Societal pressure to renewable clean energy is increasing which is expected to be used
as part of an overall strategy to address global warming and oil crisis. Photovoltaic energy
conversion devices are on a rapidly accelerating growth path driven by government, of which the
costs and prices lower continuously. The next generation thin-film devices are considered to be
more efficiency and greatly reduced silicon consumption, resulting in dramatically lower per unit
fabrication costs. A key aspect of these devices is patterning large panels to create a monolithic
array of series-interconnected cells to form a low current, high voltage module. This patterning is
accomplished in three critical scribing processes called P1, P2, and P3. All-solid-state Q-switched
lasers are the technology of choice for these processes, due to their advantages of compact
configuration, high peak-value power, high repeat rate, excellent beam quality and stability,
delivering the desired combination of high throughput and narrow, clean scribes.
The end pumped all-solid-state lasers could achieve 1064nm IR resources with pulse width of
nanoseconds adopting acoustic-optics Q-switch, shorter than 20ns. The repeat rate is up to 100kHz
and the beam quality is close to diffraction limit. Based on this, 532nm green lasers, 355nm UV
lasers and 266nm DUV lasers could be carried out through nonlinear frequency conversion.
Different wave length lasers are chose to process selective materials. For example, 8-15 W IR
lasers are used to scribe the TCO film (P1); 1-5 W green lasers are suitable for scribing the active
semiconductor layers (P2) and the back contact layers (P3). Our company, Wuhan Lingyun
Photo-electronic System Co. Ltd, has developed 20W IR and 5W green end-pumped Q-switched
all-solid-state lasers for thin-film solar industry. Operating in high repeat rates, the speed of
processing is up to 2.0 m/s.