Long Live Lasers

A laser is a miraculous tool that generates a lot of interest in the area of glass processing. And SCHOTT is constantly developing its process know-how. This enables high-precision, customized product solutions that help drive trends, particularly in the area of digitalization.

A laser is a miraculous tool that generates a lot of interest in the area of glass processing. And SCHOTT is constantly developing its process know-how. This enables high-precision, customized product solutions that help drive trends, particularly in the area of digitalization.

Fans of the blockbuster movie Star Wars immediately think of one thing when they hear the word laser: the lightsaber swung by Darth Vader & Co. What fascinates us in fiction has also become a popular constructive tool in the industrial sector. Even while George Lucas was producing his space adventure in the mid-1970s, laser tools had long since become industrial reality: improved CO2 lasers and the development of new types of lasers enabled the first applications in metal-working, especially in the automotive and aircraft industries.

“It took a while for lasers to be used in glass processing,” explains Bernd Hoppe, Head of the Competence Field Laser and Post Processing at SCHOTT. “In the meantime, they have become robust, reliable and economical. When it comes to specialty glasses, they do an extremely good job, with highly reproducible results in 24/7 use, high flexibility and no wear and tear.” The process engineer knows what he is talking about. He has been working intensively on glass-based laser processes for over two decades and is a stake-holder in over 75 patents on novel glass processing technologies. His 15-member team of experts works on development projects that involve the use of lasers – from the initial process idea to the successful transfer for use in serial production.

The infrastructure in the so-called experiment hall of the research center is always kept up-to-date. For the last few months, it has also housed a glass processing facility with the most powerful commercially available ultrashort pulse laser for industrial applications. This is used to develop particle-free cutting processes, flexible structuring processes and innovative optical concepts or glass processing. The processing area of the system is 600 x 1,200 mm. “We achieve extreme specifications with the new tool. More specifically, tolerances of ten micrometers or less,” explains Michael Kluge, the person responsible for the facility and Project Manager for Post Processing. His job is to make the production technology of the laser tools that are available on the market accessible to SCHOTT for use in glass processing, to develop it further and ensure that it is ready for use in development projects.

Laser-Glass Interaction

Conventional cutting and scribing of glass cause splinters and particles, while breaking causes chipping along the edges. The diamond tools used to wear down and then have to be replaced. Furthermore, customized products require a complex and time-consuming process sequence. On the other hand, laser processes offer many advantages: Complex geometries can be realized in a short period of time simply by reading the design drawing directly into the machine. The non-contact tool works without leaving any particles behind, is dry and requires no additional aids. During cutting, the glass is first perforated or ‘damaged’ locally and then separated by way of thermal cleaving. SCHOTT has several high-performance ultrashort pulse lasers as well as CO2 lasers of various power classes that are used not only for cutting but also for structuring, marking, decorating, forming and bonding.

There is no universal recipe for the optimal interaction of glass and lasers for all glass types, however. What counts is experience, coupled with specific technological and material know-how. “With laser-based processes, we achieve new, improved glass functionalities and properties that would be completely unthinkable without lasers. We are thus exceeding the technological limits of conventional processes,” explains Bernd Hoppe. “Our unique selling point is our continuously optimized process know-how for a broad portfolio of specialty glasses. And customers benefit from this.“

Using the ultrashort pulse lasers, SCHOTT is perfectly prepared for the next technology leap: high rate structuring.
The structured glass wafers achieve tolerances of 10 micrometers thanks to laser processing.

Revolutionary Solutions

Besides dead-front effects for special light displays in cooktops that are created by structuring, the forming of light conductors for dental applications, glass plates with precise laser-drilled holes for showerheads, sophisticated structured flat, thin and ultra-thin glass wafers with tolerances of less than 10 micrometers and high edge qualities are particular highlights of the laser processing that SCHOTT performs. They are suited for innovative electronic, semiconductor, diagnostic and medical glass solutions.

The pharmaceutical industry also benefits from SCHOTT’s know-how. The introduction of Smart Containers makes it possible to tap into the power of machine vision and mass data analysis on pharmaceutical filling lines. Each Smart Container is marked by laser with a unique identifier to enable the first time complete traceability throughout the entire manufacturing process. The data matrix code is as small as 1 x 1 mm. The technology can be used o improve line clearance, reduce the risk of mix-ups, and reduce targeted container-based recalls. “We are ushering in a new era of digitalized pharmaceutical production that focuses on real-time approvals and utilizes the latest developments in machine vision and data science,” comments Diana Löber, Global Product Manager for Vials.

Ultrashort pulse lasers also offer new possibilities for the joining of glass wafers without the use of any adhesives. This enables hermetic sealing with new material combinations. “With glass micro bonding, we have a pinpoint sealing area with a minimal thermal load of just a few microns. We can create a hermetic seal without subjecting the component or electronics to be encapsulated to potentially damaging heat, and without the need for any additional materials,” explains Ville Hevonkorpi, the Finnish Managing Director of SCHOTT Primoceler Oy.

Glass micro bonding technology enables room temperature processing without warpage or out-gassing. “The benefits of our laser welding process are multiplied when using thinner materials and bigger wafers, which is well aligned with current development trends,” Hevonkorpi adds. The process is suited for near-perfect gap control in microfluidics, glass-based hermetic lens positioning in micro-optics, VCSEL arrays in aerospace, and 3D chip packages for semiconductors. In combination with biocompatible glasses, solid glass housings make it possible to realize highly miniaturized medical implants – many of which are orders of magnitude smaller than current implants and enable entirely new medical applications.

High rate structuring

The high-performance levels now available prepare the laser for the next leap: ultra-fast processing of large surfaces. This is achieved by special beam shaping and parallel laser beams with only one laser source. By using large format optics, square-meter-sized glass plates can then be processed and structured in seconds. This opens up new functionalities, faster structuring processes and decorative applications. As Hoppe puts it: “High rate structuring is a trend and currently one of our new focus topics. We are at the forefront of technological evaluation and maintain a large network with external partners in order to implement the technology as quickly as possible.”

In the new star saga by film producer J.J. Abrams as well, the lightsabers have not only developed in terms of color but also technologically, after 42 years: In the latest Star Wars episode 9, a folding red double lightsaber was even used for the first time. And at the University of Würzburg in 2018, Professor Dr. Tobias Brixner and his ‘Femto Stars’ from the Faculty of Physical and Theoretical Chemistry, took a closer look at the fictitious fencing weapon and realized a lightsaber based on femtosecond laser pulses.

December 9, 2020


Bernd Hoppe
Research & Development