JP2000097700A - Surveying instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce light noise in an optical system by cutting off leaked light transmitted through the gap between optical members which need to be provided separately. SOLUTION: In the surveying instrument equipped with an optical system having a distance measuring means, an elastic flexible light shield member 22 which blocks the gap between optical members 10 and 20 arranged separately among the optical members constituting the optical system is provided in the gap. The light shielding member 22 cuts off the leaked light 19 transmitted through the gap between the optical members 10 and 20, so noise light in the optical members 10 and 20 is reduced to improve the measurement precision.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surveying device, and more particularly to a surveying device for measuring a distance by a light wave.

[0002]

2. Description of the Related Art FIG. 2 shows a main part of a surveying device. The surveying device is a leveling unit 1 attached to a tripod, like a general surveying device, a base unit 2 provided on the leveling unit 1, The base 2
And a telescopic unit 4 rotatably provided on the mounting unit 3 about a horizontal axis. Further, in the automatic surveying device, the support unit 3 and the telescope unit 4 are driven to rotate by a built-in motor (not shown), and can be operated remotely or automatically.

The telescope unit 4 has an optical system for irradiating measurement light and receiving reflection from a target object, and detects, collimates, and tracks the target object based on the received reflected light. It has a tracking means and a distance measuring means for measuring a distance to a target object.

The optical system has a dichroic prism, and the reflected light incident on the optical system from the object to be reflected is reflected by the dichroic prism to a visible light wavelength band, a tracking wavelength band, and a distance measurement. The measurement light beams in the divided wavelength bands for tracking and distance measurement are respectively guided to the tracking means and the distance measurement means to collimate the target object, to track or to reach the target object. A distance measurement is performed.

An example of the optical system will be described with reference to FIG.

On the optical axis O, an objective lens 5, a focusing lens 6,
An erect prism 7, a focusing mirror 8, and an eyepiece 9 are sequentially disposed, and an optical means, preferably a dichroic prism 10, is disposed between the objective lens 5 and the focusing lens 6.

The dichroic prism 10 has a first dichroic mirror surface 14 and a second dichroic mirror surface 15 on which wedge prisms 12 and 13 are adhered to opposite surfaces of a penta type prism 11.

The first dichroic mirror surface 14 transmits visible light and reflects infrared light out of the reflected laser beam incident thereon, and the second dichroic mirror surface 15 transmits distance measuring light. It reflects tracking light.
Distance measuring means (not shown) is provided on the reflection optical axis of the first dichroic mirror surface 14, and tracking means (not shown) is provided on the reflection optical axis of the second dichroic mirror surface 15.

The tracking light and the ranging light of the measuring light emitted from the telescope unit 4 are reflected by the target object, and when the reflected measuring light enters from the objective lens 5, the first dichroic mirror surface 14 detects the infrared light. The measuring light which is light, ie, the tracking reflected light and the distance measuring reflected light is reflected, and the visible light is transmitted. The transmitted visible light is imaged by the focusing mirror 6 by the focusing mirror 8, and the formed image is again imaged on the retina of the surveyor together with the scale of the focusing mirror 8, and collimation is performed.

[0010] Of the infrared light reflected by the first dichroic mirror surface 14, the tracking light is reflected on the second dichroic mirror surface 15, and the distance measuring light is transmitted. The tracking reflected light is emitted from the pentagonal prism 11 in a direction crossing the optical axis O, and is received by the tracking means. Based on the result received by the tracking means, the attitude of the surveying device is automatically adjusted so that the target object is located at the collimation center of the surveying instrument.

The distance measuring means will be described.

A split mirror 20 for receiving and emitting light is arranged to face the wedge-shaped prism 13. The cross-sectional shape of the light-receiving and splitting mirror 20 is a substantially isosceles triangle, and the apex of the triangle faces the dichroic prism 10, and two surfaces sandwiching the apex are reflection surfaces. A light emitting element 16 is provided facing one reflection surface, and a light receiving element 17 is provided facing the other reflection surface. In FIG. 4, reference numeral 18 denotes a reflection mirror provided on the target object.

A distance measuring light for distance measurement is emitted from the light emitting element 16, reflected by one reflection surface of the light receiving / emitting split mirror 20, and irradiating a target object from the telescope unit 4 through the dichroic prism 10. Is done. A laser beam of tracking light is also emitted from the telescope unit 4 at the same time. The measurement light is reflected by the reflection mirror 18 of the target object and enters the telescope unit 4. The incident measuring light is split into distance measuring light by the dichroic prism 10, and the distance measuring light is reflected by the other reflection surface of the light receiving / emitting split mirror 20 and enters the light receiving element 17. The distance to the reflection mirror 18 is measured based on the result received by the light receiving element 17.

An error in the frame (not shown) supporting the dichroic prism 10 and the light receiving / emitting split mirror 20 and mechanical and optical errors in the dichroic prism 10 and the light receiving / emitting split mirror 20 are inevitable. Therefore, FIG.
As shown in FIG. 6, the dichroic prism 10
In order to align the optical axis of the light receiving / emitting split mirror 20 with the light receiving / emitting split mirror 20, the position of the light receiving / emitting split mirror 20 must be adjusted with respect to the dichroic prism 10. Therefore, a gap G is provided between the dichroic prism 10 and the light receiving / emitting split mirror 20.
Is provided.

[0015]

As described above, since the gap G exists between the dichroic prism 10 and the light receiving / emitting split mirror 20, a part of the laser beam emitted from the light emitting element 16 (light leakage). The light 19 is reflected on the surface of the dichroic prism 10 and enters the light receiving element 17 through the light receiving / emitting split mirror 20. The light leaking 19 entering the light receiving element 17 is reflected by the light receiving / emitting split mirror 20.
It becomes noise light with respect to the reflected light for distance measurement reflected by. When the distance of the target object increases, the intensity of the distance measuring reflected light entering the light receiving element 17 decreases, so that the S / N ratio between the distance measuring reflected light and the noise light decreases, and the distance measurement is performed. There is a problem that accuracy and reliability of the device are affected.

In view of the above circumstances, the present invention is to reduce light noise in an optical system by blocking light leaking through a gap between optical members which need to be provided separately. A part of the laser beam from the light emitting element is reflected by the dichroic prism at the light receiving and emitting part, so that it does not directly enter the light receiving element, and the optical axis of the light receiving and emitting split mirror can be adjusted for the dichroic prism. It is assumed that.

[0017]

According to the present invention, there is provided a surveying apparatus having an optical system having a distance measuring means, wherein a plurality of optical members constituting the optical system are separated from each other. The present invention relates to a surveying device provided with an elastic and flexible light-blocking member for closing the gap in the gap, and a dichroic prism in which the optical member divides distance measuring light, and a light receiving and emitting light provided to face the dichroic prism. A light-emitting element that emits distance measurement light is provided on one side of the split mirror, and a light-receiving element that receives reflected light reflected from a target object and split by the dichroic prism is provided on the other side The light-shielding member is related to a surveying device provided between the light receiving / emitting split mirror and the dichroic prism, and the light-shielding member blocks light leaking through a gap between the optical members. It reduces the noise light inside the optical member, thereby improving the measurement accuracy.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a main part of the present embodiment.
In the figure, the same components as those shown in FIG. 4 are denoted by the same reference numerals.

A light-receiving / emitting split mirror 20 is disposed so as to face the entrance / exit surface 21 of the dichroic prism 10.
The light-receiving / emitting split mirror 20 is disposed so that the top is opposed to the entrance / exit surface 21, and a light-emitting element 16, for example, an LED is provided facing one of the two surfaces sandwiching the top, and the other is provided. A light receiving element 17 is provided to face the surface.

A light-shielding member 22 is sandwiched so that no gap is formed between the top of the light-receiving / emitting split mirror 20 and the entrance / exit surface 21. The light shielding member 22 is made of a material having high elasticity and flexibility, for example, rubber, foamed rubber (foamed polyurethane, foamed butyl rubber) and the like.

The light receiving / emitting split mirror 20 is fixed by aligning the optical axes of the light receiving / emitting split mirror 20 and the dichroic prism 10 (see FIGS. 5 and 6). The light blocking member 2
Reference numeral 2 has a sufficient amount of deformation so that a gap does not occur between the light receiving / emitting split mirror 20 and the dichroic prism 10 even when the position of the light receiving / emitting split mirror 20 is adjusted for optical axis alignment.

A laser beam for distance measurement is emitted from the light emitting element 16, reflected by the light receiving / emitting split mirror 20, and irradiating a target object through the dichroic prism 10. The measuring light reflected and incident on the target object is split into distance measuring light by the dichroic prism 10, and the distance measuring light is reflected by the light receiving / emitting split mirror 20 and enters the light receiving element 17. A light receiving signal is input from the light receiving element 17 to an arithmetic unit of a distance measuring unit (not shown), and a distance to a target object is measured based on a result of the received light.

Since the gap between the light-receiving and splitting mirror 20 and the dichroic prism 10 is completely closed by the light-shielding member 22, light leaking from the light-emitting element 16 does not directly enter the light-receiving element 17; The accuracy and reliability of the detection of the reflected light for distance measurement by the element 17 are improved, and the accuracy and reliability of the distance measurement are improved.

In the above embodiment, the light leakage between the dichroic prism 10 and the light-receiving and splitting mirror 20 has been described. However, it is needless to say that the light-shielding can be performed between two or more optical members provided separately. Nor.

[0026]

As described above, according to the present invention, reflection noise inside the optical system can be reduced.
The N ratio is improved, and an excellent effect of improving distance measurement accuracy and measurement reliability especially at a long distance is exhibited.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a main part of an embodiment of the present invention, and is a cross-sectional view corresponding to the line AA in FIG.

FIG. 2 is an external view of a surveying device.

FIG. 3 is a schematic configuration diagram showing an optical system of the surveying device.

FIG. 4 is an explanatory diagram of a light emitting / receiving section in the distance measuring means, and is a cross-sectional view taken along line AA of FIG. 3;

5 is an explanatory diagram of optical axis alignment between a dichroic prism and a light receiving / emitting split mirror in the light receiving / emitting unit, and is an enlarged view of a main part of FIG. 3;

6 is an explanatory diagram of optical axis alignment between a dichroic prism and a light receiving / emitting split mirror in the light emitting / receiving unit, and is an enlarged view of a main part of FIG. 3;

[Explanation of symbols]

 Reference Signs List 10 dichroic prism 16 light emitting element 17 light receiving element 19 light leakage 20 light receiving / emitting split mirror 21 input / output surface 22 light shielding member

Claims (2)

[Claims] In a surveying instrument having an optical system having a distance measuring means, a gap is closed in a gap between optical members which are separately arranged among optical members constituting the optical system. A surveying instrument provided with an elastic and flexible light shielding member. 2. The method according to claim 1, wherein the optical member is a dichroic prism for splitting distance measuring light, and a light receiving / emitting split mirror provided to face the dichroic prism. A light receiving element is provided for receiving reflected light reflected from the target object and divided by the dichroic prism, and the light blocking member is provided between the light receiving / emitting split mirror and the dichroic prism. The surveying device according to claim 1.