JP2017106754A - Measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measurement device capable of reducing the chances of allowing a high-power laser light to exit in a certain direction even if a maximum swing angle of a swinging mirror is varied.SOLUTION: A measurement device 100 is configured to scan light emitted by a light transmitter 20 and reflected by a swinging mirror 30 in a fixed space and to receive at a light receiver 21 the light reflected from an object 80 located within the space, and includes a mirror controller 2 configured to make the swinging mirror 30 swing in such a way that a swing angle of the swinging mirror 30 periodically varies, and a light controller 3 configured to vary flux of the light emitted by the light transmitter 20 in conjunction with the swinging motion of the swinging mirror 30.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a measurement apparatus that scans a space in a certain range with a laser beam and measures a distance to an object in the space.

  Conventionally, in a measuring device that reflects a laser beam by a oscillating mirror and scans the space, the reflected light of the laser beam is used to maintain the detection accuracy of the maximum oscillating angle while changing the maximum oscillating angle of the oscillating mirror. A technique for changing the position of a light receiving unit that receives light is known (see Patent Document 1). In the case of scanning using a resonance type oscillating mirror, the resonance frequency does not change and the time resolution is constant even if the maximum oscillation angle of the oscillating mirror is different. For this reason, by making the maximum swing angle of the oscillating mirror variable, for example, the maximum swing angle is first increased to measure a wide range roughly, and then the maximum swing angle is decreased to increase the spatial resolution. Application such as intensive measurement of a partial range becomes possible. In the case of scanning using a resonant oscillating mirror, the position of the laser beam (laser spot) is represented by a sine function (sine wave) with time as a variable. That is, when the laser beam comes near the end of the scanning range (maximum deflection angle), the moving speed of the laser beam becomes slow, and the laser power irradiated to the unit length per unit time increases. For this reason, high-power laser light can be emitted in a certain direction. As a technique to reduce the danger of high-power laser light to humans, in a scanner that scans with a light beam such as laser light, a light blocking plate that limits the maximum scanning angle of the outgoing light beam is fixed. The technique to provide is known (refer patent document 2).

JP 2012-22095 A Japanese Patent Laid-Open No. 06-236450

  However, in the technique of Patent Document 2, since the position of the light blocking plate is fixed, when the maximum deflection angle of the oscillating mirror is made variable, the vicinity of the maximum deflection angle depends on the maximum deflection angle of the oscillating mirror. Therefore, it is impossible to prevent high-power laser light from being emitted from the measuring device.

  Therefore, an object of the present invention is to provide a measuring apparatus that can reduce the emission of high-power laser light in a certain direction even if the maximum deflection angle of the oscillating mirror is varied.

  In order to achieve the above object, a measuring apparatus according to one embodiment of the present invention scans a certain space with light emitted from a light transmitting unit and reflected by a oscillating mirror, and reflects light reflected from an object in the space. A measurement device that receives light at a light receiving unit, based on a mirror control unit that oscillates the oscillating mirror so that the oscillation angle of the oscillating mirror periodically changes, and a change in the oscillation angle of the oscillating mirror The light control for controlling the light beam emitted from the light transmitting unit to a value exceeding a certain reference value during a part of the predetermined period and to a light beam value equal to or less than the certain reference value in the other part of the predetermined period A part.

  As a result, there is a possibility that the average light intensity can be lowered below the certain reference value due to the influence of the period during which the luminous flux in the predetermined period is less than the certain reference value. There is an effect that it is possible to measure a distant distance that cannot be measured. As an example, the predetermined period, the predetermined reference value, and the period during which the luminous flux is equal to or lower than the predetermined reference value are determined if there is a predetermined reference determined by laws and regulations in consideration of the influence of the laser beam on the human body. It can be determined to meet the criteria. In other words, the predetermined period, the constant reference value, and the period in which the luminous flux is equal to or less than the certain reference value are such that the integrated amount (light quantity) of the laser beam in the predetermined period (for example, 100 seconds) is equal to or smaller than a certain threshold ( (Predetermined criteria) may be established. In this case, the amount of light over a certain period of the light beam (laser light or the like) emitted from the light transmitting unit in the low angular velocity period in which the angular velocity of the swing angle of the oscillating mirror is equal to or less than the predetermined velocity is within a range according to a predetermined standard. Since the light flux is controlled so as to be within the range, the emission of high-power (high light amount) laser light in a certain direction (scanning direction during the low angular velocity period) is reduced. Here, the high power is, for example, power exceeding a range in accordance with a predetermined standard.

  For example, the measurement apparatus further includes a measurement mechanism for measuring a swing angle of the oscillating mirror, and the light control unit performs the control based on a measurement result of the swing angle of the oscillating mirror by the measurement mechanism. It may be done. This measuring apparatus can measure the swing angle of the swing mirror even when the maximum swing angle of the swing mirror is changed. In contrast to the conventional technology in which a high power laser beam is emitted in a scanning range where the temporal change (angular velocity) of the swing angle of the oscillating mirror is low with the luminous flux kept constant, this measurement device uses the oscillation angle of the oscillating mirror. Accordingly, since the light flux such as laser light emitted from the light transmitting unit is controlled to change, it is possible to reduce the emission of high-power laser light in a certain direction.

  For example, the mirror control unit oscillates the oscillating mirror so that the deflection angle of the oscillating mirror changes at a constant period, and the light control unit transmits the oscillating mirror measured by the measurement mechanism. In a first period having a length corresponding to one cycle of a change in deflection angle, a light flux emitted from the light transmission unit has a first value, and in the second period having a predetermined time length including the first period, the light transmission The control may be performed so that the average value of the luminous flux emitted from the unit becomes a second value smaller than the first value.

  Accordingly, a distance range that satisfies a predetermined standard of suppressing the influence on the human body by suppressing the power corresponding to the light flux of the second value on average over a period longer than the second period and that is relatively measurable. Can be expanded.

  For example, the light control unit may perform the control by periodically changing the light beam according to the magnitude of the angular velocity of the swing angle of the oscillating mirror measured by the measurement mechanism.

  As a result, the light flux such as laser light emitted from the light transmitting unit is controlled to change according to the absolute value of the angular velocity (amount of change per unit time) of the swing angle of the oscillating mirror that periodically changes. It is possible to reduce the emission of high-power laser light in a certain direction.

  For example, when the magnitude of the angular velocity of the swing angle of the oscillating mirror measured by the measurement mechanism is less than or equal to a predetermined threshold, the light control unit causes the light transmission unit to emit a light beam having a predetermined value or less. It is good also as performing control.

  As a result, the amount of laser light or the like integrated in the angular range (scanning range) of the oscillating mirror where the absolute value of the angular velocity of the oscillating mirror that changes periodically can be relatively small can be reduced. .

  For example, the light control unit may perform the control so that the light transmitting unit emits a light beam proportional to the magnitude of the angular velocity of the swing angle of the oscillating mirror measured by the measurement mechanism.

  As a result, the integrated amount of power such as laser light per unit angle in the entire oscillation period of the oscillation mirror can be suppressed to a constant amount that does not greatly affect the human body. Further, the measurable distance range near the center of the scanning range by laser light or the like can be expanded.

  For example, the light-receiving unit reflects light reflected from the object by the mirror surface of the oscillating mirror and another oscillating mirror having the same oscillating axis and oscillating angle as the oscillating mirror. The light control unit receives light, and the light control unit determines a light beam that is inversely proportional to an apparent area of the mirror surface as viewed from the light receiving unit, which is determined based on a swing angle of the oscillating mirror measured by the measurement mechanism. It is good also as performing the said control so that a light transmission part may emit.

  Thereby, it is possible to reduce the emission of high-power laser light in a certain direction, and to keep a measurable distance range constant regardless of the swing angle of the oscillating mirror.

  For example, the measuring mechanism is opposed to the light source with the light source and the mirror surface of the oscillating mirror sandwiched, and the degree of the mirror surface blocking the light from the light source changes according to the deflection angle of the oscillating mirror. A light receiving element arranged at a position to detect the swing angle of the oscillating mirror by detecting the amount of light received by the light receiving element.

  Thereby, the deflection angle of the oscillating mirror can be measured appropriately.

  For example, the light source and the light receiving element in the measurement mechanism may be arranged at positions deviating from a path through which light emitted from the light transmitting unit and reflected by a swinging mirror passes.

  Thereby, it is suppressed that the scanning range is narrowed by the light source and the light receiving element of the measurement mechanism.

  For example, the light source and the light receiving element in the measurement mechanism may be configured such that the mirror surface completely transmits light directed from the light source to the light receiving element in one of the cases where the swing angle of the oscillating mirror is maximum and minimum. On the other hand, the mirror surface does not shield light from the light source toward the light receiving element, and the mirror surface transmits light from the light source to the light receiving element between the maximum and minimum deflection angles. It is good also as arrange | positioning in the position which light-shields partially.

  Accordingly, the dynamic range related to the amount of received light can be increased by the light receiving element in the measurement mechanism, and the measurement accuracy of the swing angle of the oscillating mirror can be improved.

  Note that the present invention can be realized not only as a measurement apparatus including such a characteristic processing unit, but also as a measurement method including steps executed by the characteristic processing unit included in the measurement apparatus. be able to.

  Further, the present invention can be realized as a program for causing a computer to function as a characteristic processing unit included in the measurement apparatus, or a program for causing a computer to execute characteristic steps in a measurement method performed by the measurement apparatus. Needless to say, such a program can be distributed via a computer-readable non-transitory recording medium such as a CD-ROM (Compact Disc-Read Only Memory) or a communication network such as the Internet.

  According to the measurement device of one embodiment of the present invention, even when the maximum deflection angle of the oscillating mirror is changed, the emission of high-power laser light in a certain direction can be reduced.

It is a schematic block diagram of the measuring apparatus which concerns on embodiment. It is a functional block diagram of a measuring device. It is a block diagram of a phase detector. It is a figure which shows the example of arrangement | positioning of the light source and light receiving element in the measurement mechanism which measures the deflection angle (oscillation angle) of an oscillation mirror. It is a figure which shows the measurement principle of the deflection angle of a rocking | fluctuation mirror. It is a figure which shows an example of a structure of the measurement mechanism which measures the deflection | deviation angle of a rocking | fluctuation mirror. It is a figure which shows the example of arrangement | positioning of the light source and light receiving element in the measurement mechanism which measures the deflection | deviation angle of a rocking | fluctuation mirror. It is a figure which shows the example of arrangement | positioning of the light source and light receiving element in the measurement mechanism which measures the deflection | deviation angle of a rocking | fluctuation mirror. It is a figure which shows the example of arrangement | positioning of the light source and light receiving element in the measurement mechanism which measures the deflection | deviation angle of a rocking | fluctuation mirror. It is a figure which shows the example of arrangement | positioning of the light source and light receiving element in the measurement mechanism which measures the deflection | deviation angle of a rocking | fluctuation mirror. It is a figure which shows the change of the degree by which the progress of the measurement light for shake angle measurement is interrupted | blocked according to the change of the shake angle of the rocking | fluctuating oscillating mirror. It is a figure which shows the relationship between a mirror rocking angle signal and a scanning period. It is a figure which shows the relationship between a mirror rocking | fluctuation angle differential signal and a scanning period. It is a figure which shows the relationship between a scanning period and a measurement unit period. It is a figure which shows the relationship between a measurement unit period and laser power. It is a figure which shows the relationship between a scanning period and a laser control signal. It is a figure which shows the change of the apparent area of the mirror surface of the oscillating mirror seen from the light-receiving part according to the deflection angle of the oscillating mirror. It is a figure which shows the time change of the light receivable amount of a light-receiving part. It is a figure which shows the time change of the power of a laser beam.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present invention. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. The invention is specified by the claims. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims are not necessarily required to achieve the object of the present invention, but are described as constituting more preferable embodiments. Is done.

(Embodiment 1)
Hereinafter, measuring apparatus 100 according to Embodiment 1 will be described with reference to FIGS.

[1. Overall configuration of measuring device]
First, the main configuration of the measuring apparatus 100 according to the first embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a measuring apparatus 100 according to the first embodiment. In FIG. 1, an arrow line represents a light path. In the figure, in addition to the measuring apparatus 100, an object 80 that is a target of distance measurement (ranging) is shown.

  As shown in FIG. 1, the measuring apparatus 100 according to the present embodiment includes a housing 101 having an opening to the right in FIG. The opening portion of the housing 101 may be provided with an optical plate or the like that shields light other than the lens or the light receiving purpose. Inside the housing 101, there are a light transmitting unit 20, a light receiving unit 21, a swinging mirror 30, and a swinging angle (swinging angle) of the swinging mirror 30 as components for ranging (for spatial scanning). A light receiving element 10 and a light source 11 are disposed as components of the measuring mechanism 5 (described later). The measuring apparatus 100 is, for example, a laser range finder, and reflects the laser light by the oscillating mirror 30 and scans the space where the object (measuring object) 80 is located. The distance from the measuring device 100 is measured.

  The light transmission unit 20 includes a light source such as a laser diode, for example, and laser light (ranging emission light) is directed toward the oscillating mirror 30 based on a laser control signal from a light control unit 3 (described later) that drives the light source. Also called).

  The oscillating mirror 30 is, for example, a MEMS (Micro Electro Mechanical System) mirror, has a mirror surface formed on a silicon substrate, and oscillates mainly at a specific resonance frequency about a predetermined oscillation axis C. The swing axis C extends in the Z-axis direction in FIG. The oscillating mirror 30 oscillates about the oscillating axis C and reflects the laser light from the light source of the light transmitting unit 20 toward the object 80, thereby reciprocating in one axis direction (for example, the Y axis direction). The space is scanned with laser light (ranging emission light). A part of the ranging outgoing light reflected by the object 80 existing in the space passes through the opening of the housing 101 and hits the swinging mirror 30 in the housing 101. The oscillating mirror 30 receives the distance measuring outgoing light reflected by the object 80 and reflects it toward the light receiving unit 21.

  The light receiving unit 21 is composed of, for example, an avalanche photodiode. The light receiving unit 21 receives a part of the laser light (ranging outgoing light) reflected by the object 80 via the oscillating mirror 30, and based on the received laser light, a light reception signal indicating the amount of received laser light. (Electrical signal) is generated. The measuring apparatus 100 has a hole through which the laser light emitted from the light transmitting unit 20 passes when it travels toward the oscillating mirror 30, and is reflected from the object 80 reflected by the oscillating mirror 30. You may provide a perforated mirror etc. which has a reflective surface which reflects light toward the light-receiving part 21.

  In the measurement mechanism 5 for the swing angle (oscillation angle) of the oscillating mirror 30, light (oscillation angle measurement light) that is emitted only from a DC component without modulation from the light source 11 is received by the light receiving element 10 and the light is received. The light source 11 and the light receiving element 10 are arranged at a position where the deflection angle can be measured based on the amount of light. With this arrangement, the degree to which the light receiving element 10 can receive light without being blocked by the mirror surface of the oscillating oscillating mirror 30 in the oscillating angle measuring light from the light source 11 changes according to the oscillating angle.

[2. Functional configuration of measuring device]
Next, the functional configuration of the measuring apparatus 100 will be described with reference to FIG. FIG. 2 is a functional block diagram of the measuring apparatus 100. In FIG. 2, a solid arrow represents an electric signal transmission path, and a broken arrow represents a light path.

  As shown in FIG. 2, the measurement apparatus 100 includes a control unit 1, a measurement mechanism 5, an amplifier 15, an amplifier 22, a bandpass filter (BPF: Band) in addition to the oscillating mirror 30, the light transmission unit 20, and the light reception unit 21. Pass Filter) 27 and a phase detector 28 are provided.

  The control unit 1 is, for example, a microcomputer (microcomputer), and includes an electronic circuit including a microprocessor, a memory, a clock generator, an input / output interface, and the like. Then, the control unit 1 executes a control program stored in the memory by a microprocessor, and a control signal for controlling each unit of the measurement apparatus 100 such as the light transmission unit 20, the oscillating mirror 30, the measurement mechanism 5, and the like. Has a function of outputting. The control unit 1 includes a mirror control unit 2 and a light control unit 3 as functional components.

  The mirror control unit 2 has a function of driving the oscillating mirror 30. The mirror control unit 2 generates a oscillating mirror control signal for driving the oscillating mirror 30 to oscillate the oscillating mirror 30 so that the oscillating angle of the oscillating mirror 30 changes at a constant period based on the clock signal, for example. And output to a swing mechanism (not shown) of the swing mirror 30. The oscillating mirror control signal is a signal that defines the drive frequency and the oscillating force, and is, for example, a sine wave signal having a constant period. Thereby, the oscillating mirror 30 is oscillated around the oscillating axis C by the oscillating mechanism. The mirror control unit 2 adjusts the generated swing mirror control signal so that the target swing angle is obtained. Since the oscillation of the oscillating mirror 30 by the oscillating mechanism is affected by the environmental temperature or the like, the deflection angle of the oscillating mirror 30 cannot be specified by calculation using the oscillating mirror control signal, but is measured by the measurement mechanism 5. it can. The mirror controller 2 can set and change the target deflection angle at any time according to a user operation or a predetermined processing procedure. For example, to set the maximum deflection angle to a large value so that the measuring apparatus 100 can roughly measure a wide range, and then intensively measure only the range in which the user is interested or only the range in which some object is detected. For example, the maximum deflection angle can be set small. As long as the oscillating mirror 30 used for scanning the space with the laser beam in the measuring apparatus 100 oscillates at the resonance frequency, the time resolution is constant regardless of the maximum deflection angle, and scanning is performed as the maximum deflection angle is decreased. The spatial resolution with respect to the direction is increased.

  The light control unit 3 generates a laser control signal for causing the light source of the light transmission unit 20 to emit laser light and supplies the laser control signal to the light transmission unit 20. The laser control signal includes a sinusoidal amplitude modulation component having a constant frequency, such as 10 MHz, and the light transmission unit 20 emits modulated laser light (ranging emission light). The laser control signal is a signal further including information for controlling the output energy (power) of the laser. The output energy of the laser corresponds to the amount of light (luminous energy) proportional to the luminous flux of the laser beam. The unit of luminous flux is lumen (lm).

  The light reception signal generated by the light receiving unit 21 is amplified by the amplifier 22 and input to the BPF 27. The BPF 27 applies a filtering process to the amplified light reception signal to pass the frequency of the modulation component of the distance measurement outgoing light, and the light reception signal from which the component of the fluctuation angle measurement light is removed is sent to the phase detector 28. input.

  The phase detector 28 detects the phase difference between the distance measurement emitted light and the modulation component based on the distance measurement output light that appears in the light reception signal, and inputs the phase signal indicating the phase difference to the control unit 1. The control unit 1 (microcomputer) calculates the distance from the measuring apparatus 100 to the object (measurement object) 80 based on the phase signal. An example of the phase detector 28 is shown in FIG. The phase detector 28 illustrated in FIG. 3 is a quadrature detector, which multiplies the light reception signal input from the BPF 27 by a sine signal and a cosine signal by the mixers 40a and 40b, respectively, to generate an I signal and a Q signal. Get. Here, the sin signal is the same signal as the modulation component included in the laser control signal generated by the light control unit 3, and the cos signal is a signal obtained by shifting the 90 ° phase of the modulation component included in the laser control signal. is there. Using the frequency f of the modulation component and the time variable t, the phase is φ, the received light signal input from the BPF 27 is expressed as Asin (2πft + φ), the sin signal is expressed as Bsin (2πft), and the cos signal is expressed as Bcos (2πft). In other words, the I signal that is output from the mixer 40a is expressed by the following expression 1, and the Q signal that is output from the mixer 40b is expressed by the following expression 2.

I = Asin (2πft + φ) × Bsin (2πft)
= AB (cos (φ) −cos (2 × 2πft + φ)) / 2 (Formula 1)
Q = Asin (2πft + φ) × Bcos (2πft)
= AB (sin (φ) + sin (2 × 2πft + φ)) / 2 (Formula 2)

  The phase detector 28 passes the low-pass filters (LPFs) 41a and 41b for each of the I signal and the Q signal, so that the second term on the right side of Formula 1 and Formula 2 (frequency twice the modulation component). Component term) is attenuated to obtain I ′ signal and Q ′ signal and input to the control unit 1 as phase signals. The control unit 1 can obtain the phase φ from the angle of the vector sum of the orthogonal I ′ signal and Q ′ signal. The control unit 1 calculates a time difference from light emission to light reception based on the difference between the phase of the laser light emitted from the light transmitting unit 20 and the phase of the laser light received by the light receiving unit 21, and 1 / of the time difference is calculated. The distance from the measuring device 100 to the object 80 is calculated (measured) by multiplying 2 by the speed of light. Note that the control unit 1 can output the calculated distance.

  The measurement mechanism 5 has a function of measuring a swing angle (swing angle) of the swing mirror 30 and includes a light source 11 such as a light emitting diode and a light receiving element 10 such as a photodiode. The deflection angle as a measurement result by the measurement mechanism 5 is output as a swing angle measurement optical signal. That is, the light receiving element 10 of the measurement mechanism 5 outputs a swing angle measurement optical signal indicating the amount of received light, which is proportional to the swing angle of the swing mirror 30. This oscillation angle measurement optical signal is amplified by the amplifier 15 and input to the control unit 1. The swing angle of the swing mirror 30 and the swing cycle or swing frequency can be obtained from the swing angle measurement optical signal output from the measurement mechanism 5 and changing with time. Based on the deflection angle measured by the measuring mechanism 5, the mirror control unit 2 that drives the oscillating mirror 30 performs, for example, feedback control related to the oscillation of the oscillating mirror 30, and for example, the maximum oscillation angle (maximum oscillation angle). Control of fluctuations in the angle) is performed. Further, the light control unit 3 generates a laser control signal so as to change the luminous flux of the laser light emitted from the light transmission unit 20 based on the deflection angle measured by the measurement mechanism 5. The light control unit 3 generates a laser control signal adjusted so as to change the output energy of the laser in order to change the luminous flux of the laser light, and supplies the laser control signal to the light transmission unit 20.

[3. Arrangement of light source and light receiving element in measurement mechanism]
Hereinafter, the arrangement of the light source 11 and the light receiving element 10 in the measurement mechanism 5 described above will be described.

  FIG. 4 is a diagram illustrating an arrangement example of the light source 11 and the light receiving element 10 in the measurement mechanism 5 that measures the swing angle (swing angle) of the swing mirror 30. As shown in the figure, the light source 11 and the light receiving element 10 face each other across the end in the width direction of the mirror surface of the oscillating mirror 30, and the oscillation angle measuring light emitted from the light source 11 is transmitted by the light receiving element 10. It is arranged at a position where light can be received. The oscillating mirror 30 oscillates with the oscillating axis C passing through the center of the mirror surface width and extending in the mirror surface height direction as the center of oscillation. When the oscillating mirror 30 is oscillated, the amount by which the oscillating angle measurement light is blocked by the mirror surface of the oscillating mirror 30 fluctuates. The light intensity increases or decreases.

  FIG. 5 is a diagram illustrating the principle of measuring the deflection angle of the oscillating mirror 30. In the same figure, the arrangement | positioning seen from the direction along the rocking | fluctuation axis | shaft C of the rocking | fluctuation mirror 30 shown in FIG. 4 is represented. A broken line indicates the position of the mirror surface when the oscillating mirror 30 is swung to the maximum. The solid line shows the position of the mirror surface when the oscillating mirror 30 is not oscillating (the intermediate position between the two oscillating maximum positions). Here, at the position indicated by the solid line, it is assumed that the swing angle θ of the swing mirror 30 is 0 °, and the swing angle θ is represented by the normal line of the mirror surface of the swing mirror 30 passing through the swing axis C. At the position of the broken line, the deflection angle θ is the maximum value θmax or the minimum value θmin. The swing angle θ of the oscillating mirror surface is also an angle formed by the mirror surface and the mirror surface indicated by a solid line. FIG. 5 shows a state in which the mirror surface width of the oscillating mirror 30 is projected upward from the lower side of FIG. 5, and the length of the mirror surface projected when the deflection angle θ is 0 ° is used as a reference. The difference between the projected length of the mirror surface at a certain deflection angle θ and the reference length is represented by d. Since d is a function of the swing angle θ of the oscillating mirror 30, the swing angle θ can be obtained by measuring d. As shown in FIG. 6, the emitted light from the light source 11 is converted into parallel light by the lens 51 that is a collimator lens, and a mask 50 having a hole in the center is disposed in front of the lens 51, so that the deflection angle θ is zero. The amount of light received by the light receiving element 10 may be zero only when the angle is. As a result, an offset component is not included in the oscillation angle measurement optical signal output from the light receiving element 10, so that the dynamic range of the light receiving element 10 can be increased. When arranged as shown in FIG. 6, d can be expressed by the following Expression 3 using the deflection angle θ. r is half the width of the mirror surface of the oscillating mirror 30.

  d = r (1-cos θ) (Formula 3)

  The amount of oscillation angle measurement light received by the light receiving element 10 is also proportional to d. The proportionality constant is a constant determined by the sensitivity of the light receiving element 10, the amount of oscillation angle measurement light emitted from the light source 11, and the like. By measuring this proportionality constant in advance, the deflection angle θ of the oscillating mirror 30 can be derived from the oscillation angle measurement optical signal indicating the amount of light received by the light receiving element 10.

  The light source 11 and the light receiving element 10 in the measurement mechanism 5 described above may be arranged as shown in FIG. FIG. 4 shows an example in which the optical axis of the oscillation angle measurement light directed from the light source 11 toward the light receiving element 10 is substantially perpendicular to the oscillation axis C of the oscillation mirror 30. In the arrangement shown in FIG. The optical axis is inclined so as to intersect with a plane perpendicular to the oscillation axis C at a relatively large angle (for example, 50 °). The height direction of the mirror surface of the oscillating mirror 30 is the direction of the oscillating axis C, and the light source 11 sandwiches one end of the mirror surface in the width direction of the mirror surface of the oscillating mirror 30 perpendicular to the oscillating axis C. 7 and the arrangement shown in FIG. 4 are the same as the arrangement shown in FIG. In the arrangement shown in FIG. 7, the plane (virtual plane) formed by the path 23 of the distance measurement emission light reflected by the oscillating oscillating mirror 30 and scanning the space is separated from the light source 11 and the light receiving element 10. doing. For this reason, in the arrangement shown in FIG. 7, the light source 11 or the light receiving element 10 does not block the distance measuring outgoing light. In the example of FIG. 7, the light source 11 is disposed at a position that does not overlap with the plane formed by the path 23 of the distance measurement outgoing light, faces the light source 11, and receives light at a position opposite to the light source 11 with respect to the plane. Element 10 is arranged. In other words, the light source 11 and the light receiving element 10 are arranged at positions deviating from the path through which the light emitted from the light transmitting unit 20 and reflected by the oscillating mirror 30 passes.

  Another arrangement example of the light source 11 and the light receiving element 10 is shown in FIG. The light source 11 and the light receiving element 10 face each other across the end in the width direction (direction perpendicular to the swing axis C) of the mirror surface of the swing mirror 30 in the example of FIG. However, it differs in that it is opposed across one end of the mirror mirror 30 in the height direction (the direction of the swing axis C). Even in the arrangement of FIG. 8, for example, if the direction vector from the light source 11 to the light receiving element 10 has a component in the width direction of the oscillating mirror 30 (the component is other than zero), the oscillating mirror is used. The light amount of the swing angle measurement light received by the light receiving element 10 changes according to the 30 swing angle. For this reason, the swing angle of the swing mirror 30 can be derived from the swing angle measurement optical signal output from the light receiving element 10.

  Further, another arrangement example of the light source 11 and the light receiving element 10 is shown in FIG. The example of FIG. 9 is also an example of an arrangement that prevents the distance measurement light from entering the light source 11 or the light receiving element 10 on the path through which the distance measurement light passes, and is an oscillation that reflects the distance measurement light. This is an example when the mirror surface of the mirror is large. In the example of FIG. 9, the light source 11 and the light receiving element 10 are arranged above the plane formed by the path 23 of the distance measurement outgoing light.

  Further, another arrangement example of the light source 11 and the light receiving element 10 is shown in FIG. In the figure, a lens (collimator lens) 11 a that collimates light from the light source 11 and a lens (condenser lens) 10 a that collects light on the light receiving element 10 are additionally shown. Further, in the drawing, the arrangement of the oscillating mirror 30 viewed from the direction along the oscillating axis C is shown. In the example of FIG. 10, as compared with the examples of FIGS. 4 and 5, the light source 11 is disposed at a position close to the swing axis C of the swing mirror 30, and the light receiving element 10 is disposed at a position away from the swing axis C. Has been. With such an arrangement, it is possible to increase the change in the amount of received oscillation angle measurement light that can be received by the light receiving element 10 by the oscillation of the oscillation mirror 30, and to measure the oscillation angle of the oscillation mirror 30. Accuracy can be increased. FIG. 11 shows how the degree of blocking of the swing angle measurement light directed toward the light receiving element 10 by the swing mirror 30 changes according to the swing angle of the swing swing mirror 30. Each of (a) to (c) in FIG. 11 shows a state in which the swing angle of the swing mirror 30 that swings between the maximum swing angle θmax and the minimum swing angle θmin is different. In each of () to (c), a filled pattern (pattern) is added to a portion where the oscillation angle measurement light 33 which is parallel light reaches. A filled pattern (pattern) is not added to the portion where the swing angle measurement light 33 is blocked by the swing mirror 30 and does not reach (that is, a solid white color). In FIG. 11, the state (a) shows a state in which the swing angle measuring light 33 is completely shielded by the mirror surface A of the swing mirror 30 having the maximum swing angle θmax, and the state (b) shows the maximum swing angle θmax. The state in which the swing angle measuring light 33 is partially shielded by the mirror surface of the swing mirror 30 which is smaller and larger than the minimum swing angle θmin is shown, and the state (c) is the minimum swing angle θmin. Depending on the mirror surface B of the oscillating mirror 30, the oscillating angle measuring light 33 is not shielded. That is, in the light source 11 and the light receiving element 10, the mirror surface of the oscillating mirror 30 completely transmits the light traveling from the light source 11 to the light receiving element 10 in one of the cases where the swing angle of the oscillating mirror 30 is maximum and minimum. The mirror surface shields light from the light source 11 to the light receiving element 10 on the other side, and the mirror surface transmits light from the light source 11 to the light receiving element 10 between the maximum and minimum deflection angles. It is arranged at a position where it is partially shielded. In this way, by arranging the light source 11 and the light receiving element 10 at a position that changes to any one of the states (a) to (c) due to the swing of the swing mirror 30, the amount of light received by the light receiving element 10 can be increased. The dynamic range is increased, and the measurement accuracy of the swing angle of the swing mirror 30 is sufficiently increased.

  Note that the positional relationship between the light source 11 and the light receiving element 10 in the measurement mechanism 5 described above may be reversed, and the reversal does not affect the function of measuring the deflection angle of the oscillating mirror 30. Further, the swing angle measurement light is reflected by the inside of the housing 101 of the measurement apparatus 100 and is removed by the BPF 27 even if it is received by the light receiving unit 21 for receiving the distance measurement outgoing light. That is, the BPF 27 suppresses the influence of the swing angle measurement light on the distance measurement.

[4. Control action of laser light emitted from the light transmission unit]
The light control unit 3 shown in FIG. 2 changes the luminous flux of the laser light emitted from the light transmission unit 20 in association with the swing of the swing mirror 30. Hereinafter, the control operation related to the output of the laser light (ranging emission light) emitted by the light transmission unit 20 by the light control unit 3 will be described with reference to FIGS. First, the conditions when the light control unit 3 controls the power of the laser light will be described, and then specific control contents will be described with reference to FIGS.

  An object 80 that is a measurement target of the measurement apparatus 100 reflects the distance measurement emitted light emitted from the light transmission unit 20 of the measurement apparatus 100 and reflected by the oscillating mirror 30 and exiting the housing 101.

  The measuring apparatus 100 measures the distance using the reflected light from the object 80 (referred to as distance measurement reflected light). When the light amount of the distance measurement reflected light is small, the S / N of the light reception signal output from the light receiving unit 21 is measured. Since the signal-to-noise ratio is lowered, the measurement accuracy is lowered.

  The amount of light received by the light receiving unit 21 for the distance measurement reflected light is proportional to the light amount of the distance measurement output light (laser light emitted from the light transmission unit 20), and is the square of the distance from the measuring apparatus 100 to the object 80 to be measured. Inversely proportional. Therefore, if the luminous flux of the distance measuring emitted light is increased by increasing the power of the distance measuring emitted light, the light amount of the distance measuring emitted light increases, so that the level of the light receiving signal output from the light receiving unit 21 is also increased. Increases accuracy. Here, the light flux is a radiant flux emitted in a certain direction per unit time, and the light quantity is the total amount of the light flux that passes through a certain surface within a certain time.

  On the other hand, as the distance increases, the level of the received light signal decreases and the measurement accuracy decreases. Therefore, the distance that can ensure the measurement accuracy required for the measurement apparatus 100 depends on the power of the distance measurement outgoing light. That is, the measuring apparatus 100 can secure the required accuracy and make the range of measurement variable by controlling the power of the ranging output light.

  For example, in a typical case where the measuring apparatus 100 is used indoors, a stationary wall or the like is located at a relatively far position from the measuring apparatus 100, and a person or an object placed in the room moves and is relatively Tend to be close to each other. In this typical example, it is necessary to measure the wall or the like by increasing the power of the laser beam (ranging emission light), but the measurement frequency may not be high, and an object placed in a person or a room is the power of the laser beam. It is possible to measure with lowering, but the measurement frequency needs to be high. Further, since the laser has a high power density and has a large influence on the human body, the laser must be used so that the power is in a range in accordance with a predetermined standard such as a legal regulation. Here, as a condition relating to the predetermined reference, using as an example a predetermined condition that the average power in a predetermined period (for example, 100 seconds) is equal to or less than a certain threshold (that is, limiting the integrated amount of laser light power in the predetermined period), Control of laser light will be described.

  In the measuring apparatus 100, the output of the laser beam emitted from the light transmitting unit 20 is controlled in synchronization with the oscillation cycle of the oscillation mirror. The control unit 1 derives a mirror swing angle signal indicating the swing angle of the swing mirror 30 from the swing angle measurement light signal, and the light control unit 3 generates a laser control signal based on the mirror swing angle signal. To do.

  That is, the light control unit 3 generates a laser control signal for controlling the power of the laser light based on the mirror swing angle signal indicating the swing angle of the swing mirror 30. By changing the power of the laser light, the luminous flux of the laser light emitted from the light transmitting unit 20 changes.

  FIG. 12 is a diagram showing the relationship between the mirror swing angle signal and the scanning period. A unit period required for the oscillating mirror 30 to swing from the maximum swing angle θmax to the minimum swing angle θmin is a scanning period T1, and the measuring apparatus 100 performs one-time measurement on the space in the scanning period T1. As shown in FIG. 13, the timing for dividing each scanning period T1 is a mirror oscillation angle differential signal (indicated by a solid line in the figure) obtained by differentiating a mirror oscillation angle signal (indicated by a broken line in the figure). It is obtained by detecting the timing when the value of.) Becomes zero. In the measuring apparatus 100, the laser beam is reflected by the oscillating mirror 30 that oscillates in one measurement in the scanning period T1, and the object to be measured (such as the object 80) is scanned for each angle in the range of scanning the space. The distance is measured. A period in which the scanning period T1 is combined a plurality of times is defined as a measurement unit period T2 that is a laser power control period. For example, the measurement unit period T2 when the scanning period T1 is combined five times is as shown in FIG.

  As shown in FIG. 15, the light control unit 3 controls to output laser light (ranging emission light) with high power only in one scanning period T1 among the scanning periods T1 constituting the measurement unit period T2. The laser control signal to be generated is generated and sent to the light transmitting unit 20. Then, the light control unit 3 generates a laser control signal that is controlled so as to be output at low power in each of the other scanning periods T1 and sends the laser control signal to the light transmission unit 20. The high power and the low power are determined so as to be equal to or less than a certain threshold value in the above-described predetermined condition when taking a temporal average in the measurement unit period T2. The scanning period T1 and the measurement unit period T2 are sufficiently shorter than a predetermined period (for example, 100 seconds) under the predetermined condition. Therefore, even if measurement is continuously performed by the measuring apparatus 100 over the predetermined period, the predetermined condition is satisfied. In other words, the light control unit 3 detects the light beam emitted by the light transmission unit 20 in the first period (scanning period T1) having a length corresponding to one cycle of the change in the swing angle of the swing mirror 30 measured by the measurement mechanism 5. In the second period (measurement unit period T2) having a predetermined time length including the first period, the average value of the luminous flux emitted by the light transmitting unit 20 is the first value (value of the luminous flux corresponding to high power). The light transmission unit 20 is controlled to change the light beam emitted by the light transmission unit 20 so that the second value (the value of the light beam corresponding to the power equal to or less than a certain threshold value) is smaller than one value.

[5. effect]
In this measuring apparatus 100, the swing angle of the swing mirror 30 can be appropriately measured by the swing angle measurement optical signal output from the measurement mechanism 5, and thus the swing mirror 30 swings so as to have an arbitrary maximum swing angle. Can be controlled. Further, the light control unit 3 uses the mirror swing angle signal indicating the swing angle of the swing mirror 30 based on the swing angle measurement light signal so that the light control unit 3 periodically changes the power of the laser beam. By controlling the above, it is possible to increase the power of the laser light in a short period of time and to measure the distance of a distant object to be measured, and to measure the distance of a nearby object to be measured with high frequency. And the average power of the laser beam output within the measurement unit period T2 can be kept low so as to satisfy a predetermined condition related to a predetermined standard such as a legal regulation. In this way, the laser beam power is increased in the short term, but in the long term, the average power of the laser beam is suppressed. The amount of light obtained by integrating the laser beam in the long term is within the range according to a predetermined standard. Thereby, it is possible to suppress the emission of high-power (high light amount) laser light in a certain direction (scanning direction in the low angular velocity period).

(Embodiment 2)
Hereinafter, an embodiment in which the measuring apparatus 100 according to Embodiment 1 is partially modified will be described. Since the measuring apparatus according to the present embodiment has the same configuration as the measuring apparatus 100 shown in the first embodiment (see FIGS. 1 and 2), description will be made using the same reference numerals for the constituent elements here. In the present embodiment, the control operation of the light control unit 3 is different from that of the first embodiment. Note that the points not described here are the same as those in the first embodiment.

  The light control unit 3 of the measurement apparatus 100 according to the present embodiment generates a laser control signal for controlling the power of the laser light (ranging emission light) emitted from the light transmission unit 20 to change with time. The light is sent to the light transmitter 20. The laser control signal generated by the light control unit 3 indicates the power of the laser beam by, for example, amplitude, and periodically changes every scanning period T1 (see FIG. 13) described above.

  FIG. 16 shows a temporal change in the laser control signal generated by the light control unit 3. As shown in the figure, the light control unit 3 shows the power of the laser beam (indicated by a solid line in the figure) as a oscillating mirror indicated by a mirror oscillation angle differential signal (indicated by a broken line in the figure). It is determined so as to be proportional to the absolute value of the change amount per unit time of 30 deflection angles, that is, the angular velocity (scanning velocity). This is due to the following reason.

  That is, as shown in FIG. 13 (solid-line mirror swing angle differential signal) and FIG. 16 (broken-line mirror swing angle differential signal), the swing mirror 30 has the angular velocity of the most swing angle at the intermediate timing of the scanning period T1. (Scanning speed) becomes faster. If the laser light power during the scanning period T1 is constant, the amount of integrated laser light power per unit angle in the scanning period T1 decreases as the scanning speed increases. It becomes the minimum at the intermediate timing of the period T1. When the measuring apparatus 100 measures the distance to the measurement object for each unit angle (for example, 1 °), the received light signal output from the light receiving unit 21 is the same S / W at any angle as long as the power of the laser beam is constant. N ratio. Accordingly, a period (a maximum swing angle θmax or the minimum shake angle θmin that is the end of the swing range of the swing mirror 30 or an angle near the angle) in which the scan speed is slow, that is, the time change of the swing angle is small. It is necessary to control the laser beam power so that the integrated amount of the laser beam power does not significantly affect the human body during the low angular velocity period. When the power of the laser beam during the scanning period T1 is made constant and this need is met, the power per unit angle near the center of the scanning range is determined by the power limited at the end of the oscillation range (end of the scanning range). The power of the laser beam becomes relatively small. In the measuring apparatus 100, since it is desirable that the measurable distance near the center of the scanning range is long, the method of making the power of the laser light constant in this way is not very useful. Therefore, the light control unit 3 makes the power of the laser light proportional to the absolute value of the scanning speed, as shown in FIG.

  In this way, the light control unit 3 is proportional to the magnitude of the angular velocity according to the magnitude of the angular velocity of the oscillating mirror 30 measured by the measurement mechanism 5 (absolute value of the scanning speed). As described above, the luminous flux emitted from the light transmitting unit 20 is changed. As a result, the integrated amount of power per unit angle over the entire scanning period T1 can be suppressed to a constant amount that does not significantly affect the human body, and the measurable distance range near the center of the scanning range can be expanded. . Note that the measuring apparatus 100 does not measure the distance to the measurement object for each unit angle (for example, 1 °) (that is, calculate the distance by acquiring a signal from the phase detector 28 in the control unit 1), The distance may be calculated at equal time intervals.

(Embodiment 3)
Hereinafter, another embodiment in which the measuring apparatus 100 according to Embodiment 1 is partially modified will be described. Since the measuring apparatus according to the present embodiment has the same configuration as the measuring apparatus 100 shown in the first embodiment (see FIGS. 1 and 2), description will be made using the same reference numerals for the constituent elements here. In the present embodiment, the control operation of the light control unit 3 is different from that of the first embodiment. Note that the points not described here are the same as those in the first embodiment.

  In the light control unit 3 of the measuring apparatus 100 in the present embodiment, the power of the laser light (ranging emission light) emitted by the light transmission unit 20 is inversely proportional to the amount of light that can be received by the light receiving unit 21. A laser control signal for control is generated and sent to the light transmitter 20. By changing the power of the laser light, the luminous flux of the laser light emitted from the light transmitting unit 20 changes.

  The amount of light that can be received by the light receiving unit 21 from the distance measuring light is proportional to the apparent area of the mirror surface of the oscillating mirror 30 viewed from the light receiving unit 21. That is, the light control unit 3 controls the light transmission unit 20 to emit a light beam that is inversely proportional to the apparent area of the mirror surface of the oscillating mirror 30 viewed from the light receiving unit 21. The apparent area of the mirror surface of the oscillating mirror 30 viewed from the light receiving unit 21 can be calculated based on the angular velocity of the oscillating mirror 30 (oscillating angle) measured by the measuring mechanism 5 or the deflection angle thereof. It is. FIG. 17 shows a change in the apparent area of the mirror surface of the oscillating mirror 30 as viewed from the light receiving unit 21 according to the deflection angle of the oscillating mirror 30. This figure is a view of the oscillating mirror 30 as viewed from the direction of the oscillating axis C. (A) and (b) of the figure show examples in which the swing angle of the swing mirror 30 differs due to swing. The distance measuring light is reflected by the mirror surface of the oscillating mirror 30 and received by the light receiving unit 21 through the lens 21a. If the angle between the direction from the swing axis C toward the light receiving unit 21 and the normal line of the mirror surface of the swing mirror 30 is θ, the apparent area of the mirror surface of the swing mirror 30 viewed from the light receiving unit 21 is Using the width Wm and the height H of the oscillating mirror 30, it is expressed as H · Wm cos θ. Since the swing angle (swing angle) of the oscillating mirror 30 differs between (a) and (b) in FIG. 17, the apparent width W (= Wm cos θ) of the mirror surface of the oscillating mirror 30 viewed from the light receiving unit 21. Is different. FIG. 18 shows the relationship between time (scanning period T <b> 1 in which the swing angle of the oscillating mirror changes) and the amount of light that can be received by the light receiving unit 21. The smaller the amount of light that can be received by the light receiving unit 21, the smaller the distance range that can be measured by the measuring apparatus 100. FIG. 19 shows a temporal change in the power of the laser light emitted from the light transmitting unit 20 under the control of the laser control signal by the light control unit 3. As shown in FIG. 19, the power of the laser light periodically changes every two scanning periods T1.

  In this way, by controlling the laser to emit light with a power inversely proportional to the apparent area of the mirror surface of the oscillating mirror 30 viewed from the light receiving unit 21, the temporal average power is lowered and the oscillating mirror 30 The measurable distance range can be kept constant regardless of the deflection angle. Note that by reducing the temporal average power of the laser light, it is possible to suppress the emission of the high-power laser light in a certain direction (scanning direction during a period in which the angular velocity of the oscillating mirror 30 is relatively low).

(Other embodiments, etc.)
As mentioned above, although the measuring apparatus was demonstrated using Embodiment 1-3, this invention is not limited to the said embodiment. That is, it goes without saying that the above-described embodiment is merely an example, and various modifications, additions, omissions, and the like can be made.

  In the said embodiment, the control part 1 (light control part 3) in the measuring apparatus 100 showed about the control of the power of the laser beam (ranging emission light) which the light transmission part 20 emits. In addition to this, even if an external device (external device) of the measuring apparatus 100 gives a power control signal to the measuring apparatus 100, the measuring apparatus 100 executes control of the power of the distance measuring outgoing light in accordance with this signal. Good. In that case, the external device receives the mirror swing angle signal from the measurement device 100, and in accordance with the mirror swing angle signal, the external device uses the power related to the distance measurement output light in the same manner as the light control unit 3. A control signal can be defined. In this case, the measuring apparatus 100 can vary the luminous flux of the distance measurement emitted light emitted from the light source of the light transmitting unit 20 in accordance with the power control signal.

  In the above embodiment, the laser control signal includes a sine wave amplitude modulation component having a constant frequency and further includes information for controlling the power of the laser beam. A signal including a sinusoidal amplitude modulation component having a constant frequency and a signal for controlling the power of the laser beam may be transmitted to the optical unit 20.

  In the above embodiment, the light receiving unit 21 receives the light reflected by the oscillating mirror 30 for a part of the distance measuring outgoing light reflected by the object 80. The light reflected from the mirror surface of the oscillating mirror 30, the oscillating axis C, and the other oscillating mirror having the same angular velocity of the oscillating angle may be received.

  In the second embodiment, the light control unit 3 changes the luminous flux emitted by the light transmission unit 20 so as to be proportional to the magnitude of the angular velocity of the swing angle of the swing mirror 30. In addition to this, when the magnitude of the angular velocity of the swing angle of the oscillating mirror 30 measured by the measuring mechanism 5 is equal to or less than a predetermined threshold, the light control unit 3 causes the light transmitting unit to emit a light beam having a predetermined value or less. It is good also as controlling.

  Moreover, the mirror control unit 2 and the light control unit 3 described above may be configured as separate microcomputers, or may be configured as electronic circuits that do not use a computer program.

  In addition, each device such as the measurement device and the external device specifically includes a microprocessor, a ROM (Read Only Memory), a RAM (Random Access Memory), a hard disk drive, a display unit, a keyboard, a mouse, and the like. A computer system may be included. A computer program is stored in the RAM or hard disk drive. Each device achieves its functions by the microprocessor operating according to the computer program. Here, the computer program is configured by combining a plurality of instruction codes indicating instructions for the computer in order to achieve a predetermined function.

  Furthermore, some or all of the constituent elements constituting each of the above-described devices may be configured by a single system LSI (Large Scale Integration). The system LSI is an ultra-multifunctional LSI manufactured by integrating a plurality of components on a single chip. Specifically, the system LSI is a computer system including a microprocessor, a ROM, a RAM, and the like. . A computer program is stored in the RAM. The system LSI achieves its functions by the microprocessor operating according to the computer program.

  Furthermore, some or all of the constituent elements constituting each of the above-described devices may be configured from an IC card that can be attached to and detached from each device or a single module. The IC card or module is a computer system that includes a microprocessor, ROM, RAM, and the like. The IC card or the module may include the super multifunctional LSI described above. The IC card or the module achieves its function by the microprocessor operating according to the computer program. This IC card or this module may have tamper resistance.

  Further, the present invention may be a method executed by each of the above devices. Further, the present invention may be a computer program that realizes these methods by a computer, or may be a digital signal composed of the computer program.

  Furthermore, the present invention relates to a non-transitory recording medium that can read the computer program or the digital signal by a computer, such as a flexible disk, a hard disk, a CD-ROM, an MO, a DVD, a DVD-ROM, a DVD-RAM, and a BD. (Blu-ray (registered trademark) Disc), recorded on a semiconductor memory, or the like. Further, the digital signal may be recorded on these non-temporary recording media.

  Further, the present invention may transmit the computer program or the digital signal via an electric communication line, a wireless or wired communication line, a network represented by the Internet, a data broadcast, or the like.

  The present invention may be a computer system including a microprocessor and a memory, wherein the memory stores the computer program, and the microprocessor operates according to the computer program.

  In addition, the program or the digital signal is recorded on the non-temporary recording medium and transferred, or the program or the digital signal is transferred via the network or the like. The computer system may be used.

  The measuring apparatus of the present invention can be used as, for example, a laser range finder for measuring a distance to an object.

DESCRIPTION OF SYMBOLS 1 Control part 2 Mirror control part 3 Light control part 5 Measurement mechanism 10 Light receiving element 10a, 11a, 21a, 51 Lens 11 Light source 15, 22 Amplifier 20 Light transmission part 21 Light receiving part 23 Path | route of ranging output light 27 Band pass filter ( BPF)
28 Phase detector 30 Oscillating mirror 33 Oscillating angle measuring light 40a, 40b Mixer 41a, 41b Low pass filter (LPF)
50 mask 80 object (measurement object)
100 Measuring device 101 Housing C Swing shaft

Claims (11)

A measuring device that scans a certain space with light emitted from a light transmitting unit and reflected by a oscillating mirror, and receives light reflected from an object in the space by a light receiving unit,
A mirror controller that swings the swing mirror so that the swing angle of the swing mirror periodically changes;
Based on the change in the swing angle of the oscillating mirror, the luminous flux of the light emitted from the light transmitting unit is set to a value that exceeds a certain reference value during a part of the predetermined period, and the constant reference value other than the part during the predetermined period. A measuring apparatus comprising: a light control unit that performs control to obtain the following luminous flux values. The measuring device further includes a measuring mechanism for measuring a swing angle of the oscillating mirror,
The measurement apparatus according to claim 1, wherein the light control unit performs the control based on a measurement result of a swing angle of the oscillating mirror by the measurement mechanism. The mirror control unit swings the swing mirror so that the swing angle of the swing mirror changes at a constant period,
In the first period of a length corresponding to one cycle of a change in the swing angle of the oscillating mirror measured by the measurement mechanism, the light control unit has a first value of a light beam emitted from the light transmission unit, The measuring apparatus according to claim 2, wherein the control is performed so that an average value of a light beam emitted from the light transmission unit becomes a second value smaller than the first value in a second period having a predetermined time length including one period. . The measurement apparatus according to claim 2, wherein the light control unit performs the control by periodically changing the light beam according to a magnitude of an angular velocity of a swing angle of the oscillating mirror measured by the measurement mechanism. . The light control unit performs the control so that the light transmission unit emits a light beam of a predetermined value or less when the angular velocity of the swing angle of the oscillating mirror measured by the measurement mechanism is a predetermined threshold value or less. 5. The measuring device according to claim 4. The measurement apparatus according to claim 4, wherein the light control unit performs the control such that the light transmission unit emits a light beam proportional to the angular velocity of the swing angle of the oscillating mirror measured by the measurement mechanism. The light receiving unit reflects reflected light reflected from the object by any mirror surface of the oscillating mirror and another oscillating mirror having the same oscillating axis and oscillating angle as the oscillating mirror. Receive light,
The light control unit emits a light beam that is inversely proportional to an apparent area of the mirror surface as viewed from the light receiving unit, which is determined based on a swing angle of the oscillating mirror measured by the measurement mechanism. The measurement apparatus according to claim 2, wherein the control is performed as follows. The measurement mechanism is a position where the light source and the mirror surface of the oscillating mirror are opposed to the light source, and the degree by which the mirror surface blocks the light from the light source according to the deflection angle of the oscillating mirror is changed. The measuring apparatus according to claim 2, further comprising: a light receiving element disposed at a position, wherein the swing angle of the oscillating mirror is measured by detecting the amount of light received by the light receiving element. The measurement apparatus according to claim 8, wherein the light source and the light receiving element in the measurement mechanism are arranged at positions deviating from a path through which light emitted from the light transmitting unit and reflected by a swing mirror passes. The light source and the light receiving element in the measurement mechanism are configured such that the mirror surface completely shields light directed from the light source toward the light receiving element in one of the cases where the swing angle of the oscillating mirror is maximum and minimum. On the other hand, the mirror surface does not block light traveling from the light source to the light receiving element, and the mirror surface partially transmits light traveling from the light source to the light receiving element between when the deflection angle is maximum and minimum. The measuring apparatus according to claim 8, wherein the measuring apparatus is disposed at a position where the light is shielded from light. The measuring apparatus according to claim 1, wherein the light control unit performs the control by periodically changing the light flux according to the magnitude of the angular velocity of the swing angle of the oscillating mirror.

Images