GPS's from Garmin International Inc., Olathe, Kans., are popular items in mapping systems for cars, boats, and aircraft.
GPS's from Garmin International Inc., Olathe, Kans. (garmin.com), are popular items in mapping systems for cars, boats, and aircraft. They are also being added to cell phones, PDAs, and other handheld devices. The miniature LCDs are highly legible in all lighting conditions thanks to Clarex antireflective (AR) acrylic from Astra Products Inc., Baldwin, N.Y. (astraproducts.com). One big challenge during LCD development is to get good image quality. For example, Garmin StreetPilot 2620 plugand-play navigators feature high-resolution color touchscreens. These backlit LCDs must give drivers a bright, colorful, uniform, and highly legible readout even in direct sunlight. Key to meeting this spec is the efficiency with which Clarex AR transmits light and prevents reflection (under 0.5% at 550 nm). The material is a cell-cast polymethyl methacrylate (PMMA) with additional coatings that also resist surface scratches and smudges. Thickness ranges from 0.008 to 0.197-in. in clear or color.