Laser pointing stabilization control device and method based on spot analysis

Abstract

The present invention provides a laser pointing stabilization control device and method based on spot analysis. The device includes multiple modules connected in series, each module having a light entrance and a light exit. The light entrance of the first module is used to receive laser light generated by a laser, and the light exit of the previous module is aligned with the light entrance of the next module. The first module includes a multi-dimensionally adjustable first reflector. The second and subsequent modules each include a second reflector and a camera, wherein the light entrance and light exit are respectively located on the optical axis of the incident light and reflected light of the second reflector, and the camera is located on the transmitted light side of the partial reflector. The second reflectors of the second to the second-to-last modules are multi-dimensionally adjustable partial reflectors, and the second reflector of the last module is a fixed-angle beam splitter. The present invention can monitor and control the stability of the light beam pointing, has a simplified structure, is convenient for adjusting the optical path or troubleshooting, and has a flexible and variable structure.

Description

Technical Field

[0001] The present invention relates to the technical field of light beam pointing stabilization control, and in particular to a laser pointing stabilization control device and method based on light spot analysis. Background Art

[0002] Laser (beam) pointing stability is defined in national standards as twice the standard deviation of the angular displacement of the laser beam perpendicular to its propagation direction. Due to various minor perturbations, the angle of the reflector in the actual optical path may change, causing the final emitted laser light to become unstable and deflected. This stability can also be approximately measured by calculating the coordinate offset of the beam spot projection on a cross-section.

[0003] The role of laser pointing stability in optical systems is primarily reflected in its impact on the accuracy of optical processes or procedures. Higher stability often means higher processing accuracy or measurement results. With the development of industry, laser pointing stability has become increasingly important in practical applications such as laser processing, laser communications, and target indication.

[0004] The existing technologies for laser pointing stability control are as follows:

[0005] (1) In the practical application of equipment in fields such as laser processing, multiple reflectors are often used to form the optical path. When adjusting the optical path, it may be difficult to see the state of the beam inside. Since the adjustment time is very long, if the beam deviates significantly during the adjustment process, the difficulty will be further increased. At the same time, the beam deviation during the processing process may also directly affect the quality of the processing results.

[0006] (2) Existing beam stability control devices only contain one or two reflectors. To reduce the impact of device disturbances, they are usually installed at the end of the device's optical path. In this case, the reflectors in the front optical path are fixed. If the output beam of the laser light source deviates, the reflectors in the front optical path may also need to be adjusted.

[0007] In most machining processes, the laser's offset is small and often takes a long time to accumulate before it has an impact. For example, adjustment is only required every few hours, so the real-time requirement for adjustment is not very high. To meet the needs of such applications, this paper proposes a laser pointing stabilization control device and method based on spot analysis. Summary of the Invention

[0008] The purpose of the present invention is to provide a laser pointing stabilization control device and method based on spot analysis, which is intended to solve the problem that the existing solutions are difficult to adjust and cannot be fully adjusted.

[0009] The present invention is achieved in that:

[0010] In one aspect, the present invention provides a laser pointing stabilization control device based on spot analysis, comprising a plurality of modules connected in series, each module having a light entrance hole and a light exit hole, the light entrance hole of the first module being used to receive laser light generated by a laser, and the light exit hole of the preceding module being aligned with the light entrance hole of the succeeding module;

[0011] The first module includes a multi-dimensionally adjustable first reflector, wherein the adjustment center of the first reflector is fixed and located on the optical axis;

[0012] Each module from the second onwards includes a second reflector and a camera, whose light entrance and light exit holes are respectively located on the optical axis of the incident light and reflected light of the second reflector; the camera is located on the transmitted light side of the partial reflector, and the front end of the camera has a focusing lens; the second reflector of the second to the penultimate module is a multi-dimensionally adjustable partial reflector, and the adjustment center of the partial reflector is fixed and located on the optical axis; the second reflector of the last module is a fixed-angle beam splitter, and the beam splitter is at a 45-degree angle to the optical axis.

[0013] Furthermore, the first reflector is a multi-dimensionally adjustable total reflector.

[0014] Furthermore, the first reflector is a multi-dimensionally adjustable partial reflector, and a camera is provided on the light transmitting side of the first reflector.

[0015] Furthermore, an attenuator is installed between the camera and the second reflector.

[0016] Furthermore, the adjustment centers of the partial reflectors of the second to penultimate modules are coaxial with the center of the photosensitive surface of the corresponding camera, and the camera and lens are perpendicular to the optical axis, and the photosensitive surface of the camera is located on the focal plane of the lens.

[0017] On the other hand, the present invention also provides a laser pointing stabilization control method based on spot analysis, using the laser pointing stabilization control device based on spot analysis as described above, the method comprising the following steps:

[0018] (1) Starting from the second module, check the offset of the spot position in the camera of each module relative to the image center in turn. If the offset is less than the error range, skip it until a module with an offset outside the error range is found;

[0019] (2) According to the offset of the light spot position observed by the camera of the module whose offset exceeds the error range relative to the center of the image, adjust the deflection angle of the reflector in the previous module until the light spot is located in the center of the image;

[0020] (3) Take the same action as in step (2) for the next module, and so on until the second-to-last module.

[0021] Furthermore, the method for adjusting the deflection angle of the reflector in the previous module in step (2) is as follows:

[0022] Assuming that the angle of the laser relative to the optical axis is θ, the offset of the focal spot seen on the camera is Δ, the focal length of the lens is f, and the laser is a parallel beam, then according to the geometric optics principle of convex lens:

[0023] Δ=f*tanθ;

[0024] Through the above relationship, the offset of the laser angle is calculated according to the offset detected by the camera, and then the angle of the reflector θ / 2 is adjusted in the opposite direction.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The laser pointing stabilization control device and method based on spot analysis provided by the present invention monitors and controls the beam pointing stability under the premise that the incident laser is parallel to the optical axis, using the principle that only parallel light propagating parallel to the optical axis can converge at the focal position. The adjustment of each reflector is only related to the camera of the subsequent module, and there is no need to consider the relative positions and influences between multiple modules, which greatly simplifies the structure. The spot image of each reflector in the optical path can be viewed, which is convenient for adjusting the optical path or troubleshooting. Multiple modules can be connected in series, and the reflectors in the modules can be adjusted manually, electrically, piezoelectrically, etc., and the structure is flexible and variable. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic structural diagram of a laser pointing stabilization control device based on spot analysis provided by an embodiment of the present invention;

[0028] Figure 2 A structural diagram of the second and subsequent modules provided in an embodiment of the present invention;

[0029] Figure 3 This is a flowchart of a laser pointing stabilization control device based on spot analysis provided by an embodiment of the present invention.

[0030] Explanation of reference numerals: 1-light entrance hole, 2-light exit hole, 3-second reflector, 4-camera, 5-lens. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a laser pointing stabilization control device based on spot analysis, comprising a plurality of modules connected in series, each module having a light entrance hole 1 and a light exit hole 2, the light entrance hole 1 of the first module being used to receive laser light generated by a laser, and the light exit hole 2 of the previous module being aligned with the light entrance hole 1 of the next module; the first module comprising a multi-dimensionally adjustable first reflector, which can adjust the deflection angle in the X or Y direction, and the adjustment center of the first reflector is fixed and located on the optical axis; the second and subsequent modules each comprise a second reflector 3 and a camera 4, the light entrance hole 1 and the light exit hole 2 of these modules being respectively located on the optical axis where the incident light and the reflected light of the second reflector are located, the camera 4 being located on the transmitted light side of the partial reflector 3, and the front end of the camera 4 having a focusing lens 5 for monitoring the position where the incident light hits the second reflector 3. The second reflector 3 of each module from the second to the penultimate module, that is, between the first module and the last module, is a multi-dimensionally adjustable partial reflector, and the adjustment center of the partial reflector is fixed and located on the optical axis. The partial reflector can select a suitable transmittance according to actual conditions; the second reflector 3 of the last module is a beam splitter with a fixed angle, and its angle cannot be adjusted. The beam splitter is at a 45-degree angle to the optical axis and can be installed in a fixed manner. Optionally, the transmission and reflection optical paths of the last module are interchangeable, that is, the monitoring camera can be installed on the reflection or transmission surface according to actual application conditions. Generally, the device includes at least two modules at the head and tail, and the specific number of modules can be changed according to actual needs such as the optical path length of the equipment and the number of reflections. Each reflector can be adjusted manually, electrically, piezoelectrically, etc., according to actual needs.

[0033] In one embodiment, the first module is not provided with a camera, and the first reflector is a multi-dimensionally adjustable full reflector. In another embodiment, the first reflector is a multi-dimensionally adjustable partial reflector, and a camera is provided on the light transmission side of the first reflector for monitoring the stability of the laser.

[0034] Preferably, an attenuator is installed between the camera 4 and the second reflector 3 to control the intensity of the laser entering the camera. The attenuator can be an electrically adjustable attenuator or a manually adjustable attenuator.

[0035] Furthermore, the adjustment centers of the partial reflectors of the second to penultimate modules are coaxial with the center of the photosensitive surface of the corresponding camera 4, and the camera 4 and the lens 5 are perpendicular to the optical axis, and the photosensitive surface of the camera 4 is located on the focal plane of the lens 5.

[0036] When the device is working properly, the laser generates laser light, which enters the center of the first module's light inlet 1 parallel to the optical axis and hits the first module's adjustable reflector. Then, it enters the second module from the first module's light outlet 2 parallel to the optical axis and hits the second module's adjustable reflector. The camera 4 in the second module will now see the light spot at the exact center of the image, so there is no need to adjust the reflector. The laser light will be directly reflected from the center of the reflector to the next module. This process continues in this way until the laser light passes through all modules. Figure 3 shown.

[0037] In this embodiment, the camera's photosensitive surface is located on the focal plane of the lens. Geometric optics shows that the laser beam converges at the focal point only when it is incident parallel to the optical axis. At this point, the light spot seen by the camera is located at the center of the image. Parallel light incident at other angles will converge at other points on the focal plane. Therefore, by using the camera in the module to monitor the offset of the light spot relative to the image center, and then adjusting the deflection angle of the reflector in the previous module based on this offset to move the light spot to the image center, the beam can be ensured to remain parallel to the optical axis. Because the laser light generated by the laser is incident along the optical axis, the entire optical path after adjustment is theoretically standard and correct.

[0038] An embodiment of the present invention further provides a laser pointing stabilization control method based on spot analysis, which uses the above-mentioned laser pointing stabilization control device based on spot analysis. The method is as follows:

[0039] When a reflector is offset, for example, module n, the laser between the reflectors of modules n and n+1 will no longer be parallel to the optical axis. However, the optical path in front of module n remains correct. Follow the steps below to adjust the reflector:

[0040] (1) Starting from the second module, check the offset of the light spot position relative to the image center in the camera of each module in turn. If the offset is less than the error range, skip it until a module with an offset outside the error range is found. The error range is determined by the requirements of the entire optical system. In this embodiment, the camera of module n can see that the light spot is located at the center of the image, while the camera of module n+1 can see that the light spot is not at the center of the image.

[0041] (2) According to the offset of the light spot position observed by the camera of module n+1 relative to the center of the image, adjust the deflection angle of the reflector in module n until the light spot is located in the center of the image. The specific adjustment method is as follows:

[0042] Assuming that the angle of the laser relative to the optical axis is θ, the offset of the focal spot seen on the camera is Δ, the focal length of the lens is f, and the laser is a parallel beam, then according to the geometric optics principle of convex lens:

[0043] Δ=f*tanθ;

[0044] Using the above relationship, the laser angle offset can be calculated based on the offset observed by the camera. The reflector angle can then be adjusted in the opposite direction by adjusting the angle θ / 2. This adjustment can be done manually, using computer feedback control, or by other means. Based on the principles described above, the laser should now propagate along its original optical path.

[0045] (3) The structure of module n+2 is the same as that of module n+1. After step (2) is completed, the same operation as in step (2) is performed in module n+2, adjusting the reflector of module n+1 until the light spot in the camera of module n+2 is at the center of the image, and so on until the second-to-last module.

[0046] Since the last module is a beam splitter fixed at a standard angle, no adjustment is necessary.

[0047] The above adjustment process can be performed once at regular intervals, or can be performed continuously in real time as required.

[0048] If the laser is misaligned when incident and the incident light does not coincide with the optical axis, the solution will still work as long as the beam is parallel to the optical axis and is not blocked.

[0049] It should be noted that, in the subsequent reflection light path of this device, if the control of pointing stability is not required, the adjustable reflector can be replaced by a fixed reflector.

[0050] In summary, the laser pointing stabilization control device and method based on light spot analysis provided by the embodiments of the present invention, under the premise that the incident laser is parallel to the optical axis, uses the principle that only parallel light propagating parallel to the optical axis can converge at the focal position to complete the monitoring and control of the light beam pointing stability; the adjustment of each reflector is only related to the camera of the subsequent module, and there is no need to consider the relative positions and their influences between multiple modules, and the structure is greatly simplified; the light spot image passed by each reflector in the optical path can be viewed, which is convenient for adjusting the optical path or troubleshooting; multiple modules can be connected in series, and the reflectors in the modules can be adjusted manually, electrically, piezoelectrically, etc., and the structure is flexible and variable.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A laser pointing stabilization control device based on spot analysis, characterized by: It includes multiple modules connected in series, each module has a light entrance hole and a light exit hole, the light entrance hole of the first module is used to receive the laser light generated by the laser, and the light exit hole of the previous module is aligned with the light entrance hole of the next module; The first module includes a multi-dimensionally adjustable first reflector, wherein the adjustment center of the first reflector is fixed and located on the optical axis; Each module from the second onwards includes a second reflector and a camera, whose light entrance and light exit holes are located on the optical axis of the incident light and reflected light of the second reflector, respectively. The second reflectors of the second to the penultimate modules are multi-dimensionally adjustable partial reflectors, and the adjustment center of the partial reflectors is fixed and located on the optical axis. The camera is located on the transmitted light side of the partial reflector, and the front end of the camera has a focusing lens. The second reflector of the last module is a fixed-angle beam splitter, and the beam splitter is at a 45-degree angle to the optical axis. The camera in the module monitors the offset of the light spot position relative to the image center. Based on this offset, the deflection angle of the reflector in the previous module is adjusted to move the light spot to the image center, ensuring that the light beam is always parallel to the optical axis. Assuming that the angle of the laser relative to the optical axis is θ, the offset of the focal spot seen on the camera is Δ, the focal length of the lens is f, and the laser is a parallel beam, the geometric optical principles of a convex lens show that: Δ=f*tanθ; Through the above relationship, the offset of the laser angle is calculated according to the offset detected by the camera, and then the angle of the reflector θ / 2 is adjusted in the opposite direction; The adjustment centers of the partial reflectors of the second to penultimate modules are coaxial with the centers of the photosensitive surfaces of the corresponding cameras, and the cameras and lenses are perpendicular to the optical axis, and the photosensitive surfaces of the cameras are located on the focal plane of the lens; When the device is working normally, the laser generates laser light, which enters the first module from the center of the light entrance hole parallel to the optical axis and hits the first adjustable reflector of the first module. Then, the laser light enters the second module from the light exit hole of the first module parallel to the optical axis and hits the adjustable reflector of the second module. The camera in the second module will see that the light spot is located in the center of the image at this time, so there is no need to adjust the reflector. The laser light will be directly reflected from the center of the reflector to the next module until the laser light passes through all modules.

2. The laser pointing stabilization control device based on spot analysis according to claim 1, characterized in that: The first reflector is a multi-dimensionally adjustable total reflector.

3. The laser pointing stabilization control device based on spot analysis according to claim 1, characterized in that: The first reflector is a multi-dimensionally adjustable partial reflector, and a camera is provided on the light transmitting side of the first reflector.

4. The laser pointing stabilization control device based on spot analysis according to claim 1, characterized in that: An attenuator is installed between the camera and the second reflector.

5. A laser pointing stabilization control method based on spot analysis, characterized in that: Using the laser pointing stabilization control device based on spot analysis according to any one of claims 1 to 4, the method comprises the following steps: (1) Starting from the second module, check the offset of the spot position in the camera of each module relative to the image center in turn. If the offset is less than the error range, skip it until a module with an offset outside the error range is found; (2) According to the offset of the light spot position observed by the camera of the module whose offset exceeds the error range relative to the image center, adjust the deflection angle of the reflector in the previous module until the light spot is located in the center of the image; (3) Take the same action as in step (2) for the next module, and so on until the second-to-last module.

6. The laser pointing stabilization control method based on spot analysis according to claim 5, characterized in that: The method for adjusting the deflection angle of the reflector in the previous module in step (2) is as follows: Assuming that the angle of the laser relative to the optical axis is θ, the offset of the focal spot seen on the camera is Δ, the focal length of the lens is f, and the laser is a parallel beam, then according to the geometric optics principle of convex lens: Δ=f*tanθ; Through the above relationship, the offset of the laser angle is calculated according to the offset detected by the camera, and then the angle of the reflector θ / 2 is adjusted in the opposite direction.

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