Waveguides in Magic Leap and HoloLens
A recent article by Karl Guttag discusses waveguides, which are optical devices involved in the components in devices such as the Microsoft HoloLens. Light enters the thin piece of glass, projecting a small image on one side of it; using total internal reflection inside the piece of glass, the image exits in a different place.
The article discusses a major disadvantage of waveguides; the light that enters the glass has to be at 45 degrees, then at 45 degrees again when it leaves. This means that the image is often of a worse quality, as not all of the light makes the correct turns. ‘Waveguide glow’, as Karl Guttag calls it, is another issue that can occur, which causes a glow around high contrast objects or text.
The conclusions made by the article are:
- The waveguide did not significantly decrease the size of the HoloLens
- Waveguides worsen the image quality compared to simpler combiner designs
- HoloLens’ use of waveguide restricted them to only using certain display devices that are compatible; they are unable to use OLED or tech which emits a broader spectrum of light
- Even if the device was smaller, getting more SDKs in developers is important sooner rather than later
Readers can read the full article here.