Optical device

Abstract

To provide an optical device that is compact but can secure a scanning angle range of a first deflector.SOLUTION: An optical device includes a first optical system for guiding illumination light from a light source, a first deflector for deflecting the illumination light from the first optical system, a second optical system for guiding the illumination light deflected by the first deflector, and a second deflector for deflecting the illumination light from the second optical system. The first deflector is rotated with a first rotation axis as a center. The second deflector is rotated with a second rotation axis as a center. Refractive power of the second optical system differs between a first section vertical to the first rotation axis and a second section parallel with the first rotation axis. The illumination light from the first optical system is convergent light on the second section.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an optical device for directing an illumination light beam from a light source to an object. [Background technology]

[0002] Conventionally, there is known a distance measuring device that scans an illumination light beam from a light source using a deflector and measures the distance to an object based on the time or phase until the illumination light beam is received after being reflected by the object. Patent Document 1 discloses an optical device that performs a first scan with an illumination light beam from a light source using a first deflector, and performs a second scan with a second deflector after the illumination light beam passes through a light guide optical system. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-170049 A Summary of the Invention [Problem to be solved by the invention]

[0004] When measuring the distance to a distant object using the optical device of Patent Document 1, it is necessary to increase the diameter of the beam of the reflected light in order to increase the amount of light incident on the optical device. In that case, it is necessary to increase the width of the deflection reflection surface of the first deflector in the direction parallel to the rotation axis, which makes it difficult to manufacture the first deflector and reduces durability due to the increased weight.

[0005] An object of the present invention is to provide an optical device that is compact yet ensures a sufficient scanning angle range for a first deflector. [Means for solving the problem]

[0006] An optical device according to one aspect of the present invention comprises a first optical system that guides illumination light from a light source, a first deflector that deflects the illumination light from the first optical system, a second optical system that guides the illumination light deflected by the first deflector, and a second deflector that deflects the illumination light from the second optical system, wherein the first deflector rotates about a first rotation axis and the second deflector rotates about a second rotation axis, the refractive power of the second optical system is different in a first cross section perpendicular to the first rotation axis and a second cross section parallel to the first rotation axis, and the illumination light from the first optical system is a convergent light in the second cross section. Effect of the Invention

[0007] According to the present invention, it is possible to provide an optical device that is compact yet capable of ensuring the scanning angle range of the first deflector. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a distance measuring device according to an embodiment of the present invention. [Diagram 2] 3 is a development view of the optical device in a first scanning section and a second scanning section. FIG. [Diagram 3] 4 is a diagram showing the relationship between the light flux diameter of an illumination light beam emitted from an optical device and the distance to an object in a first scanning section and a second scanning section. FIG. [Figure 4] 1 is a functional block diagram of an in-vehicle system according to an embodiment; [Diagram 5] 1 is a schematic diagram of a main portion of a vehicle according to an embodiment; [Figure 6] 4 is a flowchart showing an operation example of the in-vehicle system according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to refer to the same components, and duplicated descriptions will be omitted.

[0010] 1 is a schematic diagram of a distance measuring device 100 according to an embodiment of the present invention. The distance measuring device 100 includes an optical device 1, a control device 2, and a signal processing device 3.

[0011] The optical device 1 emits an illumination light beam (illumination light) in a desired angular direction to two-dimensionally scan a space, and receives a reflected light beam from an object 50 outside the optical device 1.

[0012] The control device 2 controls the light source 1001, the light receiving element 7004, the first deflector 20, and the second deflector 40, which are included in the optical device 1 and will be described later, at a predetermined drive voltage and drive frequency. For example, the control device 2 controls the light source 1001 to make the illumination light beam emitted from the light source 1001 into pulsed light, and rotates or oscillates the first deflector 20 and the second deflector 40 at a desired constant speed. The control device 2 is, for example, a processing device such as a CPU (Central Processing Unit) or an arithmetic device equipped with the same.

[0013] The signal processing device 3 acquires a signal from the light receiving element 7004, and acquires distance information to the object 50 based on the time from when the illumination light beam is emitted from the light source 1001 to when the reflected light beam is received by the light receiving element 7004. Note that instead of the time until the reflected light beam from the object 50 is received, the distance to the object 50 may be calculated by calculating the difference (phase difference) between the phase of the illumination light beam and the phase of the reflected light beam, and multiplying the phase difference by the speed of light.

[0014] In the following description, the first deflector 20 rotates around the first rotation axis 20A, and the second deflector 40 rotates around the second rotation axis 40A. Note that the rotation includes swinging (half rotation). The first scanning section (first section) is a section perpendicular to the first rotation axis 20A, and the second scanning section (second section) is a section perpendicular to the first scanning section (a section parallel to the first rotation axis 20A). Furthermore, the first rotation axis 20A and the second rotation axis 40A may be parallel to each other, but are preferably non-parallel to each other, and more preferably perpendicular to each other.

[0015] Fig. 2(a) shows a development of the optical device 1 in the first scanning section (XY section). Fig. 2(b) shows a development of the incident optical system (first optical system) 10 in the second scanning section (YZ section). Fig. 2(c) shows a development of the first deflector 20, the light guiding optical system (second optical system) 30, and the second deflector 40 in the second scanning section (ZX section). Fig. 2(d) shows a development of the beam branching element 60 and the light receiving optical system 70 in the second scanning section (ZX section).

[0016] The optical device 1 has an incident optical system 10, a first deflector 20, a light guiding optical system 30, a second deflector 40, a beam branching element 60, and a light receiving optical system 70. In the optical device 1, an illumination light beam from the incident optical system 10 is deflected and reflected (deflected) by the first deflector 20 at a first scanning cross section, passes through the light guiding optical system 30, and is then deflected and reflected (deflected) by the second deflector 40 at a second scanning cross section to illuminate an object 50. A reflected light beam from the object 50 travels along a reverse optical path, is deflected and reflected by the first deflector 20, is then reflected by the beam branching element 60, and is received by the light receiving optical system 70.

[0017] The incident optical system 10 includes a light source 1001, a collimator lens 1002, a first aperture stop 1003, a beam branching element 60, a wave plate 1004, and a cylindrical lens 1005, and guides an illumination light beam from the light source 1001. The first scanning section in the incident optical system 10 is a section that includes the optical axis of the illumination light beam from the light source 1001 and is perpendicular to the first rotation axis 20A. The second scanning section in the incident optical system 10 is a section that is perpendicular to the first scanning section in the incident optical system 10.

[0018] The light source 1001 emits an illumination light beam. The light source 1001 preferably emits light in the infrared wavelength range that has little effect on the human eye when it enters the human eye as the illumination light beam during distance measurement. In this embodiment, a semiconductor laser with a wavelength λ of 905 nm is used as the light source 1001. In this embodiment, the polarization of the illumination light beam emitted from the light source 1001 is linearly polarized light that is approximately parallel to the first scanning cross section.

[0019] The collimator lens 1002 converts the illumination light beam emitted from the light source 1001 into parallel light. However, the parallel light here is not limited to strictly parallel light, but includes approximately parallel light such as weakly divergent light or weakly convergent light.

[0020] The first aperture stop 1003 is a light blocking member that determines the light beam diameter by restricting the parallel illumination light beam. In this embodiment, the first aperture stop 1003 is rectangular in shape to match the far field pattern (FFP) of the illumination light beam emitted from the collimator lens 1002, but may be a shape other than rectangular.

[0021] The beam branching element 60 transmits the illumination beam from the light source 1001. In this embodiment, a polarizing beam splitter is used as the beam branching element 60, and transmits the illumination beam that is linearly polarized and parallel to the first scanning cross section emitted from the light source 1001.

[0022] The wave plate 1004 changes the polarization state of the illumination light beam incident on the wave plate 1004. In this embodiment, the wave plate 1004 is a ¼ λ wave plate, and changes the linearly polarized illumination light beam to circularly polarized light.

[0023] The cylindrical lens 1005 has a refractive power in the second scanning cross section, and guides the illumination light beam passing through the wave plate 1004 to the deflector 20 .

[0024] In this embodiment, the collimator lens 1002 and the cylindrical lens 1005 are made of resin, which is easy to manufacture into an aspheric shape, but the material is not limited to this and may be glass or other materials.

[0025] The optical members described above (the collimator lens 1002, the first aperture stop 1003, the beam splitter 60, the wave plate 1004, and the cylindrical lens 1005) are not limited to the configuration of this embodiment. If necessary, the arrangement of each member may be changed, or each member may be integrated, for example, by integrating the collimator lens 1002 and the cylindrical lens 1005.

[0026] The first deflector 20 and the second deflector 40 rotate or swing about a rotation axis by a driving means such as a motor (not shown), and deflectively reflect the illumination light beam incident on the deflection reflection surface (deflection surface) of each deflector.

[0027] In this embodiment, the first deflector 20 deflects and reflects the illumination light emitted from the incident optical system 10 at the deflecting reflection surface 2001, and scans the first scanning cross section. The second deflector 40 deflects and reflects the illumination light guided by the light-guiding optical system 30 at the deflecting reflection surface 4001, and scans the illumination light at the second scanning cross section. The illumination light deflected and reflected by the second deflector 40 illuminates the object 50.

[0028] In this embodiment, the first deflector 20 is a polygon mirror, and the second deflector 40 is a galvanometer mirror. However, the first deflector 20 and the second deflector 40 are not limited to this, and may be, for example, a polygon mirror, a galvanometer mirror, a MEMS (Micro Electro Mechanical Systems) mirror, or the like.

[0029] The light-guiding optical system 30 includes a plurality of optical elements and guides the illumination light beam from the first deflector 20 to the second deflector 40. The illumination light beam emitted from the light-guiding optical system 30 is parallel light in both the first scanning section and the second scanning section. However, the parallel light here is not limited to strictly parallel light, but includes approximately parallel light such as weakly divergent light and weakly convergent light. In this embodiment, the light-guiding optical system 30 is composed of a first lens 3001, a second lens 3002, and a third lens 3003, but is not limited thereto. In this embodiment, the light-guiding optical system 30 is made of resin, but is not limited thereto, and may be made of glass or other materials.

[0030] The light reflected from the object 50 is deflected and reflected by the second deflector 40, passes through the light guiding optical system 30, and is deflected and reflected by the first deflector 20. The light deflected and reflected by the first deflector 20 enters the wave plate 1004 and changes its polarization state.

[0031] The wave plate 1004 is a ¼λ wave plate in this embodiment as described above, and can change a reflected linearly polarized light beam into a circularly polarized light beam, or change a reflected circularly polarized light beam into a linearly polarized light beam.

[0032] The reflected light beam passing through the wave plate 1004 is guided to the light receiving optical system 70 by the light beam branching element 60. In this embodiment, the light beam branching element 60 is a polarizing beam splitter as described above, and reflects the linearly polarized light component perpendicular to the first scanning cross section of the reflected light beam passing through the wave plate 1004. In this embodiment, the light beam branching element 60 is not limited to a polarizing beam splitter, and a beam splitter, a prism, or a perforated mirror may be used. A perforated mirror is a mirror having an opening. The illumination light beam from the light source 1001 passes through the opening, and the reflected light beam is guided to the light receiving optical system 70 by a reflecting portion other than the opening area. When these elements are used as the light beam branching element 60, the incident optical system 10 does not need to include the wave plate 1004.

[0033] The light receiving optical system 70 includes a beam splitter 60 , a second aperture stop 7001 , an optical filter 7002 , a condenser lens 7003 , and a light receiving element 7004 .

[0034] The second aperture stop 7001 determines the diameter of the light beam by restricting the reflected light.

[0035] The optical filter 7002 is a bandpass filter that transmits only reflected light rays in a wavelength band corresponding to the illumination light rays emitted from the light source 1001. In this embodiment, the optical filter 7002 is configured to transmit only reflected light rays with a wavelength λ of 905±10 nm.

[0036] The condenser lens 7003 converts the reflected light transmitted through the optical filter 7002 into convergent light and guides it to the light receiving element 7004. In this embodiment, the condenser lens 7003 is made of resin, but is not limited to this and may be made of glass or other materials.

[0037] The light receiving element 7004 is an element for receiving the reflected light from the condenser lens 7003, photoelectrically converting it, and outputting a signal. In this embodiment, the light receiving element 7004 uses an APD (Avalanche Photo Diode), but a PD (Photo Diode) or a SPAD (Single Photon Avalanche Diode) may also be used.

[0038] The optical components described so far (second aperture stop 7001, optical filter 7002, and condenser lens 7003) are not limited to those in this embodiment, and the arrangement of each component may be interchanged as necessary.

[0039] The optical device 1 can be configured as a coaxial system in which the optical axes of the illumination light beam from the light source 1001 and the reflected light beam from the object 50 partially coincide with each other, or as a non-coaxial system in which the optical axes do not coincide with each other. In this embodiment, the optical device 1 is configured as a coaxial system that includes a beam branching element 60 and coincides the optical axes of the illumination light beam and the reflected light beam in a part of the incident optical system 10, the second deflector 20, the light guiding optical system 30, and the second deflector 40, thereby reducing the number of optical members and making the optical device 1 more compact.

[0040] Here, the characteristics of the optical device 1 are shown in Tables 1, 2, and 3 below.

[0041] [Table 1]

[0042] [Table 2]

[0043] [Table 3]

[0044] In Tables 1, 2, and 3, the direction parallel to the optical axis of the illumination light beam and the reflected light beam is defined as the X direction, the direction within the first scanning cross section perpendicular to the X axis is defined as the Y axis, and the direction perpendicular to the Y axis and Z axis is defined as the X axis.

[0045] In addition, the "*" in Tables 1 and 2 indicates the incident surface and the exit surface for the reflected light.

[0046] Also, in Tables 2 and 3, "Ex" means "×10^(-x)".

[0047] The aspheric shape of each lens surface of the collimator lens 1002, the cylindrical lens 1005, and the condenser lens 7003 in this embodiment is expressed by the following formula (1).

[0048]

number

[0049] (1) Here, r is the radius of curvature, k is the eccentricity, and ci, cip (i=1, 2, 3, 4) are aspheric coefficients. Note that the subscripts y and z indicate variables on the y-axis and z-axis, respectively.

[0050] The diffractive surface shape of each lens surface of the collimator lens 1002, the cylindrical lens 1005, and the condenser lens 7003 in this embodiment is expressed by the following formula (2).

[0051]

number

[0052] (2) Here, φ is the phase function of the diffractive surface, and ci (i=1, 2, 3, 4) are the phase function coefficients.

[0053] The aspheric shape (meridional shape) of each of the lens surfaces of the first lens 3001, the second lens 3002, and the third lens 3003 in this embodiment in the first scanning cross section is expressed by the following formula (3).

[0054]

number

[0055] (3) Here, R is the radius of curvature, k is the eccentricity, and Bi (i=4, 6, 8, 10, 12) is the aspheric coefficient. When the coefficient Bi is different between the positive and negative sides of the y-axis, as shown in Table 3, the coefficient on the positive side is given the subscript u (i.e., Biu), and the coefficient on the negative side is given the subscript l (i.e., Bil).

[0056] Moreover, the aspheric shape (sagittal shape) of each of the lens surfaces of the first lens 3001, the second lens 3002, and the third lens 3003 in the second scanning cross section is expressed by the following formula (4).

[0057]

number

[0058] (4) Here, Mjk (j=0 to 12, k=1) is an aspheric coefficient.

[0059] In this embodiment, the sagittal tilt amount refers to M01. Therefore, a sagittal tilt surface refers to a surface where M01 is not 0, and a sagittal tilt changing surface refers to a surface where at least one of Mj1 (j=1 to 12) is not 0.

[0060] Moreover, the radius of curvature r' in the second scanning cross section changes continuously according to the y coordinate of the lens surface as shown in the following formula (5).

[0061]

number

[0062] (5) Here, r is the radius of curvature on the optical axis, E j (j=1~8) is the variation coefficient.

[0063] In this embodiment, the incident optical system 10 uses a cylindrical lens 1005 having a positive refractive power in the second scanning cross section, so that the illumination light beam emitted from the incident optical system 10 becomes a convergent light in the second scanning cross section.

[0064] In addition, the light-guiding optical system 30 is an optical element (having an axially asymmetric shape) having different refractive powers in the first scanning cross section and the second scanning cross section, so that the emitted illumination light beam is shaped independently in the first scanning cross section and the second scanning cross section.

[0065] In this embodiment, the illumination light is converted into parallel light and emitted in both the first and second scanning cross sections. However, the parallel light here is not limited to strictly parallel light, but includes approximately parallel light such as weakly divergent light and weakly convergent light.

[0066] With the above configuration, the width of the deflection reflection surface 2001 in the direction parallel to the first rotation axis 20A of the first deflector 20 that deflects and reflects the illumination light beam emitted from the incident optical system 10 can be reduced, thereby making the first deflector more compact.

[0067] At this time, in the first scanning cross section, the first deflector 20 (its deflection reflection surface 2001) and the second deflector (its deflection reflection surface 4001) are in an optically conjugate relationship, thereby ensuring the scanning angle range of the first deflector 20 and maintaining the compact size of the second deflector.

[0068] The amount of light reflected from the object 50 is very weak. In this embodiment, in order to measure the object 50 located far away (about 150 m) from the optical device 1, the incident beam diameter of the reflected beam needs to be 10 mm or more in both the first scanning cross section and the second scanning cross section. Therefore, the width of the deflection reflection surface 4001 in the first scanning cross section of the second deflector 40 is approximately equal to the beam diameter in the first scanning cross section of the illumination beam emitted from the light guiding optical system 30 and the incident beam diameter of the desired reflected beam, and is 12 mm.

[0069] Here, consider a case where an optical element (with an axially symmetric shape) having the same refractive power in the first scanning section and the second scanning section is used in the light guide optical system 30. In order to convert the illumination light beam into a substantially parallel light beam while making the first deflector 20 and the second deflector 40 have an optically conjugate relationship, it is necessary to ensure that the light flux diameter of the illumination light beam is 10 mm or more on the deflection reflection surface 2001 of the first deflector 20 in both the first scanning section and the second scanning section. In this case, it is difficult to reduce the width of the deflection reflection surface 2001 in the direction parallel to the first rotation axis 20A of the first deflector 20 and sufficiently reduce the size of the first deflector 20 as in this embodiment.

[0070] In order to guide the illumination light from the light source 1001 to the object without loss and to capture as much reflected light from the distant object 50 as possible, it is preferable to increase the width of the deflection reflection surfaces of the first deflector 20 and the second deflector 40. However, increasing the size of the first deflector 20 and the second deflector 40 makes manufacturing difficult and reduces durability.

[0071] In this embodiment, the incident light is converged at the second scanning cross section, and the light guiding optical system 30 is provided, thereby making it possible to reduce the size of the first deflector 20.

[0072] The lens surfaces of first lens 3001, second lens 3002, and third lens 3003 are aspheric, but may be spherical.

[0073] Furthermore, each of the lens surfaces of the first lens 3001, the second lens 3002, and the third lens 3003 does not have to have a refractive power in the second scanning cross section.

[0074] In addition, the optical conjugate relationship between the first deflector 20 and the second deflector 40 is not completely conjugate because the position of the rotation axis of the deflector and the position of the deflection reflection surface of the deflector differ slightly, and there is a possibility that some positional misalignment occurs.

[0075] According to this embodiment, the width of the deflection reflection surface 2001 in the direction parallel to the first rotation axis 20A of the first deflector 20 is 2 mm.

[0076] The width of the incident light beam diameter of the reflected light beam in the first scanning cross section and the second scanning cross section is 10 mm.

[0077] If the configuration of this embodiment is not used, the width of the deflection reflection surface 2001 in the direction parallel to the first rotation axis 20A of the first deflector 20 must be 10 mm or more. In this case, the volume ratio becomes 5 times or more, making manufacturing difficult.

[0078] As described above, when measuring a distant object 50, it is preferable for the distance measuring device to increase the diameter of the incident light beam in order to increase the amount of reflected light. In this case, when the width of the deflection reflection surface 2001 of the deflector 20 is determined according to the diameter of the incident light beam, a relatively large deflector 20 is used. According to this embodiment, the first deflector 20 can be made compact regardless of the diameter of the incident light beam. In other words, the manufacturing is easier than when the deflector 20, which is already small, is further made compact.

[0079] As described above, by making the first deflector 20 smaller, it is possible to simplify the manufacturing process, reduce the weight of the first deflector 20, and improve the durability. <Width of the deflection reflecting surface of the deflector> In this embodiment, when the width of the deflection reflecting surface 2001 of the first deflector 20 in the direction parallel to the first rotation axis 20A is a and the width of the deflection reflecting surface 4001 of the second deflector 40 in the direction parallel to the second rotation axis 40A is b, the width a is 2 mm and the width b is 12 mm. In other words, the width of the deflection reflecting surface 2001 of the first deflector 20 in the direction parallel to the first rotation axis 20A is smaller than the width of the deflection reflecting surface 4001 of the second deflector 40 in the direction parallel to the second rotation axis 40A.

[0080] Here, the width a can be determined from the viewpoints of the manufacturing method, manufacturing cost, and durability of the deflector, regardless of the beam diameter of the illumination light beam emitted from the optical device 1 and the beam diameter of the reflected light beam captured by the optical device 1. <Optical conjugation using light guide optical system> In this embodiment, the light guiding optical system 30 is an optical system that does not have a refractive power in the first scanning cross section, but the first to third lenses 3001 to 3003 that constitute the light guiding optical system 30 have a refractive power. In addition, the light guiding optical system 30 is an optical system that has a positive refractive power in the second scanning cross section and converts the illumination light beam deflected and reflected by the first deflector 20 from divergent light to parallel light. However, the parallel light here is not limited to strictly parallel light, but includes approximately parallel light such as weakly divergent light and weakly convergent light. Therefore, the light guiding optical system 30 is configured such that the first deflector 20 and the second deflector 40 are in an optically conjugate relationship in the first scanning cross section, and the first deflector 20 and the second deflector 40 are not in an optically conjugate relationship in the second scanning cross section. As a result, as described above, it is possible to achieve a compact first deflector 20 while maintaining a compact second deflector 40, and to make the illumination light beam approximately parallel in both the first scanning section and the second scanning section.

[0081] In addition, in this embodiment, as described above, the illumination light beam can be shaped independently for the first scanning section and the second scanning section. Therefore, the divergence angle of the illumination light beam emitted from the optical device 1 can be further reduced, and sufficient illuminance and angular resolution can be ensured even when the object 50 is located far away. Here, the divergence angle represents the angle between the illumination light beams at both ends in the direction perpendicular to the optical axis.

[0082] FIG. 3 is a diagram showing the relationship between the light flux diameter of the illumination light beam emitted from the optical device 1 in the first scanning section and the second scanning section and the distance to the object 50. As shown in FIG.

[0083] FIG. 3(a) shows the relationship between the beam diameter of the illumination light beam in the first scanning section and the second scanning section and the distance to the object 50 in the standard state (ambient temperature: 20° C.). The beam diameter of the illumination light beam represents the maximum beam diameter in terms of geometrical optics in both the first scanning section and the second scanning section. FIG. 3(a) also plots the relationship between the beam diameter and the distance to the object 50 that achieves an angular resolution of 1.5°. The illumination light beam emitted from the optical device 1 has a divergence angle, so that the beam diameter of the illumination light beam changes with respect to the distance to the object 50, and the divergence angle in this embodiment is 1.5° in the standard state (ambient temperature: 20° C.). The angular resolution represents the minimum angle at which the beams do not overlap (can be resolved) in adjacent illumination regions, and is 1.5°, which is equal to the divergence angle.

[0084] Fig. 3(b) is a diagram showing the relationship between the light beam diameter of the first scanning cross section and the second scanning cross section of the illumination light beam in a state where the environmental temperature changes (environmental temperature: 85°C) and the distance to the object 50. Fig. 2(b) also plots the relationship between the light beam diameter and the distance to the object 50 to achieve an angular resolution of 3.0°. In this embodiment, the spread angle is 3.0° in a state where the environmental temperature changes (environmental temperature: 85°C), and the angular resolution is about 3.0°.

[0085] As a result, in this embodiment, the spread angle of the illumination light beam is 0.3° or less in both the first scanning section and the second scanning section, and the angular resolution is 0.3° or less. Here, the angular resolution of 0.3° is a performance that allows an object 50 of about 50 cm in size located 100 m ahead of the optical device 1 to be recognized separately from adjacent measuring points (areas).

[0086] In this embodiment, in the first scanning cross section of the light-guiding optical system 30, the light beam diameter on the deflection reflection surface 2001 of the first deflector 20 is equal to the light beam diameter on the deflection reflection surface 4001 of the second deflector 40. As a result, the scanning angle range of the illumination light beam by the first deflector 20 matches the scanning angle range of the illumination light beam emitted from the optical device 1 in the first scanning cross section.

[0087] However, the optical system may be an optical system that expands the beam diameter of the illumination light beam from the first deflector 20 and reduces the beam diameter of the reflected light beam from the second deflector 40, or an optical system that reduces the beam diameter of the illumination light beam from the first deflector 20 and reduces the beam diameter of the reflected light beam from the second deflector 40. In this case, the scanning angle range of the first scanning cross section of the illumination light beam emitted from the optical device 1 does not match the scanning angle range of the illumination light beam by the first deflector 20, and is determined by the angular magnification of the light-guiding optical system 30. <Refractive power of the incident optical system> In this embodiment, the incident optical system 10 is an optical system having different refractive powers in the first scanning section and the second scanning section. Specifically, the incident optical system 10 is an optical system having a positive refractive power that converts the illumination light beam from the light source 1001 into parallel light in the first scanning section and into convergent light in the second scanning section. However, the parallel light here is not limited to strictly parallel light, but includes approximately parallel light such as weakly divergent light and weakly convergent light.

[0088] In this embodiment, the incident optical system 10 focuses the illumination light beam near the first deflector 20 in the second scanning cross section, thereby minimizing the width of the first deflector 20 in the direction parallel to the first rotation axis 20A, thereby making it possible to miniaturize the first deflector 20. <Lens configuration of light guide optical system> In this embodiment, the light guide optical system 30 is composed of three or more optical elements. If each optical element is decentered in the first scanning section and the second scanning section due to an assembly error, an external factor, or the like, the incident positions of the illumination light beam and the reflected light beam incident on each optical element change. In particular, when the scanning angle range of the illumination light beam by the first deflector 20 is wide, these changes become large. Here, the scanning angle range of the first deflector 20 represents the maximum angle formed by the respective principal rays of the illumination light beam among the illumination light beams scanned by the first deflector 20 in the first scanning section. Moreover, the scanning angle range of the second deflector 40 represents the maximum angle formed by the respective principal rays of the illumination light beam among the illumination light beams scanned by the second deflector 40 in the second scanning section.

[0089] When the scanning angle range of the first deflector 20 is 60° or more, if the light guide optical system 30 is composed of two lenses, the curvature of each lens surface needs to be increased, and accordingly, the spread angle tends to increase with a small change in the incident position of the light beam. In addition, the thickness of each lens also increases, making manufacturing difficult.

[0090] Therefore, in this embodiment, when the scanning angle range of the first deflector 20 is 60° or more, the three-lens configuration of the first to third lenses 3001, 3002, and 3003 reduces the curvature of each lens surface and suppresses an increase in the thickness of each lens.

[0091] Furthermore, when the scanning angle range of the first deflector 20 is 60° or more, in order to secure a sufficient reflection area for the illumination light within the scanning angle range, it is necessary to set the width of the deflecting reflection surface 2001 of the first deflector 20 large in the first scanning cross section. Therefore, as described above, the first deflector 20 becomes large, and therefore, in terms of simplifying the manufacturing, a large effect can be obtained. <Lens arrangement of light guide optical system> In this embodiment, it is preferable that the first to third lenses 3001, 3002, and 3003 have front-to-back symmetric shapes with respect to the optical axis in order to balance the aberrations occurring at the lens surfaces in the first scanning cross section of the light-guiding optical system 30. The light-guiding optical system 30 forms an intermediate image in the first scanning cross section, and the second lens 3002 is disposed near the position where the intermediate image is formed in the first scanning cross section. <Reducing the effects of impurities> When an optical element contains impurities or has foreign matter attached thereto, the amount of light passing through the optical element may be lost, and the degree of contribution varies depending on the ratio of the luminous flux diameter of the light passing through the optical element to the size of the impurities. Generally, the impurities or attached matter are minute, so if the luminous flux diameter of the light passing through the optical element is large, the impact is minor, but if the optical element is placed on the focusing surface of the light, the impact may be significant.

[0092] In this embodiment, since the light guiding optical system 30 does not form an intermediate image in the second scanning cross section, the light beam diameter in the vicinity of the position where the intermediate image is formed is larger than when the intermediate image is formed in both cross sections. In other words, it is possible to suppress the loss of the light amount of the illumination light beam and the reflected light beam when a foreign object adheres. <Direction of light source arrangement in incident optical system> In this embodiment, the light source 1001 has different light-emitting surface widths in the first scanning section and the second scanning section. Accordingly, the illumination light beam emitted from the light source 1001 has a large spread angle in a section where the light-emitting surface width is small, and a small spread angle in a section where the light-emitting surface width is large. Here, the spread angle is an angle indicating the spread angle of the illumination light beam immediately after being emitted from the light source 1001, and is different from the spread angle of the illumination light beam emitted from the optical device 1.

[0093] Considering the illumination light passing through the light guide optical system 30, the optical performance of the first scanning section is more susceptible to a small change in the incident position of the illumination light entering the optical system than the optical performance of the second scanning section. Therefore, in this embodiment, the light source 1001 is arranged so that the section (1001P) with a small light emitting surface width coincides with the first scanning section, and the section (1001S) with a large light emitting surface width coincides with the second scanning section. As described above, the spread angle of the illumination light emitted from the light source 1001 is large in the first scanning section and small in the second scanning section. This makes it possible to suppress the influence of the change in the incident position of the chief ray of the illumination light due to the light emitting surface width of the light source 1001 having a finite size. <Adding a diffractive surface to the incident optical system> In this embodiment, the collimator lens 1002 and the cylindrical lens 1005 have diffractive surfaces in the incident optical system 10. This makes it possible to reduce the effect on optical performance even when the environmental temperature changes.

[0094] In this embodiment, plastic lenses are used for the incident optical system 10 and the light guiding optical system 30, and it has been confirmed that the spread angle of the illumination light tends to deteriorate when the environmental temperature changes. This is mainly due to the change in the refractive index of the plastic lens and the change in the wavelength of the semiconductor laser.

[0095] In this embodiment, the divergence (convergence) of the illumination light beam caused by the change in refractive index of the resin lens due to a change in the environmental temperature and the change in wavelength of the semiconductor laser is canceled out by the convergence (divergence) of the illumination light beam caused by the change in wavelength of the semiconductor laser and a lens with a diffractive surface.

[0096] Specifically, by providing the collimator lens 1002 and the cylindrical lens 1005 with diffractive surfaces having appropriate refractive power, the divergence angle of the illumination light beam can be suppressed to 0.3° or less in both the first scanning cross section and the second scanning cross section even when the environmental temperature changes. Note that the collimator lens 1002 and the cylindrical lens 1005 are provided with diffractive surfaces having different refractive powers in the first scanning cross section and the second scanning cross section, and the optical performance of the illumination light beam can be controlled independently in each scanning cross section.

[0097] The diffractive surface is designed with a reference wavelength λ of 905 nm. In this embodiment, the incident side of the collimator lens 1002 and the exit side of the cylindrical lens 1005 with respect to the illumination light are diffractive surfaces, but this is not limiting. Also, a diffractive surface may be provided on either one of them. [In-vehicle system] Fig. 4 is a configuration diagram of an on-board camera 810 according to this embodiment and an on-board system (control system, driving support device) 800 including the same. The on-board system 800 is held by a movable body (mobile device) such as an automobile (vehicle), and is a system for supporting driving (piloting) of the vehicle based on image information of the surroundings of the vehicle acquired by the on-board camera 810. Fig. 5 is a schematic diagram of a vehicle 900 as a mobile device including the on-board system 800. Fig. 5 shows a case where an imaging range 850 of the on-board camera 810 is set in front of the vehicle 900, but the imaging range 850 may be set to the rear or side of the vehicle 900.

[0098] 4, the vehicle-mounted system 800 includes an in-vehicle camera 810, a vehicle information acquisition device 820, a control device (control unit, ECU: electronic control unit) 830, and a warning device (warning unit) 840. The in-vehicle camera 810 also includes an imaging unit 81, an image processing unit 82, a parallax calculation unit 83, a distance acquisition unit (acquisition unit) 84, and a collision determination unit 85. The image processing unit 82, the parallax calculation unit 83, the distance acquisition unit 84, and the collision determination unit 85 constitute a processing unit. The imaging unit 81 includes an optical system according to any one of the above-mentioned embodiments, and an imaging element.

[0099] 6 is a flowchart showing an example of the operation of the in-vehicle system 800 according to this embodiment. The operation of the in-vehicle system 800 will be described below with reference to this flowchart.

[0100] First, in step S1, an object (subject) such as an obstacle or a pedestrian around the vehicle is captured by the imaging unit 81, and a plurality of image data (parallax image data) are acquired.

[0101] In step S2, vehicle information is acquired by the vehicle information acquisition device 820. The vehicle information includes the vehicle speed, yaw rate, steering angle, and the like.

[0102] In step S3, the image processing unit 82 performs image processing on the multiple image data acquired by the imaging unit 81. Specifically, image feature analysis is performed to analyze feature quantities such as the amount and direction of edges in the image data and density values. Here, the image feature analysis may be performed on each of the multiple image data, or may be performed on only some of the multiple image data.

[0103] In step S4, disparity (image shift) information between the multiple image data acquired by the imaging unit 81 is calculated by the disparity calculation unit 83. Since a known method such as the SSDA method or the area correlation method can be used as a method for calculating disparity information, a description thereof will be omitted in this embodiment. Note that steps S2, S3, and S4 may be performed in the above order, or may be processed in parallel with each other.

[0104] In step S5, distance acquisition unit 84 acquires (calculates) distance information about the object captured by imaging unit 81. The distance information can be calculated based on the parallax information calculated by parallax calculation unit 83 and the internal and external parameters of imaging unit 81. Note that the distance information here refers to information about the relative position of the object, such as the distance from the object, the defocus amount, and the image shift amount, and may directly represent the distance value of the object in the image or indirectly represent information corresponding to the distance value.

[0105] Then, in step S6, the collision determination unit 85 uses the vehicle information acquired by the vehicle information acquisition device 820 and the distance information calculated by the distance acquisition unit 84 to determine whether the distance to the object is within a preset range of a set distance. This makes it possible to determine whether an object exists within a set distance around the vehicle and to determine the possibility of a collision between the vehicle and the object. If an object exists within the set distance, the collision determination unit 85 determines that there is a "possibility of collision" (step S7), and if there is no object within the set distance, it determines that there is no "possibility of collision" (step S8).

[0106] Next, when the collision determination unit 85 determines that there is a "possibility of collision," it notifies (transmits) the determination result to the control device 830 and the warning device 840. At this time, the control device 830 controls the vehicle based on the determination result by the collision determination unit 85 (step S6), and the warning device 840 issues a warning to the user of the vehicle (driver, passengers) based on the determination result by the collision determination unit 85 (step S7). Note that the notification of the determination result may be sent to at least one of the control device 830 and the warning device 840.

[0107] The control device 830 can control the movement of the vehicle by outputting control signals to the driving parts (engine, motor, etc.) of the vehicle. For example, the control device 830 performs control such as applying the brakes in the vehicle, releasing the accelerator, turning the steering wheel, and generating control signals to generate braking forces in each wheel to suppress the output of the engine or motor. The warning device 840 also warns the user by, for example, issuing a warning sound (alarm), displaying warning information on the screen of a car navigation system, etc., and applying vibrations to the seat belt or steering wheel.

[0108] As described above, the in-vehicle system 800 according to this embodiment can effectively detect an object by the above-mentioned processing, and it becomes possible to avoid a collision between the vehicle and the object. In particular, by applying the optical system according to each of the above-mentioned embodiments to the in-vehicle system 800, it becomes possible to detect an object and judge a collision over a wide angle of view while miniaturizing the entire in-vehicle camera 810 and increasing the degree of freedom of arrangement.

[0109] Note that various embodiments are possible for calculating the distance information. As an example, a case will be described in which a pupil division type image sensor having a plurality of pixel units regularly arranged in a two-dimensional array is adopted as the image sensor of the image sensor 81. In the pupil division type image sensor, one pixel unit is composed of a microlens and a plurality of photoelectric conversion units, and can receive a pair of light beams passing through different regions in the pupil of the optical system, and output a pair of image data from each photoelectric conversion unit.

[0110] Then, the image shift amount of each region is calculated by a correlation calculation between paired image data, and image shift map data representing the distribution of the image shift amount is calculated by the distance acquisition unit 84. Alternatively, the distance acquisition unit 84 may further convert the image shift amount into a defocus amount to generate defocus map data representing the distribution of the defocus amount (distribution on a two-dimensional plane of the captured image). The distance acquisition unit 84 may also acquire distance map data of the distance to the object converted from the defocus amount.

[0111] Furthermore, the in-vehicle system 800 and the mobile device 900 may be provided with a notification device (notification unit) for notifying a manufacturer of the in-vehicle system or a dealer of the mobile device when the mobile device 900 collides with an obstacle. For example, the notification device may be one that transmits information (collision information) related to the collision between the mobile device 900 and an obstacle to a preset external notification destination by e-mail or the like.

[0112] In this way, by adopting a configuration in which the notification device automatically notifies collision information, it is possible to promptly take measures such as inspection and repair after a collision occurs. The destination of the collision information may be an insurance company, a medical institution, the police, or any other entity set by the user. The notification device may be configured to notify the destination of not only collision information but also information on failure of each component and information on consumption of consumables. The detection of the presence or absence of a collision may be performed using distance information or may be performed by another detection unit (sensor).

[0113] In this embodiment, the in-vehicle system 800 is applied to driving assistance (collision damage reduction), but the in-vehicle system 800 may be applied to cruise control (including full-speed following function) and automatic driving. The in-vehicle system 800 is not limited to vehicles such as automobiles, but may be applied to moving bodies such as ships, aircraft, and industrial robots. The in-vehicle system 800 is not limited to moving bodies, but may be applied to various devices that use object recognition such as an intelligent transport system (ITS).

[0114] The disclosure of this embodiment includes the following configuration. (Configuration 1) A first optical system that guides illumination light from a light source; a first deflector that deflects the illumination light from the first optical system; a second optical system that guides the illumination light deflected by the first deflector; a second deflector that deflects the illumination light from the second optical system; the first deflector rotates about a first axis of rotation; the second deflector rotates about a second axis of rotation; a refractive power of the second optical system is different between a first cross section perpendicular to the first rotation axis and a second cross section parallel to the first rotation axis; An optical device, characterized in that the illumination light from the first optical system is a converging light at the second cross section. (Configuration 2) The optical device described in configuration 1, characterized in that the width of the deflection surface of the first deflector in a direction parallel to the first rotation axis is smaller than the width of the deflection surface of the second deflector in a direction parallel to the second rotation axis. (Configuration 3) 3. The optical device according to configuration 1 or 2, wherein the illumination light from the second optical system is parallel light at the first cross section and the second cross section. (Configuration 4) The optical device described in any one of configurations 1 to 3, characterized in that the second optical system has the first deflector and the second deflector in an optically conjugate relationship at the first cross section, and the first deflector and the second deflector not in an optically conjugate relationship at the second cross section. (Configuration 5) 5. The optical device according to any one of configurations 1 to 4, wherein the second optical system has no refractive power in the first cross section and has positive refractive power in the second cross section. (Configuration 6) An optical device described in any one of configurations 1 to 5, characterized in that the second optical system forms an intermediate image at the first cross section and does not form an intermediate image at the second cross section. (Configuration 7) 7. The optical device according to any one of configurations 1 to 6, wherein the refractive power of the first optical system is different between the first cross section and the second cross section. (Configuration 8) 8. The optical device according to any one of configurations 1 to 7, wherein the illumination light from the first optical system is parallel light at the first cross section. (Configuration 9) An optical device described in any one of configurations 1 to 8, characterized in that the first optical system focuses the illumination light from the light source near the deflection surface of the first deflector at the second cross section. (Configuration 10) 10. The optical device of any one of configurations 1 to 9, wherein the first and second rotation axes are non-parallel to each other. (Configuration 11) 11. The optical device according to any one of configurations 1 to 10, wherein the second optical system has an optical element in the vicinity of a position where an intermediate image is formed in the first cross section. (Configuration 12) 12. The optical device according to any one of configurations 1 to 11, wherein the scanning angle range of the illumination light by the first deflector is 60° or more. (Configuration 13) 13. The optical device according to any one of configurations 1 to 12, wherein a light emitting surface width of the light source in the second scanning cross section is larger than a light emitting surface width of the light source in the first scanning cross section. (Configuration 14) 14. The optical device according to any one of configurations 1 to 13, wherein the entrance optical system comprises at least one diffractive surface. (Configuration 15) The optical device described in any one of configurations 1 to 14, characterized in that the second deflector deflects reflected light from an object illuminated by the illumination light, the second optical system guides the reflected light from the second deflector to the first deflector, the first deflector deflects the reflected light from the second optical system, and the first optical system guides the reflected light from the first deflector to a light receiving unit. (Configuration 16) A control system comprising: an optical device according to any one of configurations 1 to 15; and a judgment unit that judges the possibility of a collision with an object based on distance information of the object acquired by the optical device. (Configuration 17) 17. The control system according to claim 16, further comprising a control device that outputs a control signal to generate a braking force to a drive unit of the moving device when it is determined that there is a possibility of a collision between the vehicle and the object. (Configuration 18) 17. The control system according to configuration 16, further comprising a warning device that issues a warning to a user of the mobile device when it is determined that there is a possibility of a collision between the mobile device and the object. (Configuration 19) 17. The control system according to configuration 16, further comprising a notification unit that notifies an outside party of information regarding a collision between the mobile device and the object. (Configuration 20) A moving device comprising the optical device according to configuration 1 or 2, and capable of holding and moving the optical device. (Configuration 21) 21. The moving device according to configuration 20, further comprising a determination unit that determines the possibility of a collision with the object based on distance information of the object obtained by the optical device. (Configuration 22) 22. The moving device according to configuration 21, further comprising a control unit that outputs a control signal for controlling movement when it is determined that there is a possibility of a collision with the object. (Configuration 23) 22. The mobile device according to configuration 21, further comprising a warning unit that issues a warning to a user of the mobile device when it is determined that there is a possibility of a collision with the object. (Configuration 24) 22. The moving device according to claim 21, further comprising a notification unit that notifies an outside party of information regarding the collision with the object.

[0115] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0116] 1 Optical device 10 Incident optical system (first optical system) 20 First deflector 30 Light guide optical system (second optical system) 40 Second deflector

Claims

1. A first optical system that guides illumination light from a light source; a first deflector that deflects the illumination light from the first optical system; a second optical system that guides the illumination light deflected by the first deflector; a second deflector that deflects the illumination light from the second optical system; the first deflector rotates about a first axis of rotation; the second deflector rotates about a second axis of rotation; a refractive power of the second optical system is different between a first cross section perpendicular to the first rotation axis and a second cross section parallel to the first rotation axis; An optical device, characterized in that the illumination light from the first optical system is a converging light at the second cross section.

2. 2. The optical device according to claim 1, wherein a width of the deflection surface of the first deflector in a direction parallel to the first rotation axis is smaller than a width of the deflection surface of the second deflector in a direction parallel to the second rotation axis.

3. 3. The optical device according to claim 1, wherein the illumination light from the second optical system is parallel light at the first cross section and the second cross section.

4. 3. The optical device according to claim 1, wherein the second optical system has the first deflector and the second deflector in an optically conjugate relationship at the first cross section, and the first deflector and the second deflector not in an optically conjugate relationship at the second cross section.

5. 3. The optical device according to claim 1, wherein the second optical system has no refractive power in the first cross section and has positive refractive power in the second cross section.

6. 3. The optical device according to claim 1, wherein the second optical system forms an intermediate image at the first cross section and does not form an intermediate image at the second cross section.

7. 3. The optical device according to claim 1, wherein the refractive power of the first optical system is different between the first cross section and the second cross section.

8. 3. The optical device according to claim 1, wherein the illumination light from the first optical system is parallel light in the first cross section.

9. 3. The optical device according to claim 1, wherein the first optical system focuses the illumination light from the light source near a deflection surface of the first deflector in the second cross section.

10. 3. The optical device according to claim 1, wherein the first and second rotation axes are non-parallel to each other.

11. 3. The optical device according to claim 1, wherein the second optical system includes an optical element located near a position where an intermediate image is formed in the first cross section.

12. 3. The optical device according to claim 1, wherein a scanning angle range of the illumination light by the first deflector is 60 degrees or more.

13. 3. The optical device according to claim 1, wherein a light emitting surface width of the light source in the second cross section is larger than a light emitting surface width of the light source in the first cross section.

14. 3. The optical device according to claim 1, wherein the first optical system comprises a diffractive surface.

15. 3. The optical device according to claim 1, wherein the second deflector deflects reflected light from an object illuminated by the illumination light, the second optical system guides the reflected light from the second deflector to the first deflector, the first deflector deflects the reflected light from the second optical system, and the first optical system guides the reflected light from the first deflector to a light receiving unit.

16. 3. A control system comprising: the optical device according to claim 1; and a determination unit that determines a possibility of a collision with an object based on distance information of the object acquired by the optical device.

17. 17. The control system according to claim 16, further comprising a control device that outputs a control signal to generate a braking force in a drive unit of the moving device when it is determined that there is a possibility of a collision between the vehicle and the object.

18. 17. The control system according to claim 16, further comprising a warning device that issues a warning to a user of the mobile device when it is determined that there is a possibility of a collision between the mobile device and the object.

19. 17. The control system according to claim 16, further comprising a notification unit that notifies an outside party of information regarding a collision between the mobile device and the object.

20. 3. A moving device comprising the optical device according to claim 1 or 2, and capable of holding and moving the optical device.

21. 21. The moving device according to claim 20, further comprising a determination unit that determines a possibility of a collision with the object based on distance information of the object obtained by the optical device.

22. 22. The moving device according to claim 21, further comprising a control unit that outputs a control signal for controlling movement when it is determined that there is a possibility of a collision with the object.

23. 22. The mobile device according to claim 21, further comprising a warning unit that issues a warning to a user of the mobile device when it is determined that there is a possibility of a collision with the object.

24. The mobile device according to claim 21, further comprising a notification unit that notifies an outside source of information regarding the collision with the object.

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