“Fingerprint” technology is the answer
However, the scientists still had one hurdle to overcome before achieving representation on the display: directing the path of the light through the glass fiber to the right position on the display. This procedure is not a problem, for example, when using a mini-matrix with four light points. The glass fiber that receives the light beam at the upper left also transmits it to the upper left of the display, and reproduces the light signal there too. “But even our test model had a matrix of 13 by 17, or 221 points. To connect each single point by hand is complicated and very time-consuming,” explains Streu – and thus too costly. Furthermore, four to six times that number, i.e. between 800 and 1250 image points, were planned for the commercial application. “We had to find another method of correctly coordinating the image points,” says Streu.
Fingerprint technology ultimately offered the solution. “In the first step, a fine light beam is used to determine the path it will take through the glass fiber bundle,” explains Gaydoul. The beam with the entry coordinate A 1 will emerge, let’s say, at G 8. “The arrangement is completely random and because of the large number of glass fibers, different for every unit. That is why it is called a fingerprint.”
Like a puzzle in a mixer