DPSS Lasers Overcome Glass Process Challenges 3
A much larger market for glass processing is flat panel device (FPD) and touch sensor panel (TSP) manufacturing. Consumers worldwide continue to embrace and integrate smartphones and tablet devices into their lives, and this will no doubt drive a need for tools to manufacture ever-more complex shapes and structures in glass. The glass used for these devices is relatively thin and likely to get thinner. With the unveiling of various surface-strengthened glasses such as Corning Gorilla Glass and Schott Xensation �C not to mention the likelihood of further innovation �C glass thicknesses are expected to decrease sharply from the current standard of 0.3 to 1.1 mm to perhaps no more than several tens of microns.
Figure 2. Nanosecond-pulse Q-switched lasers can cut closed-shape geometric figures in strengthened glasses. Here, a 5-mm-diameter through hole has been cut in 1.1-mm-thick Gorilla Glass for smartphone production. Cutting time is ~15 s.
Although the need for glass processing in the FPD/TSP markets is large and growing, it is at the same time unclear exactly which laser technology can meet the quality and throughput demands. In some cases, nanosecond-pulse Q-switched lasers have been used to cut closed-shape geometric figures in such strengthened glasses (Figure 2). Compared with the previously highlighted marking application, power requirements are much higher; in this case, a Spectra-Physics Pulseo 355-20 laser system that delivers <20-ns pulse durations, pulse energies above 200 µJ and 100-kHz repetition rates was used.
The high laser power results in reasonable throughput; however, the as-cut edge quality can be good but imperfect. Depending on the exact details of an application's demands, some postprocessing steps such as chamfering/polishing may be required. In some applications, these added steps are undesirable. Perhaps a more finesse-oriented laser �C for example, a high-power and high-pulse-repetition-frequency femtosecond-pulse laser �C could be the right solution. Indeed, this class of laser offers high-quality structuring of glass materials with excellent surface and edge quality for precision processing (Figure 3).
Figure 3. A high-power, high-pulse-repetition-frequency femtosecond-pulse laser offers structuring of glass materials with good surface and edge quality. Here, 3-D glass structuring has been performed with a Spectra-Physics High Q femtosecond laser.