Measuring Windshields with Heads up Displays

Lumetrics handheld probe holder with 50mm Probe

Since the formation of the National Highway Traffic Safety Administration in 1970, the NHTSA has implemented regulations impacting all areas of vehicle safety including automotive glass.  The OptiGauge helps with the process by obtaining highly accurate glass thickness measurements to ensure glass is to manufacturer's specifications.

For years windshields have been comprised of two pieces of glass approximately 2mm thick with an approximately 1mm layer of vinyl sandwiched in-between.  Today, many windshields include another thin, sound absorbing vinyl layer that helps reduce road noise.

Now technology and driver safety intersect on the windshield.  Heads Up Display (HUD) windshields provide drivers with access to important dashboard information such as speed and navigation while providing the safety benefit of maintaining eyes on the road and reducing driver distractions.

In order to maximize optical quality, HUD windshield technology requires further advancements in windshield manufacturing.  The most notable requirement is the ability to insert a wedge shaped polymer (Polyvinyl butyral - PVB) between the glass sheets. This wedge shape eliminates the “ghost” reflections that normal windshields produce when using HUD.  The problem then becomes how to measure the wedge or thickness of the laminate from top to bottom.  The generally accepted practice of using a micrometer to measure the laminate thickness at the top and bottom of the windshield now becomes obsolete as manufacturers need to measure thickness across the whole windshield from top to bottom in a non-destructive manner.  

Lumetrics invented the OptiGauge® which provides highly accurate and reliable glass thickness measurements with our custom solutions to meet the many needs of windshield glass manufacturers.  First we have provided multiple systems to the largest PVB manufacturers in the world to measure the wedge angle in the PVB as it is being produced.  Additionally, we have sold more systems to the auto glass manufacturers, who make the windshields.   The OptiGauge assists these customers with product development, optical quality, and troubleshooting lamination problems.

The Lumetrics OptiGauge is based on the theory of time domain interferometry to produce highly accurate (.01micron accuracy) measurements.  For more information or a demonstration please contact Lumetrics - www.lumetrics.com, 585-214-2455.