Processing device based on Bessel optics

Abstract

The invention relates to the technical field of laser processing, in particular to a processing device based on Bessel optics. Comprising a main body, the main body is provided with a diaphragm adjusting module, an axicon module, a reflection module and an objective lens module, the objective lens module is arranged on an exit port at the lower end of the main body, and the diaphragm adjusting module, the axicon module, the reflection module and the objective lens module are sequentially arranged along a processing light path; the main body is provided with a coaxial camera, a semi-reflecting and semi-transmitting mirror module and a light source module, and the coaxial camera is arranged at the upper end of the main body, so that the coaxial camera, the semi-reflecting and semi-transmitting mirror module and the objective lens module are sequentially arranged; the light source module and the semi-reflecting and semi-transmitting mirror module are arranged in a paired mode. The structure is reasonable, the length of a light path is compressed and processed through the reflection module, the overall layout is more compact, and the equipment size is reduced; based on the adjustable diaphragm module, the debugging difficulty is reduced, the cutting and micropore machining quality is improved, the machining focus information of the transparent material is obtained, and the laser focus of the transparent material is monitored and compensated in real time.

Description

Technical Field

[0001] The invention relates to the technical field of laser processing, and in particular to a processing device based on Bessel optics. Background Art

[0002] In the process of laser precision manufacturing, the cutting and drilling of transparent and brittle materials such as glass, sapphire and quartz usually adopts a diffraction-free Bessel optical path transmission system. It combines ultrafast laser pulses with beam expansion, axicon and objective lens to convert the incident Gaussian energy into Bessel optical energy distribution, realizing an optical system with a long axial focal depth after focusing. Compared with Gaussian energy distribution, the focused Bessel optics has the advantages of long axial focal depth and concentrated energy distribution, which is very suitable for high aspect ratio cutting and micro-hole manufacturing.

[0003] Unlike Gaussian optical systems, Bessel optical systems are more complex and more sensitive to the transmission stability of the optical path. For example, the Bessel processing head needs to move at high speed, and the stability of the optical path under high-speed dynamic motion conditions directly determines the processing quality. High-precision processing has high requirements on the consistency and symmetry of the Bessel processing beam and the positioning accuracy of the equipment itself.

[0004] The traditional laser coaxial vision system determines whether the processing system is at the laser focus height by observing the surface features of the processed product. It is difficult to obtain the surface information of transparent products to determine the laser focus height. However, Bessel processing equipment is generally used to process transparent products and bare chip products. There are no visible features on the surface, or the features (such as product edges) are far away from the processing position. Therefore, Bessel processing equipment generally uses paraxial vision positioning, but paraxial vision has problems such as a large field of view, low single-pixel accuracy, and a long movement distance after using paraxial vision positioning, resulting in a large linear motor movement repeatability error. It cannot meet the positioning accuracy requirements of high-end precision processing.

[0005] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0006] The purpose of the present invention is to provide a processing device based on Bessel optics with reasonable structure, compact layout, convenient debugging and high precision in view of the defects and shortcomings of the prior art.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention discloses a processing device based on Bessel optics, comprising a main body, on which an aperture adjustment module, an axicon module, a reflection module and an objective lens module are provided, the objective lens module is arranged on the exit port at the lower end of the main body, and the aperture adjustment module, the axicon module, the reflection module and the objective lens module are arranged in sequence along the processing light path; the main body is provided with a coaxial camera, a half-reflective half-mirror module and a light source module, the coaxial camera is arranged at the upper end of the main body and is arranged in sequence with the half-reflective half-mirror module and the objective lens module; the light source module is arranged on one side of the main body, and the light source module is arranged in pairs with the half-reflective half-mirror module.

[0009] According to the above scheme, the aperture adjustment module includes an incident aperture and an aperture adjustment seat. The aperture adjustment seat is fixedly arranged at the incident port at the upper end of the main body. The incident aperture is cooperatively connected with the aperture adjustment seat. A two-dimensional fine adjustment structure is provided on the aperture adjustment seat.

[0010] According to the above solution, a cover plate is provided on the opening on one side of the aperture adjustment seat.

[0011] According to the above scheme, the main body is provided with a first aperture and a second aperture, and the incident aperture, the first aperture, the axicon module and the second aperture are sequentially arranged in the center along the processing optical path.

[0012] According to the above scheme, a phase delay plate is also included, the first aperture is fixedly arranged in the main body through a mounting frame, and the phase delay plate can replace the first aperture and be arranged on the mounting frame.

[0013] According to the above scheme, the reflection module includes a first reflector and a second reflector, and the second aperture, the first reflector, the second reflector and the objective lens module are arranged in sequence along the processing light path, and a third aperture is provided between the first reflector and the second reflector.

[0014] According to the above scheme, the axicon module includes a fixing frame, an axicon mirror and a convex lens, the fixing frame is fixedly connected to the main body, and a first lens barrel and a second lens barrel are provided on the fixing frame; a first fixing member is provided on the first lens barrel, and the first fixing member is connected with the first lens barrel so as to fix the axicon mirror in the first lens barrel; a second fixing member is provided on the second lens barrel, and the second fixing member is connected with the second lens barrel so as to fix the convex lens in the second lens barrel.

[0015] According to the above scheme, the light source module includes a lamp tube, a point light source is provided in the upper port of the lamp tube, a light source reflector is provided in the lower port of the lamp tube, and the lower end of the lamp tube is connected to the main body so that the light source reflector is paired with the semi-reflective and semi-mirror module.

[0016] According to the above scheme, a target tube is provided between the lower end of the lamp tube and the main body, and a first lens, a target sheet and a second lens are sequentially provided in the target tube, and the first lens and the second lens are conjugate lenses.

[0017] According to the above scheme, a camera adjustment seat is provided at the upper end of the main body, the coaxial camera is mounted on the camera adjustment seat, and a two-dimensional fine adjustment structure is provided on the camera adjustment seat.

[0018] The beneficial effects of the present invention are as follows: the present invention has a reasonable structure, and compresses the length of the processing light path through the reflection module, making the overall layout more compact and thus reducing the size of the equipment; based on the adjustable aperture module, the debugging difficulty is reduced, and the quality of cutting and micro-hole processing is improved; it is equipped with a coaxial camera and a light source module to realize the acquisition of processing focus information of transparent materials without surface features, and can realize real-time monitoring and compensation of the laser focus of transparent materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the internal structure of the main body of the present invention;

[0020] Figure 2 It is a structural schematic diagram of the aperture adjustment module of the present invention;

[0021] Figure 3 is a schematic cross-sectional structural diagram of an axicon module of the present invention;

[0022] Figure 4 It is a schematic cross-sectional structure diagram of a light source module of the present invention.

[0023] In the figure:

[0024] 1. Main body; 2. Axicon module; 3. Objective lens module; 4. Coaxial camera; 5. Entrance aperture; 6. Lamp tube; 11. Half-reflective half-mirror module; 12. First reflector; 13. Second reflector; 21. Phase delay plate; 22. Fixing frame; 23. Axicon lens; 24. Convex lens; 25. First lens barrel; 26. Second lens barrel; 27. First fixing piece; 28. Second fixing piece; 41. Camera adjustment seat; 51. Aperture adjustment seat; 52. Cover plate; 53. First aperture; 54. Second aperture; 55. Mounting frame; 56. Third aperture; 61. Point light source; 62. Light source reflector; 63. Target barrel; 64. First lens; 65. Target sheet; 66. Second lens. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is described below in conjunction with the accompanying drawings and embodiments.

[0026] like Figure 1-4As shown, a processing device based on Bessel optics described in the present invention includes a main body 1, on which an aperture adjustment module, an axicon module 2, a reflection module and an objective lens module 3 are provided, and the objective lens module 3 is arranged on the exit at the lower end of the main body 1, and the aperture adjustment module, the axicon module 2, the reflection module and the objective lens module 3 are arranged in sequence along the processing light path; the main body 1 is provided with a coaxial camera 4, a semi-reflective and semi-mirror module 11 and a light source module, and the coaxial camera 4 is arranged at the upper end of the main body 1 so as to be arranged in sequence with the semi-reflective and semi-mirror module 11 and the objective lens module 3; the light source module is arranged on one side of the main body 1, and the light source module is paired with the semi-reflective and semi-mirror module 11.

[0027] The axicon module 2, the reflection module and the objective lens module 3 form a Bessel shaping optical path, which can be used for cutting and hole-making of transparent materials. The preferred processing optical path of the present invention is provided with a reflection module, which changes the linear layout of the traditional optical design, compresses the height of the processing optical path, reduces the overall height of the processing device, and thus saves space and equipment costs.

[0028] Specifically, the reflection module includes a first reflector 12 and a second reflector 13, both of which are 45° reflectors, so that the processing light path turns twice, compressing the overall height without changing the optical distance between the axis pyramid module 2 (core optical element) and the objective lens module 3.

[0029] Furthermore, the light beam generated by the light source module is projected onto the product processing surface through the objective lens module 3. After being reflected, the light beam passes through the objective lens module 3 to form an image for the coaxial camera 4, thereby acquiring the focus information of the objective lens module 3 and the surface feature information of the product.

[0030] Furthermore, the aperture adjustment module, the axicon module 2, the reflection module and the objective lens module 3 constitute a processing optical path, and the coaxial camera 4 is coaxially arranged with the objective lens module 3. The coaxial camera 4 can obtain the surface features of the product at the processing position through the field of view of the objective lens module 3, thereby realizing coaxial visual positioning. The field of view of the objective lens module 3 is generally 0.2-3mm, and the high-precision coaxial camera 4 can achieve a single pixel accuracy of 0.1μm level, and after positioning by the coaxial camera 4, processing within the current position range can avoid the travel error caused by the long-distance movement of the processing platform, thereby realizing high-precision positioning processing.

[0031] It is understandable that the main body 1 is made by an integrated molding process, so that the installation position of each component inside can be more precise. The main body 1 is installed on the connecting plate of the equipment lifting shaft through a number of foot fixing blocks. The laser is arranged above the main body 1. The laser enters from the incident port at the upper end of the main body 1 through the aperture adjustment module, and is emitted from the objective lens module 3 after passing through the components on the processing light path, and processes the product on the processing platform below. The axicon module 2 can convert the laser into a Bessel telephoto depth distribution laser to form micropores or modified areas on the product.

[0032] The aperture adjustment module includes an incident aperture 5 and an aperture adjustment seat 51. The aperture adjustment seat 51 is fixedly arranged at the incident port at the upper end of the main body 1. The incident aperture 5 is connected with the aperture adjustment seat 51. A two-dimensional fine adjustment structure is provided on the aperture adjustment seat 51. The incident aperture 5 can block the external stray light and intercept the more complete part of the Gaussian distribution to enter the axis pyramid module 2 to reduce the edge distortion of the laser beam after shaping. The aperture adjustment seat 51 can be adjusted by a two-dimensional fine adjustment structure, and the two dimensions refer to the X-axis and Y-axis perpendicular to the laser conduction direction. After the external optical path adjustment is completed, the incident aperture 5 is adjusted to be aligned with the incident optical path, which provides a basis for the subsequent judgment of whether the external optical path is offset and the spot size changes.

[0033] It can be understood that the aperture adjustment seat 51 is a hollow structure, and a cover plate 52 is provided on the opening on one side of the aperture adjustment seat 51. By opening the cover plate 52, a frequency doubling plate can be placed in the aperture adjustment seat 51 to observe the size of the infrared laser spot, the energy distribution, and whether the spot is consistent with the aperture center.

[0034] The main body 1 is provided with a first aperture 53 and a second aperture 54, and the incident aperture 5, the first aperture 53, the axicon module 2 and the second aperture 54 are sequentially arranged in a central position along the processing optical path. The incident aperture 5, the first aperture 53 and the second aperture 54 form a three-point-one-line layout along the processing optical path. After the first aperture 53 and the second aperture 54 are centered, the incident aperture 5 and the axicon module 2 are located on the processing optical path, thereby ensuring that the laser beam passes through the axicon module 2 vertically and in the center.

[0035] The present invention further includes a phase delay plate 21, and the first aperture 53 is fixedly arranged in the main body 1 through a mounting frame 55. The phase delay plate 21 can replace the first aperture 53 and be arranged on the mounting frame 55. After the external optical path is adjusted, the laser can pass through the first aperture 53 and the second aperture 54 in the center according to the designed spot size, and then the first aperture 53 is replaced by the phase delay plate 21. The phase delay plate 21 cooperates with the axicon module 2 to shape the Gaussian laser (Bessel shaping) into an elliptical Bessel beam, and finally focuses through the objective lens module 3 to form the required Bessel processing beam.

[0036] The reflection module includes a first reflector 12 and a second reflector 13, and a second aperture 54, a first reflector 12, a second reflector 13 and an objective lens module 3 are sequentially arranged along the processing optical path, and a third aperture 56 is arranged between the first reflector 12 and the second reflector 13. After the adjustment of the first reflector 12 and the second reflector 13 is completed, the third aperture 56 is aligned with the optical path between the two, which can be used to subsequently observe whether there is a deviation in the processing optical path inside the main body 1. It can be understood that the first reflector 12 and the second reflector 13 are both installed in the main body 1 through an adjustable bracket, and the first reflector 12 and the second reflector 13 can adjust the pitch angle, so as to deflect the angle of the laser beam so that it passes through the objective lens module 3 vertically and centered, ensuring minimum distortion.

[0037] The axicon module 2 includes a fixing frame 22, an axicon 23 and a convex lens 24. The fixing frame 22 is fixedly connected to the main body 1. The fixing frame 22 is provided with a first lens barrel 25 and a second lens barrel 26. The first lens barrel 25 is provided with a first fixing member 27, which is connected with the first lens barrel 25 so as to fix the axicon 23 in the first lens barrel 25. The second lens barrel 26 is provided with a second fixing member 28, which is connected with the second lens barrel 26 so as to fix the convex lens 24 in the second lens barrel 26. The phase delay plate 21, the axicon 23, the convex lens 24 and the objective lens module 3 form a Bessel shaping optical path, and the distances between the four optical elements are mutually constrained.

[0038] Specifically, the above-mentioned Bessel shaping converts the energy distribution of the laser from a Gaussian beam into a Bessel distribution. The collimated laser forms an annular laser beam after passing through the axicon 23. The annular laser beam forms an annular collimated beam after passing through the convex lens 24. Then, the annular collimated beam is focused by the objective lens module 3 to form an energy distribution with longer and more uniform ends on the focusing plane. The energy distribution is elliptical, which can be beneficial to the formation of cracks in cutting applications. Of course, the phase delay plate 21 can be removed in hole making applications.

[0039] Specifically, the incident laser entering the main body 1 is a collimated femtosecond pulse laser beam with a wavelength of 100-1200nm, a pulse width of 100fs-20ps (adjustable), a power of 1-100W, and a spot size of 0.1-20mm. The axicon 23 cooperates with a focusing lens with a focal length of 100-200, the Bessel ring diameter is 0.1-20mm, the objective lens module 3 uses a 10-50x objective lens, the convex lens 24 uses a plano-convex lens with a focal length of 50-500mm, the spacing between the axicon 23 and the convex lens 24 is 2-20mm, and the distance between the convex lens 24 and the first reflector 12, the distance between the first reflector 12 and the second reflector 13, and the distance between the second reflector 3 and the objective lens module 3, the sum of the three distances is 250-500mm.

[0040] In the case where there is no need to consider subsequent adjustments, the axicon 23 and the convex lens 24 can be fixed in the lens barrel using ultraviolet shadowless adhesive.

[0041] The light source module includes a lamp tube 6, a point light source 61 is provided in the upper port of the lamp tube 6, a light source reflector 62 is provided in the lower port of the lamp tube 6, and the lower end of the lamp tube 6 is connected to the main body 1 so that the light source reflector 62 is paired with the semi-reflective semi-mirror module 11. It can be understood that the point light source 61 can be irradiated on the processing plane through the objective lens module 3, and the surface feature information of the product is imaged by the coaxial camera 4 through reflection. Further, a target tube 63 is provided between the lower end of the lamp tube 6 and the main body 1, and a first lens 64, a target sheet 65 and a second lens 66 are sequentially provided in the target tube 63, and the first lens 64 and the second lens 66 are conjugate lenses. The light beam generated by the point light source 61 is blocked by the opaque mass on the target sheet 65, and is imaged near the processing plane through the objective lens module 3. The coaxial camera 4 calculates the clarity according to the target image at different height positions, and selects the position with the highest contrast as the target imaging position, thereby realizing the laser focus acquisition of the transparent material surface without image features, and realizing automatic focus monitoring and compensation.

[0042] The upper end of the main body 1 is provided with a camera adjustment seat 41, on which the coaxial camera 4 is mounted, and a two-dimensional fine adjustment structure is provided on the camera adjustment seat 41. The coaxial camera 4 can form an image based on the laser energy distribution on the processing plane, and determine the adjustment method based on whether the image is symmetrical.

[0043] The coaxial camera 4 can also monitor the laser energy distribution diagram. By comparing the brightness change and the triggering laser light signal, the laser light output monitoring can be realized to monitor whether there is leakage triggering and energy attenuation. It can be used as a production monitoring means and as a basis for analyzing abnormalities such as abnormal cracks and blind holes, thereby improving the ability to troubleshoot production problems and saving time for yield increase.

[0044] The above description is only a preferred embodiment of the present invention, so all equivalent changes or modifications made according to the structure, characteristics and principles described in the scope of the patent application of the present invention are included in the scope of the patent application of the present invention.

Claims

1. A processing device based on Bessel optics, comprising a main body (1), characterized in that: The main body (1) is provided with an aperture adjustment module, an axicon module (2), a reflection module and an objective lens module (3); the objective lens module (3) is arranged on the exit port at the lower end of the main body (1); the aperture adjustment module, the axicon module (2), the reflection module and the objective lens module (3) are arranged in sequence along the processing light path; the main body (1) is provided with a coaxial camera (4), a semi-reflective semi-mirror module (11) and a light source module; the coaxial camera (4) is arranged at the upper end of the main body (1) and is arranged in sequence with the semi-reflective semi-mirror module (11) and the objective lens module (3); the light source module is arranged on one side of the main body (1); the light source module is arranged in pair with the semi-reflective semi-mirror module (11).

2. The processing device based on Bessel optics according to claim 1, characterized in that: The aperture adjustment module comprises an incident aperture (5) and an aperture adjustment seat (51); the aperture adjustment seat (51) is fixedly arranged at the incident port at the upper end of the main body (1); the incident aperture (5) is cooperatively connected with the aperture adjustment seat (51); and a two-dimensional fine adjustment structure is provided on the aperture adjustment seat (51).

3. The processing device based on Bessel optics according to claim 2, characterized in that: A cover plate (52) is provided on an opening on one side of the diaphragm adjustment seat (51).

4. The processing device based on Bessel optics according to claim 2, characterized in that: A first aperture (53) and a second aperture (54) are arranged in the main body (1); the incident aperture (5), the first aperture (53), the axicon module (2) and the second aperture (54) are centrally arranged in sequence along a processing optical path.

5. The processing device based on Bessel optics according to claim 4, characterized in that: It also includes a phase delay plate (21), the first aperture (53) is fixedly arranged in the main body (1) via a mounting frame (55), and the phase delay plate (21) can replace the first aperture (53) and is arranged on the mounting frame (55).

6. The processing device based on Bessel optics according to claim 1, characterized in that: The reflection module comprises a first reflection mirror (12) and a second reflection mirror (13); a second diaphragm (54), a first reflection mirror (12), a second reflection mirror (13) and an objective lens module (3) are arranged in sequence along a processing light path; and a third diaphragm (56) is arranged between the first reflection mirror (12) and the second reflection mirror (13).

7. The processing device based on Bessel optics according to claim 1, characterized in that: The axicon module (2) comprises a fixing frame (22), an axicon mirror (23) and a convex lens (24); the fixing frame (22) is fixedly connected to the main body (1); a first lens barrel (25) and a second lens barrel (26) are provided on the fixing frame (22); a first fixing member (27) is provided on the first lens barrel (25); the first fixing member (27) is connected in cooperation with the first lens barrel (25) so as to fix the axicon mirror (23) in the first lens barrel (25); and a second fixing member (28) is provided on the second lens barrel (26); the second fixing member (28) is connected in cooperation with the second lens barrel (26) so as to fix the convex lens (24) in the second lens barrel (26).

8. The processing device based on Bessel optics according to claim 1, characterized in that: The light source module comprises a lamp tube (6), a point light source (61) is arranged in the upper end of the lamp tube (6), a light source reflector (62) is arranged in the lower end of the lamp tube (6), and the lower end of the lamp tube (6) is connected to the main body (1) so that the light source reflector (62) is paired with the semi-reflective and semi-mirror module (11).

9. The processing device based on Bessel optics according to claim 8, characterized in that: A target tube (63) is provided between the lower end of the lamp tube (6) and the main body (1), and a first lens (64), a target sheet (65) and a second lens (66) are sequentially provided in the target tube (63), and the first lens (64) and the second lens (66) are conjugate lenses.

10. The processing device based on Bessel optics according to claim 1, characterized in that: A camera adjustment seat (41) is provided at the upper end of the main body (1), the coaxial camera (4) is mounted on the camera adjustment seat (41), and a two-dimensional fine adjustment structure is provided on the camera adjustment seat (41).

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