Method for reducing light spot distortion, lens and optical system

Abstract

This application is applicable to the field of optical technology and provides a method, lens, and optical system for reducing light spot distortion. The method includes: obtaining the propagation direction of a square light spot formed after laser light passes through a light spot shaping element; placing a special lens at the outer end of the light spot shaping element along the propagation direction of the square light spot; the special lens comprises a middle portion, a waist portion, and an edge portion; the middle portion, waist portion, and edge portion have different curvatures; calculating the change in optical path difference at different positions of the special lens when the square light spot passes through the special lens; controlling the position of the square light spot passing through the special lens, and based on the change in optical path difference at different positions, dynamically adjusting the curvature of the middle portion, waist portion, and edge portion to compensate for the optical path difference at different positions to reduce light spot distortion. This application can achieve wide-angle laser output while ensuring light spot homogenization.

Description

Technical Field

[0001] The present application belongs to the field of optical technology, and in particular relates to a method for reducing light spot distortion, a lens, and an optical system. Background Art

[0002] In existing technologies, the application of surface spot light has become increasingly widespread. However, the laser surface spot light sources currently on the market generally have a small angle, which leads to certain limitations in their use. To meet the needs of wider-angle lighting, spot shaping technology can be used.

[0003] Traditionally, there are three main ways to achieve a surface light spot: the Diffractive Optical Elements (DOE) method, the Powell superposition method, and the cylindrical array method. The DOE diffractive optical element achieves the surface light spot effect by diffraction, while the Powell superposition method uses two Powell prisms to shape the light into a square light spot, and the cylindrical array method uses two cylindrical arrays to superimpose to achieve the shaping effect. However, these methods all have large distortion problems when shooting large-angle lasers, which will have an adverse effect on the homogenization of the entire light spot and will result in a lot of energy waste.

[0004] Due to the distortion and energy waste of traditional surface spot methods at large angles, they are unable to meet the needs of large-angle lighting. Spot shaping technology faces significant challenges. How to achieve large-angle laser output while ensuring spot homogenization has become a technical problem that needs to be solved urgently. Summary of the Invention

[0005] To overcome the problems existing in the related art, the embodiments of the present application provide a method, lens, and optical system for reducing light spot distortion, which can achieve large-angle laser output while ensuring light spot homogenization.

[0006] This application is achieved through the following technical solutions:

[0007] In a first aspect, an embodiment of the present application provides a method for reducing light spot distortion, comprising:

[0008] Obtain the propagation direction of the square spot formed after the laser passes through the spot shaping element;

[0009] At the outer end of the light spot shaping element, a special lens is set along the propagation direction of the square light spot; the special lens consists of a middle part, a waist part and an edge part; the curvatures of the middle part, the waist part and the edge part are different;

[0010] Calculate the optical path difference of a square light spot passing through different positions of a special lens;

[0011] The position of the square light spot passing through the special lens is controlled, and based on the changes in the optical path difference at different positions, the curvature of the middle, waist and edge positions is dynamically adjusted to compensate for the optical path difference at different positions to reduce the light spot distortion.

[0012] In a possible implementation manner of the first aspect, the curvature of the middle portion is greater than the curvature of the waist portion, and the curvature of the edge portion is greater than the curvature of the waist portion.

[0013] In a possible implementation of the first aspect, controlling the position of the square light spot passing through the special lens includes:

[0014] Based on the changes in optical path difference at different positions, the four corners of the square light spot are controlled to pass through the edge positions of the special lens, the middle areas of each edge of the square light spot are controlled to pass through the middle of the special lens, and the middle area of ​​the square light spot is controlled to pass through the middle of the special lens.

[0015] In a possible implementation of the first aspect, based on changes in optical path differences at different positions, dynamically adjusting the curvatures of the middle, waist, and edge positions to compensate for the optical path differences at different positions includes:

[0016] Determine the degree of distortion based on the degree of change in optical path difference at different positions;

[0017] Based on the degree of distortion, the curvature of the middle, waist and edge positions is adjusted to compensate for the optical path difference at different positions.

[0018] In a possible implementation of the first aspect, adjusting the curvatures of the middle, waist, and edge positions based on the degree of distortion includes:

[0019] The greater the degree of distortion, the greater the change in curvature from the edge position to the waist.

[0020] In a possible implementation of the first aspect, obtaining a propagation direction of a square light spot formed after the laser passes through a light spot shaping element includes:

[0021] Define the surface equation of the spot shaping element;

[0022] Based on the surface equation of the spot shaping element, the propagation direction model of the square spot formed after the laser passes through the spot shaping element is determined.

[0023] In a possible implementation of the first aspect, the mathematical model z(x, y) of the surface shape of the custom lens is expressed as:

[0024] z(x,y)=Cx 2 +Dy 2

[0025] Wherein, (x, y) is the coordinate of any position of the custom lens; C is the curvature constant of the custom lens in the x direction, and D is the curvature constant of the custom lens in the y direction.

[0026] In a possible implementation of the first aspect, at the outer end of the light spot shaping element, if the angle at which the light spot shaping element generates the square light spot is larger, then when a special lens is provided along the propagation direction of the square light spot, the distance between the special lens and the front end light spot shaping element is closer.

[0027] On the second aspect, an embodiment of the present application provides a lens for reducing spot distortion, which is a special lens and is arranged at the outer end of the spot shaping element along the propagation direction of the square spot; the special lens consists of a middle part, a waist and an edge position; the curvatures of the middle part, the waist and the edge positions are different; wherein, by controlling the position of the square spot passing through the special lens, and based on the change in the optical path difference of the square spot passing through different positions of the special lens, the curvatures of the middle part, the waist and the edge positions are dynamically adjusted to compensate for the optical path difference at different positions to reduce the spot distortion.

[0028] In a third aspect, an embodiment of the present application provides an optical system for reducing spot distortion, comprising a spot shaping element and a special lens as in the second aspect.

[0029] It can be understood that the beneficial effects of the second and third aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0030] Compared with the related art, the embodiments of the present application have the following beneficial effects:

[0031] In an embodiment of the present application, by calculating the change in optical path difference of a square light spot passing through different positions of a special lens, the source of light spot distortion can be accurately identified, so that the light spot can be more evenly distributed when passing through the lens, thereby significantly improving the homogenization effect of the light spot. Subsequently, by dynamically adjusting the curvature of the middle, waist and edge positions of the special lens, the optical path difference at these positions can be compensated in a targeted manner, thereby ensuring that the laser can maintain a larger angular range when output. By dynamically adjusting the curvature of the special lens, dynamic adjustments can be made according to different light spot distortion conditions. This method can be applied to a variety of optical systems, whether it is a simple lens system or a complex multi-lens system. Better imaging effects can be achieved through this method, and ultimately, by reducing light spot distortion, image quality can be significantly improved. This is of particular importance for fields requiring high-precision imaging, such as optical measurement, optical detection, and medical imaging.

[0032] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0034] Figure 1 1 is a schematic structural diagram of a fly-eye lens provided in one embodiment of the present application;

[0035] Figure 2 is a structural diagram of a cylindrical array provided in one embodiment of the present application;

[0036] Figure 3 This is a schematic diagram of square spot distortion provided by an embodiment of the present application;

[0037] Figure 4 1 is a flow chart of a method for reducing light spot distortion provided by an embodiment of the present application;

[0038] Figure 5 This is a schematic diagram of the correspondence between the custom lens provided in one embodiment of the present application and the position of the distorted light spot before correction;

[0039] Figure 6 Schematic diagram of a square light spot after distortion correction provided by an embodiment of the present application. DETAILED DESCRIPTION

[0040] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail.

[0041] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0042] It will also be understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0043] As used in the present specification and the appended claims, the terms "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0044] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0045] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0046] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] It's important to understand that a small-angle surface spot typically refers to a spot with a narrow divergence angle. This means the light is relatively concentrated during propagation, resulting in a narrow illumination range. This type of surface spot is common in applications such as laser scanning, laser cutting, and laser welding. Due to the small divergence angle, the light can be more precisely focused on the target area, enabling high-precision processing or measurement.

[0048] A wide-angle surface light spot has a wide divergence angle, meaning the light is relatively dispersed during propagation, resulting in a wider illumination range. This type of surface light spot is widely used in lighting, display, environmental monitoring, and other fields. Due to the wide divergence angle, the light can cover a wider area, providing uniform illumination or detection effects.

[0049] Currently, there are solutions on the market that use DOE diffraction plates to shape the light spot into a square, but the cost is very high, and the cost is even higher when high uniformity is required. In the case of large angles, the energy at the edge of the light spot will be low. In addition, there are solutions that use compound eye lenses, such as Figure 1As shown, the light spot is shaped into a square. This method has high light spot uniformity, but the light spot angle size is too small and cannot be used in large-angle applications.

[0050] There are also two cylindrical arrays placed vertically, such as Figure 2 As shown in the figure, the light spot is shaped into a line, and then the line spot is widened to obtain a surface spot. However, the large-angle light spot obtained in this way will have a large distortion, such as Figure 3 shown.

[0051] Therefore, in combination with the aforementioned background technology, it can be understood that it is currently difficult to achieve large-angle laser output while ensuring uniform light spot.

[0052] Figure 4 FIG. 1 is a flow chart of a method for reducing light spot distortion provided by an embodiment of the present application. Figure 4 , the method for reducing spot distortion is described in detail as follows:

[0053] Step 101 : Acquire the propagation direction of the square light spot formed after the laser passes through the light spot shaping element.

[0054] For example, the laser light can be parallel, focused, or diffused. After passing through the spot shaping element, the spot is shaped into a linear spot. The spot shaping element can be a DOE diffractive optical element, a Powell lens, a cylindrical array, a fly-eye lens, or any combination thereof, capable of shaping a linear spot.

[0055] The incident laser will be converted into a linear spot under the influence of the spot shaping element. After the light passes through the spot shaping element, the propagation direction of the light changes. Therefore, it is necessary to use the characteristics of the spot shaping element to redefine the propagation direction of the formed square spot.

[0056] Step 102: a special lens is provided at the outer end of the light spot shaping element along the propagation direction of the square light spot.

[0057] The custom lens is composed of a center, waist, and edge sections, each with different curvatures. This allows for targeted correction of the distorted square light spot.

[0058] Step 103 , calculating the change in optical path difference of the square light spot passing through different positions of the special lens.

[0059] At different positions of the custom lens, the curvature changes differently, which will result in different changes in the optical path of the light path. This change is particularly obvious at the edge position. Therefore, the changes in the optical path difference at different positions of the custom lens can be grasped, which in turn prepares for customizing the curvature of the custom lens to correspond to the distortion.

[0060] Step 104 controls the position of the square light spot passing through the special lens, and dynamically adjusts the curvature of the middle, waist and edge positions based on the change of the optical path difference at different positions to compensate for the optical path difference at different positions to reduce the light spot distortion.

[0061] This embodiment calculates the optical path difference of a square light spot as it passes through different locations on a custom lens, accurately identifying the source of light spot distortion. This allows for a more even distribution of the light spot as it passes through the lens, significantly improving the homogenization of the light spot. Subsequently, by dynamically adjusting the curvature of the custom lens at the center, waist, and edges, it can specifically compensate for the optical path difference at these locations, ensuring that the laser output maintains a wide angular range. By dynamically adjusting the curvature of the custom lens to accommodate varying light spot distortion conditions, it can mitigate light spot distortion and achieve better imaging results.

[0062] In one embodiment, a process for determining the propagation direction of a square light spot formed after laser light passes through a light spot shaping element is described. Step 101 includes:

[0063] First, define the surface equation of the spot shaping element.

[0064] The surface equation of the spot shaping element can be defined according to the characteristics of each element having the function of shaping a linear spot, such as a DOE diffractive optical element, a Powell lens, a cylindrical array, or a fly-eye lens.

[0065] For example, taking a cylindrical array as an example, the surface equation of the cylindrical array is defined as z = f(x, y). Here, f(x, y) is a function that describes the curvature of the cylindrical array. The incident parallel light will be converted into a linear light spot under the influence of the cylindrical array.

[0066] Then, based on the surface equation of the spot shaping element, the propagation direction model of the square spot formed after the laser passes through the spot shaping element is determined.

[0067] After the light passes through the cylindrical array, the propagation direction R of the light changes, and the corresponding propagation direction model of the square light spot can be expressed as:

[0068]

[0069] The cylindrical array makes the incident light converge in the horizontal coordinate direction to form a linear light spot. After passing through two intersecting cylindrical arrays, a surface light spot is formed, but there will be distortion.

[0070] This embodiment lays the foundation for subsequent distortion determination by using the propagation direction model of the square light spot.

[0071] In one embodiment, it is described how to customize the curvature of a lens at the center, waist, and edge.

[0072] Exemplarily, the curvature of the middle portion is greater than that of the waist portion, and the curvature of the edge portion is greater than that of the waist portion.

[0073] At the outer end of the cylindrical array, a special lens, such as Figure 5 As shown in the figure, the square light spot passes through the middle of the lens, where the curvature is approximately flat, which has almost no effect on the optical path and the optical path change is small. There is a gentle curvature change at the waist, which causes the optical path to change, and the optical path difference is relatively small. There is a significant curvature change at the edge, and the optical path change is particularly obvious, with a larger optical path difference.

[0074] The mathematical model z(x,y) of the surface shape of the custom lens is expressed as:

[0075] z(x,y)=Cx 2 +Dy 2

[0076] Wherein, (x, y) is the coordinate of any position of the custom lens; C is the curvature constant of the custom lens in the x direction, and D is the curvature constant of the custom lens in the y direction.

[0077] For example, the curvature of the edge position may range from 10 to 25 (the unit of curvature is not marked, and is m). -1 ), the curvature of the waist can range from 25 to 50, and the curvature of the center can range from 50 to infinity (plane).

[0078] The curvature at the edge is set to 10-25°. Within this area, the light path bends significantly, resulting in a significant change in the optical path difference. The curvature at the waist is set to 25-50°. The curvature change in this area is relatively gentle, and the optical path difference change is relatively small, but it still has an impact. The curvature in the middle is 50°, which is close to infinity (i.e., a flat surface). Within this area, the optical path difference is close to zero, and the light path hardly changes.

[0079] The curvature piecewise function of the custom lens can be expressed as:

[0080]

[0081] Among them, C1 is the curvature constant of the edge position of the special lens in the x direction, D1 is the curvature constant of the edge position of the special lens in the y direction; C2 is the curvature constant of the edge position of the special lens in the x direction, D2 is the curvature constant of the edge position of the special lens in the y direction; C3 is the curvature constant of the edge position of the special lens in the x direction, D3 is the curvature constant of the edge position of the special lens in the y direction; as x and y increase, the curvature gradually increases.

[0082] Next, in step 103, we can use the optical path formula to calculate the optical path difference when the light passes through different positions of the lens. Assume that the light passes through the lens surface from the incident point (x0, y0, z0) and is refracted along the direction R = (R x ,R y ,R z ) propagation, the change in lens curvature will cause the optical path difference of the light propagation path.

[0083] The optical path difference can be calculated using the following formula:

[0084] ΔL=∫ 光线轨迹 n(x,y)dl

[0085] Here, n(x,y) is the refractive index at (x,y), dl is the slight change in the light path, and the integral range is the ray trajectory from the point of incidence to the point of exit, where the exit point is determined by the point of incidence and the propagation direction R. The optical path difference varies for different areas of the lens, depending on the lens curvature and the angle of incidence of the light. Due to the change in curvature, light will be refracted at different angles when passing through different areas of the lens, affecting the magnitude of the optical path difference. Especially when the spot distortion is large, the curvature change from the edge to the waist needs to be increased to compensate for the imaging distortion caused by the irregular optical path difference.

[0086] Since the light spot is a square spot, the light spots at the four corners of the light spot act differently on the middle, waist and edge of the lens, which will form different optical path differences, thereby correcting the distortion.

[0087] Exemplarily, in step 104, controlling the position of the square light spot passing through the custom lens includes:

[0088] Based on the changes in optical path difference at different positions, the four corners of the square light spot are controlled to pass through the edge positions of the special lens, the middle areas of each edge of the square light spot are controlled to pass through the middle of the special lens, and the middle area of ​​the square light spot is controlled to pass through the middle of the special lens.

[0089] like Figure 5 As shown, the maximum distortion of the four sides of the square light spot's pincushion distortion is tangent to the dividing line between the middle and waist, so that the circle enclosed by the maximum distortion is in the middle. This part of the light spot is mostly uniform and requires almost no correction. The part outside the circle enclosed by the maximum distortion is aligned with the waist and edge positions according to the direction of the four corners. The four corners of the square light spot act on the edge positions of the special lens respectively, and the concave part of the pincushion distortion gradually transitions from the edge position to the waist to form a corresponding position. The curvature changes at different positions according to the different degrees of distortion, compensating for the corresponding optical path difference, and reducing the light spot distortion. The square light spot after reducing the light spot distortion is as follows: Figure 6 shown.

[0090] Here, pincushion distortion is the main distortion form of the square surface spot during application, and barrel distortion generally does not occur. Therefore, this application only describes the relevant solutions for pincushion distortion.

[0091] Therefore, in step 104, based on the change in optical path difference at different positions, the curvatures at the middle, waist and edge positions are dynamically adjusted to compensate for the optical path difference at different positions, including:

[0092] The degree of distortion is determined based on the change in optical path difference at different locations. Based on the degree of distortion, the curvature of the center, waist, and edges is adjusted to compensate for the optical path difference at different locations.

[0093] Exemplarily, based on the degree of distortion, adjusting the curvature of the middle, waist, and edge positions includes:

[0094] The greater the degree of distortion, the greater the change in curvature from the edge position to the waist.

[0095] It's important to note that, in addition to cylindrical arrays, Powell prisms and cylindrical lenses also have similar effects on the shaping and distortion of the light spot. They all bend light at a certain angle, changing the shape of the light spot. The optical path difference of Powell prisms and cylindrical lenses is similar to the change in curvature of a lens, and they can compensate for distortion by adjusting the refractive path of light.

[0096] This embodiment can effectively control the propagation path and optical path difference of light by designing the curvature of different positions of the special lens, such as the curvature difference at the middle, waist and edge positions. For square light spots, the distortion can be corrected in a targeted manner according to their different effects in different areas of the lens (middle, waist, edge). When dealing with pincushion-shaped distortion of the light spot, the curvature changes at different positions can be adjusted according to different degrees of distortion, thereby compensating for the corresponding optical path difference and achieving a better light spot shaping effect. Moreover, this principle of using the curvature of a special lens to adjust the optical path difference to compensate for distortion is similar to that of a Powell prism and a cylindrical lens. It has certain reference value for studying the shaping and distortion control of light spots, and can be widely used in scenarios in optical systems that require precise control of the light spot shape and correction of distortion, thereby improving the imaging quality of the optical system.

[0097] Furthermore, with the continuous advancement of technology, the requirements for spot shaping and distortion correction are becoming increasingly stringent. In the future, more advanced optical components or combinations may emerge that can more efficiently and accurately handle the distortion of various spot shapes. For example, an intelligent control system could monitor spot distortion in real time and automatically adjust the parameters of specialized lenses, Powell prisms, or cylindrical lenses based on the monitoring results, achieving adaptive spot shaping and distortion correction. This approach will have broad application prospects in numerous fields, including laser processing and optical imaging.

[0098] In one embodiment, the placement of the custom lens is related to the angle at which the square light spot is generated. At the outer end of the light shaping element, the larger the angle at which the light shaping element generates the square light spot, the closer the custom lens is to the front end of the light shaping element when a custom lens is positioned along the propagation direction of the square light spot.

[0099] For example, if the angle created by the light shaping element (cylindrical array, Powell lens, cylindrical lens, or a combination thereof) that produces a square light spot is larger, the distance between the custom lens and the front lens assembly is closer. For example, at a full angle of 53°, the distance between the custom lens and the front light shaping element is 20mm to 35mm.

[0100] The angle θ produced by the light shaping element that produces a square light spot is expressed as:

[0101] θ=α+Δθ

[0102] Where α is the incident angle of the light onto the custom lens, and Δθ is the angle change caused by the distance d between the custom lens and the front group's spot shaping element.

[0103] The method for reducing light spot distortion provided in the embodiment of the present application can accurately identify the source of light spot distortion by calculating the change in optical path difference of a square light spot passing through different positions of a special lens, so that the light spot can be more evenly distributed when passing through the lens, thereby significantly improving the homogenization effect of the light spot. Subsequently, by dynamically adjusting the curvature of the middle, waist and edge positions of the special lens, the optical path difference at these positions can be compensated in a targeted manner, thereby ensuring that the laser can maintain a larger angular range when output. By dynamically adjusting the curvature of the special lens, dynamic adjustment can be made according to different light spot distortion conditions. It can be applied to a variety of optical systems, whether it is a simple lens system or a complex multi-lens system, and better imaging effects can be obtained through this method. Ultimately, by reducing light spot distortion, the image quality is significantly improved. This is of particular importance for fields requiring high-precision imaging, such as optical measurement, optical detection, medical imaging, etc.

[0104] An embodiment of the present application provides a lens for reducing spot distortion. The lens is a special lens and is arranged at the outer end of a spot shaping element along the propagation direction of a square spot. The special lens consists of a middle part, a waist part, and an edge part. The curvatures of the middle part, the waist part, and the edge part are different. The curvatures of the middle part, the waist part, and the edge part are dynamically adjusted based on the change in the optical path difference of the square spot passing through different positions of the special lens by controlling the position of the square spot passing through the special lens to compensate for the optical path difference at different positions, thereby reducing spot distortion.

[0105] An embodiment of the present application provides an optical system for reducing light spot distortion, including a light spot shaping element and a special lens as described in the above embodiment.

[0106] It is understandable that the beneficial effects of the above-mentioned lens for reducing spot distortion and the optical system for reducing spot distortion can be found in the relevant description of the above-mentioned method for reducing spot distortion, and will not be repeated here.

[0107] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0108] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A method for reducing spot distortion, characterized in that: include: Obtain the propagation direction of the square spot formed after the laser passes through the spot shaping element; A special lens is provided at the outer end of the light spot shaping element along the propagation direction of the square light spot; the special lens consists of a middle portion, a waist portion, and an edge portion; the curvatures of the middle portion, the waist portion, and the edge portion are different; Calculate the change in optical path difference of the square light spot passing through different positions of the special lens; The position where the square light spot passes through the special lens is controlled, and based on the change in the optical path difference at different positions, the curvatures of the middle, waist and edge positions are dynamically adjusted to compensate for the optical path difference at different positions to reduce the light spot distortion.

2. The method for reducing spot distortion according to claim 1, wherein: The curvature of the middle portion is greater than that of the waist portion, and the curvature of the edge portion is greater than that of the waist portion.

3. The method for reducing spot distortion according to claim 2, wherein: The controlling the position of the square light spot passing through the special lens includes: Based on the change in the optical path difference at different positions, the four corners of the square light spot are controlled to pass through the edge positions of the special lens, the middle areas of each edge of the square light spot are controlled to pass through the middle of the special lens, and the middle area of ​​the square light spot is controlled to pass through the middle of the special lens.

4. The method for reducing spot distortion according to claim 1, wherein: The method of dynamically adjusting the curvatures of the middle portion, the waist portion, and the edge portion based on the change in the optical path difference at the different positions to compensate for the optical path difference at the different positions includes: Determining the degree of distortion based on the degree of change in the optical path difference at different positions; Based on the degree of distortion, the curvatures of the middle portion, the waist portion, and the edge portion are adjusted to compensate for the optical path differences at different positions.

5. The method for reducing spot distortion according to claim 4, wherein: The adjusting the curvatures of the middle portion, the waist portion, and the edge portion based on the degree of distortion includes: The greater the degree of distortion, the greater the degree of change in curvature of the waist when adjusting the edge position.

6. The method for reducing spot distortion according to claim 1, wherein: The obtaining of the propagation direction of the square light spot formed after the laser passes through the light spot shaping element includes: defining a surface equation of the light spot shaping element; Based on the surface equation of the light spot shaping element, a propagation direction model of the square light spot formed after the laser passes through the light spot shaping element is determined.

7. The method for reducing spot distortion according to claim 1, wherein: The mathematical model z(x,y) of the surface shape of the custom lens is expressed as: z(x,y)=Cx 2 +Dy 2 Wherein, (x, y) is the coordinate of any position of the special lens; C is the curvature constant of the special lens in the x direction, and D is the curvature constant of the special lens in the y direction.

8. The method for reducing spot distortion according to any one of claims 1 to 7, wherein: At the outer end of the light spot shaping element, if the angle at which the light spot shaping element generates the square light spot is larger, then when a special lens is set along the propagation direction of the square light spot, the distance between the special lens and the front end of the light spot shaping element is closer.

9. A lens for reducing spot distortion, characterized in that: The lens is a special lens, which is arranged at the outer end of the light spot shaping element along the propagation direction of the square light spot; the special lens consists of a middle part, a waist part and an edge part; the curvatures of the middle part, the waist part and the edge part are different; wherein, by controlling the position where the square light spot passes through the special lens and based on the change in the optical path difference of the square light spot passing through different positions of the special lens, the curvatures of the middle part, the waist part and the edge part are dynamically adjusted to compensate for the optical path difference at different positions, thereby reducing the light spot distortion.

10. An optical system for reducing spot distortion, characterized in that: The invention comprises a light spot shaping element and the special lens as claimed in claim 9.

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