A method of laser cutting of glass

Abstract

The present invention discloses a glass cutting method, including a laser device having a signal light of a first wavelength and a pump light of a second wavelength. The laser device is characterized in that the energy of the residual pump light is greater than 15% of the total energy of the pump light. A wavelength splitter is used to split the outgoing laser beam into two beams. The separated residual pump light passes through an offset optical path to form a parallel beam with the outgoing signal beam. The outgoing signal beam and the residual pump light are respectively focused on the glass to be processed. The focused laser spot scans the glass to be processed along a cutting path, with the focused spot of the residual pump light located behind the focused spot of the outgoing signal light in the scanning direction. Microcracks are formed in the glass by the outgoing signal light, and then the residual pump light causes the microcracks in the glass to expand in a controlled manner, thereby achieving glass cutting. The present invention only requires a single laser light source to complete glass cutting in a single process.

Description

TECHNICAL FIELD

[0001] The present application relates to a laser processing method, in particular to a method for processing glass by using laser. BACKGROUND

[0002] In the fields of consumer electronics, semiconductors, new energy, precision optics, aerospace, etc., glass materials are widely used due to their high light transmittance, good strength, wear resistance and special photoelectric functional characteristics. With higher requirements for the efficiency, precision and yield of glass processing in high-end applications, laser processing gradually replaces traditional glass mechanical processing methods.

[0003] As for the laser glass cutting process, the commonly used methods include hidden cutting method, wire cutting method, etc. These methods usually have two process steps, i.e., first forming micro-cracks on the material by using laser (laser cutting step), and then allowing the micro-cracks to expand controllably to separate the glass material to be cut (cracking step). The cracking step can be mechanical cracking, or using another CO2 laser to heat the cracking, etc.

[0004] In this type of processing method, since there are two processing procedures of cutting and cracking, two laser light sources are required, or mechanical cracking or thermal cracking method is used for the cracking procedure, which has more process steps, relatively complex equipment structure, reduces the automation degree of the system, and the process flow is also longer.

[0005] Chinese utility model patent CN218058824U discloses a gantry type double-platform glass cutting and cracking integrated equipment, which comprises a rack assembly, Y-axis linear modules are arranged at both ends of the top of the rack assembly, a gantry assembly is fixed to the top of the rack assembly and located outside the Y-axis linear modules, a picosecond cutting light path and a cracking light path are installed on the top of the gantry assembly, the picosecond cutting light path is located at one end of the cracking light path, X-axis linear modules are arranged on both sides of the gantry assembly, a Z-axis cutting assembly is assembled on one side of one of the X-axis linear modules away from the gantry assembly, and a Z-axis cracking assembly is assembled on one side of the other X-axis linear module away from the gantry assembly. This technical solution arranges the cutting assembly and the cracking assembly on two platforms respectively, one platform can perform cracking while the other platform performs cutting, thereby combining the process flow, shortening the glass conveying time, and accelerating the processing speed by time multiplexing. However, this solution still needs to set two laser light sources, and for each glass, two processes of cutting and cracking are still required. SUMMARY

[0006] The object of the present invention is to provide a glass cutting method which uses a laser light source to complete laser cutting and splitting operations in one process, so as to reduce system complexity and improve laser cutting efficiency.

[0007] To achieve the above-mentioned purpose of the invention, the technical solution adopted by the present invention is: a glass cutting method, providing a laser device, the laser device having a signal light of a first wavelength and a pump light of a second wavelength, the pump light is absorbed in an amplifier and converted into signal light, the outgoing laser beam is composed of the signal light and the unabsorbed residual pump light, the energy of the residual pump light is greater than 15% of the total energy of the pump light, a wavelength splitter is used to split the outgoing laser beam into two beams, namely the outgoing signal beam and the residual pump beam, the separated residual pump light forms a parallel beam with the outgoing signal beam after passing through an offset optical path, the outgoing signal beam and the residual pump beam are respectively focused on the glass to be processed, the focused laser spot scans the glass to be processed along the cutting path, the focused spot of the residual pump beam is located behind the focused spot of the outgoing signal beam in the scanning direction, microcracks are formed in the glass by the outgoing signal beam, and then the residual pump beam causes the microcracks in the glass to expand in a controlled manner to achieve cutting of the glass.

[0008] In the above technical solution, the offset optical path can be achieved by providing an optical glass sheet of a certain thickness, which can be coated on both sides with an anti-reflection coating. For example, the thickness of the optical glass sheet can be 5mm and can be rotated within a range of 0 to 10 degrees to adjust the focus position of the light spot.

[0009] According to a preferred technical solution, during the scanning cutting path, the focus spot of the residual pump beam lags behind the focus spot of the outgoing signal beam by 20 ms and is irradiated on the same position of the glass to be processed.

[0010] In the above technical solution, the first wavelength is 1020nm~1080nm, and the second wavelength is 910nm~980nm.

[0011] In the above technical solution, the initial signal light is provided by a seed laser source, which is a nanosecond or picosecond pulse laser generator.

[0012] In a preferred technical solution, the seed laser source is a pulse directly generated by an electrically modulated semiconductor laser, or a femtosecond mode-locked laser pulse with a wide spectrum that is broadened to a pulse width of hundreds of picoseconds via a dispersion element.

[0013] In the above technical solution, the average output power of the seed laser source is less than 2 watts.

[0014] The application can use a semiconductor laser with a wavelength of 910nm-980nm as a pump source, pump a fiber doped with rare earth ytterbium ions, and form an amplifier to amplify the power of a seed laser source.

[0015] The amplifier can be a single-stage amplifier or a multi-stage amplifier formed by cascading multiple amplifiers. In these amplifiers, the pump laser with a wavelength of 910nm-980nm cannot be completely absorbed and converted into signal light with a wavelength of 1020nm-1080nm. According to the design of the last-stage amplifier, more than 15% of the energy cannot be absorbed and will continue to transmit in the output fiber together with the signal light.

[0016] In the above technical solution, the glass to be processed can be placed on a carrier platform, and the carrier platform is controlled to move in the plane to realize the movement of the focused light spot along the scanning path.

[0017] Alternatively, the movement of the focused light spot along the scanning path can be realized by controlling the laser focusing light path, for example, by a galvanometer or by the mechanical movement of an optical head.

[0018] Thanks to the above technical solution, the application has the following advantages compared with the prior art:

[0019] 1. Due to the pump absorption efficiency, the short-wavelength pump light in the fiber laser cannot be completely absorbed, and this energy becomes waste heat in the prior art and is taken away by the cooling system. The application creatively utilizes the residual pump light to form micro-cracks in the glass by the main output laser, and uses the residual pump light to control the expansion of the micro-cracks in the glass, so that only one laser source is needed to complete the cutting of the glass in one process.

[0020] 2. The application divides the outgoing laser beam into beams with different wavelengths, so that the position of the focused spot of the residual pump light can be adjusted by a deflection light path without affecting the signal light and without being restricted by the pump power of the laser amplifier. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic diagram of a cutting device of an embodiment of the application;

[0022] Figure 2 is a schematic diagram of a light splitting and deflection part in the embodiment. EMBODIMENT

[0023] The application will be further described below in combination with the drawings and embodiments:

[0024] Embodiment one: a laser cutting method of glass, which is realized by using the device shown in Figure 1 The device is shown in Figure 1 and Figure 2As shown, including by laser seed source 1, laser pre-amplifier 3, laser main amplifier 5, pump semiconductor laser 2, 4, laser device, beam splitter and combiner device composed of dichroic mirror 6, 9, 45 degree mirror 7, 8, 45 degree mirror 10 for changing the laser emission direction, galvanometer 11, field lens 12 control laser focus position, the glass to be cut 13 placed on the object platform 14.

[0025] In this embodiment, the laser seed source 1 outputs 1030nm wavelength infrared laser, its repetition frequency is 1MHz, pulse width is 10ps, and power is 50mW. Semiconductor laser 2 outputs 976nm laser, and the laser output by seed source 1 is amplified to 500mW in laser pre-amplifier 3 (fiber amplifier). Semiconductor laser 4 outputs 150W of 976nm laser, and the 1030nm picosecond laser is amplified to 60W in laser main amplifier 5. The signal light transmits through dichroic mirror 6 and continues to transmit in the optical path. Laser main amplifier 5 does not completely absorb all the laser output by semiconductor laser 4, and the residual 50W of 976nm laser is reflected by the dichroic mirror into mirror 7 and continues to transmit in the optical path. The offset optical path is arranged between mirrors 7 and 8, and the direction of the residual 50W power 976nm laser is translated. For example, the offset optical path can adopt an optical glass sheet 16 with a thickness of 5mm and an antireflection film on both sides, which is rotated at an angle in the range of 0-10 degrees, so that the signal light and the pump light are focused on different positions on the sample. The 50W of 976nm residual pump laser and the 60W of 1030nm picosecond laser output by the laser are reflected and transmitted through dichroic mirror 9 respectively to form parallel light beams, and enter galvanometer 11 and field lens 12 through mirror 10, and finally enter the surface of the glass to be cut. As shown in FIG. 15, it is the movement direction of the cutting beam, and the laser spot of the residual pump light is located on the left side of the laser spot of the signal light. Since the beam moves from left to right, the focused spot of the 1030nm signal light first acts to form microcracks, and then the laser spot of the residual pump light acts on the microcracks 20ms later. Under the action of the thermal effect of the 976nm continuous laser, the microcracks grow controllably, and the glass is cut. Figure 2

[0026] The embodiment can reduce the glass cutting process. The system has low complexity, high cutting efficiency, can effectively reduce the equipment and personnel cost of the glass cutting process, and can maintain good laser cutting effect of the glass.​

Claims

1. A glass cutting method, comprising: providing a laser device having a signal light of a first wavelength and a pump light of a second wavelength, wherein the pump light is absorbed and converted into the signal light in an amplifier, wherein: The outgoing laser beam consists of signal light and unabsorbed residual pump light. The energy of the residual pump light is greater than 15% of the total energy of the pump light. A wavelength splitter is used to split the outgoing laser beam into two beams, namely the outgoing signal beam and the residual pump beam. The wavelength splitter is a dichroic mirror. The separated residual pump light forms a parallel beam with the outgoing signal beam after passing through an offset optical path. The offset optical path is an optical glass sheet with adjustable angle arranged in the optical path. The outgoing signal beam and the residual pump beam are respectively focused on the glass to be processed. The focused laser spot scans the glass to be processed along the cutting path. The focused spot of the residual pump beam is located behind the focused spot of the outgoing signal beam in the scanning direction. Microcracks are formed in the glass by the outgoing signal beam. Subsequently, the residual pump beam causes the microcracks in the glass to expand in a controlled manner, thereby achieving glass cutting.

2. The glass cutting method according to claim 1, wherein: During the scanning cutting path, the focus spot of the residual pump beam lags behind the focus spot of the outgoing signal beam by 20ms and irradiates the same position of the glass to be processed.

3. The glass cutting method according to claim 1, wherein: The first wavelength is 1020 nm to 1080 nm, and the second wavelength is 910 nm to 980 nm.

4. The glass cutting method according to claim 1, wherein: The initial signal light is provided by a seed laser source, which is a nanosecond or picosecond pulse laser generator.

5. The glass cutting method according to claim 4, wherein: The seed laser source is a pulse directly generated by an electrically modulated semiconductor laser, or a femtosecond mode-locked laser pulse with a wide spectrum broadened to a pulse width of hundreds of picoseconds via a dispersion element.

6. The glass cutting method according to claim 4, wherein: The average output power of the seed laser source is less than 2 watts.

7. The glass cutting method according to claim 1, wherein: The glass to be processed is placed on a loading platform, and the loading platform is controlled to move within a plane to realize the movement of the focused light spot along the scanning path.

8. The glass cutting method according to claim 1, wherein: By controlling the laser focusing light path, the movement of the focused light spot along the scanning path is achieved.

Images