Gratings on glass surfaces
The newly developed method provides a faster and more efficient way for producing gratings - by ablation of small amounts of material - on glass surfaces. Thereby, the economic labeling of glass with patterns causing diffraction becomes possible. These patterns shimmer in different colors if observed from different angles.
Gratings with small distances between the lines cause a diffractive effect and thus shimmer in different colors. This can be used to create aesthetic labels and give the marked product a unique characteristic.
Until now, it was not possible - especially on glass - to produce these structures fast and efficiently enough. For contactless labeling of products, only laser ablation with pulsed lasers can be used. However, conventional laser procedures have several specific disadvantages: glas absorbs hardly any light in the visible range, thus high pulse intensities have to be used. Due to the resulting small laser spots, only tiny areas can be processed per pulse. Plane structuring is therefore only possible on resting workpieces using a scanner. Even though the absorption of infrared light is higher and more powerful lasers are available, the higher wavelength results in lowered resolution of the generated structures - gratings with periods in the micrometer range are not possible. In contrast, excimer lasers combine several advantages for processing of glas surfaces: short wavelengths in the ultraviolet range are well absorbed by glas and plane beam profiles allow for parallel processing of larger areas. Common mask projection techniques can be used for micro-structuring. Mask projection however requires advanced optics and typically used amplitude masks lead to high light losses.
The method was successfully tested with different patterns on different surfaces:
- glas ceramics
Currently, the invention is being further developed in a Federal Ministry of Economics and Technology (BMWi)-funded project (WIPANO - funding focus "public research - further development of inventions"), with regard to industrial manufacturing processes.
DE patent granted: DE102015216342B3
EP patent application disclosed: EP3341153A1
US patent application disclosed: US2018236596A1
CN patent application disclosed: CN107921579A
KR patent application disclosed: KR20180098217A
Patent Applicant: Laser-Laboratorium Göttingen e.V.
J. Meinertz, T. Fricke-Begemann, J. Ihlemann:
Micron and sub-micron gratings on glass by UV laser ablation
Physics Procedia 41, 701 (2013)
J. Bekesi, J. Meinertz, P. Simon, J. Ihlemann:
Sub-500-nm patterning of glass by nanosecond KrF-excimer laser ablation
Applied Physics A 110, 17 (2013)
Dr. Ireneusz Iwanowski
Patent Manager (Physics, Technology and Software)
Tel.: +49 (0) 551 30724 153