Holography harnessed to improve heads-up displays

Researchers at the University of Arizona have used holographic optical elements to create heads-up displays that deliver information even when viewers move around or aren’t positioned in an expected field of view.

The researchers define heads-up displays as: “transparent devices used in airplanes and cars to provide information such as critical flight data or driving directions on the windshield”. Their new approach expands what they describe as the “eye box”.

A small eye box means that information partially or wholly disappears if the viewer shifts their gaze too much. Pierre-Aleandre Blanche of the University of Arizona, said: “A heads-up display using our new technology installed in a car would allow a driver to see the displayed information even if he or she moved around or was shorter or taller than average.” 

The research, published in The Optical Society journal Applied Optics, demonstrates a functional prototype heads-up display that uses holographic optical elements to achieve a larger eye box than currently achieved.  

Colton Bigler, first author and a doctoral student in Blanche’s laboratory, said: “Increasing the size of either the eye box or the displayed image in a traditional heads-up display requires increasing the size of the projection optics, relay lenses and all the associated optics, which takes up too much space in the dashboard.

“Instead of relying on conventional optics, we use holography to create a thin optical element that can be ultimately applied onto a windshield directly.”

“We are working with Honeywell to develop these displays for aircraft, but they could just as easily be used in cars,” Blanche said. “Our approach requires no expensive equipment and no new materials need to be developed. Furthermore, the display can be completely integrated into a standard car windshield.”

“It’s possible to create a much larger eye box by increasing the size of the injection and extraction holographic elements, the only limitation is the size of the glass displaying the image,” Blanche continued. “Our work is a good example of how holography can be used to solve many types of optical problems for various applications. A similar approach might also be useful for augmented reality headsets, which also merge computer-generated images with views of the outside world but with a display that is close to the eye.”

The researchers demonstrated their approach using one colour but say that it could be expanded to create full-colour heads-up displays. They are also working to use the same approach to create a much larger image that is extracted by the holographic element to increase the size, or field of view, of the display.

[Via OSA]

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