Fraunhofer researchers have now developed a process that allows this key component to be mass produced with extreme accuracy.
Projectors are getting smaller and smaller. Now that pictures are available in digital format almost everywhere, we need projectors to beam giant photos and films onto walls. Projectors contain lenses that spread the light from the pixelated source in such a way as to illuminate the image area evenly. Until now, this was done using complicated arrays of lenses placed one behind the other. Recently, the same effect has been achieved using flat lens arrays made up of thousands of identical microlenses. This kind of array takes up much less space and does not need to be painstakingly assembled and aligned. To date it has only been possible to manufacture these lens arrays from plastic, but the light source in conventional projectors is hot enough to melt them. To get around this problem, Jan Edelmann and his team at the Fraunhofer Institute for Machine Tools and Forming Technology IWU in Chemnitz have developed a process for manufacturing lens arrays from glass, whereby the surface structure of the array is hot embossed into viscous glass at temperatures of between 600 and 900 degrees Celsius.
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