JPH08240429A - Beam projector - Google Patents

Abstract

PURPOSE: To provide a beam projector whose focusing can be easily performed by providing a beam expander to give a beam of light to a pentaprism by expanding a beam diameter of the beam of light from a semiconductor laser and an adjusting means to adjust a relative position between these first and second lens groups. CONSTITUTION: A laser surveying device 11 can change the relative position between both by raising and lowering a cylinder member 30 through a feed screw mechanism by driving a lens moving motor 59 on the basis of a signal of a microcomputer 82. Therefore, a laser beam of light from a semiconductor laser 23 converted into a parallel beam of light through a collimator lens 24 is given to a pentaprism 35 by expanding a beam diameter, and a beam waist position of the laser beam of light projected outward from a rotary light projecting part 15 can be easily moved and adjusted so as to become optimal or desirable at a necessary distance. Therefore, service condition of the laser surveying device 11 in the field or the like can be always improved.

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]

2. Description of the Related Art In the field of civil engineering and construction, a laser surveying device (so-called laser planer) for scanning a laser beam from a rotating light projecting part toward a surveying object around the device body to form a reference plane by the laser beam is known. ) Is used to measure the height of the spot of the laser light that has reached the object to be surveyed, and reference is made and height is measured. This laser surveying device is, for example, 100 to 20 from a short distance of 0.5 to 1.5 m.
Used in a wide range up to a distance of 0 m. Also,
Conventionally, a helium neon laser (He-Ne laser) is used as a light source in such a laser surveying instrument, but in recent years, a semiconductor laser (L
Devices using D) have become known.

Such a laser surveying device is often used in a wide temperature range, and the oscillation wavelength of the semiconductor laser, which is a light source, fluctuates due to temperature changes. In that case, since the laser light flux emitted through the lens has chromatic aberration,
The movement of the beam waist position due to chromatic aberration needs to be corrected by focusing. Therefore, in order to provide a laser surveying instrument that can be fully utilized outdoors, etc., it is necessary to have a structure capable of easily focusing the emitted laser beam.

Conventionally, a laser beam from a semiconductor laser is
A laser surveying instrument has been proposed which focuses an emitted laser beam by converging it with a condensing lens, then reflecting it with a prism to enter an objective lens, and advancing and retracting this objective lens in the optical axis direction. In such a structure, since the prism is located in the optical path of the laser beam from the semiconductor laser, it is difficult to match the optical axes of the condenser lens and the objective lens that moves by focusing.

Further, since the condensing performance of the light beam is determined by diffraction, in order to make the laser surveying instrument usable over a long distance, the aperture of the objective lens is made large and the laser surveying instrument is made thick according to the required reaching distance. There is no choice but to configure so that the light flux can be emitted. However, with such a configuration, the load of the focusing drive system for advancing and retracting the large-diameter objective lens becomes large, and a motor or the like having a large output is required.

[0006]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the above-mentioned problems in the conventional laser surveying instrument, and can easily perform focusing at a required distance, and further, this focusing is of a small size which does not easily cause deviation of the optical axis. It is an object of the present invention to provide a beam projection device that can be performed by an optical system. Another object of the present invention is to provide a beam projection apparatus capable of reducing the output of the drive system when focusing is performed by a drive system such as a motor.

[0007]

SUMMARY OF THE INVENTION The present invention for achieving the above object is a beam projection device for reflecting a light beam from a light source by a reflecting means and projecting the light beam as a substantially parallel light beam. Collimator lens for converting into a light flux; in the optical path between the collimator lens and the reflecting means, a first lens group having negative power located on the collimator lens side and a second lens group having positive power located on the reflecting means side. A lens group, and a beam diameter converting optical system for enlarging the beam diameter of the light beam from the light source and giving it to the reflecting means; and a relative relationship between the first lens group and the second lens group of the beam diameter converting optical system. It is characterized in that it is provided with adjusting means for adjusting the position so as to change the beam waist position of the projection beam.

According to the above construction, it is possible to obtain the beam projection apparatus which can easily perform the focusing for adjusting the beam waist position, and the optical system relating to the focusing is reflected between the first and second lens groups. There are no members,
It is possible to construct a straight and small optical system in which the relative positions of both lens groups can be changed within the same optical path.

Further, when the second lens group is fixed to the optical path between the collimating lens and the reflecting means and the first lens group is provided so as to be able to advance and retreat with respect to the second lens group, for example, the first lens group becomes the second lens. It is possible to reduce the load of the drive system for moving the group back and forth.

[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 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 extending in the vertical direction, and a rotary light projecting portion 15 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 beam and a collimator lens 24 that converts the beam from the semiconductor laser 23 into a parallel beam having an elliptical cross section are provided in the laser beam optical path 20a. Although the collimator lens 24 is illustrated as if it is composed of one lens for convenience,
Actually, it is composed of a plurality of lenses (see FIG. 4).

A polarization beam splitter 27 for receiving 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 projection 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. An increased reflection film is formed on the second reflection surface 35b 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 its hypotenuse affixed to the first reflecting surface 35a, and the exit surface 34a located in the upper part of FIG. 1 is parallel to the light incident surface 35c of the pentaprism 35.

The hollow member 20 integrally has a drive arm 37 extending rightward in FIG. 1 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 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 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 31 having negative power and a second lens group 32 having positive power are provided. The second lens group 32 is fixed to the pentaprism 35 side of the laser light optical path 20b. The first lens group 31 is supported by a cylindrical member 30 that can move forward and backward in the optical axis direction within the optical path 20b, and is configured to move forward and backward with respect to the second lens group 32. A beam expander (beam diameter conversion optical system) B is configured by the first and second lens groups 31 and 32.

A bracket 53 is provided at the lower part of the hollow member 20 so as to project outward.
The bracket 5 facing the bracket 53 is provided on the upper part of the
5 is formed. Gear support holes 53a and 55a facing each other are formed in the brackets 53 and 55, and shaft portions at both ends of the lens moving screw 56 are rotatably fitted in the gear support holes 53a and 55a. Further, the pinion 60 fixed to the rotation shaft of the lens moving motor 59 fixed to the bracket 53 is
6 meshes with a transmission gear 61 fixed to the lower end portion of 6.
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 30, and the insertion window 63 has
Links 62 having both ends fixed to the cylindrical member 30 and the lens moving nut 57 respectively pass therethrough.

Next, the general operation of the laser surveying instrument 11 will be described. 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. Drive switch (not shown) in this state
When is turned on, the microcomputer 82 rotationally drives the first and second level adjusting motors 44 and 75, respectively, based on the calculated angle deviation. For example, when the adjusting 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 urged by the tension spring 52 is elastically contacted with the operation pin 47 of the nut 46, the hollow member 20 is moved by the roller 4.
The rotary light projecting unit 15 is tilted with respect to the vertical direction by being rotated about the spherical center of the bulging portion 21 via 0. When the adjusting motor 75 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, since the roller 41 urged by the tension spring 52 is elastically contacted with the operation pin 81 of the nut 80, the rotary light projecting portion 15 is tilted with respect to the vertical direction in the same manner as above.

When the light projecting device 13 is tilted and the leveling is advanced, 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.

When the leveling work is completed, the microcomputer 8
When a driving signal is output from the semiconductor laser 23 and the semiconductor laser 23 starts to oscillate, 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 polarization beam splitter 27. It is divided 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 entering 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 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 axial direction is 45 ° with respect to the vibration direction of the light, the laser beam L ₀ passes through the 1/4 λ plate 28 and is circled. Polarized laser beam L
It becomes ₁ and goes to the pentaprism 35. Further, the laser light flux L ₁ reflected by the semi-transparent film 28a is again transmitted through the 1/4 λ plate 28, and then converted into a linearly polarized light of a P-polarized component having a vibration in a direction orthogonal to the time of incidence, and a polarization separation surface. 27a
Transmitted towards the figure below as the laser beam L ₂ a, wedge prism 29a, passes through the 29 b, is injected into the lower outer side.

On the other hand, the upwardly directed laser beam L ₁ passes through the first and second lens groups 31 and 32, the light incident surface 35c of the pentaprism 35, and then the first and second reflecting surfaces 35a, 35a. The light is sequentially reflected by 35b, deflected by 90 ° in the course, and emitted from the light emitting surface 35d in a substantially horizontal direction. Except for the laser beam L ₁ reflected by the first reflection surface 35a at a predetermined ratio, it passes through the half mirror surface formed by the first reflection surface 35a and the wedge-shaped prism 34 without changing the course. The laser beam L ₄ coaxial with the laser beam L ₁ is projected upward. 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. Laser beam L ₃ emitted to
Forms a horizontal reference plane.

By the way, the laser light beam L ₃ emitted from the rotary light projecting portion 15 spreads due to diffraction even if it is emitted as a parallel light beam, and is not a parallel light beam. Therefore, in a system that projects a laser beam to a distant place like a laser planar,
A means for projecting a thick laser beam in response to a request for the reaching distance and for enabling the beam waist to be at an appropriate position by the weak convergent light is required.

At that time, for example, the lenses (the first and second lens groups 31, 32, etc.) are changed by the wavelength change of the semiconductor laser 23.
If the beam waist position deviates from the prescribed position due to changes in the power of, or if accurate measurement at a short distance is required, adjust the beam waist position (focus), or This adjustment requires making the spot as small as possible.

Conventionally, there was a laser surveying instrument having a focusing function (see Japanese Patent Laid-Open No. 5-322564). However, this laser surveying instrument has a structure in which a prism is located in the optical path of a laser beam from a semiconductor laser. Since it is difficult to match the optical axes of the condenser lens and the objective lens that moves by focusing, the optical system for focusing is large.

The laser surveying instrument 11 has a structure in which focusing can be performed easily, eccentricity at the time of focusing is small, and an optical system relating to focusing can be made as small as possible.

That is, the laser surveying instrument 11 drives the lens moving motor 59 based on a signal from the microcomputer 82 to move the cylindrical member 30 up and down via the feed screw mechanism, and the first lens group 31 to the second lens. By moving the group 32 back and forth, the distance (relative position) between them can be changed. As a result, the laser light flux from the semiconductor laser 23, which has been converted into a parallel light flux via the collimator lens 24, has its beam diameter enlarged and is given to the pentaprism 35, and the laser light flux L projected outward from the rotary light projecting unit 15. The beam waist position of ₃ can be easily moved and adjusted to be optimum or desired at a required distance. Therefore, the use condition of the laser surveying device 11 in the field or the like can be always improved.

The beam expander B composed of the first lens group 31 and the second lens group 32 is a straight optical system which can change the distance between the lens groups 31 and 32 in the same optical path without interposing a reflecting member. Since it is configured as, there is little eccentricity during focusing (it is less likely to fall during focusing). Further, this structure also has an effect that there is little adverse effect due to the decentering of the lens during assembly.
Further, the second lens group 32 fixed to the pentaprism 35 side of the laser light optical path has a positive power, and the first lens group 31 located on the collimating lens 24 side has a negative power. The diameter of the group 31 can be made smaller than the beam diameter of the emitted light beam. Therefore, this first lens group 31
Since the load of the lens moving motor 59 for advancing and retracting is small, a motor having a small output can be used as the motor 59.

Specific examples of the collimator lens 24 and the beam expander B that can be used in the laser surveying instrument 11 will now be described.

FIG. 4 shows an example of the lens structure of the collimator lens 24. This collimating lens 24 has lenses 101, 102, 103 and 104, and has a focal length of 6 mm.
It has been. The lenses 101 and 102 are cemented (bonded) lenses. Reference numeral 105 in the figure denotes a cover glass of the semiconductor laser 23, and r _{1 to} r ₉ denote the radius of curvature of each surface of the cover glass or the lens, and d _{1 to} d
₈ indicates the thickness of the cover glass, the lens thickness or the lens interval.

Table 1 shows specific numerical data of the collimator lens 24. In the table, Ri is i-th from the light source side in the figure.
The radius of curvature of the th surface, Di is the thickness of the ith cover glass or lens from the light source side, or the lens interval, and n is
The refractive index at 635 nm of the lens, ν, indicates the Abbe number of the d line of the lens.

[0038]

[Table 1] Face No. Ri Di n ν 1 ∞ 0.30 1.51455 64.1 2 ∞ 2.73 3 -4.624 1.80 1.72623 54.7 4 -3.519 0.10 5 -75.123 1.80 1.69065 53.2 6 -7.118 4.38 7 -105.190 1.60 1.83928 23.9 8.48.42 2.25 1.61586 63.4 9 -13.310-

FIG. 5 shows a first example of the lens structure of the beam expander B. This beam expander B is composed of a first lens group 31 and a second lens group 32, one by one,
The beam expansion rate has been determined to be 1.3 times.

Table 2 shows specific numerical data of this beam expander B, and various aberrations such as longitudinal aberration, lateral aberration and wavefront aberration are shown in FIGS. 6 to 8. These various aberrations are shown in FIG.
In Fig. 3, the aberration is on the image plane when light is incident from the left side of the figure. In the various aberration diagrams, ER is the entrance pupil height, B is the entrance angle, S is the sagittal direction, and M is the meridional direction. In the table, Ri is the radius of curvature of the i-th surface from the left side of FIG. 5, Di is the wall thickness or lens interval of the i-th lens from the light source side, n is the refractive index of the lens at 635 nm, and ν is , And the Abbe number of the d line of the lens.

[0041]

[Table 2] Surface No. Ri Di n ν 1 -59.000 2.50 1.60003 38.0 2 237.849 23.09 3 ∞ 3.50 1.69065 53.2 4 -72.480-

FIG. 9 shows a second example of the first lens group 31 in the first example of the beam expander B shown in FIGS.
It shows a change in the radius of curvature (geometrically determined) of the wavefront of the projected laser light flux when it is moved in a direction away from the lens group 32. From the change curve in the figure, it can be seen that the beam expander B has a large change amount of the radius of curvature when the first lens group 31 is moved, and has high movement sensitivity. From this, the beam expander B can adjust the beam waist position according to the request by only slightly moving the first lens group 31, which is a focusing lens, and in terms of downsizing of the optical system and the like. It can be understood that it is effective.

In this embodiment, the second lens group 32 is fixed and the first lens group 31 can move forward and backward with respect to the second lens group 32, but the present invention is not limited to this.
That is, the first lens group 31 can be fixed in the laser beam optical path 20b, and the second lens group 32 can be supported so as to be movable back and forth with respect to the first lens group 31. In this case, a cylindrical member (not shown) similar to that of the above embodiment is slidably provided in the laser beam optical path 20b, and the second lens group 32 is supported by this cylindrical member. Even with such a configuration, the second lens group 32 is not
The change curve when moved in the direction away from is exactly the same as in FIG.

FIG. 10 shows a second example of the lens structure of the beam expander B. This beam expander B has 1
The first lens group 31 and the second lens group 32 are provided one by one, and the beam expansion rate is determined to be 1.80. Table 3 shows specific numerical data of the beam expander B, and FIGS. 11 to 13 show various aberrations such as longitudinal aberration, lateral aberration, and wavefront aberration. Similar to the first example, these various aberrations are aberrations on the image plane when light is incident from the left side of FIG.

[0045]

[Table 3] Surface No. Ri Di n ν 1 -226.334 2.50 1.83925 23.8 2 41.595 30.86 3 302.150 3.80 1.49566 81.6 4 -42.213-

FIG. 14 shows a third example of the lens structure of the beam expander B. Table 4 shows specific numerical data of the beam diameter conversion optical system B, and FIGS. 15 to 17 show various aberrations such as longitudinal aberration, lateral aberration, and wavefront aberration. The beam expansion rate of the beam diameter conversion optical system B is determined to be 2.07 times.

[0047]

[Table 4] Surface No. Ri Di n ν 1 166.594 2.50 1.83925 23.8 2 25.516 36.37 3 -1170.933 3.80 1.45488 90.3 4 -33.184-

In the third example of the beam expander B, the lens weight of the first lens group 31 is 0.37 g, and the lens weight of the second lens group 32 is 2.83 g. Therefore, the relatively heavy second lens group 32 is fixed in the optical path of the laser beam, and the first lens group 31 lighter than the second lens group 32 is provided.
It can be understood how effective the configuration of the laser surveying device 11 for advancing and retreating is to reduce the load on the drive system.

FIG. 18 shows a fourth example of the lens structure of the beam expander B. Table 5 shows specific numerical data of the collimator lens 24, and FIGS. 19 to 21 show various aberrations such as longitudinal aberration, lateral aberration and wavefront aberration. The beam expansion rate of this beam expander B is determined to be 1.70 times.

[0050]

[Table 5] Surface No. Ri Di n ν 1 88.796 2.50 1.79857 25.4 2 29.160 39.79 3 -122.664 3.80 1.45488 90.3 4 -32.265-

FIG. 22 shows a fifth example of the lens structure of the beam expander B. Table 6 shows specific numerical data of the beam diameter conversion optical system B, and FIGS. 23 to 25 show various aberrations such as longitudinal aberration, lateral aberration, and wavefront aberration. The beam expansion ratio of the beam diameter conversion optical system B is determined to be 1.33 times.

[0052]

[Table 6] Surface No. Ri Di n ν 1 -68.751 2.50 1.55463 58.7 2 121.059 23.37 3 330.562 3.50 1.57838 40.7 4 -74.023-

[0053]

As described above, according to the present invention, it is possible to obtain a beam projection apparatus which can easily perform focusing for adjusting the beam waist position and can be fully utilized outdoors. Moreover, the focusing optical system can be configured as a straight and small optical system that does not have a reflecting member between the lens groups and can change the relative positions of both lens groups within the same optical path.

According to the second aspect of the present invention, when the first lens group is moved back and forth with respect to the second lens group, the load on the drive system can be reduced.

[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 an example of a collimator lens that can be used in the laser surveying instrument.

FIG. 5 is a lens configuration diagram showing a first example of a beam expander.

FIG. 6 is a longitudinal aberration diagram of the beam expander.

FIG. 7 is a lateral aberration diagram of the beam expander.

FIG. 8 is a wavefront aberration diagram of the same beam expander.

FIG. 9 is a diagram showing the correlation between the amount of movement of the first lens group of the same beam expander and the radius of curvature of the wavefront of the emitted laser beam.

FIG. 10 is a lens configuration diagram showing a second example of a beam expander.

FIG. 11 is a longitudinal aberration diagram of the same beam expander.

FIG. 12 is a lateral aberration diagram of the same beam expander.

FIG. 13 is a wavefront aberration diagram of the same beam expander.

FIG. 14 is a lens configuration diagram showing a third example of a beam expander.

FIG. 15 is a longitudinal aberration diagram of the beam expander.

FIG. 16 is a lateral aberration diagram of the beam expander.

FIG. 17 is a wavefront aberration diagram of the same beam expander.

FIG. 18 is a lens configuration diagram showing a fourth example of a beam expander.

FIG. 19 is a longitudinal aberration diagram for the beam expander.

FIG. 20 is a lateral aberration diagram of the same beam expander.

FIG. 21 is a wavefront aberration diagram of the same beam expander.

FIG. 22 is a lens configuration diagram showing a fifth example of a beam expander.

FIG. 23 is a longitudinal aberration diagram for the beam expander.

FIG. 24 is a lateral aberration diagram for the beam expander.

FIG. 25 is a wavefront aberration diagram of the same beam expander.

[Explanation of symbols]

 11 Laser Surveying Device (Beam Projecting Device) 15 Rotating Light Emitting Unit (Light Emitting Unit) 20 Hollow Member 20a 20b Laser Light Optical Path 23 Semiconductor Laser (Light Source) 24 Collimating Lens 30 Cylindrical Member (Lens Support Member, Adjusting Means) 31 First Lens group 32 Second lens group 35 Penta prism (reflecting means) 56 Lens moving screw (adjusting means) 57 Lens moving nut (adjusting means) 59 Lens moving motor (adjusting means) 60 Pinion 61 Transmission gear 62 Link (adjusting means) 63 Insertion window 101 102 103 104 Lens B Beam expander (beam diameter conversion optical system) a Rotation axis

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[Procedure amendment]

[Submission date] August 24, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

FIG. 4 shows an example of the lens structure of the collimator lens 24. This collimating lens 24 is a lens
102 , 103 , 104 , 105 with a focal length of 6 mm
It has been. The cover glass 101 is a semiconductor laser.
It is attached to The 23. Lenses 104 and 10
5 is a cemented (bonded) lens. <br/> sign-r ₁ ~r ₉ in the figure indicates the radius of curvature of the cover glass or lens surfaces, d ₁ to d ₈ is the thickness of the cover glass shows lens Atsuwaka Shikuwa lens distance.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of Codes] 11 Laser Surveying Device (Beam Projector) 15 Rotating Light Emitting Unit (Light Emitting Unit) 20 Hollow Member 20a 20b Laser Light Optical Path 23 Semiconductor Laser (Light Source) 24 Collimating Lens 30 Cylindrical Member (Lens Support Member, Adjustment) 31) First lens group 32 Second lens group 35 Penta prism (reflecting means) 56 Lens moving screw (adjusting means) 57 Lens moving nut (adjusting means) 59 Lens moving motor (adjusting means) 60 Pinion 61 Transmission gear 62 Link (Adjusting means) 63 insertion window 102 103 104 105 lens B beam expander (beam diameter conversion optical system) a rotating shaft

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

Claims (4)

[Claims] 1. A reflecting means reflects a light beam from a light source,
A beam projecting device for projecting a light beam as a substantially parallel light beam, the collimator lens converting a light beam from the light source into a substantially parallel light beam; a negative lens located on the collimator lens side in an optical path between the collimator lens and the reflecting means. Beam diameter conversion optics for expanding the beam diameter of the light beam from the light source and giving it to the reflecting means. System; and adjusting means for adjusting the relative position of the first lens group and the second lens group of the beam diameter conversion optical system so as to change the beam waist position of the projection beam. Beam projection device. 2. The first lens group according to claim 1, wherein the second lens group is fixed to an optical path between the collimating lens and the reflecting means,
The beam projecting device, wherein the lens group is supported by a lens supporting member which is provided in the optical path so as to be movable back and forth with respect to the second lens group and which is a part of the adjusting means. 3. The first lens group according to claim 1, being fixed to an optical path between the collimating lens and the reflecting means,
The beam projecting device, wherein the lens group is supported by a lens support member which is provided in the optical path so as to be movable back and forth with respect to the first lens group and which is a part of the adjusting means. 4. The method according to claim 1, wherein
The reflecting means is provided in a light projecting section rotatable about a rotation axis, and the beam from the reflecting means is rotationally projected in a direction substantially orthogonal to the rotation axis by the rotation of the light projecting section to project a reference plane. A beam projection device characterized by being formed.