JP2003270347A - Electro-optical distance meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To omit a collimation telescope for reducing a size and a cost in a distance meter transmitting distance measurement light toward a measurement point and for facilitating collimation work even in installation at an optional height. <P>SOLUTION: This distance meter is provided with a light source 20 emitting red laser distance measurement light L, a reflection prism 30 reflecting the distance measurement light toward the measurement point along a collimation axis O, an objective lens 10 converging distance measurement light reflected in the measurement point to be returned, and a light receiving element 40 arranged in a focal point of the objective lens. The reflection prism is arranged in front of the objective lens on the collimation axis. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surveying instrument such as a light-wave range finder which sends a distance measuring light toward a measuring point, a total station (electronic distance measuring and measuring instrument), or the like.

[0002]

2. Description of the Related Art FIG. 2 shows an optical system in a conventional phase difference type optical distance meter. Lightwave rangefinder, collimation axis (optical axis)
On O, an objective lens 10, a focusing lens 12, an erecting prism 14 for erecting an image inverted by the objective lens, a focusing screen 16 on which a cross line indicating the collimation axis O is drawn, and an eyepiece lens 18 are provided. It is equipped with a collimating telescope T arranged. In addition, the light wave range finder, as described below, is a light-transmitting optics that sends distance-measuring light L toward a target installed at a measurement point in order to measure a distance to the target installed at the measurement point. The system and a light receiving optical system for receiving the distance measuring light L reflected from the target are provided.

The light transmitting optical system is a distance measuring light L of infrared laser light.
A laser light source 2 such as a laser diode which emits 1, a collimator lens 3 which converts the distance measuring light L1 emitted from the laser light source 2 into parallel rays, and the distance measuring light L1 is further directed to the collimation axis O. It is composed of a reflecting mirror 4 which reflects light, and a reflecting prism 5 which reflects the distance measuring light L1 toward the target along the collimation axis O. The reflecting prism 5 includes an objective lens 10
It is fixed to a protective glass 38 arranged in front of.

The light receiving optical system is disposed on the collimation axis O and the objective lens 10 which collects the distance measuring light L1 reflected by the target, and the distance measuring light L1 transmitted through the objective lens 10.
The dichroic prism 7 that reflects the light toward the light receiving element 6 and the light receiving element 6 that converts the received distance measuring light L1 into an electric signal. The dichroic prism 7 has a reflecting surface 70 formed by vacuum-depositing a dielectric material on a joint surface of two prisms. The reflecting surface 70 reflects infrared rays but transmits visible light. . In this way, since the reflecting surface 70 of the dichroic prism 7 reflects infrared rays, most of the infrared distance measuring light L1 is reflected by the reflecting surface 70, and the distance measuring light L1 which is laser light enters the eyes of the operator. Since the reflective surface 70 allows visible light to pass therethrough, the operator can surely collimate the target with the collimating telescope T.

The distance measuring light L1 emitted from the laser light source 2
Travels back and forth to the target, is incident on the light receiving element 6, and is converted into an electric signal. Here, the distance to the target can be measured from the phase difference between the electric signal converted by the light receiving element 6 and the reference electric signal supplied to the laser light source 2.

Further, the distance measuring light L1 emitted from the laser light source 2
Is also extracted as reference light 66 by the beam splitter 60 and is incident on the light receiving element 6 via the optical fiber 68. Whether the distance measuring light L1 is sent to the target or is taken out as the reference light 66 is switched by the switching shutters 62 and 64. Then, the measurement value is obtained by the measurement using the reference light 66 and the measurement using the distance measuring light L1 reflected by the target.

At the time of surveying, the worker uses the collimation telescope T
While looking at, the collimation telescope T is rotated in the horizontal direction and the altitude direction, and the target and the crosshairs drawn on the focusing screen 16 are aligned with each other, so that the target is aligned with the collimation axis O. is necessary. Therefore, the collimation telescope T
In order to make it easier to see the crosshairs in the dark,
There may be provided a crosshair illumination device including a reflecting mirror 9 that reflects the illumination light emitted from the light source 8 toward the focusing screen 16.

[0008]

By the way, in the surveying instrument such as the above-mentioned optical range finder, the collimating telescope T is indispensable because it is necessary to collimate the target installed at the survey point in surveying. It is something. However, this collimating telescope T has a problem that it has a considerable size, is heavy and expensive because it accurately measures the distance, and prevents the surveying instrument from becoming smaller and lighter and reducing the cost. . Further, at the time of surveying, the height of the surveying instrument must be set according to the height of the worker so that the operator can easily look into the collimation telescope T, and this surveying instrument is installed at an appropriate height. There is also a problem that the work is troublesome.

Therefore, the present invention has been made in view of the above problems, and in a surveying instrument such as an optical wave range finder which transmits distance measuring light toward a measuring point, the collimation telescope is not provided, and the size is reduced. It is an object to reduce the weight and cost, and to make collimation work easy even when installed at an arbitrary height.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 reflects a light source which emits distance measuring light and reflects the distance measuring light toward a measuring point along a collimation axis. A lightwave rangefinder comprising a reflector, an objective lens that collects the distance measuring light reflected and returned at the measuring point, and a light-receiving element installed at a focal position of the objective lens, The distance measuring light is a visible laser light, and the reflector is installed in front of the objective lens on the collimation axis.
As a result, the irradiation point of the distance measuring light, that is, the laser spot is viewed with the naked eye, and the direction of the optical rangefinder is adjusted so that the laser spot coincides with the measuring point. The collimation work that matched the intersection of the lines and the measurement point can be done without the collimation telescope.

According to a second aspect of the invention, in the first aspect of the invention, the distance measuring light is red laser light. This makes it easier to visually recognize the laser spot.

According to a third aspect of the present invention, a vertical axis that supports the optical distance meter according to the first or second aspect so as to be horizontally rotatable,
A surveying instrument having a horizontal axis that supports the lightwave rangefinder so as to be vertically rotatable, each rotation angle around the horizontal axis and the vertical axis of the lightwave rangefinder, and measuring the distance to the measurement point. It is characterized by displaying. As a result, this surveying instrument can perform collimation work without a collimation telescope, and can also measure azimuth, altitude, and distance.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A phase difference type optical distance meter which is a preferred embodiment of the present invention will be described in detail below.
FIG. 1 is a vertical cross-sectional view of this lightwave rangefinder.

As will be described later, this lightwave rangefinder measures the distance L to the target 50 installed at the measuring point in order to measure the distance to the target 50 installed at the measuring point.
And a light receiving optical system for receiving the distance measuring light L reflected from the target 50.

The light-transmitting optical system includes a laser light source 20 such as a laser diode which emits a distance measuring light L of red laser light which also serves as collimating light, and a collimator which makes the distance measuring light L emitted from the laser light source 20 parallel rays. The lens 22, the reflecting mirror 28 for reflecting the distance measuring light L in the collimation axis O (optical axis) direction, and the distance measuring light L reflected by the reflecting mirror 28 along the collimation axis O for the target 50.
The reflecting prism 30 or a reflector such as a reflecting mirror reflects the collimation axis O into a collimation axis for transmitting light and a collimation axis for receiving light. The reflecting prism 30 is fixed to a protective glass 38 arranged in front of the objective lens 10 on the collimation axis O for receiving light. A light quantity diaphragm 24 is also arranged in the light transmitting optical system. The light amount diaphragm 24 is configured to automatically adjust the light amount by a feedback circuit when the distance measuring light L passes through the disc by rotating the disc whose density varies along the circumferential direction. .

As the light receiving optical system, the objective lens 10 for converging the distance measuring light L reflected by the target 50 and the focal point of the objective lens 10 are installed to receive the condensed distance measuring light L. The light receiving element 40 which converts into an electric signal is provided.
The light receiving element 40 is fixed on a substrate 42 that processes an electric signal, and the method of measuring the distance from the received distance measuring light L is the same as that of the conventional phase difference type optical distance meter described above.

A beam splitter 60, switching shutters 62 and 64, and an optical fiber 68 are provided as an optical system for the reference light. Then, the switching shutter 62,
The distance measurement light L emitted from the laser light source 2 is switched by 64 to be transmitted to the target 50 or is guided as the reference light 66 to the light receiving element 40 via the optical fiber 68, and is reflected by the target 50. The measurement with the distance measuring light L and the measurement with the reference light 66 can be alternately performed.

The respective parts of the light transmitting optical system and the light receiving optical system described above are fixed in the housing 32. The bearing portion 36 of the housing 32 is supported by the horizontal shaft 34, and the housing 32 can rotate vertically around the horizontal shaft 34. The bearing portion 36 is arranged in the housing 32 and has a vertical cross section of a substantially "<" shape. A hole through which L passes is opened, and the front end of the housing 32 and the objective lens 10 are provided at the front end of the expanded side.
Are fixed and support the housing 32 as a cantilever. Since the bearing portion 36 is a cantilever, the collimation telescope T that has been conventionally required is no longer necessary. Therefore, the focusing lens 12, the erecting prism 14, and the focusing screen 16 that are components of the collimation telescope T are not necessary. This is because it is no longer necessary to extend the bearing portion 36 to the rear end portion of the housing 32 in order to support the eyepiece lens 18 and the like. Thus, the bearing 36
The cantilever makes it possible to reduce the size and weight of the lightwave rangefinder more than simply omitting the collimation telescope T.

Although not shown in the drawings, the pedestal, on which the pillar portion for supporting the horizontal shaft 34 is erected, is supported so as to be horizontally rotatable around the vertical axis, and the housing 32 can be rotated in any direction. Has become. Therefore, the distance from the optical distance meter to the measuring point is displayed on a display device (not shown) as the distance to the intersection of the horizontal axis 34 and the vertical axis. The distance between the light receiving element 40 and the intersection is calculated as a mechanical constant during distance measurement, and the distance to the target 50 is calculated.

Further, the light receiving element 40 is provided on the horizontal axis 34 that obstructs the path of the distance measuring light L condensed by the objective lens 10.
Is the vertex and the inside of the portion that intersects the side surface of the cone whose bottom is the objective lens 10 is hollowed out so that the distance measuring light L incident on the objective lens 10 is incident on the light receiving element 40 without waste.

When the distance is measured by this light wave distance meter, the laser light source 20 emits the distance measuring light L of red laser light, and the distance measuring light L is reflected by the reflecting mirror 28 and the reflecting prism 30 to measure the point. The light is transmitted toward the target 50 installed at. Here, the operator looks at the irradiation point of the distance measuring light L, that is, the laser spot 52 with the naked eye and sees the laser spot 52.
Adjust the orientation of the housing 32 so that is aligned with the center 54 of the target 50. Then, the laser spot 52
Is exactly aligned with the center 54 of the target 50,
I try to measure the distance. Of course, the distance can be measured even if the distance measuring light L is directly applied to the measuring point without installing the target 50 at the measuring point.

As described above, this optical rangefinder is different from the conventional one in that the laser light source 20 is changed to one that emits red light, and the collimation telescope T which is conventionally required is not provided. Eyepiece 18 of quasi-telescope T, focusing screen 1
6. The cross-shaped illumination device including the light source 8 and the reflecting mirror 9 and the dichroic prism 7 are not required, and no new parts are required, and the size and weight can be reduced and the cost can be reduced.

Further, since the light-sending optical system has the reflecting prism 30 installed in front of the objective lens 10 on the collimation axis O, the distance-measuring light L is sent to the target 50 without passing through the objective lens 10. Therefore, the distance measuring light L is not reflected by the objective lens 10 to the inside of the optical distance meter, and it is possible to prevent the measurement error due to the reflected light from occurring. In addition, the reflection prism 3
Since 0 is installed in front of the objective lens 10, the reflection prism 30 for the distance measuring light L is provided more than in the case where it is installed behind the objective lens 10 in which the distance measuring light L reflected by the target 50 is converged. The effect of shadows can be reduced, and this also prevents measurement errors from occurring.

By the way, the present invention is not limited to the above embodiment, but various modifications can be made. For example, the present invention is applicable to a total station, etc., in addition to the optical distance meter.
It is applicable to all surveying instruments that send distance measuring light to a measuring point. Further, as the distance measuring light L, red which is easy to visually recognize is used in the above-mentioned embodiment, but other colors may be used depending on the color of the wall surface near the measuring point. further,
Laser light source 20, collimator lens 22, light quantity diaphragm 24
It is also possible to dispose the reflection mirror 28 directly above the reflection prism 30 and omit the reflection mirror 28.

[0025]

According to the invention of claim 1, the following effects can be obtained. (1) Since the light source that emits the distance-measuring light of the visible laser light and the reflector that reflects the distance-measuring light toward the measuring point along the collimation axis are provided, By visually observing the laser spot and adjusting the direction of the optical distance meter so that the laser spot coincides with the measuring point, collimation work can be easily performed without the collimation telescope. (2) The collimation telescope, which was necessary in the past, is no longer necessary, and for distance measurement, an objective lens that collects the laser light that has been reflected back at the measurement point and the focal position of this objective lens. It is only necessary to install a light-receiving element in the device and change the conventional light source to one that emits visible laser light.No new parts are required, and it is possible to reduce the size and weight of the optical rangefinder and reduce the cost. Become. (3) There is no need to look into the collimation telescope during collimation work, and collimation work is easy even if the optical distance meter is installed at an arbitrary height, so the burden on the operator is small and efficient surveying is possible. Can be done.

According to the second aspect of the invention, since the distance measuring light is red laser light, the laser spot can be easily visually recognized and the collimation work can be further facilitated.

According to the surveying instrument of the third aspect of the present invention, the survey instrument has a vertical axis that supports the lightwave rangefinder in a horizontally rotatable manner and a horizontal axis that supports the lightwave rangefinder in a vertically rotatable manner. Each rotation angle of the meter about the horizontal axis and the vertical axis,
The distance to the measuring point is measured and displayed,
Alternatively, the same effect as that of the invention according to 2 is sent, and azimuth, altitude, and distance can be measured.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an optical distance meter that is an embodiment of the present invention.

FIG. 2 is a diagram showing an optical system of a conventional optical distance meter.

[Explanation of symbols]

10 Objective lens 20 Laser light source (light source) 30 Reflection prism (Reflector) 40 light receiving element L distance measuring light O collimation axis

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5J084 AA05 AB17 AC08 AD02 BA03                       BA20 BA51 BA56 BB04 BB11                       BB14 BB21 BB31 BB35 CA24                       DA01 EA21 EA31

Claims (3)

[Claims] 1. A light source that emits distance measuring light, a reflector that reflects the distance measuring light toward a measuring point along a collimation axis, and the distance measuring light that returns after being reflected at the measuring point. Is a light wave range finder having an objective lens for condensing light and a light receiving element installed at a focal position of the objective lens, wherein the distance measuring light is visible laser light, and the reflector is the visible light. An optical distance meter, which is installed in front of the objective lens on a quasi-axis. 2. The optical distance meter according to claim 1, wherein the distance measuring light is red laser light and also serves as a collimation axis. 3. A surveying instrument having a vertical axis for horizontally rotatably supporting the optical distance meter according to claim 1 and a horizontal axis for vertically rotatably supporting the optical distance meter,
A surveying instrument that measures and displays each rotation angle of the lightwave rangefinder around the horizontal axis and the vertical axis and the distance to the measurement point.