JP2022152236A - Measurement device - Google Patents

Abstract

To provide a measurement device capable of maintaining high performance.SOLUTION: A measurement device is provided, comprising: a projection/reception optical system configured to irradiate an object with light and receive the light reflected by the object; a light source for supplying the light to the projection/reception optical system; a detector for detecting the light received by the projection/reception optical system; and a transmission route for transmitting the light between the projection/reception optical system and at least one of the light source and the detector.SELECTED DRAWING: Figure 2

Description

The present invention relates to measuring devices.

Distance measurement systems such as LiDAR (Light Detection and Ranging) use the TOF method ( Time of flight) is known. Further, in distance measurement systems such as LiDAR, laser light is scanned to measure over a wide range. For example, Patent Literature 1 describes a distance measurement system that two-dimensionally scans a laser beam.

Japanese Patent Publication No. 2021-500554

When a distance measurement system such as LiDAR is mounted in a housing such as a lamp, it is necessary to arrange devices constituting the distance measurement system in a narrow space. However, in addition to the effects of heat generated from fixtures such as lamps, the temperature inside the housing tends to rise because there is no place for heat to escape in a closed narrow space. A rise in temperature affects the performance of the devices, and there is a risk that the performance of the distance measurement system may deteriorate or malfunction.

SUMMARY OF THE INVENTION An object of the present invention is to provide a measuring apparatus capable of maintaining high performance.

In order to achieve the above object, as one aspect of the present invention, there is provided a projecting/receiving optical system for irradiating an object with light and receiving the light reflected by the object, and a light source for supplying light to the projecting/receiving optical system. a detector for detecting light received by the light projecting/receiving optical system; and a transmission line for transmitting light between the light projecting/receiving optical system and at least one of the light source and the detector. I will provide a.

In addition, the problems disclosed by the present application and their solutions will be clarified by the description of the mode for carrying out the invention and the drawings.

ADVANTAGE OF THE INVENTION According to this invention, the measuring apparatus which can maintain high performance is provided.

FIG. 1 is (a) a diagram showing a vehicle according to the first embodiment, and (b) an enlarged view within the Ib frame, showing the arrangement of the measuring device. FIG. 2 is a functional configuration diagram of the measuring device according to the first embodiment. FIG. 3 is a functional configuration diagram of the measurement apparatus according to the first embodiment, (a) a diagram showing a state in which the detector is arranged outside the housing, and (b) a state in which the light source is arranged outside the housing. It is a diagram. FIG. 4 is a functional configuration diagram of the measuring device according to the second embodiment. FIGS. 5A and 5B are diagrams showing examples of configurations of amplifiers, respectively, showing (a) a Fabry-Perot type (FP type) and (b) a ring resonator type (RO type). FIG. 6 shows an amplifier of the master oscillation power amplification type (MOPA type). FIG. 7 is a functional configuration diagram of the measurement apparatus according to the second embodiment, (a) a diagram showing a state in which the detector is arranged outside the housing, and (b) a state in which the light source is arranged outside the housing. It is a diagram. FIG. 8 is a diagram showing the arrangement of measuring devices according to a modification. Drawing of headlamps is omitted for ease of understanding. FIG. 9 is (a) a side view of the street light according to the modification, and (b) an enlarged view within the IXb frame, showing the arrangement of the measuring device.

<First Embodiment>
EMBODIMENT OF THE INVENTION Hereinafter, it demonstrates, referring drawings for one form for implementing this invention. In the following description, the same or similar configurations may be denoted by common reference numerals, and redundant description may be omitted.

<About the measuring device>
FIG. 1 is an explanatory diagram of a measuring device 1 and a vehicle 70 according to the first embodiment of the invention. The measuring device 1 is a device for measuring the surface of the object 90 and is mounted on the vehicle 70 .

In the following description, each direction is defined as shown in FIG. The direction along the optical axis of the light receiving optical system 32 (or the light projecting optical system 31) is defined as the Z direction. Note that the object 90 to be measured by the measuring device 1 is separated from the measuring device 1 in the Z direction. The direction perpendicular to the Z direction and in which the light projecting optical system 31 and the light receiving optical system 32 are arranged is defined as the X direction. A direction perpendicular to the Z direction and the X direction is defined as the Y direction. In particular, with respect to the Z direction, forward and backward are determined based on the traveling direction of the vehicle 70 .

A vehicle 70 includes a headlamp 71 and a bumper 72 , and the measuring device 1 is installed across the inside and outside of a housing 71A of the headlamp 71 . The housing 71A is a substantially rectangular parallelepiped hollow member, as shown in FIG. The headlamp 71 includes an LED (Light Emitting Diode) 71B that functions as a headlight source for the vehicle 70, and the LED 71B is supported by the rear side wall of the housing 71A. The headlight source of the vehicle 70 may be a semiconductor light-emitting element such as an LD (laser diode), an organic or inorganic EL (electroluminescence), or the like, instead of the LED 71B. Alternatively, a halogen lamp or an HID lamp (High Intensity Discharge lamp) may be used.

The measuring device 1 emits laser light from the light source 10 forward of the headlamp 71, detects reflected light reflected by the surface of the object 90, and calculates the distance to the object 90 based on the detection result.

The measurement apparatus 1 includes a light source 10, a detector 20, a light projecting/receiving optical system 30, a controller 40, a scanner 50, and optical fibers 60 and 61 (FIG. 2).

The light source 10 comprises a light emitting element that converts electrical signals into optical signals. For example, the light source 10 includes an LD chip (LD: Laser Diode) as a light emitting element and emits laser light. In the present embodiment, the method of emitting laser light from the light source 10 may be either a pulse type or a continuous irradiation type. The number of light emitting elements included in the light source 10 is appropriately set according to the configuration of the device, design conditions, and the like.

The detector 20 is a device that receives light from the light receiving optical system 32 via the optical fiber 61 and converts it into an electrical signal. The detector 20 is equipped with, for example, a PD chip (Photodiode) as a light receiving element, and is capable of receiving light. The number of light-receiving elements included in the detector 20 is appropriately set according to the configuration of the apparatus, design conditions, and the like. The detector 20 further includes a circuit that outputs the signal output from the light receiving element as an electrical signal. The output electrical signal is received and analyzed by the controller 40 .

Although the details will be described later, both the light source 10 and the detector 20 are not necessarily arranged outside the housing 71A. Either one may be arranged inside the housing 71A.

The light projecting/receiving optical system 30 is an optical system for irradiating the object 90 with laser light output from the light source 10 and causing the detector 20 to receive the reflected light from the object 90 . The light projecting/receiving optical system 30 has a light projecting optical system 31 and a light receiving optical system 32 .

The light projecting optical system 31 is an optical system for irradiating the object 90 with laser light output from the light source 10 . The light projecting optical system 31 receives the laser light emitted from the light source 10 via the optical fiber 60 and irradiates the object 90 with the laser light as collimated light. Collimated light is emitted in a predetermined direction (predetermined angle) according to the positional relationship between the light source 10 and the projection optical system 31 . The light source 10 irradiates the object 90 with light through the projection optical system 31 . The projection optical system 31 is composed of lens groups each composed of one or more (for example, 5 to 7) lenses (in FIG. 2, the lens groups of the projection optical system 31 are simply shown. ), in particular with a collimating lens facing the front end of the optical fiber 60 .

The light receiving optical system 32 is an optical system for causing the detector 20 to receive reflected light from the object 90 . A detector 20 is arranged in the focal plane of the receiving optical system 32 . The reflected light incident on the light receiving optical system 32 is transmitted through the optical fiber 60 and received by the detector 20 . The light-receiving optical system 32, like the light-projecting optical system 31, is each composed of a lens group composed of one or more (for example, 5 to 7) lenses (in FIG. 2, the lens group of the light-receiving optical system 32 is shown for simplicity).

The scanner 50 has a function of scanning laser light by changing the positional relationship of the light source 10 with respect to the light projecting/receiving optical system 30 and changing the angle at which the laser light is irradiated.

As for the configuration of the scanner 50 and the scanning method of the laser light, various ones such as photonic crystals and liquid crystals can be adopted. For example, the scanner 50 may have a mirror that rotates or moves, such as a galvanometer scanner or a MEMS mirror, so that the laser beam is reflected by the mirror and scanned with the laser beam. The mirrors may be one or more plane mirrors, or may be formed in a polyhedral shape.

Alternatively, the scanner 50 may be provided with a driving device such as a motor, and the laser beam may be scanned by moving the projection optical system 31 in the XY directions. This is a method adopted when the measuring device 1 performs monitoring by the phased array method.

The scanned laser light is irradiated to the outside of the vehicle 70 through the housing 71A. Laser light scanning may be performed such that the scanning trajectory draws a geometric shape such as a Lissajous curve, or may be performed multiple times by shifting line scanning in the X direction (or Y direction) in the Y direction (or X direction). Performed in a variety of ways, such as by doing. Scanning in one dimension may be performed instead of scanning in two dimensions. Also, scanning may not be performed. If scanning is not performed, the measuring device 1 does not have to be equipped with the scanner 50 .

The controller 40 is a control unit that controls the measurement device 1 and is electrically connected to the light source 10 and the detector 20 respectively. The controller 40 controls emission of laser light from the light source 10 . Also, the controller 40 calculates the distance to the object 90 based on the output signal of the detector 20 .

The controller 40 has an arithmetic device 41 and a storage device 42 . The computing device 41 is, for example, a computing processing device such as a CPU or a GPU. The storage device 42 is configured by a main storage device and an auxiliary storage device, and stores programs and data. By executing the program stored in the storage device 42 by the arithmetic device 41, the arithmetic device 41 controls the emission of the laser light from the light source 10, and detects the object 90 based on the output signal of the detector 20. Calculate the distance to The computing device 41 also calculates the X, Y, and Z coordinates of the surface of the object 90 based on the output signal of the detector 20 .

The computing device 41 measures the distance to the object 90 (measures the surface coordinates of the object 90) by controlling the light source 10 and the detector 20, for example, by the TOF method (Time of Flight). As an example, measurement by the TOF method will be described below. In this case, the arithmetic device 41 measures the time from when the laser light is projected from the light source 10 until the detector 20 receives the reflected light. measures the distance to the object 90 by . In addition, the X, Y, and Z coordinates of the surface of the object 90 can be measured using the fact that laser light is emitted in a predetermined direction and reflected light in a predetermined direction is received.

The arithmetic device 41 may store the acquired coordinate data in the storage device 42 or in an external storage device. The data of the X, Y, and Z coordinates of many points on the surface of the object 90 become data representing a three-dimensional image (point group: point cloud) of the surface of the object 90 . The arithmetic device 41 may analyze the object 90 based on the three-dimensional image stored in the storage device 42 by executing the program stored in the storage device 42 .

The optical fibers 60 and 61 are members that function as transmission lines for transmitting light, pass through the rear side wall of the housing 71A, and are installed over the inside and outside of the housing 71A. Such an arrangement allows members such as the controller 40 to be arranged behind the headlamp 71 . By arranging some of the members outside the housing 71A, it is possible to prevent or reduce deterioration in the performance of the measuring device 1, particularly the PD or LD, due to the heat generated from the LED 71B. In addition, since there is no need to house the entire measuring device 1 inside the housing 71A, the measuring device 1 can be designed without being subject to restrictions on the dimensions of the housing 71A.

The optical fiber 60 transmits light between the light projecting optical system 31 and the light source 10 , and the optical fiber 61 transmits light between the light receiving optical system 32 and the detector 20 . Specifically, the laser light emitted from the light source 10 is transmitted forward through the optical fiber 60 and reaches the projection optical system 31 . The laser light emitted from the projection optical system 31 is irradiated toward the target object 90 while being scanned by the scanner 50 . Reflected light from the object 90 is received by the light receiving optical system 32 . The laser light emitted from the light receiving optical system 32 is transmitted backward through the optical fiber 61 and received and detected by the detector 20 .

As shown in FIG. 3, the measuring apparatus 1 may be configured to include only one of the optical fibers 60 and 61, and either the light source 10 or the detector 20 may be arranged outside the housing 71A. . Even with such a configuration, since a part of the measuring device 1 is arranged outside the housing 71A, the effect of the heat generated from the LED 71B, especially the control board thereof, and the heat generated from the measuring device 1 itself , the deterioration of the performance of the measuring device 1 can be prevented or reduced. In addition, since there is no need to house the entire measuring device 1 inside the housing 71A, the measuring device 1 can be designed without being subject to restrictions on the dimensions of the housing 71A.

<Second embodiment>
In the first embodiment, optical fibers 60 and 61 connect the light projecting and receiving optical system 30 to the light source 10 and the detector 20 to transmit light. It is also possible to add a member for preventing attenuation of light to this configuration. A second embodiment will be described below.

A measuring device 100 according to a second embodiment is shown in FIG. The measurement apparatus 100 includes a light source 10, a detector 20, a light projecting/receiving optical system 30, a controller 40, a scanner 50, and optical fibers 60 and 61, and is installed across the inside and outside of the housing 71A. be. These configurations are the same as those of the first embodiment.

The measuring device 100 further comprises two amplifiers 80 installed in each of the optical fibers 60,61. The amplifier 80 is a device that prevents or amplifies light transmitted inside the optical fibers 60 and 61 .

Various specific configurations of the amplifier 80 may be employed. 5 and 6 show specific configuration examples of a Fabry-Perot type (FP type), a ring resonator type (RO type), and a master oscillation power amplification type (MOPA type), respectively. The specific configuration of the amplifier 80 is appropriately selected and set according to the performance and device configuration required for the measuring device 100, design conditions, and the like. It is also possible to integrate the configuration for realizing the amplification function into one member and function as one module or device.

FIG. 5(a) shows an amplifier 80 in the FP configuration. In this case, the amplifier 80 has an optical coupler 81 , an FBG (Fiber Bragg Grating) 82 , a rare-earth-doped optical fiber 83 , and an excitation LD 84 . The FP-type amplifier 80 is suitable for amplifying continuous irradiation lasers.

During amplification, pumping light is oscillated from the pumping LD 84 and passes through the optical fibers 60 and 61 via the optical coupler 81 . When the pumping light passes through the rare-earth-doped optical fiber 83, the charges reversed by the pumping LD 84 are stimulated to oscillate, and the oscillated laser light travels back and forth between the two FBGs 82 and is amplified. Amplification of the light is achieved by transmitting the amplified pumping light to the optical fibers 60 and 61 .

FIG. 5(b) shows an amplifier 80 having an RO configuration. The amplifier 80 in this example has two optical couplers 81 , a rare earth doped optical fiber 83 , a pumping LD 84 and an isolator 85 . The RO type amplifier 80 is suitable for amplifying continuous irradiation lasers.

Pumping light emitted from the pumping LD 84 is unidirectionally transmitted by the isolator 85 and amplified within the rare-earth-doped optical fiber 83 . Amplification of the light is achieved by transmitting the amplified pumping light to the optical fibers 60 and 61 .

FIG. 6 shows an amplifier 80 configured to include a MOPA-type fiber laser. In the MOPA type, a combination of a pumping LD 84 and a rare-earth-doped optical fiber 83 is provided at two locations with a band-pass filter (BPF) 86 for preventing transmission of a specific wavelength and an isolator 85 interposed therebetween for two-stage amplification. is done. The MOPA type amplifier 80 is suitable for amplifying a pulsed laser, and is therefore suitable when the TOF detection method is adopted for the measuring apparatus 1 . If the output is sufficient, it is not always necessary to use two stages of amplification, and the arrangement of the combination of the pumping LD 84 and the rare earth-doped optical fiber 83 can be set at only one location.

There are also various methods or locations for arranging the amplifier 80 . As shown in FIG. 7, the amplifier 80 may be provided in either of the optical fibers 60 and 61 instead of both.

As shown in FIG. 7, the light source 10 and the detector 20 are not necessarily arranged outside the housing 71A. places are set. Also, an amplifier 80 may be provided between the controller 40 and the detector 20 .

By configuring as described above, it is possible to prevent attenuation of the laser light during transmission through the optical fibers 60 and 61 or to amplify the laser light. Therefore, it is possible to prevent or improve the performance of the measuring device 100 .

<Modification>
An embodiment in which the measuring devices 1 and 100 are installed on the housing 71A of the headlamp 71 has been described above. The present invention is not limited to this embodiment, and for example, as shown in FIG. As in the first and second embodiments, the measuring devices 1 and 100 are arranged inside and outside the housing 72A that constitutes the bumper 72. As shown in FIG. In addition, drawing of the headlamp 71 is omitted in FIG. 8 for easy understanding.

Moreover, the installation target of the measuring devices 1 and 100 is not limited to the vehicle 70, and installation to various machines and instruments is possible. As an example, as shown in FIG. 9, the measuring devices 1 and 100 can be installed in the lighting fixture 111 of the street light 110. FIG. As in the first and second embodiments, the measurement devices 1 and 100 are arranged inside and outside the housing 111A that constitutes the lamp 111. As shown in FIG. In this case, it is preferable to install the measuring devices 1 and 100 so as to pass through a side portion of the housing 111A that supports an illumination light source such as a light bulb.

In the example of FIG. 9, the measuring devices 1 and 100 are used as devices for measuring or monitoring pedestrians and vehicles passing around the streetlight 110 .

<effect>
The measurement apparatus 1 and 100 in each of the above-described embodiments and modifications includes a light projecting/receiving optical system 30 that irradiates an object 90 with light and receives the light reflected by the object 90, and supplies light to the light projecting/receiving optical system 30. and a detector 20 for detecting light received by the light projecting/receiving optical system 30 . Furthermore, the measurement devices 1 and 100 are provided with optical fibers 60 and 61 (corresponding to transmission lines of the present invention) that transmit light between the light projecting/receiving optical system 30 and at least one of the light source 10 and the detector 20 .

By providing the optical fibers 60, 61, it is possible to dispose a part of the measuring devices 1, 100, particularly the members whose output and detection performance depend on the temperature, outside the housings 71A, 72A, 111A. It is possible to prevent or reduce performance degradation of the measurement device 1 due to the influence of heat generated from the light source, substrate, or the like. In particular, by removing the light source 10 and the detector 20 from the influence of temperature, the thermal lens effect and the thermal birefringence effect can be suppressed, and effects such as maintaining the beam cross-sectional shape can be obtained. In addition, since there is no need to house the entire measuring apparatus 1, 100 inside the housings 71A, 72A, 111A, the measuring apparatus 1 can be designed without being subject to the limitations of the dimensions of the housings 71A, 72A, 111A. It becomes possible. Therefore, the measuring device 1, 100 can maintain high performance.

The light projecting/receiving optical system 30 includes a light projecting optical system 31 that irradiates an object 90 with light from the light source 10 and a light receiving optical system 32 that receives light reflected by the object 90 . Optical fibers 60 , 61 transmit light both between light source 10 and projecting optics 31 and between receiving optics 32 and detector 20 .

With such a configuration, the light source 10 and the detector 20 can be arranged outside the housings 71A, 72A, and 111A. It is possible to design the measuring device 1 without being restricted by the dimensions of the housings 71A, 72A, and 111A.

The measuring device 100 further comprises an amplifier 80 for amplifying the light in the optical fibers 60,61.

With the configuration as described above, attenuation of the laser light in the optical fibers 60 and 61 can be prevented or the laser light can be amplified. Therefore, it is possible to prevent or improve the measurement function of the measurement device 100 .

The light projecting/receiving optical system 30 is installed in predetermined housings 71A, 72A, and 111A. At least one of the light source 10 and the detector 20 is installed outside the housings 71A, 72A, 111A, and transmits light to and from the light projecting and receiving optical system 30 via the optical fibers 60, 61. conduct. Alternatively, both the light source 10 and the detector 20 are installed outside the enclosures 71A, 72A, 111A.

With the above configuration, variations in the method of arranging the light source 10 and the detector 20 are increased. The configuration of the measurement apparatus 1, 100 can be changed according to the required performance and the size of the housing, increasing the degree of freedom in design.

The housings 71A and 111A are housings for lamps. In particular, the housing 71A is a housing for a vehicle lamp.

By being installed in the housings 71A and 111A of the lamp having a member capable of transmitting light, the measurement apparatus 1 and 100 can easily obtain an environment suitable for laser light irradiation. In particular, by installing the measuring device 1, 100 in the headlamp 71, which is a vehicle lamp, it becomes easy to measure or monitor the area in front of the vehicle 70, which is necessary for automatic driving or the like.

measuring device 1, 100
light source 10
detector 20
Projection/reception optical system 30
controller 40
scanner 50
optical fibers 60, 61
vehicle 70
amplifier 80

Claims (7)

a projecting/receiving optical system for irradiating an object with light and receiving the light reflected by the object;
a light source that supplies light to the light projecting and receiving optical system;
a detector for detecting light received by the light projecting and receiving optical system;
A measurement apparatus comprising the light projecting/receiving optical system and a transmission line that transmits light between at least one of the light source and the detector. The light projecting and receiving optical system includes a light projecting optical system that irradiates the object with light from the light source, and a light receiving optical system that receives the light reflected by the object,
2. The measurement apparatus according to claim 1, wherein said transmission path transmits light both between said light source and said projecting optical system and between said receiving optical system and said detector. 3. The measuring apparatus according to claim 1, further comprising an amplifier that amplifies light in said transmission line. The light projecting and receiving optical system is installed in a predetermined housing,
4. The light source and the detector according to any one of claims 1 to 3, wherein at least one of the light source and the detector is installed outside the housing and transmits light to and from the light projecting/receiving optical system via the transmission path. The measurement device according to item 1. 5. The measuring device according to claim 4, wherein both the light source and the detector are located outside the housing. 6. The measuring device according to claim 4, wherein the housing is a housing of a lamp. 7. The measuring device according to claim 6, wherein the lamp is a vehicle lamp.

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