Patent Application
20220113535
The present invention relates to an optical apparatus that receives light reflected on an illuminated object to detect the object.
A distance measuring device to measure a distance to an object has been known in which the object is scanned by deflecting the illumination light from a light source by a deflection device so that the distance to the object is calculated based on a time until receiving the reflected light from the object or on a phase of the reflected light.
U.S. Patent Application Publication No. 2009/0201486 discloses a distance measuring device in which diameters of an illumination light and a reflected light can be changed by a telescope disposed in the object side of a deflecting unit.
In addition, Japanese Patent Application Laid-Open No. 2016-102738 discloses a distance measuring device in which a deflection angle of an illumination light from a deflecting unit can be changed by a magnification-varying lens disposed in an object side of the deflecting unit.
However, in the distance measuring device disclosed in U.S. Patent Application Publication No. 2009/0201486 and Japanese Patent Application Laid-Open No. 2016-102738, illumination light is reflected on each of lens surfaces of the telescope and the magnification-varying lens to become an unnecessary light which enters an image pickup element that deteriorates the accuracy in the distance measuring.
The present invention is to provide an optical apparatus in which an occurrence of unnecessary light at lens surfaces can be suppressed.
To achieve the above described purpose, an optical apparatus as one aspect of the present invention is characterized in that an optical apparatus, includes: a deflecting unit configured to deflect an illumination ray from a light source to scan an object and deflect a reflected ray from the object; a light guiding unit configured to guide the illumination ray from the light source to the deflecting unit and to guide the reflected ray from the deflecting unit to a light receiving element; and an optical system having a plurality of lens surfaces, configured to guide the illumination ray from the deflecting unit to the object and to guide the reflected ray from the object to the deflecting unit, wherein a normal at an incident point of the illumination ray on each of the plurality of lens surfaces and the illumination ray are not parallel to each other.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
A preferred embodiment of the present invention will be described below with reference to the drawings. Each drawing may be drawn to a scale different from the actual scale for convenience. In each of the drawings, the same member is denoted by the same reference numeral, and redundant description thereof is omitted.
The optical apparatus 1 can be used as a detection apparatus (image pickup apparatus) which detects (image pickup) the object 100 and a distance measuring device which acquires a distance (distance information) to the object 100, by receiving a reflected light from the object 100. The optical apparatus 1 according to the present embodiment uses a technique called LiDAR (Light Detection And Ranging), which calculates a distance to the object 100 based on time to receive reflected light from the object 100 or a phase of the reflected light.
The light source unit 10 includes a light source 11, an optical element 12, and stop 13. As the light source 11, semiconductor laser or the like which is a laser having a high energy concentration and good quality in directivity can be used. As will be described later, when the optical apparatus 1 is applied to an onboard system, there is a possibility that a human being is included in the object 100. Therefore, as the light source 11, it is desirable to adopt a device that emits infrared light, which has less influence to the human eye. The wavelength of an illumination light emitted from the light source 11 according to the present embodiment is 905 nm included in near-infrared region.
The optical element 12 has a function to change a degree of convergence of illumination light ejected from the light source 11. The optical element 12 according to the present embodiment is a collimator lens (light condensing element) which converts (collimates) diverged beam emitted from the light source 11 to a collimated beam. Here, the collimated beam includes not only strictly collimated beam but also approximately parallel beam such as slightly divergent beams and slightly convergent beams.
The stop 13 is a light shielding member in which an aperture is provided, which restricts the illumination light from the optical element 12 to determine its diameter of the beam (width of beam). The shape of the aperture of the stop 13 according to the present embodiment is an ellipse to match the shape of illumination light, but may be a shape other than ellipse if necessary. The diameter of the aperture of the stop 13 according to the present embodiment is 1.60 mm in X direction (major axis direction) and 1.30 mm in Z direction (minor axis direction).
The light guiding unit 20 is a member to separate an illumination path and a light receiving path from each other, guide the illumination light from the light source unit 10 to the deflecting unit 30, and to guide the reflected light reflected on the deflecting unit 30 to the light receiving unit 50. The light guiding unit 20 according to the present embodiment includes a transparent member 21, a perforated mirror (a with-hole mirror) 22, and a light receiving element 23 for light source. The transparent member 21 is a member for reflecting a part of the illumination light which has passed the aperture of the stop 13 and guiding the light to the light receiving element 23 for light source, and for which a glass substrate can be used, for example.
The perforated mirror 22 is a reflecting member provided with an opening (hole part) through which the illumination light from the light source unit 10 passes, and on which the reflected light from the deflecting unit 30 is reflected toward the light receiving unit 50 by a reflection region (reflecting part) other than the opening. The opening of the perforated mirror 22 according to the present embodiment is a cavity as shown in
The light receiving element 23 for light source is a device for photoelectrically converting the illumination light from the light source unit 10 and outputting a signal. For example, a sensor similar to the light receiving element 53 in a light receiving unit 50 described later can be used as the light receiving element 23. A signal output from the light receiving element 23 for light source is used when controlling unit 60, described later, controls the light source unit 10. Note that, if necessary, an optical element (such as a filter or a lens) for guiding light from the transparent member 21 to a light reception surface of the light receiving element 23 for light source may be disposed between the transparent member 21 and the light receiving element 23 for light source.
The deflecting unit 30 is a member for deflecting the illumination light from the light guiding unit 20 to scan an object 100, and for deflecting the reflected light from the object 100 to guide to the light guiding unit 20. The deflecting unit 30 according to the present embodiment is constituted by a folding mirror 31 and a scanning mirror (movable mirror) 32.
The scanning mirror 32 is preferably rockable about at least two axis (two axis scanning mirror) to allow a two-dimensional scanning of the object 100. For example, a Galvano mirror or a MEMS (Micro Electro Mechanical System) mirror can be employed as the scanning mirror 32. The scanning mirror 32 according to the present embodiment is a MEMS mirror having a swinging angle (shake angle) about the X axis of ±7 degrees, a swinging angle about the Y axis of ±16 degrees, and a swinging frequency of about 1 kHz.
The optical system 40 is a member for guiding the illumination light from the deflecting unit 30 to the object 100 and guide the reflected light reflected on the object 100 to the deflecting unit 30. The optical system 40 according to the present embodiment is an optical system constituted by a plurality of lenses 41 to 46 having refractive powers (powers) and not having a refractive power in the entire optical system (afocal optical system). Specifically, the optical system 40 is a telescope for enlarging the diameter of illumination beam from the deflecting unit 30 and reducing the diameter of the reflected beam from the object 100.
The scanning mirror 32 according to the present embodiment is arranged at a position of an entrance pupil of the optical system 40. The optical system 40 according to the present embodiment has an absolute value of the optical magnification (lateral magnification) D larger than 1 (|β|>1). Thus, a deflection angle of the principal ray of the illumination light emitted from the optical system 40 is smaller than a deflection angle of the principal light of the illumination light entering the optical system 40 after being deflected by the scanning mirror 32, to thereby improve a resolution in detecting an object.
An illumination light from the light source unit 10 is deflected by the deflecting unit 30 via the light guiding unit 20 and enlarged by the optical system 40 according to the optical magnification β to illuminate the object 100. The reflected light from the object 100 is reduced by the optical system 40 according to the optical magnification 1/β, and is deflected by the deflecting unit 30 to reach the light receiving unit 50. In this manner, the diameter of the illumination light can be enlarged by an arrangement of the optical system 40 on the object side of the deflecting unit 30.
Thus, since the diameter of the illumination beam can be further enlarged so that the spreading angle can be further reduced, sufficient illuminance and resolution can be secured even when the object is at a far distance. Further, by enlarging the pupil diameter by the optical system 40, more reflected light from the object can be taken in, so that a distance measured by the distance measuring and a distance measuring accuracy can be improved. Note that the optical system 40 may not be a telescope for reducing the diameter of the reflected light from the object, but may be an optical system that increases the diameter of the reflected light from the object as necessary. The optical system 40 may also not be an afocal optical system, and may optionally be an optical system having a refractive power in the entire system.
The light receiving unit (light receiving unit for distance measuring) 50 includes an optical filter 51, a condensing unit 52, and a light receiving element (light receiving element for distance measuring) 53. The optical filter 51 is a member that allows only intended light to pass through and blocks (absorbs) unnecessary light other than the intended light. The optical filter 51 according to the present embodiment is a band-pass filter which allows only light of wavelength bandwidth corresponding to the illumination light emitted from the light source 11 to pass through. The condensing unit 52 is a member for condensing a light having transmitted the optical filter 51 on the light receiving surface of the light receiving element 53, and is constituted by a single optical element (a condenser lens) in this embodiment. The configurations of the optical filter 51 and the condensing unit 52 are not limited to those in the present embodiment, in which the arrangement of each member may be swapped, and a plurality of the optical filters 51 and the condensing units may be included as necessary. For example, the condensing unit 52 may be constituted by a plurality of condenser lenses.
The light receiving element (light receiving element for distance measuring) 53 is an element (sensor) for receiving light from the condensing unit 52 to photoelectrically convert to output a signal. As a light receiving element 53, PD (Photo Diode), APD (Avalanche Photo Diode), SPAD (Single Photon Avalanche Diode) or the like can be employed. The reflected light from the object 100 illuminated by the illumination light is deflected by the deflecting unit 30 and reflected by a perforated mirror 22 to enter the light receiving element 53 via the optical filter 51 and the condensing unit 52.
The controlling unit 60 controls the light source 11, the light receiving element 23 for light source, the scanning mirror 32, the light receiving element 53, and the like. The controlling unit 60 is, for example, a processing unit (processor) such as a CPU (Central Processing Unit) or an arithmetic unit (computer) including the same. The controlling unit 60 drives each of the light source 11 and the scanning mirror 32 with a predetermined drive voltage and/or a predetermined drive frequency, and controls the output of the light source 11 (light amount of the illumination light) depending on a signal from the light receiving element 23 for light source. The controlling unit 60 may, for example, control the light source 11 to make the illumination light as a pulsed light, or perform an intensity modulation of the illumination light to generate a signal light.
The controlling unit 60 can also acquire a distance information of the object 100 based on a time period from a time (light emission time) at which the illumination light is emitted from the light source 11 to a time (light receiving time) at which the light receiving element 53 receives the reflected light from the object 100. At this time, the controlling unit 60 may acquire a signal from the light receiving element 53 at a particular frequency. Note that the distance information may be obtained based on a phase of the reflected light from the object 100 instead of based on the time period till a time the reflected light from the object 100 is received. More specifically, by obtaining a difference (phase difference) between a phase of a signal of the light source 11 and a signal output from the light receiving element 53 and multiplying the phase difference and a velocity of light, the distance information of the object 100 may be obtained.
The optical apparatus 1 as a distance measuring device using the LiDAR is suitable for an onboard system for identifying an object 100 such as a vehicle, a pedestrian, and an obstacle and controlling the own vehicle according to the distance information of the object 100. In case of using the LiDAR, a coaxial system in which an optical axis of the light source unit 10 and an optical axis of the light receiving unit 50 coincide to each other partially, or a non-coaxial system in which the optical axis do not coincide with each other may be adopted. The optical apparatus 1 according to the present embodiment is provided with the light guiding unit 20, thereby realizing a coaxial system while miniaturizing the entire apparatus.
In the onboard system or the like, it is required to detect an object at a short distance (about 1 m) to a long distance (about 300 m) from the optical apparatus 1 as the object 100. However, the strength of the reflected light (signal light) from the object 100 is very weak. For example, if the power of the illumination light emitted from the light source 11 is 1, the reflected light is about 10−7 to 10−8. The strength of the reflected light from the object 100 becomes smaller as the distance from the optical apparatus 1 to the object 100 is longer. For example, if the distance from the optical apparatus 1 to the object 100 is increased by 10 times, the strength of the reflected light which the optical apparatus 1 receives is decreased to about 1/100.
If the reflected light (dispersed light) which occurred unintentionally in each member in the optical apparatus 1, reaches the light receiving element 53 as unnecessary light, accuracy in measuring distance is affected. For example, if the ratio of unnecessary light to the signal light that the light receiving element 53 receives is increased, it becomes difficult to distinguish the signal light from the unnecessary light, and the accuracy in measuring distance is significantly deteriorated. It should be noted that there may be a method in which the light amount of the illumination light (the output of the light source 11) is increased in accordance with an increase of the distance to the object 100, but such method is not preferable because an influence on the human eye as the object 100 increases.
Such unnecessary light is likely to be caused at a lens surface disposed particularly in the image side of the light guiding unit 20. In the present embodiment, since the optical system 40 disposed closer to the object 100 than the light guiding unit 20 has a plurality of lenses, there is a possibility that the illumination light may become unnecessary light by being reflected (dispersed) at each of the lens surfaces. Therefore, in the present embodiment, in order to suppress the occurrence of the unnecessary light at each lens surface of the optical system 40, each lens is designed so that the illumination light is not perpendicularly incident on each lens surface. This will be described in detail below.
On the other hand, the illumination ray B indicated by the dotted line does not pass through the center of curvature C, and enters therefore the lens surface 4 in a certain incident angle. That is, a normal D at the incident point of the illumination ray B on the lens surface 4 and the illumination ray B are not parallel to each other (they do not overlap each other). Therefore, even if the illumination ray B is reflected by the lens surface 4, unnecessary light is not caused because the illumination ray B travels along an optical path different from the reflection optical path. Accordingly, in order to suppress the occurrence of the unnecessary light in the optical system 40, it is sufficient to arrange the deflecting unit 30 and the optical system 40 so that each of the illumination rays entering the lens surfaces does not pass through the centers of curvature of the lens surfaces (so as not to perpendicularly enter each of the lens surfaces).
Therefore, in the present embodiment, the deflecting unit 30 and the optical system 40 are arranged such that the normal at an incident point of the illumination ray in each of the lens surfaces of the optical system 40 and the illumination ray are not parallel to each other. Specifically, in a cross section (YZ cross section) including an illumination optical path and the deflection optical path, the deflecting unit 30 is arranged so that the optical path of the illumination ray in a central angle of view in a scanning range of the scanning mirror 32 and the optical axis of the optical system 40 are not coincide to each other. In addition, each lens of the optical system 40 is designed such that each illumination ray is not incident on each lens surface perpendicularly. Thus, the vertical entrance of the illumination ray to each lens surface of optical system 40 is suppressed, and the occurrence of unnecessary light can be sufficiently suppressed.
It should be noted that there are more than one method to prevent the illumination ray from vertically entering each of the lens surfaces. In the present embodiment, the deflecting unit 30 and the optical system 40 are arranged by being offset (shifted) from each other in Y direction, thereby reducing the vertical entrance of the illumination ray on each lens surface. However, a similar effect can be obtained by not shifting the deflecting unit 30 and the optical system 40 to each other but setting the scanning range of the deflecting unit 30 asymmetrically with respect to the optical axis of the optical system 40. Shifting and tilting may be combined.
Also, by using well-known optical simulation software or the like to check incident angle of each illumination ray on each lens surface in the optical system 40, it is possible to prevent the illumination ray from perpendicularly entering each lens surface. Design parameters for each lenses include, but is not limited to, a curvature (a radius of curvature), a thickness (a thickness in the optical axis direction), a surface shape, and a position (decentration) in the direction perpendicular to the optical axis. The shape of each lens surface may be aspherical surface, but it is desirable to use spherical surface in consideration of forming.
Let f denote the focal length of the condensing unit 52, H denote the maximum diameter of a light receiving surface of the light receiving element 53, and i denote the order of a lens surface of a plurality of lens surfaced in the optical system 40 when counting from the side of the deflecting unit 30. And, let Di-1 denote a direction cosine vector of the illumination ray entering the i-th lens surface, Si denote a normal vector at the incident point in the i-th lens surface, and Min denote the minimum value of cos−1 (Di-1·Si). It is desirable to satisfy the following inequality (1).
The inequality (1) shows a condition to suppress unnecessary light to enter the light receiving element 53 when the unnecessary light is caused at each of lens surfaces of the optical system 40. If the inequality (1) is not satisfied, it becomes difficult to suppress the unnecessary light generated at each of the lens surfaces of the optical system 40 to enter the light receiving element 53.
As described above, according to the optical apparatus 1 of the present embodiment, the occurrence of the unnecessary light in the lens surface can be suppressed. Thus, when the optical apparatus 1 is applied to a distance measuring device, a good accuracy in measuring distance can be realized without increasing the amount of light of illumination light. In addition, even when an infrared sensor having a lower sensitivity than a visible light sensor is used as the light receiving element 53, the distance information of the object 100 can be acquired at a higher accuracy.
Hereinafter, an optical apparatus according to the first embodiment of the present invention will be described. In the optical apparatus according to the present embodiment, a description of a configuration equivalent to the optical apparatus 1 according to the above-described embodiment is omitted.
The surface data of each lens surface of the optical system 40 and various data of the optical system 40 according to the present embodiment are shown below. In the surface data, r represents a radius of curvature [mm] of the lens surface and d represents a distance [mm] of adjacent lens surface gap. nd indicates a refractive index for d-line (wavelength 587.6 nm) of medium of the adjacent lens surface gap and vd indicates Abbe number with d-line as reference of the medium of the adjacent lens surface gap. In the various data, the tilt amount indicates an angle between the illumination ray and the optical axis of the optical system 40 at the central angle of view of the deflecting unit 30, and the shift amount indicates a distance between the incident point of the illumination ray on the deflection surface of the scanning mirror 32 and the optical axis of the optical system 40.
Surface Data
Various Data (YZ Cross Section)
As shown in the various data, the deflecting unit 30 according to the present embodiment is arranged such that the optical path of the illumination ray at the central angle of view in a scanning range of the scanning mirror 32 in YZ cross section and the optical axis of the optical system 40 do not coincide with each other. Specifically, the illumination ray at the central angle of view of the deflecting unit 30 does not coincide with the optical axis of the optical system 40 and they form an angle with each other (tilts to each other). In the deflection surface of the scanning mirror 32, the incident point of the illumination ray and the optical axis of optical system 40 are spaced apart from (shifted) each other. By arranging in this manner, it is also possible to obtain an effect that the incident angle of the axal beam to each lens surface can be reduced.
The values of the left side of the inequality (1) described above are shown for the respective lens surfaces in the optical system 40, below. In the present embodiment, since f=32.3 mm, H=0.5 mm and the right side of the inequality (1) is 0.0077, all lens surfaces satisfy inequality (1).
Left Side Value of the Inequality (1)
The optical apparatus according to the second embodiment of the present invention will be described below. In the optical apparatus according to the present embodiment, a description of a configuration equivalent to the optical apparatus according to the first embodiment described above is omitted.
Surface data of each lens surface of the optical system 40 and the various data of the optical system 40 according to the present embodiment are shown below.
Surface Data
Various Data (YZ Cross Section)
The values of the left side of the inequality (1) described above are shown for each of lens surfaces of the optical system 40, below. In this embodiment, as in the case of the first embodiment, since the right side of the inequality (1) is 0.0077, any lens surface satisfies the inequality (1).
Value of Left Side of Inequality (1)
The optical apparatus according to the third embodiment of the present invention will be described below. In the optical apparatus according to the present embodiment, a description of a configuration equivalent to the optical apparatus according to the first embodiment described above is omitted.
In the present embodiment, unlike the first and second embodiments, the illumination ray at the central angle of view of the deflecting unit 30 coincides with the optical axis of the optical system 40. On the other hand, in the deflection surface of the scanning mirror 32, the incident point of the illumination ray and the optical axis of the optical system 40 are spaced apart (shifted) from each other. With such an arrangement, since a ray at the central angle of view when emitted from the optical system 40 coincides with the optical axis of the optical system 40, a central position of the screen does not change even if the optical system 40 is removed from the optical apparatus. Accordingly, the angle of view can be changed by attaching/detaching the optical system 40 to/from the optical apparatus.
Surface data of each lens surface of the optical system 40 and various data of the optical system 40 according to the present embodiment are shown below.
Surface Data
Various Data (YZ Cross Section)
The values of the left side of the inequality (1) described above are shown for each of lens surfaces in the optical system 40 below. In this embodiment, as in the case of the first embodiment, since the right side of the inequality (1) is 0.0077, any lens surface satisfies the inequality (1).
Value of Left Side of Inequality (1)
[Onboard System]
As shown in
First, in step S1, based on a signal output from the light receiving unit 40 that receives a reflected light from an object around the vehicle that is illuminated by the light source unit 10 of the optical apparatus 1, the controlling unit 60 receives a distance information of the object. In step S2, the vehicle information acquisition device 200 acquires vehicle information including a vehicle speed, a yaw rate, a steering angle and the like. In step S3, by use of the distance information acquired in step S1 and the vehicle information acquired in step S2, the controlling unit 60 determines whether the distance to the object is included in a range of the preset setting distance.
Thus, it is possible to determine whether or not an object exists in the setting distance around the vehicle, and to determine the possibility of collision between the vehicle and the object. It should be noted that steps S1 and S2 may be performed in an order opposite to that described above, or may be performed in parallel with each other. When the object exists in the setting distance, the controlling unit 60 determines that “there is a possibility of collision” (step S4), and when the object does not exist in the setting distance, determines that “there is no possibility of collision” (step S5).
Next, when determining that “there is a possibility of collision”, the controlling unit 60 notifies (transmits) the determination result to the controlling unit 300 and the warning device 400. At this time, the controlling unit 300 controls the vehicle based on the determination result of the controlling unit 60 (step S6), and the warning device 400 performs warning to the user (driver) of the vehicle based on the determination result of the controlling unit 60 (step S7). The determination result may be notified to at least one of the controlling unit 300 and the warning device 400.
The controlling unit 300 controls a vehicle, for example, by applying a brake, returning an accelerator, turning a steering wheel, generating a control signal for generating a braking force on each wheel to suppress an output of an engine or a motor. In addition, the warning device 400 performs a screen operation such as emitting warning sound, displaying warning information on warning of a car navigation system or the like, or providing vibration to a seat belt or a steering wheel.
As described above, according to the onboard system 1000 of the present embodiment, the object can be detected and the distance can be measured by the above described process, to avoid a collision between the vehicle and the object. In particular, by applying the optical apparatus 1 according to each of the embodiments described above to the onboard system 1000, a high accuracy in measuring distance can be realized, so that the detection of an object and collision determination can be performed at a high accuracy.
In the present embodiment, the onboard system 1000 is applied to the driving support (collision damage reduction), but the present invention is not limited thereto, and the onboard system 1000 may be applied to a cruise control (including a cruise control with an adaptive cruise control function), an automatic driving, and the like. The onboard system 1000 is not limited to a vehicle such as an automobile, and can be applied to a moving member such as a ship, an aircraft, an industrial robot, and the like. The present invention is applicable not only to a moving member but also to various apparatuses utilizing object recognition such as an intelligent transport system (ITS) and a monitoring system.
The onboard system 1000 and the mobile device 500 may be provided with a notification device (notification unit) for notifying the manufacturer (manufacturer) of the onboard system or the distributor (dealer) of the mobile device of the fact that the mobile device 500 collides with an obstacle. For example, the notification device may be a device for transmitting information relating to a collision (collision information) between the mobile device 500 and an obstacle to a preset external notification destination by electronic mail or the like.
As described above, by adopting the configuration in which the notification device automatically notifies the collision information, it is possible to promptly take measures such as an inspection and a repair after the occurrence of collision. It should be noted that the notification destination of the collision information may be an insurance company, a medical institution, a police station, or any other destination set by the user. In addition, a notification device may be configured to notify a notification destination of not only the collision information, but also a failure information of each part or a consumption information of consumables. The presence/absence of the collision may be detected using the distance information obtained based on the output from the light receiving unit 2 described above, or may be detected by another detection unit (sensor).
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, variations deformation, and variations are possible within a range of the spirit thereof.
In each embodiment, each member is integrated (integrally supported), but each member may be configured as separate bodies if necessary. For example, the light guiding unit 20 or the deflecting unit 30 may be detachable from the light source unit 10 or the light receiving unit 50. In such case, a connecting member (connecting part) for connecting each other may be provided in a holding member (housing) for holding each member. In such case, in order to improve an accuracy of positioning between the light source unit 10 and the light guiding unit 20, the stop 13 may be provided in the light guiding unit 20 and is supported by a holding member common to a branch optical element.
According to the present invention, it is possible to provide an optical apparatus in which an occurrence of unnecessary light at lens surfaces can be suppressed.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-131060 | Jul 2019 | JP | national |
| 2020-012904 | Jan 2020 | JP | national |
This application is a Continuation of International Patent Application No. PCT/JP2020/027285, filed Jul. 13, 2020, which claims the benefit of Japanese Patent Application Nos. 2019-131060, filed Jul. 16, 2019, and 2020-012904, filed Jan. 29, 2020, all of which are hereby incorporated by reference herein in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2020/027285 | Jul 2020 | US |
| Child | 17560711 | US |
