Which is
the highest resolution that can be obtained for colour printing?
It is
determined by the diffraction limit of visible light, and it requires colour
elements (pixels) with a pitch of 250 nm. That is, a resolution of
~100,000 dots per inch (d.p.i.). For a comparison, inkjet and laserjet printers
have a 10,000 d.p.i. resolution. The highest
resolution limit was recently achieved by a research group from the Agency for
Science, Technology and Research (A*STAR) in Singapore.
The study,
published online in Nature Nanotechnology, illustrates the
method that was used to achieve the highest possible resolution limit for
printed colour images.In the used
technology, colour information is not encoded in colourants or dyes, but in the
dimensions of metal nanostructures: by
changing in the diameters of the elements and the distance between them it is
possible to modify the colour of light they reflect. Each pixel
consists of nanospots capped with silver and gold nanodisks. The researchers
were able to obtain a full palette of colours that span the visible range by
varying the diameter and the spacing of these nanodisks.
The
printing method could be used to create microimages or secret messages for
security, and to make discs able to store high-density data.
by VALENTINA DAELLI - Science Communication, Neuroscience