Electromagnetic wave radiation device

Abstract

An electromagnetic wave radiation device 1 includes: a radiation part 11 for radiating an electromagnetic wave L1; a second detection part 82 for detecting the electromagnetic wave L1; a change part 40 for changing the radiation direction of the electromagnetic wave L1 radiated by the radiation part 11 along a first direction D1 and a second direction D2 intersecting the first direction D1; and a branching part 50b for guiding, to the second detection part 82, a portion of the electromagnetic wave L1 of which the radiation direction is changed by the change part 40.

Description

Electromagnetic wave irradiation device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Japanese Patent Application No. 2023-193100, filed on November 13, 2023, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to an electromagnetic wave irradiation device.

[0003] In recent years, devices have been developed that acquire information about surrounding objects and the like from the results of detecting electromagnetic waves. For example, Patent Literature 1 discloses a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) system that can reduce distortion of the illumination field.

[0004] Japanese Patent Application Laid-Open No. 2022-059924

[0005] In order to solve the above-mentioned problems, an electromagnetic wave irradiation device according to a first aspect includes an irradiation unit that irradiates electromagnetic waves, and a second detection unit that detects the electromagnetic waves. The electromagnetic wave irradiation device includes a change unit that changes the irradiation direction of the electromagnetic waves irradiated by the irradiation unit along a first direction and a second direction intersecting the first direction. The electromagnetic wave irradiation device includes a branching unit that guides a portion of the electromagnetic waves, the irradiation direction of which has been changed by the change unit, to the second detection unit.

[0006] Fig. 1 is a first perspective view showing a schematic configuration of an electromagnetic wave irradiation device according to a first embodiment of the present disclosure. Fig. 2 is a second perspective view showing a schematic configuration of an electromagnetic wave irradiation device according to a first embodiment of the present disclosure. Fig. 3 is a third perspective view showing a schematic configuration of an electromagnetic wave irradiation device according to a first embodiment of the present disclosure. Fig. 4 is a schematic view of a first detection unit in Fig. 1 when viewed in the traveling direction of a first electromagnetic wave. Fig. 5 is a schematic view of a second detection unit in Fig. 3 when viewed in the traveling direction of a first electromagnetic wave. Fig. 6 is a perspective view showing a schematic configuration of an electromagnetic wave irradiation device according to a second embodiment of the present disclosure.

[0007] For example, in a LIDAR system, detecting the direction in which electromagnetic waves are irradiated onto surrounding objects is useful for improving the measurement accuracy of the LIDAR system.

[0008] According to an electromagnetic wave irradiation device according to an embodiment of the present disclosure, it is possible to detect the irradiation direction of the irradiated electromagnetic waves.

[0009] Hereinafter, one embodiment of the present disclosure will be mainly described with reference to the accompanying drawings.

[0010] (First embodiment) Fig. 1 is a first perspective view showing a schematic configuration of an electromagnetic wave irradiation device 1 according to a first embodiment of the present disclosure. Fig. 2 is a second perspective view showing a schematic configuration of the electromagnetic wave irradiation device 1 according to the first embodiment of the present disclosure. Fig. 3 is a third perspective view showing a schematic configuration of the electromagnetic wave irradiation device 1 according to the first embodiment of the present disclosure. Only the configurations of different parts of the electromagnetic wave irradiation device 1 are shown between Figs. 1, 2, and 3. Between Figs. 1 and 2, a first electromagnetic wave L1 and a second electromagnetic wave L2 that are irradiated at the same time by the electromagnetic wave irradiation device 1 are shown separately for ease of understanding. An example of the configuration and function of the electromagnetic wave irradiation device 1 according to the first embodiment will be mainly described with reference to Figs. 1 to 3.

[0011] 1 to 3, the electromagnetic wave irradiation device 1 according to the first embodiment has an irradiation section 10, a parallel section 20, a combining section 30, a changing section 40, a first branching section 50a, a second branching section 50b, a waveguide section 60, a focusing section 70, a detection section 80, and a control section 90. The electromagnetic wave irradiation device 1 according to the first embodiment may have all of these components, or may further have components other than these components, or may not have some of these components as long as the functions of the electromagnetic wave irradiation device 1 can be realized.

[0012] 1 to 3, the above-mentioned components are arranged at sufficient distances from one another for the sake of convenience of explanation. However, when the electromagnetic wave irradiation device 1 according to the first embodiment is actually configured as an apparatus, the components constituting the electromagnetic wave irradiation device 1 may be arranged more densely than in the state shown in FIGS. 1 to 3. For example, the components may be arranged so that the electromagnetic wave irradiation device 1 is configured to be small enough to fit within an area of ​​several centimeters square. It should be noted that the scale of the electromagnetic wave irradiation device 1 shown in FIGS. 1 to 3 is a functional concept and differs from the actual scale of the electromagnetic wave irradiation device 1.

[0013] 1 to 3, bundles of solid lines overlapping each component represent the beam-like first electromagnetic wave L1 or the second electromagnetic wave L2. In Figures 1 and 2, three bundles of solid lines are shown downstream of the changing unit 40, and each of the three bundles of solid lines represents the beam-like first electromagnetic wave L1 or the second electromagnetic wave L2. Each of the three bundles of solid lines represents the electromagnetic wave at a different time when the irradiation direction of the electromagnetic wave is changed by the changing unit 40.

[0014] 1 to 3 may be communicably connected by wire or wirelessly to various other components that control and / or drive the respective components as appropriate. For example, the irradiation unit 10, the change unit 40, and the detection unit 80 are communicably connected by wire or wirelessly to the control unit 90. The dashed lines in FIGS. 1 to 3 indicate control lines for controlling the respective components by the control unit 90.

[0015] Each component shown in Figures 1 to 3 may be connected to other components that supply power to the corresponding component, as appropriate. For ease of explanation, other components that supply power to the corresponding component are omitted from Figures 1 to 3. Each component shown in Figures 1 to 3 may be fixed and / or positioned at each position shown in Figures 1 to 3, as appropriate. For ease of explanation, various members that fix and / or position each component are omitted from Figures 1 to 3.

[0016] As will be described in further detail below, the electromagnetic wave irradiation device 1 according to the first embodiment irradiates electromagnetic waves and outputs the irradiated electromagnetic waves while changing (deflecting) the irradiation direction. At least a portion of the electromagnetic waves whose irradiation direction has been changed by the electromagnetic wave irradiation device 1 is reflected by an object including a predetermined object. The electromagnetic waves reflected by the predetermined object are detected, for example, by an electromagnetic wave detection device paired with the electromagnetic wave irradiation device 1. The information acquisition system according to the first embodiment is configured including the electromagnetic wave irradiation device 1 according to the first embodiment and the electromagnetic wave detection device. The information acquisition system includes, for example, a ranging system.

[0017] The distance measurement system according to the first embodiment has the electromagnetic wave irradiation device 1 according to the first embodiment and measures the distance to an object. The object to be measured is an object that exists within a detection range in which the distance can be measured by the distance measurement system. The information acquisition system according to the first embodiment employs, for example, LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) technology used in "light detection and ranging" or "laser imaging detection and ranging." The information acquisition system according to the first embodiment can, for example, measure reflected light from pulsed laser irradiation light, and analyze the distance to an object located at a relatively long distance and / or the properties of the object.

[0018] The irradiation unit 10 includes a first irradiation unit 11 and a second irradiation unit 12. The first irradiation unit 11 and the second irradiation unit 12 are arranged at positions at 90° to each other with the combining unit 30 therebetween.

[0019] The first irradiating unit 11 includes, for example, a laser diode (LD) such as a semiconductor laser that functions as a laser utilizing recombination light emission of a semiconductor. Without being limited thereto, the first irradiating unit 11 may include other light-emitting elements such as a light-emitting diode (LED). The first irradiating unit 11 irradiates the first electromagnetic wave L1 as, for example, visible light. The first irradiating unit 11 irradiates the first electromagnetic wave L1 as, for example, a continuous wave (CW).

[0020] The first irradiating unit 11 irradiates, for example, a first electromagnetic wave L1 having a wavelength in the visible range as a monitor electromagnetic wave for detecting the irradiation direction of the electromagnetic wave changed by the changing unit 40, i.e., the deflection angle of the reflecting surface in the changing unit 40. The first irradiating unit 11 irradiates the first electromagnetic wave L1 toward the combining unit 30 via the parallel unit 20. Therefore, the first irradiating unit 11 is fixed and / or positioned so that the first electromagnetic wave L1 irradiated by the first irradiating unit 11 is incident on the combining unit 30 via the parallel unit 20. The first electromagnetic wave L1 is visible light, for example, red light, to improve visibility, but is not limited to this. The first electromagnetic wave L1 may also be green light or blue light.

[0021] As shown in Fig. 2, the second irradiation unit 12 has, for example, a laser diode (LD) such as a semiconductor laser that functions as a laser utilizing recombination light emission of a semiconductor. The second irradiation unit 12 may have, for example, a plurality of laser diodes arranged in an array in the electromagnetic wave irradiation device 1. The second irradiation unit 12 may have, for example, a single laser diode including a plurality of light-emitting regions arranged in an array in the electromagnetic wave irradiation device 1. The second irradiation unit 12 irradiates, for example, the second electromagnetic wave L2 as infrared light. The second irradiation unit 12 irradiates, for example, the second electromagnetic wave L2 in a pulsed form.

[0022] The second irradiating unit 12 irradiates a second electromagnetic wave L2 having a wavelength in the infrared region, for example, as an electromagnetic wave for scanning an object to be measured for distance, etc. The second irradiating unit 12 irradiates the second electromagnetic wave L2 toward the combining unit 30 via the parallel unit 20. Therefore, the second irradiating unit 12 is fixed and / or positioned such that the second electromagnetic wave L2 irradiated by the second irradiating unit 12 is incident on the combining unit 30 via the parallel unit 20.

[0023] 1 to 3, the parallel portion 20 has a first parallel portion 21 and a second parallel portion 22. The first parallel portion 21 and the second parallel portion 22 are arranged at 90° angles to each other with the combined portion 30 therebetween.

[0024] The first parallel part 21 has, for example, a first optical element that optically acts on the first electromagnetic wave L1 irradiated from the first irradiating part 11. The first optical element includes a collimation lens that converts the first electromagnetic wave L1 irradiated from the first irradiating part 11 into parallel light and guides it to the combining part 30. The first parallel part 21 is fixed and / or positioned so that the first electromagnetic wave L1 from the first irradiating part 11 enters the first parallel part 21 and exits the first parallel part 21 to the combining part 30.

[0025] The second parallel part 22 has, for example, a second optical element that optically acts on the second electromagnetic wave L2 irradiated from the second irradiating part 12. The second optical element includes a collimation lens that converts the second electromagnetic wave L2 irradiated from the second irradiating part 12 into parallel light and guides it to the combining part 30. The second parallel part 22 is fixed and / or positioned so that the second electromagnetic wave L2 from the second irradiating part 12 enters the second parallel part 22 and exits the second parallel part 22 to the combining part 30.

[0026] The combining unit 30 has a third optical element 31 including, for example, a prism or a cold mirror. The third optical element 31 combines the first electromagnetic wave L1 irradiated from the first irradiating unit 11 and passed through the first parallel portion 21 with the second electromagnetic wave L2 irradiated from the second irradiating unit 12 and passed through the second parallel portion 22, aligning their traveling directions, and guiding them in a predetermined direction. The third optical element 31 may be configured in any way as long as it has a function related to such combining.

[0027] The third optical element 31 outputs the first electromagnetic wave L1 and the second electromagnetic wave L2, which are incident from different directions, in a predetermined direction. The third optical element 31 reflects the first electromagnetic wave L1 irradiated from the first irradiating unit 11 and transmits the second electromagnetic wave L2 irradiated from the second irradiating unit 12. For example, if the first electromagnetic wave L1 is visible light and the second electromagnetic wave L2 is infrared light, the third optical element 31 reflects the visible light and transmits the infrared light. The third optical element 31 combines the first electromagnetic wave L1 irradiated from the first irradiating unit 11 and the second electromagnetic wave L2 irradiated from the second irradiating unit 12 by aligning their optical axes. The third optical element 31 guides the combined electromagnetic waves to the change unit 40. Therefore, the third optical element 31 is fixed and / or positioned so that the first electromagnetic wave L1 from the first irradiating unit 11 is reflected and the second electromagnetic wave L2 from the second irradiating unit 12 is transmitted. The third optical element 31 is fixed and / or positioned so that the combined electromagnetic wave is output to the changing unit 40.

[0028] The combining unit 30 has a third optical element 31 on the incident side of the electromagnetic waves including the first electromagnetic wave L1 and the second electromagnetic wave L2, and a fourth optical element 32 on the output side of the combined electromagnetic wave to the changing unit 40. The fourth optical element 32 is configured integrally with the third optical element 31 located on the incident side. The fourth optical element 32 includes an anamorphic lens or the like that optically acts on the combined electromagnetic wave to change the beam shape of the electromagnetic wave into an elliptical shape.

[0029] The change unit 40 includes, for example, a reflecting mirror that changes (deflects) the irradiation direction of the incident electromagnetic wave. The reflecting mirror includes a MEMS (Micro Electro Mechanical Systems) mirror, a polygon mirror, a galvanometer mirror, and the like. Hereinafter, the description will be made assuming that the reflecting mirror includes a MEMS mirror. The change unit 40 changes the irradiation direction of the incident electromagnetic wave guided by the combining unit 30 and outputs the electromagnetic wave. The change unit 40 changes the irradiation direction of the electromagnetic wave along a first direction D1, which is a direction in which the irradiation direction can be changed, and a second direction D2, which is a direction in which the irradiation direction can be changed and intersects with the first direction D1. The change unit 40 is a two-dimensional MEMS mirror that scans the electromagnetic wave irradiated by the irradiation unit 10 in two dimensions. The change unit 40 has a reflecting surface that oscillates around a first axis corresponding to scanning along the first direction D1 and a second axis intersecting the first axis and corresponding to scanning along the second direction D2. The two-dimensional MEMS mirror of the change unit 40 performs a resonant operation along the first direction D1 and a non-resonant operation along the second direction D2.

[0030] The change unit 40 has a predetermined rotation axis and rotates around the rotation axis. The rotation does not necessarily have to be an orbital motion, and may be, for example, a swinging motion that includes a partial rotation of less than one revolution. By rotating, the change unit 40 changes the irradiation direction of the electromagnetic wave incident from the combiner unit 30 toward the first branching unit 50a. The change unit 40 is positioned so that the electromagnetic wave emitted from the combiner unit 30 is incident on it, and the electromagnetic wave whose irradiation direction has been changed by the change unit 40 is emitted toward the first branching unit 50a.

[0031] The first branching unit 50a has a fifth optical element such as a hot mirror. The fifth optical element branches the electromagnetic wave whose irradiation direction has been changed by the changing unit 40 into a first electromagnetic wave L1 irradiated from the first irradiating unit 11 and a second electromagnetic wave L2 irradiated from the second irradiating unit 12, branches the traveling directions of the waves, and guides them in different directions. The fifth optical element may be configured in any way as long as it has a function related to such branching.

[0032] The fifth optical element emits the first electromagnetic wave L1 and the second electromagnetic wave L2 in different directions. The fifth optical element transmits the first electromagnetic wave L1 irradiated from the first irradiating unit 11 and reflects the second electromagnetic wave L2 irradiated from the second irradiating unit 12. For example, if the first electromagnetic wave L1 is visible light and the second electromagnetic wave L2 is infrared light, the fifth optical element transmits the visible light and reflects the infrared light. The fifth optical element separates the first electromagnetic wave L1 irradiated from the first irradiating unit 11 and the second electromagnetic wave L2 irradiated from the second irradiating unit 12 by separating their optical axes. The fifth optical element guides the separated first electromagnetic wave L1 to the waveguiding unit 60 or the second wave-separating unit 50b. The fifth optical element guides the separated second electromagnetic wave L2 to an object located outside the electromagnetic wave irradiation device 1.

[0033] Therefore, the fifth optical element is fixed and / or positioned so that the first electromagnetic wave L1 from the first irradiating unit 11 passes through and the second electromagnetic wave L2 from the second irradiating unit 12 is reflected. The fifth optical element is fixed and / or positioned so that the demultiplexed first electromagnetic wave L1 is emitted to the waveguide unit 60 or the second demultiplexing unit 50b, and the demultiplexed second electromagnetic wave L2 is emitted to the target object.

[0034] 3, the second branching unit 50b has a sixth optical element located after the first branching unit 50a. The sixth optical element includes a mirror or the like that optically acts on the first electromagnetic wave L1 whose irradiation direction has been changed by the changing unit 40. The sixth optical element may be a prism or a half mirror. The sixth optical element is fixed and / or positioned so that the first electromagnetic wave L1 enters the sixth optical element from the fifth optical element and exits the sixth optical element to the second detection unit 82, which will be described later.

[0035] The second branching unit 50b guides a portion of the first electromagnetic wave L1, the traveling direction of which has been changed to the first direction D1 by the changer 40, to the second detector 82. The second branching unit 50b is disposed at a position where the first electromagnetic wave L1 is incident. The first electromagnetic wave L1 is irradiated at a third time point between a first time point and a second time point, which are different times when the irradiation direction of the first electromagnetic wave L1 changes along the first direction D1. The second branching unit 50b acts on the first electromagnetic wave L1, the irradiation direction of which has been changed by the changer 40, such that a first path P1 of the first electromagnetic wave L1 that has changed in a first range including the first and second time points and a second path P2 of the first electromagnetic wave L1 that has changed in a second range excluding the first range and including the third time point are different from each other. The first path P1 includes, for example, a path along which the first electromagnetic wave L1 is not reflected by the second branching unit 50b, as shown in FIG. 1 . The second path P2 includes, for example, a path along which the first electromagnetic wave L1 is reflected at the second branching section 50b as shown in FIG.

[0036] 1, for convenience of explanation, in addition to the first electromagnetic waves L1 at both ends of the first direction D1 that are irradiated at the first and second points in time, the first electromagnetic wave L1 at the center of the first direction D1 that is irradiated at a third point in time therebetween is also illustrated. However, in reality, the first electromagnetic wave L1 at the center of the first direction D1 is reflected by the second branching unit 50b shown in FIG. 3 and guided to the second detection unit 82, and is not guided to the first detection unit 81 described below.

[0037] 1 and 2 , the waveguide unit 60 includes, for example, a pair of seventh and eighth optical elements 61 and 62 that fold back the first electromagnetic wave L1 that has passed through the first branching unit 50 a. Each of the seventh and eighth optical elements 61 and 62 includes a mirror or the like. The pair of seventh and eighth optical elements 61 and 62 are fixed and / or positioned so that the first electromagnetic wave L1 that has passed through the first branching unit 50 a enters the pair of seventh and eighth optical elements 61 and 62 and exits the pair of seventh and eighth optical elements 61 and 62 to the focusing unit 70.

[0038] The focusing unit 70 includes, for example, a ninth optical element that acts on the first electromagnetic wave L1 to focus the first electromagnetic wave L1 along the second direction D2 on the detection surface of the first detection unit 81. The ninth optical element includes a cylindrical lens or the like. The cylindrical lens is disposed in a path between the changing unit 40 and the first detection unit 81 that is longer than the path length from the changing unit 40 to the second branching unit 50b, as an optical element that minimizes changes in the trajectory of the first electromagnetic wave L1 in the second direction D2 on the detection surface of the first detection unit 81 based on changes in the irradiation direction of the first electromagnetic wave L1 in the second direction D2. The focusing unit 70 has positive power along the second direction D2. Here, the trajectory of the first electromagnetic wave L1 on the detection surface of the first detection unit 81 refers to changes in the spot position of the first electromagnetic wave L1 on the detection surface of the first detection unit 81.

[0039] The focusing unit 70 is disposed on the first path P1 between the second branching unit 50b and the first detection unit 81. The focusing unit 70 is disposed so that the change unit 40 and the first detection unit 81 are optically conjugate with each other in the second direction D2. In this case, the second branching unit 50b is disposed in the path between the change unit 40 and the cylindrical lens, which is an optical element included in the focusing unit 70.

[0040] 1 to 3, the detection unit 80 includes a first detection unit 81 and a second detection unit 82. The first detection unit 81 and the second detection unit 82 are located on a first path P1 and a second path P2, respectively, of the paths along which the first electromagnetic wave L1 propagates.

[0041] The first detection unit 81 includes, for example, a photodiode (PD), which is a semiconductor diode that functions as a photodetector. The first detection unit 81 includes multiple detectors arranged at positions where a first electromagnetic wave L1, whose irradiation direction changes in a first direction D1, is incident at a first time point and a second time point, which are different from each other. The multiple detectors include, for example, a first detector 81a and a second detector 81b. The first detector 81a is arranged at a position where the first electromagnetic wave L1, whose irradiation direction changes in the first direction D1, is incident at the first time point. The second detector 81b is arranged at a position where the first electromagnetic wave L1, whose irradiation direction changes in the first direction D1, is incident at the second time point.

[0042] The first detection unit 81 detects the first electromagnetic wave L1 for monitoring in order to detect the irradiation direction of the first electromagnetic wave L1 changed by the changing unit 40, i.e., the deflection angle of the reflecting surface in the changing unit 40. The first detection unit 81 detects, for example, the first electromagnetic wave L1 having a wavelength in the visible range on the first path P1. The first detection unit 81 detects the first electromagnetic wave L1 when the irradiation direction is changed by the changing unit 40 along the first path P1. Therefore, the first detection unit 81 is fixed and / or positioned so that the first electromagnetic wave L1 that has propagated along the first path P1 without being reflected by the second branching unit 50b, among the first electromagnetic waves L1 whose irradiation direction has been changed by the changing unit 40, is incident on the first detection unit 81.

[0043] The second detection unit 82 has, for example, a photodiode (PD), which is a semiconductor diode that functions as a photodetector. The second detection unit 82 is disposed at a position where at least a portion of the first electromagnetic wave L1 whose irradiation direction changes in the first direction D1 and at least a portion of the first electromagnetic wave L1 whose irradiation direction changes in the second direction D2 are incident. The second detection unit 82 includes a third detector 82 disposed at a position where the first electromagnetic wave L1 whose irradiation direction changes in the first direction D1 is incident at a third time point that is between the first time point and the second time point.

[0044] The second detection unit 82 detects the first electromagnetic wave L1 for monitoring in order to detect the irradiation direction of the first electromagnetic wave L1 changed by the changing unit 40, i.e., the deflection angle of the reflecting surface of the changing unit 40. The second detection unit 82 detects, for example, the first electromagnetic wave L1 having a wavelength in the visible range on the second path P2. The second detection unit 82 detects the first electromagnetic wave L1 when the irradiation direction is changed by the changing unit 40 along the second path P2. Therefore, the second detection unit 82 is fixed and / or positioned so that the first electromagnetic wave L1 that has been reflected by the second branching unit 50b and propagated along the second path P2, of the first electromagnetic wave L1 whose irradiation direction has been changed by the changing unit 40, is incident on the second detection unit 82.

[0045] The control unit 90 includes a processor, a programmable circuit, a dedicated circuit, or any combination thereof. The processor includes a general-purpose processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), or a dedicated processor specialized for specific processing. The programmable circuit includes an FPGA (Field-Programmable Gate Array), etc. The dedicated circuit includes an ASIC (Application Specific Integrated Circuit), etc. The control unit 90 is communicably connected to each component that makes up the electromagnetic wave irradiation device 1, and executes processing related to the operation of the electromagnetic wave irradiation device 1 while controlling each component.

[0046] As described above, in the electromagnetic wave irradiation device 1, the second electromagnetic wave L2 as infrared rays irradiated from the second irradiation unit 12 has its irradiation direction changed by the changing unit 40, is reflected by the first branching unit 50a, and is emitted from the electromagnetic wave irradiation device 1. The second electromagnetic wave L2 scans objects and the like present around the electromagnetic wave irradiation device 1.

[0047] Additionally, in the electromagnetic wave irradiation device 1, the irradiation direction of the first electromagnetic wave L1 as visible light irradiated from the first irradiating unit 11 is changed by the changing unit 40 together with the second electromagnetic wave L2 irradiated from the second irradiating unit 12. After the irradiation direction of the first electromagnetic wave L1 is changed by the changing unit 40, it passes through the first branching unit 50a. The first electromagnetic wave L1 that has passed through the first branching unit 50a is detected by the first detecting unit 81 or the second detecting unit 82 depending on the deflection direction caused by the rotating changing unit 40.

[0048] The control unit 90 of the electromagnetic wave irradiation device 1 detects the orientation of the reflective surface of the changing unit 40 based on the detection of the first electromagnetic wave L1 by the first detection unit 81 and the second detection unit 82. The control unit 90 detects the rotation angle, i.e., the deflection angle, for each of the first axis and the second axis of the changing unit 40. The control unit 90 detects the irradiation direction of the second electromagnetic wave L2 irradiated to the outside of the electromagnetic wave irradiation device 1 by monitoring the deflection angle based on the first electromagnetic wave L1.

[0049] The control unit 90 calculates the rotation angle about the first axis corresponding to scanning along the first direction D1 based on the first detection signal of the first electromagnetic wave L1 by the first detection unit 81. The control unit 90 calculates the rotation angle about the first axis, for example, by referring to a first angle detection table stored in the electromagnetic wave irradiation device 1. The first angle detection table associates the rotation angle of the reflecting mirror about the first axis when the first detector 81 a or the second detector 81 b detects the first electromagnetic wave L1 reflected by the reflecting mirror of the rotationally moving modification unit 40, with the rotation angle of the reflecting mirror relative to the elapsed time from that state.

[0050] The control unit 90, for example, approximates the change over time in the rotation angle of the reflecting mirror about the first axis using a sine wave function. The control unit 90 determines multiple points in time on the sine wave function, such as the first and second points in time, based on the first detection signals obtained from the first detector 81 a and the second detector 81 b. The control unit 90 calculates the current rotation angle about the first axis by interpolating between the first and second points in time using the sine wave function.

[0051] The control unit 90 calculates the rotation angle about the second axis corresponding to scanning along the second direction D2 based on the second detection signal of the first electromagnetic wave L1 by the second detection unit 82. The control unit 90 calculates the rotation angle about the second axis, for example, by referring to a second angle detection table stored in the electromagnetic wave irradiation device 1. The second angle detection table associates the rotation angle about the second axis of the reflecting mirror of the rotationally moving modification unit 40 when the first electromagnetic wave L1 reflected by the reflecting mirror is detected by the third detector 82 with the rotation angle of the reflecting mirror relative to the elapsed time from that state.

[0052] For example, the control unit 90 approximates the change over time in the rotation angle of the reflecting mirror about the second axis using a sine wave function. The control unit 90 determines multiple points in time on the sine wave function based on the second detection signal obtained from the third detector 82. The control unit 90 calculates the current rotation angle about the second axis by interpolating between the multiple points in time using the sine wave function.

[0053] In this way, the control unit 90 of the electromagnetic wave irradiation device 1 detects the rotation angle of the reflecting mirror of the changing unit 40 with respect to both the first axis and the second axis, based on the elapsed time from the light receiving timing of each of the first detection unit 81 and the second detection unit 82. In this way, the control unit 90 of the electromagnetic wave irradiation device 1 detects the irradiation direction of the second electromagnetic wave L2 irradiated toward the target located outside the electromagnetic wave irradiation device 1.

[0054] Fig. 4 is a schematic diagram of the first detection unit 81 in Fig. 1 viewed in the traveling direction of the first electromagnetic wave L1. Referring to Fig. 4, the configuration and functions of the electromagnetic wave irradiation device 1 related to the calculation process of the rotation angle of the reflecting mirror about the first axis by the control unit 90 will be mainly described. Here, the first direction D1 in Fig. 4 indicates the direction on the detection surface of the first detection unit 81 that corresponds to the first direction D1 in which the change unit 40 changes the irradiation direction of the first electromagnetic wave L1. The second direction D2 in Fig. 4 indicates the direction on the detection surface of the first detection unit 81 that corresponds to the second direction D2 in which the change unit 40 changes the traveling direction of the first electromagnetic wave L1.

[0055] Each of the first detector 81a and the second detector 81b of the first detection unit 81 includes a linear detector arranged perpendicular to the first direction D1. The multiple detectors including the first detector 81a and the second detector 81b are arranged so that the first electromagnetic wave L1 is incident on the center of the detection surface of the detector. The first detection unit 81 detects the first electromagnetic wave L1 scanned in a first scanning range R1 along the first direction D1. A second scanning range R2 of the first electromagnetic wave L1 along the second direction D2 in the first detection unit 81 is sufficiently narrower than the first scanning range R1 along the first direction D1 in the first detection unit 81.

[0056] In the first detection unit 81, the second scanning range R2 is sufficiently narrower than the first scanning range R1 because the two-dimensional MEMS mirror of the changing unit 40 performs a non-resonant operation along the second direction D2 and the cylindrical lens of the immediately preceding focusing unit 70 has a positive power along the second direction D2. On the other hand, in the first detection unit 81, the first scanning range R1 is wider than the second scanning range R2 because the two-dimensional MEMS mirror of the changing unit 40 performs a resonant operation along the first direction D1.

[0057] The first electromagnetic wave L1 exhibits an elliptical spot shape at the first detection unit 81 due to the optical action of the anamorphic lens of the fourth optical element 32 of the combining unit 30 and the cylindrical lens of the focusing unit 70. The beam width of the first electromagnetic wave L1 at the first detection unit 81 is wide in the second direction D2 and narrow in the first direction D1. The first electromagnetic wave L1 at the first detection unit 81 is defocused in the second direction D2.

[0058] The first detector 81a detects the entire beam of the first electromagnetic wave L1, which is elongated vertically along the second direction D2 as shown in FIG. 4 , at a first point in time, and outputs a first detection signal to the control unit 90. The first detector 81a is positioned so that the first electromagnetic wave L1 is incident on the detection surface of the first detector 81a within a predetermined range including the center of the detection surface of the first detector 81a, i.e., the center of the second direction D2. Because the second scanning range R2 of the first electromagnetic wave L1 is narrow, even if the first detector 81a is not completely perpendicular to the first direction D1 and is slightly tilted from the second direction D2, the relative deviation of the first point in time between scans of the first electromagnetic wave L1 along the second direction D2 is reduced. Because the second scanning range R2 of the first electromagnetic wave L1 is narrow, the influence of the tilt of the first detector 81a is reduced, and the first point in time is determined at approximately the same phase point in the sinusoidal function between scans of the first electromagnetic wave L1 along the second direction D2.

[0059] The second detector 81b detects the entire beam of the first electromagnetic wave L1, which is elongated vertically along the second direction D2 as shown in FIG. 4 , at a second point in time, and outputs a first detection signal to the control unit 90. The second detector 81b is positioned so that the first electromagnetic wave L1 is incident on the detection surface of the second detector 81b within a predetermined range including the center of the detection surface of the second detector 81b, i.e., the center of the second direction D2. Because the second scanning range R2 of the first electromagnetic wave L1 is narrow, even if the second detector 81b is not completely perpendicular to the first direction D1 and is slightly tilted from the second direction D2, the relative deviation of the second point in time between scans of the first electromagnetic wave L1 along the second direction D2 is reduced. Because the second scanning range R2 of the first electromagnetic wave L1 is narrow, the influence of the tilt of the second detector 81b is reduced, and the second point in time between scans of the first electromagnetic wave L1 along the second direction D2 is determined at approximately the same phase point in the sinusoidal function.

[0060] The control unit 90 determines a first point in time on the sine wave function at the timing when the first detection signal is detected from the first detector 81a. The control unit 90 determines a second point in time on the sine wave function at the timing when the first detection signal is detected from the second detector 81b. For example, the control unit 90 determines one of phase points slightly shifted from the peak or valley of the sine wave function as the first point in time, and determines the other as the second point in time. The control unit 90 calculates and acquires the current rotation angle of the reflecting mirror around the first axis by interpolating between the first and second points in time with the sine wave function.

[0061] Fig. 5 is a schematic diagram of the second detection unit 82 in Fig. 3 viewed in the traveling direction of the first electromagnetic wave L1. Referring to Fig. 5, the configuration and functions of the electromagnetic wave irradiation device 1 related to the process of calculating the rotation angle of the reflecting mirror about the second axis by the control unit 90 will be mainly described. Here, the first direction D1 in Fig. 5 indicates the direction on the detection surface of the second detection unit 82 that corresponds to the first direction D1 in which the change unit 40 changes the traveling direction of the first electromagnetic wave L1. The second direction D2 in Fig. 5 indicates the direction on the detection surface of the second detection unit 82 that corresponds to the second direction D2 in which the change unit 40 changes the traveling direction of the first electromagnetic wave L1.

[0062] The third detector 82 of the second detection unit 82 includes a linear detector disposed at an angle with respect to the first direction D1. The second detection unit 82 is disposed at an angle with respect to the trajectory of the first electromagnetic wave L1 on the detection surface of the second detection unit 82, which is determined based on a change in the irradiation direction of the first electromagnetic wave L1 in the first direction D1. Here, the trajectory of the first electromagnetic wave L1 on the detection surface of the second detection unit 82 refers to a change in the position of the spot of the first electromagnetic wave L1 on the detection surface of the second detection unit 82. The inclination of the third detector 82 may be set so that the second scanning range R2 of the first electromagnetic wave L1 is included in the range of the third detector 82 that can detect the incidence of the first electromagnetic wave L1. The inclination of the third detector 82 may be set according to the resolution with which the third detector 82 detects the first electromagnetic wave L1.

[0063] The second detector 82 detects the first electromagnetic wave L1 scanned in a second scanning range R2 along the second direction D2. The second scanning range R2 of the first electromagnetic wave L1 along the second direction D2 in the second detector 82 is narrower than the first scanning range R1 along the first direction D1 in the second detector 82. The second scanning range R2 in the second detector 82 is wider than the second scanning range R2 in the first detector 81 shown in FIG. 4 .

[0064] In the second detection unit 82, the second scanning range R2 is narrower than the first scanning range R1 based on the non-resonant operation of the two-dimensional MEMS mirror of the change unit 40 along the second direction D2. On the other hand, in the second detection unit 82, the first scanning range R1 is wider than the second scanning range R2 based on the resonant operation of the two-dimensional MEMS mirror of the change unit 40 along the first direction D1.

[0065] The first electromagnetic wave L1 exhibits an elliptical spot shape at the second detector 82 due to the optical action of the anamorphic lens of the fourth optical element 32 of the combining unit 30. The anamorphic lens of the fourth optical element 32 functions as an optical element that makes the spot shape of the first electromagnetic wave L1 on the detection surface of the second detector 82 an ellipse whose major axis corresponds to the direction of movement of the trajectory of the first electromagnetic wave L1 based on the change in the irradiation direction in the first direction D1. The beam width of the first electromagnetic wave L1 at the second detector 82 is narrow in the second direction D2 and wide in the first direction D1. The first electromagnetic wave L1 at the second detector 82 forms a substantial image in the second direction D2. The beam width of the first electromagnetic wave L1 at the second detector 82 in the second direction D2 is narrower than the beam width of the first electromagnetic wave L1 at the first detector 81 in the second direction D2, as shown in FIG. 4 .

[0066] 5, the third detector 82 detects the beam of the first electromagnetic wave L1 that is elongated horizontally along the first direction D1 at a third point in time, and outputs a second detection signal to the control unit 90. At this time, because the third detector 82 is disposed at an angle with respect to the first direction D1, the third point in time at which the first electromagnetic wave L1 is detected by the third detector 82 is different at both ends of the second scanning range R2 in the second direction D2.

[0067] For example, a first time difference occurs between a first time point when the first electromagnetic wave L1 is detected by the first detector 81a shown in Fig. 4 and a third time point when the first electromagnetic wave L1 is detected by the third detector 82 at the upper end of the second scanning range R2 shown in Fig. 5. Similarly, a second time difference occurs between the first time point when the first electromagnetic wave L1 is detected by the first detector 81a shown in Fig. 4 and a third time point when the first electromagnetic wave L1 is detected by the third detector 82 at the lower end of the second scanning range R2 shown in Fig. 5. Because the third detector 82 is disposed at an angle with respect to the first direction D1, the first time difference becomes shorter than the second time difference.

[0068] The control unit 90 determines the third point in time on the sine wave function at the timing at which the second detection signal is detected in accordance with a change in the time difference between the first point in time at which the first electromagnetic wave L1 is detected by the first detector 81 a and the third point in time at which the first electromagnetic wave L1 is detected by the third detector 82. The control unit 90 determines the third point in time on the sine wave function at the timing at which the second detection signal is detected from the third detector 82. The control unit 90 interpolates between the plurality of third points in time with the sine wave function to calculate and obtain the current rotation angle of the reflecting mirror around the second axis.

[0069] The electromagnetic wave irradiation device 1 according to the first embodiment described above can accurately detect the irradiation direction of the irradiated electromagnetic waves. The electromagnetic wave irradiation device 1 includes a changer 40, a second branching unit 50b, a first detector 81, and a second detector 82. This allows the electromagnetic wave irradiation device 1 to separate a portion of the first electromagnetic wave L1, the irradiation direction of which has been changed by the changer 40, from the other portion using the second branching unit 50b, and detect these portions using the first detector 81 and the second detector 82, respectively. Therefore, the electromagnetic wave irradiation device 1 can calculate the rotation angles of the reflecting mirror in different directions using the first detector 81 and the second detector 82. The electromagnetic wave irradiation device 1 can accurately detect the rotation angles of the reflecting mirror in two directions, even for a changer 40 having a two-dimensional MEMS mirror, for example.

[0070] This allows the electromagnetic wave irradiation device 1 to accurately detect the irradiation direction of the second electromagnetic wave L2 emitted from the first branching unit 50a toward an object located outside the electromagnetic wave irradiation device 1. Therefore, the electromagnetic wave irradiation device 1 can improve the detection accuracy when the information acquisition system detects an object located in any direction relative to the electromagnetic wave irradiation device 1. The electromagnetic wave irradiation device 1 improves the convenience of the information acquisition system that functions as a distance measurement system.

[0071] The first detection unit 81 includes a plurality of detectors arranged at positions where the first electromagnetic wave L1, whose irradiation direction changes in the first direction D1, is incident at a first time point and a second time point, which are different from each other. This allows the electromagnetic wave irradiation device 1 to increase the number of detection points of the first electromagnetic wave L1, whose irradiation direction changes in the first direction D1. Therefore, the electromagnetic wave irradiation device 1 can more accurately execute the sinusoidal function interpolation process using the control unit 90. By interpolating the period between the first time point and the second time point with a sinusoidal function, the electromagnetic wave irradiation device 1 can more accurately calculate the current rotation angle of the reflecting mirror around the first axis.

[0072] The second branching unit 50b is disposed at a position where the first electromagnetic wave L1 irradiated at a timing between the first time point and the second time point is incident. This allows the electromagnetic wave irradiation device 1 to selectively guide to the second detection unit 82 only the first electromagnetic wave L1 located in the center of the first direction D1, out of the first electromagnetic wave L1 whose irradiation direction is changed in the first direction D1 by the change unit 40.

[0073] The second detection unit 82 is disposed at an angle relative to the trajectory of the first electromagnetic wave L1 on the detection surface of the second detection unit 82, based on a change in the irradiation direction in the first direction D1. This allows the electromagnetic wave irradiation device 1 to more accurately calculate the current rotation angle of the reflecting mirror around the second axis, as described above, based on the time difference between the first point in time when the first electromagnetic wave L1 is detected by the first detector 81a and the third point in time when the first electromagnetic wave L1 is detected by the third detector 82.

[0074] The focusing unit 70 functions as an optical element that reduces the change in the trajectory of the first electromagnetic wave L1 on the detection surface of the first detection unit 81 based on the change in the first electromagnetic wave L1 whose irradiation direction changes in the second direction D2.

[0075] As a result, even if the first detector 81a is not completely perpendicular to the first direction D1 and is slightly tilted from the second direction D2, the electromagnetic wave irradiation device 1 can reduce the relative shift of the first time point during the scanning of the first electromagnetic wave L1 along the second direction D2. Therefore, the electromagnetic wave irradiation device 1 can reduce the influence of the tilt of the first detector 81a and accurately determine the first time point as approximately the same phase point in the sine wave function during the scanning of the first electromagnetic wave L1 along the second direction D2.

[0076] Similarly, even if the second detector 81b is not completely perpendicular to the first direction D1 but is slightly tilted from the second direction D2, the electromagnetic wave irradiation device 1 can reduce the relative deviation of the second time point during the scanning of the first electromagnetic wave L1 along the second direction D2. Therefore, the electromagnetic wave irradiation device 1 can reduce the influence of the tilt of the second detector 81b and accurately determine the second time point as approximately the same phase point in the sine wave function during the scanning of the first electromagnetic wave L1 along the second direction D2.

[0077] The changing unit 40 has a reflecting surface that swings around a first axis and a second axis that intersects with the first axis, thereby allowing the electromagnetic wave irradiation device 1 to change the irradiation direction of the second electromagnetic wave L2 emitted to the outside of the electromagnetic wave irradiation device 1 in two dimensions.

[0078] The electromagnetic wave irradiation device 1 further includes a control unit 90 that detects the orientation of the reflecting surface of the reflecting mirror based on the detection of the first electromagnetic wave L1 by the first detection unit 81 and the second detection unit 82. This enables the electromagnetic wave irradiation device 1 to accurately perform the calculation process of the rotation angle of the reflecting mirror based on the above-mentioned complementation process by itself.

[0079] The anamorphic lens of the fourth optical element 32 functions as an optical element that shapes the spot shape of the first electromagnetic wave L1 on the detection surface of the second detection unit 82 into an ellipse whose major axis corresponds to the direction of movement of the trajectory of the first electromagnetic wave L1 based on changes in the irradiation direction of the first electromagnetic wave L1 in the first direction D1. This allows the electromagnetic wave irradiation device 1 to narrow the width of the first electromagnetic wave L1 along the second direction D2. Therefore, the electromagnetic wave irradiation device 1 can detect most of the first electromagnetic wave L1 using the linear third detector 82, which is arranged at an angle with respect to the first direction D1. The electromagnetic wave irradiation device 1 can more accurately calculate the current rotation angle of the reflecting mirror around the second axis.

[0080] In the first embodiment, the second branching unit 50b reflects the first electromagnetic wave L1 at the third time point among the first electromagnetic waves L1 whose irradiation direction has been changed to the first direction D1 by the change unit 40, and guides the reflected first electromagnetic waves L1 to the second detection unit 82. However, the present invention is not limited to this. The second branching unit 50b may reflect the first electromagnetic waves L1 at the first and second time points among the first electromagnetic waves L1 whose irradiation direction has been changed to the first direction D1 by the change unit 40, and guide the reflected first electromagnetic waves L1 to the first detection unit 81.

[0081] In the first embodiment, the first detection unit 81 includes multiple detectors arranged at positions where the first electromagnetic wave L1, whose irradiation direction changes in the first direction D1, is incident at a first time point and a second time point, which are different from each other. However, this is not limited to this. The first detection unit 81 may include only one detector. In this case, the control unit 90 may determine one time point on the sine wave function as the first time point based on the first detection signal obtained from the first detection unit 81. The control unit 90 may calculate the current rotation angle around the first axis by interpolating the sine wave function for other times from the first time point.

[0082] In the first embodiment, the second detector 82 is described as being disposed at an angle with respect to the trajectory of the first electromagnetic wave L1 on the detection surface of the second detector 82 based on a change in the irradiation direction in the first direction D1. However, this is not limiting. The second detector 82 does not have to be disposed at an angle with respect to the trajectory. The second detector 82 may also be disposed so as to be perpendicular to the trajectory.

[0083] In the first embodiment, the control unit 90 determines multiple points in time on the sine wave function based on the second detection signal obtained from the third detector 82. However, this is not limiting. The control unit 90 may determine one point in time on the sine wave function as the third point in time based on the second detection signal obtained from the second detector 82. The control unit 90 may calculate the current rotation angle around the second axis by interpolating the sine wave function from the third point in time to other times.

[0084] In the first embodiment, the cylindrical lens of the focusing unit 70 is described as functioning as an optical element that reduces the change in the trajectory of the first electromagnetic wave L1 on the detection surface of the first detecting unit 81, which is based on the change in the first electromagnetic wave L1 whose irradiation direction changes in the second direction D2. However, the present invention is not limited to this. Instead of or in addition to such a cylindrical lens, the electromagnetic wave irradiation device 1 may include any other optical element having a similar function, or may not include such an optical element at all.

[0085] In the first embodiment, the two-dimensional MEMS mirror of the change unit 40 resonates along the first direction D1, and therefore the speed at which the irradiation direction of the first electromagnetic wave L1 changes in the first direction D1 differs between, for example, the first time point and the third time point. Therefore, the speed at which the spot of the first electromagnetic wave L1 moves in the first direction D1 on the detection surface of the first detection unit 81 is not constant. Therefore, the focusing unit 70 may include an optical member having a curvature that can make the speed at which the spot of the first electromagnetic wave L1 moves in the first direction D1 on the detection surface of the first detection unit 81 constant.

[0086] In the first embodiment, the electromagnetic wave irradiation device 1 is described as further including a control unit 90 that detects the orientation of the reflective surface of the reflective mirror based on the detection of the first electromagnetic wave L1 by the first detection unit 81 and the second detection unit 82, but is not limited to this. The electromagnetic wave irradiation device 1 does not need to include such a control unit 90. The various processes described above that were executed by the control unit 90 may be executed by any external device other than the electromagnetic wave irradiation device 1. In this case, the electromagnetic wave irradiation device 1 may output the first detection signal and the second detection signal from the first detection unit 81 and the second detection unit 82, respectively, to the external device.

[0087] In the first embodiment, the anamorphic lens of the fourth optical element 32 is described as functioning as an optical element that changes the spot shape of the first electromagnetic wave L1 on the detection surface of the second detection unit 82 into an ellipse whose major axis corresponds to the direction of movement of the trajectory based on a change in the irradiation direction of the first electromagnetic wave L1 in the first direction D1. However, this is not limited to this. The electromagnetic wave irradiation device 1 does not need to change the spot shape of the first electromagnetic wave L1 on the detection surface of the second detection unit 82 to an ellipse. In this case, the electromagnetic wave irradiation device 1 does not need to have an anamorphic lens of the fourth optical element 32.

[0088] In the first embodiment, the anamorphic lens of the fourth optical element 32 and the cylindrical lens of the focusing unit 70 function as optical elements that make the spot shape of the first electromagnetic wave L1 on the detection surface of the first detection unit 81 an ellipse whose minor axis corresponds to the direction of movement of the trajectory of the first electromagnetic wave L1 based on a change in the irradiation direction in the first direction D1. However, this is not limited to this. The electromagnetic wave irradiation device 1 does not need to make the spot shape of the first electromagnetic wave L1 on the detection surface of the first detection unit 81 an ellipse. In this case, the electromagnetic wave irradiation device 1 does not need to have the anamorphic lens of the fourth optical element 32 and the cylindrical lens of the focusing unit 70.

[0089] In the first embodiment, the first electromagnetic wave L1 and the second electromagnetic wave L2 are irradiated at the same time in the electromagnetic wave irradiation device 1, but the present invention is not limited to this. The first electromagnetic wave L1 and the second electromagnetic wave L2 may be irradiated at different times.

[0090] In the first embodiment, the first irradiating unit 11 is described as irradiating the first electromagnetic wave L1 as visible light, but the present invention is not limited thereto. The first irradiating unit 11 may irradiate the first electromagnetic wave L1 having any wavelength other than visible light. In the first embodiment, the first irradiating unit 11 is described as irradiating the first electromagnetic wave L1 as a continuous wave, but the present invention is not limited thereto. The first irradiating unit 11 may irradiate the first electromagnetic wave L1 in a pulsed form.

[0091] In the first embodiment, the control unit 90 of the electromagnetic wave irradiation device 1 executes the interpolation process based on a sine wave function, but the present invention is not limited to this. The control unit 90 may execute the interpolation process based on any other function.

[0092] 6 is a perspective view showing a schematic configuration of an electromagnetic wave irradiation device 1 according to a second embodiment of the present disclosure. An example of the configuration and functions of the electromagnetic wave irradiation device 1 according to the second embodiment will be mainly described with reference to FIG.

[0093] The electromagnetic wave irradiation device 1 according to the second embodiment differs from the first embodiment in that it does not have a second branching unit 50b, and all of the first electromagnetic waves L1, the irradiation direction of which has been changed to the first direction D1 by the changing unit 40, are propagated along the same path. Other configurations, functions, effects, and modifications are the same as those of the first embodiment, and the corresponding explanations also apply to the electromagnetic wave irradiation device 1 according to the second embodiment. In the following, components similar to those of the first embodiment are given the same reference numerals, and their explanations will be omitted. Differences from the first embodiment will mainly be explained.

[0094] In the electromagnetic wave irradiation device 1 according to the second embodiment, the first detection unit 81 and the second detection unit 82 are disposed in at least a part of the path of the first electromagnetic wave L1, the irradiation direction of which is changed by the changing unit 40. The first detection unit 81 and the second detection unit 82 are disposed at different positions in the propagation direction of the first electromagnetic wave L1, on the same path along which the first electromagnetic wave L1 scanned by the changing unit 40 is guided. The first detection unit 81 and the second detection unit 82 are both disposed after the cylindrical lens of the focusing unit 70.

[0095] The second detection unit 82 is disposed at a position where a change in the trajectory of the first electromagnetic wave L1 in a plane including the detection surface of the second detection unit 82, based on a change in the first electromagnetic wave L1 in the second direction D2, is larger than a change in the trajectory of the first electromagnetic wave L1 in a plane including the detection surface of the first detection unit 81. For example, the second detection unit 82 is disposed at a position longer than the path length from the cylindrical lens of the focusing unit 70 to the first detection unit 81. The second detection unit 82 is disposed at a position away from the first detection unit 81 on the opposite side to the focusing unit 70.

[0096] In the first detector 81a and the second detector 81b, the first electromagnetic wave L1 is focused in the second direction D2 by the cylindrical lens. On the other hand, in the third detector 82, the first electromagnetic wave L1 is not focused in the second direction D2 by the cylindrical lens, but is defocused in the second direction D2. The focusing unit 70 is disposed so that the changing unit 40 and the second detecting unit 82 are not optically conjugate in the second direction D2.

[0097] The first electromagnetic wave L1, whose irradiation direction is changed to the first direction D1 at a first time point and a second time point that are different from each other, is detected by the first detector 81a and the second detector 81b, respectively, via the cylindrical lenses of the focusing unit 70. Similarly, the first electromagnetic wave L1, whose irradiation direction is changed to the first direction D1 at a third time point that is between the first and second time points, is detected by the third detector 82 via the cylindrical lens of the focusing unit 70.

[0098] In the electromagnetic wave irradiation device 1 according to the second embodiment as described above, the second detection unit 82 is also disposed at a position where a part of the first electromagnetic wave L1 whose irradiation direction changes in the first direction D1 and a part of the first electromagnetic wave L1 whose irradiation direction changes in the second direction D2 are incident. As shown in Fig. 5 , the second detection unit 82 is disposed at an angle with respect to the trajectory of the first electromagnetic wave L1 on the detection surface of the second detection unit 82, which is based on the change in the irradiation direction in the first direction D1.

[0099] The electromagnetic wave irradiation device 1 according to the second embodiment does not include the second branching unit 50b as in the first embodiment. The first detection unit 81 and the second detection unit 82 are disposed at positions where the first electromagnetic wave L1 emitted from the cylindrical lens of the focusing unit 70 is incident. The path length from the cylindrical lens of the focusing unit 70 to the second detection unit 82 is longer than the path length from the cylindrical lens of the focusing unit 70 to the first detection unit 81. The second detection unit 82 is disposed at a position away from the first detection unit 81 on the opposite side of the focusing unit 70. This allows the electromagnetic wave irradiation device 1 to have a simpler configuration for the propagation system of the first electromagnetic wave L1. Therefore, the electromagnetic wave irradiation device 1 can be made even more compact than the first embodiment.

[0100] In the second embodiment, the path length from the cylindrical lens of the focusing unit 70 to the second detection unit 82 is described as being longer than the path length from the cylindrical lens of the focusing unit 70 to the first detection unit 81, but this is not limiting. The path length from the cylindrical lens of the focusing unit 70 to the second detection unit 82 may be shorter than the path length from the cylindrical lens of the focusing unit 70 to the first detection unit 81. The second detection unit 82 may be disposed at a position closer to the focusing unit 70 than the first detection unit 81.

[0101] It will be apparent to those skilled in the art that the present disclosure may be embodied in other specific forms other than the above-described embodiments without departing from the spirit or essential characteristics thereof. Therefore, the foregoing description is illustrative and not limiting. The scope of the disclosure is defined not by the foregoing description but by the appended claims. All modifications within the range of equivalents of any modifications are intended to be embraced therein.

[0102] For example, the shape, pattern, size, arrangement, orientation, type, and number of each of the above-mentioned components are not limited to those shown in the above description and drawings. The shape, pattern, size, arrangement, orientation, type, and number of each component may be configured arbitrarily as long as the function can be realized. Each component of the illustrated electromagnetic wave irradiation device 1 is a functional concept, and the specific form of each component is not limited to that shown in the drawings.

[0103] For example, functions included in each configuration can be rearranged so as not to cause logical contradictions, and multiple configurations can be combined into one or divided. Other modifications are possible within the scope of the present disclosure.

[0104] In the above embodiment, the information acquisition system includes a ranging system, but is not limited to this. For example, the present disclosure may be employed in systems other than ranging systems, such as a projector that projects an image by irradiating a two-dimensional MEMS mirror with three-color RGB lasers. For example, the present disclosure may be employed in a system used to inspect two-dimensional MEMS. In these systems, detecting the deflection angle of the two-dimensional MEMS mirror is also useful for improving the performance of the system and the yield of the two-dimensional MEMS mirror.

[0105] REFERENCE SIGNS LIST 1 Electromagnetic wave irradiation device 10 Irradiation unit 11 First irradiation unit (irradiation unit) 12 Second irradiation unit 20 Parallel unit 21 First parallel unit 22 Second parallel unit 30 Combining unit 31 Third optical element 32 Fourth optical element 40 Changing unit 50a First branching unit 50b Second branching unit (branching unit) 60 Waveguide unit 61 Seventh optical element 62 Eighth optical element 70 Focusing unit (optical member) 80 Detecting unit 81 First detection unit 81a First detector 81b Second detector 82 Second detection unit (third detector) 90 Control unit D1 First direction D2 Second direction L1 First electromagnetic wave (electromagnetic wave) L2 Second electromagnetic wave P1 First path P2 Second path R1 First scanning range R2 Second scanning range

Claims

1. An electromagnetic wave irradiation device comprising: an irradiation unit that irradiates electromagnetic waves; a second detection unit that detects the electromagnetic waves; a change unit that changes the irradiation direction of the electromagnetic waves irradiated by the irradiation unit along a first direction and a second direction intersecting the first direction; and a branching unit that guides a portion of the electromagnetic waves whose irradiation direction has been changed by the change unit to the second detection unit.

2. The electromagnetic wave irradiation device of claim 1, further comprising a first detection unit that detects the electromagnetic waves, the first detection unit including a plurality of detectors arranged at a position where the electromagnetic waves, whose irradiation direction changes in the first direction, are incident at a first time point and a second time point that are different from each other, and the branching unit is arranged at a position where the electromagnetic waves irradiated at a timing between the first time point and the second time point are incident.

3. The electromagnetic wave irradiation device according to claim 2, wherein the plurality of detectors are arranged so that the electromagnetic wave is incident on the center of the detection surface of the detector.

4. The electromagnetic wave irradiation device described in claim 2, wherein the second detection unit is arranged at a position where at least a portion of the electromagnetic wave whose irradiation direction changes in the first direction and at least a portion of the electromagnetic wave whose irradiation direction changes in the second direction are incident, and is arranged at an angle with respect to the trajectory of the electromagnetic wave on the detection surface of the second detection unit based on the change in irradiation direction in the first direction.

5. An electromagnetic wave irradiation device as described in claim 2, wherein an optical component is arranged in the path between the change unit and the first detection unit to reduce a change in the trajectory of the electromagnetic wave in the second direction on the detection surface of the first detection unit based on a change in the irradiation direction of the electromagnetic wave in the second direction.

6. The electromagnetic wave irradiation device according to claim 5, wherein the branching section is disposed in a path between the change section and the optical member.

7. The electromagnetic wave irradiation device of claim 2, wherein the modification unit has a reflective surface that oscillates around a first axis and a second axis intersecting the first axis, and further comprises a control unit that detects the orientation of the reflective surface based on the detection of the electromagnetic waves by the first detection unit and the second detection unit.

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