The art of walking through walls made real

Academy of Finland showed the way at Science Exhibition
The art of walking through walls made real

Walking through walls has just become possible. Senior researcher Ismo Rakkolainen and Professor Karri Palovuori from Tampere University of Technology have pioneered a fog display that is physically penetrable. A prototype of the screen was introduced to the public for the first time at the Academy of Finland stand at the Turku Science Exhibition on 4-6 October 2002. International patents are now pending on the innovation.

There are endless potential applications for the fog display. Among the examples mentioned by the researchers are the projection of images in art exhibitions as well as in advertising and gaming applications and in theme parks. The technology allows for the creation of extremely large surfaces and entices the audience into experimenting.

The key lies in the laminar airflow

The fog display consists of a laminar, non-turbulent airflow into which a thin fog screen is injected by means of separate nozzles. Together, the fog screen and the protective laminar airflow create a thin and crisp surface. A vacuum system can be used to remove humidity, and to ensure non-turbulence or to improve non-turbulence, but this is not necessary. Both film or still images can be projected onto the fog display, creating for instance swiftly flowing rapids or a brick wall. This means you can indeed walk straight through the wall, without breaking sweat. As well as fully penetrable, the fog display is non-poisonous, non-breakable and extremely light weight.

Early versions out of drinking straws and banana boxes

‘I knew about a few other fog screen methods, but they were all highly unreliable. I began to apply myself to the question of how we could create a better and more reliable mechanism. I talked about this with Karri Palovuori, and we soon produced the basic parameters for our idea,’ Ismo Rakkolainen says. Both Palovuori and Ismo Rakkolainen work at the Tampere University of Technology Signal Processing Laboratory.

Initially Ismo Rakkolainen wanted to keep his blueprint for the screen close to his chest, so he began working on the idea in his own living room. At this stage funding for the innovation was not yet forthcoming, so the very first versions were created using banana boxes and 2000 drinking straws. His wife, not surprisingly, had some doubts as to how serious a scientific exercise this was.

The prototype on display at the Academy’s stand in Turku is a more advanced version, standing almost 1.5 metres high. Mika Piirto from Tampere University of Technology has spent much of the summer working to further improve the mechanism, under the supervision of project director Ismo Rakkolainen.

An even more advanced model of the screen will be on show next year at Museum Centre Vapriikki and at the Communications museum in Tampere.