Laser Projection
Posted August 25, 2009
By admin
How does the pattern projection (laser) in virtual keyboards work?
Hi,
Does anyone know specifically how does the laser diodes project keyboard images onto the surface (like for i-tech's)? Like, what equipment they use --> laser diodes, convergent lens (??)... Also how did they manage to project such images onto surfaces.
Thx
Usually is is done with a diffractive optical element (DOE). This is a thin piece of plastic or glass that has ridges pressed or cut into it. These ridges are arranged in a very specific pattern called a phase mask. When collimated, coherent light (think laser) passes through the plastic, it is bent by diffraction into the pattern you see projected on the surface.
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