TW201722605A - Laser cutting method of brittle material, and laser cutter to reduce the temperature difference between the focused point and the surroundings of the processed material resulted from the over-concentrated distribution of laser beam energy - Google Patents

Abstract

The present invention is a laser cutting method of brittle material, especially a laser cutting method to reduce the occurrences of edge collapse phenomenon of brittle material, which is mainly to use a polarized optical element in the optical system of laser cutter to proceed with beam shaping modification to the laser light source. By the beam shaping modification method, the laser beam with Gaussian distribution is reshaped into a laser beam with Bessel distribution. Its effect is to reduce the temperature difference between the focused point and the surroundings of the processed material resulted from the over-concentrated distribution of laser beam energy, so as to reduce the edge collapse phenomenon due to thermal stress.

Description

Laser cutting method for hard and brittle materials and laser cutting machine

The invention relates to a laser cutting method for hard and brittle materials, in particular to a laser cutting method for reducing the phenomenon of chipping of hard and brittle materials.

In recent years, laser cutting technology has been commonly used to cut hard transparent materials such as light-emitting diode substrates, sapphire substrates or reinforced glass.

The laser cutting technology focuses on the material to be processed by laser light to produce local hot melt damage. The processed material undergoes a linear scan of the laser light to produce continuous damage marks, and then the material to be processed is cut by mechanical splitting. Separation.

The laser cutting machine mainly comprises a laser light source, a laser optical system and a linear scanning motion mechanism.

The laser source mainly provides a high-energy laser beam, and the laser source can be a high-energy laser source device of different wavelengths (for example, picosecond laser, femtosecond laser, etc.), and the laser cutting machine usually needs to use an energy. A controller for regulating the energy of the laser beam.

The laser optical system mainly controls the laser beam into a processable high-energy laser spot, and the laser beam of the laser source is adjusted to be focused by the laser beam control module including a plurality of optical lenses or components. A high-energy laser spot on the surface of the workpiece, wherein the laser beam control module usually includes a beam expander, a mirror group, a curved mirror, and an objective optical element, wherein the beam expander expands the laser beam of the laser source In the larger diameter laser beam, the mirror group is used to change the optical path of the laser beam, and the curved mirror and the objective lens combination adjust the focus of the laser beam and its depth of field.

The linear scanning motion mechanism is mainly a device for linearly operating a high-energy focused laser beam on a surface of a workpiece, and may be a position of an objective lens in a fixed laser optical system, and moving a workpiece on the XY table, or It is the workpiece on the fixed table, and the position of the objective lens in the moving laser system can be achieved by adjusting the position and angle of the mirror group in the laser beam control module.

The light intensity distribution of a general laser light source is a Gaussian distribution, which is characterized in that the light intensity of the laser light center point is much higher than the periphery thereof, and the energy of the laser light source is extremely concentrated in a small range of the center point.

For metal materials with high thermal conductivity and ductility, the laser beam energy of the Gaussian distribution during laser cutting processing concentrates the metal material on the workpiece without excessive temperature difference between the material at the focus point and its surrounding materials. Therefore, the cracking of the processed material does not occur, so that the energy of the laser light source can be increased as much as possible to speed up the processing efficiency of the laser cutting.

For non-metallic materials with low thermal conductivity and hardness such as ceramics, glass or single crystals, the laser light with excessively concentrated energy produces a temperature difference between the focus material and its surrounding materials, thus generating considerable thermal stress, in which thermal stress is further The phenomenon of chipping occurs, and the chipping phenomenon causes the cutting surface to be uneven or the cutting surface to be broken. The uneven or broken cutting surface is the reason why the processing quality is inferior or unstable when the conventional laser cutting technology is applied to the hard and brittle non-metal materials.

For cutting non-metallic materials, some laser cutting methods reduce the laser damage by reducing the energy of the laser source, or avoiding unevenness or cracking of the cutting surface by multiple round-trip processing, although it can reduce the hardness of the processed material. The result of brittle collapse, but this will significantly reduce the efficiency of cutting.

In order to improve the processing quality of the conventional laser cutting non-metallic materials, the invention provides a laser cutting method, in particular, a laser cutting method for reducing the chipping phenomenon of hard and brittle materials, mainly in the laser cutting method. In the optical system of the laser cutting machine, the laser source is modified by beam shaping, and the Gaussian-distributed laser beam is modified into a Bezoic laser beam by the beam shaping modification method, and the effect can reduce the lightning. The excessive concentration of the beam energy causes the temperature difference between the material to be processed and the surrounding material to reduce the chipping caused by thermal stress.

The invention provides a laser cutting machine, comprising a laser light source, a laser beam control module and a linear scanning motion mechanism, wherein a polarized optical component is used in the laser beam control module, and the polarization is transmitted through the polarization The component forms the laser beam into a polarized laser beam, wherein the polarized optical component is selected from a polarization cone mirror, and the Gaussian-distributed laser beam is converted into light intensity through the polarization cone mirror The more uniform polarization Besau beam reduces the excessive concentration of the laser beam energy at the center point, thus causing the problem that the processing material is too different in temperature at the processing interface between the focus point and its periphery, thereby reducing the thermal stress caused by chipping. The obvious advantage is that it does not have to reduce the efficiency of the cutting process and improve the quality of the cutting process.

11‧‧‧Laser light source device

12‧‧‧Energy Controller

13‧‧‧Laser beam

21‧‧‧ Beam expander

211‧‧‧Laser beam

22‧‧‧Polarized cone mirror

221‧‧‧Polarized laser beam

23‧‧‧Mirror group

24‧‧‧ curved mirror

25‧‧‧ Objective lens

251‧‧‧Laser focused beam

3‧‧‧Processed objects

Figure 1 is a schematic illustration of the optical system of the laser cutting machine of the present invention.

In an embodiment of the present invention, the present invention provides a laser cutting method using a laser cutting program comprising: providing a laser light source and an energy controller thereof; and providing a laser optical system including a beam steering module having optical components such as a beam expander, a mirror group, a curved mirror, and an objective lens; and a linear scanning motion mechanism for utilizing a linear scanning motion mechanism in the laser cutting program to generate a focused beam of the optical system The beam is sequentially scanned and focused on the surface of the workpiece; wherein the beam steering module uses at least one deflecting cone mirror, and the Gaussian-distributed laser beam is transformed into a Besso-distributed thunder through the polarizing cone mirror The beam is beamed while the laser beam is polarized.

In an embodiment, the present invention provides an optical system for a laser cutting machine, comprising a laser light source and a laser beam control module; wherein the laser light source comprises a laser light source device, and an energy controller of the laser beam The laser beam control module includes at least: a beam expander mirror for expanding the diameter of the laser beam; and a polarization cone mirror that forms the laser beam by a polarization cone mirror a polarized laser beam; a mirror set including a number of mirrors for regulating the path of the laser beam; a curved mirror for adjusting the focused depth of field of the laser beam; and an objective lens For focusing the laser beam, focusing the laser beam onto the surface of the object being processed.

In an embodiment, the laser cutting process is performed using the following devices: a laser light source, and a laser source suitable for cutting a hard transparent material such as a light emitting diode substrate, a sapphire substrate or a reinforced glass, including a picosecond laser or For femtosecond lasers, conventional laser sources with wavelengths between 266 nm and 2000 nm can be applied to cut a hard transparent non-metallic material. This embodiment uses a femtosecond laser with a wavelength of 1064 nm; a controller for regulating the energy of the laser beam, the energy of the laser beam being determined by the processing conditions of the cutting program; a laser optical system comprising a beam expander, a mirror group, and a polar A beam steering module for an optical component such as a cone mirror, a curved mirror, and an objective lens; wherein the beam expander expands the laser beam of the laser source into a larger diameter mine by using a combination of one or a plurality of lenses in a multiple increase manner The beam of light, the energy of the larger diameter laser beam is more dispersed, can avoid damage to the subsequent beam-regulating optical components; wherein the mirror group is required for the space efficient use of the laser cutting machine Adjusting the path of the laser beam, the laser light beam guided to the objective lens by using a plurality of the output mirror. In addition, the laser beam can be coupled into the fiber and the laser beam can be transmitted by the fiber. Therefore, the mirror group can also be used instead. Fiber optic module.

In the embodiment, a polarization cone mirror is used. In this embodiment, a polarization cone mirror is used, and the purpose is to transform the Gaussian-distributed laser beam into a Besso-derived laser beam through the cone mirror structure of the polarization cone mirror. In order to avoid concentration of energy, the center point is distributed, and the laser beam is polarized by a polarization mirror to form a polarized laser beam to regulate the energy distribution, wherein the energy of the polarized laser beam is adjusted. The high point is sequentially rotated around the optical focus to form an annular distribution, and the effect thereof particularly helps to reduce the difference in energy absorption between the center and the periphery of the optical focus, thereby effectively reducing the thermal stress therebetween; Curved mirrors and objective lenses use a combination of curved mirrors and objective lenses to determine the depth of focus of the laser beam. For different laser cutting operations, different focal depths must be used to adjust the distance between the curved mirror and the objective. To adjust the focused depth of field of the laser beam, the objective lens uses its focusing function to focus the laser beam onto the surface of the object being processed; and a linear scanning motion mechanism, Linear scanning is performed by sequentially changing the X coordinate and the Y coordinate. The laser scanning mechanism uses a linear scanning motion mechanism to sequentially scan the laser beam generated by the optical system on the surface of the workpiece. This embodiment adopts The object to be processed is fixed on the workbench, and only the linear scanning type moving focusing objective lens can adjust the position and angle of the mirror group in the laser beam control module, so that the objective lenses at different positions can be received by the laser. The beam, thus moving the objective lens position in the laser system in sequence, allows the laser beam to be linearly scanned to focus on the surface of the workpiece.

Referring to FIG. 1, the figure is a schematic diagram of an embodiment of an optical system of the laser cutting machine of the present invention.

The optical system of the laser cutting machine of the present invention comprises a laser light source and a laser beam control module, wherein the laser light source comprises a laser light source device 11 and an energy controller 12 thereof, and the laser light source device of the embodiment 11 uses a femtosecond laser having a wavelength of 1064 nm, the laser source of which outputs a laser beam 13 through the energy controller 12.

The laser beam control module is composed of a plurality of optical lenses or optical components, wherein the laser beam control module 2 includes at least: a beam expanding mirror 21 for expanding the diameter of the laser beam 13 and the laser The beam 13 is formed by the beam expander 21 to form a laser beam 211 having a larger beam diameter than the laser beam 13; a deflecting cone 22 that transmits the laser beam 211 through the deflecting cone 22 Forming a polarization laser beam 221; a mirror group 23, which adjusts the path of the laser beam according to the space utilization requirements of the laser cutter, and uses a plurality of mirrors to guide the polarization laser beam 221 to On the objective lens of the output beam, in addition to the spatial design requirements of the laser cutting machine, a mirror group can also be arranged between the beam expander 21 and the deflecting cone 22 23 to change the path of the laser beam; and a curved mirror 24 and an objective lens 25, the combination of which is used to adjust the focal length and focus depth of the laser output beam, wherein the objective lens 25 focuses the polarized laser beam 221 into a laser The light beam 251 is focused and focused on the surface of the object 3 to be processed.

11‧‧‧Laser light source device

12‧‧‧Energy Controller

13‧‧‧Laser beam

21‧‧‧ Beam expander

211‧‧‧Laser beam

22‧‧‧Polarized cone mirror

221‧‧‧Polarized laser beam

23‧‧‧Mirror group

24‧‧‧ curved mirror

25‧‧‧ Objective lens

251‧‧‧Laser focused beam

3‧‧‧Processed objects

Claims (4)

A laser cutting machine includes a laser light source, a laser beam control module and a linear scanning motion mechanism, wherein a polarized optical component is used in the laser beam control module, and the polarized optical component is used The laser beam of the laser source is transformed into a polarized laser beam, thereby reducing the temperature difference of the processing interface caused by the excessive concentration of the laser beam energy, thereby reducing the phenomenon of chipping caused by thermal stress. A laser cutting machine according to claim 1, wherein the polarized optical element is selected from a polarization cone mirror. A laser cutting method for performing a laser cutting program using a device comprising: a laser source, and an energy controller of the beam; and a laser optical system including a beam expander, a mirror group, a beam steering module for an optical component such as a curved mirror and an objective lens; and a linear scanning motion mechanism for scanning a focused laser beam generated by the optical system on the surface of the workpiece by using a linear scanning motion mechanism in a laser cutting program The light beam control module uses at least one polarization cone mirror through which the Gaussian-distributed laser beam is transformed into a Besso-derived laser beam, and the laser beam is polarized simultaneously. . An optical system of a laser cutting machine, comprising a laser light source and a laser beam control module; wherein the laser light source comprises a laser light source device and an energy controller of the laser beam; wherein the laser beam is regulated The module includes at least: a beam expander mirror for expanding a diameter of the laser beam; and a polarization cone mirror that forms a polarized laser beam through the polarization cone mirror a mirror set comprising a number of mirrors for regulating the path of the laser beam; a curved mirror for adjusting the focused depth of field of the laser beam; and an objective lens for focusing the laser The beam focuses the laser beam on the surface of the object being processed.