This drop in power enables high-quality, defect-free copper welds to be achieved via heat conduction welding with a blue diode laser, which Pelaprat said leads to a dramatic increase in yield, that in turn reduces the cost of each part produced.
Taking into account the smaller amount of power needed by blue lasers thanks to their higher absorption, Pelaprat envisages that a blue diode laser between 1 and 2kW will be required to process larger thicknesses of copper.
In addition to a blue diode laser with even higher output power, the firm plans to reveal a hybrid laser able to use a combination of blue and infrared wavelengths to weld larger thicknesses of copper.
This is an enormous advantage, as it enables a non-contact tool to be used for this process, so there is tremendous value in using high-power blue diode lasers to weld the foils.' Up to 70 foils can be welded together and then to a copper tab in a single process using Nuburu's blue diode lasers, which can also be used for the welding of copper tabs and busbars at thicknesses up to 0.7mm.
The illumination of the full face hologram was a purpose-built 20mw blue diode laser
, while the two side panels showing Einstein in profile were illuminated with green diode lasers.
The rise of the blue diode laser for material processing has come about because of improvements in gallium nitride wafers from which the diodes are made.
Welding copper with a blue laser can be 10 times faster than with an infrared beam, according to feasibility studies conducted with industrial blue diode lasers that are now being released.
At Photonics West, Nuburu showed a 150W blue diode laser module, the AO-150, which it launched in 2017, while Shimadzu was exhibiting 100W modules.
These are results from the first two years of the three-year Blaulas project, which aims to build a kilowatt blue diode laser. Osram, Coherent-Dilas and the Max Born Institute are all partners.
With a blue diode laser you can do heat conduction welding and get a very nice join.
Blue diode lasers
offer superb beam quality in a compact package and are revolutionizing applications from microscopy to display technology.
High-power direct diode lasers are starting to become an industrial reality, and companies like Nuburu have released blue diode lasers
that emit at 450nm wavelength, rather than the 1[micro]m produced by a fibre laser.