Philips has developed a magnetically levitated positioning stage that has six degrees of freedom and can deliver nanometre precision. The free-floating Planar Maglev platform (shown below) is supported by a combination of coils in a stationary bed and permanent magnets embedded in the platform.

The technology can produce linear displacements of around 0.5m in the X and Y axes, and 1mm in the Z and rotational axes. It is controlled by software which has taken almost a decade to develop. The software constructs a model of the system from sensor readings and then computes the forces needed to move the platform to a new position.

By shifting the system`s complexity into software, Philips has been able to make the planar motor less mechanically complex than conventional multistage precision positioning platforms — as well as potentially less costly to manufacture.

The maglev technology avoids the cables, cooling hoses and other mechanical connections typical of existing bearing-based platforms.

Peter Frissen, Philips` project leader, describes the software as "the key enabler that allows both relatively simple mechanics to be used in the inverted planar design, and manoeuvrability with six degrees of freedom to nanometre precision".

Initial applications are expected to be in high-tech areas such as semiconductor production, where the stages will allow wafers to carried though several processing steps without having to transfer them from one platform to another. Limiting the number of times a wafer is handled should improve accuracy, processing times, and yield.

Philips predicts that the technology could also have applications in other areas such as laser machining, materials research, pharmaceuticals, and food production.

According to Prof Jan van Eijk, Philips Applied Technologies` chief technology officer, the development means that "magnetic levitation now provides a technology that`s mechanically simple and inexpensive to manufacture, is clean, has no wearing parts, and can be positioned with accuracy down to tens of nanometres or less."

Philips has produced a demonstration version of the Planar Maglev technology. It hopes that this will stimulate and aid discussions with potential partners and co-developers.