JP2005156330A - Distance measuring device and distance monitoring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure a distance to a measuring object with a simple constitution, even in the state where an obstacle such as a waterdrop or dust caused by rainfall or the like exists. <P>SOLUTION: This device has a laser diode 1 for irradiating laser light toward the measuring object D; a reflector 2 installed on the measuring object D for reflecting the laser light; a light receiving element 3 for receiving reflected light reflected by the reflector 2; and an operation processing part 10 for operating the distance to the measuring object D on the basis of the time difference between the point of time when the laser light is irradiated from the laser diode 1 and the point of time when the reflected light is received by the light receiving element 3. Since the sectional area of the laser light is enlarged to a sufficiently larger value than the maximum sectional area of a raindrop by utilizing expansion of the laser light emitted from the laser diode 1, the distance to the measuring object D can be measured even in the state where the obstacle such as the waterdrop or the dust exists. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a distance measuring device that measures a distance to a measurement object using a laser beam, and a distance monitoring system that monitors a distance measured by the distance measuring device.

  Conventionally, various distance measuring apparatuses for measuring a time difference until a laser beam is reflected back to a measurement object and measuring the distance to the measurement object based on the measured time difference are provided. This type of distance measuring device is mounted on a vehicle such as an automobile or a train, and measures the distance to an obstacle (measurement object) such as another vehicle to prevent a collision with the obstacle. It is also used for applications such as monitoring the change in topography by measuring the distance to the target (measurement object) installed on the ground and preventing damage from natural disasters such as earthquakes and landslides ( For example, see Patent Document 1 or Patent Document 2).

By the way, since the measurement object is outdoors when used in the above-described applications, the laser between the distance measurement device and the measurement object depends on weather conditions such as rain, snow, fog, and environmental conditions such as dust. There are cases where the laser beam does not reach the object to be measured due to obstructions such as water droplets or dust existing in the optical path of the light, or the reflected light does not return and accurate measurement may not be possible. Therefore, in the conventional apparatus, a raindrop sensor for detecting raindrops on the optical path is provided, and when the raindrop is detected by the raindrop sensor, the intensity of the laser beam is increased (see Patent Document 1), or the wavelength of the laser beam is increased. It has been practiced to make it sufficiently smaller than the diameter of raindrops (see Patent Document 2).
JP-A-6-308234 Japanese Patent Publication No. 6-80436

  However, the conventional device described in Patent Document 1 has a problem in that since the raindrop sensor is mounted, the configuration becomes complicated, the cost increases, and the external dimensions of the device also increase. In addition, in the conventional apparatus described in Patent Document 2, scattering by an obstacle (such as raindrops) can be suppressed by appropriately setting the wavelength of the laser light, but when the laser light is blocked by the obstacle, There is no change in the point where measurement is not possible.

  The present invention has been made in view of the above circumstances, and the purpose thereof is distance measurement that can measure the distance to an object to be measured with a simple configuration even in the presence of obstacles such as water droplets and dust caused by precipitation. It is to provide an apparatus and a distance monitoring system.

  In order to achieve the above object, the invention of claim 1 includes an irradiating unit that irradiates a measurement target with laser light, a reflecting unit that is installed on the measuring target and reflects the laser light, and a reflecting unit. Light receiving means for receiving the reflected light reflected, and calculation means for calculating the distance to the measurement object based on the time difference between the time when the laser light is irradiated from the irradiation means and the time when the reflected light is received by the light receiving means. And the irradiation means expands the laser light so that the cross-sectional area of the laser light emitted from the light source and the cross-sectional area of the obstacle existing between the object to be measured is larger than the cross-sectional area of the obstacle. It is characterized by having.

  According to this invention, since the laser beam is expanded so that the cross-sectional area is larger than the cross-sectional area of obstacles such as water drops and dust due to precipitation, the laser light is not blocked by the obstacles, Even in the situation where an obstacle exists, the distance to the measurement object can be measured. In addition, since it is only necessary to add means for expanding the laser beam, the configuration is simpler than that of the conventional example, and the external dimensions are not increased.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the irradiating means has the means for expanding the diameter of the laser beam irradiated to the measurement object to 10 mm or more.

  According to the present invention, it is possible to more accurately measure the distance to the measurement object by enlarging the laser beam to a diameter sufficiently larger than rain, fog, or dust particles.

  According to a third aspect of the present invention, in the second aspect of the present invention, the light receiving means includes a light receiving element having a photoelectric conversion function and a lens having a diameter of 10 mm or more and condensing reflected light on the light receiving element. And

  According to the present invention, the reflected light is condensed on the light receiving element by the lens having a diameter sufficiently larger than that of rain, fog, or dust particles, whereby the distance to the measurement object can be measured more accurately.

  According to a fourth aspect of the present invention, in the first, second, or third aspect of the invention, the reflecting means reflects the laser light in substantially the same direction as the incident direction, the light receiving means includes a light receiving element having a photoelectric conversion function, A lens for condensing the reflected light on the light receiving element, and the irradiating means is at least one of the lens for enlarging the laser light, the laser light irradiated to the measurement object, and the reflected light reflected by the reflecting means It has the half mirror which bends one side, It is characterized by the above-mentioned.

  According to the present invention, since the optical path of the laser light emitted from the irradiating means and the optical path of the reflected light reflected by the reflecting means substantially coincide with each other, the reflected light can be collected efficiently and the measurement accuracy and the measurement range can be improved. .

  According to a fifth aspect of the present invention, in the first, second, or third aspect of the invention, the reflecting means reflects the laser light in substantially the same direction as the incident direction, the light receiving means includes a light receiving element having a photoelectric conversion function, A lens for condensing the reflected light on the light receiving element, and the irradiating means is at least one of the lens for enlarging the laser light, the laser light irradiated to the measurement object, and the reflected light reflected by the reflecting means And a prism that bends one side.

  According to the present invention, since the optical path of the laser light emitted from the irradiating means and the optical path of the reflected light reflected by the reflecting means substantially coincide with each other, the reflected light can be collected efficiently and the measurement accuracy and the measurement range can be improved. In addition, the measurement accuracy and the measurement range can be further improved by suppressing the decrease in the amount of light as compared with the case of using the half mirror as in the invention of claim 4.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects of the present invention, the reflecting means comprises a cube mirror.

  According to this invention, even if the incident angle of the laser beam to the reflecting means (cube mirror) changes, the reflected light is reflected in substantially the same direction as the incident direction, so the distance to the measurement object cannot be measured. There is nothing.

  A seventh aspect of the present invention is the light-emitting device according to any one of the first to sixth aspects, wherein the light-receiving means includes a light-receiving element having a photoelectric conversion function, And a light amount adjusting means for adjusting the light amount.

  According to the present invention, the amount of laser light emitted from the irradiation means can be increased without considering the allowable range of the amount of light in the light receiving element. The distance up to is not impossible to measure.

  The invention of claim 8 is the invention according to any one of claims 1 to 7, wherein a housing for accommodating the irradiation means and the light receiving means, a housing for accommodating the housing and the arithmetic means, and a housing in the casing. Supporting means for swingably supporting is provided.

  According to the present invention, since the housing supported by the support means can be maintained as it is without being tilted even if the housing is tilted, the distance to the measurement object is changed by changing the irradiation direction of the laser beam. Can be prevented from becoming impossible to measure.

  According to a ninth aspect of the invention, in any one of the first to third or sixth to eighth aspects of the invention, the irradiating means branches the laser light emitted from the light source into a plurality of laser lights having different directions, and the laser lights are mutually separated. A plurality of measurement objects existing at different distances are irradiated, and the light receiving means receives a plurality of reflected lights respectively reflected by a plurality of reflection means installed on each measurement object, and the calculation means is The distance to each measurement object is calculated according to the order of the plurality of reflected lights received by the light receiving means.

  According to the present invention, the distance to a plurality of measurement objects can be individually measured, and the cost is low and the maintenance labor is reduced compared to a distance measurement apparatus that can measure only the distance to one measurement object. Can be planned.

  According to a tenth aspect of the present invention, in the invention according to any one of the first to third or sixth to eighth aspects, the irradiating means branches the laser light emitted from the light source into a plurality of laser lights having different directions and a plurality of each laser light. The plurality of reflecting means that are respectively irradiated to the measurement object and each of the plurality of measuring objects are linearly polarized reflected lights having different polarization directions, and the light receiving means A polarizing plate placed on the optical path is rotated to selectively receive reflected light in a desired polarization direction.

  According to the present invention, the distance to a plurality of measurement objects can be individually measured, and the cost is low and the maintenance labor is reduced compared to a distance measurement apparatus that can measure only the distance to one measurement object. Can be planned. Moreover, in the invention of claim 9, only the distance to the measurement object existing at different distances can be measured, but in the present invention, it is possible to measure even the distance to the measurement object existing at substantially the same distance, which is excellent in usability.

  In order to achieve the above object, an eleventh aspect of the present invention is directed to the distance measuring device according to any one of the first to tenth aspects, a communication device that transmits a measurement result of the distance measuring device via a communication line, and communication. And a remote monitoring device for holding a measurement result received from a communication device via a line.

  According to the present invention, for example, when monitoring the change in the terrain by monitoring the distance to the measurement object measured by the distance measuring device, the measurement result of the distance measuring device is transmitted to the remote monitoring device using the communication device. Can be used to monitor terrain fluctuations at remote locations away from the location being monitored, saving labor in monitoring work, and responding early to abnormalities (terrain fluctuations). it can.

  According to the present invention, since the laser beam is enlarged so that the cross-sectional area is larger than the cross-sectional area of obstacles such as water droplets and dust due to precipitation, the laser light is not blocked by the obstacles, Even in the presence of obstacles, the distance to the object to be measured can be measured, and it is only necessary to add a means for expanding the laser beam. Therefore, the configuration is simpler and the outer dimensions are larger than the conventional example. There is an effect that it never happens.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a distance measuring apparatus A in the present embodiment, FIG. 2 is a block diagram of an arithmetic processing unit 10 described later, and FIG. 3 is a system configuration diagram of a distance monitoring system in the present embodiment.

  The distance monitoring system of the present embodiment is used for the purpose of monitoring terrain fluctuations for the purpose of preventing damage caused by natural disasters such as earthquakes and landslides, and measures distances as shown in FIG. The apparatus A includes a communication apparatus B that transmits the measurement result of the distance measurement apparatus A via the communication line Ls, and a remote monitoring apparatus C that holds the measurement result received from the communication apparatus B via the communication line Ls. The The communication device B is a conventionally known modem that transmits and receives data via a communication line Ls such as a public telephone line, and is connected to the distance measuring device A by a general-purpose communication interface (such as RS-232C). The remote monitoring device C is constituted by a general-purpose computer device having a built-in modem that transmits and receives data via the communication line Ls, and the measurement result received from the communication device B is stored in a large-capacity storage device (built-in or external hard disk). It can be stored and held in a device, etc., and the measurement result can be referred to as needed according to the operation of the operator, and the operator can be notified when an abnormality (for example, fluctuation of the measurement result due to an earthquake or landslide) occurs. It has become. As described above, since the measurement results of the distance measuring device A can be collected from a remote location, there are advantages in that it is possible to save labor in monitoring work and to quickly cope with the occurrence of an abnormality. It is also possible to transmit a control command from the remote monitoring device C to the distance measuring device A via the communication device B, and to control the operation of the distance measuring device A by the control command.

  On the other hand, the distance measuring apparatus A measures the distance to the measurement object D installed at the measurement point as shown in FIG. 3 and irradiates the measurement object D with laser light 1. And a reflector 2 that is installed on the measuring object D and reflects the laser light, a light receiving element (photodiode) 3 that receives the reflected light reflected by the reflector 2, and a laser beam from the laser diode 1. And an arithmetic processing unit 10 that calculates the distance to the measurement object D based on the time difference between the time when the reflected light is received by the light receiving element 3 and the laser diode 1, the light receiving element 3, and the arithmetic processing unit 10. A housing 20 to be formed, a plano-convex lens provided on the front surface of the housing 20, and an irradiation lens 4 that makes laser light emitted from the laser diode 1 substantially parallel light, and a flat surface that is also provided on the front surface of the housing 20. Convex And a condensing lens 5 for condensing the reflected light consists lens to the light receiving surface of the light receiving element 3. The reflector 2 is formed by applying a white paint on the surface of a plate material, the housing 20 is formed in a rectangular tube shape by a synthetic resin or a metal member, and the irradiation lens 4 and the condenser lens 5 are formed on one end surface (front surface) in the axial direction. Is provided, and a support base 21 protrudes from the side surface (see FIG. 3). Note that lenses other than plano-convex lenses may be used as the irradiation lens 4 and the condenser lens 5.

  The arithmetic processing unit 10 includes a control circuit 11 including a CPU and its peripheral circuits (such as a memory and a clock oscillator), an LD driving circuit 12 that drives the laser diode 1 under the control of the control circuit 11 and emits laser light. Measurement is performed between the signal processing circuit 13 that performs signal processing such as amplification, waveform shaping, and peak hold on the output signal of the light receiving element 3, the timer circuit 14 for managing the date and time, and the communication device B. A general-purpose (RS-232C, etc.) communication interface 15 for sending and receiving results and the like, and a power supply circuit 16 for creating an operating power supply for each circuit using a commercial power supply or a storage battery as a power supply are provided. Thus, the control circuit 11 controls the LD drive circuit 12 to irradiate the pulsed laser light from the laser diode 1 and simultaneously starts counting the internal clock, and reflects the pulsed reflection reflected by the reflector 2. When a received signal after light is received by the light receiving element 3 and processed by the signal processing circuit 13 is input, counting of the internal clock is stopped, and laser light is emitted from the laser diode 1 from the counted number of clocks. A time difference between the time point and the time point when the reflected light is received by the light receiving element 3 is obtained, and the distance to the measurement object D is calculated based on the time difference. Then, the control circuit 11 outputs the measurement result of the distance to the measurement object D to the communication device B via the communication interface 15 and transmits it to the remote monitoring device C through the communication device B.

  By the way, when using red laser light in the visible region, the diameter of the laser light in the conventional example is about 2 mm, but the diameters of raindrops, fog, and dust particles are 0.5 mm to 5 mm, 0.01 mm, and 1 mm, respectively. Therefore, an obstacle (raindrop) having a cross-sectional area larger than the cross-sectional area of the laser light exists on the optical path of the laser light between the distance measuring device A and the measurement object D when it is raining. The laser beam may be blocked by raindrops, making measurement impossible.

  Therefore, in this embodiment, the diameter of the irradiation lens 4 is set to 10 mm or more, which is sufficiently larger than the maximum raindrop diameter, and the laser diode 1 is disposed at the focal point of the irradiation lens 4 so that the laser light emitted from the laser diode 1 is emitted. After expanding the cross-sectional area of the laser beam to a value sufficiently larger than the maximum cross-sectional area of the raindrop using the expansion, the irradiation lens 4 makes the light substantially parallel. At this time, if the laser light emitted from the laser diode 1 has a small divergence angle, and the cross-sectional area of the laser light cannot be sufficiently enlarged at the focal length of the irradiation lens 4, the laser diode 1 and the irradiation lens as shown in FIG. 4, the biconcave lens 6 may be arranged to increase the spread angle of the laser beam.

  Thus, in this embodiment, since the cross-sectional area of the laser light emitted from the laser diode 1 is enlarged as described above, the laser light may be blocked by an obstacle such as raindrops as in the conventional example. In addition, the distance to the measuring object D can be measured even in a situation where an obstacle exists. In addition, since the laser beam is expanded by using the spread of the laser beam emitted from the laser diode 1, the configuration is simpler than the conventional example described in Patent Document 1, and the outer dimensions are large. Nor. In this embodiment, the diameter of the condensing lens 5 is set to 10 mm or more in accordance with the irradiation lens 4, and the reflected light of the laser beam having an enlarged cross-sectional area is efficiently condensed on the light receiving element 3 to be measured. The distance to D can be measured accurately. When the distance measuring device A of this embodiment is installed in a snowfall area, the diameter of snow (including hail and hail) that is an obstacle may reach 150 mm at the maximum, so the irradiation lens 4 and the condenser lens It is desirable that the diameter of 5 is 300 mm or more.

  By the way, if the reflector 2 is made by applying a high reflectivity material such as aluminum on the surface of the plate, or if the surface is mirror-finished, the reflectivity of the reflector 2 and the obstacle with respect to the laser light is different. Therefore, by monitoring the amount of reflected light received by the light receiving element 3 in the arithmetic processing unit 10, it is possible to determine whether the reflected light is due to the reflector 2 or due to an obstacle. Prevention becomes possible. If the reflecting surface (surface) of the reflector 2 is formed in a shape that becomes a part of a spherical surface having a radius of curvature substantially equal to the distance X from the distance measuring device A to the measuring object D as shown in FIG. Even if the incident angle of the laser beam on the reflector 2 changes, the reflected light is reflected in the substantially same direction as the incident direction, and therefore the distance to the measurement object D is not measured.

  Further, since the housing 20 of the distance measuring device A may be shaken by a ground shake by a car traveling on a nearby road or a strong wind, the measurement results may vary. It is desirable that the housing 22 housing the element 3, the irradiation lens 4 and the condenser lens 5 is attached to the housing 20 by the vibration isolating mechanism 23, and the vibration is absorbed by the vibration isolating mechanism 23 to suppress variation in measurement results. . As the vibration isolation mechanism 23, rubber or spring with high internal loss, or an air or hydraulic damper may be used.

  By the way, the distance measuring apparatus A does not always need to perform distance measurement, and may be performed periodically (for example, every several tens of minutes or every several hours) according to a predetermined schedule. If the power is always supplied to the light receiving element 3 or the arithmetic processing unit 10, the power is wasted. Therefore, a distance measurement schedule is registered in the timer circuit 14, and when the time for distance measurement is reached, the timer circuit 14 starts power supply from the power supply circuit 16 to each circuit and completes one distance measurement. If power supply from the power supply circuit 16 to each circuit is stopped, wasteful power consumption can be suppressed.

(Embodiment 2)
In this embodiment, as shown in FIG. 7, the irradiation lens 4 and the condensing lens 5 are used as one plano-convex lens (irradiation / condensing lens) 7, and laser light (irradiation light) emitted from the laser diode 1 is used. The laser beam (reflected light) reflected by the reflector 2 is bent by the half mirror 8, and the other configuration is the same as that of the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and illustration and description thereof are omitted as appropriate.

  The half mirror 8 has a characteristic that the transmittance and the reflectance are each 50% when the incident angle is 45 degrees, and has a dimension capable of covering the condensing range of the irradiation / condensing lens 7, and is a laser diode. The angle formed by one optical axis H1 and the optical axis H2 of the irradiating / condensing lens 7 is arranged to be twice the above angle, that is, 90 degrees. At this time, the light receiving element 3 is disposed at a position where the optical axis H3 coincides with the optical axis H2 of the irradiation / condensing lens 7. Note that the distance on the optical path between the center of the irradiation / condensing lens 7 and the laser diode 1 and the light receiving element 3 is set equal to the focal length of the irradiation / condensing lens 7. In addition, the reflector 2 is configured to reflect the laser light in substantially the same direction as the incident direction.

  Thus, according to the present embodiment, since the optical path of the irradiation light irradiated from the laser diode 1 and the optical path of the reflected light reflected by the reflector 2 substantially coincide, the reflected light can be efficiently collected and measured. There is an advantage that accuracy and measurement range can be improved.

(Embodiment 3)
By the way, in the structure of Embodiment 2, since neither irradiation light nor reflected light is parallel light, the transmittance | permeability differs depending on the place which injects into the half mirror 8, and it may be difficult to perform stable distance detection.

  Therefore, in the present embodiment, as shown in FIG. 8, a plano-convex lens 30 is arranged between the laser diode 1 and the half mirror 8 to convert the irradiation light incident on the half mirror 8 into parallel light, and further to the half mirror 8 and irradiation. The irradiation light is magnified by the biconcave lens 31 disposed between the condenser lenses 7 and the plano-convex lens 32 is disposed between the light receiving element 3 and the half mirror 8 so that the reflected light transmitted through the half mirror 8 is received by the light receiving element 3. The light is collected on the light receiving surface. In addition, since it is the same as that of Embodiment 1 and 2 about other structures, the same code | symbol is attached | subjected to a common component and illustration and description are abbreviate | omitted suitably.

  Thus, in the present embodiment, since the irradiation light and the reflected light incident on the half mirror 8 are both parallel light, there is no difference in transmittance depending on the location incident on the half mirror 8, and stable distance detection is possible. It can be performed. Further, since the half mirror 8 does not need to have a size that can cover the condensing range of the irradiation / condensing lens 7, there is an advantage that cost reduction can be achieved by downsizing the half mirror 8.

(Embodiment 4)
In this embodiment, as shown in FIG. 9, the laser light (irradiation light) emitted from the laser diode 1 and the laser light (reflected light) reflected by the reflector 2 are bent as means for bending the half mirror 8. The configuration is characterized in that the polarizing prism 9 is used, and the other configurations are the same as those in the first to third embodiments. Therefore, the same code | symbol is attached | subjected to the same component as Embodiment 1-3, and illustration and description are abbreviate | omitted suitably.

  In the present embodiment, as shown in FIG. 9, the polarizing prism 9 and the quarter-wave plate 24 are disposed at the position of the half mirror 8 in the third embodiment. The polarizing prism 9 has an entrance surface 9a and an exit surface 9b adjacent to each other, and an entrance / exit surface 9c opposite to both the entrance surface 9a and the exit surface 9b. The convex lens 30 is disposed, the light receiving element 3 and the plano-convex lens 31 are disposed at a position facing the exit surface 9b, and the quarter-wave plate 24 is disposed at a position facing the entrance / exit surface 9c.

  Thus, if the laser light emitted from the laser diode 1 is linearly polarized light and has a polarization plane parallel to the arrow in FIG. 10A, the polarized light is converted into parallel light by the plano-convex lens 30. Irradiation light incident from the incident surface 9a of the prism 9 and emitted from the incident / exit surface 9c passes through the quarter-wave plate 24, and the polarization plane is counterclockwise as shown in FIG. It will rotate 45 degrees. When the light is reflected by the reflector 2, the polarization plane does not rotate (see FIG. 10C), but when the reflected light passes through the quarter-wave plate 24, it is shown in FIG. As shown, the plane of polarization rotates 45 degrees counterclockwise. As a result, the polarization plane (see FIG. 10A) of the irradiation light emitted from the entrance / exit surface 9c of the polarization prism 9 and the polarization plane of the reflected light incident on the entrance / exit surface 9c of the polarization prism 9 (FIG. 10D). ) Is 90 degrees.

  On the other hand, the polarizing prism 9 emits the incident light incident from the incident surface 9a without being refracted, and is emitted from the incident / exit surface 9c. Therefore, the light is refracted by a predetermined angle and emitted from the emission surface 9b. That is, the polarized light is bent by the polarizing prism 9 by shifting the polarization planes of the irradiation light and the reflected light by the quarter wavelength plate 24.

  As described above, since the reflected light is bent using the polarizing prism 9 in the present embodiment, the decrease in the amount of light can be suppressed compared to the case where the irradiation light is bent using the half mirror 8 as in the third embodiment. There is an advantage that the measurement accuracy and the measurement range can be improved.

(Embodiment 5)
The present embodiment is characterized in that a cube mirror 25 is used as the reflecting means, and other configurations are the same as those in the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and illustration and description thereof are omitted as appropriate.

  The cube mirror 25 is well known in the art, and combines a prism and a reflecting mirror to reflect light in the original direction regardless of the incident direction. As shown in FIG. Thus, the light incident from the ABC surface in the figure is reflected once by the three reflecting surfaces and exits from the ABC surface again.

  Thus, if the cube mirror 25 is used as the reflecting means, the reflected light is reflected in substantially the same direction as the incident direction even if the incident angle of the laser beam to the cube mirror 25 changes as shown in FIG. For this reason, the distance to the measurement object D does not become unmeasurable.

  In addition, as shown in FIG.11 (c), you may use what arranged many cube mirrors 25 on the same plane as a reflection means. In this case, it is desirable that the size of each cube mirror 25 is 1/10 or less of the diameter of the irradiation light.

(Embodiment 6)
This embodiment is characterized in that a light amount adjusting means 26 for adjusting the amount of reflected light is provided between the light receiving element 3 and the condenser lens 5 as shown in FIG. It is common. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and illustration and description thereof are omitted as appropriate.

  For example, the light amount adjusting unit 26 is configured to make the light transmittance variable by mechanically replacing a liquid crystal shutter having a variable light transmittance or a plurality of ND filters having different densities.

  Thus, if the light amount adjusting means 26 adjusts the light amount of the reflected light to be within the allowable range of the light receiving element 3, the laser light emitted from the laser diode 1 without taking into consideration the allowable range of the light amount in the light receiving element 3. Since the amount of light can be increased, it is possible to prevent the distance to the measurement object D from becoming unmeasurable due to a decrease in the S / N ratio caused by the obstacle.

(Embodiment 7)
Since the basic configuration of the present embodiment is the same as that of the first embodiment, common components are denoted by the same reference numerals, and illustration and description thereof are omitted as appropriate, and only the configuration that is a feature of the present embodiment will be described.

  In the present embodiment, as shown in FIG. 13A, a plurality of housings 22 each housing a laser diode 1, a light receiving element 3, an irradiation lens 4, and a condenser lens 5 are fixed to the top surface of the housing 20. It is characterized in that it is suspended by a wire 27 and supported in a swingable manner within the housing 20.

  Thus, in this embodiment, the housing 22 supported by the wire 27 serving as the support means can be held without being tilted even when the housing 20 is tilted, and therefore the irradiation direction of the laser light changes. Therefore, it is possible to prevent the distance to the measurement object D from being disabled.

  In the present embodiment, the wire 27 is used as the supporting means. However, as shown in FIG. 13B, a hinge 28 attached to the top surface of the housing 20 and a housing 22 that is suspended from the hinge 28 and is attached to the tip. You may comprise a support means with the support | pillar 29 attached.

  Further, instead of suspending the housing 22 from the housing 20 by the supporting means such as the wire 27, as shown in FIG. 13C, the housing 22 protrudes from a position vertically above the center of gravity G of the housing 22 on the side surface of the housing 22. The rotating shaft (not shown) is pivotally supported by a bearing portion 41 provided at the front end portion of the support base 40 erected from the bottom surface of the housing 20 to support the support base 40 and the rotation shaft. Thus, the housing 22 may be swingably supported. When such a support structure is employed, there is an advantage that the housing 20 can be easily downsized because the swing range (swing radius) is smaller than that of the above-described suspension structure. In addition, there is an advantage that shaking of the housing 22 is suppressed when the housing 20 vibrates due to the frictional force generated between the rotating shaft and the bearing portion 41.

(Embodiment 8)
Since the basic configuration of the present embodiment is the same as that of the first embodiment, common components are denoted by the same reference numerals, and illustration and description thereof are omitted as appropriate, and only the configuration that is a feature of the present embodiment will be described.

  In the present embodiment, the laser light emitted from one laser diode 1 is branched into a plurality of laser beams having different directions, and each measurement object is irradiated with each laser beam at different distances. A plurality of reflected lights respectively reflected by a plurality of reflecting means installed on the light receiving element 3 are received by one light receiving element 3, and the arithmetic processing unit 10 performs each measurement according to the order of the plurality of reflected lights received by the light receiving element 3. It is characterized in that the distance to the object is calculated.

As shown in FIG. 14, the laser diode 1 is disposed in a direction of irradiating the incident surface parallel to the laser beam irradiation lens 4, the first to fifth half mirror 42 _{1-42 5} laser transmittance are different from each other They are arranged in a line on the optical axis of the diode 1. In this embodiment, first to fifth half mirror 42 _{1-42 5} transmittance of 80% each of 75%, 66%, 50% and 0%, a half mirror 42 of the first to 51 _to 42 ₅ each illumination light into parallel light by the irradiation lens 4 is reflected by the is set to be 20% of the amount of the original laser beam (intensity).

A plurality of irradiation lights branched in this way are irradiated to corresponding measurement objects (not shown), and the reflected light reflected by the reflectors installed on the measurement objects is received by the light receiving element 3. Will be. That is, when the pulsed irradiation light as shown in FIG. 15A is irradiated from the laser diode 1, a plurality of irradiation light beams corresponding to the respective irradiation lights branched by the _{first to fifth} half mirrors 42 _{1 to} 425 are used. As shown in FIG. 15B, the timing at which the reflected lights R1 to R5 are received by the light receiving element 3 is earlier as the distance to each measurement object is shorter. Here, since the distances to the individual measurement objects are known in advance, the reflected lights R1 to R5 received at different timings in the arithmetic processing unit 10 (control circuit 11) are reflected light from any measurement object. It is possible to determine the distance to each measurement object.

  Thus, in this embodiment, it is possible to individually measure the distances to a plurality of measurement objects, which is lower in cost and maintenance than a distance measurement device that can measure only the distance to one measurement object. There is an advantage that labor saving can be achieved.

(Embodiment 9)
Since the basic configuration of the present embodiment is the same as that of the first embodiment, common components are denoted by the same reference numerals, and illustration and description thereof are omitted as appropriate, and only the configuration that is a feature of the present embodiment will be described.

  In the present embodiment, a laser beam emitted from one laser diode 1 is branched into a plurality of laser beams having different directions, and each of the laser beams is irradiated to a plurality of measurement objects at different distances, thereby Each laser beam is converted into linearly polarized reflected light with a different polarization direction by the reflecting means installed on the object, and the reflected light with the desired polarization direction is selected by rotating the polarizing plate installed on the optical path of the reflected light. In particular, the light receiving element 3 receives light. However, since the configuration for branching the laser beam into a plurality of laser beams is the same as that in the eighth embodiment, the description thereof is omitted.

Reflecting means installed in a plurality of measurement object consists of a reflective polarizer 43 _{1-43 3} of the rectangular plate shape as shown in FIG. 16. Laser light from the laser diode 1 is emitted to a linearly polarized light, reflected in Figure 17 When those having arrow parallel to the plane of polarization of (a) (polarization direction), these polarization reflector 43 _{1-43 3} As shown in FIGS. 17B to 17D, the respective reflected lights have their polarization planes rotated 45, 90, and 135 degrees counterclockwise.

  On the other hand, a substantially circular polarizing plate 50 is rotatably disposed in front of the light receiving element 3 as shown in FIG. A large number of teeth (not shown) are arranged on the peripheral surface of the polarizing plate 50, and a gear 51 that meshes with these teeth is attached to a motor shaft 52 a of the servomotor 52. The servo motor 52 is controlled by the motor controller 53 in the direction and amount of rotation. That is, the servo motor 52 is controlled by the motor controller 53 to rotate the polarizing plate 50, and the polarization plane of the polarizing plate 50 is set to the polarization plane of any one of the plurality of reflected lights having different polarization planes. By matching, reflected light in a desired polarization direction can be alternatively received by the light receiving element 3. Note that which reflected light is selected is controlled by controlling the motor controller 53 from the control circuit 11.

  Thus, in this embodiment, it is possible to individually measure the distances to a plurality of measurement objects, which is lower in cost and maintenance than a distance measurement device that can measure only the distance to one measurement object. Labor saving can be achieved. In addition, in the eighth embodiment, only distances to measurement objects existing at different distances can be measured. However, in this embodiment, measurement is possible even at distances to measurement objects existing at substantially the same distance, which is excellent in usability. is there.

It is a schematic block diagram which shows the distance measuring device in Embodiment 1. It is a block diagram of the arithmetic processing part in a distance measuring device same as the above. It is a system configuration figure showing a distance monitoring system same as the above. It is a schematic block diagram which shows the other structure of the principal part in a distance measuring apparatus same as the above. It is a schematic block diagram which shows the other structure of a distance measuring apparatus same as the above. It is a schematic block diagram which shows the internal structure of a distance measuring apparatus same as the above. It is a schematic block diagram which shows the principal part of the distance measuring device in Embodiment 2. It is a schematic block diagram which shows the principal part of the distance measuring device in Embodiment 3. It is a schematic block diagram which shows the principal part of the distance measuring device in Embodiment 4. It is operation | movement explanatory drawing same as the above. (A) is a perspective view of the reflection means (cube mirror) in Embodiment 5, (b) is operation | movement explanatory drawing of Embodiment 5, (c) is a perspective view which shows the other structure of a reflection means. It is a schematic block diagram which shows the principal part of the distance measuring device in Embodiment 6. (A) is a schematic block diagram which shows the internal structure of the distance measuring device in Embodiment 7, (b) is a schematic block diagram which abbreviate | omitted one part which showed the other internal structure of the distance measuring device, (c) is a distance measuring device. It is a schematic block diagram which shows another internal structure. It is a schematic block diagram which shows the principal part of the distance measuring device in Embodiment 8. It is operation | movement explanatory drawing same as the above. It is a schematic block diagram which shows the principal part of the distance measuring device in Embodiment 9. It is operation | movement explanatory drawing same as the above. It is a schematic block diagram which shows the principal part of the distance measuring device same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser diode 2 Reflector 3 Light receiving element 4 Irradiation lens 5 Condensing lens 10 Arithmetic processing part

Claims (11)

  From irradiation means for irradiating laser light toward the measurement object, reflection means for reflecting the laser light installed on the measurement object, light receiving means for receiving the reflected light reflected by the reflection means, and irradiation means Computation means for computing the distance to the measurement object based on the time difference between the time when the laser light was irradiated and the time when the reflected light was received by the light receiving means, and the irradiation means, a light source that emits the laser light, A distance measuring apparatus comprising: means for expanding the laser light so that a cross-sectional area of the laser light emitted from the light source is larger than a cross-sectional area of an obstacle existing between the object and the object to be measured.   2. The distance measuring apparatus according to claim 1, wherein the irradiating means includes the means for expanding the diameter of the laser beam irradiated to the measurement object to 10 mm or more.   The distance measuring device according to claim 2, wherein the light receiving means includes a light receiving element having a photoelectric conversion function and a lens having a diameter of 10 mm or more and collecting reflected light on the light receiving element.   The reflecting means reflects the laser light in substantially the same direction as the incident direction, the light receiving means has a light receiving element having a photoelectric conversion function, and a lens for condensing the reflected light on the light receiving element, and the irradiation means is The lens for enlarging a laser beam, and a half mirror that bends at least one of the laser beam irradiated to the measurement object and the reflected beam reflected by the reflecting means. The distance measuring device according to 2 or 3.   The reflecting means reflects the laser light in substantially the same direction as the incident direction, the light receiving means has a light receiving element having a photoelectric conversion function, and a lens for condensing the reflected light on the light receiving element, and the irradiation means is 3. The lens for enlarging a laser beam, and a prism for bending at least one of the laser beam irradiated to the measurement object and the reflected beam reflected by the reflecting means. Or the distance measuring device of 3.   6. The distance measuring device according to claim 1, wherein the reflecting means is a cube mirror.   The light receiving means includes a light receiving element having a photoelectric conversion function and a light amount adjusting means for adjusting a light amount of the reflected light so that the light amount of the reflected light is within an allowable range of the light receiving element. 6. The distance measuring device according to any one of 6 above.   A housing for housing the irradiation means and the light receiving means, a housing for housing the housing and the computing means, and a supporting means for swingably supporting the housing within the housing. The distance measuring device according to any one of 1 to 7.   The irradiating means divides the laser beam emitted from the light source into a plurality of laser beams having different directions and irradiates each laser beam to a plurality of measuring objects existing at different distances. The plurality of reflected lights respectively reflected by the plurality of reflecting means installed on the object are received, and the computing means is a distance to each measurement object according to the order of the plurality of reflected lights received by the light receiving means. The distance measuring device according to any one of claims 1 to 3 or 6 to 8, wherein   The irradiation means divides the laser beam emitted from the light source into a plurality of laser beams having different directions and irradiates each of the plurality of measurement objects with a plurality of reflections respectively installed on the plurality of measurement objects. The means converts each laser beam into a linearly polarized reflected light having a different polarization direction, and the light receiving means rotates a polarizing plate installed on the optical path of the reflected light to selectively reflect the reflected light in a desired polarization direction. The distance measuring device according to claim 1, wherein the distance measuring device receives light.   11. The distance measuring device according to claim 1, a communication device that transmits a measurement result of the distance measuring device via a communication line, and a remote that holds a measurement result received from the communication device via the communication line A distance monitoring system comprising a monitoring device.

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