3D laser printer for small-volume glass nanomanufacture
A new European project, starting this month, aims to design a desktop 3D laser printer that will print microstructures in glass, taking the manufacture of microsystems out of the cleanroom.
Microsystems are minuscule machines, hardly visible with the naked eye. They often contain both mechanical and electric components and are used to measure signals, or to drive components. Increasing numbers of devices contain microsystems, such as the accelerometers in laptops which detect immediately when the laptop is falling and ensure that the hard disk is prepared for a shock, thus preventing loss of data. Another well-known microsystem is the so-called lab-on-a-chip, which can test a drop of blood, urine or saliva for pathogens or drugs.
However, the development of microsystems has been slow because building them requires large, expensive and energy-hungry machines and a special cleanroom, said project co-ordinator Dr Yves Bellouard, of the Department of Mechanical Engineering at Eindhoven University of Technology. He said that the investment required to make microsystems has shut out smaller, more innovative companies, and made it profitable to address only those applications that need large numbers of devices.
The new project, called Femtoprint, will instead use a femtosecond laser to write 3D patterns in glass. The properties of the glass - in particular, its refractive index - change in the areas exposed to the laser, allowing its light conductivity to be adjusted. This could be used to build optical computer chips, say, or optical motion sensors.
In addition to the optical properties, the laser can also influence the chemical properties of the glass, particularly its sensitivity to acids. The applied three-dimensional pattern can simply be etched away in one go, whereas conventional methods still build up the patterns layer by layer. And as the pattern is applied in the interior of the glass, there is no contact with the air, so there is no cleanroom required. Bellouard and his colleagues have already proved that this method enables them to make the basis for a lab-on-a-chip.
A major goal of Femtoprint - which has won almost 2.5 million Euro of support from the EU - is to reduce the laser, which currently occupies a laboratory table, to the size of a shoebox. French laser manufacturer Amplitude Systèmes will be responsible for this part of the project. There are a number of British, French, German and Swiss partners involved as well. Bellouard’s group will focus mainly on researching the effects of the laser light on fused silica, the high-grade glass that is used for the microsystems.