JPH08145676A - Laser projector for forming reference plane - Google Patents

Abstract

(57) [Abstract] [Purpose] For forming a reference plane that facilitates aiming point alignment and makes the detection sensitivity of the detector the same in any direction without complicating the optical system or increasing costs. To provide a laser projecting device. A laser beam optical path from a laser diode (23) to a pentaprism (35) in a reference plane forming laser projecting device (11) which forms a reference plane by reflecting laser light from a laser diode (23) on a pentaprism (35) and irradiating the laser beam with rotation. In addition, a laser beam cross-sectional shape conversion optical system 18 for converting a light beam having an elliptical cross section after being emitted from the laser diode 23 into a substantially circular cross section is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reference plane forming laser projecting apparatus for forming a reference plane by reflecting a laser beam from a laser light source with a reflecting means and irradiating the laser beam with rotation.

[0002]

2. Description of the Related Art In general, in the field of civil engineering and construction, a laser projecting device for forming a reference plane is formed by scanning a laser beam from a rotating light projecting portion toward an object to be surveyed around the device body to form a reference plane. (So-called laser planar),
By measuring the height of the laser spot that has reached the object to be surveyed, reference is made and height is measured.

Conventionally, a helium neon laser (He-Ne laser) is used as a light source in such a laser projector, but in recent years, as disclosed in Japanese Patent Laid-Open No. 2-179412,
A laser diode (L
Devices using D) have become known.

The laser projecting device using the laser diode as a light source can contribute to downsizing of the device and reduction of current consumption, but the cross section of the emitted light beam is reduced due to the flat emission end face of the laser diode. Because of the elliptical shape, and because the laser beam emitted from the laser diode has an astigmatic difference, the following problems occur. When a laser beam having an elliptical cross section is projected by rotation, the laser beam spot shows rotation at 0 to 360 °.
As in S _{0 to} S ₈ , the rotation around the optical axis makes it difficult to identify the center and it is difficult to recognize the horizontal reference. For example, when the position of the laser light flux having an elliptical cross section is detected by a separately provided detector having a pair of light receiving elements, the irradiation state of the light receiving element changes depending on the rotation position of the elliptical spot, and therefore the state of FIG. As in (a), (b), and (c), the output waveform of the detection signal is different, which may cause an error in the detection result. 20A shows an output waveform when the pair of upper and lower light receiving elements A and B shown in FIG. 19 receives the spots S ₂ and S ₆ at the rotational positions of 90 ° and 270 °, respectively, and FIG. (b) shows the light receiving elements A and B, which are 135 ° and 315
This is an output waveform when the spots S ₃ and S ₇ at the rotation position of ° are received. Further, FIG. 20 (c) shows output waveforms when the light receiving elements A and B receive the spots S ₄ and S ₈ at the rotational positions of 180 ° and 360 °. Due to the astigmatic difference of the emitted laser beam, it is difficult to narrow the beam diameter and it is extremely difficult to project the laser beam to a distant place.

In order to solve the above problems, the laser light beams emitted from the laser diode are rotated at an angle of rotation of 9 degrees.
There is known a laser surveying instrument that splits two kinds of laser light beams having an elliptical cross section different from each other by 0 ° and projecting them at the same time with their long axes aligned in a cross shape (see Japanese Patent Laid-Open No. 5-272967). .
However, according to such a conventional laser light projecting device, although the problem of can be alleviated to some extent, since a laser spot in which the major axis of the elliptical cross section is aligned in a cross shape is used for surveying, the aiming point alignment is performed. It is impossible to completely achieve the purpose of facilitating the above, or eliminating the unevenness of the detection sensitivity of the detector. Further, since the optical system for splitting into two kinds of laser light fluxes having different rotation angles by 90 ° is complicated, this leads to an increase in cost. Further, the above-mentioned conventional laser projecting device has not solved any of the above problems.

There is also known a method in which a collimator lens having a small NA (numerical aperture) is used to force vignetting on a laser beam having an elliptical cross section to obtain a laser beam having a circular cross section. However, according to this method, a large amount of light energy is wasted when vignetting the laser beam, so that a laser diode with a large output is required, resulting in an increase in current consumption and an increase in cost.

[0007]

SUMMARY OF THE INVENTION The present invention is based on the above-mentioned problems in the conventional laser projecting device, which facilitates aiming point alignment and which direction the detection sensitivity of the detector can be set without inviting a complicated optical system and an increase in cost. It is an object of the present invention to provide a laser light projecting device that can achieve the same in the above. A further object of the present invention is to provide a laser projecting device capable of solving the problem that the beam diameter cannot be narrowed due to the astigmatic difference of the emitted laser beam.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a laser projecting device for forming a reference plane, wherein a laser beam from a laser light source is reflected by a reflecting means and is radiated for rotation to form a reference plane. The laser light flux path from the light source to the reflecting means is provided with a laser light flux cross-sectional shape conversion optical system that converts a light flux having an elliptical cross-section after being emitted from the laser light source into a substantially circular cross-section. With this configuration,
It is possible to facilitate the aiming point alignment and to make the detection sensitivity of the detector the same in any direction without complicating the optical system and increasing the cost.

Further, a collimator lens for converting a laser light flux emitted from the laser light source into a parallel light flux is provided between the laser light source and the laser light flux cross-sectional shape conversion optical system,
The astigmatic difference contained in the laser beam is corrected by changing the distance between the laser light source and the collimator lens. This can solve the problem that the beam diameter cannot be narrowed due to the astigmatic difference of the emitted laser beam.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to illustrated embodiments. FIG. 1 is a sectional view showing the whole of a laser projecting device for forming a reference plane to which the present invention is applied. The laser light projecting device 11 has a substantially cylindrical housing 12 and a light projecting device main body 13 provided inside the housing 12. A cylindrical transparent member 16 surrounding the rotary light projecting portion 15 at the upper part of the light projecting device main body 13 is fixed to the upper part of the housing 12 in the figure, and a driving battery (not shown) for the laser light projecting device 11 is located below the housing 12. Battery case 1 for storing
7 is fixed.

The housing 12 has a sliding guide portion 19 having a substantially conical shape at the center of its upper portion and a circular hole 12a at the center of its lower portion. The circular hole 12a, in a state of being matched with the circular hole 17a formed in the central portion of the battery case 17,
A laser beam from above is emitted to the outside below the laser projecting device 11. Further, the slide guide portion 19 has a slide hole 19a in a substantially conical bottom portion. The inner diameter formed by the tip portion of the sliding hole 19a is set to be smaller than the outer diameter of the spherical portion of the bulging portion 21 described later.

The main body 13 of the projector is a hollow member 20 having a hollow portion extending in the vertical direction of FIG.
The rotary projection unit 15 is rotatably supported above the bearing 0 by means of a bearing 12. Hollow member 20
The bulging portion 21 of the rotary light projecting portion 15 (the light projecting device main body 13) is in a state where its spherical surface portion is brought into contact with the sliding hole 19a.
Is tilted in all directions around the rotation axis a, and the projected laser light flux L
It is supported so that the reference plane formed by ₃ can be freely adjusted with respect to the horizontal plane.

The hollow member 20 has laser light optical paths 20a and 20b which are orthogonal to each other inside thereof. The laser light optical path 20a is provided with a laser diode 23 that emits a visible laser light flux, a collimator lens 24, and a laser light flux cross-sectional shape conversion optical system 18 including a pair of anamorphic prisms 25 and 26 (see FIG. 12). .
The laser light optical path 20 b located on the extension of the rotation axis a of the rotary light projecting unit 15 has a light projecting optical system 22.

The laser beam cross-sectional shape conversion optical system 18 has a prism P which will be described later. As shown in FIG. 2, the light projecting optical system 22 has a polarization beam splitter 27 that receives a laser beam emitted from the prism P. The polarization beam splitter 27 has a polarization splitting surface (polarization splitting surface) 27a, and a ¼λ plate 28 is attached to the upper portion thereof. The 1/4 λ plate 28 is attached so that the axis direction of the 1/4 λ plate 28 is oriented at 45 ° with respect to the polarization direction of the incident light. Furthermore, on the upper surface of the 1/4 λ plate 28, a laser beam is transmitted toward the pentaprism 35 at a predetermined ratio, and the remaining laser beam is reflected toward the polarization splitting surface 27a of the polarization beam splitter 27. It has a semipermeable membrane 28a having a rate of about 10 to 20%. Here, after the 1/4 λ plate 28 provided between the polarization beam splitter 27 and the semi-transmissive film 28a is reflected by the polarization beam splitter 27, most of the light is circularly polarized by the semi-transmissive film 28a. The light is transmitted as it is toward the pentaprism 35. The rest of the light is reflected by the semi-permeable film 28a, and further 1/4.
By passing through the λ plate 28 again, linearly polarized light in the direction opposite to that at the time of incidence is obtained. Therefore, the polarization beam splitter 2
The light directed to the polarization splitting surface 27a of No. 7 is not reflected by the polarization splitting surface 27a, that is, does not return to the laser diode 23 which is the laser light source, and the polarization splitting surface 27a.
Through all.

Below the polarization beam splitter 27 in FIGS. 1 and 2, wedge prisms 29a and 29b are provided. Above the polarization beam splitter 27 in the figure, the sliding cylindrical member 30 is fixed to the sliding cylindrical member 30.
At the same time, a focusing lens 31 movable in the optical axis direction and an objective lens 32 fixed in the laser light optical path 20b are provided.

The rotary light projecting unit 15 has a laser beam optical path 15a which is aligned with the laser beam optical path 20b and is continuous with the laser beam optical path 20b, and a pentagon having a diameter larger than that of the laser beam optical path 15a which is continuous with the laser beam optical path 15a. It has a prism housing portion 15b. A light projecting window 33 is formed on the side wall of the pentaprism housing portion 15b for projecting the laser light flux reflected and deflected by the pentaprism 35 housed inward to the outside of the device. The upper portion of the pentaprism housing portion 15b is opened, and the optical axis of the laser light optical path 15a is fitted into the circular hole 16a at the center of the upper portion of the transparent member 16.
It is aligned with the center of 6.

The pentaprism 35 is provided in the main body 13 of the light projecting device.
Is fixed to the rotary light projecting unit 15 so as to rotate integrally with the rotary light projecting unit 15, and constitutes a reflecting means for reflecting the laser beam on the rotation axis a of the rotary light projecting unit 15. .
As shown in FIG. 2, the penta prism 35 includes a light incident surface 35c on which a laser beam is incident and a light incident surface 35c.
Is set to a predetermined angle with respect to the required reflectance (70 to 8
0%) of the semi-transmissive film 14 is provided on the first reflecting surface 35a on which the laser beam incident from the light incident surface 35c is incident.
And the angle θ formed by the first reflecting surface 35a that reflects the laser light flux reflected by the first reflecting surface 35a is 45.
The second reflecting surface 35b having
It has a light incident surface 35c from which the laser beam reflected by b is emitted and a light emitting surface 35d which makes 90 ° with the light incident surface 35c. On the second reflecting surface 35b, a reflection enhancing film is formed by aluminum vapor deposition or the like. Further, on the first reflecting surface 35a,
A wedge-shaped prism 34 is attached with the semipermeable membrane 14 interposed therebetween. The wedge-shaped prism 34 has the hypotenuse of the first reflecting surface 3
2 is arranged so that the exit surface 34a located in the upper part of FIG. 2 is parallel to the light incident surface 35c of the pentaprism 35.

On the other hand, the hollow member 20 includes a drive arm 37 extending rightward in FIG. 1 and a drive arm 39 orthogonal to the drive arm 37 in the depth direction of the drawing (see FIG. 3).
And have integrally. These drive arms 37,
39 is formed by inclining downward from the uppermost portion of the bulging portion 21, and has rollers 40 and 41 attached to the respective tip portions so as to match the spherical center of the bulging portion 21.

The housing 12 has, on its inner wall, a bracket 42 projecting toward the inner circumference of the housing 12. The bracket 42 has a gear support hole 42a.
Are formed. Also, the upper wall 12b of the housing 12
A gear support hole 43 is formed at a position facing the gear support hole 42a in FIG. These gear support holes 42
Shafts at both ends of the adjusting screw 45 are rotatably fitted in the a and 43. A first level adjusting motor 44 is also fixed to the bracket 42. This first
Pinion 4 fixed to the rotary shaft of level adjustment motor 44
9 is meshed with the transmission gear 50 fixed to the lower end of the adjusting screw 45. An adjusting nut 46, which constitutes a feed screw mechanism together with the adjusting screw 45, is screwed onto the adjusting screw 45. An operating pin 47 protruding outward is fixed to the outer periphery of the adjusting nut 46, and the operating pin 47 is in contact with the roller 40 from above. The adjustment nut 46 is also restricted from rotating relative to the housing 12 by a support mechanism (not shown).

As shown in FIG. 3, the housing 12 has a bracket 78 formed on the inner wall thereof so as to project toward the inner circumference of the housing 12. This bracket 78
Has a gear support hole (not shown) formed therein, and a gear support hole (not shown) is formed at a position on the upper wall of the housing 12 facing the gear support hole. The shaft portions at both ends of the adjusting screw 79 are rotatably fitted in the both gear supporting holes. The bracket 78 has a second
The level adjusting motor 75 is fixed. The pinion 76 fixed to the rotating shaft of the second level adjusting motor 75.
Engages with a transmission gear 77 fixed to the lower end of the adjusting screw 79. An adjusting nut 80, which constitutes a feed screw mechanism together with the adjusting screw 79, is screwed onto the adjusting screw 79. An operating pin 81 protruding outward is fixed to the outer periphery of the adjusting nut 80, and the operating pin 81 is in contact with the roller 41 from above. The adjustment nut 80 is also restricted from rotating relative to the housing 12 by a support mechanism (not shown).

The housing 12 has, on its inner wall, a support projection 51 provided in a direction that bisects the angle formed by the drive arms 37 and 39 orthogonal to each other. A tension spring 52 is stretched between the support protrusion 51 and the hollow member 20. The hollow member 20 has the tension spring 52.
Thus, the rollers 40 and 41 biased upward by the same force are elastically contacted with the operation pins 47 and 81 from below. That is, the hollow member 20 is
Since the bulging portion 21 is urged toward the supporting protrusion 51 while being supported by the sliding hole 19a, the first and second level adjustments are performed in which the bulging portion 21 is rotationally driven based on a signal from a microcomputer (hereinafter referred to as a microcomputer) 82. The rotational position in the horizontal direction can be adjusted by the operation pins 47 and 81 that are moved up and down by the motors 44 and 75 for use. The hollow member 20
Has a bracket 70, 71 projecting in the opposite direction to the arms 37, 39 at the lower part thereof. Level detection sensors 72 and 73 are attached to the brackets 70 and 71, respectively.
The detection signal from 2, 73 is sent to the microcomputer 82.

A bracket 53 is provided at the bottom of the hollow member 20 so as to project outward. A bracket 55 facing the bracket 53 is formed on the upper portion of the bracket 53. These brackets 53 and 55 have gear support holes 53 facing each other.
a and 55a are formed. Both gear support holes 53a, 5
Shafts at both ends of the focusing screw 56 are rotatably fitted to the shaft 5a. A focusing motor 59 is fixed to the bracket 53. The pinion 60 fixed to the rotating shaft of the focusing motor 59 meshes with the transmission gear 61 fixed to the lower end of the focusing screw 56. A focusing nut 57, which constitutes a feed screw mechanism together with the focusing screw 56, is screwed onto the focusing screw 56. In the wall portion of the hollow member 20 corresponding to the sliding member 30,
An insertion window 63 is formed. One end of the focusing nut 57 inserted through the insertion window 63 is attached to the sliding member 30.
The other end of the transmission link 62 fixed to the lower end of the is fixed. Therefore, by driving the focusing motor 59 based on the signal from the microcomputer 82, the focusing nut 5 is passed through the pinion 60, the transmission gear 61, and the focusing screw 56.
7 is moved up and down, the focusing lens 31 is moved up and down via the link 62 and the sliding member 30, the focal length is adjusted, and the laser light beam projected from the rotary light projecting unit 15 is appropriately focused. You can

A bracket 65 is provided at the top of the hollow member 20 so as to project outward. A rotation motor 66 is fixed to the bracket 65, and a pinion 67 attached to a rotation shaft of the motor 66.
Engages with a transmission gear 69 fixed to the outer periphery of the rotary light projecting portion 15. Therefore, by rotating the rotation motor 66 based on the signal from the microcomputer 82, the rotary light projecting unit 15 can be rotated relative to the hollow member 20 via the pinion 67 and the transmission gear 69.

A rotation detecting sensor 83 is provided on the uppermost side of the hollow member 20 opposite to the bracket 65, facing upward. The rotation detection sensor 83 emits a light beam toward the upper side, that is, toward the transmission gear 69, and the transmission gear 69
After receiving the light flux reflected by a predetermined pattern (not shown) provided on the back surface of the device, it is sent to the microcomputer 82 as a signal. The microcomputer 82 calculates the rotation angle of the rotary light projecting unit 15 based on the received light receiving signal.

In FIG. 1, the prism P included in the laser beam cross-sectional shape conversion optical system 18 is schematically shown. The prism P, which is a feature of the present invention, will be specifically described below.

First, a first embodiment according to the present invention will be described with reference to FIG. In this embodiment, as the prism P, one anamorphic prism 25 having an apex angle α and a refractive index n is used. The collimating lens 24 located between the anamorphic prism 25 and the laser diode 23 has a sufficiently large numerical aperture (NA) and is arranged so as to have a predetermined incident angle i with respect to the anamorphic prism 25.

In the first embodiment having such a structure,
The laser beam emitted from the laser diode 23 and having an elliptical cross section is elliptical in cross section having a minor axis (minor axis) Di and a major axis (major axis) D ₀ (luminous flux diameter in a direction perpendicular to the paper surface) by the collimator lens 24. Is converted into parallel light. The laser light flux (FIG. 5) at the time of incidence of such a cross-sectional shape has its minor axis Di extended when it is incident on the anamorphic prism 25 at the incidence angle i, and the diameter on the minor axis Di side is the major axis D _0. The diameter is the same as the side diameter, and the light is ejected perpendicularly to the ejection surface 25a. Therefore, the emitted laser light flux at this time becomes a circular light flux having a diameter on the long axis D ₀ , as shown in FIG.

At this time, the short axis D of the cross section of the emitted laser light beam
Between i, the long axis D ₀ , and the apex angle α of the anamorphic prism 25, D ₀ / Di = cosα / cosi = cosα / (1−n ² · sin ²
The relationship α) ^1/2 = m holds (where m is the anamorphic magnification). That is, when the laser light flux emitted from the anamorphic prism 25 is to be a circular light flux whose diameter is the major axis D ₀ as described above, the apex angle α, the refractive index n, and the incident angle i are appropriately determined. Therefore, the required anamorphic magnification m
(D ₀ / Di) can be obtained.

The respective quantities of the anamorphic prism 25 are shown in FIGS. 7 and 8. FIG. 7 shows the anamorphic magnification m and the apex angle α.
FIG. 8 is a graph showing the correlation between the incident angle i with respect to the apex angle α and the surface reflectance Rp when the anamorphic magnification m is used as a parameter.

In FIG. 7, the refractive index n is 1.5,
Anamorphic prisms of 1.65 and 1.8 are used. In the figure, it can be seen that the required anamorphic magnification m can be obtained with a smaller apex angle α as the anamorphic prism having a larger refractive index n. Incidentally, in the case of an anamorphic prism with a refractive index n of 1.8, when the apex angle α is 30.5 °,
The anamorphic magnification m is 2.11. In FIG. 8, anamorphic prisms having anamorphic magnifications m of 2, 2.5 and 3 are used. In the figure, the larger the required anamorphic magnification m for the same apex angle α, the larger the incident angle i is required. Also, the larger the anamorphic magnification m, the smaller the vertical angle α.
Thus, the surface reflectance Rp becomes small.

In general, the laser beam emitted from the laser diode includes an astigmatic difference. However, if the astigmatic difference is left as it is, the diameter of the emitted laser beam cannot be narrowed down and the laser beam is distant. It becomes difficult to project light. In the first embodiment, the astigmatic difference contained in the laser light flux emitted from the laser diode 23 is corrected by changing the distance between the laser diode 23 and the collimator lens 24.

That is, assuming that the laser light flux does not include astigmatic difference at all, the wavefront of the light emitted from the collimator lens 24 is as shown in the figure when the distance between the collimator lens 24 and the laser diode 23 deviates from a predetermined position. 1
As shown in FIG. 1, it becomes a curved wavefront with defocus (it becomes a planar wavefront when the interval is a predetermined position). Since the cross section of the laser light flux emitted from the laser diode 23 is originally elliptical, the diameters thereof in the directions orthogonal to each other are different. That is, when the minor axis of this laser beam is ρ and the major axis is ρ ₀ , the amount of deviation from the reference plane S that appears on the curved wavefront on the minor axis ρ side is Wy,
The amount of deviation from the reference plane S that appears on the curved wavefront on the major axis ρ ₀ side is Wz. Here, when the light flux emitted from the collimator lens 24 passes through the anamorphic prism 25,
The short diameter [rho of the light beam is stretched in [rho _0, a circular light flux to radius [rho _0. However, since the amount of deviation in the minor axis direction is still Wy, it is Wy in the minor axis direction and Wz (for the same ρ ₀ ) in the major axis direction, resulting in a wavefront having an astigmatic difference (FIGS. 9 to 11). reference).

By the way, by moving the laser diode 23 relative to the collimator lens 24 by Δz or the like, depending on which direction the distance between the two is displaced from the reference distance (that is, whether to increase or decrease). The sign of the generated astigmatic difference can be changed. That is, by adjusting the direction and amount of the shift, it is possible to generate an astigmatic difference that cancels the astigmatic difference originally possessed by the laser light flux. The first embodiment focuses on the relationship between the laser diode 23 and the collimator lens 24 as described above, and by changing the distance between the two, the semiconductors as described with reference to the amounts Wy and Wz of the curved wavefronts described above. The astigmatic difference that cancels out the astigmatic difference originally possessed by the laser beam is positively formed and corrected. Therefore, it is possible to obtain a laser beam having no astigmatic difference that effectively uses the light energy. At this time, a defocus component remains on the wavefront, but this can be canceled by moving the focusing lens 31 with respect to the objective lens 32. As a result, it becomes possible to project the laser light beam to a long distance without any problem. In the second embodiment (FIG. 12), the third embodiment (FIG. 14), and the fourth embodiment (FIG. 15) which will be described later, the distance between the laser diode 23 and the collimator lens 24 is changed. The same effects as those of the first embodiment can be obtained.

The above description can be defined by the following equation. Wz = [{1- (1-NA ₀ ² ) ^1/2 } × ΔZ] ≈ ^1/2 × NA ₀ ² × ΔZ Wy = Wz × (ρ / ρ ₀ ) ² = Wz × 1 / m ² Therefore, def = (Wz + Wz / m ² ) / 2 = Wz / 2 × (1 + 1 / m ² ) As = Wz−Wz / m ² = Wz (1-1 / m ² ), where As: astigmatic difference, def: de Focus, NA: numerical aperture, m: anamorphic magnification (m = ρ ₀ / ρ), Wy: amount of deviation from the reference plane S at ρ on the minor axis side of the curved wavefront, Wz: at ρ ₀ on the major axis side of the curved wavefront Amount of deviation from the reference plane S, λ: wavelength of laser beam.

The present laser projecting device 11 having the above structure
Operates as follows. First, as shown in FIG. 1, the laser projecting device 11 is arranged at a desired position. In this state, when a main switch (not shown) is turned on, the laser diode 23 starts oscillating based on a signal from the microcomputer 82 and irradiates a laser beam. This laser light flux is converted into an elliptical parallel light flux by the collimator lens 24 and then incident on the anamorphic prism 25, and its minor axis diameter Di (see FIG. 5) is extended by the anamorphic prism 25, as shown in FIG. Such a light beam is converted into a circular light beam having a diameter D ₀ . Furthermore, this circular luminous flux
The light beam L directed upward by the polarization beam splitter 27
It is split into ₁ and a light beam L ₂ directed downward.

At this time, in FIG. 2, the laser beam L ₀ incident on the polarization beam splitter 27 is oscillated in a direction perpendicular to the plane of incidence including the normal line n of the polarization splitting surface 27a and the laser beam L _0. With S polarization component and P
In the case of linearly polarized light having no polarization component, this laser light beam L ₀ is totally reflected by the polarization splitting surface 27a and is deflected by 90 °, and goes upward in the figure. At this time, the 1/4 λ plate 28
Is attached to the polarization beam splitter 27 so that its axis direction is 45 ° with respect to the vibration direction of the incident light, so that the laser light flux L ₀ passes through the ¼λ plate 28,
The circularly polarized laser beam L ₁ is directed to the pentaprism 35. Further, the light is reflected by the semi-transparent film 28a and the polarization splitting surface 27a
The laser light flux L ₁ returned to ( ₁₎ is converted into linearly polarized light having a vibration direction orthogonal to that at the time of incidence by passing through the 1/4 λ plate 28 again. That is, the linearly polarized light of the S polarization component is converted into the linearly polarized light of the P polarization component. Therefore, the laser light flux which is the linearly polarized light of the P-polarized component passes through the surface 27a as the laser light flux L ₂ without being reflected by the polarization splitting surface 27a and goes downward in the figure, and further passes through the wedge prisms 29a and 29b. After passing through, it is emitted to the outside of the lower part of the laser projecting device 11.

On the other hand, the laser beam L ₁ directed upwards
Passes through the focusing lens 31 and the objective lens 32, and after passing through the light incident surface 35c of the pentaprism 35, the first and second
Are sequentially reflected by the reflecting surfaces 35a and 35b, and are deflected by 90 ° in the path, and are emitted from the light emitting surface 35d as a laser beam L _{3 in} a direction perpendicular to the laser beam L ₂ , that is, in the horizontal direction. The first reflection surface 3 of the laser beam L ₁
Except for the light reflected at a predetermined ratio by 5a, the light passes through a half mirror surface formed by a wedge prism 34 attached to the upper surface of the first reflection surface 35a of the penta prism 35, and is emitted upward. To be done. In this way, the laser light flux L ₀ emitted from the laser diode 23 is the laser light fluxes L ₁ , L ₄ , L ₂ , respectively projected in the vertical direction of FIG.
And a laser beam L ₃ projected in a direction (horizontal) orthogonal to these laser beams L ₁ , L ₄ and L ₂ .

The laser projecting device 11 includes a rotation motor 66.
Is rotated at a predetermined speed by being supplied with electric power when the main switch is turned on, the rotation of the motor 66 is rotated through the pinion 67 and the transmission gear 69.
The rotating light projecting portion 15 is thereby rotated relative to the hollow member 20. Therefore, the laser projecting device 11
The laser beam L ₁ emitted from the objective lens 32 is deflected by 90 ° by the penta prism 35, and the rotary light projecting unit 15
The laser beam L ₃ can be continuously emitted while rotating the laser beam in the horizontal direction. As a result, the laser light beam L ₃ having a circular cross section is continuously emitted from the laser projecting device 11 while maintaining a constant level, that is, it is possible to form a horizontal plane (horizontal reference plane). An operator can perform an operation such as putting a mark on a locus through which a laser beam having a substantially circular cross-section that irradiates a pillar or the like of a building passes.

When adjusting the tilt angle which differs depending on the place where the laser projecting device 11 is placed, a switch (not shown) is operated to drive the first and second level adjusting motors 4.
4 and 75 are rotationally driven. For example, when driving the first level adjustment motor 44, the rotation is transmitted to the adjustment screw 45 via the pinion 49 and the transmission gear 50,
The rotation of the adjusting screw 45 moves the adjusting nut 46 up and down. At that time, since the roller 40 biased in a predetermined direction by the tension spring 52 is elastically contacted with the protrusion 47 of the adjusting nut 46, the roller 40 is
The hollow member 20 can be rotated about the spherical center of the bulging portion 21 via the. Further, when the second adjusting motor 75 is driven, the rotation thereof is performed by the pinion 76 and the transmission gear 77.
Is transmitted to the adjustment screw 79 via the, and the adjustment nut 80 moves up and down by the rotation of the adjustment screw 79. At that time, the protrusion 81 of the adjusting nut 80 is
Since the roller 41 biased in a predetermined direction by the tension spring 52 is elastically contacted, the hollow member 20 can be rotated about the spherical center of the bulging portion 21 via the roller 41. The tilting position of the hollow member 20 with respect to the horizontal direction at the time of laser beam irradiation is determined by these rotation adjustments.

When the focal point is aligned with the irradiation target such as the wall or column of the laser beam to be irradiated, the focusing motor 59 is rotationally driven by operating a switch (not shown). This rotation is transmitted to the focusing screw 56 via the pinion 60 and the transmission gear 61. Then, since the focusing nut 57 is moved up and down by the rotation of the focusing screw 56,
This vertical movement is transmitted to the sliding member 30 via the link 62 fixed to the focusing nut 57. Then, the position of the focal point is adjusted while observing the spot of the laser light flux projected on the irradiation target such as a wall or a pillar.

Next, a second embodiment according to the present invention will be described with reference to FIG. In this embodiment, anamorphic prisms 25 and 26 having anamorphic magnifications of m ₁ and m ₂ are used as the prism P included in the laser beam cross-sectional shape conversion optical system 18. The anamorphic magnification m of both anamorphic prisms 25 and 26 is represented by m = m ₁ × m ₂ . In this case, the incident laser beam and the emitted laser beam can be made parallel to each other. Here, in particular, both anamorphic prisms 25 and 26 have the same anamorphic magnification (m ₂ = m ₁ ) if the same shape and the same glass material are used. At this time, it is possible to save labor at the time of manufacturing such as manufacturing different anamorphic prisms, which contributes to reduction of manufacturing cost.

By the way, generally, when the oscillation wavelength of the laser diode 23 changes due to temperature change or the like, chromatic aberration (chromatic aberration of magnification) due to the anamorphic prisms 25 and 26.
Occurs, the emission angle from the emission surface 26a changes by Δθ (see FIG. 13). For example, visible laser beam (wavelength λ
= 635 nm), it changes about 2 nm / 10 °. Therefore, it is extremely important in the laser projecting device 11 for forming the reference beam and the reference plane during surveying that the variation Δθ is made as small as possible.

Therefore, in the second embodiment, the anamorphic prisms 25 and 26 are arranged so that the bending directions of the laser beams are opposite to each other, and the glass materials are selected so as to cancel the chromatic aberrations. The above-mentioned problem regarding chromatic aberration can be solved. Table 1 shows a specific design example regarding the second embodiment. Here, the necessary anamorphic magnification m is considered to be about 4.4 (for the visible laser diode of interest). In Table 1, Design Examples 1 and 2 are cases where different glass materials are used, and Design Example 3 is a case where the same glass material is used for reference.

[Table 1]

In Design Examples 1 to 3, the magnification is determined by the incident angle, the apex angle, and the refractive index, and the chromatic aberration is determined by the relationship between the Abbe number of the anamorphic prism 25 and the Abbe number of the anamorphic prism 26. That is, when the Abbe number of the anamorphic prism 25 is ν ₁ and the Abbe number of the anamorphic prism 26 is ν ₂ , the following conditional expression (1)
If the glass material is selected so as to satisfy the above condition, the chromatic aberration can be corrected. (1) ν ₂ / ν ₁ > 1.8, ν ₂ > ν _{1 At the} apex angles α _{1 and} α ₂ , the laser beam is made to enter in parallel, and the laser beam emitted from the emission surface is 90 ° to the emission surface. This is the angle when set to be °. According to the second embodiment shown in FIG. 12, anamorphic prisms 25, 2
By setting the directions of the apexes α _{1 and} α ₂ respectively, the laser beam emitted from the laser diode 23 can be incident on the beam splitter 27 without changing the direction. Therefore, a useless space required for disposing the optical system can be omitted.

Further, as shown in FIG. 14, the anamorphic prisms 25 and 26 have apex angles α _{1 and} α ₂ of FIG.
It can also be arranged so as to face in the direction opposite to the state shown in 2. According to the third embodiment as well, similar to the second embodiment shown in FIG. 12, the laser beam emitted from the laser diode 23 can be made incident on the beam splitter 27 without changing its direction. It is possible to save a wasteful space for arranging the system.

In each of the first to third embodiments, the laser beam cross-sectional shape converting optical system 18 extends the short axis Di of the light beam having the elliptical cross section from the laser diode 23 to convert it into a circular shape. The laser beam cross-sectional shape conversion optical system 18 of the present invention is not limited to this. That is, as in the fourth embodiment shown in FIG. 15, the anamorphic prism 2
By arranging 5'and 26 ', the major axis D _O (major axis direction) of the luminous flux having an elliptical cross section can be reduced to a circular shape having the minor axis D _i as the diameter.

In each of the first to third embodiments, the anamorphic prism is used to convert the laser beam having an elliptical cross section into a substantially circular cross section. However, a cylindrical lens is used instead of this anamorphic prism. The fifth embodiment used will be described with reference to FIG. In the figure, behind the collimator lens 24, a cylindrical lens 91 having a focal length f _1, the cylindrical lens 90 of focal length f ₂ are arranged in this order. These cylindrical lenses 90 and 91 each have a positive power, are arranged so as to be in a confocal relationship with each other in one direction, and lasers having an elliptical cross section emitted from the collimator lens 24 within the range of the focal length. Only one of the major axis and the minor axis of the light beam can be changed. That is, by selecting the focal lengths f ₁ and f ₂ so that m = D ₀ / D _i = | f ₂ / f ₁ | It is possible to extend the minor axis of the laser light flux having an elliptical cross section to obtain a light flux having a substantially circular cross section.

Further, in FIG. 17, by replacing the cylindrical lens 91 of FIG. 16 with a cylindrical lens 94 having a negative power, as in the fifth embodiment described above, an elliptical cross section is formed without using an anamorphic prism. A sixth embodiment for converting the laser light flux of the above into a substantially circular cross section will be described.

[0049]

As described above, according to the present invention, a laser light beam cross section for converting a laser light beam having an elliptical cross section after being emitted from the laser light source into a substantially circular cross section in the laser optical path from the laser light source to the reflecting means. Equipped with a shape conversion optical system, we provide a laser surveying device that facilitates aiming point alignment and makes the detection sensitivity of the detector the same in any direction without complicating the optical system or increasing costs. can do.

According to the invention described in claim 5, a collimator lens for converting the laser light emitted from the laser light source into a parallel light flux is provided between the laser light source and the laser light beam cross-sectional shape conversion optical system. Since the astigmatic difference contained in the laser light beam is corrected by changing the distance between the laser light source and the collimator lens, the beam diameter cannot be reduced to a small size due to the astigmatic difference of the emitted laser light beam. A laser projecting device for forming a reference plane that can solve the problem can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an entire laser projection device according to the present invention.

FIG. 2 is a side view showing a laser beam cross-sectional shape conversion optical system and the like of the laser projection device.

FIG. 3 is an enlarged plan view showing a main part of the laser projection device.

FIG. 4 is a side view showing a first embodiment of a laser beam cross-sectional shape conversion optical system according to the present invention.

FIG. 5 is a diagram showing a laser light flux having an elliptical cross section emitted from a laser diode.

FIG. 6 is a diagram showing a laser light flux whose cross-sectional shape is converted into a substantially circular shape by a laser light flux cross-sectional shape conversion optical system.

FIG. 7 is a graph showing the correlation between the anamorphic magnification of the anamorphic prism and the apex angle.

FIG. 8 is a graph showing a correlation between an incident angle, an apex angle and a surface reflectance of an anamorphic prism.

FIG. 9 is a schematic diagram for explaining a configuration for eliminating astigmatism of an emitted laser beam.

FIG. 10 is a schematic diagram for explaining a configuration for eliminating astigmatism of an emitted laser beam.

FIG. 11 is a schematic diagram for explaining a configuration for eliminating astigmatism of an emitted laser beam.

FIG. 12 is a side view showing a second embodiment of the laser beam cross-sectional shape conversion optical system according to the present invention.

FIG. 13 is a schematic side view showing how the emission angle of a laser beam emitted from an anamorphic prism changes due to chromatic aberration.

FIG. 14 is a side view showing a third embodiment of the laser light beam cross-sectional shape conversion optical system according to the present invention.

FIG. 15 is a side view showing a fourth embodiment of the laser beam cross-sectional shape conversion optical system according to the present invention.

FIG. 16 is a side view showing a fifth embodiment of the laser light beam cross-sectional shape conversion optical system according to the present invention.

FIG. 17 is a side view showing a sixth embodiment of the laser beam cross-sectional shape conversion optical system according to the present invention.

FIG. 18 is an explanatory diagram showing a state of an emitted light beam for explaining a problem of the conventional laser projecting device.

FIG. 19 is an explanatory diagram showing a light receiving state of a light beam spot by a detector for explaining a problem of the conventional laser light projecting device.

20 is a diagram showing an output waveform when a light beam spot is received by the detector of FIG.

[Explanation of symbols]

11 Laser Projection Device 13 Projection Device Main Body 15 Rotating Projection Unit 15a Laser Light Optical Path 20a 20b Laser Light Optical Path (First Optical Path, Second Optical Path) 18 Laser Beam Cross Section Shape Conversion Optical System 20 Hollow Member 23 Laser Diode ( Laser light source) 24 Collimating lens 25 26 Anamorphic prism 27 Polarizing beam splitter 35 Penta prism (reflecting means) 90 91 Cylindrical lens

Claims (11)

[Claims] 1. A reference plane forming laser projecting apparatus for forming a reference plane by irradiating a laser beam from a laser light source with a reflecting means and irradiating the laser beam in rotation, wherein a laser beam optical path from the laser light source to the reflecting means is provided. A laser projecting device for forming a reference plane, comprising a laser beam cross-sectional shape conversion optical system for converting a laser light beam having an elliptical cross section after being emitted from the laser light source into a substantially circular cross section. 2. The reference plane forming laser according to claim 1, wherein the laser beam cross-sectional shape conversion optical system is an anamorphic optical system in which an elliptical laser beam from a laser light source is extended in a minor axis direction to be a circular shape. Floodlight device. 3. The reference plane forming laser projection system according to claim 1, wherein the laser beam cross-sectional shape conversion optical system is an anamorphic optical system in which the major axis direction of the elliptical laser beam from the laser light source is reduced to a circular shape. Light equipment. 4. The laser beam cross-sectional shape conversion optical system according to claim 1, which is an anamorphic optical system including a pair of cylindrical lenses arranged in a confocal relationship with different focal lengths. A laser projection device for forming a reference plane, wherein each focal length is set so as to satisfy the following conditional expression (1) with respect to the magnification m. (1) m = D ₀ / D _i = | f ₂ / f ₁ | where D ₀ : major axis dimension of elliptical laser beam from laser light source, D _i : elliptical laser beam from laser source Short-axis dimension, f ₁ : focal length of one of the pair of cylindrical lenses located on the laser light source side, f ₂ : focal length of the other of the pair of cylindrical lenses. 5. The collimator lens for converting a laser light flux emitted from the laser light source into a parallel light flux, is provided between the laser light source and the laser light flux cross-sectional shape conversion optical system according to claim 1. A laser projecting device for forming a reference plane that corrects the astigmatic difference contained in the laser beam by changing the distance between the collimating lens and the collimating lens. 6. The laser projecting device for forming a reference plane according to claim 1, wherein the laser light source is a laser diode that emits visible light. 7. The laser light flux cross-sectional shape conversion optical system according to claim 1, wherein the laser light flux cross-sectional shape conversion optical system is a pair of anamorphic prisms arranged on the optical axis of the laser light flux from the laser light source. A laser projecting device for forming a reference plane, which satisfies the following conditional expression (1), where v ₁ and v ₂ are set in order from the laser light source side. (1) ν ₂ / ν ₁ > 1.8, ν ₂ > ν ₁ 8. The laser light flux cross-sectional shape conversion optical system according to claim 1, wherein the laser light flux cross-sectional shape conversion optical system is a pair of anamorphic prisms arranged on the optical axis of the laser light flux from the laser light source. A laser projecting device for forming a reference plane, which is arranged so that the bending directions of the two are opposite to each other. 9. The laser light optical path according to claim 1, wherein the laser light optical path includes a first optical path orthogonal to each other, in which the laser light source is located, and a second optical path for guiding the laser light flux from the laser light source to the reflecting means. Laser projecting device for forming a reference plane. 10. The reference plane forming device according to claim 9, wherein a polarization beam splitter is provided at the intersection of the first and second optical paths to deflect the laser beam emitted from the laser light source toward the reflecting means. Laser projector. 11. The laser projecting device for forming a reference plane according to claim 10, wherein the laser beam cross-sectional shape conversion optical system is provided between the laser light source and the polarization beam splitter.