A small degree of wedge angle has been found useful in minimizing ghosting in automotive windshields with Heads Up Displays (HUD).   The Lumetrics OptiGauge II can measure the thickness of all layers of a laminated windshield simultaneously and is capable of determining the wedge angle as a function of location on the windshield with a high degree of accuracy as well as determining how much wedge is in each layer.

 

Windshield Wedge Angle and Layer Thickness Measurements