JPH09229687A - Automatic inclination correcting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize an automatic inclination correcting apparatus by providing a container having an upper face of a reflective material and a lower face of a transparent material and containing a transparent liquid with a free liquid level and an optical member which parallels emitted light rays and composing the structure of the apparatus in which the light rays enter the container from the lower face and are reflected by the upper face and projected through the lower face of the container in the vertical direction. SOLUTION: Since a laser diode 1 is positioned at a position of the focal length (f) of a collimator lens 2, laser light L from the laser diode 1 is horizontally paralleled and enters a half-prism 3. The laser light L reflected upward by a semi-transmissive face 3a of the prism vertically enters a transparent container 4 from a lower side. The laser light L is transmitted through the lower face 4B and a silicone oil C, reflected by a mirror of the upper face 4A of the container, again transmitted through the silicone oil C, the container's lower face 4B, and the prism 3, and projected as reflected laser light L1 downward. In the case the whole body of the apparatus is installed horizontally, the laser light L, L1 is not refracted by the silicone oil C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic inclination correcting device incorporated mainly in a surveying instrument used for surveying work.

[0002]

2. Description of the Related Art A surveying instrument is required to be installed on a vertical line of a surveying point provided at a surveyed location. Therefore, the surveying instrument is provided with a device for confirming the installation position, for example, a device for projecting a laser beam downward from the surveying instrument, and the surveying instrument is installed so that the position of the projected laser beam and the surveying point coincide with each other. However, if the projection direction of the laser beam is constant with respect to the surveying instrument, an installation error occurs due to the installation orientation of the surveying instrument not being horizontal. Therefore, there is an automatic tilt correction device that projects a laser beam vertically downward regardless of the attitude of the surveying instrument. A conventional automatic inclination correction device has a structure as shown in FIG. 4, for example, disclosed in Japanese Patent Laid-Open No. 63-222214. In FIG. 4, a laser beam 66 </ b> A from a laser diode 66 provided on the upper portion of the main body 61 of the surveying instrument is emitted downward through a light projecting lens 65. 67 is the projection lens 65
The optical axis of Below the light projecting lens 65, a transparent container 63 in which silicone oils 64A and 64B are enclosed is provided. Flat portions 63A, 63B, 63C of the transparent container 63
Are parallel. On the other hand, the main body 61 has a leveling device 62 for leveling the main body 61 in the lower part thereof.

Next, the operation of automatic tilt correction of this apparatus will be described. When the main body 61 is horizontal, the laser light projected from the main body 61 is vertically downward. As shown in FIG. 3, when the main body 61 is inclined from the horizontal by an angle θ41, the optical axis 67
Also tilts at an angle of θ41 from the vertical. At this time, since the liquid surfaces of the silicone oils 64A and 64B enclosed in the transparent container 63 are kept horizontal, the silicone oils 64A and 64B are kept horizontal.
B has a wedge shape with a wedge angle θ31. The laser light 66A
Is refracted when passing through the wedge-shaped silicon oils 64A and 64B, and becomes a laser beam 66B having a deviation angle θ42 from the optical axis 67 and projected outside the main body 61.

Here, the silicone oil 64A, 64
Assuming that the refractive indices of B are n41 and n42, respectively, the wedge angle θ
The relationship between 41 and the deviation angle θ42 is θ42 = (n41 + n42-2) θ
41 (this is called a correction conditional expression, and if θ42 = θ41, the laser light is always projected vertically downward), the silicone oils 64A and 64B are n41 = n42.
= 42 if using silicone oil of 1.500 = θ41
Therefore, the conditional expression for correction is satisfied. As a result, the emission direction of the laser beam 66A is corrected and always emitted vertically downward.

[0005]

However, in the above-mentioned device, since the structure of the container of silicone oil is complicated,
There are drawbacks that the manufacturing cost is high, the tilt correction device cannot be made compact, and the surveying instrument becomes large. An object of the present invention is to provide an automatic tilt correction device that is easy to manufacture, inexpensive, and compact, and contributes to downsizing of a surveying instrument.

[0006]

According to the invention described in claim 1, at least the upper surface (4A, 14A, 34) of the reflecting member is provided.
A) and a lower surface (4B, 14B, 34B) of the transparent member, and a transparent liquid (C, C) having a free liquid surface therein.
1, C3) is housed in a container (4, 14, 34), and an optical member (2, 12, 32) for collimating light emitted from a light source (1, 11, 31) is provided. The parallel light incident from the lower surface of the optical member is reflected by the upper surface and is projected vertically downward from the lower surface of the container.

Light from a light source enters a container containing a transparent liquid having a free liquid surface from its lower surface, is refracted by the transparent liquid, is reflected by the upper surface of the container, and then enters the transparent liquid again. It is refracted and emitted (projected) from the lower surface of the container. Therefore, the light is refracted twice, and the projection direction of the light is an angle of 2 (n−1) θ (θ is an angle within the correction range in which the main body is inclined, n is a refractive index of the transparent liquid). In response to the change, it emits downward. Here, if a liquid having a refractive index n = 1.500 is used as the transparent liquid, the angle of inclination of the main body and the angle change of the projection direction of light become equal,
Even if the surveying instrument equipped with this device is tilted, the emission direction of the light is always vertically downward.

According to a second aspect of the present invention, in the apparatus according to the first aspect, two upper and lower surfaces (4A and 4A) of the container are provided.
B) and the like are parallel, and the parallel light from the optical member is incident on the lower surface of the container in the upward direction from the lower surface of the container, and the light reflected by the upper surface is projected vertically downward. An optical member (3, 13) was provided.

Since the incident light from the light source and the light emitted vertically downward are coaxial, a more compact automatic inclination correcting device can be obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram illustrating the principle of a first embodiment of the present invention. In FIG. 1, a visible light laser diode 1 emits a laser light L in a horizontal direction. 2
Is a collimator lens having a focal length f, which is arranged at a position separated from the visible light laser diode 1 by the focal length f and collimates the laser light L. The half prism 3 has a semi-transmissive surface 3a that is obliquely provided, and bends the laser light L from the collimator lens 2 upward. Above the half prism 3, a transparent container 4 having an upper surface 4A of a flat mirror and a transparent lower surface 4B, in which silicone oil C having a free liquid surface is sealed, is provided. The silicon oil in the transparent container 4 has a refractive index of n, and a space 5 in contact with the liquid level CS of the silicon oil C is formed in the transparent container 4.

Next, the operation of the apparatus shown in FIG. 1 will be described. Since the laser diode 1 is arranged at the position of the focal length f of the collimator lens 2, the laser light L from the laser diode 1 becomes horizontal parallel light and the half prism 3
Incident on. The laser light L reflected upward by the semi-transmissive surface 3 a of the half prism 3 enters the transparent container 4 vertically from the lower surface. The incident laser light L passes through the lower surface 4B of the transparent container and the silicon oil C, is reflected by the mirror surface of the upper surface 4A of the container, is again transmitted through the silicon oil C, the lower surface 4B of the container, and the half prism 3, and is reflected laser light L1. And is projected downward.

When the entire apparatus (the transparent container 4, the laser diode 1, the collimator lens 2, etc., including other embodiments having different reference numerals below) is placed horizontally, the laser light L and the reflected laser light L1 are Since it is not refracted by the silicone oil C, it is projected vertically downward. At this time,
The projection direction of the reflected laser light L1 based on the entire device is referred to as the device optical axis Z. (When the entire device is tilted, the optical axis Z of the device is also tilted by the same angle.) Now, assuming that the entire device is tilted from the horizontal by an angle θ1, the liquid level CS of the silicon oil C is kept horizontal, and therefore the silicon oil C has a wedge angle. Form a liquid prism with θ1. Then, the laser light L reflected upward by the half prism 3
Is refracted by the silicon oil C by an angle of θ2 = (n−1) θ1 and strikes the upper surface 4A while being inclined by an angle θ2 with respect to the optical axis Z of the apparatus. Since the upper surface 4A is a mirror surface, the laser light L is totally reflected, enters the silicon oil C again at an angle of θ2 with respect to the optical axis Z of the apparatus, and is further refracted by (n-1) θ1. Through this. Then, it is transmitted through the lower surface 4B and the half prism 3, and becomes reflected laser light L1 'having an angle of .theta.3 from the optical axis Z of the device and projected downward.

Here, θ3 = θ2 + (n-1) θ1 = 2
(N-1) θ1, so if n = 1.5, θ3 = θ
It becomes 1, and tilt correction is established. That is, laser light L1 '
Is projected vertically downward regardless of the value of the tilt angle θ1 of the entire apparatus. FIG. 2 is a side sectional view of a prism adapter device that incorporates the above device and generates a centripetal laser beam. In FIG. 2, below the main body 110 is a leveling unit 120 for leveling the prism adapter device. In the housing of the main body 110, a visible light laser diode 11 is fixed with its optical axis horizontal, and a collimator lens 12 is fixed at a position separated from the laser diode 11 by its focal length f2. Lower surface 1 of transparent container 14
The half prism 13 is adhesively fixed to 4B.
The inner surface (lower surface) of the upper surface 14A of the transparent container 14 is a mirror surface. Further, the liquid-proof cylinder 1 is provided on the upper surface 14A.
7 is glued. Silicon oil C2 having a free liquid level CS2 is enclosed in the transparent container 14.
A battery box 190 for accommodating a battery 180 for supplying power to the laser diode 11 is provided in the housing of the main body 110.
Is provided.

A circular bubble tube 200 for leveling the prism adapter device is fixed above the main body 110, and an adapter portion 1 for mounting a prism 240 in the central portion.
10A is protruding. A prism holder 230 in which a prism 240 is rotatably attached to a horizontal axis.
The mounting part 220 provided at the bottom of the adapter is the adapter part 110.
It is inserted in A and is fixed by a fixing knob 210 provided on the side surface of the adapter section 110A.

Next, the operation of automatic inclination correction will be described. The body 110 is leveled by the leveling unit 120 while looking at the circular bubble tube 200 within the tilt correction range (for example, ± 5 ′). As a result, the main body 110 is tilted by the angle θ21 within the tilt correction range. The laser light L2 from the laser diode 11 is converted into horizontal parallel light by the collimator lens 12 and enters the half prism 13.

The laser light L2 reflected upward by the semi-transmissive surface 13A of the half prism 13 enters the transparent container 14 from the bottom surface. The refractive index n2 = 1.4 in the transparent container 14.
Silicone oil C2 of 1 is enclosed, and further transparent container 14
A space 1 in contact with the liquid level CS2 of the silicone oil C2
5 are formed. Since the liquid level CS2 of the silicone oil C2 in the transparent container 14 is kept horizontal, the silicone oil C2 forms a liquid prism having a wedge angle θ21.

The laser beam L2 reflected upward by the half prism 13 is θ22 = (n2-1) θ21 = 0.41.
It is refracted by the silicone oil C2 by an angle of θ21 and hits the upper surface 14A of the container. The upper surface 14A is
Since it is a mirror surface, it is totally reflected, and is incident on the silicone oil C again at an angle of θ22 from the device optical axis Z2 which is the projection direction of the laser beam L2 when the main body 110 is placed horizontally. It is refracted by 0.41.theta.21 and transmitted therethrough, then transmitted through the lower surface 14B and the half prism 13, and from the optical axis Z2 of the apparatus 2 (n2-1) .theta.21 = 0.82.
The reflected laser light L2 ′ having an angle of θ21 is emitted vertically downward from the prism adapter device.

Considering the inclination correction accuracy, assuming that the maximum inclination angle θ21 of the correction range is 5 ′ and the height h from the lower surface 270 of the leveling table to the survey point surface 260 is 3 m at maximum, the correction error Δ Is Δ = hTan [(1-0.82) θ21 = 3000Tan (0.18 / 5 ') = 0.78 mm. That is, the error of the vertical point from the surveying point of the prism is within ± 1 mm, and it is corrected with accuracy that does not hinder construction surveying. Strictly speaking, the height h is the height from the surveying point surface 260 to the reflecting surface of the transparent container upper surface 14A, but the height from the lower surface 270 of the leveling table to the surveying point surface 260 is adopted. It is an industry practice.
This is because the height from the lower surface 270 of the leveling table to the reflecting surface of the upper surface 14A of the transparent container is different depending on various surveying instruments, and each surveying instrument is sufficiently higher than the height from the surveying point surface 260 to the lower surface 270 of the leveling platform. This is because it is small (about 80 mm) and there is no problem in ignoring the error amount caused by this.

As described above, the transparent liquid (here, silicone oil C2) is n = 1.5 depending on the required correction accuracy.
Those having a refractive index close to 00 can be used. FIG. 3 is a diagram illustrating the principle of the second embodiment of the present invention. In FIG. 4, in a transparent container 34 in which an upper surface 34A is inclined by an angle θm with respect to a lower surface 34B, a silicone oil C3 (refractive index = n
3) is enclosed. Below the transparent container 34, the visible light laser diode 31 is provided on the lower surface 34B of the transparent container 34.
Of the laser diode 31 and its focal length f.
A collimator lens 32 is arranged at a position separated by 3.

Next, the operation of the apparatus shown in FIG. 3 will be described. The laser diode 31 has a focal length f3 of the collimator lens 32.
Since it is located at the position
The laser light L3 from the collimated light becomes parallel light.
From the lower surface 34B. Lower surface 34B of transparent container 34
Laser light L3 passes through the lower surface 34B of the container and the silicone oil C3, the upper surface 3 of the container
4A is incident at an angle of .theta.0 with respect to the normal line N3, is reflected by the mirror surface of the upper surface 34A, and becomes reflected laser light L31. This direction is the device optical axis Z3. Where θ0 =
If 2 · θm, the projection direction of the reflected laser light L31 coincides with the normal line N3, and is vertically downward.

Now, assuming that the entire apparatus is tilted at an angle θ31 from the horizontal, the liquid level CS3 of the silicone oil C3 is kept horizontal, so that the silicone oil C3 forms a liquid prism having a wedge angle θ31. Then, the laser light L3 incident from the lower surface 34B of the transparent container 34 is changed by the silicone oil C3.
θ32 = (n3-1) θ31 is refracted and the upper surface of the container is inclined by an angle θ32 with respect to the optical axis Z3 (N3) of the device, which is the emitting direction of the reflected laser light L31 when the entire device is placed horizontally. It hits 34A. Since the upper surface 34A is a mirror surface, the laser light L3 is totally reflected, enters the silicon oil C3 again at an angle of θ32 with respect to the optical axis of the apparatus, and is further refracted by (n3-1) θ31. This is transparent. Then, the light passes through the lower surface 34B of the transparent container and becomes reflected laser light L31 ′ having an angle of θ33 from the optical axis of the device, and is emitted downward.

Here, θ33 = θ32 + (n3-1) θ31 =
Since 2 (n3-1) θ31, if n3 = 1.5, θ
33 = θ31, and tilt correction is established. That is, the reflected laser light L31 ′ is emitted vertically downward regardless of the value of the tilt angle θ31 of the entire device. In the present embodiment, for convenience of explanation, the time when the entire apparatus is placed horizontally is used as a reference, but the reference state does not have to be strictly horizontal, and the reflected laser light in a state having a certain inclination may be used. The angle θ0 may be adjusted so that the emission direction is the vertical direction. Further, as in the second embodiment, the silicone oil C3 has n3 = within the allowable error range.
It goes without saying that a material having a refractive index close to 1.5 can be used.

[0023]

According to the first aspect of the present invention, since the structure of the transparent container can be simplified, it is possible to provide a tilt correcting device which is easy to manufacture, low in cost and compact. As a result, the surveying instrument can be downsized. The invention of claim 2 provides a more compact tilt correction device because a part of the optical path is common.

[Brief description of drawings]

FIG. 1 is an explanatory view of the principle of a first embodiment of the present invention.

2 is a side sectional view of a prism adapter device incorporating the device of FIG.

FIG. 3 is an explanatory diagram of the principle of the second embodiment of the present invention.

FIG. 4 is a side sectional view of a laser projection surveying instrument equipped with a conventional automatic tilt correction device.

[Explanation of symbols]

Visible light laser diode (light source) 2, 12, 32 ... Collimator lens (optical member) 3, 13 ... Half prism ( Second optical member) 4, 14, 34 ... Transparent container 4A, 14A, 34A ... Upper surface (mirror surface) 4B, 14b, 34B ... Lower surface (transparent portion) 5, 15, 35.・ ・ ・ Space C, C2, C3 ・ ・ ・ ・ ・ Silicon oil (transparent liquid) Ln, Ln '・ ・ ・ Laser light (n is an integer) θn1 ・ ・ ・・ ・ ・ Inclination angle of the entire device θn3 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Angle of the projected laser beam from the optical axis of the device when the entire device is inclined by the angle θn1

Claims (2)

[Claims] 1. A container having at least an upper surface of a reflecting member and a lower surface of a transparent member, in which a transparent liquid having a free liquid surface is housed, and an optical for collimating light emitted from a light source. An automatic tilt correction device comprising: a member, which is configured to enter from a lower surface of the container, reflected by the upper surface, and projected vertically downward from the lower surface of the container. 2. The apparatus according to claim 1, wherein the upper and lower two surfaces of the container are parallel to each other, and the parallel light from the optical member is incident on the lower surface of the container in the upward direction from the lower surface of the container. In addition, the automatic tilt correction device is provided with a second optical member for projecting the light reflected on the upper surface vertically downward.