A 3D Stereoscopic Head-Up Display (HUD) using a tunable bandpass filter for L/R separation

What is it about?

A 3D Stereoscopic Head-Up Display (HUD) using a tunable bandpass filter to perform left and right image spectral separation is presented. Using a single filter reduces the size and the cost of the HUD optical engine, and enables each spectral band to be accurately tuned. Experiments performed on the first prototype demonstrates the ability to continuously tune the bandpass frequency on 30 nm range while keeping a 20 nm bandwidth. Such a system avoids the use of a bulky and costly rotating wheel and enables the use of Holographic Optical Elements known to be wavelength selective.

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Why is it important?

A new HUD architecture was presented, using a tunable filter. The capability to accurately tune the wavelength of the two images for a stereoscopic projection is of great value, allowing the blue shift compensation of the goggle filter in case of wide viewing angle. Additionally, if diffractive or holographic optical elements need to be used, fine adjustment of the spectral source by means of the tunable filter is a great improvement, drastically reducing frequency crosstalk on 3D display. Even if this first study shows a monochrome application, a triple bandpass filter could be used to display a 3D image by multiplexing the two sets of Red, Green, Blue colors.