JPH0868852A - Electrooptical distance measuring equipment - Google Patents

Abstract

PURPOSE: To enhance accuracy in the measurement of distance, along with the vibration resistance and cost, by disposing a switching shade in front of a quantity of light attenuator on the light receiving side. CONSTITUTION: A distance measuring luminous flux L0 is emitted from a light emitting element 1 and split prism 2 into a distance measuring light L1 and a reference light LR. The reference light LR passes through relay lenses 8, 9 and impinges on a shade 10. The distance measuring light L1 is reflected on a right angle mirror 3 and directed toward an object through an objective lens 4. The distance measuring light L1 is reflected on the surface of the object while being diffused and directed toward an electrooptical distance measuring equipment 15. The reflected distance measuring light L2 passes through a lens 4, further, is reflected on the mirror 3 and impinges on the switching shade 10. The shade 10 switches the optical path to pass the reflected distance measuring light L2 and the reference light LR alternately. When the reference light LR is intercepted, the reflected distance measuring light L2 passes through a quantity of light attenuator 7, a bandpass filter 14 and a split prism 5 and impinges on a light receiving element 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightwave distance meter equipped with a light amount attenuator for adjusting the amount of reflected distance measuring light received from a distance measuring object and for obtaining a distance from the adjusted distance measuring reflected light and reference light. .

[0002]

2. Description of the Related Art FIG. 5 shows a conventionally used lightwave rangefinder, and FIG. 2 shows a lightwave rangefinder developed by the present applicant.

The lightwave rangefinder shown in FIG. 5 is conventionally used as a prism lightwave rangefinder.
0, the light emitting element 31, the right angle mirror 33, the objective lens 34,
A bandpass filter 35, a light receiving element 36, a light quantity attenuator 37, etc. are provided.

An optical distance meter 20 developed by the present applicant and shown in FIG.
Is a non-prism optical rangefinder. This lightwave rangefinder 2
No. 0 is capable of distance measurement using the reflection prism 21 as the prism light wave distance meter, and at the same time, the reflection prism 2
Even without using 1, the distance can be measured by the distance measurement reflected light L2 from the distance measurement object.

The light wave distance meter 20 includes a light emitting element 1, a first split prism 2, a right angle mirror 3, an objective lens 4, a second split prism 5, a light receiving element 6, a light quantity attenuator 7, a first relay lens 8 and a second relay lens 8. Relay lens 9, light shield 11, hand pass
The filter 14 etc. are provided.

Next, referring to FIG. 3, this lightwave rangefinder 20
The distance measurement by will be described.

This light wave range finder 20 usually has a reflecting prism 21 (also called a reflecting mirror) as a distance measuring object.
Is placed on the distance measurement target.

Then, the distance measuring light L1 is emitted from the optical distance meter 20 toward the reflecting prism 21, and the reflecting prism 21
The reflected light is received by the lightwave distance meter 20.
Thereby, the distance from the lightwave rangefinder 20 to the reflection prism 21 is measured. This distance can be the distance from the lightwave rangefinder 20 to the distance measurement target.

Next, the distance measurement will be described in more detail with reference to FIG.

The light emitting element 1 emits the distance measuring light beam L0 to the first light beam.
Light is emitted toward the split prism 2. Luminous flux for distance measurement L0
Is a constant pulsed light.

Distance measuring light beam L0 emitted from the light emitting element 1.
Goes through the first split prism 2,
1 and the reference light LR.

A switching type light shield plate 11 is provided on the exit side of the first split prism 2. The distance measuring light L1 and the reference light LR are alternately output by the light shielding plate 11. That is, the distance measuring light L1 and the reference light LR are alternately shielded by the light shielding plate 11.

Reference light LR output by the light shielding plate 11
Passes through the first relay lens 8 and the second relay lens 9, is further reflected by the second split prism 5, and enters the light receiving element 6.

Distance measuring light L1 output by the light shielding plate 11
Is reflected by the right-angled mirror 3 and then passes through the objective lens 4 to be reflected by the reflecting prism 2 arranged at the distance measuring target.
It is ejected toward 1.

A reflecting prism 21 arranged at a distance measuring target.
Will retroreflect all light fluxes that have entered it. Therefore, the distance measuring light L1 that has entered the reflecting prism 21 is retroreflected and travels to the optical distance meter 20. Hereinafter, the reflected light traveling toward the lightwave range finder 20 will be referred to as distance measurement reflected light L2.

The distance-measuring reflected light L2 enters the objective lens 4, is reflected by the rectangular mirror 3, and then enters the light receiving element 6 through the light quantity attenuator 7, the bandpass filter 14 and the second split prism 5 in this order.

As described above, the distance measuring light L1 and the reference light LR are provided by the light shielding plate 11 arranged on the light emitting side of the light distance meter 20.
Are switched, and the distance measurement reflected light L2 and the reference light LR are alternately incident on the light receiving element 6.

The lightwave distance meter 20 determines the distance between the lightwave distance meter 20 and the reflection prism 21 from the phase shift of the distance measurement reflected light L2 incident on the light receiving element 6 and the reference light LR. Therefore, in principle, the distance can be measured regardless of the respective intensities of the distance measurement reflected light L2 and the reference light LR.

However, in general, the characteristics of the light receiving element 6 have a phase change depending on the intensity of light incident thereon,
Not constant. Therefore, when the intensity of the distance measurement reflected light L2 and the reference light LR entering the light receiving element 6 are different from each other, the measurement accuracy is likely to deteriorate.

In order to prevent this, particularly in the case of distance measurement requiring accuracy, the intensity of the distance measurement reflected light L2 and the intensity of the reference light LR incident on the light receiving element 6 are made equal to each other. That is, the light amount attenuator 7 that makes the intensity of the distance measurement reflected light L2 incident on the light receiving element 6 constant is provided on the light receiving optical system side.

For example, the reflection prism 21 is a lightwave rangefinder 2
If it is relatively far from 0 (hereinafter referred to as long-distance measurement),
The light amount attenuator 7 adjusts the distance measurement reflected light L2 so as to be transmitted more, and conversely, when the distance measurement reflected light L2 is relatively close (hereinafter, referred to as short distance measurement), is adjusted so as to be less transmitted.

Explaining the reason therefor, in the case of long-distance measurement, the distance measurement reflected light L2 from the reflection prism 21 is
This is because it is weaker than the case of short-range measurement. In this way, the light amount attenuator transmits a large amount of light in long-distance measurement, so that the influence of ambient light on the measurement accuracy is likely to be strong.
However, the effect of ambient light is not so strong that it becomes a substantial problem. The ambient light referred to here is a light wave other than the distance measurement reflected light L2, such as the sunlight S and its reflected light.

This point will be described in detail below with reference to FIG. By the retroreflection of the reflection prism 21,
All the ambient light including the extremely strong ambient light such as the sunlight S is reflected in the direction opposite to the incident direction and is not reflected toward the optical rangefinder 20. That is, the ambient light does not enter within the objective incident solid angle of the optical distance meter 20. Therefore, the ambient light hardly enters the light receiving element 6, and the measurement accuracy is not adversely affected.

In the short-distance measurement, if the background of the distance measuring target is like a white wall reflecting a lot of light, ambient light is incident on the light receiving element 6 to some extent. However, since the incident ambient light is much weaker than the distance measurement reflected light L2, the influence of the ambient light on the measurement accuracy is:
It's not really strong enough to be a problem.

As described above, when the reflecting prism 21 is used, the measurement accuracy is good.

In addition to such a light wave range finder, a non-prism light wave range finder capable of measuring a distance without using a reflecting prism has been conventionally used.

The lightwave distance meter 20 shown in FIG. 2 is an optical system used in the non-prism lightwave distance meter as described above.

Referring to FIG. 4, the lightwave rangefinder 2 will be described.
When 0 is used as a non-prism optical distance meter, the surface of the distance measurement object 23 is used as the distance measurement object without using the reflection prism. That is, the distance measuring light L1 is reflected on the surface and the reflected light is received.

However, unlike the reflection prism, the object 23 for distance measurement normally does not have a high reflectance and diffuses and reflects light.

Therefore, the distance measuring light L1 incident on the surface of the distance measuring object 23 is diffusely reflected. FIG. 4 schematically shows the state of this diffuse reflection DR.

When performing distance measurement with a non-prism, the light wave distance meter 20 uses stronger pulsed light as the distance measuring light L1 than in the case of using the above-mentioned reflection prism. However, due to the diffuse reflection described above, the amount of the distance measurement reflected light L2 entering the light amount attenuator is small.

Therefore, when distance measurement is performed with a non-prism, the light wave range finder 20 adjusts the light amount attenuator so as to transmit a larger amount of the distance measurement reflected light L2 as compared with the case where the above-described reflection prism is used. .

However, ambient light such as sunlight S that has entered the surface of the object 23 to be measured is also diffusely reflected. A part of the ambient light DL is directed toward the optical distance meter 20. The disturbance light DL is received by the optical distance meter 20 together with the distance measurement reflected light L2, and is transmitted through the light amount attenuator 7. That is, the light amount attenuator 7 attenuates the distance reflection light L2 by the same ratio.

Therefore, in both short-distance measurement and long-distance measurement, a large amount of disturbance light passes through the light quantity attenuator as compared with the above-described light wave distance meter using the reflection prism.
In particular, in the non-prism reachable limit measurement, a large amount of ambient light (mainly sun rays in the field).

The light transmitted through the light quantity attenuator is S / N separated by a bandpass filter. That is, the distance measurement reflected light L2 and the ambient light DL are separated, and the distance measurement reflected light L
Only 2 is incident on the light receiving element. Thereby, the ambient light D
The adverse effect of L is reduced.

However, in reality, the S / N separation cannot be completely performed, so that the adverse effect of the ambient light DL cannot be completely eliminated.

[0037]

In the above-described prism lightwave rangefinder shown in FIG. 5 and the lightwave rangefinder 20 using the optical system shown in FIG. When the sunlight S enters the light distance meter 20, or when the background of the distance measurement target is like a white wall that reflects a lot of light, the amount of light entering the light attenuators 7, 37 increases. In addition, there is a possibility that a film or the like which adjusts the degree of light shielding in the light quantity attenuators 7 and 37 by condensing may be burnt. In order to prevent this, the light quantity attenuators 7 and 37 have a structure in which the film or the like is sandwiched by heat-resistant glass or the like to prevent air from entering the inside, thereby preventing oxidation, that is, burning. . Moreover, since the influence of the ambient light is not so strong as to cause a problem, the arrangement of the light shielding plate 11 is not limited.

However, the light quantity attenuator 7 made of glass or the like is disadvantageous in terms of vibration resistance and cost.

Further, in the above-described distance measurement by the non-prism, even when the reference light LR is output by the light shielding plate, the disturbance light DL passes through the light quantity attenuator and enters the light receiving element. That is, ambient light noise is mixed in the reference light measurement. As a result, the problem that S / N decreases and the measurement accuracy decreases is likely to occur.

Moreover, the disturbance light DL is transmitted through the light quantity attenuator at all times, that is, not only when the distance measuring light L1 is output, but also when the reference light LR is output. The light intensity attenuator is likely to be burnt or deformed by heat.

Also, in the conventional optical distance meter shown in FIG. 5, the same problem as in the non-prism optical distance meter occurs.

It is an object of the present invention to provide an optical distance meter capable of improving the measurement accuracy, vibration resistance and cost.

[0043]

In order to solve the above-mentioned problems, the first invention of the present application is provided with a light amount attenuator for adjusting the light amount of the distance measurement reflected light received from the distance measuring object, and is adjusted. A gist of a light wave range finder, in which a switching type light shielding plate is arranged on a light receiving side and in front of a light quantity attenuator, in a light wave range finder for obtaining a distance from reflected light for distance measurement and reference light.

Further, the second invention of the present application is provided with a light amount attenuator for adjusting the light amount of the distance measuring reflected light received from the distance measuring object, and the light wave distance for obtaining the distance from the adjusted distance measuring reflected light and the reference light. In the meter, a switching type light shield plate is used on the light receiving side.
In addition, a gist of a lightwave distance meter, which is arranged in front of a light quantity attenuator and which alternately switches an optical path of distance measuring light and an optical path of reference light by a light shielding plate.

[0045]

EXAMPLE An optical distance meter according to an example of the present invention will be described.

The present invention relates to an optical wave range finder, and more particularly to a non-prism optical range finder capable of measuring a distance without using a reflecting prism. The non-prism lightwave rangefinder measures the distance based on the light reflected by the distance measurement target.

The optical distance meter of the present invention is provided with a light quantity attenuator for adjusting the light quantity of the distance measuring reflected light received from the distance measuring object, and the light wave distance meter for obtaining the distance from the adjusted distance measuring reflected light and the reference light. Is.

In the present invention, the switching type light shield plate is
It is placed on the light receiving side and in front of the light intensity attenuator.

Further, a lightwave distance meter according to another aspect of the present invention includes a light amount attenuator for adjusting the light amount of the distance measurement reflected light received from the distance measurement target, and is adjusted from the adjusted distance measurement reflected light and the reference light. A light-wave rangefinder for determining a distance, in which a switching type light blocking plate is arranged on the light receiving side and in front of the light amount attenuator, and the light blocking plate alternately switches the optical path of the distance measuring light and the optical path of the reference light.

Illustrative Example Next, the optical distance meter according to the illustrative example shown in FIG. 1 will be described.

Referring to FIG. 1, this lightwave rangefinder includes a light emitting element 1, a first split prism 2, a right angle mirror 3, an objective lens 4, a second split prism 5, a light receiving element 6, a light quantity attenuator 7, and a first light splitting element. The relay lens 8, the second relay lens 9, the light blocking plate 10, and the bandpass filter 14 are provided. These can be the same as the conventional ones except for the light shielding plate 10. In the illustrated example, the same reference numerals as those in FIG. 2 described above are attached except the light shielding plate 10.

The right-angle mirror 3 and the objective lens 4 are composed of light emitting side portions 3a and 4a and light receiving side portions 3b and 4b, respectively.

As the light quantity attenuator 7, an ND filter or the like can be used.

As the band-pass filter 14, an ordinary S / N separation means such as an infrared filter for cutting visible light can be adopted.

The light emitting element 1, the first split prism 2, the light emitting side portion 3a of the right angle mirror 3, and the light emitting side portion 4 of the objective lens 4.
a, the first relay lens 8 constitutes a light emitting optical system 12. The light receiving side portion 3b of the right-angled mirror 3, the light receiving side portion 4b of the objective lens 4, the second split prism 5, the light receiving element 6, the light amount attenuator 7, the second relay lens 9, the light shielding plate 10, and the bandpass filter 14 receive the light. The optical system 13 is configured.

The light emission optical system 12 is arranged on the light emission side of the light wave range finder. The light receiving optical system 13 is arranged on the light receiving side of the optical distance meter.

Next, the distance measurement by the lightwave distance meter 15 will be described with reference to FIG.

First, the light emitting element 1 has the distance measuring light beam L0.
Emits light. The distance measuring light beam L0 is a constant pulsed light.

The distance measuring light beam L0 emitted from the light emitting element 1 is split into the distance measuring light L1 and the reference light LR by passing through the first splitting prism 2.

The reference light LR enters the light shielding plate 10 via the first relay lens 8 and the second relay lens 9.

The distance measuring light L1 is reflected by the light emitting side portion 3a of the right-angled mirror 3 and the light emitting side portion 4a of the objective lens 4.
And becomes a parallel light flux, which is emitted toward the object 23 for distance measurement.

Similar to the above-mentioned conventional non-prism optical distance meter, the surface of the distance measuring object 23 is used as the distance measuring object.

Distance measuring light L incident on the surface of the distance measuring object 23
1 is diffused and reflected toward the optical distance meter 15 as described later. Hereinafter, the reflected light traveling toward the lightwave range finder 15 is referred to as distance measurement reflected light L2.

The distance-measuring reflected light L2 passes through the light-receiving side portion 4b of the objective lens 4, is reflected by the light-receiving side portion 3b of the rectangular mirror 3, and enters the switchable light-shielding plate 10. The switching method here is understood in a broad sense and refers to all methods for switching between the light-shielded state and the non-light-shielded state.

The optical path of the distance measurement reflected light L2 and the optical path of the reference light LR are switched by the switching type light shielding plate 10, and the distance measurement reflected light L2 and the reference light LR are alternately input. That is, the light blocking plate 10 alternately blocks the optical path of the distance measurement reflected light L2 and the optical path of the reference light LR. As the light shielding plate 10, a chopper or the like used in a conventional optical distance meter can be adopted.

When the distance measurement reflected light L2 is blocked and the reference light LR is output, the output reference light LR enters the light receiving element 6 through the second split prism 5.

When the distance measurement reflected light L2 is output and the reference light LR is blocked, the distance measurement reflected light L2 passes through the light amount attenuator 7, the bandpass filter 14 and the second split prism 5 in this order, and then the light receiving element 6 is received. Incident on.

In this way, the distance measuring reflected light L2 is obtained by the light shielding plate 10 arranged in the light receiving optical system 13 of the light distance meter 15.
And the optical path of the reference light LR are switched, and the distance measurement reflected light L2 and the reference light LR enter the light receiving element 6 alternately.

The light-wave distance meter 15 obtains the distance between the light-wave distance meter 15 and the distance-measuring object 23 from the phase shift between the distance-measuring reflected light L2 and the reference light LR incident on the light receiving element 6. Therefore, on the measurement principle, the distance can be measured regardless of the intensities of the distance measurement reflected light L2 and the reference light LR.

However, the characteristics of the light receiving element 6 change depending on the intensity of light and are not constant. Therefore, when the intensity of the distance measurement reflected light L2 and the reference light LR entering the light receiving element 6 are different from each other, the measurement accuracy is likely to deteriorate.

In order to prevent this, particularly in the case of distance measurement requiring accuracy, the intensity attenuator 7 adjusts the intensity of the distance measurement reflected light L2 so that the distance measurement reflected light incident on the light receiving element 6 is adjusted. The strength of L2 and the strength of the reference light LR are made equal to each other.

For example, the distance measuring object 23 is the lightwave range finder 15.
When the distance is relatively far from (hereinafter, referred to as long distance measurement), the light amount attenuator 7 adjusts so that a large amount of the distance measurement reflected light L2 is transmitted, and conversely, when relatively relatively (hereinafter referred to as short distance measurement). Adjusted to be less transparent.

The lightwave distance meter 15 of the present invention uses a strong pulsed light as the distance measuring light L1 as compared with the case where the conventional reflection prism described above is used.

However, the reflectance of the surface of the distance measuring object 23 is usually lower than the reflectance of the reflecting prism, and the distance measuring light L1 incident on the surface of the distance measuring object 23 is diffusely reflected. FIG. 4 schematically shows the state of this diffuse reflection DR.

Due to this diffuse reflection, the lightwave rangefinder 1 is different from the conventional lightwave rangefinder using the above-mentioned reflection prism.
The light amount of the distance measurement reflected light L2 received by 5 is small.

Therefore, the light quantity attenuator 7 is adjusted so as to transmit a large amount of the distance measurement reflected light L2 as compared with the conventional light distance meter using the above-mentioned reflection prism.

The sunlight S incident on the surface of the distance measuring object 23
The ambient light such as is diffusely reflected, and a part of the ambient light DL
Heads towards the lightwave rangefinder 15. The ambient light DL is
The distance measuring reflected light L2 is received by the light wave distance meter 15, and the light amount attenuator 7 is transmitted. That is, the light amount attenuator 7 attenuates the distance reflection light L2 by the same ratio.

The light transmitted through the light quantity attenuator 7, that is, the distance measurement reflected light L2 and the disturbance light DL, are transmitted by the bandpass filter 1
S / N separation by 4. That is, the distance measurement reflected light L2
And the ambient light DL is separated. Then, only the distance measurement reflected light L2 enters the light receiving element 6, and the ambient light DL does not enter. As a result, the adverse effect of the ambient light DL is reduced. However, in reality, the S / N separation cannot be completely performed, so that the adverse effect of the ambient light DL cannot be completely eliminated.

On the other hand, the distance measuring reflected light L2 is reflected by the light shielding plate 10.
When the light is blocked and the reference light LR is output, the ambient light DL is also blocked by the light blocking plate 10 and does not enter the light amount attenuator 7 and the light receiving element 6. Therefore, unlike the conventional optical distance meter, when the reference light LR is received, the S /
N does not decrease. Therefore, the distance can be measured more accurately as compared with the conventional lightwave distance meter.

As described above, in the present embodiment, the position of the light shielding plate 10 is arranged before the light amount attenuator 7 as viewed from the light receiving element 6. That is, it is arranged on the light receiving side and in front of the light quantity attenuator 7. Preferably, the position of the light shielding plate 10 is set at the position of the parallel light flux or near the condensing point. As described above, by disposing the light shield plate 10 at the position where the spread of the light flux is small, there is an advantage that the light shield plate 10 can be designed small. Distance measurement reflected light L2, reference light LR
It is disadvantageous in terms of the physical size of the light-shielding plate 10 when the light-shielding plate 10 is arranged in a place where the light flux has a spread.

This point is also taken into consideration in the illustrated example. That is, the reference light LR emitted from the first split prism 2 on the light emitting side is in the state of a parallel light flux after passing through the first relay lens 8 and before entering the second split prism 5 on the light receiving side. It is converted to the converging direction by the relay lens 9. The light shielding plate 10 is arranged at the position of the converged state.

As described above, the solar light S
The disturbance light is collected by the light shielding plate 10 when the distance measuring light L
Only when the optical path of 1 is selected, the reference light LR
When is selected, the light quantity attenuator 7
Can be protected from the ambient light DR, and deformation due to burning or heat can be prevented. Therefore, for example, when the switching ratio of the distance measuring light L1 and the reference light LR is 50% each, the heat resistance of the light quantity attenuator 7 is half that of the conventional one. That is, it is possible to use a light amount attenuator having a lower heat resistance than the conventional one, for example, a resin attenuator. Thereby, vibration resistance and cost performance can be improved.

The present invention is not limited to the above embodiment. The light shielding plate is not limited to the above-mentioned arrangement position, and may be arranged on the light receiving side and in front of the light amount attenuator, for example, on the optical path of the distance measurement reflected light before entering the light amount attenuator.

The present invention can also be applied to various other optical distance meters such as the conventional optical distance meter shown in FIG. In either case, the light shielding plate may be arranged on the light receiving side and in front of the light amount attenuator. Thereby, the same effect as that of the above-described embodiment can be obtained.

Further, the present invention may be applied to an optical distance meter using a reflecting prism without using the surface of the object to be measured. Thereby, for example, when disturbance light such as sunlight erroneously enters the optical distance meter, the light quantity attenuator can be protected by the light shielding plate.

[0086]

According to the present invention, the light shielding plate is provided on the light receiving side,
Moreover, since it is arranged in front of the light amount attenuator, when the distance measurement reflected light is blocked by the light shielding plate, ambient light is also blocked, so that the light amount attenuator does not enter.

Therefore, when receiving the reference light, the adverse effect of the ambient light does not occur. Therefore, the distance can be measured more accurately than the conventional lightwave rangefinder.

Moreover, it is possible to prevent the light attenuator from being burnt or deformed by heat when receiving the reference light. As a result, it is possible to use a light amount attenuator having a lower heat resistance than conventional ones, for example, a resin attenuator.

When a light attenuator made of resin is used, vibration resistance and cost can be improved as compared with the case of using a conventional glass attenuator.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a lightwave rangefinder according to a preferred embodiment of the present invention.

FIG. 2 is a schematic diagram showing a conventional optical distance meter.

FIG. 3 is a schematic diagram for explaining distance measurement using a reflection prism.

FIG. 4 is a schematic diagram for explaining distance measurement using a non-prism optical distance meter.

FIG. 5 is a schematic view showing another conventional optical distance meter.

[Explanation of symbols]

 1,31 Light emitting element 2 First split prism 3,33 Right angle mirror 4,34 Objective lens 5 Second split prism 6,36 Light receiving element 7,37 Light quantity attenuator 8 First relay lens 9 Second relay lens 10,11, 30 Light-shielding plate 12 Light emitting optical system 13 Light receiving optical system 23 Distance measuring object 14 Bandpass filter 15 Lightwave distance meter 20 Lightwave distance meter 21 Reflecting prism 23 Distance measuring object 35 Bandpass filter L1 Distance measuring light L2 Distance measuring reflected light L0 Luminous flux for distance measurement LR Reference light DR Diffuse reflection DL Ambient light S Sunlight

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasutaka Katayama 75-1 Hasunumacho, Itabashi-ku, Tokyo Topcon Co., Ltd. (72) Inventor Kazushige Koshikawa 75-1 Hasunuma-cho, Itabashi-ku, Tokyo To In Pucon (72) Inventor Takeshige Saito 75-1 Hasunuma-cho, Itabashi-ku, Tokyo Inside Topcon Co., Ltd.

Claims (2)

[Claims] 1. A light-wave range finder that includes a light amount attenuator for adjusting the amount of reflected distance measuring light received from an object for distance measurement, and a switchable light shield in a distance measuring device for obtaining a distance from the adjusted distance measuring reflected light and reference light. An optical distance meter, wherein a plate is arranged on the light receiving side and in front of the light quantity attenuator. 2. A light-wave rangefinder that is provided with a light amount attenuator for adjusting the amount of reflected distance measuring light received from an object for distance measurement, and is a switchable light shield in a distance measuring device for obtaining a distance from the adjusted distance measuring reflected light and reference light. A lightwave distance meter characterized in that a plate is arranged on the light receiving side and in front of a light quantity attenuator, and an optical path of distance measuring light and an optical path of reference light are alternately switched by a light shielding plate.