Polarization-adjustable variable-magnification laser beam expansion collimator with adjustment warning and collimation method thereof

Abstract

The present invention discloses a variable-magnification laser beam expander collimator with adjustable polarization and an adjustment warning and a collimation method thereof. The collimator comprises a polarization adjustment device, a beam expander device, a compensation collimator device and a warning device arranged on a collimator barrel. The polarization adjustment device comprises a rotatable and adjustable polarization prism and a polarization wave plate arranged in sequence in the collimator barrel; the beam expander device comprises a beam expander lens connected to a polarization wave plate on one side of the collimator barrel, and a fine adjustment parallel spiral and a coarse adjustment parallel spiral sequentially sleeved on the outside of the beam expander lens; the compensation collimator device comprises a supplementary collimator barrel and a collimator lens; the warning device comprises a coated photocell coating layer, an electric conversion light warning lamp and a photoelectric conversion circuit. The present invention continuously and adjustable expands and collimates the incident laser beam, and can eliminate polarization state changes. At the same time, the power ratio of the outgoing light to the incident light is greater than 80%, which fully utilizes the incident light, and has a simple structure, simple manufacturing and low cost.

Description

Technical Field

[0001] The invention relates to the technical field of optical instruments, and in particular to a polarization-adjustable variable-power laser beam expansion collimator with an adjustment warning and a collimation method thereof. Background Art

[0002] Lasers are widely used due to their high brightness, monochromaticity and directionality. The beam diameter emitted by ordinary lasers is generally 1~10mm and is prone to fluctuations in laser power and changes in the polarization state of the output beam. In most existing polarization-maintaining fiber input beam expansion and collimation systems, only the wave plate can be rotated to change the polarization angle of the input laser, and the polarization state cannot be accurately adjusted. In actual work, a parallel beam with a large beam diameter and stable polarization state that can be accurately adjusted is often required, so it is necessary to adjust the polarization state and expand and collimate the laser. Beam expansion collimators have a wide range of uses in optical engineering. At present, most common laser beam expansion collimators have a fixed beam expansion ratio and an unadjustable polarization state, that is, the magnification is fixed and the polarization state changes are ignored. A small hole filter is added between the beam expander and the collimator. Although this can ensure the wavefront of the output light, the output light power is greatly reduced, which is not applicable in many occasions. In order to obtain a large beam expansion ratio, a microscope objective is used as a beam expander. Because the focal length of the microscope objective is very short, the light beam can be expanded greatly, but because the pupil of the microscope objective is very small, the light transmittance is not high, and the beam expansion ratio cannot be changed. Failure to adjust the polarization state will increase the fluctuation of laser power, and the accuracy and stability of the system will be affected. However, only using the wave plate rotation to adjust the polarization state of the input laser cannot be adjusted accurately. Summary of the invention

[0003] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a polarization-adjustable variable-magnification laser beam expander collimator with adjustable warning, adjustable polarization state, continuously adjustable beam expansion ratio, large beam expansion ratio range, high transmittance, and capable of ensuring the quality of the laser beam expansion beam.

[0004] The technical solution adopted by the present invention is: a variable-magnification laser beam expander collimator with adjustable polarization and an adjustment warning, comprising a polarization adjustment device, a beam expander device, a compensation collimator device and a warning device arranged on a collimator lens barrel, wherein:

[0005] The polarization adjustment device comprises a rotatable and adjustable polarization prism and a polarization wave plate which are sequentially arranged in the collimating lens barrel;

[0006] A rotatable and adjustable polarizing prism is placed inside the collimating lens barrel, and one end of the polarizing prism is connected to an adjusting screw to adjust the polarization direction of the light coming out of the polarizing prism, and a hard spring group is connected between the other end and the inner wall of the collimating lens barrel to adjust the polarization direction of the light coming out of the polarizing prism;

[0007] The beam expander device comprises a beam expander lens connected to a polarization wave plate on one side of a collimating lens barrel, and a fine adjustment parallel screw and a coarse adjustment parallel screw which are sequentially sleeved on the outer side of the beam expander lens;

[0008] The compensating collimating lens device comprises a supplementary collimating lens barrel and a collimating lens disposed therein;

[0009] The warning device includes a photocell coating layer coated on the inner wall of a collimator device, a supplementary collimator lens barrel and a compensation collimator lens device, an electric conversion lighting warning light arranged on the outer side of the collimator lens barrel, and a photoelectric conversion circuit for connecting the photocell coating layer and the electric conversion lighting warning light.

[0010] Furthermore, the hard spring group of the polarization adjustment device is fixed to the inner wall of the collimating lens barrel through a fixing structure to optimize the laser utilization rate.

[0011] Furthermore, the hard spring group is a compression spring with a compression amount of 0.5 mm to 2 mm.

[0012] Furthermore, the fine-adjustment parallel screw and the coarse-adjustment parallel screw are fixed at their corresponding positions by means of a fine-adjustment locking screw and a coarse-adjustment locking screw respectively.

[0013] Furthermore, the outer side of the supplementary collimating lens barrel near the beam expander device is also connected to a compensating lens parallel spiral through a thread, and the outer side sleeve of the other end is connected to a compensating lens through a compensating sleeve;

[0014] One of the collimating lens and the compensating lens is a concave lens, and the other is a convex lens, and one of the convex lenses is a double-cemented aberration-correcting lens.

[0015] Furthermore, a compensating locking screw is passed through the wall of the compensation sleeve in the circumferential direction to tighten the supplementary collimating lens barrel, thereby locking the supplementary collimating lens barrel.

[0016] The collimation adjustment method of the variable-magnification laser beam expander collimator is to first install the variable-magnification laser beam expander collimator on an adjustment frame that can be fine-tuned and lifted, remove the compensating collimator device, fine-tune the lifting so that the incident light is incident along the optical axis, and place a white screen 1.7 meters to 2.3 meters away from the exit light port;

[0017] Adjust the fine adjustment parallel screw and the coarse adjustment parallel screw to make the spot diameter on the white screen the same as that at the light outlet. The adjustment of the variable-magnification laser beam expander collimator is completed. Tighten the fine adjustment locking screw and the coarse adjustment locking screw of the fine adjustment parallel screw and the coarse adjustment parallel screw.

[0018] If the spot diameter does not meet the requirements, install a compensating collimator device and rotate the compensating mirror parallel screw for adjustment. During the adjustment, observe whether the electric conversion warning light is on. If it is on, it means that light is scattered to the inner wall of the collimator barrel and the laser utilization rate is low. Then you need to readjust the variable-magnification laser beam expander collimator according to the above steps; if it is not on, after the adjustment is completed, tighten the fine-tuning locking screw and coarse-tuning locking screw of the fine-tuning parallel screw and the coarse-tuning parallel screw.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. It has an adjustable polarization adjustment device. A rotatable polarization prism that is directly adjusted by an adjusting screw is arranged in the collimating lens barrel, and a polarization wave plate is arranged. It is simple to assemble, easy to replace the lens, and has a compact structure.

[0021] 2. The collimation of the beam expander device includes a fine adjustment parallel screw and a coarse adjustment parallel screw, which are used to adjust the distance between the beam expander and the collimating lens to ensure that the focal points of the two coincide so that the outgoing light beam is collimated.

[0022] 3. The electrical conversion of the warning device lights up the warning light to intuitively detect whether there is light scattered into the collimating lens barrel. If it lights up, it means that light is scattered to the inner wall of the collimating lens barrel, which means that the laser utilization rate is low and a compensating collimating lens device is needed to collimate the light.

[0023] 4. The compensating collimator device calibrates and aligns the outgoing light when it is not straight. The compensating collimator device is provided with a compensating mirror parallel spiral and a compensating lens. When the outgoing light is not parallel, a compensating collimator device is added. It changes the distance between the collimating lens and the compensating lens through the compensating mirror parallel spiral, and the light is collimated when the compensation effect is achieved.

[0024] In summary, the variable-power laser beam expander collimator with adjustable polarization and adjustment warning of the present invention can continuously and adjustably expand and collimate the incident laser beam, and can eliminate polarization state changes. At the same time, the ratio of the output light power to the incident light power is greater than 80%, ensuring full utilization of the incident light. The variable-power laser collimator of the present invention has a simple structure, is easy to manufacture, and has low cost. It is widely used in the field of laser and optoelectronic technology. The structure has high adjustment accuracy, is easy to debug and maintain, has a low design cost, and can effectively achieve laser beam expansion. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a complete schematic diagram of the variable-magnification laser beam expansion collimator;

[0026] Figure 2 It is a structural schematic diagram of a variable-power laser beam expansion collimator without a compensation device installed;

[0027] Figure 3 This is a schematic diagram of the beam expansion and collimation optical path system of the present invention;

[0028] Figure 4 This is a schematic diagram of the variable-magnification beam expansion principle of the three-component system with a compensation optical path of the present invention;

[0029] Wherein: 1-collimating lens barrel, 20-polarization adjustment device, 21-rotatable polarizing prism, 22-adjusting screw, 23-hard spring group, 24-polarization wave plate; 30-beam expander device, 31-beam expander lens, 32-fine adjustment parallel screw, 33-coarse adjustment parallel screw, 34-fine adjustment locking screw, 35-coarse adjustment locking screw; 40-compensating collimator device, 41-supplementary collimator lens barrel, 42-collimating lens, 43-compensating lens parallel screw, 44-compensating sleeve, 45-compensating lens, 46-compensating locking screw; 50-warning device, 51-photocell coating layer, 52-electric conversion to light up the warning light. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0031] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the combination or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, in the description of the embodiments of the present invention, the device positional relationships such as "up", "down", "front", "back", "left", "right" and the like in all the drawings are based on the positions or positional relationships shown in the accompanying drawings. Figure 1 As standard.

[0032] like Figure 1 and Figure 2 As shown, a polarization-adjustable variable-magnification laser beam expander collimator with an adjustment warning includes a polarization adjustment device 20, a beam expander device 30, a compensation collimator device 40 and a warning device 50 arranged on a collimator lens barrel 1, wherein:

[0033] The polarization adjustment device 20 includes a rotatable polarization prism 21 and a polarization wave plate 24 which are sequentially arranged in the collimating lens barrel 1.

[0034] The rotatable and adjustable polarizing prism 21 is placed inside the collimating lens barrel 1, and one end of the polarizing prism is connected to the adjusting screw 22 to adjust the polarization direction of the light emitted from the polarizing prism, and the other end is connected to the inner wall of the collimating lens barrel 1 with a hard spring group 23 to adjust the polarization direction of the light emitted from the polarizing prism, that is, the adjusting screw 22 is fixed on the rotatable and adjustable polarizing prism 21, and the rotatable and adjustable polarizing prism 21 can be adjusted in different directions on the same central axis by rotating the adjusting screw 22, thereby adjusting the polarization direction of the light emitted from the polarizing prism. When the central axis of the rotatable and adjustable polarizing prism 21 needs to be adjusted, the adjusting screw 22 can be pressed to compress the hard spring group 23, thereby adjusting the distance of the polarizing prism relative to the central axis of the light, thereby adjusting the polarization direction of the light emitted from the polarizing prism;

[0035] The beam expander device 30 includes a beam expander lens 31 connected to the polarization wave plate 24 on one side of the collimating lens barrel 1, and a fine adjustment parallel screw 32 and a coarse adjustment parallel screw 33 which are sequentially sleeved on the outside of the beam expander lens 31, and the fine adjustment parallel screw 32 and the coarse adjustment parallel screw 33 are used to adjust the distance between the beam expander lens 31 and the collimating lens 42 to ensure that the focal points of the two coincide, so as to collimate the outgoing light beam, thereby achieving collimation;

[0036] When the outgoing light is not parallel and a compensation collimator device 40 is installed, the compensation collimator device 40 includes a supplementary collimator barrel 41 and a collimator lens 42 placed therein, and the compensation collimator device 40 changes the distance between the collimator lens 42 and the compensation lens 45 through the compensation lens parallel spiral 43, so that the light is collimated when the compensation effect is achieved;

[0037] The warning device 50 includes a photocell coating layer 51 coated on the inner wall of the collimator device 30, the supplementary collimator barrel 41 and the compensating collimator device 40, that is, the photocell coating layer 51 is coated along the inner wall of the barrel of the collimator, which has the best effect. The warning device 50 also includes an electric conversion light-on warning light 52 arranged on the outside of the collimator barrel 1, and a photoelectric conversion circuit for connecting the photocell coating layer 51 and the electric conversion light-on warning light 52. The warning device 50 is used to intuitively detect whether there is light scattered into the collimator barrel. If it lights up, it means that there is light scattered to the inner wall of the collimator barrel, which means that the laser utilization rate is low and the compensating collimator device is needed to collimate the light.

[0038] Another preferred embodiment is that the hard spring group 23 of the polarization adjustment device 20 is fixed to the inner wall of the collimating lens barrel 1 through a fixing structure to optimize the laser utilization rate and ensure that the polarizing prism has a good compression effect. The specific implementation method is that the hard spring group 23 is inserted and sleeved inside the fixing structure for use, and the effect of use is good, which can ensure that the polarizing prism has a good polarized light adjustment effect. More preferably, the hard spring group 23 is a compression spring with a compression amount of 0.5mm to 2mm, which has better compression and adjustment effects.

[0039] Another embodiment of the variable-power laser beam expander collimator is that the fine-tuning parallel screw 32 and the coarse-tuning parallel screw 33 are fixed at their corresponding positions by the fine-tuning locking screw 34 and the coarse-tuning locking screw 35 respectively. When the emergent light is not parallel and a compensating collimating lens device is added, the compensating collimating lens device changes the distance between the collimating lens 42 and the compensating lens 45 through the compensating lens parallel screw 43, so that the light is collimated when the compensation effect is achieved.

[0040] In order to ensure that the compensation collimator device 40 of the variable-magnification laser beam expander collimator has a better compensation collimation function, the supplementary collimator barrel 41 is also connected to a compensation mirror parallel spiral 43 through a thread on one end close to the beam expander device 30, and the other end is connected to a compensation lens 45 through a compensation sleeve 44 on the outer side;

[0041] One of the collimating lens 42 and the compensating lens 45 is a concave lens, and the other is a convex lens, and the convex lens is a double cemented aberration-correcting lens.

[0042] The working principle of the compensating collimator device 40 is as follows Figure 1 and Figure 2 As shown, a variable focal length beam expander lens is used to replace a common fixed focal length beam expander lens, the focal length of the collimating lens is fixed, and the beam expansion ratio is adjustable through the combination of the beam expander lens and the compensation lens.

[0043] The laser beam expansion and collimation is realized by combining a concave lens and a convex lens, wherein the convex lens is a double-cemented aberration-correcting lens. According to the Gaussian beam collimation theory, the image focus of the concave lens and the object focus of the convex lens are guaranteed to coincide, and the Gaussian beam collimation effect is the best. At the same time, this lens combination effectively shortens the optical path length. When the focal points do not coincide, a compensating collimator device is used to adjust the focal length of the variable-magnification laser beam expander collimator so that the laser can still achieve collimated output.

[0044] For example, when no compensating collimator device is added, the convex lens with a focal length of 100mm is selected, and the spot diameter after beam expansion and collimation can be 28mm, and the effective spot diameter (the diameter at the 1 / e2 power level in the near field) is 20mm; when a compensating collimator device is added, a concave lens with a practical focal length of 20mm is used to realize the variable magnification group, two double-separated positive lenses with a total focal length of 50mm are used to realize the fixed group, and a single lens with a focal length of 60 is used to realize the compensating group, and the beam expansion ratio can be continuously adjusted from 2x to 15x.

[0045] Compared with the existing adjustable laser beam expander, the variable-power laser beam expander collimator of the present invention is simple to assemble, easy to replace the lens, and has a compact structure.

[0046] The polarization-adjustable variable-magnification laser beam expansion collimator with adjustment warning of the present invention has high structural adjustment accuracy, is easy to debug and maintain, has low design cost, and can effectively achieve laser beam expansion. Furthermore, the compensation sleeve 44 is tightened against the supplementary collimation lens barrel 41 through the compensation locking screw 46 on the circumference of the sleeve 44 through the sleeve wall, thereby locking the supplementary collimation lens barrel 41.

[0047] More specifically, the collimation adjustment method of the variable-power laser beam expander collimator of the present invention is:

[0048] When in use, first install the variable-magnification laser beam expander collimator on an adjustment frame that can be fine-tuned and lifted, remove the compensating collimator device 40, fine-tune the lifting so that the incident light is incident along the optical axis, and place a white screen 1.7 meters to 2.3 meters away from the light outlet;

[0049] Adjust the fine adjustment parallel screw and the coarse adjustment parallel screw to make the spot diameter on the white screen the same as that at the light outlet, and the adjustment of the variable-magnification laser beam expander collimator is completed. Tighten the fine adjustment locking screw 34 and the coarse adjustment locking screw 35 of the fine adjustment parallel screw and the coarse adjustment parallel screw;

[0050] If the spot diameter does not meet the requirements, install the compensating collimator device 40 and rotate the compensating mirror parallel screw 43 to adjust it. During the adjustment, observe whether the electric conversion warning light 52 is on. If it is on, it means that light is scattered to the inner wall of the collimator barrel and the laser utilization rate is low. Then, it is necessary to readjust the variable-magnification laser beam expander collimator according to the above steps; if it is not on, after the adjustment is completed, lock the fine-tuning locking screw 34 and the coarse-tuning locking screw 35 of the fine-tuning parallel screw and the coarse-tuning parallel screw.

[0051] The embodiments of the present invention disclose preferred embodiments, but are not limited thereto. A person skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not deviate from the spirit of the present invention, they are all within the protection scope of the present invention.

Claims

1. Polarization adjustable variable magnification laser beam expander collimator with adjustment warning, characterized by: It comprises a polarization adjustment device (20), a beam expander device (30), a compensation collimator device (40) and a warning device (50) which are arranged on a collimator lens barrel (1), wherein: The polarization adjustment device (20) comprises a rotatable and adjustable polarization prism (21) and a polarization wave plate (24) which are sequentially arranged in the collimating lens barrel (1). A polarizing prism (21) is placed inside the collimating lens barrel (1), and one end of the polarizing prism is connected to an adjusting screw (22), and a hard spring group (23) is connected between the other end and the inner wall of the collimating lens barrel (1) to adjust the polarization direction of light emitted from the polarizing prism; A beam expander device (30) comprises a beam expander lens (31) connected to a side of the collimating lens barrel (1) close to the polarization wave plate (24), and a fine adjustment parallel screw (32) and a coarse adjustment parallel screw (33) which are sequentially sleeved on the outside of the beam expander lens (31); The compensating collimating lens device (40) comprises a supplementary collimating lens barrel (41) and a collimating lens (42) disposed therein; The warning device (50) comprises a photocell coating layer (51) coated on the inner wall of the beam expander device (30) and the compensating collimator device (40), an electric conversion light-emitting warning light (52) arranged on the outer side of the collimator barrel (1), and a photoelectric conversion circuit for connecting the photocell coating layer (51) and the electric conversion light-emitting warning light (52); The supplementary collimating lens barrel (41) is also connected to a compensating lens parallel spiral (43) via a thread on one end close to the beam expander device (30), and the other end is connected to a compensating lens (45) via a compensating sleeve (44) on the outside. One of the collimating lens (42) and the compensating lens (45) is a concave lens, and the other is a convex lens, and one of the convex lenses is a double-cemented aberration-correcting lens.

2. The polarization-adjustable variable-magnification laser beam expander collimator with adjustment warning according to claim 1, characterized in that: The hard spring group (23) of the polarization adjustment device (20) is fixed to the inner wall of the collimating lens barrel (1) via a fixing member structure.

3. The polarization-adjustable variable-power laser beam expander collimator with adjustment warning according to claim 2, characterized in that: The hard spring group (23) is a compression spring with a compression amount of 0.5 mm to 2 mm.

4. The polarization-adjustable variable-magnification laser beam expander collimator with adjustment warning according to claim 1, characterized in that: The fine adjustment parallel screw (32) and the coarse adjustment parallel screw (33) are fixed at their corresponding positions by means of a fine adjustment locking screw (34) and a coarse adjustment locking screw (35), respectively.

5. The polarization-adjustable variable-power laser beam expander collimator with adjustment warning according to claim 1, characterized in that: The compensating sleeve (44) is tightened in the circumferential direction by a compensating locking screw (46) penetrating through the wall of the sleeve to supplement the collimating lens barrel (41).

6. The collimation adjustment method of the polarization-adjustable variable-magnification laser beam expander collimator with adjustment warning according to claim 1 or 5, characterized in that: When in use, the variable-magnification laser beam expander collimator is first mounted on an adjustment frame that can be finely adjusted and lifted, the compensating collimator device (40) is removed, the lifting is finely adjusted so that the incident light is incident along the optical axis, and a white screen is placed 1.7 meters to 2.3 meters away from the light outlet; Adjust the fine adjustment parallel screw and the coarse adjustment parallel screw to make the spot diameter on the white screen the same as that at the light outlet. The adjustment of the variable-magnification laser beam expander collimator is completed. Lock the fine adjustment parallel screw and the coarse adjustment parallel screw. If the spot diameter does not meet the requirement, install a compensating collimator lens device (40) and rotate the compensating lens parallel screw (43) to adjust it. During the adjustment, observe whether the electric conversion light warning light (52) is on. If it is on, it means that light is scattered to the inner wall of the collimator lens barrel and the laser utilization rate is low. Then readjust the variable-magnification laser beam expander collimator. If it is not on, after the adjustment is completed, lock the fine adjustment parallel screw and the coarse adjustment parallel screw.

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