Highly integrated near-to-eye display and gaze tracker

We have developed a Near-to-Eye Display (NED) technology based on diffractive optics. Thin and highly transparent plastic light guides enable a light-weight and ergonomic see-through NED design. We have previously reported of a compact NED with an integrated gaze tracker. Eye gaze tracker can detect the user's focus point in the displayed image. We have now made advances to further increase the level of integration as well as to enable the optical see-through. Originally, three separate light guides were used: two for the display (red, green/blue) and one for infrared light of the gaze tracker. To reduce weight and the system complexity, a shared light guide is now used for transmitting red (similar to 630 nm, display) and infrared (similar to 850 nm, gaze tracker) wavelengths. In addition, shared output gratings are used for out-coupling the light. Light guide plates have been characterized by measuring their modulation transfer functions. Measurements show that the deterioration of the NED's resolution, caused by the light guides, is reduced with improved manufacturing techniques. Also, it has been verified that the additional gratings for infrared (light in-coupling and expansion areas) do not have a notable effect on the display resolution.