Optical devices, optical systems

Abstract

To improve the optical properties of optical devices. [Solution] An optical device comprising a first light-receiving unit having a first group of reflective surfaces, a second light-receiving unit having a second group of reflective surfaces, and a support that supports the first and second light-receiving units, wherein with respect to a first virtual plane, a second virtual plane, and a third virtual plane between the first and second virtual planes that are perpendicular to the optical axis and intersect the support, the first light-receiving unit is located between the third virtual plane and the second virtual plane, and the second light-receiving unit is located between the first and third virtual planes, the first group of reflective surfaces reflects light incident through the first virtual plane in multiple directions nonparallel to the optical axis, the second group of reflective surfaces reflects the light reflected by the first group of reflective surfaces, the light reflected by the second group of reflective surfaces exits through the second virtual plane, the first light-receiving unit has an incident surface separate from the first group of reflective surfaces to which light incident through the first virtual plane enters, and at least a portion of the incident light does not exit through the second virtual plane.

Description

Technical Field

[0001] The present invention relates to an optical device usable in various fields such as astronomical observation and material analysis. Background Art

[0002] Conventionally, in various fields such as astronomical observation and material analysis, optical devices that split light into individual wavelengths, receive the split light with a detector, and measure light intensity have been used. In the field of astronomical observation, an observation method called integral field spectrography, which enables simultaneous observation of two-dimensional spatial information and spectral information, is known. As optical systems used to implement integral field spectrography, microlens array type, fiber bundle type, image slicer type, etc. are known.

[0003] It is known that although the image slicer type does not have a simple optical system configuration, it has little loss of spatial information and provides high spatial resolution even in a narrow field of view. In the image slicer type, an integral field spectroscopy system is configured by combining a slice mirror, a pupil mirror and other components. The slice mirror is a mirror that splits the focal plane image of a telescope into a plurality of elongated images. The pupil mirror is a mirror for rearranging the images split by the slice mirror in one dimension.

[0004] In an image slicer type optical device, observation light incident on the slice mirror is reflected in mutually different directions as a plurality of split light beams by the plurality of reflecting surfaces of the slice mirror. Each of the plurality of light beams is guided to different light-receiving regions of an optical sensor via a pupil mirror or the like.

[0005] Patent Document 1 describes an integral field optical device provided with a slice mirror. Fig. 12(a) is a plan view of the slice mirror described in Patent Document 1, and Fig. 12(b) is a perspective view thereof. The slice mirror includes a plurality of rectangular reflecting surfaces 2a. In order to split incident observation light and reflect the split light in different directions, each of the reflecting surfaces 2a included in the slice mirror faces a different direction from the others. Prior Art Documents [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-96461 [Overview of the project] [Problems that the invention aims to solve]

[0007] The inventors of this invention aimed to improve the spatial or frequency resolution in surface spectroscopy in a surface spectroscopy system using an image slicer type optical device.

[0008] In this context, the inventors discovered that there is room for improvement in the optical properties of optical devices. [Means for solving the problem]

[0009] This disclosure aims to provide a technology that is advantageous for improving the optical properties of optical devices.

[0010] A first aspect of the present disclosure is an optical device comprising: a first light-receiving unit having a first group of reflective surfaces; a second light-receiving unit having a second group of reflective surfaces; and a support supporting the first light-receiving unit and the second light-receiving unit, wherein the first light-receiving unit is located between the third virtual plane and the second virtual plane with respect to a first virtual plane perpendicular to the optical axis of the optical device and intersecting the support; a second virtual plane perpendicular to the optical axis and intersecting the support; and a third virtual plane perpendicular to the optical axis and between the first virtual plane and the second virtual plane, and the second light-receiving unit is located between the first virtual plane and the third virtual plane. The optical device is positioned between a plane and a virtual plane, the first group of reflective surfaces reflects light incident through the first virtual plane in multiple different directions that are not parallel to the optical axis, the second group of reflective surfaces reflects the light reflected by the first group of reflective surfaces, the light reflected by the second group of reflective surfaces exits through the second virtual plane, and the first light receiving unit has an incident surface into which the light incident through the first virtual plane enters, separate from the first group of reflective surfaces, and has a structure in which at least a portion of the light incident on the incident surface does not exit through the second virtual plane.

[0011] A second aspect of the present disclosure is an optical device comprising: a first light-receiving unit having a first group of reflective surfaces; a second light-receiving unit having a second group of reflective surfaces; and a support that supports the first light-receiving unit and the second light-receiving unit, wherein the first light-receiving unit is located between the third virtual plane and the second virtual plane with respect to a first virtual plane perpendicular to the optical axis of the optical device and intersecting the support; a second virtual plane perpendicular to the optical axis and intersecting the support; and a third virtual plane perpendicular to the optical axis and between the first virtual plane and the second virtual plane, and the second light-receiving unit is located between the first virtual plane and the third virtual plane, and the first group of reflective surfaces However, the optical device has a structure in which light incident through the first virtual plane is reflected in multiple different directions that are not parallel to the optical axis, the second group of reflective surfaces reflects the light reflected by the first group of reflective surfaces, the light reflected by the second group of reflective surfaces exits through the second virtual plane, and the first light receiving unit has an incident surface into which the light incident through the first virtual plane is incident, separate from the first group of reflective surfaces, and at least a portion of the light incident on the incident surface is reflected by the incident surface and incident on the portion of the support located between the second virtual plane and the third virtual plane. [Effects of the Invention]

[0012] This disclosure provides a technology that is advantageous for improving the optical properties of optical devices. [Brief explanation of the drawing]

[0013] [Figure 1] A diagram illustrating the overall configuration of the optical system according to Embodiment 1. [Figure 2] (a) A schematic cross-sectional view of the surface spectroscopy unit 21 cut along the YZ plane. (b) An enlarged view of the area enclosed by the dotted line A1 in Figure 2(a). [Figure 3] An exploded perspective view illustrating the structure of the surface spectroscopy unit. [Figure 4] A plan view of the incident side member 2, seen from the exit side member 4 along the Z-plus direction. [Figure 5](a) is a plan view of the emission-side member 4 as viewed from the incident-side member side along the negative Z direction. (b) is an enlarged plan view illustrating the slice mirror 1 in an enlarged manner. [Figure 6] is a perspective view where the incident-side member 2 is removed from the surface spectroscopy unit 21 to make the inner surface of the intermediate member 3 easily visible. [Figure 7] is a schematic cross-sectional view showing the surface spectroscopy unit 21 as an example of Embodiment 2. [Figure 8] (a) is a perspective view showing the appearance of an emission-side member 4A according to Embodiment 3. (b) is an exploded perspective view of the emission-side member 4A according to Embodiment 3. [Figure 9] is a perspective view of an emission-side member 4C according to Embodiment 4. [Figure 10] (a) is a front view of the emission-side member 4C according to Embodiment 4. (b) is an enlarged view of a region A2 surrounded by a dotted line in FIG. 10(a). [Figure 11] (a) is a schematic cross-sectional view of a surface spectroscopy unit 21C according to Embodiment 4 cut along the YZ plane. (b) is an enlarged view of a portion A3 surrounded by a dotted line in FIG. 11(a). [Figure 12] (a) is a plan view of a slice mirror. (b) is a perspective view of the slice mirror. [Figure 13] is a diagram illustrating the configuration of a surface spectroscopy unit by way of example. MODE FOR CARRYING OUT THE INVENTION

[0014] Optical components, optical systems, optical devices and the like according to embodiments of the present invention will be described with reference to the drawings. The embodiments shown below are illustrative, and for example, those skilled in the art can appropriately modify and implement detailed configurations without departing from the spirit of the present invention.

[0015] In the drawings referred to in the following description of the embodiments, unless otherwise specified, elements denoted by the same reference signs have similar functions. In the drawings, when a plurality of identical elements are arranged, the assignment of reference signs and the description thereof may be omitted.

[0016] In addition, since the drawings may be schematically represented for the convenience of illustration and description, it shall be understood that the shapes, sizes, arrangements and other features of the elements described in the drawings do not necessarily strictly coincide with those of actual objects. In addition, unless otherwise specified, the descriptions of "not less than XX and not more than YY" and "XX to YY" representing a numerical range mean a numerical range including the endpoints XX (lower limit) and YY (upper limit). When numerical ranges are described stepwise, the upper and lower limits of each numerical range can be combined arbitrarily.

[0017] In the following description, to clarify the positional relationship, mutually orthogonal X-axis direction, Y-axis direction and Z-axis direction are defined. For example, when described as the positive X direction, it refers to the same direction as that indicated by the X-axis arrow in the illustrated orthogonal coordinate system; when described as the negative X direction, it refers to the direction 180 degrees opposite to the direction indicated by the X-axis arrow in the illustrated orthogonal coordinate system. In addition, when simply described as the X direction, it refers to a direction parallel to the X-axis regardless of whether it is the same as the direction indicated by the illustrated X-axis arrow. The same applies to directions other than the X direction.

[0018] [Embodiment 1] An optical component, an optical system, an optical device, etc. according to Embodiment 1 will be described. With reference to Fig. 1, the overall configuration of an optical system (imaging spectroscopic system) according to Embodiment 1 will be described. The imaging spectroscopic system includes an image slicer type imaging spectroscopic unit 21, a two-dimensional photosensor 28 that images light emitted from the imaging spectroscopic unit 21, and an information processing device 100. The imaging spectroscopic unit 21 includes an entrance slit 24 as an input section, a slice mirror 1 as a first light receiving section, a second reflecting surface group 26 as a second light receiving section, and an exit slit array 27.

[0019] The optical sensor 28 is an imaging device equipped with a two-dimensional light-receiving surface that is sensitive to the wavelength band of the incident light 23, and transmits the detection result (measurement result) from the optical sensor 28 to the information processing device 100. The information processing device 100 is a computer that performs information processing related to surface spectroscopy based on the detection result of the optical sensor 28, and calculates two-dimensional spatial information and spectral information about the incident light 23 based on the measurement result of the optical sensor 28. When the optical sensor 28 captures a video, the information processing device 100 can also acquire the time-dependent changes in the two-dimensional spatial information and spectral information.

[0020] The surface spectroscopy unit 21, as an optical device, is preferably used for astronomical observation, but can be used for various applications including civilian and industrial use. When used for astronomical observation, incident light 23 from a telescope (not shown) enters the surface spectroscopy unit 21 through the incident slit 24, which serves as the incident part, and the incident light 23 travels in a predetermined direction, the Z-minus direction, to reach the slice mirror 1 (first member). Note that, not limited to Figure 1, the incident light 23 may be shown as parallel light for illustrative purposes, but the incident light 23 is not necessarily limited to parallel light. The optical axis of the incident light 23 is defined as optical axis OA. The incident slit 24 may be an aperture or a filter (window) that transmits light in the wavelength range of the object to be observed. As will be described later, the positional relationship between the incident slit 24 and the slice mirror is set so that the incident light 23 transmitted through the incident slit 24 illuminates an area slightly wider than the area where the segmented mirrors of the slice mirror 1 are arranged.

[0021] For the convenience of explaining the positional relationships of each component, Figure 1 shows the first virtual plane IP1, the second virtual plane IP2, the third virtual plane IP3, and the fourth virtual plane IP4. The first virtual plane IP1, the second virtual plane IP2, and the third virtual plane IP3 are virtual planes perpendicular to the optical axis OA of the incident light 23 and intersecting the support SP, and are arranged in the order of the first virtual plane IP1, the third virtual plane IP3, and the second virtual plane IP2 from left to right in the figure. That is, they are arranged in the order of the first virtual plane IP1, the third virtual plane IP3, and the second virtual plane IP2 along the incident direction (Z-minus direction) of the incident light 23.

[0022] The slice mirror 1 has a first group of reflective surfaces. The normal directions of the multiple reflective surfaces constituting the first group of reflective surfaces are different from each other, and also different from the direction of the optical axis OA (optical axis direction). The focal plane image of the telescope is divided into multiple sub-images by the slice mirror 1, which is an optical element, and the light beam of each sub-image is reflected in a different direction. For ease of illustration, only four reflected rays, reflected light 25-1, reflected light 25-2, reflected light 25-3, and reflected light 25-4, are schematically shown in Figure 1. However, the slice mirror 1 is configured to divide the incident light 23 into a larger number of sub-images, and a number of mirrors corresponding to the number of divisions are arranged in the second group of reflective surfaces 26.

[0023] The mirror array has a second reflective surface group 26. The normal directions of the multiple reflective surfaces constituting the second reflective surface group 26 are different from each other and also different from the direction of the optical axis OA (optical axis direction). The reflected light rays (reflected light beams) corresponding to each partial image are reflected by each mirror surface constituting the second reflective surface group 26, pass through the output slit array 27, and the light that has passed through the fourth virtual plane IP4 is guided to the light sensor 28. Each mirror of the second reflective surface group 26 collimates each light beam reflected by the slice mirror 1 in the Z-minus direction, but the mirror surface may be curved or flat. The output slit array 27 may be located, for example, in the housing of the surface spectroscopy unit 21, or in a support member that supports the slice mirror 1, or in a structural member arranged within the surface spectroscopy unit 21. The fourth virtual plane IP4 may be a plane parallel to the light-receiving surface of the light sensor 28. Also, the fourth virtual plane IP4 may be perpendicular to the optical axis OA. Here, we have described a configuration in which the fourth virtual plane IP4 is perpendicular to the optical axis OA and parallel to the second virtual plane IP2. However, a bent optical system can also be provided between the second virtual plane IP2 and the fourth virtual plane IP4 facing the optical sensor 28. In that case, the fourth virtual plane IP4 does not need to be perpendicular to the optical axis OA, and the second virtual plane IP2 and the fourth virtual plane IP4 can intersect.

[0024] A slice mirror 1, equipped with a first group of reflective surfaces as a first light-receiving section, is located between a third virtual plane IP3 and a second virtual plane IP2, and a second group of reflective surfaces 26, as a second light-receiving section, is located between a first virtual plane IP1 and a third virtual plane IP3. The first group of reflective surfaces of the slice mirror 1 reflects light incident through the first virtual plane IP1 in multiple different directions nonparallel to the optical axis OA, and the second group of reflective surfaces 26 reflects the light reflected by the first group of reflective surfaces. The light reflected by the second group of reflective surfaces 26 exits through the second virtual plane IP2. In this way, at least a portion (preferably 50% or more, more preferably 75% or more, and even more preferably 90% or more) of the light incident on the first group of reflective surfaces exits through the second virtual plane IP2.

[0025] Furthermore, a diffraction grating DIF may be placed between the second reflective surface group 26 and the optical sensor 28 as a spectral section to spectrally separate the light beam of each partial image according to its wavelength. In addition, a focusing lens LA (lens array) may be placed between the diffraction grating DIF and the optical sensor 28 to focus the partial images spectrally separated according to their wavelength by the diffraction grating onto the light-receiving surface of the optical sensor 28.

[0026] Furthermore, as shown in Figure 13, a pupil mirror PU and a slit mirror SLM may be placed between the slice mirror 1 and the light sensor 28. The pupil mirror PU is a mirror for rearranging the image divided by the slice mirror 1. The slit mirror SLM is a mirror for projecting the light image rearranged by the pupil mirror PU in a slit shape towards the light sensor 28.

[0027] Figure 2(a) is a schematic cross-sectional view of the surface spectroscopy unit 21 according to the embodiment, cut along the YZ plane. Figure 2(b) is an enlarged view of the portion enclosed by the dotted line A1 in Figure 2(a), i.e., a partially enlarged cross-sectional view of the slice mirror 1 (optical component). Figure 3 is an exploded perspective view illustrating the structure of the surface spectroscopy unit.

[0028] As shown in Figure 3, the surface spectroscopy unit 21 consists of an incident member 2, an intermediate member 3, an exit member 4, and bolts 5 for fastening and integrating them. Note that the incident member 2 and the intermediate member 3, and the intermediate member 3 and the exit member 4, may be connected to each other by means of fastening other than bolts 5, such as adhesive.

[0029] The incident-side member 2 has an incident slit 24 as an incident section and a second light-receiving section including a second group of reflective surfaces 26, and supports the second group of reflective surfaces 26. The intermediate member 3 is positioned between the incident-side member 2 and the exit-side member 4 and supports the incident-side member 2 and the exit-side member 4 so that they are fixed in a predetermined positional relationship. The exit-side member 4 has a slice mirror 1 (optical component) and an exit slit array 27, and supports the first group of reflective surfaces of the slice mirror 1. Therefore, the incident-side member 2, the intermediate member 3, and the exit-side member 4 can function as a support SP (supporter) that supports the first and second light-receiving sections. The first virtual plane IP1 intersects the incident-side member 2, the second virtual plane IP2 intersects the exit-side member 4, and the third virtual plane IP3 intersects the intermediate member 3.

[0030] The optical elements and components included in the surface spectroscopy unit 21 are concentrated in the incident member 2 and the exit member 4, and are integrated via the intermediate member 3 which acts as a support SP, so that the relative positions of the optical elements and components are positioned with high precision. The incident member 2, the intermediate member 3, and the exit member 4 constitute the support SP that supports the slice mirror 1 and the second reflective surface group 26. Furthermore, the outer casings of the incident member 2 to the exit member 4 can also function as light-shielding members (covers) that block external light attempting to enter the optical path space within the surface spectroscopy unit 21.

[0031] Figure 4 is a plan view of the incident member 2 as seen from the exit member 4 side (i.e., the slice mirror 1 side) along the Z-plus direction. The incident member 2 is provided with the incident slit 24 shown in Figure 1 and the second reflective surface group 26. In Figure 4, the second reflective surface group 26 is schematically illustrated as a mirror array consisting of 10 individual mirrors. Individual mirrors 26(1) to 26(10) are positioned where reflected light from the individual segmented mirrors constituting the slice mirror 1 reaches. The number and position of the individual mirrors can be set according to the number of individual segmented mirrors constituting the slice mirror 1 and the orientation of the reflective surfaces.

[0032] Figure 5(a) is a plan view of the exit-side member 4 as seen from the inlet-side member 2 side (i.e., the inlet slit 24 side) along the Z-minus direction. The exit-side member 4 is provided with the slice mirror 1 and the exit slit array 27 shown in Figure 1.

[0033] The exit slit array 27 is illustrated in Figure 5(a) as a slit array consisting of 10 individual slits. Individual slits 27(1) to 27(10) are arranged to individually transmit the 10 light beams that have been reflected and collimated by the second reflective surface group 26. The number and position of the individual slits can be set according to the number of individual segmented mirrors constituting the slice mirror 1 and the orientation of the reflective surface, in other words, according to the number and position of the individual mirrors constituting the second reflective surface group 26.

[0034] Figure 5(b) is an enlarged plan view showing the slice mirror 1 described in Figure 5(a). The slice mirror 1 is equipped with 10 segmented mirrors 1(1) to 1(10) for reflecting the incident light 23 (observation light) that enters through the incident slit 24 as 10 divided light beams in different directions. The slice mirror 1 is configured such that the 10 light beams reflected by the segmented mirrors 1(1) to 1(10) illuminate the individual mirrors 26(1) to 26(10) of the second reflective surface group 26.

[0035] In surface spectroscopy, it is desirable that the observation light be evenly divided by the slice mirrors. Therefore, the reflective surfaces of the 1(1) to 1(10) reflective surfaces can be configured to have equal area and shape. Furthermore, it is desirable that even the outermost reflective surface of the slice mirrors be illuminated by the observation light without any gaps in its entirety. Theoretically, the outer edge of the outermost reflective surface and the outer edge of the illumination area of ​​the observation light should be precisely aligned. However, considering mechanical assembly precision and positional shifts over time, this is not practical. Therefore, in order to ensure that the outermost reflective surface of the slice mirrors is also illuminated by the observation light without any gaps, the illumination area of ​​the observation light can be set to be slightly wider than the reflective area of ​​the slice mirrors (the entire area where multiple reflective surfaces are provided). Furthermore, in order to ensure that the observation light can illuminate the entire surface of each of the segmented mirrors 1(1) to 1(10), the position and aperture shape of the incident slit 24 are set so that the incident light 23 can illuminate the first light-receiving section 23A (shown enclosed by a dotted line), which is slightly larger than the area in which the segmented mirrors are arranged.

[0036] For the sake of explanation, as shown in Figures 2(a) and 5(b), the region within the first light-receiving unit 23A where the segmented mirrors 1(1) to 1(10) are arranged is called the first reflective surface group RA. Furthermore, the peripheral region within the first light-receiving unit 23A that is outside the region where the segmented mirrors are arranged is called the peripheral part of the first reflective surface group RA, or the "specific incident surface." This specific incident surface is separate from the reflective surfaces of the first reflective surface group RA of the first light-receiving unit 23A. In order to spectrally analyze the incident light 23 with as little loss as possible and to ensure spectral accuracy, it is desirable that the incident light 23 is reliably irradiated onto the first reflective surface group RA, and that less incident light 23 is irradiated onto the specific incident surface in the peripheral part of the first reflective surface group RA. Therefore, when viewed along the Z direction, which is the optical axis direction of the incident light 23, it is preferable to set the position and aperture shape of the incident slit 24 such that, for example, the area of ​​the first light receiving section 23A is greater than 1.0 times and less than or equal to 1.3 times the area of ​​the first reflective surface group RA.

[0037] If the observed light extends beyond the reflection region of the slice mirror, it will be reflected by components outside the reflection region, resulting in stray light whose direction of propagation is not controlled, and it may reach the photosensor via an unintended optical path. Stray light incident on the photosensor becomes observation noise and reduces the spatial or frequency resolution in surface spectroscopy, which is undesirable. The incident light 23 that irradiates the peripheral part of the first reflection surface group RA is naturally not reflected by the segmented mirrors 1(1) to 1(10). If the incident light 23 that irradiates the peripheral part of the first reflection surface group RA becomes stray light and is incident on the individual mirrors of the second reflection surface group 26, it may be guided to the photosensor 28. Also, if stray light from the peripheral part of the first reflection surface group RA is incident on the exit slit array 27, it may be guided to the photosensor 28. If stray light and light reflected by the first reflective surface group RA superimpose on the light-receiving surface of the light sensor 28, noise due to the stray light component will be superimposed on the detection result of the light sensor 28, reducing the spatial or frequency spectral accuracy. Therefore, among the incident light 23 that is incident on a specific incident surface other than the first reflective surface group RA within the first light-receiving unit 23A, the light that passes through the second virtual plane IP2 and is emitted can be considered unwanted light. The presence of unwanted light degrades the optical characteristics. Therefore, the optical device of this embodiment has a structure in which at least a portion (preferably 50% or more, more preferably 75% or more, and even more preferably 90% or more) of the light incident on a specific incident surface other than the first reflective surface group RA does not pass through the second virtual plane IP2 and is emitted. This reduces unwanted light.

[0038] Therefore, in this embodiment, a stray light suppression means (stray light suppression unit) is provided to suppress stray light from occurring when light incident on the peripheral part of the first reflective surface group RA. In the example shown in Figure 5(b), optical control mirrors CM(1) ​​to CM(6) are arranged around the region where the segmented mirrors 1(1) to 1(10) are provided (i.e., the first reflective surface group RA). Optical control mirrors CM(1) ​​to CM(6) are mirrors that reflect light incident on the peripheral part of the first reflective surface group RA in a direction different from that of the individual mirrors of the second reflective surface group 26 (in a direction where no individual mirrors are arranged). The specific incident surfaces that can cause the unwanted light mentioned above may include these optical control mirrors CM(1) ​​to (6). The normal directions of each reflective surface of optical control mirror CM(1) ​​are different from each other, and may also be different from the direction of the optical axis OA (optical axis direction) and the normal direction of the reflective surfaces of the first reflective surface group RA. In the illustrated example, six light control mirrors are arranged, but the number of light control mirrors is not limited to six, as long as the incident light 23 irradiated onto the periphery of the first reflective surface group RA can be reflected in a different direction from the individual mirrors of the second reflective surface group 26. Also, the shape of each light control mirror is not limited to a rectangle. Light control mirrors can also be called stray light suppression mirrors.

[0039] As shown in Figures 2(a) and 2(b), most of the light incident on the first light receiving unit 23A through the incident slit 24, i.e., the light incident on the first reflective surface group RA, is reflected by the segmented mirrors 1(1) to 1(10) toward the individual mirrors 26(1) to 26(10) of the second reflective surface group 26. On the other hand, the light incident on the peripheral part (specific incident surface) of the first reflective surface group RA is reflected as peripheral reflected light 41 by the optical control mirrors CM(1) ​​and CM(2) in the example of Figure 2(b) showing the YZ cross section, in a predetermined direction different from the individual mirrors of the second reflective surface group 26. Although the XZ cross section is not shown, the light incident on the peripheral part of the first reflective surface group RA is reflected by one of the optical control mirrors CM(3) to CM(6) toward the individual mirrors of the second reflective surface group 26 in a predetermined direction different from the individual mirrors of the second reflective surface group 26.

[0040] Figure 6 is a perspective view showing the inner surface of the intermediate member 3 more clearly, with the incident side member 2 removed from the surface spectroscopy unit 21 to illustrate the optical path of peripheral reflected light reflected in a predetermined direction different from the second reflection surface group 26 by the light control mirror. The peripheral reflected light reflected in a predetermined direction by the light control mirror is incident on specific regions 31 to 36 on the inner surface of the intermediate member 3. Specific regions 34 to 36 are schematically shown with dotted lines to indicate that they are regions on the inner surface side of the intermediate member 3. It is preferable that specific regions 31 to 36 are also provided in the portion of the support SP located between the second virtual plane IP2 and the third virtual plane IP3. That is, the optical device has a structure in which at least a portion of the light incident on the specific incident surface (light control mirror CM) is reflected by the specific incident surface (light control mirror CM) and incident on the portion of the support SP located between the second virtual plane IP2 and the third virtual plane IP3. To achieve this, it is also preferable to adopt a structure in which the normal to the specific incident surface (light control mirror) intersects with a portion of the support SP located between the second virtual plane IP2 and the third virtual plane IP3 (part of the intermediate member 3 in this example). The direction of the normal to the specific incident surface (light control mirror) is a direction that represents the orientation of the specific incident surface and is a direction that characterizes the direction of incidence to the specific incident surface and the direction of reflection at the specific incident surface. By guiding the reflected light from the specific incident surface to a portion of the support SP located between the second virtual plane IP2 and the third virtual plane IP3 (specific regions 31 to 36), it is possible to suppress the direct incidence of reflected light from the specific incident surface to the second reflection surface group 26, thereby reducing unwanted light emitted from the second virtual plane IP2 among the light incident on the specific incident surface.

[0041] As a first method to further suppress the stray light of peripherally reflected light incident on specific regions 31 to 36, which is reflected in the direction of the second reflective surface group 26 or the output slit array 27, one can apply an anti-reflective treatment (provide an anti-reflective structure) to these regions 31 to 36. The treatment method is not particularly limited as long as it can suppress the reflection of light in the wavelength range included in the peripherally reflected light in the direction of the second reflective surface group 26 or the output slit array 27. For example, on the inner surface of specific regions 31 to 36 of the incident side member 2, one can perform a rough surface treatment to form a light scattering surface or a diffuse reflection surface, apply an anti-reflective film, or attach an anti-reflective member. In addition to rough surfaces where geometric optics such as diffuse reflection is dominant, it is also possible to adopt a wave optics-dominant structure that cancels out light (absorbs light) by utilizing light interference by providing an uneven structure with height differences or pitches smaller than the wavelength of the incident light in specific regions 31 to 36. Such fine uneven structures can be realized by laser surface treatment. By providing a light-absorbing structure in specific regions 31-36, the generation of unwanted light can be reduced as much as possible.

[0042] Methods for roughening the inner surface of the intermediate member 3 include, for example, blasting, etching, and laser surface treatment. By forming a diffuse reflection surface or a light scattering surface using these methods, the intensity of light reflected in the direction of the second reflection surface group 26 or the exit slit array 27 can be significantly reduced. Methods for forming an anti-reflective film on the inner surface of the intermediate member 3 include forming a film of a low-reflection material by methods such as painting, vapor deposition, or printing. By forming an anti-reflective film, the intensity of light reflected in the direction of the second reflection surface group 26 or the exit slit array 27 can be significantly reduced. Methods for attaching an anti-reflective member include, for example, bonding an optical mask or filter. By attaching an anti-reflective member, the intensity of light reflected in the direction of the second reflection surface group 26 or the exit slit array 27 can be significantly reduced.

[0043] As a second method to further suppress the stray light that incident on specific regions 31 to 36 and is reflected in the direction of the second reflection surface group 26 or the exit slit array 27, light-transmitting windows (apers or windows made of light-transmitting material) may be placed in these regions. That is, the stray light that incident on specific regions 31 to 36 may be guided outside the surface spectroscopy unit 21.

[0044] As a third method to further suppress stray light from peripherally reflected light incident on specific regions 31 to 36, mirrors may be provided in these regions to specularly reflect the peripherally reflected light in a direction where the second reflective surface group 26 and the output slit array 27 are not located. The anti-reflection treatment of the first method described above may be applied to the destination of the specularly reflected peripherally reflected light, or an aperture or window made of a light-transmitting material of the second method may be provided to guide the peripherally reflected light outside the surface spectroscopy unit 21. Alternatively, another mirror may be provided at the destination of the specularly reflected peripherally reflected light to cause multiple reflections and guide the peripherally reflected light in a direction where the second reflective surface group 26 and the output slit array 27 are not located.

[0045] As described above, according to this embodiment, it is possible to utilize most of the light incident on an image slicer type optical device by reflecting it with a split mirror, and moreover, it is possible to provide a technology that is advantageous in suppressing the generation of stray light. In other words, it is possible to provide optical components, optical systems, and optical devices that can achieve high spectral accuracy.

[0046] [Embodiment 2] The optical components, optical system, optical device, etc., according to Embodiment 2 will be described below. Matters similar to those in Embodiment 1 will be simplified or omitted from the explanation. In the optical device according to Embodiment 1, a light control mirror was arranged around the first reflective surface group RA of the slice mirror 1. Light incident on the peripheral part of the first reflective surface group RA was specularly reflected by the light control mirror and guided in a predetermined direction different from the direction of the individual mirrors of the second reflective surface group 26 or the exit slit array 27.

[0047] In contrast, in Embodiment 2, an anti-reflective treatment is applied to the area where the optical control mirror was located in Embodiment 1, that is, the peripheral area of ​​the first reflective surface group RA of the slice mirror 1. In Embodiment 2 as well, the position and aperture shape of the incident slit 24 are preferably set such that, when viewed along the Z direction, which is the optical axis direction of the incident light 23, the area of ​​the first light receiving section 23A is greater than 1.0 times and less than or equal to 1.3 times the area of ​​the first reflective surface group RA.

[0048] In this embodiment, by applying a reflection-suppressing treatment to the peripheral portion of the first reflective surface group RA, the light incident on this portion is prevented from becoming stray light and being reflected in the direction of the second reflective surface group 26 or the exit slit array 27. The treatment method is not particularly limited as long as it can suppress the reflection of light in the wavelength range included in the light incident on the peripheral portion of the first reflective surface group RA in the direction of the second reflective surface group 26 or the exit slit array 27. For example, the peripheral portion of the first reflective surface group RA of the slice mirror 1 can be roughened, an anti-reflective coating can be formed, or an anti-reflective member can be attached.

[0049] Figure 7 is a schematic cross-sectional view showing a surface spectroscopy unit 21 in which the peripheral portion of the first reflective surface group RA of the slice mirror 1 has been roughened, as an example of Embodiment 2. Figure 7, which explains Embodiment 2, corresponds to Figure 2(a) in the explanation of Embodiment 1.

[0050] The peripheral portion of the first reflective surface group RA of the slice mirror 1 has a roughened surface to form a diffusely reflecting surface. As a result, incident light 23 incident on this portion is dispersed and reflected in multiple directions as diffusely reflected light 42. Therefore, the intensity of light reflected in the direction of the second reflective surface group 26 or the output slit array 27 can be significantly reduced. Examples of methods for roughening the peripheral portion of the first reflective surface group RA of the slice mirror 1 include blasting, etching, and laser surface treatment.

[0051] Furthermore, when the base surface of the reflective material is roughened, the direction of diffusely reflected light reflected from the roughened surface spreads out around the specular reflection direction relative to the base surface. For this reason, for the peripheral portion of the first reflective surface group RA that is roughened, it is preferable to set the specular reflection direction of the base surface before roughening to a direction in which the second reflective surface group 26 and the output slit array 27 are not located.

[0052] One method for forming an anti-reflective coating on the peripheral portion of the first reflective surface group RA of the slice mirror 1 is to form a film of a low-reflection material by methods such as painting, vapor deposition, or printing. By forming an anti-reflective coating, the intensity of light reflected in the direction of the second reflective surface group 26 or the exit slit array 27 can be significantly reduced. It is preferable to set the specular reflection direction of the base surface before the anti-reflective coating is formed on the peripheral portion of the first reflective surface group RA where the anti-reflective coating is formed, in a direction in which the second reflective surface group 26 and the exit slit array 27 are not located.

[0053] One method for attaching an anti-reflective member to the periphery of the first reflective surface group RA of the slice mirror 1 is to adhere an optical mask, filter, anti-reflective film, or light-absorbing film to it. By attaching the anti-reflective member, the intensity of light reflected in the direction of the second reflective surface group 26 or the output slit array 27 can be reduced. It is preferable to set the specular reflection direction of the base surface before the anti-reflective member is attached to a direction in which the second reflective surface group 26 and the output slit array 27 are not located. In addition to rough surfaces where geometric optics such as diffuse reflection are dominant, it is also possible to employ a wave-distributing optics-dominant structure that cancels out light (absorbs light) by utilizing light interference by providing an uneven structure with height differences and / or pitches less than or equal to the wavelength of the incident light on a specific incident surface. Such fine uneven structures can be realized by laser surface treatment. By providing a light-absorbing structure on a specific incident surface, the generation of stray light can be reduced as much as possible.

[0054] According to this embodiment, it is possible to utilize most of the light incident on an image slicer-type optical device by reflecting it with a split mirror, and moreover, to provide a technology that is advantageous in suppressing the generation of stray light. In other words, it is possible to provide optical components, optical systems, and optical devices that can achieve high spectral accuracy.

[0055] [Embodiment 3] The optical components, optical systems, optical devices, etc., according to Embodiment 3 will be described below. Matters similar to those in Embodiment 1 or Embodiment 2 will be simplified or omitted from the explanation. In Embodiments 1 and 2, the peripheral portion of the first reflective surface group RA of the slice mirror 1 provided on the exit side member 4 was processed to suppress the stray light reflected from this portion from becoming incident on the individual mirrors of the second reflective surface group 26 or the exit slit array 27.

[0056] In contrast, the output-side member 4A according to Embodiment 3 is provided with a mask member 6 that masks the peripheral portion of the first reflective surface group RA of the slice mirror 1, on the side of the incident slit 24 than the slice mirror 1 in the optical axis direction (Z direction) of the incident light 23. In Embodiment 3 as well, when viewed along the Z direction, which is the optical axis direction of the incident light 23, it is preferable that the position and aperture shape of the incident slit 24 be set such that, for example, the area of ​​the first light-receiving section 23A is greater than 1.0 times and less than or equal to 1.3 times the area of ​​the first reflective surface group RA.

[0057] Figure 8(a) is a perspective view showing the external appearance of the ejection-side member 4A according to Embodiment 3, and Figure 8(b) is an exploded perspective view of the ejection-side member 4A according to Embodiment 3. As shown in Figure 8(b), the mask member 6 is fastened to the ejection-side member 4A by bolts 5. However, the mask member 6 may also be fixed to the ejection-side member 4A by other means such as adhesive. The mask member 6 is provided with an opening to expose the first reflective surface group RA of the slice mirror 1 to the incident slit 24 side.

[0058] As shown in Figure 8(a), in the assembled state, the first reflective surface group RA of the slice mirror 1 protrudes from the opening of the mask member 6 toward the incident slit 24 side (Z-positive direction), and the peripheral portion of the first reflective surface group RA of the slice mirror 1 is masked by the mask member 6.

[0059] In this embodiment as well, the first light-receiving section 23A is set to be larger than the first reflective surface group RA. However, incident light 23 incident on the peripheral portion of the first reflective surface group RA is irradiated onto the mask member 6, and the mask member 6 suppresses reflection in the direction of the second reflective surface group 26 or the output slit array 27. The mask member 6 is a member that has the function of suppressing reflection of incident light 23 in the direction of the second reflective surface group 26, and can be, for example, an optical filter or a light-shielding plate. In Embodiment 1 or Embodiment 2, there was a possibility of damaging the mirror surface of the segmented mirror when processing the peripheral portion of the first reflective surface group RA of the slice mirror 1, but in this embodiment, the mask member 6 is manufactured separately from the slice mirror 1. Therefore, the output-side member 4 including the slice mirror 1 can be manufactured with a high manufacturing yield.

[0060] According to this embodiment, it is possible to utilize most of the light incident on an image slicer-type optical device by reflecting it with a split mirror, and moreover, to provide a technology that is advantageous in suppressing the generation of stray light. In other words, it is possible to provide optical components, optical systems, and optical devices that can achieve high spectral accuracy.

[0061] [Embodiment 4] Figure 9 shows a perspective view of the output-side member 4C according to Embodiment 4, and Figure 10(a) shows a front view of the output-side member 4C according to Embodiment 4. Figure 10(b) shows an enlarged view of the region A2 enclosed by the dotted line in Figure 10(a). Figure 10(b) can also be said to show an enlarged view of the irradiation region where incident light is irradiated through the incident slit 24.

[0062] Figure 11(a) is a schematic cross-sectional view of the surface spectroscopy unit 21C according to Embodiment 4, cut along the YZ plane. Figure 11(b) is an enlarged view of portion A3 enclosed by the dotted line in Figure 11(a). That is, Figure 11(b) is a partially enlarged cross-sectional view of the slice mirror 1C according to Embodiment 4. In Embodiment 4 as well, incident light is irradiated to an irradiation area wider than the divided reflection area. This makes it possible to effectively utilize the divided reflection area.

[0063] In Embodiment 4, the peripheral portion of the segmented reflection region of the slice mirror 1C is configured as a structural portion 43 for mechanically supporting the segmented reflection region in which the segmented mirrors are arranged. Furthermore, the orientation and shape of the surface of the structural portion 43 are composed of a plane perpendicular to the optical axis and a plane parallel to the optical axis. Therefore, incident light incident on the peripheral portion of the segmented reflection region is reflected by the plane of the structural portion 43, which is made of reflective material, that is perpendicular to the optical axis. The plane perpendicular to the optical axis in the structural portion 43 becomes the specific incident plane. A small portion of the reflected light 44 that is incident on the specific incident plane parallel to the optical axis and reflected by the structural portion 43 can exit from the incident slit 24. However, the majority of the reflected light 44 reflected by the structural portion 43 can become stray light that reaches the position where the second reflective surface group 26 is located with relatively strong intensity. Alternatively, the reflected light 44 can become stray light and reach the exit slit array 27. Note that the surface of the structural portion for mechanically supporting the slice mirror 1C is not necessarily a plane parallel to the XY plane. For example, the base side surfaces of the slice mirror 1C (surfaces parallel to the XZ and YZ planes) are also included, and light diffusely reflected multiple times through these surfaces can also become stray light reaching the second reflection surface group 26 or the output slit array 27.

[0064] Thus, in the surface spectroscopy unit 21C according to Embodiment 4, the configuration of the peripheral part of the first reflective surface group RA differs from that of Embodiments 1 to 3. For this reason, when the slice mirror 1C of Embodiment 4 is equipped with segmented mirrors 1(1) to 1(10) of the same shape as those in the above-described embodiments, the intensity of stray light reaching the optical sensor via the second reflective surface group 26 was much greater than that of Embodiments 1 to 3. Therefore, the optical device using the output-side member 4C according to Embodiment 4 could not achieve the same high spectral accuracy as Embodiments 1 to 3.

[0065] [Other embodiments] It should be noted that the present invention is not limited to the embodiments described above, and many modifications are possible within the technical concept of the present invention. For example, all or part of the different embodiments described above may be combined and implemented.

[0066] For example, the light-controlled mirrors CM(1) ​​to CM(6) shown in Embodiment 1 may be configured as a mask member 6 as in Embodiment 3. Alternatively, the processing performed on the peripheral portion of the first reflective surface group RA of the slice mirror 1 in Embodiment 2 may be performed on the mask member 6 shown in Embodiment 3.

[0067] This specification discloses at least the following: [Item 1] A first light-receiving unit having a first group of reflective surfaces, A second light-receiving unit having a second group of reflective surfaces, An optical device comprising a support for the first light-receiving unit and the second light-receiving unit, With respect to a first virtual plane perpendicular to the optical axis of the optical device and intersecting the support, a second virtual plane perpendicular to the optical axis and intersecting the support, and a third virtual plane perpendicular to the optical axis and between the first and second virtual planes, the first light-receiving unit is located between the third and second virtual planes, and the second light-receiving unit is located between the first and third virtual planes. The first group of reflective surfaces reflects light incident through the first virtual plane in multiple different directions nonparallel to the optical axis, the second group of reflective surfaces reflects the light reflected by the first group of reflective surfaces, and the light reflected by the second group of reflective surfaces exits through the second virtual plane. The optical device has a structure in which the first light-receiving unit has an incident surface to which the light incident through the first virtual plane is incident, separate from the first group of reflective surfaces, and at least a portion of the light incident on the incident surface does not exit through the second virtual plane. [Matter 2] A first light-receiving unit having a first group of reflective surfaces, A second light-receiving unit having a second group of reflective surfaces, An optical device comprising a support for the first light-receiving unit and the second light-receiving unit, With respect to a first virtual plane perpendicular to the optical axis of the optical device and intersecting the support, a second virtual plane perpendicular to the optical axis and intersecting the support, and a third virtual plane perpendicular to the optical axis and between the first and second virtual planes, the first light-receiving unit is located between the third and second virtual planes, and the second light-receiving unit is located between the first and third virtual planes. The first group of reflective surfaces reflects light incident through the first virtual plane in multiple different directions nonparallel to the optical axis, the second group of reflective surfaces reflects the light reflected by the first group of reflective surfaces, and the light reflected by the second group of reflective surfaces exits through the second virtual plane. The optical device has a structure in which the first light-receiving unit has an incident surface to which the light incident through the first virtual plane is incident, separate from the first group of reflective surfaces, and at least a portion of the light incident on the incident surface is reflected by the incident surface and incident on the portion of the support located between the second virtual plane and the third virtual plane. [Matter 3] The second virtual plane is located between the fourth virtual plane perpendicular to the optical axis and the third virtual plane, and light passing through the second virtual plane passes through the fourth virtual plane. The optical device described in item 1 or 2. [Matter 4] Between the fourth virtual plane and the second virtual plane, there is a spectral unit that spectrally separates the light that has passed through the third virtual plane. Optical device as described in item 3. [Matter 5] The aforementioned spectroscopic section is a diffraction grating. Optical device as described in item 4. [Matter 6] The incident surface includes a first mirror that reflects the light irradiated onto the incident surface in a direction different from the second group of reflective surfaces provided by the second light receiving unit. An optical device as described in any one of items 1 to 5. [Matter 7] The structure comprises, at a position where light irradiated onto the incident surface and reflected by the first mirror is irradiated, any of the following: a light scattering surface, an anti-reflective coating, a light transmission window, or a second mirror that reflects the light reflected by the first mirror in a direction different from that of the second light receiving section. The optical device described in item 6. [Matter 8] The aforementioned light-transmitting window is an opening provided in a support, or a window made of a light-transmitting material. Optical apparatus as described in item 7. [Matter 9] The first light-receiving unit comprises one of the following: a diffuse reflection surface, an anti-reflective coating, an anti-reflective member, or a mask member, which are arranged outside the first group of reflective surfaces. An optical apparatus as described in any one of items 1 through 8. [Matter 10] The diffuse reflection surface, the anti-reflective coating, or the anti-reflective member is provided on a structural part located outside the first group of reflective surfaces. Optical device as described in item 9. [Matter 11] The mask member covers the structural part located outside the first group of reflective surfaces. The optical device described in item 10. [Matter 12] The area of ​​the first light-receiving section is greater than 1.0 times and less than or equal to 1.3 times the area of ​​the first reflective surface group. An optical device as described in any one of items 1 through 11. [Matter 13] The normal to the incident plane intersects the portion of the support located between the second virtual plane and the third virtual plane. An optical apparatus as described in any one of items 1 through 12. [Matter 14] The structure has such that 50% or more of the light incident on the first group of reflective surfaces exits through the second virtual plane, and 50% or more of the light incident on the incident surface does not exit through the second virtual plane. An optical apparatus as described in any one of items 1 through 13. [Matter 15] The support includes a first member that supports the first light-receiving portion, a second member that supports the second light-receiving portion, and a third member that fixes the first member and the second member. An optical device as described in any one of items 1 through 14. [Matter 16] The first virtual plane intersects the second member, the second virtual plane intersects the first member, and the third virtual plane intersects the third member. Optical device as described in item 15. [Matter 17] Between the fourth virtual plane and the second virtual plane, there is a slit array that transmits each of the multiple light beams reflected by the second light receiving unit. Optical device as described in item 3. [Matter 18] Between the fourth virtual plane perpendicular to the optical axis and the third virtual plane, there is a pupil mirror that arranges a plurality of light beams reflected by the second light receiving unit. Optical device as described in item 3. [Matter 19] The optical device described in item 3, A sensor that detects light emitted through the fourth virtual plane, Optical system. [Matter 20] The system includes a computer that performs information processing related to surface spectroscopy based on the detection results of the aforementioned sensor. The optical system described in item 19.

[0068] Furthermore, if this specification contains a statement such as "A is B," even if it omits a statement such as "A is not B," it can be said that this specification discloses that "A is not B." This is because the statement "A is B" implies that the case where "A is not B" is being considered. [Explanation of Symbols]

[0069] 1...Slice mirror / 1(1)~1(10)...Segmented mirror / 2...Incident side member / 2a...Reflective surface / 3...Intermediate member / 4, 4A...Output side member / 5...Bolt / 21...Surface spectral unit / 23...Incident light / 23A...First light receiving section / 24...Incident slit / 25-1~25-4...Reflected light / 26...Second reflective surface group / 26(1)~26(10)...Individual mirrors / 27...Output slit array / 27(1)~27(10)···Individual slits / 28···Optical sensor / 31~36···Specific area / 41···Peripheral reflected light / 42···Diffuse reflected light / 43···Structural part / 100···Information processing device / CM(1)~CM(6)···Optical control mirror / IP1···First virtual plane / IP2···Second virtual plane / IP3···Third virtual plane / IP4···Fourth virtual plane / OA···Optical axis / RA···First reflective surface group / SP···Support

Claims

1. A first light-receiving unit having a first group of reflective surfaces, A second light-receiving unit having a second group of reflective surfaces, An optical device comprising a support for the first light-receiving unit and the second light-receiving unit, With respect to a first virtual plane perpendicular to the optical axis of the optical device and intersecting the support, a second virtual plane perpendicular to the optical axis and intersecting the support, and a third virtual plane perpendicular to the optical axis and between the first and second virtual planes, the first light-receiving unit is located between the third and second virtual planes, and the second light-receiving unit is located between the first and third virtual planes. The first group of reflective surfaces reflects light incident through the first virtual plane in multiple different directions nonparallel to the optical axis, the second group of reflective surfaces reflects the light reflected by the first group of reflective surfaces, and the light reflected by the second group of reflective surfaces exits through the second virtual plane. The optical device has a structure in which the first light-receiving unit has an incident surface to which the light incident through the first virtual plane is incident, separate from the first group of reflective surfaces, and at least a portion of the light incident on the incident surface does not exit through the second virtual plane.

2. A first light-receiving unit having a first group of reflective surfaces, A second light-receiving unit having a second group of reflective surfaces, An optical device comprising a support for the first light-receiving unit and the second light-receiving unit, With respect to a first virtual plane perpendicular to the optical axis of the optical device and intersecting the support, a second virtual plane perpendicular to the optical axis and intersecting the support, and a third virtual plane perpendicular to the optical axis and between the first and second virtual planes, the first light-receiving unit is located between the third and second virtual planes, and the second light-receiving unit is located between the first and third virtual planes. The first group of reflective surfaces reflects light incident through the first virtual plane in multiple different directions nonparallel to the optical axis, the second group of reflective surfaces reflects the light reflected by the first group of reflective surfaces, and the light reflected by the second group of reflective surfaces exits through the second virtual plane. The optical device has a structure in which the first light-receiving unit has an incident surface to which the light incident through the first virtual plane is incident, separate from the first group of reflective surfaces, and at least a portion of the light incident on the incident surface is reflected by the incident surface and incident on the portion of the support located between the second virtual plane and the third virtual plane.

3. The second virtual plane is located between the fourth virtual plane perpendicular to the optical axis and the third virtual plane, and light passing through the second virtual plane passes through the fourth virtual plane. The optical apparatus according to claim 1 or 2.

4. Between the fourth virtual plane and the second virtual plane, there is a spectral unit that spectrally separates the light that has passed through the third virtual plane. The optical apparatus according to claim 3.

5. The aforementioned spectroscopic section is a diffraction grating. The optical apparatus according to claim 4.

6. The incident surface includes a first mirror that reflects the light irradiated onto the incident surface in a direction different from the second group of reflective surfaces provided by the second light receiving unit. The optical apparatus according to claim 1 or 2.

7. The structure includes, at a position where the light irradiated onto the incident surface and reflected by the first mirror is irradiated, any of the following: a light scattering surface, an anti-reflective coating, a light transmission window, or a second mirror that reflects the light reflected by the first mirror in a direction different from that of the second light receiving section. The optical apparatus according to claim 6.

8. The aforementioned light-transmitting window is an opening provided in a support, or a window made of a light-transmitting material. The optical apparatus according to claim 7.

9. The first light-receiving unit comprises one of the following: a diffuse reflection surface, an anti-reflective coating, an anti-reflective member, or a mask member, which are arranged outside the first group of reflective surfaces. The optical apparatus according to claim 1 or 2.

10. The diffuse reflection surface, the anti-reflective coating, or the anti-reflective member is provided on a structural part located outside the first group of reflective surfaces. The optical apparatus according to claim 9.

11. The mask member covers the structural part that is located outside the first group of reflective surfaces. The optical apparatus according to claim 10.

12. The area of ​​the first light-receiving section is greater than 1.0 times and less than or equal to 1.3 times the area of ​​the first reflective surface group. The optical apparatus according to claim 1 or 2.

13. The normal to the incident plane intersects the portion of the support located between the second virtual plane and the third virtual plane. The optical apparatus according to claim 1 or 2.

14. The structure has such that 50% or more of the light incident on the first group of reflective surfaces exits through the second virtual plane, and 50% or more of the light incident on the incident surface does not exit through the second virtual plane. The optical apparatus according to claim 1 or 2.

15. The support includes a first member that supports the first light-receiving portion, a second member that supports the second light-receiving portion, and a third member that fixes the first member and the second member. The optical apparatus according to claim 1 or 2.

16. The first virtual plane intersects the second member, the second virtual plane intersects the first member, and the third virtual plane intersects the third member. The optical apparatus according to claim 15.

17. Between the fourth virtual plane and the second virtual plane, there is a slit array that transmits each of the multiple light beams reflected by the second light receiving unit. The optical apparatus according to claim 3.

18. A pupil mirror is provided between a fourth virtual plane perpendicular to the optical axis and the third virtual plane, which arranges a plurality of light beams reflected by the second light receiving unit. The optical apparatus according to claim 3.

19. The optical apparatus according to claim 3, A sensor that detects light emitted through the fourth virtual plane, Optical system.

20. The system includes a computer that performs information processing related to surface spectroscopy based on the detection results of the aforementioned sensor. The optical system according to claim 19.

Images