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Laser Edge Deletion

Removing all Coatings on Thin-Film Solar Cells

For electrical isolation and hermetic sealing of the modules, the complete ablation of all layers from the edges of fully processed thin film solar cells on glass substrates is required. In order to meet the required throughput rates of modern production lines, the laser edge deletion process must achieve ablation rates in the range of 50 cm2/s. Other possible conventional methods are sand blasting and grinding.

 

Since standard TEM00 lasers like Nd:Vanadate lasers for scribing do not provide the necessary ablation rates for edge deletion, especially developed q-switched high-performance  lasers are applied. These diode pumped Nd:YAG lasers providing an average power of up to 850 watts at 30 kHz achieve a homogenous, top hat intensity profile with a 600 micron thick step index fiber. Typical ablation widths range from 0.7 to 1.5 mm at processing speeds of up to 6,000 mm/s.

 

Laser Edge Deletion with Square Optical Fibers

Laser Edge Deletion with Square Optical Fibers

As ablating is a pulsed laser process, a square spot geometry provides the benefit of a consistent overlap of individual pulses. New square optical fibers create these homogeneous square laser spots. Compared to round optical fibers, the surface volume can be increased by max. 51 %. The square geometry allows significantly more efficient and homogeneous overlap geometries for larger surfaces.

 

For laser edge deletion we recommend: DQ SeriesHighLight FL1000P