JP2024100370A - Measurement device, and measurement system - Google Patents

Abstract

To improve spatial resolving power of imaging.SOLUTION: A measurement device comprises: at least two or more laser modules that have a light emission element emitting phase-modulated laser light to an object, and a light reception element receiving the laser light reflected by the object, and are arranged in a mutually separated location; and a computation unit that synthesizes light reception signals of the laser light received by respective light reception elements of the laser modules by correcting a phase difference, and thus, derives an imaging effect of a surface of the object.SELECTED DRAWING: Figure 1

Description

This disclosure relates to a measurement device and a measurement system.

In recent years, there has been a demand for improved spatial resolution in CMOS image sensors installed in smartphones and digital cameras.

In order to improve the spatial resolution of CMOS image sensors, it is important to miniaturize the sensor pixels, but miniaturizing the sensor pixels leads to a decrease in the saturation charge of the sensor pixels and an increase in color mixing between the sensor pixels. For this reason, the development of technology to improve the spatial resolution of CMOS image sensors is becoming more difficult every year.

However, since light is also an electromagnetic wave, it is known to cause diffraction and interference. Therefore, electromagnetic interferometers used in space observations and other such purposes exploit the coherence of light to achieve high-resolution observation of outer space. Specifically, electromagnetic interferometers receive electromagnetic waves from outer space at multiple different locations, and by causing the received electromagnetic waves to interfere with each other with zero phase difference, they are able to observe outer space with high resolution.

The electromagnetic waves received from outer space can be easily made to interfere because the distance from space to the Earth is very long and they can be considered to be almost plane waves. However, sunlight and other light that normally propagates through space has a random phase, making it difficult to make them interfere as is. For example, the following Patent Document 1 discloses a technology in which laser light with a uniform wavelength and phase is emitted to an object, and the laser light reflected by the object is received, thereby obtaining interference fringes of the received laser light.

JP 2018-93085 A

In view of the above, it is desirable to improve the spatial resolution of imaging by receiving reflected light of laser light emitted to an object and synthesizing the received reflected light after correcting the phase difference.

According to the present disclosure, there is provided a measurement device comprising at least two or more laser modules having a light-projecting element that emits phase-modulated laser light to an object and a light-receiving element that receives the laser light reflected by the object, the laser modules being disposed at positions spaced apart from each other, and a calculation unit that derives an imaging result of the surface of the object by correcting the phase difference and combining the received light signals of the laser light received by the light-receiving elements of each of the laser modules.

The present disclosure also provides a measurement system including at least two laser modules that have a light-projecting element that emits phase-modulated laser light to an object and a light-receiving element that receives the laser light reflected by the object and are disposed at positions spaced apart from each other, and a calculation unit that derives an imaging result of the surface of the object by correcting the phase difference and combining the light-receiving signals of the laser light received by the light-receiving elements of each of the laser modules.

FIG. 1 is a schematic perspective view showing a configuration of a measurement device according to an embodiment of the present disclosure. 10 is an explanatory diagram showing how a distance measuring sensor measures the distance between a main body and an object. FIG. 10 is an explanatory diagram showing how laser light is emitted from each laser module to a measurement point and how the reflected laser light is received by each laser module. FIG. FIG. 2 is a block diagram showing the internal configuration of a measurement device. FIG. 2 is a schematic diagram showing a combination of a plurality of laser modules. FIG. 4 is a flowchart showing the flow of a first operation example of the measurement device. FIG. 11 is a flowchart showing the flow of a second operation example of the measurement device. 1 is a schematic perspective view showing an example of the arrangement and movement direction of a laser module; 1 is a schematic perspective view showing an example of the arrangement and movement direction of a laser module; FIG. 13 is a block diagram showing a modified example of the internal configuration of the measurement device. FIG. 1 is a schematic diagram showing an example of a humanoid robot equipped with a measuring device. FIG. 1 is a schematic diagram showing an example of a pet-type robot equipped with a measuring device. FIG. 1 is a schematic diagram showing an example of a moving body on which a measuring device is mounted. FIG. 1 is a schematic perspective view showing an overview of a measurement device configured as a portable detection device. FIG. 1 is a schematic perspective view showing an overview of a measurement device configured as a stationary detection device. FIG. 2 is a longitudinal sectional view showing a cross-sectional configuration of a measuring device that causes a pixel to function as a laser module. FIG. 1 is a top view showing a planar configuration of a measuring device that causes a pixel to function as a laser module.

A preferred embodiment of the present disclosure will be described in detail below with reference to the attached drawings. Note that in this specification and drawings, components having substantially the same functional configuration are designated by the same reference numerals to avoid redundant description.

The explanation will be given in the following order.
1. Configuration of the Measuring Apparatus 2. Operation of the Measuring Apparatus 3. Modifications

1. Configuration of the measuring device
First, the configuration of a measurement device according to an embodiment of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a schematic perspective view showing the configuration of a measurement device 10 according to the present embodiment.

As shown in FIG. 1, the measuring device 10 includes a main body 100, a distance sensor 120, and a number of laser modules 110A, 110B, 110C, and 110D (collectively referred to as laser modules 110 when not distinguished from one another).

The main body 100 corresponds to the main body of the measuring device 10, and supports the distance measurement sensor 120 and the multiple laser modules 110. Specifically, the main body 100 may be configured as a flat housing. The main body 100 may also be equipped with a control device that controls the overall operation of the measuring device 10, a power supply device that supplies power to each part of the measuring device 10, and the like. For example, the main body 100 may be equipped with a power supply circuit that supplies power to the distance measurement sensor 120 and the multiple laser modules 110, a logic circuit that controls each of the distance measurement sensor 120 and the multiple laser modules 110, and an arithmetic circuit that calculates the sensing results obtained by the distance measurement sensor 120 and the multiple laser modules 110.

The multiple laser modules 110 are provided at a distance from each other on one main surface of a flat-plate-shaped housing that constitutes the main body 100. Specifically, the multiple laser modules 110 may be provided at positions corresponding to each vertex of a polygon (rectangle in FIG. 1) on one main surface of the main body 100. For example, when the main body 100 is configured as a rectangular flat-plate-shaped housing, the multiple laser modules 110 may be provided at each of the four corners of one main surface of the main body 100.

The multiple laser modules 110 are also provided so as to be movable in a predetermined direction so that the distance between them can be changed. For example, the multiple laser modules 110 may be provided so as to be movable on the diagonals of a polygon (a rectangle in FIG. 1) having the multiple laser modules 110 as vertices. The movement of the multiple laser modules 110 may be performed, for example, by MEMS (Micro Electro Mechanical Systems).

The multiple laser modules 110 are modules each having a light-emitting element 111 and a light-receiving element 112.

The light-projecting element 111 is a semiconductor laser element that emits phase-modulated laser light. The light-projecting element 111 may be, for example, a blue semiconductor laser or an infrared semiconductor laser. The emission angle of the laser light emitted from the light-projecting element 111 may be controlled, for example, by a MEMS mirror.

The light receiving element 112 is a photodiode that receives the laser light emitted from the light projecting element 111 and reflected by the object to be measured. The laser modules 110 can receive the laser light emitted from their own light projecting elements 111 and reflected by the object with the light receiving element 112. The light receiving element 112 may be, for example, a silicon photodiode, a compound semiconductor (InGaAs, etc.) photodiode, or a SPAD (Single Photon Avalanche Diode). In addition, a bandpass filter that selectively transmits a wavelength band including the wavelength of the laser light emitted from the light projecting element 111 may be provided on the light receiving surface of the light receiving element 112.

The laser light received by the light receiving element 112 reflects the surface condition of the object, so the measuring device 10 can derive information about the object's surface from the intensity and phase of the received laser light. In addition, the measuring device 10 can derive information about the surface distribution of the object with higher accuracy and resolution by combining the laser light received by each of the multiple laser modules 110 so as to reinforce each other.

However, in the multiple laser modules 110, reflected light of laser light emitted from light-projecting elements 111 other than the laser module's own light-projecting element 111, and other natural light, may be received by the light-receiving element 112, resulting in measurement noise. For this reason, the multiple laser modules 110 may measure in advance the received light intensity when laser light is emitted only from light-projecting elements 111 other than the laser module's own light-projecting element 111, and subtract the received light intensity from the measurement result as background noise. In this way, the multiple laser modules 110 can measure the reflected light of laser light emitted from their own light-projecting elements 111 with higher accuracy by subtracting the background noise measured in advance from the measurement result.

The distance measurement sensor 120 is provided on the same main surface of the main body 100 on which the multiple laser modules 110 are provided. Specifically, the distance measurement sensor 120 may be provided at a position corresponding to the center of gravity of a polygon (a rectangle in FIG. 1 ) whose vertices are the multiple laser modules 110.

The distance measurement sensor 120 is a sensor that measures the distance between the main body 100 and an object. For example, the distance measurement sensor 120 may be a ToF (Time of Flight) sensor that uses a Vertical Cavity Surface Emitting Laser (VCSEL). The distance measurement sensor 120 can measure the distance between surfaces by using a VCSEL as the light source of the ToF sensor. This allows the distance measurement sensor 120 to obtain distance information with higher accuracy. The distance between the main body 100 and the object measured by the distance measurement sensor 120 is used, for example, to determine the angle at which laser light is emitted from the light-emitting elements 111 of the multiple laser modules 110.

With such a measuring device 10, the imaging results of the surface of the object can be derived by the following method. The principle of measurement by the measuring device 10 will be described with reference to Figures 2 and 3. Figure 2 is an explanatory diagram showing how the distance between the main body 100 and the object 30 is measured by the distance measuring sensor 120. Figure 3 is an explanatory diagram showing how each of the laser modules 110 emits laser light to the measurement point 20 and how the laser light reflected at the measurement point 20 is received by each of the laser modules 110.

First, as shown in FIG. 2, the distance measurement sensor 120 measures the distance L between the object 30 to be measured and the main body 100. Specifically, the distance measurement sensor 120 measures the distance L between the main body 100 and the object 30 by measuring the time it takes for light irradiated to the object 30 to be reflected by the object 30 and return (using the so-called ToF method).

Next, as shown in FIG. 3, laser modules 110A and 110B each emit a phase-modulated laser beam in synchronization with each other toward measurement point 20 on object 30. Measurement point 20 is selected so that the angle θ between a line extending from the midpoint between laser modules 110A and 110B in the normal direction to the main surface of main body 100 and a line connecting the midpoint and measurement point 20 is smaller than 1 degree.

The laser light emitted to the measurement point 20 of the target object 30 is reflected at the measurement point 20 and received by the laser modules 110A and 110B that emitted the laser light. When the phase difference between the measurement values V ₁ (t) and V 2 (t) of the light receiving elements 112 of the laser modules 110A and 110B is corrected using the delay time τ _g between the laser modules 110A and 110B, the measurement values V 1 (t) and V ₂ (t) are expressed by, for example, the following formulas 1 and 2.

In Equation 1 and Equation 2, e ₁ and e ₂ represent the intensities of the laser beams received by the laser modules 110A and 110B, respectively, and the exp portion represents the phase portion of the laser beam. In addition, t represents time, and ν represents the frequency. The delay time τ _g for correcting the phase difference of the laser beams received by the laser modules 110A and 110B can be expressed as τ _g =2D·(tan θ)/c using the distance D between the laser modules 110A and 110B and the above-mentioned angle θ. The correction of the phase difference by the delay time τ _g is performed to combine the laser beams received by the laser modules 110A and 110B so as to reinforce each other.

Furthermore, by taking the product of _V1 (t) and _V2 (t) described above, the correlation function _r12 (D) of the laser modules 110A and 110B can be derived. By deriving the correlation function _r12 (D), the measurement values _V1 (t) and _V2 (t) of the light receiving elements 112 of the laser modules 110A and 110B are combined with each other. The derived correlation function _r12 (D) is shown in the following formula 3. λ is the wavelength of the laser light emitted from the laser modules 110A and 110B. In addition, since θ<1°, it is possible to approximate tan θ=θ.

The intensities _e1 and _e2 of the laser beams received by the laser modules 110A and 110B, respectively, are affected by scattering or attenuation due to the surface distribution of the object 30 at the measurement point 20. If the surface distribution of the object 30 at the measurement point 20 is F(θ), then by performing an inverse Fourier transform on Equation 3, the surface distribution F(θ) of the object 30 at the measurement point 20 can be derived as shown in Equation 4 below, where _Dλ =D/λ.

The surface distribution F(θ) of the object 30 is considered to be a function of the surface shape of the object 30, so the measurement device 10 is able to image the surface of the object 30 by deriving the surface distribution F(θ).

In the above formula 4, the surface distribution F(θ) of the object 30 is derived by integration with respect to D _λ , and therefore the resolution of the surface distribution F(θ) of the object 30 is λ/D, which is the inverse of D _λ . For example, when the light-projecting elements 111 of the laser modules 110A and 110B are blue semiconductor laser elements that emit blue laser light with a wavelength of 450 nm, and the distance between the laser modules 110A and 110B is 15 cm (λ=450 nm, D=15 cm), the measurement device 10 can ideally measure the surface distribution F(θ) of the object 30 with a resolution of 150 nm.

As described above, the laser modules 110A and 110B are arranged so that the distance D between them is variable. Therefore, the measuring device 10 can control the resolution for the object 30 to be measured by controlling the distance D between the laser modules 110A and 110B.

Furthermore, the internal configuration of the measurement device 10 according to this embodiment will be described with reference to Figs. 4 and 5. Fig. 4 is a block diagram showing the internal configuration of the measurement device 10 according to this embodiment. Fig. 5 is a schematic diagram showing a combination of multiple laser modules 110A, 110B, 110C, and 110D used for measurement.

As shown in FIG. 4, the measuring device 10 has, as its functional configuration, a distance measurement sensor 120, a plurality of laser modules 110 each having a light-emitting element 111 and a light-receiving element 112, a control unit 131, and a calculation unit 132. The distance measurement sensor 120 and the plurality of laser modules 110 have been described with reference to FIG. 1, and therefore will not be described here.

The control unit 131 is a logic circuit that controls the emission of laser light from each of the light-projecting elements 111 of the multiple laser modules 110. The control unit 131 may control the phase of the laser light emitted from each of the light-projecting elements 111 of the multiple laser modules 110 and the emission timing of the laser light. For example, the control unit 131 may control each of the light-projecting elements 111 of the multiple laser modules 110 so as to emit synchronously phase-modulated laser light at the same measurement point in a timed manner.

The control unit 131 may also set a measurement point 20 at which laser light is emitted from each of the light-emitting elements 111 of the multiple laser modules 110 based on the distance between the main body unit 100 and the target object 30 measured by the distance measurement sensor 120. For example, the control unit 131 may set the measurement point 20 so that the angle from a straight line that passes through the midpoint between the multiple laser modules 110 that emit laser light and extends in the normal direction of the main surface of the main body unit 100 is less than 1 degree.

The calculation unit 132 is a calculation circuit that derives the surface distribution of the object 30 at the measurement point 20 based on the measured values of the laser light received by the light receiving elements 112 of each of the multiple laser modules 110. As described above, the calculation unit 132 may derive the surface distribution of the object 30 at the measurement point 20 by phase-correcting and synthesizing the laser light received by the light receiving elements 112 of each of the multiple laser modules 110 and performing an inverse Fourier transform.

Furthermore, the control unit 131 and the calculation unit 132 may derive a surface distribution of the target 30 over a wider range by changing the measurement point 20 from which the laser light is emitted. At this time, the combination of the laser modules 110 that emit the laser light to the measurement point 20 may be changed for each measurement point 20. Specifically, first, the control unit 131 selects the measurement point 20 from which the laser light is emitted. Next, the control unit 131 selects a combination of the laser modules 110 that emit the laser light to the measurement point 20, and controls the emission angle, phase modulation, and emission timing of the laser light emitted from the light-projecting element 111 of the laser module 110 of the selected combination. After that, the calculation unit 132 corrects the phase of the laser light reflected at the measurement point 20 and then received by the light-receiving element 112 of the laser module 110, synthesizes it, and performs an inverse Fourier transform to derive the surface distribution of the target 30 at the measurement point 20. The control unit 131 and the calculation unit 132 can map the surface distribution of the object 30 over a wider range by sequentially measuring the surface distribution of the object 30 while changing the measurement point 20.

As shown in FIG. 5, when the measuring device 10 has four laser modules 110A, 110B, 110C, and 110D, the control unit 131 and the calculation unit 132 can derive six correlation functions r ₁₂ , r ₁₃ , r ₂₃ , r ₁₄ , r ₂₄ , and r ₃₄ by selecting a combination of two laser modules from the four laser modules 110A, 110B, 110C, and 110D.

At this time, the measurement device 10 can simultaneously perform measurements using the laser modules 110A and 110B (correlation function r ₁₂ ) and measurements using the laser modules 110C and 110D (correlation function r ₃₄ ). Similarly, the measurement device 10 can simultaneously perform measurements using the laser modules 110A and 110C (correlation function r ₁₃ ) and measurements using the laser modules 110B and 110D (correlation function r ₂₄ ). Furthermore, the measurement device 10 can simultaneously perform measurements using the laser modules 110B and 110C (correlation function r ₂₃ ) and measurements using the laser modules 110A and 110D (correlation function r ₁₄ ).

In other words, when the measuring device 10 is equipped with N laser modules 110, it can derive the surface distribution of N×(N-1)/2 measurement points 20 with N×(N-1)/4 measurements. This allows the measuring device 10 to derive imaging results for a wider range of the object 30 by mapping the derived surface distribution of the measurement points 20. Furthermore, by being equipped with more laser modules 110, the measuring device 10 can derive imaging results for a wider range of the object 30 at higher speed.

2. Operation of the Measuring Device
Next, the operation of the measurement device 10 according to the present embodiment will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is a flow chart showing the flow of a first operation example of the measurement device 10 according to the present embodiment. Fig. 7 is a flow chart showing the flow of a second operation example of the measurement device 10 according to the present embodiment.

(First operation example)
The first operation example is an operation example in which the angle at which the laser light is emitted from the measurement device 10 is changed, thereby changing the measurement point 20 at which the laser light is emitted on the surface of the target object 30 .

As shown in FIG. 6, first, the measuring device 10 moves each of the laser modules 110 in accordance with the resolution set by the user (S101). Specifically, the measuring device 10 moves each of the laser modules 110 to vary the distance between each of the laser modules 110 so as to achieve the resolution set by the user.

Next, the measuring device 10 measures the vertical distance to the object 30 (S102). For example, the measuring device 10 may use a ToF distance measuring sensor 120 to measure the distance between the main body 100 and the object 30 in a direction perpendicular to the main surface of the main body 100.

Next, the measuring device 10 sets the angle θ at which the laser light is emitted from the laser module 110 (S103). Specifically, the measuring device 10 uses the distance between the main body 100 and the target object 30 to set the measuring point 20 and the angle θ so that the angle θ from the midpoint between the laser modules 110 that emit the laser light to the measuring point 20 at which the laser light is emitted is less than 1°.

Then, the measuring device 10 performs measurement by emitting laser light from each light-emitting element 111 of the laser module 110 to the measurement point 20 (S104). Next, the measuring device 10 combines the received light signals of the laser light reflected at the measurement point 20 and performs an inverse Fourier transform (inverse FFT) (S105). Specifically, the measuring device 10 receives the laser light reflected at the measurement point 20 with each light-receiving element 112 of the laser module 110, corrects the phase difference, and derives the correlation function of the received light signals. Furthermore, the measuring device 10 performs an inverse Fourier transform on the derived correlation function. This allows the measuring device 10 to derive the surface distribution F(θ) of the object 30 in the θ direction (S106).

Next, the measuring device 10 changes the angle θ at which the laser light is emitted from each of the laser modules 110 by dθ (S107). Specifically, the measuring device 10 changes the angle θ from the midpoint between the laser modules 110 emitting the laser light to the measuring point 20 at which the laser light is emitted by dθ, thereby changing the measuring point 20 at which the laser light is emitted. In addition, the measuring device 10 determines whether the angle θ at which the changed laser light is emitted has reached the maximum value (1°) (S108).

If the angle θ has not reached the maximum value (S108/No), the measuring device 10 executes steps S104 to S107 again to derive the surface distribution F(θ) of the object 30 in the θ direction. On the other hand, if the angle θ has reached the maximum value (S108/Yes), the measuring device 10 maps the derived surface distribution F(θ) of the object 30 to derive the imaging result of the object 30 (S109).

According to the above first operation example, the measurement device 10 can derive an imaging result of the surface of the object 30 by scanning the surface of the object 30 while changing the angle θ at which the laser light is emitted.

(Second operation example)
The second operation example is an operation example in which the user moves the measuring device 10 to change the measurement point 20 at which the laser light is emitted on the surface of the target object 30 .

The operations in steps S201 to S206 shown in FIG. 7 are substantially similar to the operations in steps S101 to S106 shown in FIG. 6, so a description thereof will be omitted here.

After deriving the surface distribution F(θ) of the object 30 in the θ direction (S206), the measuring device 10 determines whether acceleration has been detected (S207). If acceleration has been detected (S207/Yes), the measuring device 10 determines that the user has moved the measuring device 10 along the surface of the object 30, and derives the surface distribution F(θ) of the object 30 in the θ direction by performing the operations of steps S204 to S206 again. Note that the emission angle θ of the laser light at this time may remain the angle θ set in step S203.

On the other hand, if no acceleration is detected (S207/No), the measurement device 10 determines that the user has finished measuring the object 30, and derives the imaging results of the object 30 by mapping the derived surface distribution F(θ) of the object 30 (S208).

According to the second operation example described above, the measurement device 10 can derive imaging results for the surface of the object 30 by fixing the angle θ at which the laser light is emitted and scanning the surface of the object 30 through the user's operation.

3. Modifications
Next, first to seventh modified examples of the measuring device 10 according to the present embodiment will be described below.

(First Modification)
A first modified example will be described with reference to Fig. 8 and Fig. 9. The first modified example is a modified example showing variations in the arrangement and movement direction of the laser module 110 on the main body 100. Fig. 8 and Fig. 9 are schematic perspective views showing an example of the arrangement and movement direction of the laser module 110.

As shown in FIG. 8, the laser modules 110A, 110B, 110C, and 110D may be provided at positions corresponding to the sides of the rectangular main surface of the main body 100. In this case, the laser modules 110A, 110B, 110C, and 110D may be provided so as to be movable in a direction toward the center of the main surface of the main body 100.

As shown in FIG. 9, the laser modules 110A, 110B, 110C, and 110D may be provided at positions corresponding to the four corners of the rectangular main surface of the main body 100. In this case, the laser modules 110A, 110B, 110C, and 110D may be provided movably along each side of the main surface of the main body 100.

However, the direction of movement of the laser modules 110A, 110B, 110C, and 110D is not particularly limited. The direction of movement of the laser modules 110A, 110B, 110C, and 110D may be any of the diagonal directions of the rectangular main surface of the main body 100, the directions in which the sides face each other, the directions along the sides, and the circumferential direction of any circle. The measuring device 10 can dynamically change the resolution of the imaging result of the object 30 by arbitrarily changing the distance between each of the laser modules 110A, 110B, 110C, and 110D.

(Second Modification)
A second modified example will be described with reference to Fig. 10. The second modified example is a modification in which the calculations in the measurement device 10 are performed on a cloud external to the measurement device 10. Fig. 10 is a block diagram showing a modified example of the internal configuration of the measurement device 10.

As shown in FIG. 10, the measurement device 10 may include a communication unit 133 instead of the calculation unit 132 shown in FIG. 4.

The communication unit 133 transmits and receives data to and from the cloud 70 via the network 50. The communication unit 133 may be, for example, a communication interface configured with a communication device for connecting to the network 50. The communication unit 133 may be, for example, a communication card for a wired or wireless LAN (Local Area Network), Wi-Fi (registered trademark), Bluetooth (registered trademark), or WUSB (Wireless USB), or may be a router for optical communication, a router for ADSL (Asymmetric Digital Subscriber Line), or a modem for various types of communication. The network 50 is a network connected by wire or wirelessly, and may be, for example, an Internet communication network, a home LAN, an infrared communication network, a radio wave communication network, or a satellite communication network.

Cloud 70 is a network service consisting of a group of computers with excellent computational processing capabilities. Cloud 70 can, for example, execute the computations executed by computation unit 132 shown in FIG. 4 instead. Specifically, cloud 70 can derive the surface distribution of object 30 at measurement point 20 by synthesizing the phase difference correction of the measured values of the laser light received by light receiving element 112 and transmitted from communication unit 133 and performing an inverse Fourier transform. The derived surface distribution of object 30 at measurement point 20 is transmitted to communication unit 133 of measurement device 10.

As a result, the measuring device 10 can reduce the processing load within the measuring device 10 by having the cloud 70 execute calculations that have a high processing load, such as an inverse Fourier transform.

(Third Modification)
The third modified example is a variation in which the emission angle of the laser light from each light-projecting element 111 of the laser module 110 is fixed.

The measuring device 10 can derive imaging results for the surface of the object 30 even when the emission angle of the laser light from each light-projecting element 111 of the laser module 110 is fixed. For example, the measuring device 10 can irradiate the same measurement point 20 with the laser light emitted from each light-projecting element 111 of the laser module 110 by specifying the distance between the main body 100 and the object 30 during measurement. In this way, the measuring device 10 can similarly derive the surface distribution of the object 30 at the measurement point 20.

(Fourth Modification)
A fourth modified example will be described with reference to Figures 11 to 13. The fourth modified example is a variation in which the measuring device 10 is mounted on a robot. Figure 11 is a schematic diagram showing an example of a humanoid robot 1 equipped with the measuring device 10. Figure 12 is a schematic diagram showing an example of a pet-type robot 2 equipped with the measuring device 10. Figure 13 is a schematic diagram showing an example of a moving object 3 equipped with the measuring device 10.

As shown in FIG. 11, in the humanoid robot 1, the measuring device 10 may obtain an imaging result of the environment around the humanoid robot 1 by emitting and receiving laser light with a laser module 110 provided at a position corresponding to the eyes on the head of the humanoid robot 1. As shown in FIG. 12, in the pet robot 2, the measuring device 10 may obtain an imaging result of the environment around the pet robot 2 by emitting and receiving laser light with a laser module 110 provided at a position corresponding to the eyes on the head of the pet robot 2. As shown in FIG. 13, in the moving body 3, the measuring device 10 may obtain an imaging result of the environment around the moving body 3 by emitting and receiving laser light with a laser module 110 provided at a predetermined interval around the entire circumference of the side of the moving body 3. The moving body 3 is, for example, a robot vacuum cleaner that collects dirt and the like in the area it travels.

By mounting the measuring device 10 on these robots (humanoid robot 1, pet robot 2, mobile object 3, etc.), it is possible to obtain imaging results of the environment around the robot. As a result, these robots can determine and control their operations using the imaging results derived by the measuring device 10.

(Fifth Modification)
A fifth modified example will be described with reference to Fig. 14. The fifth modified example is a modified example in which the measuring device 10 is configured as a portable detection device. Fig. 14 is a schematic perspective view showing an overview of a measuring device 10A configured as a portable detection device.

As shown in FIG. 14, the measuring device 10A includes a main body 100 and legs 140A, 140B, 140C, and 140D. As shown in FIG. 1, a plurality of laser modules 110 and a distance measurement sensor 120 are provided on the surface of the main body 100 facing the object 30 (the back surface, not shown). After measuring the distance between the main body 100 and the object 30 with the distance measurement sensor 120, the measuring device 10A can obtain an imaging result of the measurement point 20 by emitting laser light from the plurality of laser modules 110 to the measurement point 20.

The legs 140A, 140B, 140C, and 140D are rod-shaped structural members that can expand and contract in the extension direction. The legs 140A, 140B, 140C, and 140D may be provided, for example, on the side of the main body 100. The legs 140A, 140B, 140C, and 140D can fix the distance between the main body 100 and the object 30 by supporting the main body 100 on the object 30. This allows the measuring device 10A to irradiate the measurement point 20 with laser light emitted from the multiple laser modules 110 with higher accuracy, thereby obtaining a spatial resolution closer to the ideal.

(Sixth Modification)
A sixth modified example will be described with reference to Fig. 15. The sixth modified example is a modified example in which the measuring device 10 is configured as a stationary detection device. Fig. 15 is a schematic perspective view showing an overview of a measuring device 10B configured as a stationary detection device.

As shown in FIG. 15, the measurement device 10B includes a main body 100 having multiple laser modules 110 and a distance measurement sensor 120, and an installation section 150.

The installation unit 150 is a flat structural member. The main body 100 is provided on the surface of the installation unit 150, and a hook, pin, adhesive sheet, or the like is provided on the back surface of the installation unit 150 opposite the surface for attaching the measuring device 10B to a wall or door. The measuring device 10B can be installed indoors to monitor an object 30 present in the room. In addition, the measuring device 10B installed indoors can measure the distance to the object 30 with higher accuracy by using the known distance between the walls of the room as a reference. Therefore, the measuring device 10B can irradiate the object 30 with laser light emitted from the multiple laser modules 110 with higher accuracy, thereby obtaining a spatial resolution closer to the ideal.

(Seventh Modification)
A seventh modified example will be described with reference to Fig. 16 and Fig. 17. The seventh modified example is a modified example in which the pixel Px of the imaging device functions as a laser module 110. Fig. 16 is a vertical cross-sectional view showing a cross-sectional configuration of the measuring device 10C. Fig. 17 is a top view showing a planar configuration of the measuring device 10C.

As shown in FIG. 16, the measuring device 10C includes a semiconductor substrate 170 including a photoelectric conversion section 171 and a pixel separation section 173, an insulating layer 174, a waveguide 161, a diffraction grating 162, and a microlens 163.

The semiconductor substrate 170 is, for example, a silicon substrate. The semiconductor substrate 170 is provided with photoelectric conversion units 171 separated by pixel separation units 173 for each pixel Px. The photoelectric conversion units 171 are photodiodes that convert incident light into electric charges. The photoelectric conversion units 171 are configured by forming a second conductivity type (e.g., n-type) region inside the semiconductor substrate 170 doped to a first conductivity type (e.g., p-type). The pixel separation units 173 are insulating layers provided between the pixels Px, and extend in the thickness direction of the semiconductor substrate 170 to electrically separate the photoelectric conversion units 171 provided in each pixel Px. The pixel separation units 173 may be configured with an insulating material such as silicon dioxide (SiO ₂ ), silicon nitride (SiN _x ), or silicon oxynitride (SiON).

The insulating layer 174 is made of a transparent insulating material, and is provided on the light-receiving surface side of the semiconductor substrate 170. The insulating layer 174 may be made of silicon dioxide (SiO ₂ ), silicon nitride (SiN _x ), silicon oxynitride (SiON), or the like.

The waveguide 161 functions as an optical path that propagates the laser light Lb to each pixel. The waveguide 161 is made of a material having a higher refractive index than the insulating layer 174 and the microlens 163, and the laser light Lb is totally reflected at the boundary surface of the waveguide 161, so that the laser light Lb can be propagated to each pixel Px with almost no loss. The waveguide 161 may be made of a high refractive index material such as aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), or tantalum oxide (Ta ₂ O ₅ ).

For example, as shown in FIG. 17, the waveguide 161 propagates the laser light Lb generated by the light source 181 to each pixel Px. Specifically, the waveguide 161 extends from the light source 181 in the column direction of the pixels Px (vertical direction when facing FIG. 17), and then branches to the pixels Px of each row extending in the row direction (horizontal direction when facing FIG. 17). In this way, the waveguide 161 can propagate the laser light to each pixel Px on a row-by-row basis by controlling the branching of the laser light to the pixels Px of each row with an optical switch 182 such as a Mach-Zehnder.

The diffraction grating 162 is a grating composed of linear projections and recesses extending in a direction perpendicular to the propagation direction of the waveguide 161. The diffraction grating 162 may be composed of the same material as the waveguide 161. The diffraction grating 162 can generate output light Lx and reference light Ld that are output to the outside of the waveguide 161 by scattering the laser light Lb that propagates through the waveguide 161. The output angles of the output light Lx and reference light Ld can be controlled by the wavelength of the laser light Lb and the pitch of the diffraction grating 162. It is desirable to control the output angles of the output light Lx and reference light Ld to be less than 1°.

The microlens 163 is a lens that focuses light incident on the measurement device 10C, and is provided for each pixel Px on the waveguide 161. The microlens 163 may be made of an inorganic material such as silicon dioxide (SiO ₂ ), or an organic material such as acrylic resin.

Here, the outgoing light Lx emitted from the waveguide 161 toward the microlens 163 is emitted to the object 30, which is the object to be measured, via the microlens 163. The outgoing light Lx emitted to the object 30 is reflected by the surface of the object 30 to become reflected light Lr. The reflected light Lr interferes with the reference light Ld emitted from the waveguide 161 toward the semiconductor substrate 170, and is then converted into an electric charge by the photoelectric conversion unit 171.

Here, when the phase of the reflected light Lr and the phase of the reference light Ld are aligned, the reflected light Lr and the reference light Ld constructively interfere with each other when passing through the insulating layer 174. Therefore, the photoelectric conversion unit 171 can obtain a charge signal corresponding to the correlation function _r12 (D) expressed by the above formula 3 by photoelectrically converting the light resulting from the interference between the reflected light Lr and the reference light Ld.

The phase of the reflected light Lr and the phase of the reference light Ld are aligned when the distance from the waveguide 161 to the surface of the object 30 is an integer multiple of the wavelength of the emitted light Lx (i.e., the laser light Lb). Therefore, the measuring device 10C can obtain imaging results of the surface distribution of the object 30 in the same way as the measuring device 10 shown in FIG. 1 by appropriately controlling the distance to the object 30.

Although the preferred embodiment of the present disclosure has been described in detail above with reference to the attached drawings, the technical scope of the present disclosure is not limited to such examples. It is clear that a person with ordinary knowledge in the technical field of the present disclosure can conceive of various modified or revised examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

Furthermore, the effects described in this specification are merely descriptive or exemplary and are not limiting. In other words, the technology disclosed herein may achieve other effects that are apparent to a person skilled in the art from the description in this specification, in addition to or in place of the above effects.

Note that the following configurations also fall within the technical scope of the present disclosure.
(1)
At least two or more laser modules each having a light projecting element that projects a phase-modulated laser beam onto an object and a light receiving element that receives the laser beam reflected by the object, the at least two laser modules being provided at positions spaced apart from each other;
a calculation unit that derives an imaging result of the surface of the object by correcting a phase difference and combining the light receiving signals of the laser light received by the light receiving elements of each of the laser modules;
A measuring device comprising:
(2)
The measuring device according to (1), wherein each of the laser modules is provided so that the distance between the laser modules can be changed.
(3)
A distance measuring sensor is further provided to measure a distance to the object.
The measuring device described in (1) or (2), wherein the emission angle of the laser light emitted from each of the laser modules from the normal direction of the emission surface is controlled based on the distance to the target object measured by the distance measuring sensor.
(4)
The measuring device according to (3), wherein the distance measuring sensor is a ToF sensor that uses a vertical cavity surface emitting laser as a light source.
(5)
The measurement apparatus according to (3) or (4), wherein the emission angle of the laser light is smaller than 1 degree.
(6)
The measurement device described in any one of (3) to (5), wherein each of the laser modules and the distance measurement sensor are provided on the same surface.
(7)
The measurement device described in any one of (1) to (6), wherein the calculation unit derives the imaging result by combining the received light signals for each pair of any two of the laser modules.
(8)
The measurement apparatus according to (7), wherein the calculation unit performs an inverse Fourier transform on the combined received light signal to derive a function indicating a surface distribution of the object as the imaging result.
(9)
each of the laser modules scans an area of the surface of the object by changing an emission angle of the laser light;
The measurement device according to any one of (1) to (8), wherein the calculation unit derives the imaging result of the region of the object.
(10)
The measurement device according to any one of (1) to (9), further comprising a bandpass filter on a light receiving surface of the light receiving element, the bandpass filter selectively transmitting a wavelength band including an oscillation wavelength of the laser light.
(11)
The measuring device according to any one of (1) to (10), wherein the light-projecting element is a semiconductor laser.
(12)
The measuring device according to any one of (1) to (11), wherein the light receiving element is a photodiode.
(13)
the light projecting element includes a waveguide provided on a light receiving surface of the light receiving element, and a diffraction grating that outputs a part of the laser light propagating through the waveguide to an opposite side to the light receiving element,
The measuring device according to any one of (1) to (12), wherein the light receiving element receives interference light between a portion of the laser light reflected by the object and a portion of the laser light emitted toward the light receiving element by the diffraction grating.
(14)
The measuring device according to (13), wherein the distance between the object and the light-projecting element is controlled to be an integer multiple of an oscillation wavelength of the laser light.
(15)
The measuring device according to any one of (1) to (14) above, which is mounted on a mobile terminal, a moving body, or a robot device.
(16)
At least two laser modules each having a light projecting element that projects a phase-modulated laser beam onto an object and a light receiving element that receives the laser beam reflected by the object, the at least two laser modules being provided at positions spaced apart from each other;
a calculation unit that derives an imaging result of the surface of the object by correcting a phase difference and combining the light receiving signals of the laser light received by the light receiving elements of each of the laser modules;
A measurement system comprising:

REFERENCE SIGNS LIST 10 Measuring device 20 Measurement point 30 Target object 50 Network 70 Cloud 100 Main body 110, 110A, 110B, 110C, 110D Laser module 111 Light-emitting element 112 Light-receiving element 120 Distance measurement sensor 131 Control unit 132 Calculation unit 133 Communication unit 140A, 140B, 140C, 140D Leg 150 Installation unit 161 Waveguide 162 Diffraction grating 163 Microlens 170 Semiconductor substrate 171 Photoelectric conversion unit 173 Pixel separation unit 174 Insulation layer

Claims (16)

At least two or more laser modules each having a light projecting element that projects a phase-modulated laser beam onto an object and a light receiving element that receives the laser beam reflected by the object, the at least two laser modules being provided at positions spaced apart from each other;
a calculation unit that derives an imaging result of the surface of the object by correcting a phase difference and combining the light receiving signals of the laser light received by the light receiving elements of each of the laser modules;
A measuring device comprising: The measurement device according to claim 1, wherein each of the laser modules is provided so that the distance between them can be changed. A distance measuring sensor is further provided to measure a distance to the object.
The measuring device according to claim 1 , wherein an emission angle of the laser light emitted from each of the laser modules from a normal direction of an emission surface is controlled based on the distance to the object measured by the distance measuring sensor. The measurement device according to claim 3, wherein the distance sensor is a ToF sensor that uses a vertical cavity surface emitting laser as a light source. The measurement device of claim 3, wherein the emission angle of the laser light is less than 1 degree. The measurement device according to claim 3, wherein each of the laser modules and the distance measuring sensor are provided on the same surface. The measurement device according to claim 1, wherein the calculation unit derives the imaging result by combining the received light signals for each pair of any two of the laser modules. The measurement device according to claim 7, wherein the calculation unit performs an inverse Fourier transform on the combined received light signal to derive a function indicating the surface distribution of the object as the imaging result. each of the laser modules scans an area of the surface of the object by changing an emission angle of the laser light;
The measurement device of claim 1 , wherein the computing unit derives the imaging result of the region of the object. The measurement device according to claim 1, further comprising a bandpass filter on the light receiving surface of the light receiving element that selectively transmits a wavelength band including the oscillation wavelength of the laser light. The measuring device according to claim 1, wherein the light-emitting element is a semiconductor laser. The measuring device according to claim 1, wherein the light receiving element is a photodiode. the light projecting element includes a waveguide provided on a light receiving surface of the light receiving element, and a diffraction grating that outputs a part of the laser light propagating through the waveguide to an opposite side to the light receiving element,
2. The measurement device according to claim 1, wherein the light receiving element receives interference light between a portion of the laser light reflected by the object and a portion of the laser light emitted toward the light receiving element by the diffraction grating. The measuring device according to claim 13, wherein the distance between the object and the light-projecting element is controlled to an integer multiple of the oscillation wavelength of the laser light. The measuring device according to claim 1, which is mounted on a mobile terminal, a mobile body, or a robotic device. At least two laser modules each having a light projecting element that projects a phase-modulated laser beam onto an object and a light receiving element that receives the laser beam reflected by the object, the at least two laser modules being provided at positions spaced apart from each other;
a calculation unit that derives an imaging result of the surface of the object by correcting a phase difference and combining the light receiving signals of the laser light received by the light receiving elements of each of the laser modules;
A measurement system comprising:

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