Horizontal focus-adjustable double-lens laser cutting system

Abstract

The invention discloses a horizontal controllable double-lens laser cutting system. The system comprises a laser light source for emitting picosecond laser, a beam expanding lens, a reflecting mirror group, a semi-transparent and semi-reflecting mirror, a Bessel lens, a numerical control guide rail, a numerical control machine tool and a water cooling machine, a light path of a traditional laser cutting system is changed and adjusted into a horizontal controllable double-lens cutting method, laser at a laser light source is amplified through a beam expander, the amplified light beam is split through a semi-transparent and semi-reflecting mirror, about 50% of light beam energy penetrates through the semi-transparent and semi-reflecting mirror to enter a Bessel laser lens on the right side, and the light beam energy is converted into light beam energy; the rest of energy is reflected into the Bessel lens on the left side; the numerical control machine tool is connected with the computer, a clamp is arranged on the machine tool and used for fixing a sample, the computer controls a machining path, the numerical control guide rail is connected with the computer and controls the laser focusing position of the lens, fragile materials with a certain thickness can be machined, and the modified layer area of the section of the machined sample can be adjusted.

Description

Technical Field

[0001] The present invention relates to the field of ultrashort pulse laser processing, and in particular to a horizontal dual-lens laser cutting system and a system structure thereof. Background Art

[0002] Transparent brittle materials such as glass and crystals of various properties have the characteristics of small thermal expansion coefficient, high hardness, good corrosion resistance, high strength and excellent photoelectric properties. They are widely used in aerospace, national defense and optoelectronics. With the rapid development of the information industry, glass-based liquid crystal displays (LCD), plasma displays (PDP), light-emitting diode displays (LED) and organic light-emitting diode displays (OLED) are widely used in electronic devices such as televisions, computers and mobile phones. In order to further improve the product quality and impact resistance of electronic semiconductors, in recent years, chemically strengthened glass with higher strength has appeared to prevent scratches and impact breakage on the screen, which is used for the cover of electronic products, and sapphire, which is second only to diamond in hardness, is used for the display screen and camera of electronic products. Obviously, these brittle transmission materials must go through the cutting and drilling process to form the required shaped products. With the improvement of the quality standards of electronic products, the reduction of structural dimensions and the increase of functional requirements, the requirements for the precision, quality and efficiency of the cutting and processing of brittle transmission materials are also getting higher and higher. Therefore, while improving the cutting efficiency of brittle transmission materials, obtaining higher cutting precision and quality is the current goal of the cutting and processing of brittle transmission materials.

[0003] Ultrashort pulse lasers have the characteristics of short pulse width, high peak intensity, and high repetition frequency. Compared with traditional long pulse width lasers, the duration of ultrashort pulse laser pulses is less than the time it takes for heat to be transferred to the lattice. When using ultrashort pulse laser processing, the laser action area reaches an extremely high temperature in a very short time, causing the material in the action area to instantly change from solid to gas or plasma state and separate, which can effectively overcome the thermal effects of materials outside the thermal shadow of long pulse laser processing. It has significant advantages in the processing of materials with high melting points and high hardness, and can achieve high-quality processing of brittle materials.

[0004] The main lobe diameter of the Bessel beam is small, the propagation distance is long, and it has self-repairing properties, that is, after the beam is blocked by an obstacle, it can restore its original characteristics after a certain transmission distance. Therefore, Bessel beams are widely used in many fields such as optical collimation and measurement, biological imaging, ion micromanipulation, and laser micromachining. In recent years, pulsed lasers based on Bessel beams have been widely used in micro-nano processing of hard and brittle materials, such as surface microstructures, drilling, and microchannel manufacturing.

[0005] However, when the processing thickness of ultrashort pulse laser exceeds the focusing depth of the lens, the speed and quality of laser cutting materials will decrease, and it may even be impossible to achieve the splitting operation of the processed material, which greatly limits the application scope of ultrashort pulse laser processing of brittle materials.

[0006] Therefore, a horizontal dual-lens laser cutting system was developed, which irradiates the sample from both the positive and negative directions, increases the modified layer interval, reduces the difficulty of laser cutting materials with a certain thickness, and at the same time, the position of the modified layer is controllable, which greatly improves the processing quality and has practical application value. Summary of the invention

[0007] The purpose of the present invention is to design a horizontal adjustable focus dual-lens laser cutting system in order to solve the above problems.

[0008] The present invention achieves the above-mentioned purpose through the following technical solutions: The horizontal focusable dual-lens laser cutting system has an overall structure including a laser light source for emitting picosecond laser, a beam expander, a reflector group, a semi-transparent and semi-reflective mirror, a Bessel lens, a CNC machine tool, a CNC guide rail, a computer and a water cooler.

[0009] Preferably, the laser seed source frequency is 30 MHz, the laser wavelength is 1064 nm, the laser pulse width is 15 ps, and the laser operating frequency is 50-3000 kHz.

[0010] Preferably, the beam expander is a Galilean beam expander system suitable for 1064 nm wavelength and with optional 2X-10X magnification.

[0011] Preferably, the reflector has a high reflectivity of 99.5% and is fixed on the optical rail for adjusting the optical path.

[0012] Preferably, the semi-transparent and semi-reflective mirror is a lens with a transmittance of 50% for a light beam with a wavelength of 1064 nm.

[0013] Preferably, the semi-transparent and semi-reflective mirror transmits the light into the right Bessel lens, and the reflected light beam passes through the reflector and enters the left Bessel lens to generate a Bessel beam for cutting.

[0014] Preferably, the internal cone bottom angle of the Bessel lens is 5°, the refractive index is 1.51, the 4F system demagnification factor is 8, and the focal depth of the lens in air is 2 mm.

[0015] Preferably, the CNC guide rail is fixed on a movable Z-axis of a CNC machine tool, the guide rail has a fixture for fixing the dual lenses, and the positioning accuracy of the guide rail is ±5 μm.

[0016] Preferably, the motor of the CNC machine tool can move in the X direction and the Y direction, with a repeatability accuracy of ±2 μm and a positioning accuracy of ±5 μm.

[0017] Preferably, the frequency detection component receives the reflected light beam from the semi-transparent and semi-reflective mirror for detection, and inputs the detection signal into the computer.

[0018] Preferably, the computer is connected to and controls the laser output and the movement of the CNC machine tool, and the computer receives and feeds back the frequency detection component information in real time.

[0019] Preferably, the cooling device is a water cooler to control the laser temperature to be maintained at about 25°C.

[0020] Horizontal adjustable focus dual-lens laser cutting system, the system structure is assembled according to the following steps: S1. The laser is connected to a computer, and the output beam quality is controlled by the computer; S2. The laser is connected to a water cooler and placed above the water cooler. The water cooler controls the laser temperature to be maintained at about 25°C. S3, the beam expander is located at the laser outlet, and the laser output beam enters the beam expander to achieve beam expansion; S4, reflectors 1, 2, 3, 4 and the semi-transparent and semi-reflective mirror are fixed on the guide rail, and the beam after beam expansion passes through reflector 2 and enters the semi-transparent and semi-reflective mirror; S5, the light beam reflected by the semi-transparent and semi-reflective mirror passes through the reflectors 2 and 3 and enters the Bessel lens 1; S6, the half-transparent and half-reflective mirror projected light beam passes through the reflector 4 and enters the Bessel lens 2; S7, Bessel lenses 1 and 2 are fixed on the CNC guide rail; S8, the CNC guide rail is fixed on the movable Z axis of the machine tool; S9, CNC machine tools, and CNC guide rails are connected to a computer, and the computer controls the output quality of the laser, the focusing position of the dual lenses, and the CNC machine tools in real time.

[0021] Preferably, in step S5, the focal lengths of the two lenses in the Bessel lenses 1 and 2 are 120 mm and 15 mm respectively, and the demagnification factor of the constructed 4F system is 8.

[0022] The beneficial effects of the present invention are: 1. By using picosecond ultrashort pulse lasers, cold processing of transparent hard and brittle materials can be achieved with micron-level processing accuracy, which can effectively reduce the edge collapse of brittle materials and improve processing quality.

[0023] 2. By using Bessel lens, the traditional Gaussian beam is transformed into a Bessel beam, and the beam energy is redistributed, so that the processing focus has a long focal depth, invisible cutting with internal modification can be achieved, and the processing quality of transparent brittle materials can be effectively improved.

[0024] 3. By adding a semi-transparent and semi-reflective mirror to split the light beam, two Bessel lenses are used to inject from the left and right sides of the processing material respectively. The laser focus can be controlled by computer-controlled CNC guide rails, which greatly improves the processing quality of transparent hard and brittle materials with a certain thickness. At the same time, the position of the modified layer of the processing section can be controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the Bessel beam cutting system with frequency detection in the present invention; Figure 2 Schematic diagram of the structure of Bessel lens; In the figure: 1 - picosecond laser, 2 - beam expander, 3 - reflector 1, 4 - semi-transparent and semi-reflective mirror, 5 - reflector 2, 6 - reflector 3, 7 - Bessel lens 1, 8 - reflector 4, 9 - Bessel lens 2, 10 - CNC guide rail, 11 - CNC machine tool, 12 - computer, 13 - water cooler. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0028] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0029] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use, or are directions or positional relationships commonly understood by those skilled in the art. These directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0030] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0031] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms such as "setting" and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings.

[0033] 1. If Figure 1 As shown, the Bessel beam cutting system with frequency detection has an overall structure including a laser light source (1) for emitting picosecond laser, a beam expander (2), a reflector 1 (3), a semi-transparent and semi-reflective mirror (4), a reflector 2 (5), a reflector 3 (6), a Bessel lens 1 (7), a reflector 4 (8), a Bessel lens 2 (9), a CNC guide rail (10), a CNC machine tool (11), a computer (12) and a water cooler (13). The seed source frequency of the picosecond laser 1 is 30 MHz, the laser wavelength is 1064 nm, the laser pulse width is 15 ps, and the laser operating frequency is 50-3000 kHz. The beam expander 2 is a Galilean beam expander system suitable for a 1064 nm wavelength and with an optional magnification of 2X-10X. The reflector groups 3, 5, 6, and 8 have a high reflectivity of 99.5% and are fixed on the optical guide rail for adjusting the optical path. The semi-transparent and semi-reflective mirror 4 is a lens with a transmittance of 50% for a 1064 nm wavelength beam. The bottom angle of the cone inside the Bessel lens 7, 9 is 5°, the refractive index is 1.51, the demagnification coefficient of the 4F system is 8, and the focal depth of the lens in the air is 2 mm. The CNC guide rail 10 is used to fix the Bessel lens, and the guide rail positioning accuracy is ±5 μm. The motor of the CNC machine tool 11 can move along the X direction and the Y direction, with a repeatability accuracy of ±2 μm and a positioning accuracy of ±5 μm. The computer 12 connects and controls the laser, the CNC guide rail and the CNC machine tool. The water cooler 13 controls the laser temperature to maintain at about 25 ℃.

[0034] Horizontal adjustable focus dual-lens laser cutting system, the system structure is assembled according to the following steps: S1. The laser is connected to a computer, and the output beam quality is controlled by the computer; S2. The laser is connected to a water cooler and placed above the water cooler. The water cooler controls the laser temperature to be maintained at about 25°C. S3, the beam expander is located at the laser outlet, and the laser output beam enters the beam expander to achieve beam expansion; S4, reflectors 1, 2, 3, 4 and the semi-transparent and semi-reflective mirror are fixed on the guide rail, and the beam after beam expansion passes through reflector 2 and enters the semi-transparent and semi-reflective mirror; S5, the light beam reflected by the semi-transparent and semi-reflective mirror passes through the reflectors 2 and 3 and enters the Bessel lens 1; S6, the half-transparent and half-reflective mirror projected light beam passes through the reflector 4 and enters the Bessel lens 2; S7, Bessel lenses 1 and 2 are fixed on the CNC guide rail; S8, the CNC guide rail is fixed on the movable Z axis of the machine tool; S9, CNC machine tools, and CNC guide rails are connected to a computer, and the computer controls the output quality of the laser, the focusing position of the dual lenses, and the CNC machine tools in real time.

[0035] It can be seen that the above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several optical path improvements and beam shaping can be made without departing from the technical principles of the present invention. These improvements and shaping should also be regarded as the scope of protection of the present invention.

Claims

1. Horizontal adjustable focus dual-lens laser cutting system, characterized by: The overall structure includes a laser light source (1) for emitting picosecond laser, a beam expander (2), a reflector 1 (3), a semi-transparent and semi-reflective mirror (4), a reflector 2 (5), a reflector 3 (6), a Bessel lens 1 (7), a reflector 4 (8), a Bessel lens 2 (9), a CNC guide rail (10), a CNC machine tool (11), a computer (12), and a water cooler (13).

2. The horizontal adjustable focus dual-lens laser cutting system according to claim 1, characterized in that: The laser seed source frequency is 30 MHz, the laser wavelength is 1064 nm, the laser pulse width is 15 ps, and the laser operating frequency is 50-3000 kHz.

3. The horizontal adjustable focus dual-lens laser cutting system according to claim 1, characterized in that: The beam expander is a Galilean beam expander system suitable for 1064 nm wavelength and with optional 2X-10X magnification.

4. The horizontal focus-adjustable dual-lens laser cutting system according to claim 1, characterized in that: The reflector 1 has a high reflectivity of 99.5% and is fixed on the optical rail to adjust the optical path and reflect the light beam expanded by the beam expander into the semi-transparent and semi-reflective mirror.

5. The horizontal focus-adjustable dual-lens laser cutting system according to claim 1, characterized in that: The semi-transparent and semi-reflective mirror is a lens with a transmittance of 50% for a beam of 1064 nm wavelength.

6. The horizontal focus-adjustable dual-lens laser cutting system according to claim 1, characterized in that: The reflector 2 and the reflector 3 have a high reflectivity of 99.5% and are fixed on the optical rail to adjust the optical path and inject the light beam reflected by the semi-transparent and semi-reflective mirrors into the Bessel lens 1.

7. The horizontal focus-adjustable dual-lens laser cutting system according to claim 1, characterized in that: The base angle of the axon inside Bessel lens 1 and Bessel lens 2 is 5°, the refractive index is 1.51, the demagnification factor of the 4F system is 8, and the focal depth of the lens in air is 2 mm.

8. The horizontal focus-adjustable dual-lens laser cutting system according to claim 1, characterized in that: The reflector 4 has a high reflectivity of 99.5% and is fixed on the optical rail to adjust the optical path and inject the light beam reflected by the semi-transparent and semi-reflective mirror into the Bessel lens 2.

9. The horizontal focus-adjustable dual-lens laser cutting system according to claim 1, characterized in that: The CNC guide rail is fixed on the movable Z-axis of the CNC machine tool. The guide rail has a fixture for fixing the dual lenses, and the positioning accuracy of the guide rail is ±5 μm.

10. The horizontal focus-adjustable dual-lens laser cutting system according to claim 1, characterized in that: The CNC machine tool motor can move in the X and Y directions with a repeatability of ±2 μm and a positioning accuracy of ±5 μm, and has a fixture that can be used to fix the sample.

11. The horizontal focus-adjustable dual-lens laser cutting system according to claim 1, characterized in that: The computer connects and controls the laser output, CNC guide rail movement and CNC machine tool movement.

12. The horizontal focus-adjustable dual-lens laser cutting system according to claim 1, characterized in that: The cooling device selects a water cooler to control the laser temperature to maintain around 25 ℃.

13. The horizontal focus-adjustable dual-lens laser cutting system according to claim 1, characterized in that: The system structure is assembled in the following steps: S1. The laser is connected to a computer, and the output beam quality is controlled by the computer; S2. The laser is connected to a water cooler and placed above the water cooler. The water cooler controls the laser temperature to be maintained at about 25°C. S3, the beam expander is located at the laser outlet, and the laser output beam enters the beam expander to achieve beam expansion; S4, reflectors 1, 2, 3, 4 and the semi-transparent and semi-reflective mirror are fixed on the guide rail, and the beam after beam expansion passes through reflector 2 and enters the semi-transparent and semi-reflective mirror; S5, the light beam reflected by the semi-transparent and semi-reflective mirror passes through the reflectors 2 and 3 and enters the Bessel lens 1; S6, the half-transparent and half-reflective mirror projected light beam passes through the reflector 4 and enters the Bessel lens 2; S7, Bessel lenses 1 and 2 are fixed on the CNC guide rail; S8, the CNC guide rail is fixed on the movable Z axis of the machine tool; S9, CNC machine tools, and CNC guide rails are connected to a computer, and the computer controls the output quality of the laser, the focusing position of the dual lenses, and the CNC machine tools in real time.

14. The horizontal dual-lens laser cutting system according to claim 1, characterized in that: In step S6, the focal lengths of the two lenses in the Bessel lenses 1 and 2 are 120 mm and 15 mm respectively, and the demagnification factor of the constructed 4F system is 8.

Images