US Patent 10198978 Viewing optics test subsystem for head mounted displays

An optical evaluation workstation evaluates quality metrics (e.g., optical contrast) of optical elements of a HMD. The workstation includes a test pattern, an optical element feed assembly, a light source, a camera and a control module. The light source backlights the test pattern with diffuse light. The optical element feed assembly receives an optical element of a HMD and places the optical element at a first distance from the test pattern corresponding to a distance between the optics block in the HMD and an exit pupil of the HMD. The camera images the test pattern through the optical element and the camera is positioned at a second distance from the test pattern corresponding to a distance between the exit pupil and an electronic display in the HMD. The control module generates a test report for presentation to a user based on the evaluation of the optical element.