Engineering of head-mounted projective displays

Abstract

Head-mounted projective displays (HMPD's) are a novel type of head-mounted display. A HMPD consists of a miniature projection lens mounted upon the user's head and retroreflective sheeting material placed strategically in the environment. First, the imaging concept of a HMPD is reviewed and its potential advantages and disadvantages are discussed. The design and a bench prototype implementation are then presented. Finally, the effects of retroreflective materials on the imaging properties and the optical properties of HMPD's are comprehensively investigated.

Diffraction of phase conjugate material in a new HMD architecture

“…The amount of light in the observation plane depends on the microstructure and the retro-reflective properties of the materials employed. 8 We can define the amount of light retro-reflected from the phase conjugate material to the user's eye by basing the analysis on the diffraction efficiency of the microstructure geometry. This approach yields accurate results, providing that first the microstructure is large compared to the wavelength, and the diffracted field is observed far from the phase conjugate material; based on these conditions we can treat the diffraction of light as a scalar phenomenon.…”

Trends in augmented reality tracking, interaction and display: A review of ten years of ISMAR

“…However, light from the HMPD needs to pass through the display optics several times which can cause a reduction in image brightness. Outside of IS-MAR, the idea of HMPDs was first presented by [25]; other related work can be referred to in [37].…”

Dual-purpose lens for an eye-tracked projection head-mounted display

“…Based on our experience with designing and building HMPDs [12][13][14] , the challenge was related to integrating the eyetracking system without compromising the compactness of the HMPD and without obstructing the users view.…”