Design and fabrication of an off-axis four-mirror system for head-up displays

Abstract

Head-up displays (HUDs), as one kind of the augmented reality (AR) applications, enable users to enhance the situational awareness. In this paper, we propose a design of a HUD employing the freeform off-axis four-mirror construction, in which the eyebox and eye relief as large as 120 m m × 80 m m and 400 mm, respectively, are derived. In the part of system design, the biocular parallax is evaluated and corrected. An optimization strategy in forward ray-tracing mode is presented to directly govern the biocular parallax, and the convergence, divergence, and dipvergence are finally constrained within 3.5 mrad, 1.5 mrad, and 2.0 mrad, respectively. An overall design procedure of a HUD, including initial configuration, structure constraints, optimization method, and parallax correction, is illustrated in detail. After analyzing the tolerance, a proof-of-concept prototype with the field of 24 ∘ × 15 ∘ is developed to demonstrate the image quality.

Notice of Violation of IEEE Publication Principles: Design and Performance of an Off-Axis Free-Form Mirror for a Rear Mounted Augmented-Reality Head-Up Display System

“…The volume is small, and the imaging quality meets the requirements of use. In order to realize the control display of the parallax, Luo Gu et al [26] proposed an optimization strategy for the forward ray tracing mode that directly controls the binocular parallax. The eye box size of the proposed system is 120 mm * 80 mm 2 , and the parallax of the eyes is evaluated and corrected.…”

AR-HUD Optical System Design and Its Multiple Configurations Analysis

“…According to the type of imaging, current AR-HUD optical systems can be divided into two categories: geometric optical imaging and physical optical imaging. Geometric optical imaging include the author-designed off-axis three-mirror HUD optical system, where the PGU, plane mirror, and freeform reflector were laid out in the same horizontal plane [10][11][12]. By using Solidworks' basic mechanical assembly structure to determine the coordinates of the plane mirror and PGU, the light constraint equations were developed to guarantee unhindered light transmission [11].…”

Design and exploration of freeform three-mirror imaging systems with integrated primary and tertiary mirrors using same expression

“…The decenter and tilt of mirrors will induce unconventional aberrations with special field dependence 4 , which will be well matched by the aberration that the freeform surfaces induced 5,6 . Therefore, the freeform surfaces have been successfully used in many domains [7][8][9][10][11][12][13] .…”