White PaperAutomotive

Testing Windshield Glass to Ensure High-Quality Head-up Displays


Automotive head-up displays (HUD) project virtual images onto the windshield that are visualized through the glass at a perceived distance of several meters. This enables drivers to view speed, navigation, and other information directly within their line of sight while driving, reducing the need to take their eyes off the road.

Because the windshield acts as an optical component of the HUD system, the visual performance of HUDs can be dramatically impacted by the glass through which information is viewed. Variations in windshield glass form, lamination, layer thickness, and wedge angle may result in visible defects that appear as distortion or ghosting (duplication) of HUD virtual images when viewed through the glass.

Requirements for HUD testing are based on industry-standard test parameters and formulas in addition to OEM specifications. These requirements must be met by suppliers throughout the HUD ecosystem, from glass makers to projection system manufacturers. For glass inspection, tens of calculations must be performed by an image-based inspection system to characterize each visual defect — not just once, but at several points defined within the HUD viewing area, or eyebox.

In this case study, CP Industries shares their decades-long experience engineering and delivering fully integrated test fixtures for applications like HUD glass inspection to the automotive industry. With the breadth and complexity of HUD visual test specifications increasing, the CP team recounts the benefits of transitioning their integrated inspection cameras and software from rudimentary machine vision systems to a complete HUD measurement solution from Radiant Vision Systems—combining imaging photometers, electronic autofocus lenses, and specially developed HUD test software.

With a fully featured HUD measurement solution on board, CP Industries' new HUDSON test system offers performance and delivery-time improvements that help their important automotive customers meet critical objectives in manufacturing.

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