A laser and plummet detection system calibration device and calibration method thereof

Abstract

The application discloses a kind of lasers, including light source generating device, first shaping device and second shaping device, the light source generating device is used to generate the initial laser with the initial light spot of circular, the first shaping device includes first double-concave lens and first plano-convex lens, for the light spot preliminary shaping, expansion and reduce divergence angle, the second shaping device includes second double-concave lens and second plano-convex lens, for expansion by fixed multiple, reduce divergence angle to close to zero, emit approximately parallel laser;The application also discloses a plumb instrument detection system calibration device comprising the laser and a calibration method thereof.The laser of the application can generate laser with the same two-direction divergence angle of circular light spot, suitable for plumb instrument detection system calibration device, rotation will not affect calibration result due to light spot asymmetry, improve calibration accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser and calibration detection technology, in particular to a laser and plumb detection system calibration device and a calibration method thereof. BACKGROUND

[0002] At present, most of the 635nm-660nm waveband red laser used is basically a semiconductor laser, that is, an LD laser diode directly emits light, and the light spot mode is not a strict TEM00 mode. The light spot mode is not good, not a Gaussian distribution, and the divergence angles in two directions are different, so that the light spot is elliptical. Therefore, when the red laser is used to calibrate the plumb calibration device, the rotation directly affects the calibration result due to the asymmetry of the elliptical light spot, resulting in inaccurate calibration result. SUMMARY

[0003] (I) Technical problem to be solved

[0004] Based on the above problems, the present application provides a laser and plumb detection system calibration device and a calibration method thereof, so that the laser can generate laser with circular light spot and same divergence angle in two directions, which is suitable for plumb detection system calibration device, and solves the problem that the rotation of the laser does not affect the calibration result due to the asymmetry of the light spot.

[0005] (II) Technical scheme

[0006] Based on the above technical problems, the present application provides a laser, which comprises a light source generating device, a first shaping device and a second shaping device. The light source generating device is used to generate initial laser with circular initial light spot in TEM00 mode. The first shaping device comprises a first double-concave lens and a first plano-convex lens, which are used to preliminarily shape the light spot, expand the beam and reduce the divergence angle. The second shaping device comprises a second double-concave lens and a second plano-convex lens, which are used to expand the beam by a fixed multiple, reduce the divergence angle to near zero, and emit approximately parallel laser. The curvatures of the first double-concave lens, the first plano-convex lens, the second double-concave lens and the second plano-convex lens, the distance between the first double-concave lens and the first plano-convex lens, and the distance between the second double-concave lens and the second plano-convex lens are selected or set according to the adjustment multiple of the laser. The expansion size and the divergence angle of the laser emitted by the laser are set according to the requirements of the laser receiving end for the expansion size and the divergence angle and the distance of the laser receiving end.

[0007] Further, a filter is arranged between the first double-concave lens and the first plano-convex lens, which is used for filtering the light source.

[0008] Further, the light source generating device comprises a pump source, a gain working medium and a frequency doubling crystal.

[0009] Further, the pump source is a semiconductor laser diode (LD), the gain working medium is a neodymium-doped yttrium vanadate (Nd:YVO4), and the frequency doubling crystal is a potassium titanyl phosphate (KTP) crystal.

[0010] Further, the beam expansion multiple of the second plano-convex lens is determined according to the following formula:

[0011] The beam expansion multiple M is equal to the focal length f1 of the exit pupil lens divided by the focal length f2 of the entrance pupil lens.

[0012] The application also discloses a plumb instrument detection system calibration device comprising the laser, which comprises a lifting table, a moving platform, a ridge prism, a standard laser, a laser receiving screen, a moving platform displacement processing display device and a receiving screen data processing display device.

[0013] Further, the moving platform comprises a base, a guide rail, a lead screw, a workbench, a limiting device, a speed regulating motor and a grating.

[0014] Further, the distance between the laser receiving screen and the ridge prism is at least 100 m.

[0015] The application also discloses a calibration method of the plumb instrument detection system calibration device.

[0016] S1, installing the plumb instrument detection system calibration device;

[0017] S2, selecting an initial position on the moving platform, selecting q points in the full range, q >= 5, and controlling the workbench on the moving platform to move in a direction to give a standard value L of the movement of the standard laser driven by the workbench. i0 That is, reading the reading of the moving platform displacement processing display device and the indication L of the plumb instrument detection system. i, namely, receiving the reading corresponding to the screen data processing display device, i = 1, 2,..., q;

[0018] S3, calculating the indication error of each measuring point by the following formula:

[0019] △ i = L i - L i0 ;

[0020] S4, horizontally rotating the motion platform to be 60° and 120° with the initial position respectively, repeating the arrangement of S2 and S3;

[0021] S5, taking the maximum absolute value of the 3xq indication error measurement results as the final result.

[0022] Further, each measuring point should be measured p times, and the plumb instrument detection system indication L i should be the average value of p readings, p >= 3.

[0023] (Three) beneficial effects

[0024] The above technical scheme of the present application has the following advantages:

[0025] (1) The light source generating device of the present application generates an initial laser with a circular initial light spot in TEM00 mode, and then preliminarily shapes, expands and narrows the divergence angle through a first double-concave lens and a first plano-convex lens, and then expands and narrows the divergence angle to approximately zero through a second double-concave lens and a second plano-convex lens, so that the laser can generate a laser with a circular light spot and the same divergence angle in two directions and approximately zero, and the human eye is more sensitive to the 532nm green laser;

[0026] (2) The present application uses the laser as a standard laser for the plumb instrument detection system calibration device, and since the standard laser spot is symmetrical, the rotation of the standard laser does not affect the calibration result, thereby facilitating the improvement of the calibration accuracy of the plumb instrument detection system calibration device;

[0027] (3) The plumb instrument detection system calibration device of the present application utilizes the reflection characteristics of the ridge prism, moves the standard laser through the workbench, and rotates the standard laser horizontally through the motion platform, which meets the working conditions of the plumb instrument, and can be used for the calibration of the plumb instrument detection system, and the standard laser does not affect the calibration result with horizontal rotation;

[0028] (4) The calibration method of the present application takes the movement distance of the standard laser as the standard quantity, measures the error of multiple measuring points through the detection quantity of the laser receiving screen, and measures the error at different rotation angles, which meets the working conditions of the plumb instrument, and the application of the calibration device combined with the calibration method can effectively calibrate the plumb instrument detection system. BRIEF DESCRIPTION OF DRAWINGS

[0029] The features and advantages of the present application will be appreciated upon reference to the following detailed description and drawings in which:

[0030] Figure 1 A schematic diagram of a light source generating device and a first shaping device of an embodiment of the laser;

[0031] Figure 2 A schematic diagram of a first shaping device and a second shaping device of an embodiment of the laser;

[0032] Figure 3 A power density diagram of a minimum position and a maximum position of a circular light spot generated by an embodiment of the laser;

[0033] Figure 4 A schematic diagram of a circular light spot generated by an embodiment of the laser;

[0034] Figure 5 A schematic diagram of an elliptical light spot of the background art;

[0035] Figure 6 A schematic diagram of a plumb detection system calibration device of an embodiment of the application;

[0036] Figure 7 A schematic diagram of the structure of a motion platform of an embodiment of the application;

[0037] In the figure: 1: pump source; 2: gain working medium; 3: frequency doubling crystal; 41: first biconcave lens; 51: first plano-convex lens; 42: second biconcave lens; 52: second plano-convex lens; 6: optical filter; 7: lifting platform; 8: motion platform; 9: roof prism; 10: standard laser; 11: laser receiving screen; 12: motion platform displacement processing display device; 13: receiving screen data processing display device; 81: base; 82: guide rail; 83: lead screw; 84: workbench; 85: speed regulating motor; 86: grating. DETAILED DESCRIPTION

[0038] The specific embodiments of the application will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the application, but are not used to limit the scope of the application.

[0039] An embodiment of the application is a 532nm green laser for a plumb detection system calibration device, which comprises a light source generating device, a first shaping device and a second shaping device; the light source generating device, as shown in Figure 1 includes a pump source 1, a gain working medium 2 and a frequency doubling crystal 3, the first shaping device, as shown in Figure 1 andFigure 2 As shown, it includes a first biconcave lens 41 and a first plano-convex lens 51, and the second shaping device is as follows: Figure 2 As shown, it includes a second biconcave lens 42 and a second plano-convex lens 52;

[0040] Among them, pump source 1 is a semiconductor laser diode LD, gain working medium 2 is neodymium yttrium vanadate Nd:YVO4, frequency doubling crystal 3 is potassium titanate oxyphosphate crystal, i.e. KTP crystal. Red light with a wavelength of 808nm is obtained through LD, red light with a wavelength of 1064nm is obtained through Nd:YVO4, and green light with a wavelength of 532nm is obtained through KTP. The human eye is very sensitive to green light with a wavelength of 532nm. At this time, the initial spot of the initial laser is a circular green spot, but the divergence angle is large.

[0041] The working principle of initial spot processing is as follows: Figure 2 As shown, the light spot is initially shaped by the first biconcave lens 41 and the first plano-convex lens 51, i.e., the beam is expanded and the divergence angle is reduced. Then, the light spot is further shaped by the second biconcave lens 42 and the second plano-convex lens 52, expanding the beam by a fixed factor and reducing the divergence angle to approximately zero, so that the second plano-convex lens 52 emits approximately parallel green light. Since the laser emitted by a set of biconcave and plano-convex lenses cannot expand the beam and reduce the divergence angle to meet the standard for lasers used in the calibration device of the plumb line detection system, a second set of biconcave and plano-convex lenses is used to further expand the beam and reduce the divergence angle, and the first biconcave lens 41... A filter 6 is installed between the first biconcave lens 41 and the first plano-convex lens 51 to filter out any possible red light. The curvature of each biconcave lens and plano-convex lens, the distance between the first biconcave lens 41 and the first plano-convex lens 51, and the distance between the second biconcave lens 42 and the second plano-convex lens 52 are all selected or set according to the adjustment magnification of the laser. The beam expansion and divergence angle of the laser emitted by the laser are set according to the requirements of the laser receiver for the beam expansion and divergence angle and the distance of the laser receiver. The adjustment magnification of each biconcave lens and plano-convex lens uses the basic beam expansion formula of thin lenses.

[0042] The beam expansion factor M = focal length of the exit pupil lens f1 / focal length of the entrance pupil lens f2

[0043] Then, in conjunction with the corresponding design wavelength and lens material requirements, simulation results and tolerance analysis results are provided through design software, thereby ensuring the feasibility of the system and the reliability of actual assembly. This 532nm green laser is a semiconductor-pumped solid-state laser, generating laser light in strict TEM00 mode with good spot pattern, such as... Figure 3 As shown, the minimum and maximum positions of the circular light spot both exhibit a Gaussian distribution, with the same divergence angle in both directions, resulting in a circular light spot. Figure 4 As shown, the light spot in the background technology Figure 5 As shown.

[0044] The calibration device of the plumb instrument detection system is shown in Figure 6 The calibration device of the plumb instrument detection system is shown in The calibration device of the plumb instrument detection system is shown in

[0045] The calibration device of the plumb instrument detection system is shown in Figure 7 The calibration device of the plumb instrument detection system is shown in The calibration device of the plumb instrument detection system is shown in

[0046] The calibration device of the plumb instrument detection system is shown in The calibration device of the plumb instrument detection system is shown in

[0047] S1, install the calibration device as described above;

[0048] S2, arbitrarily select a position on the motion platform 8 as the initial position, evenly select 5 points in the full range, control the workbench 84 on the motion platform 8 to move linearly in one direction, and give the standard value L i0 , that is, read the reading of the motion platform displacement processing display device 12, and read the indication value L iThe reading corresponding to the receiving screen data processing display device 13 is received, and the whole process is repeated for three times, and the average value of three readings of each measuring point is taken as the detection result L of the point i ;

[0049] S3, the indication error of the point is calculated by the following formula:

[0050] △ i =L i -L i0

[0051] L i - the average value of three readings of the plumb detection system at the point, i = 1, 2,..., 5;

[0052] L i0 - the standard value given by the workbench at the point;

[0053] When the workbench 84 drives the laser to move L0, the position of the laser center point on the laser receiving screen 11 should also be displaced by L0, and at this time the indication value of the plumb detection system will change L, and by calculating the difference between L and L0, the indication error of the plumb detection system can be obtained;

[0054] S4, the horizontal rotating motion platform 8 is arranged at an angle of 60° and 120° with the initial position respectively, and S2 and S3 are repeated;

[0055] Since uniform rotation is required during the plumb detection process, the eccentricity geometric center is taken as the reference point, therefore, the calibration device of the plumb detection system should also be used to obtain the indication error at least at 0°, 60° and 120°. The 532nm green laser of the present application is a semiconductor-pumped solid laser, and the generated laser is a strict TEM00 mode, the spot mode is good, and it is a Gaussian distribution, the divergence angles of two directions are the same, the spot is circular, and the influence of the asymmetry of the spot itself on the calibration result is very small when rotating, which greatly improves the accuracy of the calibration device.

[0056] S5, taking the maximum absolute value of 15 indication error measurement results as the final result.

[0057] As can be seen from the above, the laser and plumb detection system calibration device and the calibration method thereof have the following beneficial effects:

[0058] (1) the light source generating device of the present application generates the initial laser with TEM00 mode and the initial light spot with circular shape, then the initial laser is preliminarily shaped, expanded and the divergence angle is reduced by the first double-concave lens and the first plano-convex lens, and then the laser is expanded and the divergence angle is reduced to approximately zero by the second double-concave lens and the second plano-convex lens, so that the laser with the circular light spot and the same and approximately zero divergence angle in two directions can be generated, and the human eye is more sensitive to the 532nm green laser;

[0059] (2) the laser is used as the standard laser in the plumb detection system calibration device, and the rotation of the standard laser does not affect the calibration result due to the spot symmetry of the standard laser, so that the calibration accuracy of the plumb detection system calibration device is improved;

[0060] (3) the plumb detection system calibration device utilizes the reflection characteristics of the roof prism, moves the standard laser by the workbench, rotates the standard laser horizontally by the motion platform, and is suitable for the working condition of the plumb, so that the plumb detection system can be calibrated, and the standard laser does not affect the calibration result with the horizontal rotation;

[0061] (4) the calibration method takes the moving distance of the standard laser as the standard quantity, measures the error of multiple measuring points by the detection quantity of the laser receiving screen, and measures the error of different rotation angles, so that the working condition of the plumb is met, and the plumb detection system can be effectively calibrated by the calibration device combined with the calibration method.

[0062] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the embodiments of the present application are described in combination with the drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A calibration method for a calibration device of a plumb line testing system, characterized in that, Includes the following steps: S1. Install the calibration device of the plumb line detection system; S2. Arbitrarily select a position on the motion platform as the initial position. Uniformly select q points (q≥5) across the entire range. Control the worktable on the motion platform to move in one direction. Provide the standard value L for the worktable to move the standard laser. i0 That is, reading the displacement processing display device of the motion platform and reading the value L indicated by the plumb bob detection system. i , that is, the reading corresponding to the receiving screen data processing and display device, i = 1, 2, ..., q; S3. Calculate the indication error of each measurement point using the following formula: △ i =L i -L i0 ; S4. Horizontally rotate the motion platform to make angles of 60° and 120° with the initial position, and repeat steps S2 and S3. S5. Take the largest absolute value among the 3×q indication error measurement results as the final result; The calibration device for the plumb line detection system includes: a plumb line detection system, a motion platform, a standard laser, and a motion platform displacement processing and display device. The plumb line detection system includes a lifting platform, a ridge prism, a laser receiving screen, and a receiving screen data processing and display device. The motion platform is rotatably mounted on the lifting platform. The motion platform has a movable worktable. A standard laser is fixed vertically upward on the worktable. The standard laser is the laser itself. The ridge prism is located above the motion platform and is angled at 45 degrees to the horizontal plane towards the laser receiving screen, which is perpendicular to the ground. This allows the laser beam to be emitted vertically upward from the standard laser, pass through the ridge prism, and then be directed horizontally towards the laser receiving screen. The motion platform displacement processing and display device is connected to the motion platform and is used to calculate and display the displacement of the worktable on the motion platform. The receiving screen data processing and display device is connected to the laser receiving screen and is used to calculate and display the displacement of the received laser beam. The laser includes a light source generating device, a first shaping device, and a second shaping device. The light source generating device generates an initial laser beam with a circular initial spot in TEM00 mode. The first shaping device includes a first biconcave lens and a first plano-convex lens for initial shaping of the spot, expanding the beam and reducing the divergence angle. The second shaping device includes a second biconcave lens and a second plano-convex lens for expanding the beam by a fixed factor and reducing the divergence angle to near zero, emitting an approximately parallel laser beam. The curvature of the first biconcave lens, the first plano-convex lens, the second biconcave lens, and the second plano-convex lens, the distance between the first biconcave lens and the first plano-convex lens, and the distance between the second biconcave lens and the second plano-convex lens are all selected or set according to the adjustment factor of the laser. The beam expansion size and divergence angle of the laser beam emitted by the laser are set according to the requirements of the laser receiver for the beam expansion size and divergence angle and the distance of the laser receiver. The adjustment factor of each biconcave lens and plano-convex lens uses the basic beam expansion formula of thin lenses. The beam expansion factor M = focal length of the exit pupil lens f1 / focal length of the entrance pupil lens f2 Then, in conjunction with the corresponding design wavelength and lens material requirements, simulation results and tolerance analysis results are provided through design software.

2. The calibration method for a calibration device of a plumb line detection system according to claim 1, characterized in that, A filter is installed between the first biconcave lens and the first plano-convex lens for filtering the light source.

3. The calibration method for a calibration device for a plumb line detection system according to claim 1, characterized in that, The light source generating device includes a pump source, a gain working medium, and a frequency doubling crystal.

4. The calibration method for a calibration device for a plumb line detection system according to claim 3, characterized in that, The pump source is a semiconductor laser diode (LD), the gain working medium is neodymium-doped yttrium vanadate (Nd:YVO4), and the frequency doubling crystal is potassium titanium oxyphosphate crystal, i.e., KTP crystal.

5. The calibration method for a calibration device for a plumb line detection system according to claim 1, characterized in that, The motion platform includes a base, guide rail, lead screw, worktable, limiting device, speed-regulating motor, and grating. The worktable is mounted on the guide rail via the lead screw, which is connected to the speed-regulating motor, which is manually adjustable. The speed-regulating motor drives the worktable to slide linearly on the guide rail. The limiting device is located at both ends of the guide rail. The grating is located on the side of the worktable and moves with the worktable, used for displacement measurement of the worktable.

6. The calibration method for a calibration device for a plumb line detection system according to claim 1, characterized in that, The distance between the laser receiving screen and the roof prism is at least 100m.

7. The calibration method for a calibration device for a plumb line detection system according to claim 1, characterized in that, Each measurement point should be measured p times, and the reading L of the plumb line detection system should be... i It should be the average of p readings, where p ≥ 3.

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