Optical bonding is glued in front of a display to enhance its readability, especially for high-humidity outdoor environments. In such an environment, the most common influenced factor is “fog”, or "condensation", which forms on the inner surface of the display's vandal shield. Another factor is the reflection of sunlight, which causes a mirror-image on the display. Optical bonding is the answer to solve mentioned above. The optical bonding technique fills the air gap with Optical Clear Adhesive (OCA), designed to be very close to that of glass, light reflection at those two interfaces is minimized, to provide the best transmission effect. Optical bonding is implemented by either liquid or sheet form OCA. The attachment process is performed in the air with liquid OCA and either UV or thermal curing process is needed after attachment. On the other hand, vacuum condition is necessary when sheet form OCA is applied.