POSTECH and Samsung Research Build AR Glasses Bright Outdoors

Why AR glasses struggle

Conventional AR glasses send light from a tiny display into a thin waveguide, where surface microstructures redirect it toward the eye. Some of that light escapes in other directions, lowering brightness, and the loss grows as the field of view widens. Narrow viewing angles, low brightness and thickness are among the long-standing complaints, along with weight, battery life and heat.

The researchers arranged nanostructures smaller than the wavelength of light on the waveguide surface. Their shape and spacing vary by position, so the light's direction is controlled according to where and at what angle it enters. For full color, they combined one layer carrying mainly blue and green with another carrying mainly red and green. Each layer uses a silicon nitride (SiNx) metasurface with 29 differently designed nanostructure regions.

Measured results

According to Rho, the optics are 1.5 mm thick in total and offer a 30-degree diagonal field of view. With 15 mm between eye and waveguide, the eyebox measures 8 mm by 8 mm. Across eye positions, white-light luminance efficiency at the image center averaged 1,938 nits/lm and peaked at 4,225 nits/lm. Average efficiency for red, green and blue was 1,897, 1,977 and 2,170 nits/lm, which the team calls relatively balanced.

In indoor and outdoor shots, the prototype showed white text in bright outdoor light and color images indoors with display output cut to 30%.

Next steps

Rho said improving image quality so small text is easier to read in bright sunlight remains a follow-up task. He added that scaling production to large-area nanoimprint processes could replicate the nanostructures precisely over wide areas, lowering costs and raising productivity.