Optics takes a big step towards getting smaller

Trimo was developed by researchers from Leica Geosystems and the Department of Robotic Systems Keystone Archive

Miniaturisation in the field of optics has been given a boost by a new device invented by Swiss researchers.

Unlike transistors, which have long been miniaturised and assembled by machine, optical elements must still be packaged and assembled by hand because of the high degree of precision needed for them to function properly.

But that is soon to change with the advent of new technology, dubbed Trimo, which automates the assembly and the picking, placing and fixing of micro-optical elements on a board with the required level of accuracy.

It is designed to work with the newest optical components which now measure no larger than 1.5mm using methods derived from the electronics industry, namely surface mount device techniques.

Trimo was developed by researchers from Leica Geosystems and the Department of Robotics Systems at the Swiss Federal Institute of Technology at Lausanne (EPFL).

The team, led by Leica’s Alain Würsch, 26, was given the 2001 Nortel Networks Prize for the invention of Trimo, without which it would not even be possible to handle these newly created, tiny photonics parts, much less place and fix them on a circuit board. The optical elements involved measure less than a millimetre in size.

Manufacturing potential

“Many researchers at universities and in industry have been working on miniaturizing optical components but they have neglected to consider how to manufacture them,” says Bernhard Gächter, of Leica Geosystems, the lead researcher in the project.

The Trimo technology is housed in a robotics workstation where tiny pincers pick up the optical elements and place them in exactly the right spot so that they can be affixed in the same way that transistors, for example, are picked up, placed, and soldered onto a board in an electronics factory’s production line. Only this is an order of magnitude smaller.

“There is no single element about the development that was radically inventive,” says Christoph Harder, director of Device and Technology Development at Nortel Networks Optical Components (Zurich), which sponsored the prize. “Rather what makes it innovative is the novel way that robotics and micro-mechanics were combined in a tool that lends itself to automation.”

The discovery is the result of a Swiss government funded research project that began ten years ago. Leica engineers worked with university researchers to ensure that new miniaturised optics being designed in Lausanne could also be produced in volume.

Strong demand

There is a strong demand in the photonics industry for robotics tools such as the one developed here, says Lee R Irvine, an electronics packaging consultant who is also an editor at Chip Scale Review. “A high quality machine that truly has the accuracy, is user friendly, and also has the productivity needed and would be a significant improvement.”

The drive towards miniaturization is pushing the photonics industry closer and closer to the kind of breakthroughs made almost half a century ago in the electronics industry.

“The miniaturization technology we developed will have a great impact on the photonics market,” says Gächter. “The leap that is about to be made due to optical miniaturization is analogous to the leap made in the electronics industry when 100mm radio tubes were replaced by integrated circuits.

“We can now go from optics that measure 60mm in diameter to elements that are smaller, about 1mm in size, and that have a greater functionality than the bigger units.”

The contest was organised and run by the Swiss Society of Optics and Microscopy, an association of optical researchers and engineers. The Nortel Networks Prize is to be awarded every two years and is worth SFr5,000.

by Valerie Thompson