CN213276097U

CN213276097U - Zoom optical system and laser cutting head that focus volume linkage

Info

Publication number: CN213276097U
Application number: CN202020963314.2U
Authority: CN
Inventors: 方强; 方笑尘
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-05-29
Filing date: 2020-05-29
Publication date: 2021-05-25
Anticipated expiration: 2030-05-29

Abstract

The utility model discloses an optical system and laser cutting head that zoom and focus amount linkage, simplify the system architecture when satisfying the application requirement, increase the range of zooming, reduce system cost specifically includes the battery of lens that at least two lens are constituteed, the battery of lens is used for imaging the image of a certain object on certain plane behind it; 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. The utility model simplifies the optical structure of the zoom cutting head and reduces the heat stray light from the source; and a self-lubricating structure is adopted, so that the heat conduction characteristic of the mechanical structure is greatly improved under the condition of ensuring low friction force.

Description

Zoom optical system and laser cutting head that focus volume linkage

Technical Field

The utility model belongs to the technical field of laser beam machining, especially, relate to an optical system and laser cutting head that zooms and focus linkage of volume.

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.

SUMMERY OF THE UTILITY MODEL

In order to solve the problem that exists among the prior art, the utility model aims to provide an optical system and laser cutting head of the linkage of the volume of focusing zoom simplifies the system architecture when satisfying the application requirement, increases the scope of zooming, reduce system cost.

In order to achieve the above object, the present invention adopts a technical solution that an optical system for linking a zoom amount and a focus amount comprises a lens assembly composed of at least two lenses, wherein the lens assembly is used for imaging an image of an object on a certain plane behind the lens assembly; 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 utility model provides an optical system's design method, including designing the position change law of lens in the battery of lens, specifically include following step:

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 utility model also provides a laser cutting head based on above-mentioned optical system, including sleeve pipe, cam and optical system, optical system includes two piece at least lens, and each lens is fixed respectively on a lens frame, and all lens frames all set up in the sleeve pipe and can slide along the sleeve pipe axis direction, wherein, open along being on a parallel with the sleeve pipe axis direction on the sleeve pipe wall has the sliding tray;

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 utility model also provides a laser cutting head based on above-mentioned optical system, including sleeve pipe, optical system and lens frame, the lens frame includes first lens frame and second lens frame, optical system includes first optical lens and second optical lens, first optical lens fixes on first lens frame, and first lens frame fixes in the sleeve pipe, second optical lens fixes on the second lens frame, and the second lens frame sets up in the sleeve pipe and can slide along the sleeve pipe axis direction; 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 utility model discloses following beneficial effect has at least:

the utility model provides an optical system of the linkage of the amount of focusing of zooming designs two parameters of conjugate distance and magnification of the battery of lens in a certain scope to position change through in the battery of lens realizes, through the position of an at least piece lens in the adjustment battery of lens, makes the conjugate distance change, for example the formation of image along the optical axis direction removal, focuses promptly in laser processing, when focusing, still accompanies the change of the size of formation of image (zoom promptly), and, when will when moving lens in the battery of lens adjusts to a certain position, two parameters of conjugate distance and magnification of the battery of lens correspond.

The laser cutting head provided by the utility model can realize the focusing and zooming linkage operation simultaneously only by using one motor to drive, thereby simplifying the system structure and increasing the zooming range; and, according to the user demand of reality, the utility model discloses can realize zooming and focus cutting head optical system's structure and simplify to only two, reasonable structural design can reduce hot miscellaneous light from the source.

Furthermore, the laser head of the utility model widely adopts a self-lubricating structure, the self-lubricating structure preferably adopts graphite, and as a good heat conducting material, the heat conducting property of the mechanical structure can be greatly improved under the condition of ensuring low friction force, and in the design, the self-lubricating structure realizes surface contact between devices, the improved heat conducting property is greatly improved, along with the great improvement of the heat problem, the working power of the laser cutting head can be improved, and the service life of the laser cutting head is prolonged; additionally, the utility model has the advantages of reasonable design, can reduce by a wide margin and zoom the cost of focusing the laser cutting head.

Drawings

Fig. 1 is a schematic diagram of an optical system for linking a zoom amount and a focus amount according to the present invention.

Fig. 2 is the utility model provides a first laser cutting head structure sketch map based on the linkage of the volume of zooming of two lens.

Fig. 3 is a second schematic view of a laser cutting head structure based on the zoom amount and focus amount linkage of three lenses.

Fig. 4 is a schematic structural view of a third laser cutting head based on the zoom amount and focus amount linkage of two lenses.

Wherein: 2G1, 2G2 denote fixed 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 for linking a zoom amount and a focus amount 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 the utility model provides a volume of zooming based on two lenses focuses laser cutting head structure sketch map of linkage of volume. 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 the utility model provides a zoom amount and focus amount linkage's laser cutting head structure sketch map based on three lens. 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.

Fig. 4 is the utility model provides a zoom amount based on two lenses and focus laser cutting head structure sketch map of volume linkage. 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 a metal substrate with a self-lubricating material (preferably graphite) embedded therein, 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 the linkage of the zoom amount and the focusing amount are optimally designed according to the characteristics of the laser cutting process, have simple structure compared with the prior 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

1. An optical system for linking zoom and focusing amount is characterized in that: 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 the moving lenses are two or more than two, when a certain moving lens in the lens group is positioned at a certain position, other moving lenses in the lens group are positioned at positions corresponding to the certain position.

2. The zoom and focus amount linked optical system according to claim 1, wherein: when a 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 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.

4. The laser cutting head of claim 3, 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.

5. The laser cutting head of claim 3, 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.

6. 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 optical lens (22) to move in the sleeve (6), so that the linkage of the zooming amount and the focusing amount is realized.

7. The laser cutting head of claim 6, 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).

8. The laser cutting head of claim 6, 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.