Lasers become more and more popular in production of various solar cells finding application in such technologies like:
Edge Isolation,
Vias Drilling,
Patterning in Thin-Film cells (P1, P2 and P3 structuring),
Edge Delete in Thin-Film cells,
Marking,
and bringing increasing the productivity, quality and other features in production process.
Performance of above mentioned laser technologies can be seriously improved by applying the Laser Beam Shaping technique, for example, transformation of a beam intensity profile from Gaussian to so called flattop (uniform) distribution. This optical transformation helps to improve a trench profile in sense of steeper walls and reaching flat bottom, reduce drastically the HAZ (heat affected zone) and increase the productivity of material processing due to more efficient usage of the laser energy, see the details here.
Just this transformation is realized by the refractive beam shapers Focal-piShaper - intended to work with lasers of different wavelengths and create flattop, donut and other intensity distributions for beams focused by a diffraction limited lens to spots below 100-200 micron.
The group of Focal-piShaper models is a part of a family of refractive beam shapers realizing so called field mapping optical approach and having the trade name piShaper.
Intensity profiles of focused beams under various F-piShaper settings (Courtesy of Altechna, Lithuania)
Input beam diameter 6 mm
Input beam diameter 4.2 mm
Animated presentation of intensity profile behaviour in zone of focal plane of a diffraction limited lens can be seen by clicking on the corresponding picture.
The operational principle presumes applying of a focusing lens after the Focal-piShaper. There can be a lens of any type: an F-theta lens, any kind of telecentric lens or focusing lens.
The most important feature of the lens is that it has to be diffraction limited one, in other words, it shouldn’t implement any wave aberration over whole working field. This is an essential condition for proper operation of the Focal-piShaper.
Effect of applying an Focal-piShaper in laser scribing technologies is illustrated on below pictures showing results of scribing of glass with a short-pulse laser, wavelength 1030 nm.
Comparison of scribing the glass (Courtesy of Altechna)
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