Device and method for achieving three-dimensional isotropic machining through rotating slits

Abstract

The invention relates to the technical field of laser processing devices, in particular to a device and method for achieving three-dimensional isotropic processing through a rotating slit. The three-dimensional motion platform is used for placing and driving a transparent material to be processed; the slit is provided with a driver to enable the slit to rotate, laser beams emitted by the laser emitting device are subjected to light path adjustment and then pass through the center of the slit to form elliptical light beams, and the elliptical light beams are focused by an objective lens and then are transmitted to the laser receiving device. The three-dimensional isotropic processing of the transparent material is realized by adjusting the rotating speed of the slit and the direct writing speed of the three-dimensional motion platform; according to the invention, the rotatable slit is arranged, a circular Gaussian beam emitted by the laser emitting device passes through the slit to form an elliptical beam, the elliptical beam is rapidly rotated by rapidly rotating the slit, and after the elliptical beam is focused by the objective lens, spatial three-dimensional spherical symmetrical focal field distribution can be obtained in the transparent material, so that three-dimensional isotropic processing is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of laser processing devices, and in particular to a device and method for realizing three-dimensional isotropic processing through a rotating slit. Background Art

[0002] At present, three-dimensional micromachining based on femtosecond laser direct writing (FLDW) has developed into one of the most effective technologies for three-dimensional micromachining of transparent optical materials, and has been widely used in many research fields such as microfluidics, microoptics, microelectronics, photonics, and optofluidics.

[0003] However, the lateral and axial resolutions of the focal spot produced by directly focusing a femtosecond laser are naturally unbalanced, and the axial resolution is significantly elongated, which limits the three-dimensional isotropic manufacturing capability. In order to balance the lateral resolution and axial resolution, some beam shaping technologies have been proposed. Among them, slit shaping technology, as a beam shaping technology, can achieve a one-dimensional circular cross-section parallel to the slit direction. Since the direction of the slit in the existing slit shaping technology is usually fixed, such as the Chinese invention patent with announcement number CN106312303A discloses a device and method for reducing the diameter of the emission mode field of a light waveguide based on femtosecond laser direct writing of transparent materials, it is impossible to achieve three-dimensional isotropic processing inside the glass material using slit shaping technology. Summary of the invention

[0004] The purpose of the present invention is to provide a device and method for realizing three-dimensional isotropic processing by rotating a slit. By setting a rotatable slit, a circular Gaussian beam emitted by a laser emitting device forms an elliptical beam after passing through the slit. The elliptical beam is rotated rapidly by rapidly rotating the slit, and then after being focused by an objective lens, a three-dimensional spherically symmetrical focal field distribution can be obtained inside a transparent material, thereby realizing three-dimensional isotropic processing. In order to achieve the above purpose, the present invention solves the problem through the following technical solutions:

[0005] In a first aspect, the present invention provides a device for realizing three-dimensional isotropic processing by rotating a slit, comprising:

[0006] Laser emitting device;

[0007] A three-dimensional motion platform for placing and driving the transparent material to be processed;

[0008] The slit is equipped with a drive to enable it to rotate. The laser beam emitted by the laser emitting device forms an elliptical beam through the center of the slit after the optical path is adjusted. The elliptical beam is focused by the objective lens, and the three-dimensional isotropic processing of the transparent material is achieved by adjusting the slit rotation speed and the direct writing speed of the three-dimensional motion platform.

[0009] As a further technical solution, it also includes an energy control system, a quarter wave plate, a beam expander and a dichroic mirror. The laser beam emitted by the laser emitting device passes through the energy control system, the quarter wave plate, the beam expander and the dichroic mirror in sequence for optical path processing.

[0010] As a further technical solution, the energy control system consists of a half wave plate and a Glan prism.

[0011] As a further technical solution, the drive is a motor, and the slit is fixed on the rotating shaft of the motor.

[0012] As a further technical solution, the motor is a hollow brushless DC motor.

[0013] As a further technical solution, the processing path of the three-dimensional motion platform is designed by a computer and implemented by computer drive.

[0014] As a further technical solution, the laser emitting device is a femtosecond laser.

[0015] As a further technical solution, an imaging system for real-time observation of the machining process is also included.

[0016] As a further technical solution, the imaging system includes a CCD camera, a convex lens and the objective lens.

[0017] In a second aspect, the present invention provides a processing method for the device for realizing three-dimensional isotropic processing by rotating the slit according to the first aspect, comprising the following steps:

[0018] Placing the transparent material on a three-dimensional motion platform;

[0019] After the femtosecond laser pulse emitted by the femtosecond laser passes through the energy control system, the linear polarized light is converted into circular polarized light by the quarter-wave plate, and then the laser beam size is expanded to the objective lens entrance pupil size by the beam expander, and then irradiated to the center of the slit through the dichroic mirror. At this time, the light beam passing through the slit becomes elliptical, and then focused into the transparent material through the objective lens;

[0020] After the optical path is adjusted, the slit rotation speed is adjusted, and the three-dimensional processing path is designed by the computer to achieve three-dimensional isotropic processing inside the transparent material.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. The slit provided in the present invention is rotatable, and the circular Gaussian light beam emitted by the laser emitting device forms an elliptical light beam after passing through the slit. The elliptical light beam is rapidly rotated by rapidly rotating the slit, and then focused by the objective lens, a three-dimensional spherically symmetrical focal field distribution can be obtained inside the transparent material, thereby realizing three-dimensional isotropic processing.

[0023] 2. Compared with the traditional femtosecond laser direct writing and fixed slit shaping technology, the present invention realizes the rapid change of the slit direction by quickly rotating the slit, and quickly forms a three-dimensional symmetrical spherical processing area near the focus in a short time, which can effectively improve the longitudinal resolution of femtosecond laser processing and solve the problem of asymmetric horizontal and vertical resolution in the traditional femtosecond laser direct writing and fixed slit shaping technology.

[0024] 3. The present invention is provided with an imaging system consisting of an objective lens, a convex lens and a CCD camera, which can observe the entire processing process in real time, can promptly feedback problems arising in the processing process, and provide reference for subsequent processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their description are used to explain the present invention and do not constitute a limitation of the present invention. It should also be understood that these drawings are shown for simplicity and clarity and are not necessarily drawn to scale. The present invention will now be described and explained with additional features and details through the use of the accompanying drawings, in which:

[0026] Figure 1 A schematic diagram of a device for achieving three-dimensional isotropic processing by rotating slits in an embodiment of the present invention is shown.

[0027] In the figure: 1. Femtosecond laser; 2. Half wave plate; 3. Glan prism; 4. Quarter wave plate; 5. Beam expander; 6. Dichroic mirror; 7. Slit; 8. Hollow brushless DC motor; 9. Objective lens; 10. Transparent material; 11. Three-dimensional motion platform; 12. Convex lens; 13. CCD camera. DETAILED DESCRIPTION

[0028] The technical solutions in typical embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0029] Embodiment 1

[0030] like Figure 1 As shown, this embodiment provides a device for achieving three-dimensional isotropic processing by rotating a slit, including a laser emitting device, an energy control system, a quarter-wave plate 4, a beam expander 5, a dichroic mirror 6, a slit 7, an objective lens 9, a three-dimensional motion platform 11 and an imaging system.

[0031] In this embodiment, the laser emitting device adopts a femtosecond laser 1. The laser beam emitted by the femtosecond laser 1 is a circular Gaussian beam.

[0032] The three-dimensional motion platform 11 is used to place and drive the transparent material 10 to be processed. The processing path of the three-dimensional motion platform 11 is designed by a computer and driven by a computer.

[0033] The slit 7 is provided with a drive to enable it to rotate. The laser beam emitted by the laser emitting device forms an elliptical beam through the center of the slit 7 after the optical path is adjusted. The elliptical beam is then focused by the objective lens 9. The three-dimensional isotropic processing of the transparent material 10 is achieved by adjusting the rotation speed of the slit 7 and the direct writing speed of the three-dimensional motion platform 11.

[0034] The slit 7 provided in this embodiment is rotatable. The circular Gaussian light beam emitted by the laser emitting device forms an elliptical light beam after passing through the slit 7. The elliptical light beam is rotated rapidly by rapidly rotating the slit 7. After being focused by the objective lens 9, a three-dimensional spherically symmetrical focal field distribution can be obtained inside the transparent material 10, thereby realizing three-dimensional isotropic processing.

[0035] Compared with the conventional femtosecond laser direct writing and fixed slit shaping technologies, this embodiment realizes a rapid change in the slit direction by rapidly rotating the slit 7, thereby forming a three-dimensionally symmetrical spherical processing area near the focus in a short time, which can effectively improve the longitudinal resolution of femtosecond laser processing and solve the problem of asymmetric horizontal and vertical resolutions in the conventional femtosecond laser direct writing and fixed slit shaping technologies.

[0036] It also includes an energy control system, a quarter wave plate 4, a beam expander 5 and a dichroic mirror 6. The laser beam emitted by the laser emitting device passes through the energy control system, the quarter wave plate 4, the beam expander 5 and the dichroic mirror 6 in sequence for optical path processing.

[0037] In this embodiment, the energy control system is composed of a half wave plate 2 and a Glan prism 3 .

[0038] The laser beam emitted by the femtosecond laser 1 is processed in the optical path through the half wave plate 2, the Glan prism 3, the quarter wave plate 4, the beam expander 5 and the dichroic mirror 6 in sequence. Specifically, after the femtosecond laser pulse emitted by the femtosecond laser 1 passes through the energy control system composed of the half wave plate 2 and the Glan prism 3, the linear polarized light is converted into circular polarized light by the quarter wave plate 4, and then the laser beam size is expanded to the objective lens entrance pupil size by the beam expander 5, and then irradiated to the center of the slit 7 through the dichroic mirror 6. At this time, the light beam passing through the slit 7 becomes elliptical, and then is focused into the transparent material 10 through the objective lens 9.

[0039] The driver is a motor, and the slit 7 is fixed on the rotating shaft of the motor. In this embodiment, the motor is a hollow brushless DC motor 8, which drives the slit to rotate rapidly, thereby realizing a rapid change in the direction of the slit and forming a three-dimensional symmetrical spherical focal field near the focus. This embodiment can realize three-dimensional isotropic processing inside transparent materials such as quartz glass, solve the problem of asymmetric processing resolution in traditional femtosecond laser direct writing and fixed slit shaping technology, and will be applied to fields such as femtosecond laser three-dimensional printing.

[0040] In addition, an imaging system for real-time observation of the processing process is also included. In this embodiment, the imaging system includes a CCD camera 13, a convex lens 12 and an objective lens 9, and the entire processing process is observed in real time through the imaging system composed of the objective lens 9, the convex lens 12 and the CCD camera 13.

[0041] Embodiment 2

[0042] This embodiment provides a processing method of the device for realizing three-dimensional isotropic processing by rotating slits according to the first embodiment, comprising the following steps:

[0043] Placing a transparent material 10 on a three-dimensional motion platform 11;

[0044] The femtosecond laser pulse emitted by the femtosecond laser 1 passes through an energy control system composed of a half wave plate 2 and a Glan prism 3, and then the linear polarized light is converted into circular polarized light by a quarter wave plate 4. The laser beam size is then expanded to the objective lens entrance pupil size by a beam expander 5, and then irradiated to the center of a slit 7 fixed on a hollow brushless DC motor 8 through a dichroic mirror 6. At this time, the light beam passing through the slit 7 becomes an ellipse, and then is focused into a transparent material 10 through an objective lens 9.

[0045] After the optical path is adjusted, the rotation speed of the hollow brushless DC motor 8 is adjusted, and the three-dimensional processing path is designed by the computer to achieve three-dimensional isotropic processing inside the transparent material 10. The entire processing process is observed in real time through the imaging system.

[0046] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A device for realizing three-dimensional isotropic processing by rotating a slit, characterized in that: include: Laser emitting device; A three-dimensional motion platform for placing and driving the transparent material to be processed; The slit is equipped with a drive to enable it to rotate. The laser beam emitted by the laser emitting device forms an elliptical beam through the center of the slit after the optical path is adjusted. The elliptical beam is focused by the objective lens, and the three-dimensional isotropic processing of the transparent material is achieved by adjusting the slit rotation speed and the direct writing speed of the three-dimensional motion platform.

2. The device for realizing three-dimensional isotropic processing by rotating slits according to claim 1, characterized in that: It also includes an energy control system, a quarter wave plate, a beam expander and a dichroic mirror. The laser beam emitted by the laser emitting device passes through the energy control system, the quarter wave plate, the beam expander and the dichroic mirror in sequence for optical path processing.

3. The device for realizing three-dimensional isotropic processing by rotating slits as claimed in claim 2, characterized in that: The energy control system consists of a half wave plate and a Glan prism.

4. The device for realizing three-dimensional isotropic processing by rotating slits as claimed in claim 1, characterized in that: The drive is a motor, and the slit is fixed on the rotating shaft of the motor.

5. The device for realizing three-dimensional isotropic processing by rotating slits as claimed in claim 4, characterized in that: The motor is a hollow brushless DC motor.

6. The device for realizing three-dimensional isotropic processing by rotating slits as claimed in claim 1, characterized in that: The processing path of the three-dimensional motion platform is designed by a computer and implemented by computer driving.

7. The device for realizing three-dimensional isotropic processing by rotating slits as claimed in claim 1, characterized in that: The laser emitting device is a femtosecond laser.

8. The device for realizing three-dimensional isotropic processing by rotating slits as claimed in claim 1, characterized in that: Also included is an imaging system for real-time viewing of the machining process.

9. The device for realizing three-dimensional isotropic processing by rotating slits as claimed in claim 8, characterized in that: The imaging system includes a CCD camera, a convex lens and the objective lens.

10. The processing method of the device for realizing three-dimensional isotropic processing by rotating slits according to any one of claims 1 to 9, characterized in that: The following steps are involved: Placing the transparent material on a three-dimensional motion platform; After the femtosecond laser pulse emitted by the femtosecond laser passes through the energy control system, the linear polarized light is converted into circular polarized light by the quarter-wave plate, and then the laser beam size is expanded to the objective lens entrance pupil size by the beam expander, and then irradiated to the center of the slit through the dichroic mirror. At this time, the light beam passing through the slit becomes elliptical, and then focused into the transparent material through the objective lens; After the optical path is adjusted, the slit rotation speed is adjusted, and the three-dimensional processing path is designed by the computer to achieve three-dimensional isotropic processing inside the transparent material.

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