Eyebox centering using chromatic aberrations of virtual reality head-mounted displays
Ryan Beams, Andrea S. Kim, Aldo G. Badano · 2020
We demonstrate that transverse chromatic aberration (TCA) measurements can be used to determine the eyebox of a virtual reality head-mounted display using a digital test pattern, which consists of red, green, and blue bars placed horizontally and vertically at ±5°, ±10°, ±15° in the field of view. The pattern also features a white cross in the center of the field of view to determine the horizontal and vertical resolution. This provides simultaneous measurements of the TCAs and resolution for a given position of the camera in the eyebox. A map of the eyebox was generated by raster-scanning the position of the camera over the eyebox. The results for the Oculus Rift show that resolution has approximately a quadratic dependence on the position in the eyebox whereas the response to TCAs is linear. Therefore, TCA provides a more sensitive eyebox measurement at small displacements allowing for repeatable centering within 0.5 mm.