Hurlbut, J., Cashen, D., Robb, E., Spangler, L. et al., "Next Generation PVB Interlayer for Improved HUD Image Clarity," SAE Int. J. Passeng. Cars - Mech. Syst. 9(1):360-365, 2016, doi:10.4271/2016-01-1402.
Head-up display (HUD) technology creates inherent driver safety advantages by displaying critical information directly in the driver’s line of sight, reducing eyes off road and accommodation time. This is accomplished using a system of relay optics and windshield reflection to generate a virtual image that appears to hover over the hood near the bumper. The windshield is an integral optical component of the HUD system, but unfortunately the windshield-air interface causes a double image ghost effect as a result of refractive index change, reducing HUD image clarity. Current technology uses a constant angle wedged PVB windshield interlayer to eliminate double image at a single driver height. However, the HUD double image persists for all other viewing locations. Eastman Chemical Company has developed a new interlayer technology which eliminates the double image at all driver locations by tuning the wedge angle as a function of driver occupant seated height. The purpose of this paper is to discuss this exciting technology and its application to produce best in class HUD image clarity.