Design, fabrication, and evaluation of Petzval retro-mirror array for floating displays

For the traditional floating displays based on the retro-reflective sheeting, the aberrations and stray light cause the blurred floating image. In order to solve this problem, a specifically designed Petzval retro-mirror array (PRMA) is proposed to achieve the accurate retro-reflected light. The PRMA is composed of the aperture-stop array, Petzval lens array and aspherical mirror. The design and fabrication methods of PRMA are demonstrated in detail. The optical experiment is conducted to evaluate the optical performance of PRMA and obtain the far-field pattern of the retro-reflected light with different incident angles. Based on an angle-limited display source (ALDS), a beam splitter and the designed PRMA, an experimental prototype system is assembled. A clear floating image with a floating distance of 350mm is achieved. With a hand-tracking sensor, the floating image can be rotated, zoomed out or in.