Design News for Mechanical and Design Engineers

“The core technology is this little tiny bump that literally has less height than a human hair, has less thickness than a human hair and that device can both cool things and generate power,” says Jesko von Windheim, CEO of Nextreme.

The thermal bump used within the OptoCooler is housed in a stage but Nextreme offers its thermal bumping technology without the stage. This allows the bump to be implemented using the standard pillar bumping process already used by companies like Intel, Amkor and Casio.

“Our innovation provides an excepted manufacturing pathway for companies to integrate this technology into their products in a large-scale fashion,” says Windheim.

These solid-state thermal bumps are made of Bismuth Telluride, which according to Windheim has no known toxic effects. The OptoCooler is made up of typical electronics materials including gold, silver and copper and is moving toward lead-free RoHS-compliant production.

Applications for the OptoCooler include cooling laser diodes used in the telecom industry, cooling LEDs, cooling Vertical Cavity Surface Emitting Lasers (VCSELs) and power generation. Specific areas where power generation has applications are within server farms, which produce a lot of wasted heat and for sensors, which typically don’t require a lot of energy to operate.

The OptoCooler and thermal bump technology from Nextreme work best where there is a large temperature differential, typically from a 10-C to 100-C differential. “That’s kind of classical thermodynamics — the bigger the temperature, the better your efficiencies are. However, we have demonstrated devices that can operate with as little as two degrees of temperature differential,” says Windheim.

Future applications for this technology may include scavenging heat from the human body to power medical devices within the body. “That’s very real at this point,” says Windheim. “We haven’t pursued it yet, mainly because we don’t have a clear customer path in that direction yet.”

	The OptoCooler shown here is a fraction of the size of a dime and the thermal bump technology inside is even smaller.