CN113805306A - Optical system with linkage of zoom amount and focusing amount, design method thereof and laser cutting head - Google Patents
Optical system with linkage of zoom amount and focusing amount, design method thereof and laser cutting head Download PDFInfo
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- CN113805306A CN113805306A CN202010478773.6A CN202010478773A CN113805306A CN 113805306 A CN113805306 A CN 113805306A CN 202010478773 A CN202010478773 A CN 202010478773A CN 113805306 A CN113805306 A CN 113805306A
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- 238000003698 laser cutting Methods 0.000 title claims abstract description 36
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- 238000005520 cutting process Methods 0.000 abstract description 14
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
- B23K26/0648—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising lenses
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/38—Removing material by boring or cutting
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/70—Auxiliary operations or equipment
- B23K26/702—Auxiliary equipment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/70—Auxiliary operations or equipment
- B23K26/702—Auxiliary equipment
- B23K26/703—Cooling arrangements
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/0012—Optical design, e.g. procedures, algorithms, optimisation routines
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
- G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
- G02B7/04—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification
Abstract
The invention discloses an optical system for linkage of zoom amount and focusing amount, a design method thereof and a laser cutting head, comprising a lens group consisting of at least two lenses, wherein the lens group is used for imaging an image of a certain object on a certain plane behind the lens group; the invention provides an optical system and a method for changing the zoom amount according to the focusing amount and a laser cutting head, wherein the lens group comprises at least one moving lens, when one moving lens in the lens group is positioned at a certain position, other moving lenses in the lens group are positioned at a specific position corresponding to the certain position, and the invention provides the optical system and the method for changing the zoom amount according to the focusing amount and the laser cutting head: the optical structure of the zoom cutting head is simplified, and the thermal stray light is reduced from the source; the self-lubricating structure is adopted, the heat conduction characteristic of the mechanical structure is greatly improved under the condition of ensuring low friction force, the application requirement is met, the system structure is simplified, the zooming range is enlarged, and the system cost is reduced.
Description
Technical Field
The invention belongs to the technical field of laser processing, and particularly relates to an optical system with a zoom amount and a focusing amount linked, a design method of the optical system and a laser cutting head.
Background
The function of the optical lens is to form an image of an object in space at another position in space, the distance from an object point to an image point is called conjugate distance, and the ratio of the vertical axis size of the image to the vertical axis size of the object is called magnification. At present, people create two types of lenses, one is a fixed focus lens and the other is a zoom lens. For a fixed focus lens in which the positional relationship between optical lenses constituting the lens is fixed, the relationship between the conjugate distance and the magnification is fixed in use, and the flexibility of use of such a lens is limited. For the zoom lens, the positions of some of the optical lenses constituting the lens may be changed, which allows the relationship between the conjugate distance and the magnification to be flexibly combined as needed, providing a strong ability to meet various needs.
In practical application, there is a need that the amplification rate is changed with the conjugate distance according to a certain set rule within a certain conjugate distance change range. For example, in laser cutting processing, the position of a laser spot relative to the surface of a plate needs to be adjusted for different cutting materials and plates with different thicknesses, laser processing equipment needs to adjust the spot at different positions along an optical axis inside and outside a nozzle, the process is called laser focusing, and the focusing process is actually to change conjugate distance; in order to improve the cutting efficiency and the cutting quality, for plates with different thicknesses, laser processing equipment generally needs to change the size of a light spot, the change of the size of the light spot corresponds to the change of a laser convergence angle, the change of the size of the light spot and the change of the convergence angle of the laser convergence angle are opposite, the process is called laser zooming, and the magnification is actually changed in the zooming process. In laser cutting processing, thick plate processing, the facula need set up in the inboard and is close to lower surface department, and the volume of focusing is big, at this moment, should adopt big laser facula, makes laser convergence angle little, can make the joint-cutting narrow, improves cutting efficiency, can make incision face and surface contained angle more be close to 90 degrees simultaneously, improves product quality. That is, in the laser cutting process, a processing spot having a spot size that varies depending on the change in the focusing amount is required. Obviously, there is a need for a device that can change the amount of focus depending on the thickness of the plate according to the characteristics of the cutting process.
For such a requirement, in the prior art, a laser device capable of realizing the linkage of the focusing amount and the zooming amount must have both the zooming and focusing functions. In the existing laser equipment, laser focusing and laser zooming are respectively completed by two sets of optical systems, and the laser equipment has the advantages that various zooming operations can be realized at any focusing point, the laser process requirements can be fully met, the defects are that the system is very complicated, the equipment price is extremely high, and the zooming function is only arranged in a top-level laser cutting machine generally.
The optical aspects of this situation are mainly due to:
1. from an optical system point of view, it is extremely expensive. Besides the complicated design of zoom lenses, aspheric mirrors are often used in large quantities to reduce the number of lenses and ensure image quality, for example: the national engineering research center of Huazhong university of science and technology, Gejiaqi et al (2 nd 2019 of the Chinese optical science) provides a lens design of 7 lenses, and 3 aspherical mirrors are adopted in the design; shanghai Jiaqiang automation technology company provides a technical scheme of 4 lenses (Chinese patent application number CN201510566726.6), and 3 aspheric lenses are adopted. Due to the difficulty in processing the aspherical mirror, the laser lens is very expensive.
2. Because the optical glass material has material absorption and scattering, the light absorbed by the lens directly causes the temperature rise of the lens, and the scattered light is used as stray light to heat devices and a shell in a closed cavity of the optical system. In order to reduce the thermal lens effect caused by the temperature rise caused by the absorption of the material, expensive high-purity glass material is adopted.
3. The level of scattered light of the current high-power film is not less than 0.2% due to the imperfect coating technology of the optical lens, which means that the stray light generated by each single glass lens is not less than 0.4%, and obviously, the increase of the number of glass lenses in the optical system means the increase of the stray light generating heat. For example, if the laser power is ten thousand watts and the heating stray light generated by each lens is 40 watts, an optical system composed of 7 lenses needs at least one protective glass, and the power of the heating stray light in the optical system is at least 320 watts. In order to remove the heat from these parasitic lights, the cooling system must be carefully designed, which can reduce the reliability of the optical system if the cooling effect is not good.
The mechanical reasons for this situation are mainly:
1. the mechanical structure and method for realizing the relative movement of the lenses in the zoom lens are as follows: the lenses are fixed on respective lens frames, the lens frames are connected with the guide rail by the linear bearing, and then the lenses are driven to realize relative motion by the cam erected on the bearing, so that the aim of zooming is achieved. The specific structure can be seen in the technical scheme disclosed in Chinese patent application No. 201910637898.6. In a laser optical system, due to absorption and scattering of a lens material and light scattering caused by imperfect coating on a lens surface, the temperature of a lens and a lens frame sealed in a cam can be increased, the heat conduction characteristic of a linear bearing is poor, heat on the lens and the lens frame can be transferred to the cam only through air, the cam can also generate heat under the action of light, part of heat on the cam is transferred to a base through the bearing, and the other part of heat is transferred through air.
2. The conventional structure either limits the power of the zoom lens due to poor heat dissipation, or causes poor reliability of the optical system when used with high power, and in severe cases, causes performance degradation, such as thermal lens effect.
3. This configuration also results in a mechanical system that is complex, difficult to install, and large in size.
4. In addition, the zoom range of the current general zoom lens is usually relatively small, and the system complexity is further increased to increase the zoom range.
Disclosure of Invention
In order to solve the problems in the prior art, the invention aims to provide an optical system with linked zooming amount and focusing amount, a design method thereof and a laser cutting head, which can simplify the system structure, increase the zooming range and reduce the system cost while meeting the application requirements.
In order to achieve the above object, the present invention adopts a technical solution that an optical system with linked zooming amount and focusing amount comprises a lens group composed of at least two lenses, wherein the lens group is used for imaging an image of an object on a certain plane behind the lens group; the lens group comprises at least one moving lens, and when one moving lens in the lens group is located at a certain position, other moving lenses in the lens group are located at a specific position corresponding to the position.
Further, when the moving lens in the lens group is adjusted to a certain position, two parameters of conjugate distance and magnification of the lens group are uniquely determined.
The invention also provides a design method of the optical system, which designs the position change rule of the lens in the lens group and specifically comprises the following steps:
step 1) determining conjugate distances and corresponding magnifications of a plurality of points in a focusing range according to focusing and zooming motion rules provided by technical requirements;
step 2) calculating and determining the positions of the lenses in the lens group required by the conjugate distance and the magnification at each point by using optical design through the conjugate distance and the corresponding magnification at the plurality of points obtained in the step 1);
and 3) summarizing the position change of each moving lens obtained by calculation in the step 2), and fitting to obtain a motion rule function of each moving lens.
The invention also provides a laser cutting head based on the optical system, which comprises a sleeve, a cam and the optical system, wherein the optical system comprises at least two lenses, each lens is respectively fixed on one lens frame, all the lens frames are arranged in the sleeve and can slide along the axial direction of the sleeve, and a sliding groove is formed in the wall of the sleeve along the direction parallel to the axial direction of the sleeve;
the cam sleeve is arranged on the sleeve, control grooves which correspond to the slidable lens frames one to one are formed in the cam, the control grooves are not parallel to the sliding grooves, intersection parts are formed between each control groove and the sliding grooves to form control structures, the intersection parts correspond to the lens frames one to one, each lens frame is connected with a driving lever through the corresponding intersection parts, the driving lever is driven to slide and move in the sliding grooves through a rotating cam, the lens frames are driven to move in the sleeve, and the linkage of zooming and focusing is achieved.
Furthermore, the sliding grooves formed in the sleeve correspond to the slidable lens frames one to one.
Further, a self-lubricating structure is arranged between the outer surface of the lens frame and the inner surface of the sleeve, and the self-lubricating structure is arranged on the outer surface of the lens frame and/or the inner surface of the sleeve; at least one of the inner surface of the cam and the outer surface of the sleeve has a self-lubricating structure.
Further, the lens frame is made of a self-lubricating material, or the lens frame is composed of a lens frame base body and a self-lubricating coating on the outer surface of the base body, or is composed of a lens frame base body and a self-lubricating material embedded on the lens frame base body; the outer surface of the sleeve is provided with a self-lubricating structure; the sleeve consists of a sleeve substrate and a self-lubricating coating on the outer surface of the substrate, or the sleeve consists of a sleeve substrate and a self-lubricating material embedded on the sleeve substrate; the sleeve base body is made of a metal material.
The invention also provides a laser cutting head based on the optical system, which comprises a sleeve, the optical system and a lens frame, wherein the lens frame comprises a first lens frame and a second lens frame; a sliding groove is formed in the wall of the sleeve along the direction parallel to the axis of the sleeve, one end of the shifting rod penetrates through the sliding groove to be fixedly connected with the second lens frame, and the shifting rod is dragged to drive the second lens frame and the second lens to move in the sleeve, so that the linkage of the zooming amount and the focusing amount is realized.
Further, a self-lubricating structure is arranged between the outer surface of the lens frame and the inner surface of the sleeve, and the self-lubricating structure is arranged on the outer surface of the lens frame and/or the inner surface of the sleeve.
Further, the second lens frame is made of a self-lubricating material, or is composed of a lens frame base body and a self-lubricating coating on the outer surface of the base body, or is composed of a lens frame base body and a self-lubricating material embedded on the lens frame base body.
Compared with the prior art, the invention has at least the following beneficial effects:
the invention provides an optical system with linked zooming and focusing amounts, wherein two parameters of conjugate distance and magnification of a lens group are designed within a certain range and realized by position change in the lens group, the conjugate distance is changed by adjusting the position of at least one lens in the lens group, for example, imaging moves along the optical axis direction, focusing is realized in laser processing, the size of the imaging is changed (namely zooming) while focusing is carried out, and the two parameters of the conjugate distance and the magnification of the lens group correspond to each other when a moving lens in the lens group is adjusted to a certain position.
The laser cutting head provided by the invention can realize focusing and zooming linkage operation simultaneously only by being driven by one motor, thereby simplifying the system structure and increasing the zooming range; moreover, according to actual use requirements, the structure of the optical system of the zoom and focus cutting head can be simplified to be only two, the structure design is reasonable, and the heat stray light can be reduced from the source.
Furthermore, the laser head of the invention widely adopts a self-lubricating structure, the self-lubricating structure is preferably graphite, and the graphite is used as a good heat conducting material, so that the heat conducting property of a mechanical structure can be greatly improved under the condition of ensuring low friction force, in the design, the self-lubricating structure realizes surface contact between devices, the heat conducting property is greatly improved, the working power of the laser cutting head can be improved along with the great improvement of the heat problem, and the service life of the laser cutting head is prolonged; in addition, the laser cutting head is reasonable in structural design, and the cost of the laser cutting head for zooming and focusing can be greatly reduced.
Drawings
Fig. 1 is a schematic diagram of an optical system with linked zooming and focusing amounts according to the present invention.
Fig. 2 is a schematic structural diagram of a first laser cutting head based on the linkage of the zoom amount and the focus amount of two lenses according to the present invention.
Fig. 3 is a schematic structural diagram of a second laser cutting head based on the linkage of the zoom amount and the focus amount of three lenses according to the present invention.
Fig. 4 is a schematic structural diagram of a third laser cutting head based on the linkage of the zoom amount and the focus amount of two lenses according to the present invention.
Wherein: 2G1 and 2G2 denote predetermined lenses, 21 denotes a first optical lens, 22 denotes a second optical lens, and 23 denotes a third optical lens; 31 denotes a first lens frame, 32 denotes a second lens frame, and 33 denotes a third lens frame; 51 denotes a first stick, 52 denotes a second stick, and 53 denotes a third stick; 6 denotes a sleeve; and 7 denotes a cam.
Detailed Description
The optical system, method and laser cutting head for linking the zoom amount and the focus amount according to the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.
Fig. 1 is a schematic diagram of an optical system with linked zooming and focusing amounts according to the present invention. The lens group constituting the optical system includes at least two lenses, at least one of which is movable along the axial direction, and usually includes a plurality of fixed lenses, such as the fixed lenses 2G1 and 2G2 shown in fig. 1, although there may be more fixed lenses according to actual needs, and a plurality of moving lenses, such as the first optical lens 21 and the second optical lens 22 shown in fig. 1, which are both moving lenses in this embodiment, and of course, there may be more moving lenses according to actual needs. The system images something on a certain face behind it. The system is different from the traditional fixed-focus lens, and the conjugate distance and the magnification of the traditional fixed-focus lens are fixed and cannot be flexibly designed. The system is designed to generate images of a specific size for different target points (conjugate distances). The conventional zoom system of this system differs in that it can produce a series of images of different sizes for one target point (conjugate distance).
The method for realizing the linkage of the zoom amount and the focusing amount by the system comprises the following steps: by adjusting the position of at least one lens in the lens group, the conjugate distance is changed (the image moves along the optical axis direction, and focusing is performed during laser processing), and the size of the image is changed (zooming is performed); the position change rule of the lens in the lens group is determined by the following method: 1) determining conjugate distances and corresponding amplification rates of a plurality of points in a focusing range according to focusing and zooming motion rules provided by technical requirements; 2) determining the positions of the lenses in the lens group by optical design calculation; 3) and taking out the positions of the moving lenses to obtain the motion law functions of the moving lenses.
Fig. 2 is a schematic structural diagram of a laser cutting head based on the linkage of the zoom amount and the focus amount of two lenses according to the present invention. The lens comprises a first optical lens 21, a second optical lens 22, a first lens frame 31, a second lens frame 32, a first shift lever 51, a second shift lever 52, a sleeve 6 and a cam 7. Wherein: the first optical lens 21 is fixed on the first lens frame 31, and the second optical lens 22 is fixed on the second lens frame 32; two sliding grooves are formed in the wall of the sleeve 6 along the direction parallel to the axis of the sleeve 6; a first lens frame 31 and a second lens frame 32 are provided inside the ferrule 6 near one end; at least one of the outer surface of the first lens frame 31 and the inner surface of the sleeve 6 has a self-lubricating structure, and at least one of the outer surface of the second lens frame 32 and the inner surface of the sleeve 6 has a self-lubricating structure; the cam 7 is sleeved on the outer surface of the sleeve, at least one surface of the inner surface of the cam 7 and the outer surface of the sleeve 6 is provided with a self-lubricating structure, the cam 7 is provided with control grooves corresponding to the first lens frame 31 and the second lens frame 32 one by one, the control grooves are not parallel to the sliding grooves, a junction is formed between each control groove and each sliding groove to form a control structure, the junctions correspond to the first lens frame 31 and the second lens frame 32 one by one, and the first lens frame 31 and the second lens frame 32 are connected with a first driving lever 51 and a second driving lever 52 through the junctions corresponding to the first lens frame 31 and the second lens frame 32. In the cutting head with the linkage of the zoom amount and the focusing amount, the cam 7 rotates and drags the first poking rod 51 and the second poking rod 52 to drive the first lens frame 31 and the second lens frame 32 and the first optical lens 21 and the second optical lens 22 fixed on the lens frames to realize the linkage of the zoom amount and the focusing amount of the optical system.
In the above system, the self-lubricating structure is generally made on the outer annular surface of the lens frame, which is more convenient. The first lens frame 31 and the second lens frame 32 may be made of a self-lubricating material, may be composed of an annular lens frame base and a self-lubricating coating on the outer surface of the base, and may be composed of an annular lens frame base and a self-lubricating material embedded in the annular lens frame base.
In the above systems, the external surface of the sleeve 6 is generally provided with a self-lubricating structure; the sleeve 6 can be composed of a sleeve substrate and a self-lubricating coating on the outer surface of the substrate, and the sleeve 6 can also be composed of a sleeve substrate and a self-lubricating material embedded on the sleeve substrate. The base body of the sleeve 6 is made of a metallic material.
Fig. 3 is a schematic structural view of a laser cutting head based on the linkage of the zoom amount and the focus amount of three lenses according to the present invention. The lens comprises a first optical lens 21, a second optical lens 22, a third optical lens 23, a first lens frame 31, a second lens frame 32, a third lens frame 33, a first shift lever 51, a second shift lever 52, a third shift lever 53, a sleeve 6 and a cam 7. Wherein: the first optical lens 21 is fixed on the first lens frame 31, the second optical lens 22 is fixed on the second lens frame 32, and the third optical lens 23 is fixed on the first lens frame 33; three sliding grooves are formed in the wall of the sleeve 6 along the direction parallel to the axis of the sleeve 6; the first lens frame 31, the second lens frame 32 and the third lens frame 33 are sequentially arranged in the sleeve 6; at least one of the outer surface of the first lens frame 31 and the inner surface of the sleeve 6 has a self-lubricating structure, at least one of the outer surface of the second lens frame 32 and the inner surface of the sleeve 6 has a self-lubricating structure, and at least one of the outer surface of the third lens frame 33 and the inner surface of the sleeve 6 has a self-lubricating structure; the cam 7 is sleeved on the outer surface of the sleeve 6, at least one of the inner surface of the cam 7 and the outer surface of the sleeve 6 is provided with a self-lubricating structure, the cam 7 is provided with control grooves which are in one-to-one correspondence with the first lens frame 31, the second lens frame 32 and the third lens frame 33, the control grooves are not parallel to the sliding grooves, intersections are formed between each control groove and the sliding groove to form the control structure, and the intersections are in one-to-one correspondence with the first lens frame 31, the second lens frame 32 and the third lens frame 33; the first lens frame 31, the second lens frame 32, and the third lens frame 33 are connected to a first shift lever 51, a second shift lever 52, and a third shift lever 53 at their corresponding intersections. In the cutting head with the linkage of the zoom amount and the focus amount, the first toggle lever 51, the second toggle lever 52 and the third toggle lever 53 are dragged by the rotating cam 7 to drive the first lens frame 31, the second lens frame 32 and the third lens frame 33 as well as the first optical lens 21, the second optical lens 22 and the third optical lens 23 which are fixed on the lens frames, so that the linkage of the zoom amount and the focus amount of the optical system is realized.
In the above system, the self-lubricating structure is generally made on the outer annular surface of the lens frame, which is more convenient. The first lens frame 31, the second lens frame 32 and the third lens frame 33 may be made of a self-lubricating material, may be composed of an annular lens frame base and a self-lubricating coating on the outer surface of the base, and may be composed of an annular lens frame base and a self-lubricating material embedded on the annular lens frame base.
In the above systems, the external surface of the sleeve 6 is generally provided with a self-lubricating structure; the sleeve 6 can be composed of a sleeve substrate and a self-lubricating coating on the outer surface of the substrate, and the sleeve 6 can also be composed of a sleeve substrate and a self-lubricating material embedded on the sleeve substrate. The base body of the sleeve 6 is made of a metallic material.
Fig. 4 is a schematic structural diagram of a laser cutting head based on the linkage of the zoom amount and the focus amount of two lenses according to the present invention. The lens comprises a first optical lens 21, a second optical lens 22, a first lens frame 31, a second lens frame 32, a second deflector rod 52 and a sleeve 6. Wherein: the first optical lens 21 is fixed on the first lens frame 31, and the second optical lens 22 is fixed on the second lens frame 32; a first lens frame 31 with a sliding groove is arranged on the wall of the sleeve 6 along the direction parallel to the axis of the sleeve 6 and is fixedly arranged in the sleeve 6 and close to one end of the sleeve 6; the second lens frame 32 is arranged in the casing 6, close to the other end of the casing 6; at least one of the outer surface of the second lens frame 32 and the inner surface of the ferrule 6 has a self-lubricating structure; the second lens frame 32 is connected to a second shift lever 52 through a slide groove in the ferrule 6. In the cutting head with the linkage of the zoom amount and the focus amount, the second lens frame 32 and the second optical lens 22 fixed on the second lens frame 32 are driven by dragging to the second driving lever 52, so that the linkage of the zoom amount and the focus amount of the optical system is realized.
The system has a simpler structure than the system shown in fig. 2, but has much lower design flexibility and is suitable for low-requirement application occasions.
In the above system, the self-lubricating structure is generally made on the outer annular surface of the lens frame, which is more convenient. The lens frame 32 may be made of a self-lubricating material, or may be composed of an annular lens frame base and a self-lubricating coating on the outer surface of the base, or may be composed of an annular lens frame base and a self-lubricating material embedded in the annular lens frame base.
According to the technical scheme shown in FIG. 2, a laser cutting head for a single-mode laser based on the linkage of the zoom amount and the focusing amount of two lenses is designed. The cutting head is suitable for laser output with a numerical aperture of 0.065, and can change the core diameter of a laser output optical fiber from 2 times to 5 times. Wherein, the two lenses both adopt spherical mirrors, and the focal lengths are respectively 34.71 mm and 45.48 mm; the lens frames 31 and 32 are structured by embedding a self-lubricating material (graphite) in a metal base, and the lenses are fixed inside the lens frames. The outer surface of the sleeve 6 is provided with a self-lubricating structure, and the sleeve is made of a metal matrix embedded with a self-lubricating material (graphite). The designed change rule of the processing light spot is as follows: focusing amount is 5 mm, and magnification is 2 times; focusing amount is 0 mm, and magnification is 2 times; the focusing amount is minus 5 mm, and the magnification is 3 times; the focusing amount is minus 10 mm, and the magnification is 4 times; the focusing amount is minus 15 times and the magnification is 5 times. Compared with the traditional zoom and focus system: 1) only two spherical lenses are needed, so that the thermal stray light and the cost of an optical system can be greatly reduced; 2) the method can be realized by only one set of motion driving mechanism, so that the cost of the motor, the sensor and the driving mechanism is greatly reduced; 3) the zoom range is large, and if the zoom lens is adopted, the zoom range with the same structure can only be 2 to 4 times.
According to the technical scheme shown in FIG. 3, a laser cutting head for a multimode laser based on the linkage of the zoom amount and the focusing amount of three lenses is designed. The cutting head is suitable for laser output with numerical aperture of 0.1 core diameter, and can change the core diameter of the laser output optical fiber from 1.2 times to 3 times. Wherein, the three lenses all adopt spherical mirrors, and the focal lengths are respectively 87 mm, 100.48 mm and 100.93 mm; the lens frames 31, 32 and 33 are constructed by embedding a self-lubricating material (graphite) in a metal substrate, and the lenses are fixed inside the lens frames. The outer surface of the sleeve 6 is provided with a self-lubricating structure, and the sleeve is made of a metal matrix embedded with a self-lubricating material (graphite). The designed change rule of the processing light spot is as follows: focusing amount is 15 mm, and magnification is 1.2 times; focusing amount is 10 mm, and magnification is 1.2 times; focusing amount is 5 mm, and magnification is 1.2 times; focusing amount is 0 mm, and magnification is 1.2 times; the focusing amount is minus 5 mm, and the magnification is 1.75 times; the focusing amount is minus 10 mm, and the magnification is 2 times; the focusing amount is minus 15, and the magnification is 2.25 times; the focusing amount is minus 20, and the magnification is 2.5 times; the focusing amount is minus 25, and the magnification is 2.75 times; the focusing amount is minus 30 and the magnification is 3 times. Compared with the traditional zoom and focus system: 1) only three spherical lenses (at least four lenses and three aspheric lenses are adopted in the existing scheme) are needed, so that the cost of the thermal stray light and the optical system can be greatly reduced, and the reduction of the thermal stray light is beneficial to improving the reliability of the system; 2) the method can be realized by only one set of motion driving mechanism, so that the cost of the motor, the sensor and the driving mechanism is greatly reduced; 3) the zooming range is enlarged, and the magnification of the zoom lens with the same structure can only be 1.2 to 2.2 times.
According to the technical scheme shown in FIG. 4, a laser cutting head for a single-mode laser based on the linkage of the zoom amount and the focusing amount of two lenses is designed. The cutting head is suitable for laser output with a numerical aperture of 0.065, and can change the core diameter of a laser output optical fiber from 2 times to 5 times. Wherein, the two lenses both adopt spherical mirrors, and the focal lengths are respectively 34.7 mm and 45.48 mm; the lens frame 32 is made of metal base material (graphite) and the lens is fixed inside the lens frame. The designed change rule of the processing light spot is as follows: the focusing amount is 4.5 mm, and the magnification is 3 times; focusing amount is 0 mm, and magnification is 3.5 times; the focusing amount is minus 5 mm, and the magnification is 3 times; the focusing amount is minus 10 mm, and the magnification is 4 times; the focusing amount is minus 18.2, and the magnification is 5 times. Compared with the scheme provided by the embodiment 1, the scheme has the advantages of poor design flexibility, small zoom range and relatively simple structure.
The optical system, the method and the laser cutting head for linkage of the zoom amount and the focusing amount are optimally designed according to the characteristics of a laser cutting process, have simple structure compared with the existing automatic focusing automatic zooming scheme, and can be realized by adopting a set of driving device; the optical system uses the spherical lens, so that the cost is greatly reduced, and the reduction of the number of the lens of the optical system reduces the heat stray light, thereby being beneficial to improving the reliability of the system.
Claims (9)
1. An optical system for linking a zoom amount and a focus amount, comprising: the lens group comprises at least two lenses and is used for imaging an image of an object on a certain plane behind the lens group; the lens group comprises at least one moving lens, and when one moving lens in the lens group is located at a certain position, other moving lenses in the lens group are located at a specific position corresponding to the position.
2. The zoom amount-focus amount-linked optical system according to claim 1, wherein: when the moving lens in the lens group is adjusted to a certain position, two parameters of conjugate distance and magnification of the lens group are uniquely determined.
3. A method of designing an optical system according to claim 1 or 2, characterized by: the method for designing the position change rule of the lens in the lens group specifically comprises the following steps:
step 1) determining conjugate distances and corresponding magnifications of a plurality of points in a focusing range according to focusing and zooming motion rules provided by technical requirements;
step 2) calculating and determining the positions of the lenses in the lens group required by the conjugate distance and the magnification at each point by using optical design through the conjugate distance and the corresponding magnification at the plurality of points obtained in the step 1);
and 3) summarizing the position change of each moving lens obtained by calculation in the step 2), and fitting to obtain a motion rule function of each moving lens.
4. A laser cutting head based on the optical system of claim 1 or 2, characterized in that: the optical lens system comprises a sleeve (6), a cam (7) and an optical system, wherein the optical system comprises at least two lenses, each lens is fixed on one lens frame, all the lens frames are arranged in the sleeve and can slide along the axial direction of the sleeve, and a sliding groove is formed in the wall of the sleeve (6) along the direction parallel to the axial direction of the sleeve (6);
cam (7) cover is established on sleeve pipe (6), it has the control flume with slidable lens frame one-to-one to open on cam (7), control flume and sliding tray nonparallel, and all there is the intersection to form control structure between every control flume and the sliding tray, intersection and lens frame one-to-one, every lens frame all is connected with a driving lever through the intersection rather than corresponding, through rotatory cam (7), drive the driving lever at sliding tray sliding movement, drive the lens frame and remove in sleeve pipe (6), realize zooming volume and the linkage of focusing the volume.
5. The laser cutting head of claim 4, wherein: a self-lubricating structure is arranged between the outer surface of the lens frame and the inner surface of the sleeve (6), and the self-lubricating structure is arranged on the outer surface of the lens frame and/or the inner surface of the sleeve (6); at least one of the inner surface of the cam and the outer surface of the sleeve (6) has a self-lubricating structure.
6. The laser cutting head of claim 4, wherein: the lens frame is made of a self-lubricating material, or the lens frame is composed of a lens frame base body and a self-lubricating coating on the outer surface of the base body, or the lens frame base body and the self-lubricating material embedded on the lens frame base body; the outer surface of the sleeve (6) is provided with a self-lubricating structure; the sleeve (6) consists of a sleeve substrate and a self-lubricating coating on the outer surface of the substrate, or the sleeve (6) consists of a sleeve substrate and a self-lubricating material embedded on the sleeve substrate; the sleeve base body is made of a metal material.
7. A laser cutting head based on the optical system of claim 1 or 2, characterized in that: the optical lens comprises a sleeve, an optical system and a lens frame, wherein the lens frame comprises a first lens frame (31) and a second lens frame (32), the optical system comprises a first optical lens (21) and a second optical lens (22), the first optical lens (21) is fixed on the first lens frame (31), the first lens frame (31) is fixed in the sleeve (6), the second optical lens (22) is fixed on the second lens frame (32), and the second lens frame (32) is arranged in the sleeve (6) and can slide along the axial direction of the sleeve (6); a sliding groove is formed in the wall of the sleeve (6) in the direction parallel to the axis of the sleeve (6), one end of a shifting lever penetrates through the sliding groove to be fixedly connected with the second lens frame (32), and the shifting lever is dragged to drive the second lens frame (32) and the second lens (22) to move in the sleeve (6), so that the linkage of the zooming amount and the focusing amount is realized.
8. The laser cutting head of claim 7, wherein: and a self-lubricating structure is arranged between the outer surface of the lens frame and the inner surface of the sleeve (6), and the self-lubricating structure is arranged on the outer surface of the lens frame and/or the inner surface of the sleeve (6).
9. The laser cutting head of claim 7, wherein: the second lens frame (32) is made of a self-lubricating material, or consists of a lens frame base body and a self-lubricating coating on the outer surface of the base body, or consists of a lens frame base body and a self-lubricating material embedded on the lens frame base body.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
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| CN202010478773.6A CN113805306A (en) | 2020-05-29 | 2020-05-29 | Optical system with linkage of zoom amount and focusing amount, design method thereof and laser cutting head |
| PCT/CN2021/097537 WO2021239153A1 (en) | 2020-05-29 | 2021-05-31 | Zooming amount and focusing amount linked optical system, design method therefor, and laser cutting head thereof |
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| CN202010478773.6A CN113805306A (en) | 2020-05-29 | 2020-05-29 | Optical system with linkage of zoom amount and focusing amount, design method thereof and laser cutting head |
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| CN113805306A true CN113805306A (en) | 2021-12-17 |
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| WO (1) | WO2021239153A1 (en) |
Cited By (1)
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| CN116577900A (en) * | 2023-07-13 | 2023-08-11 | 中国科学院长春光学精密机械与物理研究所 | Photoelectric imaging system with allele focal length adjustment function |
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| CN111168230B (en) * | 2020-03-04 | 2022-03-04 | 济南邦德激光股份有限公司 | Focusing device and focusing method of laser cutting machine |
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| WO2021239153A1 (en) | 2021-12-02 |
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