From sci-fi to the supermarket - 3D holograms
A development in holographic imaging means that supermarkets could one day end up looking like scenes from Hollywood film Avatar.
Scientists in the USA have worked with Japanese company Nitto-Denko to develop a material that can be used for full-colour display of holographic images. The visuals can be seen without 3D glasses and can refresh in seconds. This could have implications for interactive packaging.
‘A large variety of packages for commercial products already use holography to make the products more attractive,’ says Pierre Blanche, Assistant Research Professor at the College of Optical Sciences at the University of Arizona, ‘but [with this display] you see the product in 3D with different layers.’
After being photographed from a dozen angles, the image is stitched together on computer from holographic pixels (‘hogels’) and is ‘written’ into a sensitised photorefractive polymer material using a fast-pulsing laser beam. Although the surface is 2D, the image is ‘stereoscopic’ and can be viewed from different angles giving the illusion of depth, while full-colour is achieved using angular multiplexing. ‘Your eyes see two different images wherever your position is,’ says Blanche.
Holograms typically use materials such as silver halide or dichromated gelatin, but once recorded they are permanent. ‘That’s what has existed for the last 30 years,’ he says, ‘but now the image becomes dynamic, more like a TV rather than a poster.
Holographic cinematography has been done before but previously the recording media had to be processed after exposure, causing a delay in the visuals. By engineering a photorefractive polymer material, the Arizona team claims to be able to create a 17-inch display unit that can produce a new frame every two seconds. This greatly improves on previous crystalline materials that could only refresh every few minutes, and paves the way for a holographic display that features moving images at video speed.
Blanche says that the team should have a commercial product available within the next couple of years. Further research is needed to make the material refresh faster and faster and consume less energy in laser writing the hologram.
However, Glenn Wood, of the International Hologram Manufacturers Association foresees the technology on point of sale displays rather than the packaging itself, as the cost and size of the equipment used to power the hologram and the laser would present a challenge to any packager wanting to implement moving holograph images. He suggests that if at all, it would only appear on luxury packs. ‘It would be a very expensive item, not to mention the 50,000v that needs to be applied to the screen to make it work.’