Waveguide KPIs
Over years of waveguide development, we have measured everything from sharpness, brightness, and contrast to image quality and light engine compatibility. We continue to measure these important factors, but we have found that four optical attributes consistently emerge as the strongest indicators of performance: Transmission, Reflectivity, Uniformity, and Efficiency.
Together, these characteristics form the foundation of our waveguide KPI system, TRUE.
Transmission
Transmission measures how much light from the physical world can pass through the optics to the user’s eyes. Since digital content is layered onto the user’s environment, maintaining a clear and natural view through the lens is critical.
A strong transmission value means the user’s surroundings appear crisper and brighter, which supports wearability, situational awareness, and eye comfort.
Lower transmission can make the user’s environment appear darker, reducing visual comfort and making digital content harder to see in different lighting conditions.
Reflectivity
Reflectivity refers to how much light reflects off the waveguide instead of passing through it.
Low reflectivity helps the lenses look clearer, more transparent, and more like traditional eyewear.
When reflectivity is high, the lenses may appear overly mirrored or dark, giving the appearance of sunglasses, which can feel intrusive during social interactions.
Uniformity
Digital content needs to remain consistent across the display for virtual images to feel stable and natural. Uniformity affects brightness, color, contrast, and sharpness, from edge to edge of the waveguide.
Strong uniformity helps improve readability, reduce distractions, and create a smoother viewing experience as users move through different environments and lighting conditions or shift their gaze across the display.
Poor uniformity can create bright spots, dim regions, uneven colors, and visible artifacts like rainbows. These inconsistencies can contribute to eye strain and reduced visual comfort.
Efficiency
The more efficiently a waveguide operates, the less power needed to produce images, which directly impacts image brightness, battery life, and heat generation.
Highly efficient waveguides help produce bright digital content while using less power. This supports longer battery life, reduced heat generation, and more comfortable daily wear.
When efficiency is poor, too much light is lost within the optical system before reaching the eye. This can lead to reduced visibility of virtual content, higher power consumption, and increased thermal output, all of which limit the practicality of AR glasses for everyday use.
