Optical system and processing method for realizing adjustable taper processing of microholes

Abstract

The present invention provides an optical system for realizing micro-hole taper adjustable processing, comprising a laser beam shaping unit, a laser beam deflection unit and a focusing unit arranged in sequence along the optical path, wherein the laser beam shaping unit, the laser beam deflection unit and the focusing unit are located on the same central axis; the laser beam deflection unit comprises a deflection lens, the end face of the beam incident end of the deflection lens is a planar structure, the end face of the beam exit end thereof is a conical surface, and the generatrix of the conical surface is at a certain angle to the end face of the beam incident end of the deflection lens; the relative distance between the focusing unit and the laser beam deflection unit is adjustable. In addition, the present invention also provides a micro-hole processing method using the above optical system. The invention obtains a ring-shaped laser beam with energy distribution at the edge through the cooperation between various optical elements, which can meet the processing requirements of micro-holes with different apertures and tapers, and effectively solves the problem that the existing ring-shaped spot radius is small in adjustment and difficult to meet different processing requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of laser processing, and in particular relates to an optical system and a processing method for realizing micro-hole taper adjustable processing. Background Art

[0002] Laser drilling is widely used in many fields. How to make the holes meet the required aperture and achieve the desired taper is the main issue that needs to be considered in laser drilling. The current mainstream drilling method is rotary cutting, which uses an optical device to deflect the laser and then rotates it to achieve drilling. The laser beam used is mainly Gaussian distribution, and the energy is concentrated in the center area. In the fields of laser welding, laser drilling, laser cutting and other processing fields, Gaussian beams cannot meet all processing needs. When processing deep holes and cutting materials with too short a focal depth, large tapers and bevels will appear. The energy in the edge area of ​​the Gaussian distribution laser beam is weak, but it will still affect the processing material. Heat accumulation will occur when processing materials, which will cause burrs on the processing edge and severe burning.

[0003] The use of annular light spots can effectively solve this problem. Compared with the Gaussian distribution of laser beams, the energy of annular light spots is evenly distributed at the edge, which can effectively avoid the uneven processing edge caused by insufficient edge energy. The existing technologies for generating annular light spots mainly include generating combined annular light spots based on computational holography. In principle, computational holography can be designed to generate any light spot including a combined annular light spot. However, since computational holography generally uses off-axis first-order diffraction light, coupled with factors such as loss, the light energy utilization rate is low, so it is relatively less used; the other method is to use a laser with an adjustable light spot mode based on optical fiber to generate a combined annular light spot. This method has great difficulty and cost in adjusting the light spot distribution mode in the optical fiber. Since there is no adjustable external optical path, it lacks flexibility and convenience in use. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem in the prior art that the adjustment of the annular spot distribution pattern is difficult and costly, and it is difficult to meet different processing requirements.

[0005] To this end, the present invention provides an optical system for realizing micro-hole taper adjustable processing, comprising a laser beam shaping unit, a laser beam deflection unit and a focusing unit arranged in sequence along the optical path, wherein:

[0006] The laser beam shaping unit, the laser beam deflection unit and the focusing unit are located on the same central axis, and the laser beam is incident along the central axis;

[0007] The laser beam shaping unit is used to shape the laser beam, converting the incident parallel beam into a convergent or divergent beam, thereby changing the size of the output light spot;

[0008] The laser beam deflection unit comprises a deflection lens, the end face of the beam incident end of the deflection lens is a plane structure, the end face of the beam emitting end of the deflection lens is a conical surface, and the rotation axis of the conical surface coincides with the center of the laser beam shaped by the laser beam shaping unit, and the generatrix of the conical surface forms a certain angle with the end face of the beam incident end of the deflection lens; the laser beam shaped by the laser beam shaping unit is incident from the plane end face of the deflection lens, and after being deflected by the conical surface, the energy of the laser beam becomes annular distribution and has a certain deflection angle;

[0009] The focusing unit is used to focus the annular laser beam to obtain an annular light spot with concentrated energy; the relative distance between the focusing unit and the laser beam deflection unit is adjustable.

[0010] Furthermore, a laser is arranged before the laser beam shaping unit, and the laser emits a parallel laser beam with a Gaussian distribution of light intensity. A reflecting mirror is also arranged between the laser and the laser beam shaping unit for making the laser beam emitted by the laser enter along the central axis of the laser beam shaping unit, and the center of the laser beam coincides with the central axis of the laser beam shaping unit.

[0011] Furthermore, the laser beam shaping unit includes a fixed first focusing mirror and a second focusing mirror that can move back and forth along the optical path, and the first focusing mirror and the second focusing mirror are located on the same central axis.

[0012] Furthermore, the deflection lens is composed of a combination of a lens 1 with a cylindrical structure and a lens 2 with a conical structure, and the conical bottom surface of the lens 2 coincides with the cylindrical bottom surface of the lens 1.

[0013] Furthermore, the focusing unit includes a lens group for use with it.

[0014] In addition, the present invention also provides a micro-hole processing method using the above optical system, comprising the following process:

[0015] S1. Arrange the optical paths of a laser beam shaping unit, a laser beam deflection unit and a focusing unit in sequence, and the laser beam shaping unit, the laser beam deflection unit and the focusing unit are located on the same central axis, and the laser beam is incident along the central axis; wherein the laser beam shaping unit comprises a fixed first focusing mirror and a second focusing mirror that can move back and forth along the optical path direction; the laser beam deflection unit comprises a deflection lens, the end face of the beam incident end of the deflection lens is a planar structure, the end face of the beam exit end thereof is a conical surface, and the rotation axis of the conical surface coincides with the center of the laser beam shaped by the laser beam shaping unit, and the generatrix of the conical surface is arranged at a certain angle to the end face of the beam incident end of the deflection lens;

[0016] S2, coarsely adjusting the processed micro-hole aperture by controlling the angle between the cone surface generatrix of the deflection lens in the laser beam deflection unit and the end face of the beam incident end of the deflection lens, and finely adjusting the processed micro-hole aperture by adjusting the relative distance between the first focusing mirror and the second focusing mirror in the laser beam shaping unit, so that the micro-hole aperture meets the processing requirements;

[0017] S3. The taper of the processed micro-hole is adjusted by controlling the relative distance between the laser beam deflection unit and the focusing unit to meet the processing requirements of micro-holes with different tapers.

[0018] Specifically, the method for coarse adjustment of the micro-aperture diameter is as follows: the larger the angle between the conical surface generatrix of the deflection lens and the end face of the light beam incident end of the deflection lens, the greater the light beam deflection, and the larger the annular spot output by the focusing unit, thereby making the processed micro-aperture diameter larger; conversely, the smaller the angle between the conical surface generatrix of the deflection lens and the end face of the light beam incident end of the deflection lens, the smaller the processed micro-aperture diameter becomes.

[0019] Specifically, the method of fine-tuning the micropore aperture is as follows: the focal lengths of the first focusing mirror and the second focusing mirror are f1 and f2 respectively, and the relative distance d between the first focusing mirror and the second focusing mirror is controlled by moving the position of the second focusing mirror. When d<f1+f2, the light spot will increase as d decreases, and when d>f1+f2, the light spot will decrease as d increases.

[0020] Specifically, the adjustment method of the microhole taper is as follows: when the relative distance between the laser beam deflection unit and the focusing unit becomes larger, the processed microhole will form a processing surface with a positive taper; when the relative distance between the laser beam deflection unit and the focusing unit becomes smaller, the processed microhole will form a processing surface with a negative taper; when the relative distance between the laser beam deflection unit and the focusing unit is at a critical point, the processed microhole will form a processing surface without taper.

[0021] Specifically, the relative distance between the first focusing mirror and the second focusing mirror, and the relative distance between the laser beam deflection unit and the focusing unit are adjusted manually, or automatically by a wirelessly controlled electric control system with a power supply.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The optical system provided by the present invention for realizing adjustable micro-hole taper processing outputs an annular light spot, and the energy is evenly distributed on the annular light spot at the focal length of the focusing unit. Compared with directly using a laser beam with a Gaussian light intensity distribution for processing, the energy of the annular light spot is evenly distributed around the ring, and the energy at the edge area is the strongest, which will not cause the problem of affecting the flatness of the material processing surface due to weak energy at the edge.

[0024] (2) The optical system provided by the present invention for realizing adjustable taper processing of microholes uses a ring-shaped spot to synchronously process the ring diameter of the microhole. The time required is relatively short. Moreover, the energy of the ring-shaped spot is dispersed around the ring, and the power of a single point is relatively small. This can effectively avoid the phenomenon of edge collapse, excessive heat reaction at the edge of the back hole, black edges, etc. caused by high power when a Gaussian distributed laser beam is used to directly perform hole processing on the workpiece. At the same time, the power of the laser beam used is further increased, which can further shorten the processing time.

[0025] (3) The aperture of the microhole processed by the optical system for realizing adjustable microhole taper processing provided by the present invention is coarsely adjusted by a laser beam deflection unit and finely adjusted by a laser beam shaping unit. The adjustable range is wide and the adjustable accuracy is high. The taper of the microhole is determined by the relative distance between the laser beam deflection unit and the focusing unit. The processing requirements of microholes with various tapers can be met, which effectively solves the problem in the prior art that the radius of the annular spot is small and difficult to meet different processing requirements.

[0026] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic structural diagram of an optical system for realizing micro-hole taper adjustable processing in an embodiment of the present invention;

[0028] Figure 2 is a schematic structural diagram of a deflection lens in an embodiment of the present invention;

[0029] Figure 3 Schematic diagram of the structure of the change of the aperture of the micropores processed in the embodiment of the present invention;

[0030] Figure 4 It is a structural schematic diagram of the change in taper of the microhole processed in an embodiment of the present invention.

[0031] Explanation of the accompanying drawings: 1. laser beam; 2. first focusing mirror; 3. second focusing mirror; 4. laser beam deflection unit; 5. focusing unit; 6. lens one; 7. lens two. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0034] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0035] like Figure 1 As shown, this embodiment provides an optical system for realizing adjustable taper processing of microholes, including a laser beam shaping unit, a laser beam deflection unit 4 and a focusing unit 5 arranged in sequence along the optical path, wherein the laser beam shaping unit, the laser beam deflection unit 4 and the focusing unit 5 are located on the same central axis, and the laser beam 1 is incident along the central axis, and the center of the laser beam 1 coincides with the center of the central axis of the optical system.

[0036] The laser beam shaping unit is used to shape the laser beam 1, and change the incident parallel beam into a convergent or divergent beam, thereby changing the size of the output light spot. Specifically, the laser beam shaping unit includes a fixed first focusing mirror 2 and a second focusing mirror 3 that can move back and forth along the optical path direction, and the first focusing mirror 2 and the second focusing mirror 3 are located on the same central axis, so that the center of the laser beam 1 incident is located on the central axis of the laser beam shaping unit; and the diameter of the output light spot can be fine-tuned by adjusting the position of the second focusing mirror 3 in the laser beam shaping unit. Specifically, the focal lengths of the first focusing mirror 2 and the second focusing mirror 3 are f1 and f2 respectively, and the relative distance d between the first focusing mirror 2 and the second focusing mirror 3 is controlled by moving the position of the second focusing mirror 3. When d<f1+f2, a laser beam that converges inward at a small angle is output, and the laser beam 1 is evenly divided by the laser beam deflection unit 4. The energy of the laser beam 1 is evenly distributed in a ring shape, and the energy is converged by the focusing unit 5 to obtain an annular light spot. At the same time, the output annular light spot will increase as d decreases, and when d>f1+f2, the output annular light spot will decrease as d increases.

[0037] The position of the second focusing mirror 3 in the laser beam shaping unit can be adjusted manually or automatically by using a wirelessly controlled electric control system with a power supply.

[0038] The laser beam deflection unit 4 is used to deflect the beam shaped by the laser beam shaping unit, so as to obtain a laser beam whose energy is annular and converges toward the center at a certain angle. Specifically, the laser beam deflection unit 4 includes a deflection lens, the beam incident end face of the deflection lens is a plane structure, and the beam exit end face is a conical surface, and the rotation axis of the conical surface coincides with the center of the laser beam shaped by the laser beam shaping unit, and the generatrix of the conical surface is at a certain angle to the beam incident end face of the deflection lens; the laser beam shaped by the laser beam shaping unit is incident from the plane end face of the deflection lens, and the divergent or convergent laser beam output by the laser beam shaping unit is deflected and split by the conical surface to become a convergent laser beam, and the energy of the laser beam is converted into an annular distribution, wherein the shape and manufacturing material of the conical surface are different, and the output annular spot mode and spot size are also different.

[0039] A specific implementation method, such as Figure 2 As shown, the deflection lens is composed of a lens 1 6 with a cylindrical structure and a lens 2 7 with a conical structure, and the conical bottom surface of the lens 2 6 coincides with the cylindrical bottom surface of the lens 1 6. The output annular spot diameter can be roughly adjusted by adjusting the angular relationship between the conical surface and the conical bottom surface of the lens 2 7 with a conical structure; specifically, the larger the angle formed by the conical surface generatrix of the deflection lens and the end face of the light beam incident end of the deflection lens, the greater the light beam deflection, and the larger the annular spot output by the focusing unit, thereby increasing the aperture of the processed microhole; conversely, the smaller the angle formed by the conical surface generatrix of the deflection lens and the end face of the light beam incident end of the deflection lens, the smaller the aperture of the processed microhole.

[0040] like Figure 3 As shown, the processed micro-hole aperture is roughly adjusted by controlling the angle between the cone surface generatrix of the deflection lens in the laser beam deflection unit 4 and the end face of the beam incident end of the deflection lens, and the processed micro-hole aperture is finely adjusted by adjusting the relative distance between the first focusing mirror 2 and the second focusing mirror 3 in the laser beam shaping unit, so that the micro-hole aperture meets the processing requirements, has a wide adjustable range, and has high adjustable accuracy.

[0041] The focusing unit 5 is used to focus the annular laser beam to obtain an annular light spot with concentrated energy. The focusing unit 5 includes a lens group used in conjunction with the focusing unit 5. The relative distance between the focusing unit 5 and the laser beam deflection unit 4 is adjustable, and the relative distance will affect the taper of the micro-hole processing surface. By controlling the relative distance between the laser beam deflection unit 4 and the focusing unit 5, the taper of the processed micro-hole is adjusted to meet the micro-hole processing requirements of different tapers. Specifically, Figure 4As shown, when the relative distance between the laser beam deflection unit 4 and the focusing unit 5 increases, the processed microhole will form a processing surface with a positive taper, and when the relative distance between the laser beam deflection unit 4 and the focusing unit 5 decreases, the processed microhole will form a processing surface with a negative taper. When the relative distance between the laser beam deflection unit 4 and the focusing unit 5 is at a critical point, the processed microhole will form a processing surface without taper, and the critical point position can be obtained through debugging.

[0042] The change of the relative distance between the laser beam deflection unit 4 and the focusing unit 5 is mainly achieved by adjusting the position of the laser beam deflection unit 4. The adjustment of the position of the laser beam deflection unit 4 can be achieved manually or automatically by using a wirelessly controlled electric control system with a power supply.

[0043] When the relative distance between the first focusing mirror 2 and the second focusing mirror 3, and the relative distance between the laser beam deflection unit 4 and the focusing unit 5 are automatically adjusted by a wirelessly controlled electric control system with a power supply, the aperture and taper can be controlled in real time during the micro-hole processing process, and micro-holes with complex structures can be processed, thereby expanding its application range.

[0044] In a further optimized implementation, a laser is arranged before the laser beam shaping unit, and the laser emits a parallel laser beam with a Gaussian distribution of light intensity. A reflecting mirror is also arranged between the laser and the laser beam shaping unit for causing the laser beam emitted by the laser to be incident along the central axis of the laser beam shaping unit, and the center of the laser beam coincides with the central axis of the laser beam shaping unit.

[0045] In summary, the optical system for realizing adjustable taper processing of microholes provided by the present invention obtains an annular laser beam with energy distributed at the edge through the combination of various optical elements, which can be directly used for micro circular hole processing, anisotropic hole processing and cutting. At the same time, by controlling the relative position relationship of the laser beam shaping unit, the laser beam deflection unit and the focusing unit, it can meet the processing requirements of microholes with different apertures and tapers, effectively solving the problem in the prior art that the radius of the annular spot is small and difficult to meet different processing requirements, and has a wide adjustable range and high adjustable accuracy.

[0046] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. An optical system for realizing micro-hole taper adjustable processing, characterized in that: It includes a laser beam shaping unit, a laser beam deflection unit and a focusing unit which are arranged in sequence along the optical path, wherein: The laser beam shaping unit, the laser beam deflection unit and the focusing unit are located on the same central axis, and the laser beam is incident along the central axis; The laser beam shaping unit is used to shape the laser beam, and change the incident parallel beam into a convergent or divergent beam, so as to change the size of the output light spot; the laser beam shaping unit includes a fixed first focusing mirror and a second focusing mirror that can move back and forth along the light path direction, and the first focusing mirror and the second focusing mirror are located on the same central axis; The laser beam deflection unit comprises a deflection lens, the end face of the beam incident end of the deflection lens is a plane structure, the end face of the beam emitting end of the deflection lens is a conical surface, and the rotation axis of the conical surface coincides with the center of the laser beam shaped by the laser beam shaping unit, and the generatrix of the conical surface forms a certain angle with the end face of the beam incident end of the deflection lens; the laser beam shaped by the laser beam shaping unit is incident from the plane end face of the deflection lens, and after being deflected by the conical surface, the energy of the laser beam becomes annular distribution and has a certain deflection angle; The focusing unit is used to focus the annular laser beam to obtain an annular light spot with concentrated energy; the relative distance between the focusing unit and the laser beam deflection unit is adjustable; the focusing unit includes a lens group used in conjunction with it.

2. An optical system for realizing micro-hole taper adjustable processing according to claim 1, characterized in that: A laser is also arranged before the laser beam shaping unit. The laser emits a parallel laser beam with a Gaussian distribution of light intensity. A reflecting mirror is also arranged between the laser and the laser beam shaping unit to make the laser beam emitted by the laser enter along the central axis of the laser beam shaping unit. The center of the laser beam coincides with the central axis of the laser beam shaping unit.

3. An optical system for realizing micro-hole taper adjustable processing according to claim 1, characterized in that: The deflection lens is composed of a first lens with a cylindrical structure and a second lens with a conical structure, and the conical bottom surface of the second lens coincides with the cylindrical bottom surface of the first lens.

4. A micro-hole processing method using an optical system as claimed in any one of claims 1 to 3, characterized in that: The process includes the following: S1. Arrange the optical paths of a laser beam shaping unit, a laser beam deflection unit and a focusing unit in sequence, and the laser beam shaping unit, the laser beam deflection unit and the focusing unit are located on the same central axis, and the laser beam is incident along the central axis; wherein the laser beam shaping unit comprises a fixed first focusing mirror and a second focusing mirror that can move back and forth along the optical path direction; the laser beam deflection unit comprises a deflection lens, the end face of the beam incident end of the deflection lens is a planar structure, the end face of the beam exit end thereof is a conical surface, and the rotation axis of the conical surface coincides with the center of the laser beam shaped by the laser beam shaping unit, and the generatrix of the conical surface is arranged at a certain angle to the end face of the beam incident end of the deflection lens; S2, coarsely adjusting the processed micro-hole aperture by controlling the angle between the cone surface generatrix of the deflection lens in the laser beam deflection unit and the end face of the beam incident end of the deflection lens, and finely adjusting the processed micro-hole aperture by adjusting the relative distance between the first focusing mirror and the second focusing mirror in the laser beam shaping unit, so that the micro-hole aperture meets the processing requirements; S3. The taper of the processed micro-hole is adjusted by controlling the relative distance between the laser beam deflection unit and the focusing unit to meet the processing requirements of micro-holes with different tapers.

5. The micro-hole processing method according to claim 4, characterized in that: The method of coarse adjustment of the micro-aperture diameter is as follows: the larger the angle between the conical surface generatrix of the deflection lens and the end face of the light beam incident end of the deflection lens, the greater the light beam deflection, and the larger the annular spot output by the focusing unit, thereby making the processed micro-aperture diameter larger; conversely, the smaller the angle between the conical surface generatrix of the deflection lens and the end face of the light beam incident end of the deflection lens, the smaller the processed micro-aperture diameter becomes.

6. The micro-hole processing method according to claim 4, characterized in that: The method for fine-tuning the micropore aperture is as follows: the focal lengths of the first focusing mirror and the second focusing mirror are f1 and f2 respectively, and the relative distance d between the first focusing mirror and the second focusing mirror is controlled by moving the position of the second focusing mirror. When d<f1+f2, the light spot will increase as d decreases, and when d>f1+f2, the light spot will decrease as d increases.

7. The micro-hole processing method according to claim 4, characterized in that: The adjustment method of the microhole taper is as follows: when the relative distance between the laser beam deflection unit and the focusing unit becomes larger, the processed microhole will form a processing surface with a positive taper; when the relative distance between the laser beam deflection unit and the focusing unit becomes smaller, the processed microhole will form a processing surface with a negative taper; when the relative distance between the laser beam deflection unit and the focusing unit is at a critical point, the processed microhole will form a processing surface without taper.

8. The micro-hole processing method according to claim 4, characterized in that: The relative distance between the first focusing mirror and the second focusing mirror, and the relative distance between the laser beam deflection unit and the focusing unit are adjusted manually or automatically by a wirelessly controlled electric control system with a power supply.

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