The quality of home printing has steadily increased since Hewlett-Packard launched the first consumer inkjet printer in 1984, with resolutions many times higher than that original model. But imagine the high resolution needed to produce a full-colour print that would fit inside a human hair. That’s exactly what Swiss researchers have achieved, scooping a new world record in the process. In a joint venture between ETH Zurich University and their startup company Scrona, an exciting new technology was used to produce a photograph with an amazingly small area of 0.0092 square mm — that’s roughly the size of just one pixel on a retina display. The resulting picture is of clownfish in a sea anemone, a suitably vibrant choice to show off the vivid and lifelike 24bit depth of colour. One small problem, though: the print is so tiny, it can’t be seen with the naked eye! Guinness World Records witnesses had to use a microscope to check the photo and verify the world record claim.
The technique used to create the record-breaking print, called 3D NanoDrip, is similar to the way in which inkjet printers operate. Instead of dots of ink being fired onto the paper, however, 3D NanoDrip uses quantum dots. Quantum dots are tiny particles that emit a bright light, the colour of which depends on their size. The researchers are able to adjust the size of the dots very precisely so that they are able to control which colour each one appears. They are then applied to the printing material in layers of red, green and blue to build up the colours of the image, at an incredible resolution of 25,000 dots-per-inch. This means that the quantum dots are printed just 500 nanometres apart. Up until this point, it had not been possible to deal with quantum dots accurately enough to place them with the precision required in order to use them to print clearly. This new advancement opens up many possibilities for research into other uses for them.
The Bigger Picture
Although it may seem like printing a picture this small might have little more use than to show off that it’s possible, quantum dots do have another use — in television sets. Companies such as Sony, Samsung and LG have already demonstrated TVs which use quantum dots, as the amazing particles allow bright, intense colours to be displayed on screens. In the future, we are likely to see increased use of ‘nanostructured’ materials in various applications. In particular, it seems that quantum dots lend themselves very well to display-related technologies. Scrona themselves aimed to attract funding via a Kickstarter campaign, where they were offering buyers the chance to have their very own micro-printed images. Just so any takers could be sure they weren’t getting ripped off, the prints were offered complete with a miniature microscope so they could actually be seen.