Dontech IMO-bond™ Optical Bonding & VARGard™ Film Laminations

Electronic displays are commonly used in outdoor applications such as digital signage, kiosks, GPS systems, and instrumentation for military, medical and industrial use.

Operating electronic displays in these high ambient light conditions poses engineering challenges including:

  • Contrast
  • Color Saturation
  • Thermal Loading
  • Temperature Extremes
  • EMI/RFI Shielding
  • Ruggedization of the Optics (e.g., to withstand shock, vibration and impact)

To minimize the impact of reflected ambient light, it is necessary to:Dontech’s IMO-bond™ (Index Matched Optical) process is designed to perform in a high ambient light environment, which occurs when the amount of light reflected by a display is close to or exceeds the amount of light emitted by the display. Direct sunlight can have illumination of greater than 100,000 lux. When this ambient light is reflected off of a display’s untreated glass or plastic surfaces, the contrast loss can be close to 100% and will cause “wash-out” as the display’s luminance is exceeded. In addition, high ambient light can cause thermal loading of the display system. In particular, LCDs are affected when the “clearing temperature” of the liquid crystals is exceeded, causing the display’s contrast to degrade.

  • Apply broadband antireflective coating to reduce surface reflections (e.g., less than 0.75%, 0.50% or 0.25% photopic reflection).
  • Optically couple an optical filter or touch screen to the front of the display to eliminate internal reflections.

Dontech’s solutions for improving electronic display performance in high ambient light conditions include:

  • VARGard™ – antireflective and antiglare film laminations
  • IMO-bond™ Index Matched Optical (IMO) bonding of optical filters and touch screens
  • Passive Enhancements – addition of optical compensation films and reflectors
  • Active Enhancements – addition of custom CCFL and LED lighting solutions
  • Display Enhancement Components – AR, AR/AG cover glass, enhanced touch screens, polarizers, colored contrast filters

High reflections at untreated surface interface cause “display wash-out”

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Surface reflections reduced via optical bonding

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