Optical system and electromagnetic wave detection device

Abstract

This optical system has a first optical member and a focusing optical system. The first optical member advances a first electromagnetic wave radiated from a first radiation unit in a first direction. The focusing optical system at least includes an optical element. The focusing optical system focuses the first electromagnetic wave incident on the optical element. A reflected wave is incident on the optical element. The reflected wave passes through a predetermined region in which the first electromagnetic wave is reflected by an object and which includes the first optical member.

Description

Optical system and electromagnetic wave detection device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from Japanese Patent Application No. 2024-013587, filed on January 31, 2024, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to an optical system and an electromagnetic wave detection device.

[0003] In distance measuring devices such as Lidar, a half mirror is used to align the propagation axes of the radiation wave emitted from the radiation source and the reflected wave from the irradiated wave, and the reflected wave that passes through the half mirror is detected by a detector (see Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2003-172612

[0005] An optical system according to a first aspect includes: a first optical member that causes a first electromagnetic wave radiated from a first radiating portion to travel in a first direction; and a focusing optical system that includes an optical element onto which a reflected wave that is formed by the first electromagnetic wave reflected by an object and that has passed through a predetermined region including the first optical member is incident, and that focuses the first electromagnetic wave that has incident on the optical element.

[0006] An electromagnetic wave detection device according to a second aspect further comprises: a first optical member that causes a first electromagnetic wave radiated from a first radiation unit to travel in a first direction; a focusing optical system that includes an optical element onto which a reflected wave of the first electromagnetic wave that has been reflected by an object and passed through a predetermined area including the first optical member is incident, and that focuses the first electromagnetic wave that has been incident on the optical element; and a scanning unit that changes the radiation direction of the first electromagnetic wave traveling in the first direction and causes a reflected wave of the radiated first electromagnetic wave that has been reflected by the object to travel to the optical element, wherein the optical element is a concave mirror, and the focusing optical system and a light-guiding optical system that guides the reflected wave emitted from the concave mirror in a third direction, the concave mirror further comprising: a second optical element that at least partially overlaps with the light-guiding optical system when viewed from the first direction and has a hole that passes the first electromagnetic wave guided by the light-guiding optical system, and causes a second electromagnetic wave in a band different from the first electromagnetic wave radiated from the second radiation unit to travel in the first direction and transmits the first electromagnetic wave; and a third optical element that is provided on the object side of the scanning unit and transmits the first electromagnetic wave and changes the traveling direction of the second electromagnetic wave, the second optical element comprising: an optical system located between the first optical element and the scanning unit; a first detection unit that detects the first electromagnetic wave traveling in the third direction; a second detection unit that detects the second electromagnetic wave traveling from the third optical element; and a control unit that detects, based on the detection result of the second detection unit, an orientation of a reflective surface at which the scanning unit changes the radiation direction of the first electromagnetic wave and the second electromagnetic wave.

[0007] 1. A functional block diagram showing a schematic configuration of an electromagnetic wave detection device including an optical system according to a first embodiment. It is a configuration diagram of the optical system of FIG. 1. It is a diagram showing a traveling path of a first electromagnetic wave reflected at an object in the optical system of FIG. 2. It is a configuration diagram of a modified example of the optical system of FIG. 2. It is a configuration diagram showing another modified example of the optical system of FIG. 2. It is a diagram showing a traveling path of a first electromagnetic wave reflected at an object in the optical system of FIG. 5. It is a perspective view for explaining the arrangement of a third mirror, an extraction mirror, and a second detection device. It is a diagram seen from a direction perpendicular to both the first secondary corresponding direction and the second secondary corresponding direction for explaining the arrangement of a slit plate relative to the extraction mirror. It is a configuration diagram of an optical system according to a second embodiment. It is a diagram showing a traveling path of a first electromagnetic wave reflected at an object in the optical system of FIG. 9. It is a configuration diagram of an optical system according to a third embodiment. It is a diagram showing a traveling path of a first electromagnetic wave reflected at an object in the optical system of FIG. 11. It is a configuration diagram of an optical system according to a fourth embodiment.

[0008] Hereinafter, embodiments of an optical system to which the present disclosure is applied will be described with reference to the drawings.

[0009] 1 , an electromagnetic wave detection device 11 including an optical system 10 according to the first embodiment of the present disclosure is configured to include the optical system 10, a first emitter 12, a first detector 13, and a controller 14. The electromagnetic wave detection device 11 may further include a second emitter 15 and a second detector 16.

[0010] In the drawings of the present application, electromagnetic waves are depicted by dashed lines, and wireless or wired communication lines for communicating signals between functional blocks are depicted by solid lines.

[0011] An overview of the electromagnetic wave detection device 11 will be described. Electromagnetic waves emitted by a first emitter 12 are irradiated onto an object ob via an optical system 10. Reflected waves of the electromagnetic waves irradiated onto the object ob are incident on a first detector 13 via the optical system 10. A controller 14 generates information about the object ob based on the electromagnetic waves radiated by the first emitter 12 and the reflected waves detected by the first detector 13. The configuration of each part of the electromagnetic wave detection device 11 will be described in detail below.

[0012] In this specification, a mirror reflecting an electromagnetic wave may mean that the mirror reflects the electromagnetic wave with a reflectance of more than 50%. Furthermore, the reflectance of the mirror to the electromagnetic wave is preferably more than 70%, more preferably more than 80%, even more preferably more than 90%, and most preferably substantially 100%.

[0013] In the present specification, a mirror that transmits an electromagnetic wave may mean that the mirror transmits the electromagnetic wave at a transmittance of more than 50%. Furthermore, the transmittance of the mirror for the electromagnetic wave is preferably more than 70%, more preferably more than 80%, even more preferably more than 90%, and most preferably substantially 100%.

[0014] As shown in Fig. 2, the optical system 10 includes a first mirror 17 and a focusing optical system 18. The optical system 10 may further include a scanning unit 19, a second mirror 20, and a third mirror 21. In Fig. 2, the first electromagnetic wave and the second electromagnetic wave are indicated by dashed lines. The optical system 10 may be housed in a lens barrel.

[0015] The first mirror 17, which is a first optical member, is located on the radiation path of the first electromagnetic wave em1 emitted by the first radiator 12. The first mirror 17 may be located, for example, in the radiation direction of the first electromagnetic wave em1 emitted by the first radiator 12. Alternatively, the first mirror 17 may be located, for example, in a direction in which the first electromagnetic wave em1 emitted by the first radiator 12 is deflected using at least one mirror.

[0016] The first mirror 17 may have a size equal to or smaller than the cross-sectional area of ​​the bundle of the first electromagnetic wave em1 when viewed from the radiation path of the first electromagnetic wave em1.

[0017] The first mirror 17 reflects the first electromagnetic wave em1 in a first direction d1. The first mirror 17 may be reflective or transmissive to a second electromagnetic wave em2, which will be described later, depending on the arrangement of the second mirror 20, which is a second optical member.

[0018] The first mirror 17 may be a plane mirror. As will be described later, in a configuration in which the first electromagnetic wave em1 emitted by the first radiator 12 is collimated, or in a configuration in which the first radiator 12 radiates the beam-shaped first electromagnetic wave em1, the first mirror 17 is a plane mirror, so that the first electromagnetic wave em1 can be irradiated to the object ob while remaining in a beam shape. Alternatively, the first mirror 17 may be a curved mirror. The curved first mirror 17 may collimate the first electromagnetic wave em1 emitted by the first radiator 12.

[0019] The focusing optical system 18 is positioned in a second direction d2 relative to the first mirror 17. The second direction d2 is the opposite direction to the first direction d1. The focusing optical system 18 focuses the first electromagnetic wave em1 traveling in the second direction d2. In this specification, traveling in the second direction d2 means a direction that includes the second direction d2 as a component.

[0020] The focusing optical system 18 includes at least a first optical element 22. A first electromagnetic wave em1 traveling in a second direction d2, which is a wave obtained when the first electromagnetic wave is reflected by an object, is incident on the first optical element 22. The first electromagnetic wave em1 traveling in the second direction d2 passes through a predetermined region including the first mirror 17. The focusing optical system 18 may further include a light-guiding optical system 23.

[0021] When viewed from the first direction d1, at least a portion of the first optical element 22 overlaps with the first mirror 17, and another portion is outside the first mirror 17. When viewed from the first direction d1, the first optical element 22 may have a larger area than the first mirror 17. When viewed from the first direction d1, the first optical element 22 may contain the first mirror 17. The first optical element 22 may be a concave mirror having a concave surface facing the first direction d1. The first optical element 22, which is a concave mirror, may have a hole hl formed therein, the hole hl having at least a portion overlapping with the light-guiding optical system 23 when viewed from the first direction d1. The first optical element 22 may be housed in a lens barrel that houses the optical system 10. The first optical element 22 may be configured as a bottom surface on the second direction d2 side of the lens barrel that houses the optical system 10.

[0022] The light-guiding optical system 23 may be configured with at least one second optical element 24. One second optical element 24 may be located between the first mirror 17 and the first optical element (concave mirror) 22. The second optical element 24 located between the first mirror 17 and the first optical element 22 may be located closer to the first optical element 22 than the focal point of the first optical element 22. In the first embodiment, the light-guiding optical system 23 may include a single second optical element 24. The second optical element 24 may be a convex mirror having a convex surface facing the second direction d2. The radius of curvature of the convex mirror of the second optical element 24 may be longer than the radius of curvature of the first optical element 22.

[0023] 3 , the light-guiding optical system 23 may guide the first electromagnetic wave em1 reflected from the first optical element (concave mirror) 22 in the third direction d3. In the first embodiment, the third direction d3 is the second direction d2. The light-guiding optical system 23 may focus a parallel light beam that is incident on the first optical element 22 and is parallel to the second direction d2, on the second direction d2 side of the first optical element (concave mirror) 22.

[0024] The scanning unit 19 may be located on the first direction d1 side of the first mirror 17. The scanning unit 19 may change the radiation direction of the first electromagnetic wave em1 reflected by the first mirror 17. The scanning unit 19 may further change the radiation direction of the second electromagnetic wave em2 reflected by the second mirror 20 described below. The scanning unit 19 may cause the reflected wave of the first electromagnetic wave em1 radiated toward the target ob to travel to the first optical element 22.

[0025] The scanning unit 19 may, for example, radiate the first electromagnetic wave em1 in a plurality of different directions in space by reflecting it while changing its direction. The scanning unit 19 may change the direction in which the first electromagnetic wave em1 is reflected based on the control of the control unit 14. The scanning unit 19 may change the direction in which the first electromagnetic wave em1 is reflected around two intersecting axes serving as rotation axes. The two axes may be orthogonal. The two directions in which the scanning unit 19 oscillates around the two axes are referred to as first oscillation directions sd1 and sd2, respectively. The scanning unit 19 may include, for example, a MEMS (Micro Electro Mechanical Systems) mirror, a polygon mirror, a galvanometer mirror, or the like.

[0026] The second mirror 20 may be located on a path of the second electromagnetic wave em2 emitted by the second emitting unit 15. The second mirror 20 may emit the second electromagnetic wave em2 to the scanning unit 19 from a second direction d2.

[0027] In a specific first arrangement example, the second mirror 20 may be located in the first direction d1 from the first mirror 17 between the first mirror 17 and the scanning unit 19. The second mirror 20 may reflect the second electromagnetic wave em2 in the first direction d1.

[0028] In the first exemplary arrangement, the second mirror 20 may transmit the first electromagnetic wave em1 and may reflect the second electromagnetic wave em2.

[0029] 4 , in a second specific example of the arrangement of the second mirror 20, the second mirror 20 may be located between the first radiating unit 12 and the first mirror 17 in the radiation direction of the first electromagnetic wave em1 by the first radiating unit 12. The second mirror 20 may reflect the second electromagnetic wave em2 in the same direction as the radiation path direction of the first electromagnetic wave em1.

[0030] In the second arrangement example, the second mirror 20 may transmit the first electromagnetic wave em1. The second mirror 20 may reflect the second electromagnetic wave em2. Also, in the second arrangement example, the first mirror 17 may reflect the second electromagnetic wave em2.

[0031] 5 , in a third specific example arrangement of the second mirror 20, the second mirror 20 may be located in the second direction d2 from the light-guiding optical system 23. The second mirror 20 may be located together with the first mirror 17, sandwiching the second optical element 24 therebetween. Alternatively, the second mirror 20 may be located between the first detection unit 13 and the first optical element 22. Alternatively, the second mirror 20 may be located between the first mirror 17 and the second optical element 24. The second mirror 20 may reflect the second electromagnetic wave em2 in the first direction d1.

[0032] 6 , in the third arrangement example, the second mirror 20 may transmit the first electromagnetic wave em1. The second mirror 20 may reflect the second electromagnetic wave em2. Also, in the third arrangement example, the first mirror 17 may transmit the second electromagnetic wave em2. Also, in the third arrangement example, the second optical element 24 may transmit the second electromagnetic wave em2.

[0033] The third mirror 21, which is the third optical member, may be located closer to the object side than the scanning unit 19. The third mirror 21 may further be located so as to overlap with the traveling path of at least a part or all of the electromagnetic waves deflected by the scanning unit 19.

[0034] The third mirror 21 may transmit the first electromagnetic wave em1. The third mirror 21 may reflect the second electromagnetic wave em2. The third mirror 21 may be tilted with respect to the first direction d1.

[0035] The first radiator 12 may emit a first electromagnetic wave em1. The first electromagnetic wave em1 may include, for example, at least one of infrared light, visible light, ultraviolet light, and radio waves. In the first embodiment, the first electromagnetic wave em1 may be invisible light such as infrared light. The first radiator 12 may emit the first electromagnetic wave em1 in a narrow beam shape, for example, 0.5°. Alternatively, the first radiator 12 may emit the first electromagnetic wave em1 in a pulsed manner. The first radiator 12 may switch between emitting and stopping the first electromagnetic wave em1 based on control by the control unit 14, which will be described later. The first radiator 12 includes a radiation source, for example, an LD (Laser Diode) or an LED (Light Emitting Diode). The first radiating section 12 may further include an optical element that collimates the first electromagnetic wave em1 radiated by the radiation source.

[0036] The first detector 13 may be provided near a position where the first electromagnetic wave em1 is focused by the focusing optical system 18. Specifically, the first detector 13 may be located in the third direction d3 from the light-guiding optical system 23. In the first embodiment, the first detector 13 may be located in the second direction d2 from the first optical element 22. Furthermore, the first detector 13 may overlap the hole hl when viewed in the second direction d2. The first detector 13 detects the first electromagnetic wave em1 traveling in the third direction d3 from the light-guiding optical system 23. The first detector 13 may transmit detection information indicating that a reflected wave from an object has been detected to the control unit 14 as a signal.

[0037] More specifically, the first detection unit 13 includes elements constituting a distance measurement sensor. For example, the first detection unit 13 includes a single element such as an APD (Avalanche Photodiode), a PD (Photodiode), or a distance measurement image sensor. Alternatively, the first detection unit 13 may include an element array such as an APD array, a PD array, a distance measurement imaging array, or a distance measurement image sensor.

[0038] The second radiator 15 may radiate a second electromagnetic wave em2. The second electromagnetic wave em2 may include, for example, at least one of infrared light, visible light, ultraviolet light, and radio waves. The band of the second electromagnetic wave em2 may be different from the band of the first electromagnetic wave em1.

[0039] The second radiating unit 15 may emit the second electromagnetic wave em2 in a narrow beam shape, for example, with a width of 0.5°. Alternatively, the second radiating unit 15 may emit a continuous wave of the second electromagnetic wave em2. The first radiating unit 12 includes a radiation source such as an LD (Laser Diode) or an LED (Light Emitting Diode). The first radiating unit 12 may further include an optical element that collimates the first electromagnetic wave em1 emitted by the radiation source.

[0040] The second detector 16 may generate a signal for estimating the deflection direction of the first electromagnetic wave em1 by the scanner 19. Specifically, the second detector 16 may include an extraction mirror 25, a first detector element 26, and a second detector element 27.

[0041] As shown in FIG. 2 , the extraction mirror 25 may be located within the reflection range rr of the second electromagnetic wave em2 by the third mirror 21. The extraction mirror 25 may overlap only a portion of the first primary corresponding direction pcd1 within the reflection range rr. In other words, the extraction mirror 25 does not need to cover the entire reflection range rr in the first primary corresponding direction pcd1. The first primary corresponding direction pcd1 is the direction corresponding to the first oscillation direction sd1 of the second electromagnetic wave em2 reflected by the third mirror 21. Therefore, a portion of the second electromagnetic wave em2 reflected by the third mirror 21 and oscillated in the first primary corresponding direction pcd1 may be reflected by the extraction mirror 25, while another portion may pass through without entering the extraction mirror 25. Alternatively, the extraction mirror 25 may overlap the entire second primary corresponding direction pcd2 within the reflection range rr. In other words, the extraction mirror 25 may cover the entire reflection range rr in the second primary corresponding direction pcd2.

[0042] The first detection element 26 may be provided in a region where the second electromagnetic wave em2 swung in the first primary corresponding direction pcd1 passes through without being incident on the extraction mirror 25. A plurality of first detection elements 26 may be positioned so as to be aligned along the first primary corresponding direction pcd1. Each first detection element 26 may detect the second electromagnetic wave em2 when the radiation direction of the second electromagnetic wave em2 is directed toward an arbitrary point in the first primary corresponding direction pcd1. The first detection element 26 may transmit a detection signal to the control unit 14 when detecting the second electromagnetic wave em2.

[0043] Note that a cylindrical lens may be provided farther from the third mirror 21 than the extraction mirror 25 and closer to the first detection element 26. The cylindrical lens may bend the second electromagnetic wave em2 in the second primary corresponding direction pcd2.

[0044] The second detection element 27 may be provided in a direction in which the second electromagnetic wave em2 swung in the first primary corresponding direction pcd1 is reflected by the extraction mirror 25. As shown in Fig. 7 , the second detection element 27 may have, for example, a slit plate 28 between it and the extraction mirror 25. In a configuration in which the second detection element 27 is rod-shaped, the slit plate 28 may not be provided. The rod-shaped second detection element 27 may be arranged so as to be inclined with respect to both the first secondary corresponding direction scd1 and the second secondary corresponding direction scd2.

[0045] 8 , the slit plate 28 may have a slit sl formed therein that is inclined with respect to both the first secondary corresponding direction scd1 and the second secondary corresponding direction scd2. The first secondary corresponding direction scd1 and the second secondary corresponding direction scd2 are directions corresponding to the first primary corresponding direction pcd1 and the second primary corresponding direction pcd2 of the second electromagnetic wave em2, respectively, reflected by the extraction mirror 25. The second detecting element 27 may detect the second electromagnetic wave em2 passing through the slit sl. The second detecting element 27 may transmit a detection signal to the control unit 14 when detecting the second electromagnetic wave em2.

[0046] Specifically, the first detecting element 26 and the second detecting element 27 may each include a single element such as an APD (Avalanche Photodiode) or a PD (Photodiode).

[0047] The control unit 14 includes one or more processors and memory. The processor may include at least one of a general-purpose processor that loads a specific program to execute a specific function and a dedicated processor specialized for a specific process. The dedicated processor may include an application-specific integrated circuit (ASIC). The processor may include a programmable logic device (PLD). The PLD may include a field-programmable gate array (FPGA). The control unit 14 may include at least one of a system-on-a-chip (SoC) and a system in a package (SiP) in which one or more processors work together.

[0048] The control unit 14 may control the first radiation unit 12, the second radiation unit 15, and the scanning unit 19. Furthermore, the control unit 14 may generate three-dimensional position information of an arbitrary object point on the target ob based on a drive signal for controlling the scanning unit 19 and information acquired from the first detection unit 13 and the second detection unit 16.

[0049] Specifically, the control unit 14 may acquire distance information of an arbitrary object point on the target ob by ToF (Time of Flight) based on the time when the first emitting unit 12 emits the pulsed first electromagnetic wave em1 and the time when the first detecting unit 13 detects the first electromagnetic wave em1 after emission.

[0050] Furthermore, the control unit 14 may calculate the deflection direction of the first electromagnetic wave em1 based on the drive signal to the scanning unit 19 and the detection signal (detection result) obtained from the second detecting unit 16. The deflection direction corresponds to the orientation of the reflecting surface at which the scanning unit 19 changes the radiation direction of the first electromagnetic wave em1 and the second electromagnetic wave em2. The control unit 14 may calculate the deflection direction of the first electromagnetic wave em1 as the direction of the first oscillation direction sd1 and second oscillation direction sd2 components. A method for calculating the deflection direction will be described in detail below.

[0051] The control unit 14 may, for example, output a sinusoidal drive signal that causes the scanning unit 19 to swing along the first swing direction sd1. The times at which the multiple first detection elements 26 detect the second electromagnetic wave em2 correspond to specific phases in the drive signal for the first swing direction sd1, in other words, specific deflection directions in the first primary corresponding direction PCD1. Therefore, the control unit 14 may identify the time at which the scanning unit 19 deflects in a specific direction in the first primary corresponding direction PCD1 based on the phase correspondence and the detection signals acquired from the first detection elements 26. Furthermore, the control unit 14 may estimate the deflection direction in the first primary corresponding direction PCD1 based on the time at which the scanning unit 19 deflects in a specific direction in the first primary corresponding direction PCD1, the elapsed time since the most recent detection signal was acquired, and the drive signal. The control unit 14 may estimate the deflection direction in the first swing direction sd1 based on the deflection direction in the first primary corresponding direction PCD1.

[0052] The control unit 14 may, for example, output a sinusoidal drive signal that causes the scanning unit 19 to swing along the second swing direction sd2. The interval between two points in time at which the second detecting element 27 consecutively detects the second electromagnetic wave em2 corresponds to a specific phase of the drive signal in the second swing direction sd2, in other words, a specific direction in the second secondary corresponding direction scd2. As described above, since the slit sl is inclined with respect to the second secondary corresponding direction scd2, the specific direction along the second secondary corresponding direction scd2 changes depending on the deflection direction in the first secondary corresponding direction scd1. Therefore, the control unit 14 may identify the point in time at which the scanning unit 19 is deflected in a specific direction in the second secondary corresponding direction scd2 based on the correspondence relationship with the phase based on the deflection direction in the first primary corresponding direction scd1 and the detection signal acquired from the second detecting element 27. Furthermore, the control unit 14 may estimate the deflection direction in the second secondary corresponding direction scd2 based on the time point at which the deflection occurs in a specific direction in the second secondary corresponding direction scd2, the elapsed time from the time point at which the detection signal is acquired, and the drive signal. The control unit 14 may estimate the deflection direction in the second oscillation direction sd2 based on the deflection direction in the second secondary corresponding direction scd2.

[0053] The control unit 14 may generate three-dimensional position information of an arbitrary object point based on the deflection direction to the object point and distance information calculated as described above.

[0054] The optical system 10 of the first embodiment configured as described above includes a first mirror 17 that is located on a radiation path of the first electromagnetic wave em1 emitted by the first radiator 12 and reflects the first electromagnetic wave em1, and a focusing optical system 18 that includes at least an optical element 22 that is located relative to the first mirror 17 in a second direction d2 that is the opposite direction to the first direction d1, which is the reflection direction of the first electromagnetic wave em1 by the first mirror 17, and at least a portion of the optical element 22 overlaps with the first mirror 17 when viewed from the first direction d1 and another portion of the optical element 22 deviates from the first mirror 17, and focuses the first electromagnetic wave em1 traveling in the second direction d2. In an optical system that uses a half mirror to align the propagation axes of a radiation wave emitted from a radiation source and a reflected wave of an irradiation wave from an irradiation target, a portion of the radiation wave is lost when the radiation wave from the radiation source is reflected by the half mirror, and further a portion of the reflected wave is lost when the reflected wave from the irradiation target is transmitted through the half mirror. Therefore, the optical system has a low measurement sensitivity. On the other hand, in the optical system 10 having the above-described configuration, only a portion of the first optical element 22 overlaps with the first mirror 17 for aligning the propagation axes, and therefore, it is possible to achieve alignment of the propagation axes and reduce loss of the first electromagnetic wave em1 even while using the first mirror 17 with high reflectivity.

[0055] Furthermore, in the optical system 10, the first optical element 22 is larger than the first mirror 17 when viewed from the first direction d1. With this configuration, the optical system 10 can reduce loss caused by the first mirror 17 when the first electromagnetic wave em1 reflected by the object ob is transmitted to the first optical element 22.

[0056] The optical system 10 further includes a second mirror 20 located on a radiation path of the second electromagnetic wave em2 emitted by the second radiation unit 15, which radiates a second electromagnetic wave em2 in a band different from the first electromagnetic wave em1, the second mirror 20 transmitting the first electromagnetic wave em1 and reflecting the second electromagnetic wave em2, and a third mirror 21 located closer to the object side than the scanning unit 19 and transmitting the first electromagnetic wave em1 and reflecting the second electromagnetic wave em2. With this configuration, the optical system 10 can calculate the deflection direction of the first electromagnetic wave em1 by the scanning unit 19 by detecting the second electromagnetic wave em2 by the third mirror 21.

[0057] Next, an optical system according to a second embodiment of the present disclosure will be described. In the second embodiment, the structure of the focusing optical system is different from that of the first embodiment. The second embodiment will be described below, focusing on the differences from the first embodiment. Note that parts having the same configuration as those in the first and second embodiments will be denoted by the same reference numerals.

[0058] 9 , the optical system 100 according to the second embodiment includes a first mirror 17 and a focusing optical system 180, similar to the first embodiment. The optical system 100 may further include a scanning unit 19, a second mirror 200, and a third mirror 21, similar to the first embodiment. Unlike the first embodiment, the optical system 100 may further include an imaging optical system 290. In the second embodiment, the configurations of the first mirror 17, the scanning unit 19, and the third mirror 21 are the same as those in the first embodiment.

[0059] Similar to the first embodiment, the focusing optical system 180 is positioned in the second direction d2 relative to the first mirror 17. Similar to the first embodiment, the focusing optical system 180 focuses the first electromagnetic wave em1 traveling in the second direction d2. Similar to the first embodiment, the focusing optical system 180 includes at least a first optical element 220. Similar to the first embodiment, the focusing optical system 180 further includes a light-guiding optical system 230.

[0060] Similar to the first embodiment, the first optical element 220 has at least a portion that overlaps with the first mirror 17 and another portion that is outside the first mirror 17 when viewed from the first direction d1. Similar to the first embodiment, the first optical element 220 may be larger than the first mirror 17 when viewed from the first direction d1. Similar to the first embodiment, the first optical element 220 may include the first mirror 17 when viewed from the first direction d1. Similar to the first embodiment, the first optical element 220 may be a concave mirror. Unlike the first embodiment, the first optical element 220 that is a concave mirror may not have a hole that at least a portion of which overlaps with the light-guiding optical system 230 when viewed from the first direction d1. The first optical element 220 may reflect the second electromagnetic wave em2.

[0061] Unlike the first embodiment, the light-guiding optical system 230 may include a fourth mirror 300 and a fifth mirror 310 .

[0062] The fourth mirror 300, which is a fourth optical member, may be located between the first mirror 17 and the first optical element 220. The fourth mirror 300 may be located closer to the first optical element 22 than the focal point of the first optical element 220. The fourth mirror 300 may be a convex mirror. As shown in FIG. 10 , the fourth mirror 300 may reflect the first electromagnetic wave em1 reflected from the first optical element (concave mirror) 220. The fourth mirror 300 may reflect the second electromagnetic wave em2 reflected from the second mirror 200.

[0063] The fifth mirror 310, which is a fifth optical element, may be located in the second direction d2 from the fourth mirror 300. The fifth mirror 310 may be located on the first direction d1 side of the position where the first electromagnetic wave em1 traveling from the first optical element 220 toward the focal point is focused by the fourth mirror 300. The fifth mirror 310 may reflect the first electromagnetic wave em1 reflected by the fourth mirror 300 in a third direction d3. In the second embodiment, the third direction d3 may be a direction intersecting the first direction d1. As shown in FIG. 9 , the fifth mirror 310 may transmit the second electromagnetic wave em2.

[0064] Similar to the first embodiment, the second mirror 200 may be located at an intersection of the radiation path of the second electromagnetic wave em2 from the second radiating unit 15 and the position toward the second direction d2 from the fifth mirror 310. The second mirror 200 may reflect the second electromagnetic wave em2 in the first direction d1.

[0065] The imaging optical system 290 may be located in the direction in which the second electromagnetic wave em2 is reflected by the third mirror 21. The imaging optical system 290 may form an image of the incident second electromagnetic wave em2.

[0066] The optical system 100 of the second embodiment configured as described above also includes a first mirror 17 that is located on the radiation path of the first electromagnetic wave em1 from the first radiator 12 and reflects the first electromagnetic wave em1, and a focusing optical system 180 that includes at least an optical element 220 that is located relative to the first mirror 17 in a second direction d2 that is the opposite direction to the first direction d1 in which the first electromagnetic wave em1 is reflected by the first mirror 17, and that at least partially overlaps with the first mirror 17 and another partially deviates from the first mirror 17 when viewed from the first direction d1, and that focuses the first electromagnetic wave em1 traveling in the second direction d2. Therefore, the optical system 100 can also achieve coincidence of the propagation axes and reduction of loss of the first electromagnetic wave em1, while using the first mirror 17 with high reflectivity.

[0067] Also in the optical system 100, the first optical element 220 is larger than the first mirror 17 when viewed from the first direction d1. Therefore, the optical system 100 can also reduce loss caused by the first mirror 17 in the transmission of the first electromagnetic wave em1 reflected by the object ob to the first optical element 220.

[0068] Furthermore, in the optical system 100, the light-guiding optical system 230 includes a fourth mirror 300 that reflects the first electromagnetic wave em1 reflected from the first optical element (concave mirror) 220, and a fifth mirror 310 that is positioned in the second direction d2 from the fourth mirror 300 and reflects the first electromagnetic wave em1 reflected by the fourth mirror 300 in a third direction d3, where the third direction d3 intersects with the first direction d1. With this configuration, the optical system 100 can have a shorter focal length than the first embodiment. Therefore, the optical system 100 can increase the scanning speed of the scanning unit 19.

[0069] The optical system 100 further includes a second mirror 200 that is located at an intersection of an emission path of the second electromagnetic wave em2 emitted by the second emitter 15, which emits a second electromagnetic wave em2 in a band different from the first electromagnetic wave em1, and a position toward the second direction d2 from the fifth mirror 310, and that reflects the second electromagnetic wave em2 in the first direction d1, and a third mirror 21 that is provided closer to the object than the scanning unit 19 and transmits the first electromagnetic wave em1 and reflects the second electromagnetic wave em2, the fifth mirror 310 transmitting the second electromagnetic wave em2. With this configuration, the optical system 100 can calculate the deflection direction of the first electromagnetic wave em1 by the scanning unit 19 by detecting the second electromagnetic wave em2 by the third mirror 21.

[0070] The optical system 100 also includes an imaging optical system 290 located in the direction of reflection of the second electromagnetic wave em2 by the third mirror 21, which forms an image of the incident second electromagnetic wave em2. With the second emitting unit 15, second mirror 200, first optical element 220, fourth mirror 300, and fifth mirror 310 configured as described above, the second electromagnetic wave em2 can be a beam with a large diameter. If the diameter of the second electromagnetic wave em2 is large, the measurement accuracy of the deflection direction using the second detecting unit 16 decreases. On the other hand, the optical system 100 configured as described above focuses the beam of the second electromagnetic wave em2 with a large diameter, thereby maintaining high measurement accuracy of the deflection direction.

[0071] Next, an optical system according to a third embodiment of the present disclosure will be described. In the third embodiment, the structure of the light-guiding optical system is different from that of the first embodiment. The third embodiment will be described below, focusing on the differences from the first embodiment. Note that parts having the same configuration as those in the first embodiment will be assigned the same reference numerals.

[0072] 11 , an optical system 101 according to the third embodiment, similar to the first embodiment, includes a first mirror 17 and a focusing optical system 181. Similar to the first embodiment, the optical system 101 may further include a scanning unit 19 and a third mirror 21. In the third embodiment, the configurations of the first mirror 17, scanning unit 19, and third mirror 21 are the same as those in the first embodiment.

[0073] The focusing optical system 181 is located in the second direction d2 relative to the first mirror 17, as in the first embodiment. The focusing optical system 181 focuses the first electromagnetic wave em1 traveling in the second direction d2, as in the first embodiment. The focusing optical system 181 includes at least a first optical element 220, as in the first embodiment. The focusing optical system 181 further includes a light-guiding optical system 231, as in the first embodiment. The configuration of the first optical element 220 is the same as in the second embodiment.

[0074] Unlike the first embodiment, the light-guiding optical system 231 may have a single reflecting mirror 321. As shown in Fig. 12, the single reflecting mirror 321 may reflect the first electromagnetic wave em1 reflected from the first optical element 220, which is a concave mirror, in a third direction d3. In the third embodiment, the third direction d3 may be a direction intersecting the first direction d1.

[0075] 11 , the reflecting mirror 321 may be located on the radiation path of the second electromagnetic wave em2 emitted by the second radiator 15. The reflecting mirror 321 may reflect the incident second electromagnetic wave em2 in the first direction d1. Specifically, the surface of the reflecting mirror 321 opposite to the surface that reflects the first electromagnetic wave em1 emitted from the first optical element 220 may function as the second mirror 20 in the first embodiment. Note that in the third embodiment, the first mirror 17 may transmit the second electromagnetic wave em2.

[0076] The optical system 101 of the third embodiment configured as described above also includes a first mirror 17 that is located on the radiation path of the first electromagnetic wave em1 from the first radiator 12 and reflects the first electromagnetic wave em1, and a focusing optical system 181 that includes at least an optical element 220 that is located relative to the first mirror 17 in a second direction d2 that is the opposite direction to the first direction d1 in which the first electromagnetic wave em1 is reflected by the first mirror 17, and that at least partially overlaps with the first mirror 17 and another partially deviates from the first mirror 17 when viewed from the first direction d1, and that focuses the first electromagnetic wave em1 traveling in the second direction d2. Therefore, the optical system 101 can also achieve coincidence of the propagation axes and reduction of loss of the first electromagnetic wave em1, while using a first mirror 17 with high reflectivity.

[0077] Also in the optical system 101, the first optical element 220 is larger than the first mirror 17 when viewed from the first direction d1. Therefore, the optical system 101 can also reduce loss caused by the first mirror 17 in the transmission of the first electromagnetic wave em1 reflected by the object ob to the first optical element 220.

[0078] Furthermore, in the optical system 101, the light-guiding optical system 231 is a single reflecting mirror 321 that reflects the first electromagnetic wave em1 reflected from the first optical element (concave mirror) 220 in a third direction d3, and the third direction d3 is a direction that intersects with the first direction d1. With this configuration, the optical system 101 can have a shorter focal length than the first embodiment. Therefore, the optical system 101 can increase the scanning speed of the scanning unit 19.

[0079] The optical system 101 further includes a third mirror 21 that is disposed closer to the object than the scanning unit 19 and transmits the first electromagnetic wave em1, and the single reflecting mirror 321 is located on a radiation path of the second electromagnetic wave em2 emitted by the second radiating unit 15 that radiates the second electromagnetic wave em2 in a band different from the first electromagnetic wave em1, and reflects the second electromagnetic wave em2 in the first direction d1, while the first mirror 17 transmits the second electromagnetic wave em2. With this configuration, the optical system 101 can calculate the deflection direction of the first electromagnetic wave em1 emitted by the scanning unit 19 by detecting the second electromagnetic wave em2 with the third mirror 21.

[0080] Next, an optical system according to a fourth embodiment of the present disclosure will be described. In the fourth embodiment, the structure of the light-guiding optical system is different from that of the first embodiment. Below, the third embodiment will be described, focusing on the differences from the first embodiment. Note that parts having the same configuration as those in the first and second embodiments will be assigned the same reference numerals.

[0081] 13 , the optical system 102 according to the fourth embodiment is similar to the first embodiment and includes a first mirror 172 and a focusing optical system 182. Similarly to the first embodiment, the optical system 101 may further include a scanning unit 19, a second mirror 20, and a third mirror 21. In the third embodiment, the configurations of the scanning unit 19, the second mirror 20, and the third mirror 21 are the same as those in the first embodiment.

[0082] As in the first embodiment, the first mirror 172 is located on the radiation path of the first electromagnetic wave em1 emitted by the first radiator 12. As in the first embodiment, the first mirror 172 reflects the first electromagnetic wave em1 in the first direction d1. Unlike the first embodiment, the first mirror 172 may function as a reflecting mirror 322, which will be described later. Specifically, the first mirror 172 may function as a reflecting mirror 322, which will be described later, on the back side of the surface of the first mirror 172 that reflects the first electromagnetic wave em1 emitted by the first radiator 12.

[0083] The focusing optical system 182 is located in the second direction d2 relative to the first mirror 172, as in the first embodiment. The focusing optical system 182 focuses the first electromagnetic wave em1 traveling in the second direction d2, as in the first embodiment. The focusing optical system 182 includes at least a first optical element 220, as in the first embodiment. The focusing optical system 182 further includes a light-guiding optical system 232, as in the first embodiment. The configuration of the first optical element 220 is the same as in the second embodiment.

[0084] The light-guiding optical system 232 may have a single reflecting mirror 322, similar to the third embodiment. As in the third embodiment, the single reflecting mirror 322 may reflect the first electromagnetic wave em1 reflected from the first optical element 220, which is a concave mirror, in the third direction d3. In the fourth embodiment, the third direction d3 may be a direction intersecting the first direction d1, similar to the third embodiment.

[0085] The optical system 102 of the fourth embodiment configured as described above also includes a first mirror 172 that is located on the radiation path of the first electromagnetic wave em1 from the first radiator 12 and reflects the first electromagnetic wave em1, and a focusing optical system 182 that includes at least an optical element 220 that is located relative to the first mirror 172 in a second direction d2 that is the opposite direction to the first direction d1 in which the first electromagnetic wave em1 is reflected by the first mirror 172, and that at least partially overlaps with the first mirror 172 and another partially deviates from the first mirror 172 when viewed from the first direction d1, and that focuses the first electromagnetic wave em1 traveling in the second direction d2. Therefore, the optical system 102 can also achieve coincidence of the propagation axes and reduction of loss of the first electromagnetic wave em1 while using the first mirror 172 with high reflectivity.

[0086] Also in the optical system 102, the first optical element 220 is larger than the first mirror 172 when viewed from the first direction d1. Therefore, the optical system 102 can also reduce loss caused by the first mirror 172 in the transmission of the first electromagnetic wave em1 reflected by the object ob to the first optical element 220.

[0087] Also in the optical system 102, the light-guiding optical system 232 is a single reflecting mirror 322 that reflects the first electromagnetic wave em1 reflected from the first optical element (concave mirror) 220 in a third direction d3, and the third direction d3 is a direction that intersects with the first direction d1. With this configuration, the optical system 102 can have a shorter focal length than the first embodiment. Therefore, the optical system 102 can increase the scanning speed of the scanning unit 19.

[0088] Furthermore, in the optical system 102, the first mirror 172 functions as the single reflecting mirror 322. With this configuration, the optical system 102 shares the first mirror 172 as the reflecting mirror 322, which simplifies the configuration and reduces manufacturing costs.

[0089] In one embodiment, (1) the optical system includes: a first optical member that causes a first electromagnetic wave emitted from a first radiating portion to travel in a first direction; and a focusing optical system that includes an optical element onto which the first electromagnetic wave is reflected by an object and upon which a reflected wave that has passed through a predetermined region including the first optical member is incident, and that focuses the first electromagnetic wave that has incident on the optical element.

[0090] (2) The optical system of (1) above further includes a scanning unit that changes the radiation direction of the first electromagnetic wave traveling in the first direction and causes the reflected wave of the radiated first electromagnetic wave reflected by the object to travel to the optical element.

[0091] (3) In the optical system of (1) or (2) above, the optical element is a concave mirror, and the focusing optical system further includes a light-guiding optical system that guides the reflected wave reflected from the concave mirror in a third direction.

[0092] (4) In any of the optical systems (1) to (3) above, the concave mirror has a hole that at least partially overlaps with the light-guiding optical system when viewed from the first direction and allows the first electromagnetic wave guided by the light-guiding optical system to pass through.

[0093] (5) The optical system of (2) above further includes a second optical element that transmits a second electromagnetic wave in a band different from the first electromagnetic wave emitted from the second radiation element in the first direction and transmits the first electromagnetic wave; and a third optical element that is provided closer to the object side than the scanning element, transmits the first electromagnetic wave, and changes the direction of propagation of the second electromagnetic wave, and the second optical element is located between the first optical element and the scanning element.

[0094] (6) In any of the optical systems (1) to (5) above, the optical system further includes: a second optical element that changes the direction of propagation of a second electromagnetic wave in a band different from the first electromagnetic wave emitted from the second radiating unit and transmits the first electromagnetic wave; and a third optical element that is provided on the object side of the scanning unit and transmits the first electromagnetic wave and changes the direction of propagation of the second electromagnetic wave, and the second optical element is located on the propagation path of the first electromagnetic wave from the first radiating unit to the first optical element.

[0095] (7) Any of the optical systems (1) to (6) above further includes a second optical element that changes the direction of propagation of a second electromagnetic wave in a band different from the first electromagnetic wave emitted from the second radiation unit and transmits the first electromagnetic wave; and a third optical element that is provided closer to the object than the scanning unit and transmits the first electromagnetic wave and changes the direction of propagation of the second electromagnetic wave, wherein the second optical element is located in a second direction opposite to the first direction from the light-guiding optical system, and the first optical element and the light-guiding optical system transmit the second electromagnetic wave.

[0096] (8) In the optical system of (1) to (7) above, the light-guiding optical system has a fourth optical element that changes the direction of travel of the first electromagnetic wave reflected by the concave mirror, and a fifth optical element that is located in a second direction opposite to the first direction from the fourth optical element and causes the first electromagnetic wave, whose direction of travel has been changed by the fourth optical element, to travel in the third direction, and the third direction is a direction that intersects with the first direction.

[0097] (9) The optical system of (1) to (8) above further includes: a second optical element located at an intersection of a radiation path of a second electromagnetic wave in a band different from the first electromagnetic wave radiated from the second radiation unit and a position toward the second direction from the fifth optical element, and causing the second electromagnetic wave to travel in the first direction; and a third optical element located closer to the object than the scanning unit, transmitting the first electromagnetic wave and changing the traveling direction of the second electromagnetic wave, wherein the fifth optical element transmits the second electromagnetic wave.

[0098] (10) In the optical system of (1) to (9) above, the light-guiding optical system is a single reflecting mirror that reflects the first electromagnetic wave from the concave mirror in the third direction, and the third direction is a direction that intersects with the first direction.

[0099] (11) In the optical system according to any one of (1) to (10) above, the first optical member functions as the single reflecting mirror.

[0100] (12) Any of the optical systems (1) to (11) above further includes a third optical element disposed closer to the object than the scanning unit and transmitting the first electromagnetic wave, wherein the single reflecting mirror is located on a radiation path of the second electromagnetic wave emitted by a second radiation unit that radiates a second electromagnetic wave in a band different from the first electromagnetic wave, and reflects the second electromagnetic wave in the first direction, and the first optical element transmits the second electromagnetic wave.

[0101] In one embodiment, (13) the optical system of (5) above is provided, a first detection unit that detects the first electromagnetic wave traveling in the third direction, a second detection unit that detects the second electromagnetic wave traveling from the third optical element, and a control unit that detects the orientation of a reflecting surface that changes the radiation direction of the first electromagnetic wave and the second electromagnetic wave based on the detection result of the second detection unit.

[0102] Although the embodiments of the optical systems 10, 100, 101, and 102 have been described above, the drawings illustrating the embodiments according to the present disclosure are schematic. The dimensional ratios and the like in the drawings do not necessarily correspond to the actual ones.

[0103] Although the embodiments of the present disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art could make various modifications or alterations based on the present disclosure. Therefore, it should be noted that these modifications or alterations are included in the scope of the present disclosure. For example, the functions included in each component can be rearranged so as not to cause logical inconsistencies, and multiple components can be combined or divided into one.

[0104] For example, in the above-described embodiments, the focusing optical system 18, 180, 181, 182 includes the first optical element 22, which is a concave mirror, and the light-guiding optical system 23, 230, 231, 232. However, the focusing optical system is not limited to this configuration. For example, the first electromagnetic wave em1 may be focused using a convex lens without including the light-guiding optical system.

[0105] For example, in the above embodiment, the optical system 10 is configured to include the first mirror 17, but is not limited to such a configuration. In the above embodiment, for the first mirror 17 that is not configured to transmit or reflect the second electromagnetic wave em2, the first radiator 12 may be disposed at the position where the first mirror 17 is disposed. The first radiator 12 may radiate the first electromagnetic wave em1 in a first direction.

[0106] For example, in the above embodiment, the first mirror 17 is disposed at a position that is the center of the scanning unit 19 in a direction intersecting the first direction d1 and the second direction d2 as shown in the figure, but is not limited to this configuration. For example, the first mirror 17 may be disposed so as to be shifted a predetermined amount from the center of the scanning unit 19 in the intersecting direction. Similarly, the second mirror 20, which is disposed at a position that is the center of the scanning unit 19 in the intersecting direction as shown in the figure, may also be disposed so as to be shifted a predetermined amount from the center of the scanning unit 19 in the intersecting direction.

[0107] For example, in the above embodiment, the hole h1 is configured to at least partially overlap with the light-guiding optical system 23 when viewed from the first direction d1, but this configuration is not limiting. For example, the hole h1 may be configured not to overlap with the light-guiding optical system 23 when viewed from the first direction d1. In this case, the light-guiding optical system 23 may be an optical system that allows the first electromagnetic wave em1 from the first optical element 22, which is a concave mirror, to travel to the hole h1.

[0108] For example, in the above embodiment, the third mirror 21 is configured to transmit the first electromagnetic wave em1 and reflect the second electromagnetic wave em2, but is not limited to such a configuration. For example, the third mirror 21 may be configured to reflect the first electromagnetic wave em1 and transmit the second electromagnetic wave em2. In this case, the second detector 16 may be provided in the traveling direction of the second electromagnetic wave em2.

[0109] For example, in the above embodiment, a portion of the reflected light of the first electromagnetic wave em1 reflected by the object ob is blocked by the first mirror 17, which may affect the accuracy of the distance information when the control unit 14 acquires distance information of an arbitrary object point on the object ob. Therefore, for example, when acquiring distance information of an arbitrary object point on the object ob, the control unit 14 may predict the intensity of the reflected light of the first electromagnetic wave em1 reflected by the object ob based on a Gaussian distribution or the like, and acquire the distance information of the arbitrary object point from the predicted intensity of the reflected light.

[0110] All of the features described in this disclosure and / or all steps of all of the disclosed methods or processes may be combined in any combination except combinations in which these features are mutually exclusive. Furthermore, each feature described in this disclosure may be replaced by an alternative feature serving the same, equivalent, or similar purpose, unless expressly denied. Thus, unless expressly denied, each disclosed feature is only one example of a generic series of identical or equivalent features.

[0111] Furthermore, embodiments of the present disclosure are not limited to the specific configurations of any of the above-described embodiments, but rather extend to any novel feature or combination thereof described herein, or any novel method or process step or combination thereof described herein.

[0112] In the present disclosure, descriptions such as "first" and "second" are identifiers for distinguishing the configuration. In the present disclosure, the configurations distinguished by descriptions such as "first" and "second" can have their numbers interchanged. For example, the first electromagnetic wave can have its identifiers "first" and "second" interchanged with the second electromagnetic wave. The identifiers are interchanged simultaneously. The configurations remain distinguished even after the identifiers are interchanged. The identifiers may be deleted. A configuration from which the identifiers have been deleted is distinguished by a symbol. The identifiers "first" and "second" in the present disclosure should not be used solely to interpret the order of the configurations or to justify the existence of an identifier with a smaller number.

[0113] 10, 100, 101 Optical system 11 Electromagnetic wave detection device 12 First radiation unit 13 First detection unit 14 Control unit 15 Second radiation unit 16 Second detection unit 17 First mirror 18, 180, 181 Focusing optical system 19 Scanning unit 20, 200 Second mirror 21 Third mirror 22, 220 First optical element 23, 230, 231 Light-guiding optical system 24 Second optical element 25 Extraction mirror 26 First detection element 27 Second detection element 28 Slit plate 290 Imaging optical system 300 Fourth mirror 310 Fifth mirror 321 Reflecting mirror d1 First direction d2 Second direction d3 Third direction em1 First electromagnetic wave em2 Second electromagnetic wave hl Hole portion ob Object

Claims

1. An optical system comprising: a first optical element that causes a first electromagnetic wave emitted from a first radiator to travel in a first direction; and a focusing optical system that includes an optical element onto which the first electromagnetic wave is reflected by an object and passes through a predetermined area including the first optical element, and that focuses the first electromagnetic wave that has entered the optical element.

2. An optical system according to claim 1, further comprising a scanning unit that changes the radiation direction of the first electromagnetic wave traveling in the first direction, and causes the reflected wave of the radiated first electromagnetic wave reflected by the object to travel to the optical element.

3. An optical system according to claim 2, wherein the optical element is a concave mirror, and the focusing optical system further includes a light-guiding optical system that guides the reflected wave reflected from the concave mirror in a third direction.

4. An optical system according to claim 3, wherein the concave mirror has a hole that at least partially overlaps with the light-guiding optical system when viewed from the first direction and that allows the first electromagnetic wave guided by the light-guiding optical system to pass through.

5. An optical system as described in claim 4, further comprising: a second optical element that transmits a second electromagnetic wave in a band different from the first electromagnetic wave emitted from the second radiation element in the first direction and transmits the first electromagnetic wave; and a third optical element that is provided closer to the object side than the scanning element, transmits the first electromagnetic wave, and changes the direction of propagation of the second electromagnetic wave, wherein the second optical element is located between the first optical element and the scanning element.

6. An optical system as claimed in claim 4, further comprising: a second optical element that changes the direction of travel of a second electromagnetic wave in a band different from the first electromagnetic wave emitted from the second radiating element and transmits the first electromagnetic wave; and a third optical element that is provided closer to the object side than the scanning element and transmits the first electromagnetic wave and changes the direction of travel of the second electromagnetic wave, wherein the second optical element is located on the travel path of the first electromagnetic wave from the first radiating element to the first optical element.

7. An optical system as described in claim 4, further comprising: a second optical element that changes the direction of propagation of a second electromagnetic wave in a band different from the first electromagnetic wave radiated from the second radiation element and transmits the first electromagnetic wave; and a third optical element that is provided closer to the object side than the scanning element and transmits the first electromagnetic wave and changes the direction of propagation of the second electromagnetic wave, wherein the second optical element is located in a second direction opposite to the first direction from the light-guiding optical system, and the first optical element and the light-guiding optical system transmit the second electromagnetic wave.

8. An optical system according to claim 3, wherein the light-guiding optical system has a fourth optical element that changes the direction of travel of the first electromagnetic wave reflected by the concave mirror, and a fifth optical element that is located in a second direction opposite to the first direction from the fourth optical element and causes the first electromagnetic wave, whose direction of travel has been changed by the fourth optical element, to travel in the third direction, and the third direction is a direction that intersects with the first direction.

9. An optical system as described in claim 8, further comprising: a second optical element located at an intersection of a radiation path of a second electromagnetic wave in a band different from the first electromagnetic wave radiated from the second radiation unit and a position from the fifth optical element toward the second direction, and causing the second electromagnetic wave to travel in the first direction; and a third optical element located closer to the object than the scanning element, transmitting the first electromagnetic wave and changing the direction of travel of the second electromagnetic wave, wherein the fifth optical element transmits the second electromagnetic wave.

10. An optical system according to claim 3 or 4, wherein the light-guiding optical system is a single reflecting mirror that reflects the first electromagnetic wave from the concave mirror in the third direction, and the third direction is a direction that intersects with the first direction.

11. An optical system according to claim 10, wherein the first optical member functions as the single reflecting mirror.

12. An optical system as described in claim 10, further comprising a third optical element disposed closer to the object than the scanning element and transmitting the first electromagnetic wave, wherein the single reflecting mirror is located on a radiation path of the second electromagnetic wave emitted by a second radiation element that radiates a second electromagnetic wave in a band different from the first electromagnetic wave, and reflects the second electromagnetic wave in the first direction, and the first optical element is transmitting the second electromagnetic wave.

13. An electromagnetic wave detection device comprising: an optical system according to any one of claims 5 to 7, 9 and 12; a first detection unit that detects the first electromagnetic wave traveling in the third direction; a second detection unit that detects the second electromagnetic wave traveling from the third optical element; and a control unit that detects the orientation of a reflecting surface that causes the scanning unit to change the radiation direction of the first electromagnetic wave and the second electromagnetic wave based on the detection result of the second detection unit.

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