 via the insufflation tube 11111 to inflate the body cavity for the purpose of securing the field of view of the endoscope 11100 and securing the working space of the surgeon. The recorder 11207 is a device capable of recording various information related to the surgery. The printer 11208 is a device capable of printing various information related to the surgery in various formats such as text, image, or graph.

[0153] The light source device 11203 that supplies irradiation light to the endoscope 11100 when photographing the surgical site can be composed of a white light source composed of, for example, an LED, a laser light source, or a combination of these. When the white light source is composed of a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, so that the white balance of the captured image can be adjusted in the light source device 11203. In this case, it is also possible to capture images corresponding to each of the RGB colors in a time-division manner by irradiating the observation object with laser light from each of the RGB laser light sources in a time-division manner and controlling the driving of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter to the image sensor.

[0154] The light source device 11203 may be controlled to change the intensity of the light it outputs at predetermined time intervals. The driving of the image sensor of the camera head 11102 may be controlled in synchronization with the timing of the change in the light intensity to obtain images in a time-division manner, and the images may be synthesized to generate an image with a high dynamic range that is free of so-called blackout and whiteout.

[0155] The light source device 11203 may be configured to supply light of a predetermined wavelength band corresponding to the special light observation. In the special light observation, for example, by utilizing the wavelength dependency of light absorption in body tissue, a narrow band light is irradiated compared to the irradiated light (i.e., white light) during normal observation, and a predetermined tissue such as blood vessels on the mucous membrane surface is photographed with high contrast, so-called narrow band imaging is performed. Alternatively, in the special light observation, a fluorescent observation may be performed in which an image is obtained by fluorescence generated by irradiating an excitation light. In the fluorescent observation, it is possible to irradiate an excitation light to a body tissue and observe the fluorescence from the body tissue (autofluorescence observation), or to locally inject a reagent such as indocyanine green (ICG) into the body tissue and irradiate the body tissue with excitation light corresponding to the fluorescent wavelength of the reagent to obtain a fluorescent image. The light source device 11203 may be configured to supply narrow band light and / or excitation light corresponding to such special light observation.

[0156] FIG. 37 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0157] The camera head 11102 has a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 has a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other by a transmission cable 11400 so as to be able to communicate with each other.

[0158] The lens unit 11401 is an optical system provided at the connection portion with the lens barrel 11101. Observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and enters the lens unit 11401. The lens unit 11401 is configured by combining a plurality of lenses including a zoom lens and a focus lens.

[0159] The imaging unit 11402 may include one imaging element (so-called single-plate type) or multiple imaging elements (so-called multiple-plate type). When the imaging unit 11402 is configured as a multiple-plate type, for example, each imaging element may generate an image signal corresponding to each of RGB, and a color image may be obtained by combining the image signals. Alternatively, the imaging unit 11402 may be configured to have a pair of imaging elements for acquiring image signals for the right eye and the left eye corresponding to a 3D (dimensional) display. By performing a 3D display, the surgeon 11131 can more accurately grasp the depth of the biological tissue in the surgical site. Note that when the imaging unit 11402 is configured as a multiple-plate type, the lens unit 11401 may also be provided in multiple systems corresponding to each imaging element.

[0160] Furthermore, the imaging unit 11402 does not necessarily have to be provided in the camera head 11102. For example, the imaging unit 11402 may be provided inside the lens barrel 11101, immediately behind the objective lens.

[0161] The driving unit 11403 is configured by an actuator, and moves the zoom lens and focus lens of the lens unit 11401 by a predetermined distance along the optical axis under the control of the camera head control unit 11405. This allows the magnification and focus of the image captured by the imaging unit 11402 to be appropriately adjusted.

[0162] The communication unit 11404 is configured by a communication device for transmitting and receiving various information to and from the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 to the CCU 11201 via the transmission cable 11400 as RAW data.

[0163] Furthermore, the communication unit 11404 receives a control signal for controlling the driving of the camera head 11102 from the CCU 11201, and supplies the control signal to the camera head control unit 11405. The control signal includes information on the imaging conditions, such as information specifying the frame rate of the captured image, information specifying the exposure value at the time of capturing the image, and / or information specifying the magnification and focus of the captured image.

[0164] The image capturing conditions such as the frame rate, exposure value, magnification, and focus may be appropriately specified by a user, or may be automatically set by the control unit 11413 of the CCU 11201 based on an acquired image signal. In the latter case, the endoscope 11100 is equipped with a so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

[0165] The camera head control unit 11405 controls the driving of the camera head 11102 based on a control signal received from the CCU 11201 via the communication unit 11404.

[0166] The communication unit 11411 is configured with a communication device for transmitting and receiving various information to and from the camera head 11102. The communication unit 11411 receives an image signal transmitted from the camera head 11102 via the transmission cable 11400.

[0167] Furthermore, the communication unit 11411 transmits, to the camera head 11102, a control signal for controlling the driving of the camera head 11102. The image signal and the control signal can be transmitted by electrical communication, optical communication, or the like.

[0168] The image processing unit 11412 performs various types of image processing on the image signal, which is RAW data sent from the camera head 11102 .

[0169] The control unit 11413 performs various controls related to imaging of the surgical site etc. by the endoscope 11100 and display of the captured image obtained by imaging the surgical site etc. For example, the control unit 11413 generates a control signal for controlling the driving of the camera head 11102.

[0170] Further, the control unit 11413 causes the display device 11202 to display the captured image showing the surgical site, etc., based on the image signal that has been image-processed by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition techniques. For example, the control unit 11413 can recognize surgical tools such as forceps, specific living body parts, bleeding, mist when the energy treatment tool 11112 is used, etc., by detecting the shape and color of the edge of an object included in the captured image. When the control unit 11413 causes the display device 11202 to display the captured image, it may use the recognition result to superimpose various types of surgery support information on the image of the surgical site. By superimposing and presenting the surgery support information to the surgeon 11131, the burden on the surgeon 11131 can be reduced and the surgeon 11131 can proceed with the surgery reliably.

[0171] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable for communication of electrical signals, an optical fiber for optical communication, or a composite cable of these.

[0172] Here, in the illustrated example, communication is performed wired using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may also be performed wirelessly.

[0173] An example of an endoscopic surgery system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the imaging unit 11402 among the configurations described above. By applying the technology according to the present disclosure to the imaging unit 11402, a clearer image of the surgical site can be obtained, allowing the surgeon to reliably check the surgical site.

[0174] Although an endoscopic surgery system has been described here as an example, the technology disclosed herein may also be applied to other systems, such as a microsurgery system.

[0175] Although the embodiments of the present disclosure have been described above, the technical scope of the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present disclosure. In addition, components of different embodiments and modifications may be appropriately combined.

[0176] Furthermore, the effects of each embodiment described in this specification are merely examples and are not limiting, and other effects may also be provided.

[0177] Furthermore, each of the above-described embodiments may be used alone or in combination with other embodiments.

[0178] In the above embodiment, the modulator 300 is described as bending the recording direction of the diffraction image in a curved shape, but is not limited thereto. For example, the modulator 300 can bend the recording direction of the diffraction image partially, bend it in a different direction, or bend it in a zigzag shape.

[0179] The present technology can also be configured as follows. (1) A modulator provided between a diffraction grating and an image sensor, A light beam is incident on the image sensor from the diffraction grating, and the traveling direction of the light beam emitted toward the image sensor is changed so that the recording direction of a diffraction image for each wavelength of the light beam on the light receiving surface of the image sensor is curved. Modulator. (2) The traveling direction of the light beam incident from the diffraction grating is changed so that the diffraction image of the wavelength at which the recording direction on the light receiving surface is linear is curved. The modulator according to (1) above. (3) The traveling direction of the light beam is changed so that the bent diffraction image is contained within the light receiving surface. The modulator according to (1) or (2). (4) The traveling direction of the light beam is changed so as to suppress superposition of the bent diffraction image with other diffraction images. A modulator according to any one of (1) to (3). (5) a body formed by a permeable member; The body has an entrance surface formed in a shape of an entrance position based on the refractive index of the transparent member and the light ray having a single wavelength and a single angle of incidence incident on a single point. A modulator according to any one of (1) to (4). (6) A diffraction grating; an image sensor having the diffraction grating disposed on a light receiving surface side; a modulator disposed between the diffraction grating and the image sensor; Equipped with The modulator comprises: A light beam is incident on the image sensor from the diffraction grating, and the traveling direction of the light beam emitted toward the image sensor is changed so that the recording direction of a diffraction image for each wavelength of the light beam on the light receiving surface of the image sensor is curved. Imaging device. (7) a modulation lens disposed between the diffraction grating and the modulator; The modulator is disposed at the focal position of the modulation lens. The imaging device according to (6) above. (8) an imaging lens disposed between the modulator and the image sensor; The imaging lens forms an image of the light beam emitted by the modulator on the light receiving surface. The imaging device according to (6) or (7) above. (9) an imaging lens disposed between the diffraction grating and the image sensor; The modulator is disposed on the light receiving surface side of the image sensor so as to be located on the focal plane of the imaging lens. The imaging device according to (6) above. (10) A method for designing a modulator that changes the direction of a light beam incident on a diffraction grating and outputs the light beam to an image sensor, comprising the steps of: Tracking the spatial behavior of the input and output rays of the modulator; determining a surface normal of a modulator based on the incident light ray and the exiting light ray; integrating the surface normal to determine a shape of the modulator; A design method including: [Explanation of symbols]

[0180] 300 Modulator 900 Measurement targets 901, 913 Prism 911 light source 912, 932, 942 Slit 914 Linear Sensor 921 Wavelength Filter Array 922, 947 Optical Filters 923, 936, 946 Area Sensor 931, 941 Objective Lenses 933, 943 Collimating Lens 934 Spectroscopic element 940, 940A, 940B Spectroscopic Instruments 944 Diffraction Grating Spectroscopic Element (Diffraction Grating) 935, 945 Imaging Lens 948 Modulation Lens

Claims

1. A modulator provided between a diffraction grating and an image sensor, A light beam is incident on the image sensor from the diffraction grating, and the traveling direction of the light beam emitted toward the image sensor is changed so that a diffraction image for each wavelength of the light beam projected on the light receiving surface of the image sensor is curved. Modulator.

2. The traveling direction of the light beam incident from the diffraction grating is changed so that the diffraction image of the wavelength at which the diffraction image on the light receiving surface is linear is curved.

2. The modulator of claim 1.

3. The traveling direction of the light beam is changed so that the bent diffraction image is contained within the light receiving surface.

3. The modulator of claim 2.

4. The traveling direction of the light beam is changed so as to suppress superposition of the bent diffraction image with other diffraction images. The modulator of claim 3.

5. a body formed by a permeable member; The body has an entrance surface formed in a shape of an entrance position based on the refractive index of the transparent member and the light ray having a single wavelength and a single angle of incidence incident on a single point.

5. The modulator of claim 4.

6. A diffraction grating; an image sensor having the diffraction grating disposed on a light receiving surface side; a modulator disposed between the diffraction grating and the image sensor; Equipped with The modulator comprises: A light beam is incident on the image sensor from the diffraction grating, and the traveling direction of the light beam emitted toward the image sensor is changed so that a diffraction image for each wavelength of the light beam projected on the light receiving surface of the image sensor is curved. Imaging device.

7. a modulation lens disposed between the diffraction grating and the modulator; The modulator is disposed at the focal position of the modulation lens. The imaging device according to claim 6.

8. an imaging lens disposed between the modulator and the image sensor; The imaging lens forms an image of the light beam emitted by the modulator on the light receiving surface. The imaging device according to claim 7.

9. an imaging lens disposed between the diffraction grating and the image sensor; The modulator is disposed on the light receiving surface side of the image sensor so as to be located on the focal plane of the imaging lens. The imaging device according to claim 6.

Images