阅读说明：本技术 形成点环光斑的光学系统 (Optical system for forming point-ring light spot ) 是由 方笑尘 方强 于 2020-05-29 设计创作，主要内容包括：本发明公开了一种形成点环光斑的光学系统,包括光纤、锥台形光学偏转元件和光学成像系统；所述锥台形光学偏转元件及所述光学成像系统设置在光纤输出光路上,所述光学成像系统设置在锥台形光学偏转元件前侧和/或后侧；所述光纤发出的光经过锥台形光学偏转元件和所述光学成像系统组成的系统后,在某个面上形成一个点环状结构的光斑,本发明能实现各种光斑结构要求的光学系统,同时构成该系统的元件能够采用传统光学加工技术制造,降低了系统的制造难度,从而能够大大降低系统的制造成本。(The invention discloses an optical system for forming a point ring light spot, which comprises an optical fiber, a frustum-shaped optical deflection element and an optical imaging system, wherein the optical fiber is arranged on the optical deflection element; the frustum-shaped optical deflection element and the optical imaging system are arranged on an optical fiber output light path, and the optical imaging system is arranged on the front side and/or the rear side of the frustum-shaped optical deflection element; the invention can realize optical systems with various light spot structure requirements, and elements forming the system can be manufactured by adopting the traditional optical processing technology, thereby reducing the manufacturing difficulty of the system and greatly reducing the manufacturing cost of the system.)

1. An optical system for forming a spot-ring spot, comprising: the optical fiber optical imaging device comprises an optical fiber (1), a frustum-shaped optical deflection element (2) and an optical imaging system (3); the frustum-shaped optical deflection element (2) and the optical imaging system are arranged on an output light path of the optical fiber (1), and the optical imaging system (3) is arranged on the front side and/or the rear side of the frustum-shaped optical deflection element (2); after light emitted by the optical fiber (1) passes through a system consisting of the frustum-shaped optical deflection element (2) and the optical imaging system (3), a light spot with a point annular structure is formed on a certain surface.

2. The optical system for forming a spot ring spot as claimed in claim 1, wherein: when the optical imaging system (3) is arranged on the front side and the rear side of the frustum-shaped optical deflecting element (2), the optical imaging system (3) comprises a first optical imaging subsystem (31) and a second optical imaging subsystem (32), the first optical imaging subsystem (31) is arranged on the front side of the frustum-shaped optical deflecting element (2), and the second optical imaging subsystem (32) is arranged on the rear side of the frustum-shaped optical deflecting element (2).

3. The optical system for forming a spot ring spot as claimed in claim 1, wherein: the frustum-shaped optical deflection element (2) comprises a top surface (21) and a bottom surface (22) which are parallel to each other, the periphery of the top surface (21) is a conical surface, and the bottom surface of the frustum-shaped optical deflection element (2) outputs towards the light source of the optical fiber (1).

4. The optical system for forming a spot ring spot as claimed in claim 1, wherein: the optical deflection device is characterized by further comprising a compound lens (4), wherein the compound lens (4) is arranged close to the frustum-shaped optical deflection element (2), and focal lengths of a central part and peripheral parts of the compound lens (4) are different.

5. The optical system for forming a spot ring spot according to claim 4, wherein: the compound lens (4) is close to the top surface of the frustum-shaped optical deflecting element (2).

6. The optical system for forming a spot ring spot according to claim 4, wherein: the center of the compound lens (4) is a parallel flat plate, and the periphery of the compound lens is provided with positive lenses; or the central part of the compound lens (4) is a negative lens, and the periphery of the compound lens is a parallel flat plate.

7. The optical system for forming a spot ring spot according to claim 4, wherein: the central parts of the two surfaces of the compound lens (4) are planes, and the peripheral parts are convex surfaces one by one and are planes.

8. The optical system for forming a spot ring spot according to claim 4, wherein: one surface of the central part of the two surfaces of the compound lens (4) is a plane, the other surface of the central part of the two surfaces of the compound lens is a concave surface, and the peripheral part of the compound lens is a plane.

9. An optical system for forming a spot-ring spot, comprising: the optical fiber optical deflection lens comprises an optical fiber (1), a frustum-shaped optical deflection lens composite element (5) and an optical imaging system (3); the frustum-shaped optical deflection lens composite element (5) and the optical imaging system (3) are arranged on an output light path of the optical fiber (1), and the optical imaging system (3) is arranged on the front side and/or the rear side of the frustum-shaped optical deflection lens composite element (5); after light emitted by the optical fiber (1) passes through a system consisting of the frustum-shaped optical deflection lens composite element (5) and the optical imaging system (3), a light spot with a point annular structure is formed on a certain surface.

10. The optical system for forming a spot ring spot as claimed in claim 9, wherein: the frustum-shaped optical deflection lens composite element (5) is composed of two parts, one surface of the central part is a plane, the other surface of the central part is a concave spherical surface, so that light penetrating through the frustum-shaped optical deflection lens composite element is diffused, and the peripheral parts of the frustum-shaped optical deflection lens composite element are conical surfaces, so that the light penetrating through the frustum-shaped optical deflection lens composite element is deflected towards the central direction.

Technical Field

The invention belongs to the field of laser processing, and particularly relates to an optical system for forming a spot ring light spot.

Background

Point ring light spots are introduced in the high-power laser processing field, and the technical advantages of material splashing inhibition, preheating slow cooling, better processing efficiency, better processing quality and the like can be achieved by preheating materials around a central working point. At present, there are two main technical approaches for realizing point-ring light spots in the market: the coherent company forms a point light spot at the center and a ring light spot at the edge through a plurality of layers of optical fibers; the published invention of the large family of lasers (CN 206952364U) obtains a spot-ring spot by using an optical system including an optical fiber, a collimating lens, a circular spot focusing lens, a conical lens, and an annular spot focusing lens. Wherein: the former system has high complexity and extremely high price; the optical elements used in the latter, such as a circular spot focusing lens, a conical lens, an annular spot focusing lens and the like, are very complex to process and expensive, and the single lens convergence system with the spot at the central point usually has large aberration. The prior art on the market can not reliably realize point-ring light spots with low cost.

The two technical solutions mainly have the following problems in use:

firstly, in laser processing, structural parameters of spot rings need to be adjusted according to technological requirements, the parameters comprise the size of a central spot, the diameter of the spot rings, the width of the spot rings and the energy distribution of the spot rings, and the enlargement and the reduction of the whole spot, namely system zooming, also need to be realized. Among these requirements, the coherent solution cannot change the structural relationship of the light spot, but can change the size of the light spot by zooming through the optical system. The large group company scheme can change the spot structure, but the system structure cannot provide the zooming capability, and the spot cannot be enlarged or reduced as a whole.

Secondly, the complexity of a solution system of a coherent company is high, and the price is extremely expensive; the optical elements used in the solution of the major companies, such as the circular spot focusing lens, the conical lens and the annular spot focusing lens, are very complicated to process and expensive. In particular, a circular spot focusing lens and a circular cone lens need to be manufactured by free-form surface processing equipment.

The prior art in the market can not meet the requirement of laser processing on spot-ring light spots, and can not provide a system for realizing the spot-ring light spots with low cost and reliability.

Disclosure of Invention

In order to solve the problems in the prior art, the present invention aims to provide an optical system capable of meeting the requirements of various spot structures, and elements constituting the system can be manufactured by using the conventional optical processing technology, so that the manufacturing difficulty of the system is reduced, and the manufacturing cost of the system can be greatly reduced.

In order to achieve the purpose, the invention adopts the technical scheme that the optical system for forming the point ring light spot comprises an optical fiber, a frustum-shaped optical deflection element and an optical imaging system; the frustum-shaped optical deflection element and the optical imaging system are arranged on an optical fiber output light path, and the optical imaging system is arranged on the front side and/or the rear side of the frustum-shaped optical deflection element; after light emitted by the optical fiber passes through a system consisting of the frustum-shaped optical deflection element and the optical imaging system, a light spot with a point annular structure is formed on a certain surface.

Further, when the optical imaging system is disposed on the front side and the rear side of the frustum-shaped optical deflecting element, the optical imaging system includes a first optical imaging subsystem disposed on the front side of the frustum-shaped optical deflecting element and a second optical imaging subsystem disposed on the rear side of the frustum-shaped optical deflecting element.

Further, the frustum-shaped optical deflecting element includes a top surface and a bottom surface which are parallel to each other, the periphery of the top surface is a tapered surface, and the bottom surface of the frustum-shaped optical deflecting element is output toward the light source of the optical fiber.

Furthermore, the optical deflection device also comprises a compound lens, wherein the compound lens is arranged close to the frustum-shaped optical deflection element, and the focal lengths of the central part and the peripheral part of the compound lens are different.

Further, the compound lens is close to the top surface of the frustum-shaped optical deflecting element.

Furthermore, the center part of the compound lens is a parallel flat plate, and the periphery of the compound lens is provided with positive lenses; or the central part of the compound lens is a negative lens, and the periphery of the compound lens is a parallel flat plate.

Furthermore, the central parts of the two surfaces of the compound lens are planes, and the peripheral parts of the compound lens are convex surfaces one by one and are planes.

Furthermore, one surface of the central part of each of the two surfaces of the compound lens is a plane, the other surface of the central part of each of the two surfaces of the compound lens is a concave surface, and the peripheral parts of the central part of each of the two surfaces of the compound lens are planes.

An optical system for forming a point ring light spot comprises an optical fiber, a frustum-shaped optical deflection lens composite element and an optical imaging system; the frustum-shaped optical deflection lens composite element and the optical imaging system are arranged on an optical fiber output light path, and the optical imaging system is arranged on the front side and/or the rear side of the frustum-shaped optical deflection lens composite element; after light emitted by the optical fiber passes through a system consisting of the frustum-shaped optical deflection lens composite element and the optical imaging system, a light spot with a point annular structure is formed on a certain surface.

Furthermore, the frustum-shaped optical deflection lens composite element is composed of two parts, wherein one surface of the central part is a plane, the other surface of the central part is a concave spherical surface, so that light penetrating through the frustum-shaped optical deflection lens composite element is diffused, and the peripheral parts of the central part are conical surfaces, so that the light penetrating through the frustum-shaped optical deflection lens composite element is deflected towards the central direction of the frustum-shaped optical deflection lens composite element.

The invention creatively uses the frustum-shaped optical deflection element to divide the light output by the optical fiber into light which is similar to the light simultaneously emitted from one point ring light source through reasonable system design, and the two beams of light form a real point ring light spot structure on a certain surface behind through a subsequent optical imaging system and are used for laser processing. In order to make the parameters of the light spot structure easier to change so as to meet wider process requirements, a compound lens is added behind the frustum-shaped optical deflection element. Furthermore, we also creatively use the frustum-shaped optical deflection lens composite element to replace the frustum-shaped optical deflection element and the composite lens, so that the system is simpler, and simultaneously, because two working surfaces are reduced, the energy loss is reduced and the stray light generating heat hazard in the system is reduced. Compared with the prior art, the light spot structure has the greatest effect that the light spot structure meeting various process requirements can be realized, which cannot be realized by the prior art. The spot ring spot structure provided by the solution of COHERNT corporation is determined by the structure of the optical fiber, the subsequent system cannot be changed, the solution of the large group corporation can design the spot structure according to the process requirement, but cannot realize the amplification or the requirement of the spot, because the provided central single-lens optical structure has no ability of realizing optical zooming.

In addition, the invention brings another effect that: the used parts are easy to process. For example, in the processing of the frustum-shaped optical deflecting element, a conical surface can be formed by a traditional process, and then the central part of the conical surface is ground into a plane by the traditional process, but the scheme of the central plane and the peripheral conical surface of the major company cannot be processed by traditional equipment. Similarly, the central concave spherical compound lens element adopted by the invention can be manufactured by manufacturing a plano-concave lens by using the traditional process and then grinding the tile surfaces at the periphery, while the central convex spherical lens of a large group company in the background art can not be realized by the traditional manufacturing process. The optical element is simple to process and low in cost, so that the production cost of the system is greatly reduced.

During the laser welding process, the spot-ring light spot generated by the invention heats, melts and sinters the working substances such as metal and the like by the central dot-shaped light spot, the metal is preheated and cleaned in the front half part of the annular light spot, and the welding area can be smoothly and slowly cooled in the rear half part. In laser cutting processing, the annular light spots provide preheating, surface reflection of high-reflection materials is restrained, a laser is protected, and processing efficiency is improved. In the laser cladding process, the central light spot sinters cladding materials and a matrix, and the annular light spot provides preheating and slow cooling, so that the cladding quality is improved.

Drawings

Fig. 1A is a schematic structural diagram of an optical system for forming a spot-ring light spot according to the present invention, in which a frustum-shaped optical deflecting element is located between an optical fiber and the optical system.

Fig. 1B is a schematic diagram of a second structure of the optical system for forming a spot-ring light spot according to the present invention, wherein a frustum-shaped optical deflecting element is located behind the optical system.

Fig. 1C is a schematic diagram of a third structure of the optical system for forming a spot-ring light spot according to the present invention, wherein a frustum-shaped optical deflecting element is located between two optical subsystems of the optical system.

Fig. 2A is a schematic structural diagram of a frustum-shaped optical deflecting element in an optical system for forming a spot ring spot according to the present invention.

Fig. 2B is a schematic position diagram of a frustum-shaped optical deflecting element and a compound lens in the optical system for forming a spot ring spot according to the present invention.

Fig. 3A is a schematic structural diagram of a compound lens in an optical system for forming a spot ring spot according to the present invention.

Fig. 3B is another structural diagram of the compound lens in the optical system for forming a spot ring spot according to the present invention.

Fig. 4 is a schematic optical path diagram of embodiment 1 of the present invention.

Fig. 5 is a schematic diagram of an optical path in embodiment 2 of the present invention.

FIG. 6 is a schematic diagram of a third structure of the present invention, wherein a frustum-shaped optical deflection lens is arranged in front of the optical imaging system.

Fig. 7A and 7B are schematic structural diagrams of two specific frustum-shaped optical deflection lens composite elements, respectively.

FIG. 8 is a schematic structural diagram of embodiment 3 of the present invention,

wherein: 1 is an optical fiber; 2 is a frustum-shaped optical deflection element; 3 is an optical imaging system, 31 is a first optical imaging subsystem, 32 is a second optical imaging subsystem, 3LC is a collimating lens, 3LF is a focusing lens, 3LF1 is a first focusing sub-lens, and 3LF2 is a second focusing sub-lens; 4 is a compound lens; 5 denotes a truncated cone-shaped optical deflection lens complex element, 51 denotes a complex element top surface, 52 denotes a complex element bottom surface, 53 denotes a complex element tapered surface, and 54 denotes a complex element concave spherical surface.

Detailed Description

The optical system for forming a spot ring spot according to the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.

As shown in fig. 2A, the frustum-shaped optical deflecting element 2 of the present invention includes a top surface 21 and a bottom surface 22 which are parallel to each other, the periphery of the top surface 21 is a tapered surface, and the bottom surface of the frustum-shaped optical deflecting element 2 is output toward the light source of the optical fiber 1; as shown in fig. 2A, the frustum-shaped optical deflecting element 2 is composed of two parts, the central part is parallel to the front and rear end faces, so that the light passing through the central part does not change the propagation direction, and the peripheral parts are tapered surfaces to deflect the light passing through it toward the central direction of the frustum-shaped optical deflecting element 2, and in the preferred embodiment of the present invention, the taper angle of the frustum-shaped optical deflecting element 2 is less than 3 °.

As shown in fig. 1A to 1C, the optical system for forming a spot annular light spot according to the present invention includes an optical fiber 1, a frustum-shaped optical deflecting element 2, and an optical imaging system 3. In fig. 1A, a frustum-shaped optical deflecting element 2 is located between an optical fiber 1 and an optical imaging system 3. In fig. 1B, a frustum-shaped optical deflecting element 2 is located behind the optical fiber and the optical imaging system 3. In fig. 1C, the frustum-shaped optical deflecting element 2 is located between the first optical imaging system subsystem 31 and the second optical imaging system subsystem 32, and light emitted from the optical fiber 1 passes through a system formed by the frustum-shaped optical deflecting element 2 and the optical imaging system 3 to form a spot with a point-and-ring structure on a certain surface.

In the optical system for forming a spot annular spot described above, the frustum-shaped optical deflecting element 2 is preferably disposed such that the bottom surface 22 faces the light source.

The operation of the system will be described with reference to the structure shown in fig. 1A. After the light output from the end face of the optical fiber 1 passes through the bottom face 22 of the frustum-shaped optical deflecting element 2, the light at the center portion directly passes through the top face 21 of the frustum-shaped optical deflecting element 2, and the light at the peripheral portions is deflected toward the center by the tapered face of the frustum-shaped optical deflecting element 2. From the viewpoint of imaging, the frustum-shaped optical deflecting element 2 forms a virtual image of the optical fiber end face on the optical fiber end face in the same size, and also forms an annular virtual image around the optical fiber end face. The ring width of the virtual ring image is the same as the diameter of the optical fiber core, and the radius of the ring is equal to the product of the deflection angle generated by the frustum-shaped optical deflection element 2 and the distance from the frustum-shaped optical deflection element 2 to the optical fiber. The deflection angle generated by the frustum-shaped optical deflection element 2 is equal to the product of the angle between the conical surface and the bottom surface of the element and the value obtained by subtracting 1 from the refractive index of the element. After a virtual image generated by the frustum-shaped optical deflection element 2 passes through the optical imaging system, a point ring structured light spot determined by the magnification of the optical imaging system is formed on an image plane. The relative energy distribution of the spot in the spot and the ring spot is determined by the ratio of the sizes of the incident spots on the top surface and the bottom surface of the frustum-shaped optical deflection element 2 and the energy distribution of the incident spots.

In the optical system shown in fig. 1A, 1B, and 1C, after the frustum-shaped optical deflecting element 2 splits the light, the two portions of light pass through the same optical system, and the size of the central spot is the same as the width of the ring spot, and the diameter of the ring spot is mainly controlled by the deflection angle of the frustum-shaped optical deflecting element 2. Also, in this system, by designing the optical imaging system 3 as a zoom optical system, the entire size variation of the spot can be realized.

In another embodiment of the invention, based on the same inventive concept, an improved structure is also provided, which can change the proportional relationship between the spot diameter and the annular spot width, and further expand the application range and the use scene of the spot ring structure of the invention, and the specific scheme is as shown in fig. 2B, a compound lens 4 is added beside the frustum-shaped optical deflection element 2, and the focal lengths of the central part and the peripheral part of the compound lens 4 are different; of course, as a preferred embodiment, the compound lens 4 is disposed behind the frustum-shaped optical deflecting element 2, i.e., the compound lens 4 is disposed close to the top surface 21 of the frustum-shaped optical deflecting element 2, and with this configuration, stray light generated when the compound lens 4 is placed in front of the frustum-shaped optical deflecting element 2 can be avoided.

As a preferred embodiment, a composite lens which is easy to process has a central portion which is a parallel flat plate and peripheral portions which are curved surfaces, or a central portion which is a curved surface and peripheral portions which are flat surfaces.

In one embodiment, the compound lens 4 has the structure shown in fig. 3A, and one surface thereof is a flat surface, and the center of the other surface is a concave spherical surface; in another embodiment, the compound lens 4 has the structure shown in fig. 3B, and one surface of the compound lens 4 is a flat surface, and the edge of the other surface is a convex spherical surface. These two elements are the most easily processed compound lens elements.

In the optical system for forming a spot annular spot described above, the frustum-shaped optical deflecting element 2 is preferably disposed so that the bottom surface faces the light source.

The operation of the system is also illustrated in the configuration shown in fig. 1A, where a compound lens 4 is arranged immediately after the frustum-shaped optical deflection element 2. After the light output from the end face of the optical fiber 1 passes through the bottom face of the frustum-shaped optical deflecting element 2, the light at the central portion directly passes through the top face of the frustum-shaped optical deflecting element 2, and the light at the peripheral portion is deflected toward the central direction by the tapered face of the frustum-shaped optical deflecting element 2. From the viewpoint of imaging, the frustum-shaped optical deflecting element 2 forms a virtual image of the optical fiber end face on the optical fiber end face in the same size, and also forms an annular virtual image around the optical fiber end face. The ring width of the virtual ring image is the same as the diameter of the optical fiber core, and the radius of the ring is equal to the product of the deflection angle generated by the frustum-shaped optical deflection element 2 and the distance from the frustum-shaped optical deflection element 2 to the optical fiber. The deflection angle generated by the frustum-shaped optical deflection element 2 is equal to the product of the angle between the conical surface and the bottom surface of the element and the value obtained by subtracting 1 from the refractive index of the element. Due to the introduction of the compound lens 4, and the power of the central part of the compound lens 4 is different from the power of the peripheral part, it combines with the optical imaging system 3 to form two systems of different powers facing different zones. At this time, the spot light formed by the frustum-shaped optical deflecting element 2 is imaged by the optical system corresponding to the central region, and the annular spot light is imaged by the optical system corresponding to the peripheral region. The two image surfaces are located at different positions, and the working surface can be arranged at a position meeting the light spot requirement according to the actual requirement.

In the optical system for forming the spot-ring structured light spot, because the two parts of light respectively pass through the two independent optical systems after being split by the frustum-shaped optical deflecting element, parameters such as the size of the central light spot, the ring width, the ring diameter and the like of the spot-ring structured light spot generated by the system can be flexibly designed according to the process requirements. The optical imaging system 3 in the system can adopt a zooming structure design to realize the size change of the whole spot of the spot ring. Therefore, based on the technical scheme, the optical processing system meeting the requirements of various laser processing processes can be designed.

The invention also provides another scheme under the same inventive concept.

The invention provides another optical system for forming point annular light spots, which comprises optical fibers, a frustum-shaped optical deflection lens composite element 5 and an optical imaging lens system 3; the frustum-shaped optical deflection lens complex 5 may be located on one side of the optical imaging lens system 3, or may be located between the two subsystems 31 and 32 constituting the optical imaging system 3. The frustum-shaped optical deflection lens composite element consists of two parts, wherein one surface of the central part is a plane, the other surface of the central part is a concave spherical surface, so that light penetrating through the frustum-shaped optical deflection lens composite element is diffused, and the peripheral parts of the central part are conical surfaces, so that the light penetrating through the frustum-shaped optical deflection lens composite element is deflected towards the central direction of the frustum-shaped optical deflection lens composite element; after light emitted by the optical fiber passes through a system consisting of the frustum-shaped optical deflection lens composite element and the optical imaging system, a light spot with a point annular structure is formed on a certain surface.

The frustum-shaped optical deflection lens complex 5 includes a top surface 51, a bottom surface 52, a tapered surface 53, and a concave spherical surface 54, and two specific configurations are shown in fig. 7A and 7B, in which the configuration shown in fig. 7A is preferable, in fig. 7A, the top surface 51 and the bottom surface 52 are disposed opposite to each other, and the concave spherical surface 54 is disposed on the top surface 51, and in fig. 7A, the entire top surface 51 is the concave spherical surface 54, and the tapered surface 53 surrounds the top surface 51. In fig. 7B, the top surface 51 and the bottom surface 52 are arranged to face each other, and the concave spherical surface 54 is provided on the bottom surface 52 at the center of the bottom surface 52 and formed around the top surface 51 at the tapered surface of the tapered surface 53.

Fig. 6 shows a schematic structural diagram of the frustum-shaped optical deflection lens complex element 5 located in front of the optical imaging lens system 3, and we explain the working principle of the frustum-shaped optical deflection lens complex element in this structure. After the light output from the end face of the optical fiber 1 passes through the bottom surface 51 of the frustum-shaped optical deflection lens composite element 5, the light at the central portion passes through the concave spherical surface 52 on the frustum-shaped optical deflection lens composite element 5 and then diverges, and the light at the peripheral portion is deflected toward the central direction by the conical surface 53 of the frustum-shaped optical deflection lens composite element 5, and the deflection angle is related to the angle between the conical surface and the bottom plane. From the viewpoint of imaging, the frustum-shaped optical deflection lens complex element 5 forms a virtual image of the end face of the optical fiber in front of the end face of the optical fiber, and also forms an annular virtual image around the end face of the optical fiber. The ring width of the virtual ring image is the same as the diameter of the optical fiber core, and the radius of the ring is equal to the product of the deflection angle generated by the frustum-shaped optical deflection lens composite element 5 and the distance from the top of the frustum-shaped optical deflection lens composite element 5 to the optical fiber. The deflection angle generated by the frustum-shaped optical deflection complex element 5 is equal to the product of the included angle between the conical surface and the bottom surface of the element and the value obtained by subtracting 1 from the refractive index of the element. After a virtual image generated by the frustum-shaped optical deflection lens composite element 5 passes through the optical imaging system, a point ring structured light spot determined by the magnification of the optical imaging system 3 is formed on an image plane. The relative energy distribution of the spot center and the ring spot is determined by the ratio of the sizes of the incident spots on the top surface and the bottom surface of the frustum-shaped optical deflection lens composite element 5 and the energy distribution of the incident spots.

In the optical system for forming the spot-ring structured light spot, different parts of light emitted by the point light source respectively pass through the two independent optical systems, so that parameters such as the size of the central light spot, the ring width, the ring diameter and the like of the spot-ring structured light spot generated by the system can be flexibly designed according to process requirements. In other embodiments of the present invention, the size of the spot-ring light spot can be changed by adopting a zoom structure design for the optical imaging system 3 in the system. Therefore, based on the technical scheme, an optical processing system meeting the requirements of various laser processing processes can be designed; the optical system of the point-ring-shaped light spot has a plurality of application scenes and has very good popularization and use values.

Example 1, in a specific usage scenario of the present invention, a structure of a point annular light spot is required to be formed: the size of a central light spot is 50 micrometers, the diameter of an annular light spot is 150 micrometers, the width of an annular light spot is 50 micrometers, the energy of the point light spot is 60%, and the energy of the annular light spot is 40%. The diameter of the input optical fiber core is 25 micrometers, and the numerical aperture is 0.06. In this embodiment, a point ring spot optical system is designed according to the structure shown in fig. 4, wherein: the focal length of the collimator lens 3LC is 100 mm; the focal length of the focusing lens 3LF is 100 mm; the frustum-shaped optical deflecting element 2 is made of quartz glass with a refractive index of 1.46, the height is 2 mm, the bottom diameter is 15 mm, the effective clear aperture is 12 mm, according to the characteristics of Gaussian distribution of light beams, the diameter of the top plane part of the frustum-shaped optical deflecting element 2 is 6mm, and the included angle between the peripheral conical surface and the top plane is 0.093 degree. By means of the optical system, a required light spot can be obtained on the back focal plane of the focusing lens.

Example 2, in another specific use scenario of the present invention, the structure required to form a point-annular light spot is: the size of a central light spot is 100 micrometers, the diameter of an annular light spot is 250 micrometers, the width of an annular light spot is 50 micrometers, the energy of the point light spot is 60%, and the energy of the annular light spot is 40%. The diameter of the input optical fiber core is 25 micrometers, and the numerical aperture is 0.06. In this embodiment, a spot ring spot optical system is designed according to the structure shown in fig. 5, wherein: the focal length of the collimating lens 3LC is 50 mm; the focal length of the focusing lens 3LF is 100 mm; the compound lens is a concave spherical surface with one surface being a plane and an effective clear aperture being 6.2 mm, the center of the other surface being a diameter of 3 mm, the periphery being parallel flat plates, the focal length of the central part being-6101.6 mm; the frustum-shaped optical deflecting element 2 is made of quartz glass with the refractive index of 1.46, the height is two millimeters, the bottom is 8 millimeters, the effective clear aperture is 6 millimeters, the diameter of the top plane part is 3 millimeters according to the Gaussian distribution characteristic of light beams, and the included angle of the top planes of the peripheral conical surfaces is 0.1557 degrees. By adopting the above parameter design of the optical system, the required light spot can be obtained on the back focal plane of the focusing lens. The annular light spot is directly imaged on the surface, the focus of the central light beam is behind the surface, and the projection of the central light beam on the surface forms the central light spot.

Example 3, in another specific use scenario of the present invention, the structure required to form a point-annular light spot is: the size of the central light spot is changed from 100 to 300 microns, correspondingly, the diameter of the annular light spot is changed from 200 to 600 microns, the width of the annular light spot is changed from 50 microns to 150 microns, the energy of the point light spot is 60 percent, and the energy of the annular light spot is 40 percent. The diameter of the input optical fiber core is 25 micrometers, and the numerical aperture is 0.06. In this embodiment, a spot ring spot optical system is designed according to the optical path shown in fig. 8, where: the focal length of the collimating lens 3LC is 50 mm; the focusing lens 3LF adopts two lenses to realize zooming design, so that the focal length is changed between 100 mm and 300 mm, wherein the focal length of the first lens 3LF1 is 541.6 mm, the focal length of the second lens 3LF2 is 117.87 mm, and zooming is realized by adjusting the distance between the two lenses; one surface of the frustum-shaped deflection lens composite element 5 facing the light source is a plane, the center of the other surface is a concave spherical surface, the focal length of the frustum-shaped deflection lens composite element is negative 1073.6mm, the frustum-shaped optical deflection lens composite element 5 is made of quartz glass with the refractive index of 1.46, the height of the frustum-shaped optical deflection lens composite element is two millimeters, the bottom of the frustum-shaped optical deflection lens composite element is 8 millimeters, the effective clear aperture is 6 millimeters, according to the characteristics of Gaussian distribution of light beams, the diameter of the top plane part is 3 millimeters, the included angle of the top planes of the peripheral conical surfaces is 0.3278 degrees, and the distance from the bottom surface to the light source is 17.62 millimeters. With this optical system, a desired spot can be obtained on the back focal plane of the focusing lens. The annular light spot is directly imaged on the surface, the focus of the central light beam is behind the surface, and the projection of the central light beam on the surface forms the central light spot.

The technical scheme provided by the invention overcomes the technical defect that the prior technical scheme can not completely meet the structural requirement of the laser processing technology on the spot with the annular structure, and can generate various structural spots meeting the requirement of the laser processing technology. The elements in the optical system designed by the scheme can be processed by adopting the conventional optical processing technology, so that the process requirement is met, and the equipment cost is reduced.