JP2024059877A - Optical device, distance measuring device, distance measuring method, program, and recording medium - Google Patents

Abstract

[Problem] To provide an optical device that complies with safety standards regarding the intensity of laser light and is capable of measuring the distance to a distant object with high accuracy. [Solution] The optical device has a plurality of light-projecting units, each of which includes a light source that emits an emitted light, and each of which emits the emitted light as irradiation light having an instantaneous irradiation field, and a light-receiving unit that includes a light-receiving element that receives light reflected from an object from the irradiation light, and whose instantaneous field of view is larger than the solid angle of each instantaneous irradiation field of the irradiation light, and on an irradiation surface located a predetermined distance from the light-receiving unit, the irradiation area formed by the instantaneous irradiation fields of the plurality of light-projecting units includes the field of view formed by the instantaneous field of view. [Selected Figure] Figure 1

Description

The present invention relates to an optical device that emits and receives emitted light, a distance measuring device that measures the distance to an object, a distance measuring method, a program, and a recording medium.

A distance measuring device including an optical device measures the distance to an object, i.e., measures distance, by, for example, scanning a target area with laser light. An example of such a distance measuring device is disclosed in Patent Document 1, which discloses an optical distance measuring device that includes an optical scanning unit with a swinging movable unit, a light source unit that emits pulsed light toward the light reflecting surface of the movable unit, a light receiving unit that receives the reflected light of the pulsed light, and a distance measuring unit that measures the distance to the object.

JP 2011-053137 A

When laser light is irradiated onto an object, it scatters. For this reason, the amount of laser light received by the distance measuring device decreases as the object being irradiated with the laser light becomes farther away from the distance measuring device. Therefore, in order to measure the distance to an object located far away from the distance measuring device, it is desirable to emit laser light with a high output.

However, laser light can be harmful to the human body if its power density is high. For this reason, safety standards limit the output of laser light. Therefore, when measuring the distance to an object located at a long distance, one of the issues is that with laser light that complies with safety standards, the amount of laser light received by the distance measuring device is reduced.

The present invention has been made in consideration of the above points, and one of its objectives is to provide an optical device that complies with safety standards regarding the intensity of laser light and is capable of accurately measuring the distance to an object located at a distance.

The optical device described in claim 1 of the present application has a plurality of light projecting units each including a light source that emits an emission light and each emitting the emission light as an illumination light having an instantaneous illumination field, and a light receiving unit including a light receiving element that receives the reflected light of the illumination light reflected by an object and having a solid angle of an instantaneous visual field larger than the solid angle of the instantaneous illumination field of each of the illumination lights, and is characterized in that, on an illumination surface located a predetermined distance from the light receiving unit, the illumination area formed by the instantaneous illumination fields of the plurality of light projecting units includes a visual field area formed by the instantaneous visual field.

The distance measuring device described in claim 7 of the present application is characterized in that it has a plurality of light projecting units, each of which includes a light source that emits an emitted light, and each of which emits the emitted light as an irradiated light having an instantaneous irradiation field, a light receiving unit, each of which includes a light receiving element that receives the reflected light of the irradiated light reflected by an object, and whose solid angle of the instantaneous field of view is larger than the solid angle of the instantaneous irradiation field of each of the irradiated lights, and has an optical device in which the irradiation area formed by the instantaneous irradiation fields of the plurality of light projecting units includes the field of view formed by the instantaneous field on an irradiation surface located at a predetermined distance from the light receiving unit, and a distance measuring unit that measures the distance to the object based on the emitted light and the reflected light.

The distance measuring method described in claim 8 of the present application is a distance measuring method performed by a distance measuring device having a plurality of light projecting units, each of which includes a light source that emits an emission light, and each of which emits the emission light as an illumination light having an instantaneous illumination field, and a light receiving unit, each of which includes a light receiving element that receives the reflected light of the emission light reflected by an object, and whose solid angle of the instantaneous visual field is larger than the solid angle of the instantaneous illumination field of each of the emission lights, and an optical device in which the illumination area formed by the instantaneous illumination fields of the plurality of light projecting units includes the visual field area formed by the instantaneous visual field on an illumination surface at a predetermined distance from the light receiving unit, and a distance measuring unit that measures the distance to the object based on the emission light and the reflected light, characterized in that the distance measuring method includes a step of simultaneously emitting the emission light from each of the plurality of light projecting units, a step of receiving the reflected light with the instantaneous visual field in the light receiving unit, and a step of measuring the distance to the object based on the emission light and the reflected light.

The program described in claim 9 of the present application is characterized in that the program causes a distance measuring device having a plurality of light projecting units, each of which includes a light source that emits emitted light, and each of which emits the emitted light as irradiation light having an instantaneous irradiation field, and a light receiving unit, each of which includes a light receiving element that receives reflected light of the emitted light reflected by an object, and whose solid angle of instantaneous visual field is larger than the solid angle of the instantaneous irradiation field of each of the emitted light, and an optical device in which an irradiation area formed by the instantaneous irradiation fields of the plurality of light projecting units includes a visual field area formed by the instantaneous visual field on an irradiation surface at a predetermined distance from the light receiving unit, and a distance measuring unit that measures the distance to the object based on the emitted light and the reflected light, to perform the steps of simultaneously emitting the irradiation light from each of the plurality of light projecting units, receiving the reflected light with the instantaneous visual field in the light receiving unit, and measuring the distance to the object based on the emitted light and the reflected light.

The recording medium described in claim 10 of the present application is characterized in that it has a plurality of light projecting units, each of which includes a light source that emits emitted light, and each of which emits the emitted light as irradiation light having an instantaneous irradiation field, and a light receiving unit, each of which includes a light receiving element that receives reflected light of the emitted light reflected by an object, and whose solid angle of instantaneous visual field is larger than the solid angle of the instantaneous irradiation field of each of the emitted light, and an optical device in which the illumination area formed by the instantaneous illumination fields of the plurality of light projecting units includes the visual field area formed by the instantaneous visual field on an irradiation surface at a predetermined distance from the light receiving unit, and a distance measuring unit that measures the distance to the object based on the emitted light and the reflected light, and has a program recorded thereon to cause the distance measuring device to perform the steps of simultaneously emitting the irradiation light from each of the plurality of light projecting units, receiving the reflected light with the instantaneous visual field in the light receiving unit, and measuring the distance to the object based on the emitted light and the reflected light.

1 is a block diagram showing a configuration of a distance measuring device according to a first embodiment; 3 is an explanatory diagram for explaining the operation principle of a light projection system of the distance measuring device according to the first embodiment. FIG. 3 is an explanatory diagram for explaining the operation principle of a light receiving system of the distance measuring device according to the first embodiment. FIG. 2 is a perspective view showing an example of the arrangement of a light projecting unit and a light receiving unit of the distance measuring device according to the first embodiment; FIG. 3 is a conceptual diagram illustrating an instantaneous irradiation field of the light projecting unit and an instantaneous visual field of the light receiving unit according to the distance from the distance measuring device of Example 1. FIG. 1 is a conceptual diagram for explaining the solid angle of an instantaneous irradiation field on a virtual plane at a predetermined distance from the distance measuring device of Example 1. FIG. 4 is a conceptual diagram for explaining a solid angle of an instantaneous field of view on a virtual plane at a predetermined distance from the distance measuring device according to the first embodiment. FIG. 1 is a conceptual diagram illustrating an instantaneous irradiation field and an instantaneous visual field on a virtual plane at a predetermined distance from a distance measuring device according to Example 1. FIG. 4 is a process flow showing a distance measuring method of the distance measuring device according to the first embodiment. 10 is a perspective view showing another example of the arrangement of the light projecting unit and the light receiving unit of the distance measuring device according to the first embodiment. FIG. 5 is an explanatory diagram showing another configuration example of the light projecting unit of the distance measuring device according to the first embodiment; FIG. FIG. 11 is a block diagram showing a configuration of a distance measuring device according to a second embodiment. FIG. 11 is a perspective view showing an example of the arrangement of a light projecting unit and a light receiving unit of a distance measuring device according to a third embodiment. A conceptual diagram explaining an instantaneous irradiation field and an instantaneous visual field on a virtual plane at a predetermined distance from a distance measuring device of Example 3. FIG. 11 is a perspective view showing another example of the arrangement of the light projecting unit and the light receiving unit of the distance measuring device according to the third embodiment. FIG. 13 is a perspective view showing another example of the arrangement of the light projecting unit and the light receiving unit of the distance measuring device according to the third embodiment.

Below, we will explain an example in which the optical device of the present invention is used in a distance measuring device.

Figure 1 shows the functional blocks of the distance measuring device 100 according to this embodiment. In Figure 1, the light projecting units 10a and 10b are light emitting devices that emit emitted light. The light projecting units 10a and 10b have the same configuration. The light source 11 of the light projecting units 10a and 10b is, for example, a laser element capable of emitting pulsed light as the emitted light.

The optical deflection element 12 is a device that deflects a light beam in response to a control signal. In other words, the optical deflection element 12 can deflect pulsed light in a variable direction. The optical deflection element 12 has an emitted light reflecting member that includes a light reflecting surface (not shown). The optical deflection element 12 may be a MEMS (Micro Electro Mechanical Systems) mirror device, a polygon mirror, or the like. Note that the optical deflection element 12 may also be an optical deflection element that does not have a light reflecting surface. An example of such an optical deflection element 12 is an acousto-optical deflector (AO deflector).

The light deflection element 12 can reflect the pulsed light emitted from the light source 11 at its light reflecting surface and emit irradiation light toward a predetermined area to be scanned (hereinafter referred to as the scanning area). Therefore, the light deflection element 12 functions as an emitted light polarization element.

In this way, the light projectors 10a and 10b each emit the output light polarized by the optical deflection element 12 toward the scanning target area as irradiation light having an instantaneous irradiation field. The irradiation light is reflected by an object present in the scanning target area. The irradiation light reflected by the object travels toward the distance measuring device 100 as reflected light.

The light receiving unit 20 is a light receiving device that receives reflected light and generates a light receiving signal, which is an electrical signal. The light deflection element 21 is a device that can deflect a light beam in response to a control signal. In other words, the light deflection element 21 can deflect the reflected light, which is the irradiated light reflected by an object, in a variable direction. The light deflection element 21 has a reflected light reflecting member that includes a light reflecting surface (not shown). As with the light deflection element 12, the light deflection element 21 can be a MEMS mirror device or the like. Therefore, the light deflection element 21 functions as a reflective light deflection element.

The light receiving element 22 receives the reflected light deflected by the light deflection element 21 and generates a light receiving signal, which is an electrical signal. For example, an avalanche photodiode can be used as the light receiving element 22.

The control unit 30 controls the pulsed light emitted from the light source 11 of each of the light projectors 10a and 10b, as well as the angle of the light reflecting surface of the light deflection element 21 of the light receiving unit 20 and the light deflection element 12 of each of the light projectors 10a and 10b. The control unit 30 is a computer that has at least a central processing unit, a main memory device, and an auxiliary memory device.

The light source control unit 31 controls the light emission of each of the light sources 11 of the light projecting units 10a and 10b. Specifically, the light emission is controlled by referring to a table (not shown) that specifies the light emission timing so that the light source 11 emits pulsed light.

The mirror control unit 32 controls the angle of inclination of the light reflecting surface of the light deflection element 12 of each of the light projectors 10a and 10b. Specifically, the mirror control unit 32 reflects pulsed light at the light reflecting surface of the light deflection element 12, and controls the angle of inclination of the light reflecting surface of the light deflection element 12 so that the reflected irradiation light scans the scanning target area.

The mirror control unit 32 controls the angle of inclination of the light reflecting surface of the light deflection element 21 of the light receiving unit 20. Specifically, the mirror control unit 32 controls the inclination of the light reflecting surface of the light deflection element 21 so that the direction (angle of inclination) of the light reflecting surface of the light deflection element 21 of the light receiving unit 20 and the direction (angle of inclination) of the light reflecting surface of the light deflection element 12 of the light projecting units 10a and 10b are linked. In other words, the reflected light travels toward the light receiving element 22 by linking the direction of the light reflecting surface of the light deflection element 21 of the light receiving unit 20 and the direction of the light reflecting surface of the light deflection element 12 of the light projecting units 10a and 10b.

In other words, the light source control unit 31 and the mirror control unit 32 function as an emission control means for simultaneously emitting pulsed light from each of the light projecting units 10a and 10b. In addition, the mirror control unit 32 functions as a light receiving means for causing the light receiving unit 20 to receive reflected light.

The distance measurement unit 33, which serves as a distance measurement unit, calculates the distance from the distance measurement device 100 to an object within the scanning target area. In other words, the distance measurement unit 33 functions as a distance measurement means that measures the distance to an object based on the pulsed light and the reflected light.

The distance measurement unit 33 calculates the distance from the distance measuring device 100 to an object in the scanning area based on the light receiving signal generated by the light receiving element 22. For example, the distance measurement unit 33 calculates the distance using a time-of-flight method. Note that the calculation of the distance to the object is not limited to the time-of-flight method, and may also be a phase difference method.

Specifically, the distance measurement unit 33 acquires the emission time of one pulse of light emitted by the light source 11 and the reception time at which the irradiated light resulting from the deflection of the one pulse of light is reflected by an object in the scanning target area and detected as reflected light by the light receiving element 22. Then, the distance between the distance measuring device 100 and the object is calculated based on the time difference between the emission time and the reception time.

In addition, a virtual irradiation surface (not shown) is provided in the traveling direction of the irradiation light deflected by the light deflection element 12. In addition, the irradiation surface does not actually exist.

Figure 2 is a conceptual diagram showing the operation of a light projection system including light projection units 10a and 10b. In Figure 2, pulsed light EL1 emitted from light source 11 is incident on light reflecting surface MR of light deflection element 12.

The optical deflection element 12 reflects the pulsed light EL1 incident on the optical reflection surface MR. That is, the optical deflection element 12 deflects the pulsed light EL1 as irradiation light EL2 toward the scanning target region R.

The light reflecting surface MR of the light deflection element 12 is fixed to the main body so that it can swing freely. Therefore, the light deflection element 12 deflects the traveling direction of the irradiation light EL2 in the desired direction within the scanning target area R by swinging the light reflecting surface MR.

The irradiation light EL2 is deflected by the optical deflection element 12 so that a desired trajectory is traced on the irradiation surface VS. In addition, the trajectory traced on the irradiation surface VS is preferably a raster scanning trajectory, a Lissajous scanning trajectory, or the like, but is not limited to these.

Figure 3 is a conceptual diagram showing the operation of the light receiving system of the light receiving unit 20. In Figure 3, the irradiation light EL2 is reflected by an object OB present in the scanning target area R. The irradiation light EL2 reflected by the object OB travels toward the light receiving unit 20 as reflected light RL. When the reflected light RL is reflected by the light reflecting surface MR of the light deflection element 21 of the light receiving unit 20, it enters the light receiving element 22.

The light receiving element 22 generates a light receiving signal based on the incident reflected light RL and supplies the generated light receiving signal to the control unit 30. The distance measurement unit 33 of the control unit 30 measures the distance to the object OB based on the time when the pulsed light EL1 is emitted and the time when the reflected light RL is received.

Figure 4 shows an example of the arrangement of the light-projecting units 10a, 10b and the light-receiving unit 20 of the distance measuring device 100 according to this embodiment. As shown in Figure 4, the light-projecting units 10a, 10b are arranged in a row on the substrate 40 so as to sandwich the light-receiving unit 20 between them.

The light-projecting units 10a and 10b are also positioned at equal distances to the light-receiving unit 20. Specifically, the distance LH1 from the light-receiving unit 20 to the light-projecting unit 10a is equal to the distance LH2 from the light-receiving unit 20 to the light-projecting unit 10b.

Figure 5 shows the instantaneous field of illumination (iFOI) of the light projecting units 10 and 10b and the instantaneous field of view (iFOV) of the light receiving unit 20. The dashed arrow in the figure indicates the direction of travel of the irradiation light EL2.

Specifically, FIG. 5 shows cross sections of the instantaneous field of interest (iFOI) of the light projectors 10a and 10b and the instantaneous field of view (iFOV) of the light receiver 20 in a direction perpendicular to the direction of travel of the irradiation light EL2 indicated by the dashed arrow in the figure, according to the distance from the distance measuring device 100.

The instantaneous field of interest (iFOI) is the area irradiated with the emitted light EL at the moment of interest. For example, the instantaneous field of interest (iFOI) is the angular range into which the light source shape (not shown) is projected by the projection lenses (not shown) of the light projectors 10a and 10b, or the sum of the angular ranges, and the instantaneous field of view (iFOV) is the angular range into which the light receiving surface of the light receiving unit 20 is viewed by the light receiving lens of the light receiving unit 20.

The two-dot chain lines in the figure indicate the instantaneous irradiation field (iFOI(a)) of the light projector 10a and the instantaneous irradiation field (iFOI(b)) of the light projector 10b. Also, the one-dot chain line in the figure indicates the instantaneous field of view (iFOV) of the light receiver 20.

The light projecting units 10a and 10b each emit irradiation light EL2 with an output that satisfies a safety standard. The safety standard is determined based on the light intensity at a predetermined distance from the distance measuring device 100. For example, the safety standard is determined based on the light intensity at 100 mm from the distance measuring device 100. In addition, the instantaneous irradiation field (iFOI(a), iFOI(b)) of the emitted light EL emitted by the light projecting units 10a and 10b is smaller than the instantaneous field of view (iFOV).

Depending on the distance from the distance measuring device 100, the positional relationship of each of the instantaneous irradiation fields (iFOI(a), iFOI(b)) within the instantaneous field of view (iFOV) changes. Specifically, as the distance from the distance measuring device 100 increases, the instantaneous irradiation fields (iFOI(a), iFOI(b)) approach each other and come into contact with each other at a predetermined distance from the distance measuring device 100.

Distances L1 to L4 are distances from the distance measuring device 100. For example, distances L1 to L4 are distances from the light receiving unit 20. Distances L1 to L4 may also be distances from the light projecting unit 10a or the light projecting unit 10b.

Distance L1 is the distance from the distance measuring device 100 as determined by safety standards. At the position of distance L1, the instantaneous irradiation field (iFOI(a)) of the light projecting unit 10a and the instantaneous irradiation field (iFOI(b)) of the light projecting unit 10b are located outside the instantaneous field of view (iFOV) of the light receiving unit 20.

Therefore, the intensity of the irradiation light EL2 emitted by the light projectors 10a and 10b at the position of distance L1 meets the safety standard. Note that at the position of distance L1, either or both of the instantaneous irradiation field (iFOI(a)) of the light projector 10a and the instantaneous irradiation field (iFOI(b)) of the light projector 10b may be located inside the instantaneous field of view (iFOV) of the light receiver 20. In this case, it is advisable to adjust the output of the irradiation light EL2 as appropriate so as to meet the safety standard at the position of distance L1.

Distance L2 is the distance from the distance measuring device 100 and is longer than distance L1. Distance L2 is, for example, 50 m from the distance measuring device 100. At the position of distance L2, the instantaneous irradiation field (iFOI(a)) of the light projecting unit 10a and a part of the instantaneous irradiation field (iFOI(b)) of the light projecting unit 10b are arranged inside the instantaneous field of view (iFOV) of the light receiving unit 20. Therefore, when an object OB is present at the position of distance L2, the light receiving unit 20 can obtain sufficient reflected light RL to measure the distance of the object OB. Therefore, the distance measuring device 100 can measure the distance of an object OB that is present at a distance farther than distance L2.

Distance L3 is the distance from the distance measuring device 100 and is longer than distance L2. Distance L3 is, for example, 100 m from the distance measuring device 100. At the position of distance L3, a part of the instantaneous irradiation field (iFOI(a)) of the light projecting unit 10a and the instantaneous irradiation field (iFOI(b)) of the light projecting unit 10b are disposed inside the instantaneous field of view (iFOV) of the light receiving unit 20.

In addition, at distance L3, the proportion of the area of the instantaneous irradiation field (iFOI(a)) of light projector 10a and the instantaneous irradiation field (iFOI(b)) of light projector 10b that is disposed inside the instantaneous field of view (iFOV) of light receiver 20 is greater than at distance L2.

Therefore, when an object OB is present at a position of distance L3, the light receiving unit 20 can obtain sufficient reflected light RL to measure the distance to the object OB. Therefore, the distance measuring device 100 can measure the distance in a state where the density of the instantaneous illumination field (iFOI) arranged within the instantaneous field of view (iFOV) is higher than when the object OB is present at distance L2.

Distance L4 is the distance from the distance measuring device 100 and is longer than distance L3. Distance L4 is, for example, 200 m from the distance measuring device 100.

At the distance L4, the instantaneous irradiation field (iFOI(a)) of the light projector 10a and the instantaneous irradiation field (iFOI(b)) of the light projector 10b are located inside the instantaneous field of view (iFOV) of the light receiver 20.

In other words, the proportion of the area of the instantaneous irradiation field (iFOI(a)) of the light projector 10a and the instantaneous irradiation field (iFOI(b)) of the light projector 10b that is disposed inside the instantaneous field of view (iFOV) of the light receiver 20 at distance L4 is greater than that at distance L3.

Therefore, when an object OB is present at a position of distance L4, the light receiving unit 20 can obtain sufficient reflected light RL to measure the distance to the object OB. Therefore, the distance measuring device 100 can measure the distance in a state where the density of the instantaneous illumination field (iFOI) arranged within the instantaneous field of view (iFOV) is higher than when the object OB is present at distance L3.

Figure 6A shows the instantaneous irradiation fields (iFOI(a), iFOI(b)) on the irradiation surface VS at the distance L4 in Figure 5. In Figure 6A, the irradiation surface VS is disposed at a predetermined distance (r) from the light source 11. The instantaneous irradiation fields (iFOI(a), iFOI(b)) of the light source 11 of the light projectors 10a and 10b are shown on the irradiation surface VS.

The instantaneous irradiation field (iFOI(a), iFOI(b)) on the irradiation surface VS is shown as a rectangle. Note that the instantaneous irradiation field (iFOI(a), iFOI(b)) on the irradiation surface VS is not limited to a rectangular shape, and the light source 11 may be configured to be, for example, circular or elliptical.

Here, a solid angle refers to the area enclosed by a cone surface formed by the movement of a half line emanating from the same point in space. A solid angle can be expressed as the size of the area that the cone surface cuts out from a sphere of radius 1 centered on that point.

In this embodiment, when the same point in space is the light source 11, the solid angle through which the light source 11 views the instantaneous irradiation field (iFOI(a), iFOI(b)) is represented by the instantaneous irradiation field (iFOI(a), iFOI(b)) on the irradiation surface VS. The line connecting the center CI of the instantaneous irradiation field (iFOI(a), iFOI(b)) and the light source 11 is defined as the axis AX1.

Figure 6B shows the instantaneous field of view (iFOV) at the irradiation surface VS at the distance L4 in Figure 5. In Figure 6B, the irradiation surface VS is located at a predetermined distance (r) from the light receiving element 22. That is, the distance from the light source 11 to the irradiation surface VS in Figure 6A is equal to the distance from the light receiving element 22 to the irradiation surface VS.

The instantaneous field of view (iFOV) of the light receiving unit 20 is shown on the irradiation surface VS. The instantaneous field of view (iFOV) on the irradiation surface VS is shown as a rectangle. Note that the instantaneous field of view (iFOV) on the irradiation surface VS is not limited to a rectangular shape, and the light receiving element 22 of the light receiving unit 20 may be configured to be, for example, circular or elliptical.

Inside the instantaneous field of view (iFOV) on the irradiation surface VS, the instantaneous irradiation field (iFOI(a), iFOI(b)) shown in FIG. 6A is shown. The instantaneous field of view (iFOV) on the irradiation surface VS is larger than the instantaneous irradiation field (iFOI(a), iFOI(b)).

In this embodiment, if the same point in space is the light receiving element 22, the solid angle through which the light receiving element 22 sees the instantaneous field of view (iFOV) is expressed as the instantaneous field of view (iFOV) on the irradiation surface VS.

Therefore, the solid angle through which the light source 11 views the instantaneous irradiation field (iFOI(a), iFOI(b)) is smaller than the solid angle through which the light receiving element 22 views the instantaneous field of view (iFOV). In other words, the solid angle through which the light receiving element 22 views the instantaneous field of view (iFOV) is larger than the solid angle through which the light source 11 views the instantaneous irradiation field (iFOI(a), iFOI(b)). The line connecting the center CV of the instantaneous field of view (iFOV) and the light receiving element 22 is defined as the axis AX2.

Figure 6C shows the instantaneous irradiation field (iFOI(a), iFOI(b)) and the instantaneous field of view (iFOV) on the irradiation surface VS located at a distance L4. Note that the instantaneous irradiation field (iFOI(a), iFOI(b)) and the instantaneous field of view (iFOV) on the irradiation surface VS are shown in a rectangular shape.

As shown in FIG. 6C, in the irradiation surface VS located at the distance L4, the irradiation area RI is formed by the instantaneous irradiation fields (iFOI(a), iFOI(b)) of each of the light projectors 10a and 10b. The irradiation area RI is the area illuminated by each of the light projectors 10a and 10b.

The irradiation area RI is, for example, an area on the irradiation surface VS located at a distance L4 where the irradiation light EL2 is irradiated, and has at least half the brightness of the irradiation light EL2 at the center of the area.

The visual field RV is formed by the instantaneous field of view (iFOV) of the light receiving unit 20 at the irradiation surface VS located at the distance L4. The irradiation area RI includes the entire visual field RV at the irradiation surface VS located at the distance L4.

The position on the scanning target region R where the irradiation region RI includes the entire instantaneous field of view RV, i.e., the distance from the distance measuring device 100, can be adjusted as appropriate. For example, the distance from the distance measuring device 100 may be a distance closer to the distance measuring device 100 than distance L4, such as distance L2 or distance L3, or a distance farther from the distance measuring device 100 than distance L4.

Figure 7 is a process flow showing the distance measurement method of the distance measuring device 100. As shown in Figure 7, the control unit 30 causes the light projecting units 10a and 10b to simultaneously emit the irradiation light EL2 (step S01). In other words, the distance measuring device 100 causes the light projecting units 10a and 10b to simultaneously emit the irradiation light EL2. Specifically, the control unit 30 causes the light source 11 of each of the light projecting units 10a and 10b to emit the pulsed light EL1. The control unit 30 deflects the pulsed light EL1 by the optical deflection element 12 of each of the light projecting units 10a and 10b. As a result, the irradiation light EL2 is simultaneously emitted from each of the light projecting units 10a and 10b.

Next, the control unit 30 causes the light receiving unit 20 to receive the reflected light RL, which is the irradiation light EL2 reflected by the object OB (step S02). In other words, the distance measuring device 100 receives the reflected light RL with an instantaneous field of view (iFOV) at the light receiving unit 20. Specifically, the control unit 30 deflects the reflected light RL by the optical deflection element 21 of the light receiving unit 20, and causes the deflected reflected light RL to be received by the light receiving element 22.

The control unit 30 measures the distance to the object OB based on the pulsed light EL1 and the reflected light RL (step S03). In other words, the distance measuring device 100 measures the distance to the object OB based on the pulsed light EL1 and the reflected light RL.

Specifically, the control unit 30 acquires the emission time of one pulse of light emitted by the light source 11 and the reception time at which the one pulse of light is detected as reflected light RL by the light receiving element 22. The control unit 30 calculates the distance between the distance measuring device 100 and the object OB based on the time difference between the emission time and the reception time.

As described above, the intensity of each of the emitted lights EL emitted from the light receiving unit 20 and the light emitting units 10a and 10b meets the safety standards at the position of distance L1.

In addition, at distance L2 and beyond, which is farther from distance L1 than distance L1 from the distance measuring device 100, the instantaneous irradiation fields (iFOI(a), iFOI(b)) of the light projectors 10a and 10b are arranged within the instantaneous field of view (iFOV). As the distance from the distance measuring device 100 increases, the proportion of the area of the instantaneous irradiation fields (iFOI(a), iFOI(b)) arranged within the instantaneous field of view (iFOV) increases. Therefore, according to the distance measuring device 100 of this embodiment, it is possible to accurately measure the distance to a distant object OB while complying with safety standards regarding the output of laser light.

The information processing performed by the distance measuring device 100 of the present invention can be executed by a program that executes the information processing performed by the distance measuring device 100 in the above embodiment. The program that executes the information processing method of the present invention can be recorded on a computer-readable recording medium and used suitably. For example, the distance measuring device 100 of the present invention can read the program of the present invention from the recording medium and execute the program of the present invention.

The arrangement of the light-projecting units 10a, 10b is not limited to the arrangement example of this embodiment. For example, as shown in FIG. 8, the light-projecting units 10a, 10b may be arranged in a row on the substrate 40 in a direction perpendicular to the arrangement direction of the light-projecting units 10a, 10b shown in FIG. 4 on the substrate 40.

When the light-projecting units 10a and 10b are arranged in this manner, as described in FIG. 4, it is preferable that the light-projecting units 10a and 10b are arranged at equal distances to the light-receiving unit 20. Specifically, it is preferable that the distance LV1 from the light-receiving unit 20 to the light-projecting unit 10a is equal to the distance LV2 from the light-receiving unit 20 to the light-projecting unit 10b.

Furthermore, the instantaneous irradiation field (iFOI(a), iFOI(b)) may be adjusted by blocking the irradiation light EL2 emitted from the light source 11. Figure 9 shows an example configuration in which a blocking member SC is provided on the light projecting units 10a and 10b. As shown in Figure 9, the blocking member SC is provided between the light source 11 and the light deflection element 12. The blocking member SC blocks a portion of the pulsed light EL1. Therefore, the pulsed light EL1 is partially blocked by the blocking member SC and enters the light reflecting surface MR of the light deflection element 12.

By adjusting the instantaneous irradiation field (iFOI(a), iFOI(b)) with the shielding member SC, it becomes easy to set the output of the light source 11 that emits the irradiation light EL2. For example, when cutting half of the pulsed light EL1 emitted from the light source 11, this can be achieved by shielding half of the pulsed light EL1 with the shielding member SC. Therefore, it becomes easy to set the power of the light source 11 that emits pulsed light with a simple configuration without requiring a configuration to control the current supplied to the light source 11.

In the first embodiment, the light receiving unit 20 is configured to function as a light receiving unit. However, the light receiving unit may be configured to function not only as a light receiving unit but also as a light projecting unit. Note that the same components as those in the distance measuring device 100 of the first embodiment are denoted by the same reference numerals and will not be described.

Figure 10 shows the functional blocks of the distance measuring device 100 according to the second embodiment. As shown in Figure 10, the light source 51 of the light projecting/receiving unit 50 is a light emitting device that emits emitted light. The light source 51 has the same configuration as the light source 11 of the light projecting units 10a and 10b.

The optical deflection element 52 is a device that deflects a light beam in response to a control signal. In other words, the optical deflection element 52 can variably deflect the direction of the pulsed light EL1 and the direction of the reflected light RL. The optical deflection element 52 has an output light reflecting member that includes a light reflecting surface (not shown).

The optical deflection element 52 can be a MEMS mirror device or the like, similar to the optical deflection element 12. The optical deflection element 52 can reflect pulsed light at its light reflecting surface and emit irradiation light EL2 toward the scanning target region R, and can deflect the reflected light toward the light receiving element 53. Therefore, the optical deflection element 52 functions as an emitted light polarizing element and a reflected light polarizing element.

In addition, it is advisable to provide a beam splitter (not shown) between the light source 51 and the optical deflection element 52 to separate the pulsed light EL1 and the reflected light RL.

The light receiving element 53 receives the reflected light RL deflected by the light deflection element 52 and generates a light receiving signal, which is an electrical signal. For example, an avalanche photodiode or the like can be used as the light receiving element 53.

In this way, the light projecting and receiving unit 50 has the functions of a light projecting unit and a light receiving unit. Therefore, the axis AX1 of the instantaneous field of interest (iFOI) of the light projecting and receiving unit 50 coincides with the axis AX2 of the instantaneous field of view (iFOV).

As described above, the distance measuring device 100 of this embodiment, like the distance measuring device 100 of embodiment 1, complies with safety standards regarding the output of laser light and can accurately measure the distance to a distant object OB. In addition, since the axis AX1 of the instantaneous field of view (iFOI) of the light projecting and receiving unit 50 coincides with the axis AX2 of the instantaneous field of view (iFOV), it is possible to accurately measure the distance to the object OB even if the object OB is located at a distance from the distance measuring device 100 that is shorter than the distance L2.

In the distance measuring device 100 according to the first embodiment, the light projecting unit 10a and the light projecting unit 10b are arranged at different positions in the instantaneous field of view (iFOV). However, the light projecting unit 10a and the light projecting unit 10b may be arranged at positions where they overlap each other in the instantaneous field of view (iFOV). Note that the same components as those in the distance measuring device 100 according to the first embodiment are given the same reference numerals and will not be described.

Figure 11 shows an example of the arrangement of the light-projecting unit 10 and the light-receiving unit 20 of the distance measuring device 100 according to the third embodiment. As shown in Figure 11, the light-projecting units 10a to 10d are arranged in a row on the substrate 40 so as to sandwich the light-receiving unit 20. Specifically, the light-projecting units 10a to 10d are arranged such that the light-projecting unit 10a and the light-projecting unit 10d are arranged at the ends of the row, and the light-projecting units 10b and 10c are arranged between them. The light-receiving unit 20 is arranged between the light-projecting units 10b and 10c.

The distance between light-projecting unit 10a and light-projecting unit 10b, the distance between light-projecting unit 10b and light-receiving unit 20, the distance between light-receiving unit 20 and light-projecting unit 10c, and the distance between light-projecting unit 10c and light-projecting unit 10d are all equal.

Figure 12 shows the instantaneous irradiation field (iFOI(a)-iFOI(d)) and the instantaneous field of view (iFOV) on the irradiation surface VS located at a distance L4. Note that the instantaneous irradiation field (iFOI(a)-iFOI(d)) and the instantaneous field of view (iFOV) on the irradiation surface VS are shown in a rectangular shape.

As shown in FIG. 12, in the irradiation surface VS located at a distance L4, the irradiation area RI is formed by the instantaneous irradiation fields (iFOI(a) to iFOI(d)) of each of the light projectors 10a to 10d.

Specifically, the illumination area RI is the area on the illumination surface VS that is illuminated by each of the light projectors 10a to 10d. The illumination area RI includes the entire viewing area RV.

The instantaneous irradiation fields (iFOI(a), iFOI(b)) on the irradiation surface VS of each of a pair of light projectors 10a, 10b among light projectors 10a-10d overlap with each other on the instantaneous visual field (iFOV) on the irradiation surface VS. In addition, the instantaneous irradiation fields (iFOI(c), iFOI(d)) on the irradiation surface VS of each of a pair of light projectors 10c, 10d among light projectors 10a-10d overlap with each other at a distance L4 on the instantaneous visual field (iFOV) on the irradiation surface VS.

The visual field RV is formed by the instantaneous field of view (iFOV) of the light receiving unit 20 at the irradiation surface VS located at the distance L4. The irradiation area RI includes the entire visual field RV at the irradiation surface VS located at the distance L4.

Here, the sum of the intensities of the emitted light EL emitted from each of the light projecting units 10a to 10d that is irradiated within the instantaneous field of view (iFOV) at a distance from the distance measuring device 100 is defined as the irradiated light intensity at the distance from the distance measuring device 100.

In this way, the instantaneous irradiation fields (iFOI(a), iFOI(b)) on the irradiation surface VS of each of the light projectors 10a and 10b overlap each other on the instantaneous field of view (iFOV) on the irradiation surface VS, so that the irradiation light intensity can be increased in the area where the instantaneous irradiation fields (iFOI(a), iFOI(b)) overlap each other. Similarly, the instantaneous irradiation fields (iFOI(c), iFOI(d)) on the irradiation surface VS of each of the light projectors 10c and 10d overlap each other on the instantaneous field of view (iFOV) on the irradiation surface VS, so that the irradiation light intensity can be increased in the area where the instantaneous irradiation fields (iFOI(c), iFOI(d)) overlap each other. Therefore, it is possible to increase the amount of reflected light RL received by the light receiving unit 20.

As described above, the distance measuring device 100 of this embodiment, like the distance measuring device 100 of embodiment 1, complies with safety standards regarding the output of laser light and can accurately measure the distance to a distant object OB. In particular, it is possible to increase the amount of reflected light RL received by the light receiving unit 20, making it possible to accurately measure the distance to the object OB.

The arrangement of the light-projecting units 10a, 10b is not limited to the arrangement example of this embodiment. For example, as shown in FIG. 13, the light-projecting units 10a to 10d may be arranged in a row on the substrate 40 in a direction perpendicular to the arrangement direction of the light-projecting units 10a to 10d shown in FIG. 11.

When light-projecting units 10a to 10d are arranged in this manner, as described in FIG. 11, it is preferable that the distance between light-projecting unit 10a and light-projecting unit 10b, the distance between light-projecting unit 10b and light-receiving unit 20, the distance between light-receiving unit 20 and light-projecting unit 10c, and the distance between light-projecting unit 10c and light-projecting unit 10d are all equal.

Furthermore, the light-projecting units 10a to 10d may each be arranged at an equal distance from the light-receiving unit 20 on the substrate 40. FIG. 14 shows an example of the arrangement of the light-projecting units of a distance measuring device 100 according to a modified example. As shown in FIG. 14, the distance LH1 from the light-receiving unit 20 to the light-projecting unit 10a is equal to the distance LH2 from the light-receiving unit 20 to the light-projecting unit 10c. Furthermore, the distance LV1 from the light-receiving unit 20 to the light-projecting unit 10b is equal to the distance LV2 from the light-receiving unit 20 to the light-projecting unit 10d. Furthermore, the distances LV1, LV2, LH1, and LH2 are equal to one another.

The light receiving unit 20 in this embodiment may be implemented by the light projecting and receiving unit 50 described in embodiment 2.

100 Distance measuring device 10a to 10d Light projecting unit 11 Light source 12 Light deflection element 20 Light projecting and receiving unit 21 Light source 22 Light receiving element 23 Light deflection element 30 Control unit 40 Distance measuring unit iFOI Instantaneous irradiation field iFOV Instantaneous field of view OB Object VS Irradiation surface

Claims (10)

A plurality of light projecting units each including a light source that emits an emission light, and each emitting the emission light as an emission light having an instantaneous irradiation field;
A light receiving unit including a light receiving element that receives light reflected by an object from the irradiated light, and the solid angle of an instantaneous field of view is larger than the solid angle of the instantaneous irradiation field of each of the irradiated lights;
having
An optical device characterized in that, on an irradiation surface located a predetermined distance from the light receiving unit, an irradiation area formed by the instantaneous irradiation fields of the multiple light projecting units includes a field of view formed by the instantaneous field of view. The optical device according to claim 1, characterized in that each of the light projecting units includes an output light deflection element that deflects the output light in a variable direction, and each of the light projecting units emits the output light deflected by the output light deflection element as irradiation light having an instantaneous irradiation field. The optical device according to claim 2, characterized in that the light projecting unit has a shielding member between the light source and the emitted light deflection element that shields a portion of the emitted light. An optical device according to any one of claims 1 to 3, characterized in that the instantaneous irradiation fields of at least one set of the plurality of light-projecting units overlap each other at a predetermined distance from the light-receiving unit on the instantaneous visual field. The plurality of light projecting units include four light projecting units,
5. The optical device according to claim 1, wherein, on an irradiation surface at a predetermined distance from the light receiving unit, the instantaneous irradiation fields of the irradiation light emitted from two of the plurality of light projecting units overlap with each other to form one irradiation area, and the instantaneous irradiation fields of the irradiation light emitted from two of the plurality of light projecting units other than the two light projecting units overlap with each other to form another irradiation area. An optical device according to any one of claims 1 to 5, characterized in that the axis of the instantaneous irradiation field of one of the multiple light projecting units coincides with the axis of the instantaneous visual field. an optical device comprising: a plurality of light projecting units each including a light source for emitting an emission light, and each emitting the emission light as an illumination light having an instantaneous illumination field; and a light receiving unit including a light receiving element for receiving a reflected light of the illumination light reflected by an object, and having a solid angle of an instantaneous visual field larger than a solid angle of the instantaneous illumination field of each of the illumination lights, wherein, on an illumination surface at a predetermined distance from the light receiving unit, an illumination area formed by the instantaneous illumination fields of the plurality of light projecting units includes a visual field area formed by the instantaneous visual field;
a distance measuring unit that measures a distance to the object based on the emitted light and the reflected light;
A distance measuring device comprising: a light-projecting unit including a light source for emitting an emission light and for emitting the emission light as an emission light having an instantaneous illumination field; and a light-receiving unit including a light-receiving element for receiving light reflected from an object from the emission light and having a solid angle of an instantaneous visual field larger than a solid angle of the instantaneous illumination field of each of the emission lights, wherein an illumination area formed by the instantaneous illumination fields of the light-projecting units on an illumination surface at a predetermined distance from the light-receiving unit includes a visual field area formed by the instantaneous visual field; and a distance measuring unit for measuring a distance to the object based on the emission light and the reflected light,
a step of simultaneously emitting the irradiation light from each of the plurality of light projecting units;
receiving the reflected light with the light receiving unit at the instantaneous field of view;
measuring a distance to the object based on the emitted light and the reflected light;
A distance measuring method comprising: a light-projecting unit including a light source for emitting an emission light and for emitting the emission light as an emission light having an instantaneous illumination field; and a light-receiving unit including a light-receiving element for receiving light reflected from an object from the emission light and having a solid angle of an instantaneous visual field larger than a solid angle of the instantaneous illumination field of each of the emission lights, wherein an illumination area formed by the instantaneous illumination fields of the light-projecting units on an illumination surface at a predetermined distance from the light-receiving unit includes a visual field area formed by the instantaneous visual field; and a distance measuring unit for measuring a distance to the object based on the emission light and the reflected light,
a step of simultaneously emitting the irradiation light from each of the plurality of light projecting units;
receiving the reflected light with the light receiving unit at the instantaneous field of view;
measuring a distance to the object based on the emitted light and the reflected light;
A program for causing a computer to execute the above steps. a light-projecting unit including a light source for emitting an emission light and for emitting the emission light as an emission light having an instantaneous illumination field; and a light-receiving unit including a light-receiving element for receiving light reflected from an object from the emission light and having a solid angle of an instantaneous visual field larger than a solid angle of the instantaneous illumination field of each of the emission lights, wherein an illumination area formed by the instantaneous illumination fields of the light-projecting units on an illumination surface at a predetermined distance from the light-receiving unit includes a visual field area formed by the instantaneous visual field; and a distance measuring unit for measuring a distance to the object based on the emission light and the reflected light,
a step of simultaneously emitting the irradiation light from each of the plurality of light projecting units;
receiving the reflected light with the light receiving unit at the instantaneous field of view;
measuring a distance to the object based on the emitted light and the reflected light;
A recording medium having a program recorded thereon for causing a computer to execute the above-mentioned operation.

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