Waveguide, grating design improves near-to-the-eye smartglass display

Dispelix Oy, a spinoff of research organization VTT Technical Research, has developed a see-through, near-to-the-eye smartglass display that uses novel waveguide-based optics to transfer a virtual image into the eye of the user.

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Dispelix Oy (Espoo, Finland), a spinoff of research organization VTT Technical Research (also in Espoo), has developed a see-through, near-to-the-eye smartglass display that uses novel waveguide-based optics to transfer a virtual image into the eye of the user. Because the optics are thin and transparent, the technology can be implemented in what looks like standard eyeglasses and can project images from liquid-crystal-on-silicon (LCOS), light-emitting diode (LED), liquid-crystal display (LCD), and laser-based image sources, without anyone knowing that the user is viewing a virtual screen that appears as large as a 60 in. television viewed from a distance of 3 m to the eye.

"The projection optics are integrated into the glasses and the projected light is coupled into a 1–2 mm thick light guide by a high-efficiency incoupling grating," says Antti Sunnari, managing director at Dispelix Oy. "The incoupled light propagates in a high-refractive-index light guide via total internal reflection until it encounters a patented outcoupling grating that has high see-through transparency [60–70%] and doesn't produce any optical aberrations. The view through the grating to the surrounding world is crystal-clear without any haze or rainbow patterns and the laterally wide out-coupling grating expands the eye-box in the horizontal direction, providing good user experience for all users despite their varying interpupillary distances."

Contact Antti Sunnari atantti.sunnari@dispelix.com.

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