Optical bonding is the process of filling the air gap between the front surface and an LCD with an optically clear index matched material. This has significant benefits.
Benefits of optical bonding
1. Increased contrast and readability (outdoor has largest advantage)
The main advantage of optical bonding is the improved readability and contrast of the display, even under intense lighting conditions and wide viewing angles. This is accomplished by eliminating changes in index of refraction between the LCD, the front surface and air gap. The yellow arrows represent negative reflections that shrink your pulis and reduce perceived brightness and reduce actual contrast.
2. Protection against foreign objects and condensation
Since there is no gap between the LCD and front surface no foreign particles or condensation can occur in that gap. This is critical in outdoor environments where temperature can vary greatly causing condensation.
3. Increased Vandal Resistance
Most optical bonding adhesives are shock absorbing materials. Having a shock absorbing material between the LCD and front surface instead of air helps the front glass handle shock without breaking.