Our TOPAZ G is a tailor-made system for layer-side structuring of TCO electrodes on Smart Windows with high throughput and very high resolution.

Managing a tight focus

First of all, it is important to mention that the Smart Window glass pane to be laser structured has a length of more than 3 m, but its thickness is only about 1 mm. An even greater challenge to the patterning process is the fact that the structure width to be produced is sometimes less than 10 µm, with a total tolerance of less than 2 µm over this large glass pane. This is the only way to ensure that the pattern is invisible to the human eye. As a result of this structure width, the theoretical depth of focus of the laser beam at a spot size of 10 µm (1/e²) is less than 150 µm.

To meet these challenges, the glass pane is fixed on a large, flat granite table. In addition, the topology of the granite table is determined and the focus of each patterning head is adjusted accordingly during patterning.

This ensures long-term stable structuring conditions for a sustainable quality of the final product. Remember, the final product is a window and the human eye is not easily fooled.

Two aspects accomplish the required throughput of the TOPAZ G, one is parallelization, the other one is scanning on-the-fly. Parallel scanning is accomplished with of 5 single patterning heads. All of them extremely well calibrated in their own working area as well as with regard to each other and the linear axis system. Scanning on-the-fly means the laser beam is deflected at high speed by a 2D scanner while the axis system moves the patterning head. This mode of operation achieves an unmatched throughput compared to standard step-and-repeat approaches. 

Accuracy and throughput at the next level for a scalable and economical smart window production. The TOPAZ G – a benchmark for large area patterning.