JPH08193832A - Apparatus for projecting beam - Google Patents

Abstract

PURPOSE: To set the optimum or a required beam diameter at a required distance. CONSTITUTION: In a laser survey apparatus projecting a laser luminous flux from a semiconductor laser 23 approximately as beams of a parallel luminous flux, a zoom beam expander ZB is provided in an optical path of the laser luminous flux from the semiconductor laser 23. The expander ZB changes a beam diameter of the laser luminous flux from the semiconductor laser 23 with a variable expansion rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam projection device for measuring a distance, measuring an angle, or forming a reference plane by a projected beam of a substantially parallel light beam.

[0002]

[Prior Art and its Problems] In the field of civil engineering,
Using a laser surveying device (so-called laser planer) that scans the laser beam from the rotating light projection unit toward the surveying object around the device body and forms a reference plane by the laser beam, Standardization and height measurement are performed by measuring the height of the spot. This laser surveying device can measure, for example, from a short distance of 0.5 to 1.5 m to 100
Used in a wide range up to a distance of ~ 200m.

By the way, the diameter of the projected laser light changes due to diffraction and is not a perfect parallel light beam. Therefore, for example, when the light beam reaches far, it is necessary to increase the beam diameter at the time of emission. On the contrary, when used at a short distance, it is advantageous to reduce the beam diameter at the time of emission, because there are few errors when visually determining the position. Further, if the beam diameter is not properly set in accordance with the use range, for example, when the beam height position is detected by the detector, the detection sensitivity may vary depending on the measurement distance.

As can be seen from this, in order to make full use of the laser surveying device in the field or the like, it is necessary to be able to change the beam diameter of the emitted laser light beam and to easily change the beam diameter. However, no conventional laser surveying device has such means.

[0005]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the above problems in the conventional laser surveying apparatus, and provides a beam projection apparatus capable of setting an optimum or desired beam diameter at a required distance. The purpose is to do.

[0006]

SUMMARY OF THE INVENTION The present invention for achieving the above object is directed to a beam projection apparatus for projecting a light beam from a light source as a beam of a substantially parallel light beam. Change the beam diameter of the light flux,
It is characterized by having a variable beam diameter optical system in which the beam diameter expansion ratio is variable.

Further, according to the present invention, in a beam projection device for projecting a light beam from a light source as a substantially parallel light beam, the beam of the emitted light beam is located in the optical path of the light beam from the light source, and the light-shielding diameter for this light beam is changed. It features a variable aperture that changes the diameter.

[0008]

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 an entire laser surveying apparatus (beam projection apparatus) to which the present invention is applied. The laser surveying device 11 has a substantially cylindrical housing 12 and a light projecting device 13 provided inside the housing 12. A cylindrical transparent member 16 surrounding the rotary light projecting unit 15 above the light projecting device 13 is fixed above the housing 12, and a driving battery (not shown) for the laser surveying device 11 is housed below the transparent member 16. The battery case 17 is fixed.

The housing 12 has a sliding guide portion 19 having a substantially conical shape at the center of the upper portion and a circular hole 12a at the center of the lower portion. The circular hole 12a causes a laser beam from above to be emitted to the outside below the laser surveying device 11 in a state of being matched with the circular hole 17a formed in the central portion of the battery case 17. 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 light projecting device 13 has a hollow member 20 having a hollow portion along the vertical direction, and a rotary light projecting portion 15 which is rotatably supported above the hollow member 20 via a bearing 10. ing. Swelling portion 21 of the hollow member 20
Is formed by the projecting laser beam L ₃ by tilting the rotary light projecting unit 15 (light projecting device 13) in all directions around the rotation axis a with the spherical portion abutting on the sliding hole 19a. It is supported so that the reference plane 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. A semiconductor laser 23 that emits a visible laser light flux, a collimator lens 24 that converts the light flux from the semiconductor laser 23 into a parallel light flux having an elliptical cross section, and a light flux from the collimator lens 24 that are circular parallel light are provided in the laser light optical path 20a. A laser beam cross-sectional shape conversion optical system 18 for converting into a light flux is provided.

A polarization beam splitter 27 that receives the laser beam from the collimator lens 24 is provided in the laser beam optical path 20b located on the extension of the rotation axis a of the rotary light projecting unit 15. This polarization beam splitter 27 is shown in FIG.
As shown in FIG. 3, it has a polarization splitting surface 27a and a 1/4 λ plate 28, and the 1/4 λ plate 28 is attached so that its axis direction is 45 ° with respect to the polarization direction of the incident light. There is.
Further, the 1/4 λ plate 28 has a semi-transparent surface with a reflectance of about 10 to 20%, which transmits a laser beam toward the penta prism 35 at a predetermined ratio and reflects the remaining laser beam toward the polarization beam splitter 27 on the upper surface. It has a membrane 28a. Below the polarization beam splitter 27, the wedge prism 2
9a and 29b are provided.

As shown in FIG. 1, the rotary light projecting section 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 the laser beam optical path 15a.
15 having a diameter larger than the laser light optical path 15a continuous to
b. A light projecting window 33 for projecting the laser light flux reflected and deflected by the penta prism 35 housed inside is formed on the side wall of the housing portion 15b. Further, the upper portion of the storage portion 15b is opened, and the optical axis a of the laser light optical path 15a is aligned with the center of the light transmitting member 36 fitted in the circular hole 16a in the upper center of the transparent member 16.

The penta prism 35 is a rotary light projecting unit 15.
Further, it is fixed so as to rotate integrally with the light projecting portion 15. The penta prism 35 has a light incident surface 35c on which a laser beam is incident, and the first reflecting surface 3 having a semi-transmissive film 14 having a required reflectance and forming a predetermined angle with the light incident surface 35c.
5a and. The penta prism 35 is also the first
A second reflecting surface 35b for reflecting the laser light flux reflected by the reflecting surface 35a in a direction orthogonal to the rotation axis a;
It has a light incident surface 35c which emits the laser beam reflected by the reflecting surface 35b and a light emitting surface 35d which forms 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. A wedge prism 34 is attached to the first reflecting surface 35a with the semipermeable membrane 14 interposed therebetween. The wedge-shaped prism 34 has a hypotenuse as the first reflecting surface 35a.
1 attached to the upper surface of FIG.
Are parallel to the light incident surface 35c of the pentaprism 35.

The hollow member 20 integrally includes a drive arm 37 extending rightward in FIG. 2 and a drive arm 39 (FIG. 3) orthogonal to the drive arm 37 in the depth direction of the drawing. are doing. The drive arms 37 and 39 are formed by inclining downward from the uppermost part of the bulging portion 21, and have rollers 40 and 41 attached to the tip ends of the driving arms 37 and 39 so as to match the spherical center of the bulging portion 21. ing.

A bracket 42 having a support hole 42a is provided on the inner wall of the housing 12 so as to project toward the inner circumference of the housing 12. A support hole 43 is formed in the upper wall 12b at a position facing the support hole 42a. Shafts at both ends of the adjusting screw 45 are rotatably fitted in the support holes 42a and 43. A first level adjusting motor 44 is fixed to the bracket 42, and a pinion 49 fixed to the rotation shaft of the motor 44.
Engages with a transmission gear 50 fixed to the lower end of the screw 45. An adjusting nut 46, which constitutes a feed screw mechanism together with the screw 45 and whose relative rotation with respect to the housing 12 is restricted, is screwed into the screw 45. An operating pin 47 fixed to the outer periphery of the nut 46 is in contact with the roller 40 from above.

As shown in FIG. 3, the inner wall of the housing 12 is provided with a bracket 78 protruding toward the inner periphery. A gear support hole (not shown) formed in the bracket 78 and a gear support hole (not shown) formed at a position facing the gear support hole of the upper wall 12b are provided at both ends of the adjusting screw 79. The shaft is rotatably fitted. The pinion 76 fixed to the rotary shaft of the second level adjusting motor 75 fixed to the bracket 78 meshes with the transmission gear 77 fixed to the lower end of the screw 79. This screw 79 is
An adjusting nut 80 whose relative rotation with respect to the housing 12 is restricted is screwed into the feed screw mechanism. An operating pin 81 fixed to the outer circumference of the nut 80 is in contact with the roller 41 from above.

The housing 12 has on its inner wall a support projection 51 which is provided in a direction that bisects the angle formed by the drive arms 37 and 39 orthogonal to each other. The hollow member 20 includes a tension spring 5 provided between the support protrusion 51 and the hollow member 20.
The rollers 4 are urged upward by the same force by 2 respectively.
0 and 41 are elastically contacted with the operating pins 47 and 81 from below. That is, the hollow member 20 has the lower portion thereof with the bulging portion 21 supported by the sliding hole 19a.
Since it is urged toward 1, it is possible to adjust the rotational position in the horizontal direction by operating pins 47 and 81 that are moved up and down by motors 44 and 75 that are driven based on signals from a microcomputer (hereinafter referred to as microcomputer) 82. Has been done. Brackets 70 and 71 are provided below the hollow member 20 so as to project in the opposite directions to the arms 37 and 39, and level detection sensors 72 and 73 are attached to the brackets 70 and 71, respectively. . The sensor 7
The detection signal from 2, 73 is sent to the microcomputer 82.

A bracket 65 is provided at the uppermost portion of the hollow member 20 so as to project outward. A rotation motor 66 is fixed to the bracket 65, and a pinion 67 fixed to the rotation shaft of the motor 66.
, Meshes with the transmission gear 69 fixed to the outer periphery of the rotary light projecting portion 15. Therefore, when the motor 66 is rotationally driven based on the signal from the microcomputer 82, the rotary light projecting portion 15 is relatively rotated with respect to the hollow member 20 via the pinion 67 and the transmission gear 69. Further, a rotation detection sensor 83 is provided upward on the side opposite to the uppermost bracket 65 of the hollow member 20. This rotation detection sensor 83
A predetermined pattern (not shown) provided on the upper side, that is, on the back surface of the transmission gear 69 is irradiated with a light beam, and the reflected light is received and then 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 input of the received light signal.

On the other hand, above the polarization beam splitter 27 in the laser beam optical path 20b, a first lens group (first movable lens group) 31 having positive power and a second lens group (second lens group) having negative power (first lens group) Two movable lens groups) 25 and a third lens group (fixed lens group) 32 having a positive power are provided. The third lens group 32 is fixed to the pentaprism 35 side in the laser light optical path 20b. In addition, the first lens group 31 and the second lens group 25 are
0b, each of which is supported by a slidable cylindrical member 30a, 30b.
Can be moved back and forth in the optical path 20 by moving. These first, second and third lens groups 31, 25,
By 32, the beam diameter of the laser light flux emitted from the semiconductor laser 23 and converted into the parallel light flux by the collimator lens 24 is expanded or reduced by changing the expansion ratio (beam diameter expansion ratio) and is given to the pentaprism 35. A beam expander ZB (variable beam diameter optical system) is configured. The first, second, and third lens groups 31 at the time of zooming of the zoom beam expander ZB,
Data relating to the movement loci of 25 and 32 is obtained by the microcomputer 82.
Stored in advance.

A bracket 53 protruding outward is provided on the lower portion of the hollow member 20, and a bracket 55 facing the bracket 53 is formed on the upper portion of the bracket 53. These brackets 53, 5
5 includes gear support holes 53a and 55a facing each other.
The shaft portions at both ends of the lens moving screw 56 are rotatably fitted in the gear supporting holes 53a and 55a. The pinion 60 fixed to the rotary shaft of the lens moving motor 59 fixed to the bracket 53 meshes with the transmission gear 61 fixed to the lower end of the screw 56. A lens moving nut 57, which constitutes a feed screw mechanism together with the screw 56, is screwed onto the screw 56. Further, an insertion window 63 is formed in the wall portion of the hollow member 20 corresponding to the cylindrical member 30a.
Both ends of the cylindrical member 30a and the lens moving nut 57.
A link 62 fixed to each of them penetrates. Therefore, by driving the lens moving motor 59 based on the signal of the microcomputer 82, the cylindrical member 3 is driven through the feed screw mechanism.
0a can be moved up and down to move the first lens group 31 forward and backward with respect to the third lens group 32 (second lens group 25).

Although not shown in the drawing, in the depth direction of the paper of FIG. 1, it has the same structure as the feed screw mechanism for moving the cylindrical member 30a, and the cylindrical member 30b is connected to the laser beam optical path 20.
A feed screw mechanism is provided for moving within b. By driving the feed screw mechanism (not shown) based on a command from the microcomputer 82, the cylindrical member 30b, that is, the second lens group 25 can be moved forward and backward with respect to the third lens group 32. Therefore, by driving the two feed screw mechanisms based on the command of the microcomputer 82 having the predetermined movement trajectory data, the first and second lens groups 31 and 25 have a predetermined relationship in the laser beam optical path 20b. It is possible to project the laser light beam L ₃ whose beam diameter has been expanded or reduced by moving it with the rotary projection unit 15 (see FIGS. 4 to 6).

4 to 6 show an example of the lens structure of the zoom beam expander ZB used in this embodiment.
FIG. 4 shows the minimum variable magnification state of the beam diameter, FIG. 6 shows the maximum variable magnification state of the beam diameter, and FIG. 5 shows the state during the transition from the state of FIG. 4 to the state of FIG.

The first lens group 31 and the third lens group 32 are cemented (bonded) lenses, and the third lens group 32 has a larger diameter than the first lens group 31 and the second lens group 25. Has been done. This zoom beam expander ZB
Table 1 shows specific numerical data of the above, and FIGS. 7 to 9 show longitudinal aberrations in the states of FIGS. 4 to 6, respectively. The above lens configuration diagram and aberration diagram are represented by incident light up to an incident field angle of 1 °. The reference design wavelength in this example is 680 nm.
Is.

In FIGS. 4 to 6, the longitudinal aberration is an aberration when light is incident from the left side of the figures. 7 to 9, ER is an exit pupil diameter, B is an exit angle, S is a sagittal,
M indicates meridional, and the solid line, the fine broken line, and the large broken line indicate aberrations at wavelengths of 680 nm, 660 nm, and 700 nm, respectively. The unit of spherical aberration and astigmatism is diopter, and the unit of lateral chromatic aberration is [°].

Further, in Table 1, R is the radius of curvature of the surface sequentially located from the light source side (left side) in the figure, D is the wall thickness or lens interval of the lenses sequentially located from the light source side, and N is from the light source side. Refractive index of sequentially positioned lenses at 680 nm, νD
Is the Abbe's number at the d-line of the lens sequentially positioned from the light source side, and ND is the refractive index at the d-line.

Γ is an angular magnification, which has a reciprocal relationship (M = 1 / γ) with the magnifying power M of the light beam. The angular magnification γ in FIG. 4 is
6 and the angular magnification γ in FIG. 5 is 1.0.
The angular magnification γ at is 0.5. Also, the exit pupil diameter ER
Is the relationship of ER = incident light beam diameter / γ, and the exit angle B
Is in the relation of B = W × γ (B is the incident angle of view). That is, the zoom beam expander ZB having the above lens configuration
Is the beam diameter of the incident light beam with a diameter of 10 mm from 0.5 times to 2.0
It is configured to be convertible to double the diameter (5.0 mm to 20 mm).

[0028]

[Table 1] Surface No. RDN νD ND 1 86.889 2.500 1.65345 50.9 1.65844 2 -83.222 1.400 1.79363 25.4 1.80518 3 -364.240 D3 4 1312.040 1.400 1.76648 49.6 1.77250 5 56.933 1.500 6 -55.384 1.400 1.76648 49.6 1.77250 7.8 495.227 1.79363 25.4 1.80518 9 68.900 3.500 1.65345 50.9 1.65844 10 -99.869 −

In Table 1, D3 is the lens spacing of the first lens group 31 with respect to the second lens group 25, which are 62.480, 42.850, and 3.600 corresponding to the states of FIGS. D7 is the third lens group 32 of the second lens group 25
Is a lens interval corresponding to, and is 3.000, 42.620, and 62.430 corresponding to the states of FIGS. 4 to 6, respectively.

The laser surveying instrument 11 having the above construction operates as follows. First, the laser surveying instrument 11 is arranged at a desired position via a tripod. In the unadjusted state, the axis of the rotary light projecting portion 15 (rotating axis a) generally does not coincide with the vertical line, and the level detection sensors 72 and 73 are not in the horizontal state. When the drive switch is turned on in this state, the microcomputer 82 rotationally drives the first and second level adjusting motors 44 and 75 based on the calculated angle deviation. For example, when the adjustment motor 44 is rotationally driven,
The screw 45 is rotated and the level adjusting nut 46 is moved up and down. At this time, since the roller 40 biased by the tension spring 52 is elastically contacted with the operation pin 47 of the nut 46, the hollow member 20 is centered on the spherical center of the bulging portion 21 via the roller 40. Rotated and rotated light projecting unit 1
5 is tilted with respect to the vertical direction. Also, the adjustment motor 7
When 5 is driven, it is transmitted to the level adjusting screw 79 and the level adjusting nut 80 is moved up and down. At this time, the tension spring 52 is attached to the operating pin 81 of the nut 80.
Since the roller 41 urged by is elastically contacted, the rotary light projecting portion 15 is tilted with respect to the vertical direction as described above.

When the light projecting device 13 is tilted and the leveling proceeds, the detection values from the level detection sensors 72 and 73 approach the reference horizontality, and the angle deviation finally becomes 0.
The light projecting device 13 (rotary light projecting unit 15) is adjusted by the tilt adjustment.
The horizontal position at the time of projecting the laser beam is determined, and the leveling work is completed.

In this leveling work completed state, the microcomputer 8
When a drive signal is output from the semiconductor laser 23 and the semiconductor laser 23 starts oscillating, the laser light flux emitted from the semiconductor laser 23 is converted into a parallel light flux having an elliptical cross section by the collimator lens 24, and then the laser light cross sectional shape conversion is performed. It is converted into a circular parallel light beam by the optical system 18, and is split by the polarization beam splitter 27 into a light beam L ₁ directed upward and a light beam L ₂ directed downward.

In this case, the laser light beam L ₀ incident on the polarization beam splitter 27 has an S-polarized component having a vibration direction perpendicular to the incident surface of the polarization splitting surface 27a and has a P-polarization component.
If the light is linearly polarized light having no polarization component, the laser light flux L ₀
Is reflected by the polarization splitting surface 27a and is deflected by 90 °, and goes upward in FIG. At this time, since the 1/4 λ plate 28 is attached to the polarization beam splitter 27 so that the axis direction is 45 ° with respect to the vibration direction of the light, the laser beam L
₀ is a circularly polarized laser light beam L ₁ that passes through the 1/4 λ plate 28.
And goes to the pentaprism 35. In addition, the semipermeable membrane 2
The laser light flux L ₁ reflected by 8a is again transmitted through the 1/4 λ plate 28, is then converted into linearly polarized light of a P-polarized component having vibration in a direction orthogonal to the time of incidence, and is transmitted through the polarization separation surface 27a to be laser light. The light beam L ₂ goes downward in the figure, passes through the wedge prisms 29a and 29b, and then is emitted to the outside of the lower portion.

On the other hand, the upward laser beam L ₁ passes through the first, second, and third lens groups 31, 25, 32, and after passing through the light incident surface 35c of the pentaprism 35, the first, second The light is reflected by the two reflecting surfaces 35a and 35b in order, deflected by 90 ° in the course, and emitted from the light emitting surface 35d in a substantially horizontal direction. Of the laser light flux L ₁ , the first reflecting surface 35
Except for the light beam reflected by a at a predetermined ratio, the laser light beam is transmitted through the half mirror surface formed by the first reflecting surface 35a and the wedge-shaped prism 34 without changing the course, and is a laser light beam coaxial with the laser light beam L _1. The light is projected upward as L ₄ . In this laser projection state, when the rotation motor 66 is driven based on the drive signal from the microcomputer 82, the rotary light projecting unit 15 starts to rotate about the vertical rotation axis a, so that the pentaprism 35 moves in the horizontal direction. A horizontal reference plane is formed by the laser light flux L ₃ emitted at.

The laser surveying device 11 is, for example, 0.5 to 1.5 m.
It is used for standardization and height measurement in a wide range from a short distance of 100 m to a long distance of 100 to 200 m, but the beam diameter of the laser light beam emitted as a parallel light beam changes due to diffraction. For this reason, for example, the beam diameter at the time of emission is made thicker in order to reach the laser beam at a distance, or the beam diameter at the time of emission is made thinner in order to reduce the error in the visual confirmation of the position at a short distance. There is a need.

According to the laser surveying instrument 11, by operating an adjusting switch (not shown), the zoom beam expander ZB is driven based on a command from the microcomputer 82, so that the laser light flux at the time of emission can be changed to a desired beam. Since the diameter can be converted, it is possible to meet the above demand.

That is, in the case of adjusting the laser light flux to reach far, the first and second lens groups 31 and 25 are changed to the third lens group 32 by operating the adjustment switch.
Is moved relative to a predetermined trajectory. As a result, when the zoom beam expander ZB is in the state shown in FIG. 5, the angular magnification γ is 1/2, that is, the expansion rate M of the light flux is 2 times. When the beam diameter is further increased, the zoom beam expander ZB is further driven to drive the first and second lens groups 3
1, 25 are further moved relative to each other in a predetermined locus. As a result, when the zoom beam expander ZB is in the state shown in FIG. 6, the angular magnification γ is 1/4 of the initial value, that is, the expansion rate M of the luminous flux.
Is 4 times. On the contrary, when the laser surveying instrument 11 is used in a relatively close range, the zoom beam expander ZB is driven by operating the adjustment switch in the opposite direction to the above-mentioned enlargement to reduce the beam diameter.

As described above, the laser surveying instrument 11 drives the zoom beam expander ZB based on the movement locus data of the lens stored in the microcomputer 82, and enlarges or reduces the beam diameter within the above range as required to obtain a desired beam diameter. It is possible to project a laser beam having a beam diameter of. Moreover, since the zoom beam expander ZB captures and emits all the laser light flux emitted from the semiconductor laser 23, the light amount is not lost when the beam diameter is converted.

Therefore, the beam diameter of the projected light beam can be easily set to be optimum or desired at a required distance, and the usage condition in the field or the like can be always improved. As a result, for example, when detecting the beam height position by the detector, it is possible to eliminate the fluctuation of the detection sensitivity caused by the measurement distance,
In addition, it becomes possible to improve the visibility by visual inspection.

In the first embodiment, the third lens group 32 is fixed, and the first lens group 31 and the second lens group 2 are fixed.
Although 5 is configured to be movable, if focusing is performed by moving the third lens group 32 having the largest diameter located on the exit side,
It is possible to obtain the minimum beam diameter at any distance,
Further, there is an effect that the focusing does not shift due to the operation of changing the exit beam diameter.

Further, in the first embodiment, the zoom beam expander ZB is driven by operating the adjustment switch (not shown), but by providing the laser surveying device 11 with a predetermined receiving device, the remote controller ( Zoom beam expander ZB by remote control (not shown)
Can be driven based on predetermined locus data regarding lens movement, and the beam diameter can be enlarged or reduced.

Further, the laser surveying device 11 of the first embodiment is provided with the zoom beam expander ZB composed of the first, second and third lens groups 31, 25 and 33. For example, it is also possible to mount a beam expander B composed of two groups, front and rear. The beam expander B is composed of, for example, first and second lens groups 90 and 91 each having a positive power and a negative power, which are fixed in a laser light optical path 20b (see FIG. 1) in a predetermined relationship. can do.

A second embodiment of the laser surveying instrument which can be preferably used when such a beam expander B, that is, one having a constant expansion rate is provided in the optical path will be described. The laser surveying device 11 'does not change the beam diameter by the zoom beam expander ZB as in the first embodiment, but changes the beam diameter by a variable diaphragm arranged in the laser optical path. This variable diaphragm has a known structure, and is operated by a drive mechanism (not shown) to change the beam diameter by changing the light-shielding diameter for the laser beam.

As shown in FIG. 10, the variable diaphragm 84 is provided between the polarization beam splitter 27 and the first lens group 90 in the laser light optical path 20b (see FIG. 1) or between the second lens group 91 and the pentaprism 35. It can be provided between. By operating the variable diaphragm 84 by switch operation or manually, the laser light flux L ₁ is narrowed,
It is possible to convert the beam diameter of the laser light flux L ₃ emitted from the pentaprism 35 into large and small. The variable diaphragm 84 can be provided on the light exit side (rear of the optical path) of the pentagonal prism 35, as shown by the chain double-dashed line. In that case, the laser beam L ₃ emitted from the penta prism 35
Laser beam L ₃ emitted from the rotary light projecting unit 15
The beam diameter of can be converted into large or small. As described above, according to the second embodiment, although there is a slight loss in the amount of emitted light, it is possible to obtain substantially the same effect as that of the first embodiment using the zoom beam expander ZB.

[0045]

As described above, according to the present invention, it is possible to easily set the beam diameter of a projected light beam to be optimum or desired at a required distance, and to be used in the field or the like. Can always be good. As a result, for example, when the beam height position is detected by the detector, it is possible to eliminate the fluctuation of the detection sensitivity caused by the measurement distance, and it is also possible to improve the visual visibility.

[Brief description of drawings]

FIG. 1 is a sectional view showing an entire laser surveying instrument according to the present invention.

FIG. 2 is an enlarged configuration diagram showing a main optical system of the laser surveying instrument.

FIG. 3 is an enlarged plan view showing a main part of the laser surveying instrument.

FIG. 4 is a lens configuration diagram showing a minimum beam diameter variable magnification state of the zoom beam expander according to the present invention.

FIG. 5 is a lens configuration diagram showing a state in which a beam diameter is enlarged by the zoom beam expander.

FIG. 6 is a lens configuration diagram showing a maximum beam diameter variable magnification state of the zoom beam expander.

FIG. 7 is a longitudinal aberration diagram corresponding to the zoom beam expander in the state of FIG.

FIG. 8 is a longitudinal aberration diagram corresponding to the zoom beam expander in the state of FIG.

9 is a longitudinal aberration diagram corresponding to the zoom beam expander in the state of FIG.

FIG. 10 is an enlarged configuration diagram of a main optical system showing a second embodiment of the laser surveying device according to the present invention.

[Explanation of symbols]

11 11 'Laser surveying device (beam projection device) 15 Rotating light projecting part 23 Semiconductor laser (light source) 25 Second lens group 31 First lens group 32 Third lens group 35 Penta prism (reflecting means) 84 Variable aperture a Rotating shaft ZB zoom beam expander (variable beam diameter optical system)

Claims (12)

[Claims] 1. A beam projection device for projecting a light beam from a light source as a substantially parallel light beam, wherein the beam diameter is increased by changing the beam diameter of the light beam from the light source located in the optical path of the light beam. A beam projection apparatus comprising a variable-diameter variable-magnification optical system with variable rate. 2. The beam diameter variable magnification optical system according to claim 1, wherein the first lens group having positive power, the second lens group having negative power, and the positive power, which are sequentially arranged from the light source side. A beam projection apparatus that is a zoom beam expander that includes a third lens group that has, and that changes the relative positions of the first, second, and third lens groups to perform zooming. 3. The lens unit according to claim 2, wherein the first lens unit is a lens unit having a positive power and supported in the optical path so as to move forward and backward, and the third lens unit is a negative lens unit fixed in the optical path. A beam projecting device which is a lens group having a power of, and the second lens group is a lens group which is supported between the first and third lens groups so as to be capable of advancing and retracting. 4. The beam projection device according to claim 2, further comprising a reflecting means on the light beam exit side of the zoom beam expander for reflecting the light beam from the zoom beam expander into a substantially parallel light beam. 5. The beam projection device according to claim 1, wherein a collimator lens for converting a light beam from the light source into a substantially parallel light beam is provided between the light source and the beam diameter variable magnification optical system. 6. A beam projection device for projecting a light beam from a light source as a substantially parallel light beam, wherein the beam diameter of an emitted light beam is changed by being located in an optical path of the light beam from the light source and changing a light shielding diameter for the light beam. A beam projection device comprising a variable aperture for controlling the beam. 7. The optical path according to claim 6, wherein the optical path includes a first lens group having a negative power and a second lens group having a positive power, which are sequentially arranged from the light source side.
A beam projection device provided with a beam expander capable of changing a beam diameter by changing a relative position of a lens group. 8. The beam projection device according to claim 7, wherein the variable diaphragm is provided in an optical path between the light source and the beam expander. 9. The beam projection device according to claim 7, further comprising a reflecting means on the light beam exit side of the beam expander for reflecting the light beam from the beam expander into a substantially parallel light beam. 10. The variable diaphragm according to claim 9,
A beam projection device provided in an optical path between the reflecting means and the beam expander. 11. The variable diaphragm according to claim 9,
A beam projection device provided on the light exit side of the reflecting means. 12. The reflecting means according to claim 4 or 9, wherein the reflecting means is provided in a light projecting portion rotatable about a rotation axis.
A beam projecting device, wherein a beam from the reflecting means is rotationally projected by a rotation of the light projecting portion in a direction substantially orthogonal to the rotation axis to form a reference plane.