Hybrid laser welding method and device for transparent brittle materials

Abstract

The invention belongs to the technical field of laser processing, and particularly discloses a hybrid laser welding method and device for transparent brittle materials. The method comprises the following steps: S1, focusing an ultrafast laser beam at a position where two to-be-welded transparent brittle materials are in contact with each other to form a white semi-transparent initial weld joint toimplement preliminary welding; and S2, focusing a continuous laser beam at the position of the white semi-transparent initial weld joint to implement final welding. The device comprises an ultrafastlaser beam generation module and a continuous laser beam generation module, wherein the ultrafast laser beam generation module is used for implementing initial welding; and the continuous laser beam generation module is used for implementing final welding. By the hybrid laser welding method and device for transparent brittle materials, firm welding of the two transparent brittle materials with a large contact gap can be realized. The hybrid laser welding method and device for transparent brittle materials have the advantages of firm and reliable welding, wide application range, simple technological process and the like.

Description

technical field [0001] The invention belongs to the technical field of laser processing, and more specifically relates to a method and device for composite laser welding of transparent and brittle materials. Background technique [0002] Transparent and brittle materials such as glass, silicon, and sapphire play an indispensable role in daily life and scientific research and production because of their stable chemical properties and excellent physical properties including light transmission, insulation, corrosion resistance, and high hardness. role. In many applications, multiple transparent and brittle material parts that are assembled and sealed together are used, such as the assembly of lenses in optics, which require multiple lenses to withstand a specific optical power density passing through the aperture; optoelectronics In the packaging of semiconductor sensors corresponding to specific spectra, an insulating shell that is transparent to the signal light of the corre...

AI Technical Summary

Problems solved by technology

Ultrafast laser utilizes extremely high peak power density and ultrashort laser pulses to generate nonlinear absorption inside transparent and brittle materials, and melts materials at the focal point to realize micro-welding of transparent and brittle media, with high processing precision and small heat-affected zone , unbreakable, high connection strength, and space-selective processing, but this method also exhibits the following problems: (1) Although the ultrafast laser can complete instantaneous welding due to its high energy density at the focus, it is usually used Large numerical aperture microscopic objective lens focuses, the focus space range is small, and the position of the beam remains unchanged. To achieve regional welding, the beam is usually fixed. The precision two-dimensional workbench carries out welding with the movement of the material to be welded, and the processing speed is slow. From the hardware level The processing speed is limited; (2) Ultrafast laser welding usually requires the surface to be welded to be in optical contact, that is, the distance between the contact surfaces is <500nm, and there is no interference fringe when observed with the naked eye. Larger gaps will cause plasma overflow and cause surface ablation or rupture. At present, there is a special experimental research on this, and the maximum tolerance of the gap is required to be within 3μm to be effective for welding. Therefore, this method of welding is not only difficult to apply because it needs to polish and clean the surface to achieve extremely high cleanliness and smoothness. The surface is also powerless and cannot be used in engineering applications. For example, in patent CN106449439A, when using ultra-fast lasers to package glass chips, not only must the surface of the glass to be sealed be maintained at a high level, but also cannot be directly welded when the spacing is greater than 1 μm , it is necessary to add a glass piece between the two pieces of glass, and scan, package and weld the upper and lower pieces of glass and the middle glass piece respectively. The steps are cumbersome and the efficiency is low.

[0004] In addition, there is also a method for welding glass materials with multiple laser beams, such as the method and equipment for welding glass materials with multiple laser beams disclosed in patent CN107892469A. This patent uses ultrafast laser beams and continuous or long pulse laser beams The combination beam realizes the welding of two pieces of the same glass, which can weld the larger welding gap that does not meet the optical contact conditions, and realize the scanning mirror laser welding, improve the efficiency of laser welding, and realize engineering application. However, After research, it is found that the above welding methods still have the following problems: (1) The energy of the ultrafast laser beam and the continuous or long pulse laser beam will be superimposed at the weld during beam combining welding, which will cause the instantaneous temperature of the material to be too high and generate excessive heat. Stress causes poor material strength, so this welding method has high requirements for the selection of laser beam energy, and cannot be applied to higher energy laser beams; (2) Ultrafast laser and continuous or long pulse laser simultaneously Effect, when the ultrafast laser power density is too high, it will cause ablation of the material and affect the welding effect of the material. Therefore, it is necessary to control the power of the ultrafast laser during beam welding, which cannot be applied to higher power lasers.

Therefore, under the limitation of the above-mentioned superposition effect and ablation effect, although it claims that it can realize the welding of two pieces of glass with a contact gap greater than 5 μm, in fact, after research, it is found that it can only achieve the welding of two same materials with a maximum gap of about 12 μm.

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