Optical device, in-vehicle system and mobile device equipped therewith

Abstract

To provide a compact optical apparatus that can detect an object with high accuracy.SOLUTION: An optical apparatus 1 comprises: a first deflection portion 30 that deflects illumination light from a light source portion 10 to scan an object and deflects reflected light from the object; a first light guiding portion 20 that guides the illumination light from the light source portion 10 to the first deflection portion and guides the reflected light from the first deflection portion 30 to a light receiving portion 60; and a second light guiding portion 70 that guides the illumination light from the light source portion 10 to the light receiving portion 60. The first light guiding portion 20 includes a first passing region through which the illumination light from the light source portion 10 passes and a reflective region in which the reflected light from the first deflection portion 30 is reflected, and the second light guiding portion 70 guides, to the light receiving portion 60, light reflected in the reflective region without going through the object among the illumination light from the first deflection portion 30.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an optical device that detects an object by receiving reflected light from the illuminated object.

Background Art

[0002] As a distance measuring device for measuring the distance to an object, the object is scanned by deflecting illumination light from a light source by a deflector, and the distance to the object is calculated based on the time until the reflected light from the object is received or the phase of the reflected light. Such distance measuring devices are required to ensure distance measuring accuracy against changes in the environment such as temperature and humidity.

[0003] Patent Documents 1 and 2 describe a measuring device capable of correcting the distance to an object based on information obtained by guiding illumination light deflected by a deflector to a light receiving unit by an optical fiber before the illumination light is incident on the object.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the distance measuring devices according to Patent Documents 1 and 2, since the illumination light deflected by the deflector is directly incident on the optical fiber without passing through other members, the degree of freedom in arranging the incident surface of the optical fiber is low and it is difficult to miniaturize the entire device.

[0006] An object of the present invention is to provide an optical device that can detect an object with high accuracy while being small.

Means for Solving the Problems

[0007] An optical device as one aspect of the present invention for achieving the above objective includes: a first deflection unit that deflects illumination light from a light source to scan an object and deflects reflected light from the object; a first light guide unit that guides the illumination light from the light source to the first deflection unit and guides the reflected light from the first deflection unit to a light receiving unit; and a second light guide unit that guides the illumination light from the light source to the light receiving unit, wherein the first light guide unit includes a first passage region through which the illumination light from the light source passes and a reflection region through which the reflected light from the first deflection unit is reflected; and the second light guide unit processes the illumination light that has passed through the first passage region and been deflected by the first deflection unit, without passing through any other member, the light reflected in the reflection region. via the first light guide The light is guided to the light-receiving unit. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an optical device that can detect objects with high precision despite being small in size. [Brief explanation of the drawing]

[0009] [Figure 1] Schematic diagram of the main parts of the optical device according to Example 1 [Figure 2] Enlarged view of the main part of the optical device according to Example 1 [Figure 3] Schematic diagram of the main part of the first light guide according to Example 1 [Figure 4] Schematic diagram of the main part of the first light guide unit in a modified form. [Figure 5] Schematic diagram of the main parts of the optical device according to Example 2 [Figure 6] Schematic diagram of the main part of the first light guide according to Example 2 [Figure 7] Functional block diagram of the in-vehicle system according to the embodiment [Figure 8] Schematic diagram of a vehicle (mobile device) according to an embodiment. [Figure 9] Flowchart showing an example of operation of the in-vehicle system according to the embodiment. [Modes for carrying out the invention]

[0010] Preferred embodiments of the present invention will be described below with reference to the drawings. Note that the drawings may be drawn to a different scale than the actual dimensions for convenience. Furthermore, in each drawing, the same reference numeral is used for identical components, and redundant descriptions are omitted.

[0011] [Example 1] Figure 1 is a schematic diagram of the main parts of the optical device 1 according to Embodiment 1 of the present invention, as viewed from the side of an object not shown (-Z side). The optical device 1 comprises a light source unit 10, a first light guide unit 20 (branching unit), a first deflection unit 30, an optical system 40, a second deflection unit 50, a light receiving unit 60, a second light guide unit 70, and a control unit 80. However, the optical device 1 only needs to include the first light guide unit 20, the first deflection unit 30, and the second light guide unit 70, and the other components may be separate devices (units) that can be attached to the optical device 1 as needed. Figure 2 is an enlarged view of the main parts of the optical device 1, where Figure 2(a) shows the first optical path when light (illumination light) from the light source unit 10 is directed toward the object, and Figure 2(b) shows the second optical path when illumination light from the light source unit 10 is directed toward the second light guide unit 70 without passing through the object.

[0012] Optical device 1 can be used as a detection device (imaging device) that detects (images) an object by receiving light (reflected light) from the object, or as a distance measuring device that acquires the distance to the object (distance information). Optical device 1 according to this embodiment uses a technology called LiDAR (Light Detection And Ranging) which calculates the distance to the object based on the time it takes to receive reflected light from the object and the phase of that reflected light.

[0013] The light source unit 10 includes a light source 11 and an optical element 12. As the light source 11, a semiconductor laser or the like, which is a laser with high energy concentration and good directivity, can be used. As the semiconductor laser, for example, a vertical cavity surface emitting laser (VCSEL) may be used. When the optical device 1 is applied to an automobile or a traffic signal, etc., there is a possibility that a human is included in the object. Therefore, it is desirable to adopt a light source 11 that emits infrared light with little influence on the human eye. The wavelength of the illumination light emitted by the light source 11 according to this embodiment is 905 nm included in the near-infrared region.

[0014] The optical element 12 has a function of changing the convergence degree of the illumination light emitted from the light source 11. The optical element 12 according to this embodiment is a collimator lens (condensing element) that converts the divergent light emitted from the light source 11 into parallel light. However, the parallel light here includes not only strict parallel light but also substantially parallel light such as weak divergent light and weak convergent light. Note that the light source unit 10 may have a light shielding member (aperture) that determines the beam diameter (beam width) by restricting the illumination light from the optical element 12.

[0015] The first light guide unit 20 is a member (branching element) for branching the optical path (illumination optical path) when the illumination light from the light source unit 10 travels toward the object and the optical path (light receiving optical path) when the reflected light from the object travels toward the light receiving unit 60. That is, the first light guide unit 20 guides the illumination light from the light source unit 10 to the first deflection unit 30 and guides the reflected light from the first deflection unit 30 to the light receiving unit 60. FIG. 3 is a schematic diagram of the main part of the first light guide unit 20 according to this embodiment. FIG. 3(a) shows a view when the first surface 201 on the side of the light source unit 10 and the second surface 202 on the side of the first deflection unit 30 of the first light guide unit 20 are viewed from the normal direction, and a cross-sectional view (XY cross-section) at a position including the first passing region 203 of the first light guide unit 20. FIG. 3(b) shows a view when the optical path shown in FIG. 2(b) is viewed from the -X side.

[0016] As shown in Fig. 3(a), the first light guide part 20 includes a first passage region 203 through which the illumination light from the light source part 10 passes, a reflection region 204 where the reflected light from the first deflection part 30 is reflected, and a second passage region 205 through which the light from the second light guide part 70 passes. The first passage region 203 and the second passage region 205 according to this embodiment are holes (openings) provided in the first light guide part 20 and penetrate from the first surface 201 to the second surface 202. The reflection region 204 is a reflection film (reflection layer) composed of a metal, a dielectric, etc., provided in a region of the second surface 202 other than the first passage region 203 and the second passage region 205. That is, the first light guide part 20 according to this embodiment is composed of a perforated mirror as a single reflection member.

[0017] Note that the first passage region 203 and the second passage region 205 according to this embodiment are hollow holes, but a light-transmitting member may be provided at the position of the hollow holes as required. In that case, for example, the first light guide part 20 can be manufactured by providing a reflection film as the reflection region 204 in a portion other than the portions corresponding to the first passage region 203 and the second passage region 205 in the light-transmitting member. Also, as the first light guide part 20, not only a perforated mirror but also a beam splitter, a prism, a half mirror, etc. may be used. Further, the first light guide part 20 may be composed of a plurality of optical members.

[0018] In this embodiment, the first light guide unit 20 is arranged such that the first surface 201 and the second surface 202 are nonparallel to both the optical axis direction (X direction) of the light source unit 10 and the optical axis direction (Y direction) of the light receiving unit 60, in order to branch the illumination light path and the light receiving light path. Therefore, as shown in Figure 3(a), the inner surface of the first passing region 203 is non-perpendicular to the first surface 201 and the second surface 202 (nonparallel to their respective normals). Thus, the positions of the first passing region 203 on the first surface 201 and the second surface 202 are different in the plane of Figure 3(a) (directions perpendicular to the normals of each surface). The same applies to the second passing region 205. Furthermore, it is desirable that areas other than the first passing region 203 and the second passing region 205 on the first surface 201 be provided with a light-shielding film (absorbing film) to block (absorb) light in order to suppress the light reflected there from reaching the light-receiving section 60.

[0019] As described above, the optical device 1 according to this embodiment includes a first light guide unit 20, thereby configuring a coaxial system in which a portion of the illumination light path from the light source unit 10 to the first deflection unit 30 and a portion of the reflected light path from the first deflection unit 30 to the light receiving unit 60 coincide with each other. This makes it possible to reduce the number of parts and miniaturize the entire device compared to a non-coaxial system in which the illumination light path and the reflected light path do not coincide with each other.

[0020] The first deflection unit 30 (first scanning unit) is a member (deflection element) that deflects illumination light from the first light guide unit 20 to scan an object and deflects reflected light from the object to guide it to the first light guide unit 20. The first deflection unit 30 according to this embodiment is composed of a single drive mirror (movable mirror). Specifically, the first deflection unit 30 is a rotating polyhedron mirror (polygon mirror) having four deflection surfaces (reflection surfaces) and rotatable about a first rotation axis parallel to the Z direction. With the first deflection unit 30, the object can be scanned in the X direction by deflecting the illumination light with each rotating deflection surface. The number of deflection surfaces of the first deflection unit 30 may be three or fewer, or five or more, as needed.

[0021] In this embodiment, the first deflection unit 30 is positioned such that its first rotation axis is non-parallel to the optical axis (dotted line) of the light source unit 10 shown in Figure 1. This configuration allows for a smaller size of each deflection surface compared to the case where the first rotation axis is parallel to (coincides with) the optical axis of the light source unit 10, as in the device described in Patent Document 1. When the first rotation axis is parallel to the optical axis of the light source unit 10, it becomes necessary to tilt each deflection surface of the first deflection unit 30 with respect to the optical axis (main ray of illumination light) of the light source unit 10 in the cross-section including the first rotation axis, making it difficult to miniaturize each deflection surface. In particular, if a polygon mirror or other device with a large number of deflection surfaces is used as the first deflection unit 30, the weight of the first deflection unit 30 increases with the size of each deflection surface, thus increasing the load on the drive unit (not shown) for rotating the first deflection unit 30. Therefore, it is desirable to make the first rotation axis and the optical axis of the light source unit 10 non-parallel, as in this embodiment.

[0022] The optical system 40 is a component that guides illumination light from the first deflection unit 30 to the object and guides reflected light from the object to the first deflection unit 30. The optical system 40 according to this embodiment is composed of a plurality of lenses having refractive power, and is an optical system (afocal system) that does not have refractive power as a whole. Specifically, the optical system 40 is a telescope that enlarges the diameter of illumination light from the first deflection unit 30 and reduces the diameter of reflected light from the object. The optical system 40 according to this embodiment is composed of a first lens 41 with positive power and a second lens 42 with positive power, which are arranged in order from the side of the first deflection unit 30. However, the configuration of the optical system 40 is not limited to this, and may be composed of one or three or more lenses as needed.

[0023] In this embodiment, the absolute value of the optical magnification (lateral magnification) β of the optical system 40 is greater than 1 (|β|>1). As a result, the deflection angle of the principal ray of the illumination light emitted from the optical system 40 is smaller than the deflection angle of the principal ray of the illumination light that is deflected by the first deflection unit 30 and incident on the optical system 40, thereby improving the resolution when detecting an object. The illumination light from the light source unit 10 is deflected by the first deflection unit 30 via the first light guide unit 20, magnified by the optical system 40 according to the optical magnification β, and illuminates the object via the second deflection unit 50, which will be described later. The reflected light from the object is then reduced by the optical system 40 according to the optical magnification 1 / β, deflected by the first deflection unit 30, and reaches the light receiving unit 60.

[0024] In this way, by positioning the optical system 40 on the object side of the first deflection unit 30, the diameter of the illumination light can be increased, allowing a sufficiently wide area to be illuminated even if the divergence angle of the illumination light is reduced. This ensures sufficient illuminance and resolution even when the object is far away. Furthermore, by increasing the pupil diameter with the optical system 40, more reflected light from the object can be captured, improving the distance and accuracy of the measurement. Note that the optical system 40 does not have to be a telescope that increases the diameter of the illumination light, and may be an optical system that decreases the diameter of the illumination light as needed. Also, the optical system 40 does not have to be an afocal system, and may be an optical system that has refractive power throughout the entire system as needed. In addition, the optical system 40 may be removed as needed, such as when the object is close.

[0025] The second deflection unit 50 (second scanning unit) is a component that deflects illumination light from the first deflection unit 30 to scan an object, and also deflects reflected light from the object to guide it to the first deflection unit 30. In this embodiment, the second deflection unit 50 is composed of a single drive mirror (movable mirror). Specifically, the second deflection unit 50 is a oscillating mirror (galvanometer mirror) having one deflection surface (reflection surface) and capable of rotating (oscillating) about a second rotation axis (oscillating axis) parallel to the X direction. With the second deflection unit 50, the object can be scanned in the Y direction by deflecting the illumination light with the rotating deflection surface.

[0026] The optical device 1 according to this embodiment can scan an object in two directions, the X and Y directions, which are perpendicular to each other, using two deflection units, a first deflection unit 30 and a second deflection unit 50. This makes it possible to widen the scanning range (scanning angle) compared to a configuration in which the object can only be scanned in one direction. Alternatively, the first deflection unit 30 and the second deflection unit 50 may be made common by employing a single deflection unit capable of two-dimensional scanning of the object, such as a mirror that can rotate around two axes (two-axis driven mirror). For example, a MEMS (Micro Electro Mechanical System) mirror can be used as the two-axis driven mirror.

[0027] The types of the first deflection section 30 and the second deflection section 50, and the number of deflection surfaces of each, are not limited to those described above and can be set as appropriate. For example, the first deflection section 30 may be a galvanometer mirror similar to that of the second deflection section 50, or the second deflection section 50 may be a polygon mirror similar to that of the first deflection section 30, or each of the deflection sections may be a MEMS mirror. Furthermore, each deflection section is not limited to being able to rotate 360°, and the rotation angle (oscillation angle) may be limited as needed.

[0028] The light-receiving unit 60 includes an optical filter 61, an optical element 62, and a light-receiving element 63 (photoelectric conversion element). The optical filter 61 is a component that allows only desired light to pass through and blocks (absorbs) other unwanted light. The optical filter 61 in this embodiment is a bandpass filter that transmits only light in the wavelength band corresponding to the illumination light emitted from the light source 11. The optical element 62 is a focusing lens that focuses the light that has passed through the optical filter 61 onto the light-receiving surface of the light-receiving element 63. Note that the configuration of the optical filter 61 and the optical element 62 is not limited to this embodiment. For example, the order of arrangement of each component may be changed or multiple units of each component may be arranged as needed. The light-receiving element 63 is a component (sensor) that receives light from the optical element 62, converts it photoelectrically, and outputs a signal. As the light-receiving element 63, a PD (Photo Diode), APD (Avalanche Photo Diode), SPAD (Single Photon Avalanche Diode), etc. can be used.

[0029] The second light guide 70 is a component for guiding illumination light from the light source 10 to the light receiving unit 60. As shown in Figure 2(b), the second light guide 70 is positioned to receive illumination light from the first deflection unit 30 that does not pass through an object. That is, the incident surface 71 of the second light guide 70 is positioned so that the illumination light deflected by the first deflection unit 30 passes through when the deflection angle of the first deflection unit 30 does not scan an object. Since the light from the second light guide 70 to the light receiving unit 60 does not pass through an object, the output (reference signal) of the light receiving unit 60 corresponding to the light from the second light guide 70 does not change depending on the type of object or the distance to the object. Therefore, by using this reference signal, it is possible to correct the distance information of the object and to detect abnormalities in the optical device 1.

[0030] Furthermore, the second light guide unit 70 in this embodiment is arranged to guide the illumination light from the first deflection unit 30 that has been reflected by the reflection region 204 of the first light guide unit 20 without passing through an object to the light receiving unit 60. That is, the incident surface 71 of the second light guide unit 70 is positioned so that the illumination light deflected by both the first deflection unit 30 and the reflection region 204 passes through when the deflection angle of the deflection surface of the first deflection unit 30 is such that it does not scan an object. As a result, the incident surface 71 of the second light guide unit 70 can be positioned in the space between the first light guide unit 20 or the light receiving unit 60 and the first deflection unit 3 in a direction parallel to the optical axis of the light source unit 10 (X direction), thereby enabling miniaturization of the entire device.

[0031] If we were to attempt to direct the illumination light from the first deflection unit 30 that does not enter the reflection region 204 into the second light guide unit 70, it would be necessary to place an incident surface 71 between the first light guide unit 20 and the light receiving unit 60, or between the first light guide unit 20 and the optical system 40. In this case, as shown in Figures 1 and 2, the respective spaces are narrow, so in order to place the incident surface 71 there, it would be necessary to move each component far apart from each other, making it difficult to miniaturize the entire device. On the other hand, the space between the first light guide unit 20 or the light receiving unit 60 and the first deflection unit 3 is relatively wide, so it is possible to place the incident surface 71 while suppressing an increase in the overall size of the device.

[0032] The second light guide 70 in this embodiment is an optical fiber set to a predetermined length. By using an optical fiber as the second light guide 70, it is possible to secure a predetermined optical path length while making it easy to handle the optical path, thereby preventing interference between the optical path and other components and suppressing an increase in the overall size of the device. However, the second light guide 70 may be composed of optical elements such as a reflective element (mirror) or a refractive element (lens, prism) as needed. In this case, it is sufficient to configure the optical elements so that their positions do not change, that is, so that the optical path in the second light guide 70 does not change.

[0033] As shown in Figure 2(b), light from the second light guide 70 enters the light receiving unit 60 via the first light guide 20. That is, the exit surface 72 of the second light guide 70 is positioned so that the light emitted from it goes towards the light receiving unit 60 via the first light guide 20. With this configuration, the routing of the optical path becomes easier compared to a configuration in which light from the exit surface 72 enters the light receiving unit 60 without passing through the first light guide 20, thus enabling miniaturization of the entire device. In this embodiment, in order to configure the light from the exit surface 72 to pass through the first light guide 20 and go towards the light receiving unit 60, the exit surface 72 is positioned on the side opposite to the light receiving unit 60 relative to the first light guide 20, facing the first surface 201.

[0034] Furthermore, as shown in Figure 3(b), in this embodiment, the emission surface 72 is positioned so that light from the second light guide 70 passes through the second passing region 205 of the first light guide 20 and heads toward the light receiving section 60. This suppresses the generation of unwanted light from the second light guide 70 that is reflected by the inner surface of the holding part (lens barrel) that holds each component of the light receiving section 60 and incident on the light receiving element 63, thereby suppressing the generation of noise in the output of the light receiving element 63. In particular, since light emitted from an optical fiber generally has a large divergence angle, this effect is especially pronounced when an optical fiber is used as the second light guide 70. Therefore, it is desirable that the size of the second passing region 205 be set so as to block such unwanted light. However, if necessary, the emission surface 72 may be positioned so that light from the second light guide 70 passes through the first passing region 203 of the first light guide 20 and heads toward the light receiving section 60.

[0035] Here, an optical device relating to a modification of Example 1 will be described. Figure 4 is a schematic diagram of the main part of the first light guide unit 21 relating to this modification. The optical device relating to this modification is the same as the optical device 1 relating to Example 1, except for the configuration of the first light guide unit 21 and the arrangement of the second light guide unit 70. Figure 4(a) shows the first surface 211 on the light source unit 10 side and the second surface 212 on the first deflection unit 30 side of the first light guide unit 21 as viewed from the normal direction, and a cross-sectional view (XY cross-section) of the first light guide unit 21 at a position including the first passage region 213. Figure 4(b) shows the optical path shown in Figure 2(b) as viewed from the -X side.

[0036] The first light guide 21 in this modified example includes a first surface 211 and a second surface 212, and a first passage region 213 and a reflection region 214 provided thereon, similar to the first light guide 20 in Example 1. On the other hand, the first light guide 21 does not have an opening corresponding to the second passage region 205 of the first light guide 20 in Example 1. As shown in Figure 4(b), in this modified example, the exit surface 72 is arranged so that light from the second light guide 70 passes through the first passage region 213 of the first light guide 21 and is incident on the light receiving section 60. According to this modified example, it is not necessary to provide a second passage region 205 in the first light guide 21, so the size and manufacturing cost of the first light guide 21 can be reduced compared to Example 1.

[0037] As described above, in Example 1 and its modified form, light from the second light guide 70 is incident on the light-receiving element 63 via the optical element 62. With this configuration, the output surface 72 of the second light guide 70 can be positioned to face the light-receiving element 63 directly, and light can be incident on the light-receiving surface of the light-receiving element 63 from a direction substantially perpendicular to it. Therefore, compared to a configuration in which light from the second light guide 70 is incident on the light-receiving element 63 without going through the optical element 62, that is, a configuration in which light from the output surface 72 is obliquely incident on the light-receiving element 63, it is possible to suppress an increase in the overall size of the device and a decrease in the accuracy of light detection by the light-receiving element 63.

[0038] As shown in Figures 1 and 2(a), in the first optical path of this embodiment, illumination light from the light source 10 passes through the first passing region 203 from the side of the first surface 201 of the first light guide 20 and is incident on the deflection surface of the first deflection section 30. The illumination light deflected by the first deflection section 30 is deflected by the second deflection section 50 via the optical system 40 and directed toward an object (not shown). The reflected light from the object then passes sequentially through the second deflection section 50, the optical system 40, and the first deflection section 30 and is incident on the second surface 202 of the first light guide 20, reflected by the reflection region 204, and incident on the light receiving section 60.

[0039] As shown in Figures 2(b) and 3(b), in the second optical path of this embodiment, illumination light from the light source 10 passes through the first passing region 203 from the side of the first surface 201 of the first light guide 20 and is incident on the deflection surface of the first deflection section 30. The illumination light deflected by the first deflection section 30 is incident on the second surface 202 of the first light guide 20 in the scanning field of view that does not enter the optical system 40, is reflected by the reflection region 204 and is incident on the incident surface 71 of the second light guide 70. The illumination light from the incident surface 71 of the second light guide 70 propagates inside the second light guide 70 and is emitted from the exit surface 71 of the second light guide 70, and is incident on the light receiving section 60 via the first passing region 203 of the first light guide 20.

[0040] Here, the deflection surface of the first deflection unit 30 in this embodiment is positioned at the entrance pupil of the optical system 40. The deflection surface of the second deflection unit 50 in this embodiment is positioned at the exit pupil of the optical system 40. This makes it possible to reduce the deflection surface of each deflection unit, thereby enabling miniaturization of the entire device and reduction of the load on the drive unit (not shown) for driving each deflection unit. However, the position of the deflection surface of each deflection unit may be offset from the pupil position of the optical system 40 as needed.

[0041] The control unit 80 controls the light source 11, the first deflection unit 30, the second deflection unit 50, and the light receiving element 63, etc. The control unit 80 is, for example, a processing unit (processor) such as a CPU (Central Processing Unit), or a computing unit (computer) equipped with one. The control unit 80 drives the light source 11, the first deflection unit 30, and the second deflection unit 50, respectively, with a predetermined drive voltage and a predetermined drive frequency. The control unit 80 can also, for example, control the light source 11 to make the illumination light pulsed light, or generate signal light by modulating the intensity of the illumination light.

[0042] Furthermore, the control unit 80 can acquire distance information of an object based on the time from the time when illumination light is emitted from the light source 11 (light emission time) to the time when the light receiving element 63 receives reflected light from the object (light reception time). In this case, the control unit 80 may acquire the signal from the light receiving element 63 at a specific frequency. Alternatively, distance information may be acquired based on the phase of the reflected light from the object, rather than the time until the reflected light from the object is received. Specifically, the difference (phase difference) between the phase of the signal from the light source 11 and the phase of the signal output from the light receiving element 63 may be calculated, and the distance information of the object may be acquired by multiplying this phase difference by the speed of light.

[0043] Furthermore, the control unit 80 acquires the output (reference signal) of the photodetector 63 corresponding to the illumination light that has passed through the second light guide unit 70, which has a fixed optical path length. The control unit 80 can correct the distance information acquired based on the output of the photodetector 63 corresponding to the reflected light from the object, based on the reference signal. This ensures the measurement accuracy of the optical device 1. In addition, the control unit 80 can detect an abnormality in the optical device 1 based on the output of the photodetector 63 when the light detector 60 is not receiving reflected light from the object. When an abnormality is detected, the control unit 80 can temporarily suspend the operation of the optical device 1 or notify the user, thereby ensuring the reliability of the optical device 1.

[0044] For example, in the optical path passing through the second light guide 70 shown in Figure 2(b), there may be cases where the light receiving element 63 does not receive illumination light even though the light source 11 is emitting light, or where the amount of illumination light received by the light receiving element 63 is significantly low. In this case, there is a possibility that an abnormality (malfunction) has occurred in at least one of the light source 11, the light receiving element 63, and the first deflection unit 3. Such an abnormality can be detected by the output (signal) of the light receiving element 63 when it is not receiving reflected light from the object, that is, when the deflection angle of the deflection surface of the first deflection unit 30 is the angle at which the illumination light is deflected toward the second light guide 70.

[0045] When the optical device 1 according to this embodiment is used as a distance measuring device, the optical device 1 is suitable for in-vehicle systems installed in, for example, automobiles (vehicles) or fixed-point monitoring systems installed in traffic signals. In in-vehicle systems and fixed-point monitoring systems, the objects (targets) that the optical device 1 measures distance from are, for example, pedestrians, obstacles, vehicles, etc., and are expected to be about 1 to 300 m away from the optical device 1. The optical device 1 according to this embodiment can detect objects in such a range from short to long distances with good accuracy. Furthermore, in-vehicle systems and fixed-point monitoring systems can perform vehicle control, obstacle detection, etc., based on the distance information of objects acquired by the optical device 1.

[0046] [Example 2] Figure 5 is a schematic diagram of the main parts of the optical device 2 according to Embodiment 2 of the present invention in a cross-section (XZ section) including the optical axis. Figure 5(a) shows the first optical path when the illumination light from the light source 10 is directed toward the object, and Figure 5(b) shows the second optical path when the illumination light from the light source 10 is directed toward the second light guide 70 without passing through the object. In the optical device 2 according to this embodiment, the same configuration as the optical device 1 according to Embodiment 1 described above will not be explained.

[0047] The optical device 2 according to this embodiment comprises a light source unit 10, a first light guide unit 22, a first deflection unit 31, an optical system 40, a light receiving unit 60, a second light guide unit 70, and a control unit (not shown). However, the optical device 2 only needs to include at least the first light guide unit 22, the first deflection unit 31, and the second light guide unit 70, and the other components may be separate devices (units) that can be attached to the optical device 1 as needed. The control unit according to this embodiment is omitted in Figure 5, but it has the same functions as the control unit 80 according to Embodiment 1.

[0048] Figure 6 is a schematic diagram of the main parts of the first light guide unit 22 according to this embodiment. Figure 6(a) shows the first surface 221 on the light source unit 10 side and the second surface 222 on the first deflection unit 31 side of the first light guide unit 22 as viewed from the normal direction, and a cross-sectional view (XY section) of the first light guide unit 22 at a position including the first passage region 223. Figure 6(b) shows the optical path shown in Figure 5(b) as viewed from a direction perpendicular to the optical axis of the light receiving unit 60. The first light guide unit 22 includes a first passage region 223 through which illumination light from the light source unit 10 passes, and a reflection region 224 through which reflected light from the first deflection unit 31 is reflected.

[0049] The first deflection unit 31 in this embodiment is a mirror rotatable around two axes (two-axis driven mirror). Specifically, the first deflection unit 31 is a MEMS mirror having a first rotation axis (first oscillation axis) parallel to the Z direction and a second rotation axis (second oscillation axis) parallel to the deflection plane of the first deflection unit 31 and included in the XY cross-section. The first deflection unit 31 allows scanning of an object in two directions perpendicular to each other, the Y direction and the Z direction. Thus, unlike the optical device 1 in Embodiment 1, the optical device 2 in this embodiment has only a single first deflection unit 31 as the deflection unit. As a result, the number of parts can be reduced and the overall size of the device can be reduced compared to the optical device 1.

[0050] As shown in Figure 5(b), the second light guide unit 70 is positioned to guide the illumination light from the first deflection unit 31, which has been reflected by the reflection region 224 of the first light guide unit 22 without passing through an object, to the light receiving unit 60. That is, the incident surface 71 of the second light guide unit 70 is positioned so that the illumination light deflected by both the first deflection unit 31 and the reflection region 224 passes through when the deflection angle of the first deflection unit 31 is such that it does not scan an object. As a result, the illumination light can be guided to the second light guide unit 70 using the space between the first light guide unit 22 or the light receiving unit 60 and the first deflection unit 31 in a direction parallel to the optical axis of the light source unit 10 (Y direction), making it possible to miniaturize the entire device.

[0051] Furthermore, as shown in Figure 5(b), light from the second light guide 70 is incident on the light receiving unit 60 via the first light guide 22. That is, the exit surface 72 of the second light guide 70 is positioned so that the light emitted from it is directed towards the light receiving unit 60 via the first light guide 22. With this configuration, the routing of the optical path becomes easier compared to a configuration in which light from the exit surface 72 is incident on the light receiving unit 60 without passing through the first light guide 22, thus enabling miniaturization of the entire device. In this embodiment, the exit surface 72 is positioned between the first deflection unit 31 and the optical system 40 in the optical axis direction (X direction) of the optical system 40. In addition, in order to configure the light from the exit surface 72 to pass through the first light guide 22 and be directed towards the light receiving unit 60, the exit surface 72 is positioned so as to face the second surface 222 on the side opposite to the light receiving unit 60 relative to the first light guide 22.

[0052] Furthermore, the emission surface 72 in this embodiment is arranged such that the light emitted from there is reflected by the reflection region 224 of the first light guide 22 and directed toward the light receiving section 60. By adopting this configuration in which the light emitted from the second light guide 70 is guided toward the light receiving section 60 by the reflection region 224, it becomes unnecessary to provide a second passage region in the first light guide 22 that is different from the first passage region 223. Therefore, in the optical device 2 according to this embodiment, the size and manufacturing cost of the first light guide 22 can be reduced compared to Embodiment 1.

[0053] In this embodiment, the incident surface 71 of the second light guide unit 70 is positioned in the XY cross-section shown in Figure 5(b) to which illumination light passes when the first deflection unit 31 is at a deflection angle that does not scan the object. That is, the incident surface 71 is positioned at a scanning angle outside the scanning range of the object when the first deflection unit 31 rotates about the first rotation axis. However, if necessary, the incident surface 71 may be positioned at a scanning angle outside the scanning range of the object when the first deflection unit 31 rotates about the second rotation axis.

[0054] [In-vehicle systems] Figure 7 is a diagram illustrating the configuration of the optical device 1 and the in-vehicle system (driving assistance device) 1000 equipped therewith according to this embodiment. The in-vehicle system 1000 is held by a movable mobile body (mobile device) such as an automobile (vehicle) and is a device for assisting the driving (operation) of the vehicle based on distance information of objects such as obstacles and pedestrians around the vehicle acquired by the optical device 1. Figure 8 is a schematic diagram of a vehicle 500 including the in-vehicle system 1000. In Figure 8, the distance measurement range (detection range) of the optical device 1 is shown set to the front of the vehicle 500, but the distance measurement range may also be set to the rear or side of the vehicle 500.

[0055] As shown in Figure 7, the in-vehicle system 1000 comprises an optical device 1, a vehicle information acquisition device 200, a control device (ECU: electronic control unit) 300, and a warning device (warning unit) 400. In the in-vehicle system 1000, the control unit 80 provided in the optical device 1 has the functions of a distance acquisition unit (acquisition unit) and a collision determination unit (determination unit). However, if necessary, the in-vehicle system 1000 may provide a distance acquisition unit and a collision determination unit separate from the control unit 80, and each may be provided outside the optical device 1 (for example, inside the vehicle 500). Alternatively, the control device 300 may be used as the control unit 80.

[0056] Figure 9 is a flowchart showing an example of the operation of the in-vehicle system 1000 according to this embodiment. The operation of the in-vehicle system 1000 will be described below in accordance with this flowchart.

[0057] First, in step S1, the light source unit 10 of the optical device 1 illuminates the object around the vehicle, and the light receiving unit 60 receives reflected light from the object. Based on the signal output by the light receiving unit 60, the control unit 80 acquires distance information of the object. In step S2, the vehicle information acquisition device 200 acquires vehicle information, including the vehicle speed, yaw rate, and steering angle. Then, in step S3, the control unit 80 uses the distance information acquired in step S1 and the vehicle information acquired in step S2 to determine whether the distance to the object falls within a preset distance range.

[0058] This allows the system to determine whether or not an object exists within a set distance around the vehicle and to determine the possibility of a collision between the vehicle and the object. Steps S1 and S2 may be performed in the reverse order of the above, or they may be processed in parallel. The control unit 80 determines "possibility of collision" if an object exists within the set distance (step S4), and determines "no possibility of collision" if an object does not exist within the set distance (step S5).

[0059] Next, if the control unit 80 determines that there is a possibility of collision, it notifies (transmits) the determination result to the control device 300 and the warning device 400. At this time, the control device 300 controls the vehicle based on the determination result from the control unit 80 (step S6), and the warning device 400 issues a warning to the vehicle user (driver) based on the determination result from the control unit 80 (step S7). Note that notification of the determination result only needs to be made to at least one of the control device 300 and the warning device 400.

[0060] The control device 300 controls the vehicle, for example, by generating control signals to apply the brakes, release the accelerator, turn the steering wheel, and suppress the output of the engine or motor by generating braking force on each wheel. The warning device 400 also provides warnings to the driver, for example, by emitting a warning sound, displaying warning information on a screen such as a car navigation system, or vibrating the seat belt or steering wheel.

[0061] As described above, the in-vehicle system 1000 according to this embodiment can detect objects and measure their distance through the above-described process, making it possible to avoid collisions between the vehicle and the objects. In particular, by applying the optical device 1 according to each of the embodiments described above to the in-vehicle system 1000, high distance measurement accuracy can be achieved, making it possible to detect objects and determine collisions with high accuracy.

[0062] In this embodiment, the in-vehicle system 1000 is applied to driver assistance (collision damage mitigation), but it is not limited to this, and the in-vehicle system 1000 may also be applied to cruise control (including with full-speed following function) or autonomous driving. Furthermore, the in-vehicle system 1000 is not limited to automobiles and other vehicles, but can be applied to mobile objects such as ships, aircraft, and industrial robots. Moreover, it is not limited to mobile objects, but can be applied to various devices that utilize object recognition, such as intelligent transportation systems (ITS) and surveillance systems.

[0063] Furthermore, the in-vehicle system 1000 and the mobile device 500 may be equipped with a notification device (notification unit) to notify the manufacturer of the in-vehicle system or the dealer of the mobile device if the mobile device 500 collides with an obstacle. For example, the notification device may be one that sends information regarding the collision between the mobile device 500 and an obstacle (collision information) to a pre-set external notification destination via email or the like.

[0064] In this way, by adopting a configuration in which collision information is automatically notified by the notification device, it is possible to promptly take action such as inspection and repair after a collision occurs. The recipients of the collision information may be insurance companies, medical institutions, the police, or any other recipients set by the user. Furthermore, the notification device may be configured to notify recipients not only of collision information, but also of malfunction information of various parts and information on the wear of consumables. The detection of whether or not a collision has occurred may be performed using distance information acquired based on the output from the light receiving unit 60 described above, or it may be performed by other detection units (sensors).

[0065] [Differentiation] Although preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and various combinations, modifications, and changes are possible within the scope of its gist.

[0066] For example, other optical elements may be placed in the optical path between the first light guide and the first deflection unit as needed. However, considering the possibility that light reflected from the optical surface of such optical elements may enter the light receiving unit as unwanted light, it is desirable that nothing is placed in the optical path between the first light guide and the first deflection unit, as in the embodiments described above. In other words, it is desirable to adopt a configuration in which illumination light from the region through which the first light guide passes enters the first deflection unit without passing through other surfaces.

[0067] In each embodiment, a parallel plate is used as the base material for the first light guide, and the first and second surfaces of the first light guide are parallel to each other. However, the first and second surfaces may be non-parallel if necessary. Also, at least one of the first and second surfaces may be curved if necessary. However, in order to facilitate the manufacture of the first light guide, it is desirable to make the first and second surfaces flat and to reduce the angle between them.

[0068] In each embodiment, each component is integrally held by a holding member (housing) not shown, but each component may be configured as a separate part if necessary. For example, the first light guide and the first deflection part may be detachable from each other. In that case, the holding member that holds each component should be provided with a connecting part (joint part) for connecting them to each other. [Explanation of symbols]

[0069] 1 Optical device 10 Light source section 20 First light guide 30 First deflection section 40 Optical system 60 Light receiving part 70 Second light guide

Claims

1. A first deflection unit that deflects the illumination light from the light source to scan an object, and also deflects the reflected light from the object, A first light guide unit that guides the illumination light from the light source unit to the first deflection unit and the reflected light from the first deflection unit to the light receiving unit, The system includes a second light guide that guides the illumination light from the light source to the light receiving unit, The first light guide includes a first passage region through which the illumination light from the light source passes, and a reflection region through which the reflected light from the first deflection region is reflected. The optical device is characterized in that the second light guide unit guides the light reflected in the reflection region, which has passed through the first passing region and been deflected by the first deflection unit, to the light receiving unit via the first light guide unit without passing through any other member.

2. The optical apparatus according to claim 1, characterized in that the first deflection unit is rotatable about a first rotation axis, and the first rotation axis is non-parallel to the optical axis of the light source unit.

3. The optical apparatus according to claim 1 or 2, characterized by comprising an optical system that guides the illumination light from the first deflection unit to the object and guides the reflected light from the object to the first deflection unit.

4. The optical apparatus according to claim 3, characterized in that the optical system increases the diameter of the illumination light from the first deflection unit and decreases the diameter of the reflected light from the object.

5. The optical apparatus according to claim 3 or 4, characterized in that the deflection surface of the first deflection portion is positioned at the entrance pupil of the optical system.

6. The optical apparatus according to claim 1 or 2, characterized in that it comprises a second deflection unit that deflects the illumination light from the first deflection unit to scan the object and deflects the reflected light from the object to guide it to the first deflection unit.

7. The optical apparatus according to claim 6, characterized by comprising an optical system that guides the illumination light from the first deflection unit to the second deflection unit and the reflected light from the second deflection unit to the first deflection unit.

8. The optical device according to claim 7, characterized in that the deflection surface of the second deflection portion is positioned at the location of the exit pupil of the optical system.

9. The optical apparatus according to any one of claims 1 to 8, characterized in that the incident surface of the second light guide is arranged between the first light guide and the first deflection part in a direction parallel to the optical axis of the light source.

10. The optical apparatus according to any one of claims 1 to 9, characterized in that the emission surface of the second light guide is arranged on the side opposite to the light receiving section with respect to the first light guide.

11. A first deflection unit that deflects illumination light from a light source to scan an object and deflects reflected light from the object, A first light guide unit that guides the illumination light from the light source unit to the first deflection unit and the reflected light from the first deflection unit to the light receiving unit, The system includes a second light guide that guides the illumination light from the light source to the light receiving unit, The emission surface of the second light guide is positioned on the side opposite to the light receiving section relative to the first light guide, The first light guide includes a first passage region through which the illumination light from the light source passes, and a reflection region through which the reflected light from the first deflection region is reflected. The optical device is characterized in that the second light guide unit guides the light reflected in the reflection unit to the light receiving unit from the illumination light that has passed through the first passing unit and been deflected by the first deflection unit, without passing through any other member.

12. The optical apparatus according to any one of claims 1 to 11, characterized in that the first light guide portion includes a second passage region through which light from the second light guide portion passes.

13. A first deflection unit that deflects illumination light from a light source to scan an object and deflects reflected light from the object, A first light guide unit that guides the illumination light from the light source unit to the first deflection unit and the reflected light from the first deflection unit to the light receiving unit, The system includes a second light guide that guides the illumination light from the light source to the light receiving unit, The first light guide unit includes a first passage region through which the illumination light from the light source unit passes, a reflection region through which the reflected light from the first deflection unit is reflected, and a second passage region through which light from the second light guide unit passes. The optical device is characterized in that the second light guide unit guides the light reflected in the reflection unit to the light receiving unit from the illumination light that has passed through the first passing unit and been deflected by the first deflection unit, without passing through any other member.

14. The optical apparatus according to any one of claims 1 to 12, characterized in that the reflected light from the object does not enter the second light guide portion.

15. A first deflection unit that deflects illumination light from a light source to scan an object and deflects reflected light from the object, A first light guide unit that guides the illumination light from the light source unit to the first deflection unit and the reflected light from the first deflection unit to the light receiving unit, The system includes a second light guide that guides the illumination light from the light source to the light receiving unit, The first light guide includes a first passage region through which the illumination light from the light source passes, and a reflection region through which the reflected light from the first deflection region is reflected. The second light guide does not receive reflected light from the object. The optical device is characterized in that the second light guide unit guides the light reflected in the reflection unit to the light receiving unit from the illumination light that has passed through the first passing unit and been deflected by the first deflection unit, without passing through any other member.

16. The optical apparatus according to any one of claims 1 to 15, further comprising a third light guide that guides the reflected light from the object reflected by the reflective region to the light receiving unit.

17. The optical apparatus according to any one of claims 1 to 16, characterized in that the second light guide is an optical fiber.

18. The optical apparatus according to any one of claims 1 to 17, wherein the light-receiving unit has an optical element and a light-receiving element that receives light from the optical element, and the light from the second light-guide unit is incident on the light-receiving element via the optical element.

19. The optical apparatus according to any one of claims 1 to 18, further comprising a control unit that acquires distance information of an object based on the output of the light receiving unit corresponding to the reflected light from the object.

20. The optical apparatus according to claim 19, characterized in that the control unit corrects the distance information based on the output of the light receiving unit corresponding to the light from the second light guide unit.

21. The optical apparatus according to claim 19 or 20, characterized in that the control unit detects an abnormality in the optical apparatus based on the output of the light receiving unit when the light receiving unit does not receive the reflected light.

22. An in-vehicle system comprising an optical device according to any one of claims 1 to 21, characterized in that it determines the possibility of a collision between the vehicle and the object based on distance information of the object obtained by the optical device.

23. A mobile device comprising an optical device according to any one of claims 1 to 21, characterized in that it is capable of holding and moving the optical device.

24. The moving device according to claim 23, characterized in that it determines the possibility of collision with the object based on distance information of the object obtained by the optical device.

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