JPH09152483A - Light wave distance measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of a multi reflection light when a reflective sheet is used, by providing a light restriction means so that an unnecessary outside luminous flux does not reach a measuring reflecting member. SOLUTION: Only an infrared light entering an area P is reflected at a reflective sheet 10 among an infrared light from a light transmitter 5 which enters a DM face of a dichroic film of a dichroic prism 2, and an infrared light entering a light transmission area P is not guided to the sheet 10. The area P is formed of the film DM of a predetermined width (d) adjacent to a border line KL1 of transmission/reception optical paths. Therefore, the transmitted light reflected at the area P enters, through an objective lens 1, only a central reflecting body 10a of a plurality of minute reflecting bodies of the sheet 10 which extends in a vertical direction including an optical axis AX, along a lower area of the axis AX. Then, the light enters the lens 1 along an upper area of the axis AX. In other words, the transmitted light entering the reflecting body 10a is wholly guided to a photodetector 6. Accordingly, a distance can be highly accurately measured while the generation of a multi reflection light is restricted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightwave distance measuring device, and more particularly to a device for measuring the distance to a measuring point based on the phase of light that reciprocates in an optical path to the measuring point.

[0002]

2. Description of the Related Art FIG. 3 is a diagram schematically showing a configuration of a conventional lightwave distance measuring apparatus. In addition, FIG.
FIG. 3 is a view of the dichroic film DM of FIG. 3B as viewed along the normal direction of the film. FIG. 4 is an optical path diagram in the apparatus of FIG. Referring to FIGS. 3 and 4, the infrared light from the light emitter 5 is
After being reflected by the lower half region Ps of the dichroic film DM of the dichroic prism 2, the light enters the lower half of the objective lens 1. The infrared light that has become parallel light through the objective lens 1 reaches the corner cube 7 installed at the measurement point as the transmission lights L1 to L4 along the lower region of the optical axis AX of the objective lens 1.

The transmitted lights L1 to L4 are transmitted to the corner cube 7
The reflected light becomes reflected lights RL1 to RL4. Received light RL
1 to RL4 enter the upper half of the objective lens 1 along the upper region of the optical axis AX. The light received through the objective lens 1 is reflected by the upper half region Pj of the dichroic film DM and then focused on the light receiver 6. In this way, the distance to the measurement point is measured based on the phase of the light received by the light receiver 6.

FIG. 5 is an optical path diagram when a ref sheet 10 is installed at a measuring point in place of the corner cube 7 in the light wave distance measuring apparatus of FIG. As shown in FIG. 5, when the reflection sheet 10 including the minute reflectors arranged in a sheet shape is used as a reflecting mirror, the reception lights RL1 to RL3 with respect to the transmission lights L1 to L3 are along the lower side region of the optical axis AX. And enters the objective lens 1. Received light RL1 through the objective lens 1
~ RL3 is the lower half region Ps of the dichroic film DM
After being reflected by, the light returns to the light emitting device 5 again.

That is, the optical axis A of the transmitted lights L1 to L5 incident on the reflector sheet 10 along the lower region of the optical axis AX.
Received light RL for transmitted lights L4 and L5 close to X
Only 4 and RL5 enter the objective lens 1 along the upper region of the optical axis AX. Further, the scattered light SL6 generated on the reflecting surface of the reflex sheet 10 also enters the objective lens 1 along the upper region of the optical axis AX. Thus, the received lights RL4 and RL5 are transmitted to the upper half region P of the dichroic film DM.
After being reflected by j, it reaches the light receiver 6.

As described above, the ref sheet 10 is used as the measuring reflecting mirror installed at the measuring point in the optical distance measuring apparatus of FIG.
When using, the received lights RL1 to RL with respect to the transmitted lights L1 to L3 that are incident on the ref sheet 10 apart from the optical axis AX.
3 returns to the light emitter 5 again. The received lights RL1 to RL3 reflected by the surface of the light emitter 5 enter the ref sheet 10 again via the objective lens 1. In this way, multiple reflection light that reaches the light receiver 6 is generated by reciprocating the optical path between the objective lens 1 and the ref sheet 10 a plurality of times. The multiple reflection light is also generated by the reflection of the received light reaching the light receiver 6 on the surface of the light receiver 6.

The multiple-reflected light has a distance information that is a multiple of the distance information included in the phase of the regular received light that reaches the photodetector 6 after reciprocating once in the optical path between the objective lens 1 and the reflector sheet 10. It has a corresponding phase. When the light receiver 6 receives the multiple reflection light by superimposing it on the regular reception light, the phase of the output signal of the light receiver 6 changes and a distance measurement error occurs. Conventionally, the reflectance of the surface of the light emitter and the light receiver is reduced,
By tilting the surface of the light emitter or the light receiver with respect to the optical axis, or by arranging a neutral density filter on the front surface of the light emitter or the light receiver, the generation of multiple reflected light is suppressed and distance measurement error does not occur. I am trying.

[0008]

As described above, in the conventional optical distance measuring device, in order to suppress the generation of multiple reflected light,
There is a constraint that a light emitter or a light receiver having a low surface reflectance must be selected. Further, if the light emitting device and the light receiving device are installed at an inclination or a neutral density filter is arranged, the light emitting efficiency and the light receiving efficiency decrease. In particular, since the intensity of received light is originally low, the reduction in light receiving efficiency limits the measurable distance of the lightwave distance measuring device.

The present invention has been made in view of the above-mentioned problems, and even when a reflection sheet is used as a measuring reflecting mirror, the surface reflectance is not restricted and the luminous efficiency and the light receiving efficiency are not reduced. An object of the present invention is to provide an optical distance measuring device capable of suppressing the generation of multiple reflected light.

[0010]

In order to solve the above-mentioned problems, in the present invention, the effective area of the objective lens is divided into two first areas with respect to a predetermined surface including the optical axis of the objective lens. A light sending optical system for sending light passing through the objective lens to the measuring reflecting member along the other side, and the effective area of the objective lens is divided into two parts with respect to a predetermined surface including the optical axis of the objective lens. And a light receiving optical system for receiving the reflected light from the measuring reflection member via the objective lens along the second region of, and for collimating and observing the measuring reflection member via the objective lens. A collimation optical system and for guiding the reflected light from the measurement reflection member, which is arranged in the optical path between the objective lens and the collimation optical system, to the light receiving optical system and the collimation optical system, respectively. And a light wave distance measuring device equipped with In, in the first region, the inner light flux of the light-sending optical system that is adjacent to the second region and passes along a predetermined region that is at least adjacent to the optical axis of the objective lens reaches the measurement reflection member, Further, a light limiting unit is provided for limiting the light flux of the light-transmitting optical system so that an outer light flux of the light flux of the light-transmitting optical system other than a portion corresponding to the predetermined area does not reach the measurement reflection member. An optical wave distance measuring device is provided.

According to a preferred aspect of the present invention, the light splitting means is a light splitting device which is installed obliquely with respect to a predetermined surface including the optical axis of the objective lens and which amplitude-divides the reflected light from the measuring reflection member. A first light splitting portion formed in a position corresponding to the predetermined area in the first area, and a second light formed in a position corresponding to the second area. A light transmitting portion formed at a position corresponding to a region apart from the predetermined surface other than the predetermined region in the first region on the light splitting surface (or A light reflecting section), the light sending optical system sends the light flux reflected (or transmitted) by the first light splitting section to the measurement reflecting member, and the light receiving optical system uses the second light Receiving (or transmitting) the luminous flux from the measuring reflection member reflected by the dividing section, The collimation optical system is based on the reflected light from the measurement reflection member that transmits (or reflects) the first light splitting portion, the second light splitting portion, and the light transmitting portion (or light reflecting portion). Collimate.

Further, according to another preferable aspect of the present invention, the light splitting means is provided obliquely with respect to a predetermined surface including the optical axis of the objective lens and the infrared light from the measuring reflection member. A dichroic surface for separating visible light, the dichroic surface having a first wavelength separating portion formed at a position corresponding to the predetermined region in the first region and a position corresponding to the second region. And a second wavelength separating section formed on the dichroic surface, the light limiting section being formed at a position corresponding to an area apart from the predetermined surface other than the predetermined area in the first area on the dichroic surface. A light transmitting portion (or a light reflecting portion), wherein the light transmitting optical system transmits the infrared light reflected (or transmitted) by the first wavelength separating portion to the measurement reflecting member, The light receiving optical system reflects at the second wavelength separating unit. (Or transmitted) infrared light from the measuring reflection member, and the collimation optical system is configured such that the collimation optical system includes the first wavelength separation unit, the second wavelength separation unit, and the light transmission unit (or light reflection unit). Collation is performed based on the reflected light from the measurement reflection member that has transmitted (or reflected).

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the light wave distance measuring apparatus of the present invention, light is sent to the reflecting member for measurement along one region with respect to the optical axis of the objective lens, and along the other region with respect to the optical axis. The reflected light from the reflecting member via the objective lens is received. Then, a part of the transmitted light flux is limited so that the light reaches the reflecting member only along a predetermined region adjacent to the other region with respect to the optical axis. Specifically, for example, when the infrared light reflected by the dichroic film is sent to the reflecting member, the light transmitting portion is formed adjacent to the dichroic film. Then, a part of the transmitted light flux is allowed to escape through the light transmitting portion so that the light reaches the reflecting member only along a predetermined region adjacent to the other region with respect to the optical axis.

Thus, when the reflection sheet is used as the reflection member for measurement, the light transmitted from the light emitter through the dichroic film and the objective lens is incident only on the central reflector of the reflection sheet along one region with respect to the optical axis. To do.
The transmitted light is reflected by the central reflector of the reflex sheet to become received light, and reaches the light receiver along the other region with respect to the optical axis via the objective lens and the dichroic film. In other words, the transmitted light that has entered the reflector of the central portion of the ref sheet is guided to the light receiver without returning to the light emitter again. As a result, in the present invention, generation of multiple reflected light can be suppressed.

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram schematically showing the configuration of a lightwave distance measuring apparatus according to a first embodiment of the present invention. FIG. 1 (b)
[Fig. 1] is a view of the dichroic film DM of Fig. 1 (a) as seen along the normal line direction of the film. In the device of FIG. 1, the light emitter 5
Emits infrared light, for example, as transmission light whose intensity is modulated based on the modulation signal from the oscillator 8. The infrared light from the light emitter 5 passes through the surface 2a of the dichroic prism 2 and then the surfaces 2b and 2 of the dichroic prism 2.
Each of c is totally reflected and is incident on the film surface of the dichroic prism 2 on which the dichroic film DM is formed.

As shown in FIG. 1B, the film surface of the dichroic prism 2 on which the dichroic film DM is formed is composed of three regions Pj, Ps and Pt.
Regions Pj and Ps indicated by hatched portions in the drawing have a characteristic of reflecting infrared light and transmitting visible light. On the other hand, the area P
The dichroic film DM is not formed at t, which is a light transmission region that transmits both infrared light and visible light. The boundary line KL1 between the region Pj and the region Ps is
It is an imaginary line that is perpendicular to the paper surface including the optical axis AX of the objective lens 1 in FIG. In addition, the region Ps and the region Pt
The boundary line KL2 with the line is a line spaced from the boundary line KL1 between the region Pj and the region Ps by a predetermined distance d in FIG.

The transmitted light reflected by the region Ps of the dichroic film DM of the dichroic prism 2 exits the surface 2c of the dichroic prism 2 and then enters the objective lens 1. The transmitted light that has become parallel light through the objective lens 1 is incident on the ref sheet 10 installed at the measurement point along the lower region of the optical axis AX of the objective lens 1. in this way,
The light emitter 5, the dichroic prism 2, and the objective lens 1 constitute a light-transmitting optical system for transmitting parallel light along one region with respect to the optical axis AX of the objective lens 1 to the reflection sheet 10 which is a reflection member for measurement. doing.

The received light reflected by the reflector sheet 10 is incident on the objective lens 1 along the upper region of the optical axis AX. The light received through the objective lens 1 is reflected by the region Pj of the dichroic film DM, then passes through the surface 2b of the dichroic prism 2, and is condensed on the light receiver 6. As described above, the objective lens 1, the dichroic prism 2, and the photodetector 6 are light receiving optics for receiving the received light from the reflection sheet 10 that is the measurement reflection member along the other region with respect to the optical axis AX of the objective lens 1. It constitutes the system. The surface 2b of the dichroic prism 2 reflects the transmitted light from the photodetector 5, and the area P of the dichroic film DM.
It has a function of transmitting the received light reflected by j and separating the so-called transmitted / received light.

On the other hand, for example, the reflected light from the entire reflex sheet 10 with respect to the sun rays, after passing through the objective lens 1,
It enters the dichroic film surface of the dichroic prism 2. Then, the regions Pj and P of the dichroic film surface
The visible light transmitted through s and the light transmitted through the light transmission region Pt form an image of the reflection sheet 10 on the focusing screen 3. The image of the reflex sheet 10 formed on the focusing screen 3 is magnified and observed through the eyepiece lens 4. In this way, the objective lens 1, the dichroic prism 2, the focusing plate 3, and the eyepiece lens 4 constitute a collimating optical system for collimating the ref sheet 10 which is a measuring reflection member.

In the distance measuring operation, first, in a state where the ref sheet 10 is collimated through the collimating optical system, the transmitting light is transmitted through the light transmitting optical system and the received light is received through the light receiving optical system. To do. The output signal photoelectrically converted by the light receiver 6 of the light receiving optical system is input to the phase detection circuit 9. The phase detection circuit 9 performs phase comparison between the output signal from the light receiver 6 and the modulation signal from the oscillator 8. Since the phase of the output signal from the light receiver 6 is proportional to the round-trip distance to the measurement point, the distance to the measurement point can be obtained based on the phase comparison result.

In the first embodiment, of the infrared light from the light transmitter 5 incident on the dichroic film surface of the dichroic prism 2, only the infrared light incident on the region Ps is reflected toward the reflector sheet 10 and the light is reflected. The infrared light incident on the transmission region Pt is not guided to the ref sheet 10. As described above, the region Ps is formed of the dichroic film having the predetermined width d formed adjacent to the boundary line KL1 which is the boundary line between the light transmitting optical path and the light receiving optical path. Therefore, the transmission light reflected by the area Ps passes through the objective lens 1 and then the reflection sheet 1
Of the plurality of zero minute reflectors, only the central reflector 10a extending in the direction perpendicular to the paper including the optical axis AX is incident along the lower region of the optical axis AX.

The central reflector 1 is arranged along the lower region of the optical axis AX.
The transmitted light that has entered 0a enters the objective lens 1 along the upper region of the optical axis AX. In other words, the transmitted light that has entered the central reflector 10a along the lower region of the optical axis AX is guided to the light receiver 6 without returning to the light emitter 5. In this way, in the first embodiment, the generation of multiple reflected light can be suppressed, and highly accurate distance measurement is possible.

FIG. 2 is a diagram schematically showing the configuration of a lightwave distance measuring apparatus according to the second embodiment of the present invention. Note that FIG.
FIG. 2B is a view of the dichroic film DM of FIG. 2A viewed along the normal direction of the film. As described above, in the first embodiment, the collimation optical system performs collimation based on visible light that has passed through the dichroic film DM. However,
For example, in the case where distance measurement is performed at a point where sunlight does not reach sufficiently, such as in a tunnel, the apparatus of the first embodiment cannot form the image of the ref sheet 10 necessary for the collimation operation.
Therefore, in the second embodiment, instead of the collimation method by visual observation through the eyepiece lens 4 of the first embodiment, for example, CC
The collimation method using the image pickup system 11 composed of D is adopted.

That is, in the light wave distance measuring apparatus of the second embodiment, the image pickup system 11 is used as the collimating optical system, and the formation area of the dichroic film DM is changed accordingly. Is different from Therefore, in FIG. 2, illustration of the oscillator 8 and the phase detection circuit 9 is omitted, and elements having basically the same functions as those of the constituent elements of FIG. 1 are designated by the same reference numerals. Hereinafter, the second embodiment will be described focusing on the differences from the first embodiment.

In the device of FIG. 2, infrared light from the light emitter 5 is incident on the dichroic film surface of the dichroic prism 2. As shown in FIG. 2B, the film surface of the dichroic prism 2 on which the dichroic film DM is formed is composed of four regions Pj, Ps, Pt and Pt ′. A dichroic film DM having a characteristic of reflecting infrared light is formed in regions Pj and Ps indicated by hatched portions in the figure. On the other hand, the dichroic film DM is not formed in the regions Pt and Pt ′, which is a light transmission region that transmits infrared light.

The boundary line KL between the area Pj and the area Ps
In FIG. 2A, reference numeral 1 is a virtual line that includes the optical axis AX of the objective lens 1 and is perpendicular to the paper surface. Further, the boundary line KL2 between the region Ps and the region Pt and the boundary line KL3 between the region Pj and the region Pt ′ are respectively separated from the boundary line KL1 between the region Pj and the region Ps by a predetermined distance d in FIG. 2B. Is a line that separates.

The transmitted light reflected by the region Ps of the dichroic film DM of the dichroic prism 2 passes through the objective lens 1 and then enters the central reflector 10a along the lower region of the optical axis AX. The received light reflected by the central reflector 10a passes through the objective lens 1 along the upper region of the optical axis AX, is then reflected by the region Pj of the dichroic film DM, and is condensed on the light receiver 6.

In the structure of the first embodiment, the CCD 1
Even if 1 is adopted, 90% or more of infrared light emitted from the entire ref sheet 10 does not reach the CCD 11,
It is reflected by the dichroic film DM. As a result, the collimation of the reflector sheet 10, which is a reflecting member, and thus the distance measurement cannot be performed in a tunnel where sunlight does not reach sufficiently. In the second embodiment, the infrared light emitted from the entire reflex sheet 10 passes through the objective lens 1 and then enters the dichroic film surface of the dichroic prism 2. Then, the infrared light transmitted through the light transmitting regions Pt and Pt ′ on the surface of the dichroic film forms an image of the reflector sheet 10 on the light receiving surface of the image pickup system including the CCD 11.

As described above, also in the second embodiment, all of the transmitted light that has entered the central reflector 10a along the lower region of the optical axis AX does not return to the light emitter 5 and is received by the light receiver 6 as well.
It is led to. As a result, generation of multiple reflected light can be suppressed, and highly accurate distance measurement is possible. Further, in the second embodiment, since the image of the ref sheet 10 can be formed based on the infrared light from the entire ref sheet 10, it is possible to perform highly accurate collimation and thus highly accurate distance measurement even in the tunnel. .

In each of the above-mentioned embodiments, an example in which infrared light is used as the transmission light is shown. However, visible light may be used as the transmitted light, and a light splitting means such as a half prism may be used instead of the dichroic prism. Further, in each of the above-described embodiments, the light reflected by the dichroic film is guided to the reflector sheet and the light receiver.
However, the light transmitted through the dichroic film may be guided to the reflector sheet and the light receiver. in this case,
As a light restricting means for restricting a part of the transmitted light with respect to the ref sheet, it is necessary to provide a light reflecting portion in place of the light transmitting portion of each embodiment.

[0031]

As described above, in the present invention, when a reflection sheet is used as the measurement reflection member, the transmitted light from the light emitter is incident on the central reflector of the reflection sheet along one region with respect to the optical axis, The light receiver is reached along the other region with respect to the optical axis. That is, since the transmitted light that has entered the reflector of the central portion of the reflector sheet is guided to the light receiver without returning to the light emitter again, the generation of multiple reflected light can be suppressed and highly accurate distance measurement can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of a lightwave distance measuring apparatus according to a first embodiment of the present invention. FIG. 1 (b) is the same as FIG.
It is the figure which looked at the dichroic film DM of (a) along the normal line direction of a film.

FIG. 2 is a diagram schematically showing a configuration of a lightwave distance measuring device according to a second embodiment of the present invention. Note that FIG.
It is the figure which looked at the dichroic film DM of (a) along the normal line direction of a film.

FIG. 3 is a diagram schematically showing a configuration of a conventional lightwave distance measuring device. Note that FIG. 3B is a view of the dichroic film DM of FIG. 3A viewed along the normal line direction of the film.

4 is an optical path diagram in the apparatus of FIG.

5 is an optical path diagram when a ref sheet 10 is installed at a measurement point in place of the corner cube 7 in the optical distance measuring device of FIG.

[Explanation of symbols]

 1 Objective Lens 2 Dichroic Prism 3 Focus Plate 4 Eyepiece 5 Light Emitter 6 Light Receiver 7 Corner Cube 8 Oscillator 9 Phase Detection Circuit 10 Ref Sheet 10a Central Reflector DM Dichroic Film

Claims (7)

[Claims] 1. The light transmitted through the objective lens to a measuring reflection member along a first area on one side where the effective area of the objective lens is divided into two parts with respect to a predetermined surface including the optical axis of the objective lens. And a predetermined plane including the optical axis of the objective lens, the effective area of the objective lens is 2
A light receiving optical system for receiving reflected light from the measuring reflection member via the objective lens along the other divided second region, and collimating the measuring reflection member via the objective lens. A collimating optical system for observing, arranged in an optical path between the objective lens and the collimating optical system, and reflecting light from the measuring reflecting member with the light receiving optical system and the collimating optical system. And a light splitting device for guiding each of the light splitting means to guide the light beam to the second region in the first region and passing along a predetermined region at least adjacent to the optical axis of the objective lens. The inner light flux of the light transmission optical system reaches the measurement reflection member, and the outer light flux of the light flux of the light transmission optical system other than a portion corresponding to the predetermined region does not reach the measurement reflection member. Luminous flux of light transmission optical system An optical distance measuring device, characterized in that it is provided with a light limiting means for limiting. 2. The light splitting means has a light splitting surface which is obliquely provided with respect to a predetermined surface including the optical axis of the objective lens and which splits the reflected light from the measuring reflection member in amplitude. The split surface has a first light splitting portion formed at a position corresponding to the predetermined region in the first region, and a second light splitting portion formed at a position corresponding to the second region, The light restricting means is a light transmitting portion formed on the light dividing surface at a position corresponding to an area apart from the predetermined surface other than the predetermined area in the first area, and the light transmitting optical system is , The light flux reflected by the first light splitting portion is sent to the measurement reflecting member, and the light receiving optical system receives the light flux from the measurement reflecting member reflected by the second light splitting portion. The collimating optical system transmits the first light splitting portion, the second light splitting portion, and the light transmitting portion. Claim 1, wherein the collimating based on the reflected light from the measuring reflector member having
The lightwave distance measuring device described in. 3. The light splitting means has a light splitting surface which is obliquely provided with respect to a predetermined surface including the optical axis of the objective lens and which splits the reflected light from the measurement reflecting member in amplitude. The split surface has a first light splitting portion formed at a position corresponding to the predetermined region in the first region, and a second light splitting portion formed at a position corresponding to the second region, The light restricting means is a light reflecting portion formed at a position on the light dividing surface corresponding to a region apart from the predetermined surface other than the predetermined region in the first region, and the light transmitting optical system is A light flux transmitted through the first light splitting portion is sent to the measurement reflection member, and the light receiving optical system receives a light flux from the measurement reflection member transmitted through the second light splitting portion, The collimation optical system is reflected by the first light splitting portion, the second light splitting portion, and the reflection excess portion. Light wave distance measuring apparatus according to claim 1, wherein the collimating based on the reflected light from the measuring reflector member. 4. The light splitting means has a dichroic surface which is obliquely provided with respect to a predetermined surface including the optical axis of the objective lens and which separates infrared light and visible light from the measuring reflection member. The dichroic surface has a first wavelength separating section formed at a position corresponding to the predetermined area in the first area, and a second wavelength separating section formed at a position corresponding to the second area. Wherein the light restricting means is a light transmitting portion formed on the dichroic surface at a position corresponding to an area apart from the predetermined surface other than the predetermined area in the first area, The optical system sends the infrared light reflected by the first wavelength classification section to the measurement reflection member, and the light receiving optical system reflects the measurement reflection reflected by the second wavelength classification section. Receiving infrared light from a member, the collimation optical system, The optical wave measurement according to claim 1, wherein collimation is performed based on reflected light from the measurement reflection member that has passed through the first wavelength separation unit, the second wavelength separation unit, and the light transmission unit. Distance device. 5. The dichroic surface has a second light transmitting portion formed at a position corresponding to an area in the second area, which is distant from the predetermined surface, and the collimation optical system includes the second light transmitting portion. Collimating based on infrared light from the reflection member for measurement that has passed through the first wavelength separation unit, the second wavelength separation unit, the light transmission unit, and the second light transmission unit. The lightwave distance measuring device according to claim 4. 6. The light splitting means has a dichroic surface which is installed obliquely with respect to a predetermined surface including the optical axis of the objective lens and which separates infrared light and visible light from the measuring reflection member. The dichroic surface has a first wavelength separating section formed at a position corresponding to the predetermined area in the first area, and a second wavelength separating section formed at a position corresponding to the second area. The light limiting means is a light reflecting portion formed at a position corresponding to a region apart from the predetermined surface other than the predetermined region in the first region on the dichroic surface, The optical system sends infrared light that has passed through the first wavelength separation section to the measurement reflection member, and the light-receiving optical system transmits from the measurement reflection member that has passed through the second wavelength separation section. The infrared light of the first collimation optical system, The optical distance measurement according to claim 1, wherein collimation is performed based on the reflected light from the measurement reflection member reflected by the wavelength separation unit, the second wavelength separation unit, and the light reflection unit. apparatus. 7. The dichroic surface has a second light reflecting portion formed at a position corresponding to an area in the second area, which is distant from the predetermined surface, and the collimating optical system includes the second light reflecting portion. Collimating based on the infrared light from the measurement reflection member reflected by the first wavelength separation unit, the second wavelength separation unit, the light transmission unit, and the second light transmission unit. The optical distance measuring device according to claim 6.