Femtosecond laser glass welding

With the development of the 3C industry and the miniaturization of components, the realization of micro-connections between components to ensure high density and high reliability of products is an urgent problem in the industry. Lasers have been widely used to solder various materials, but there are still challenges to micro-joining between glass materials. Although traditional glue bonding can realize the connection between various materials, its aging, pyrolysis, and thermal expansion are difficult to ensure the reliability of the product. At the same time, laser welding has been widely used in industrial production, but the energy of ordinary long pulse laser is not easily absorbed by glass and thermal expansion easily breaks the glass, and is not suitable for transparent materials such as micro-welding glass. The ultra-short pulse laser interacts with transparent materials with the characteristics of small thermal effect and nonlinear absorption. It is very suitable for micro-welding of transparent materials. At present, high-strength glass welding has been achieved by using femtosecond laser.  

The principle of femtosecond laser glass welding is to focus the high-intensity femtosecond laser on the interface of two transparent glass materials. The glass at the interface undergoes melting and re-condensation, and finally the two glasses are firmly combined. Since the absorption of the femtosecond laser by the glass material is a nonlinear absorption, the laser processing region is only limited to the vicinity of the focal region, and at the same time, the time during which the laser pulse acts on the glass material is on the order of femtoseconds, so that the thermal effect is obtained during processing. Significantly reduced, avoiding cracking of the glass material due to thermal expansion. By properly controlling the laser power and repetition frequency, precise control of the size of the molten pool can be achieved, resulting in higher welding strength. At present, the femtosecond laser has been able to achieve welding between various glass such as borosilicate glass, aluminosilicate glass, soda lime glass, and the welding strength is close to the original strength of the glass.


Huaray's self-developed stable and reliable femtosecond fiber laser HR-Femto 50-10, which provides single pulse energy up to 50 μJ and repetition rate up to 5 MHz, with a pulse width of less than 350 fs, is suitable for most glass materials. Ensure sufficient machining accuracy and welding strength.