Transmittance of the surface of a material is its effectiveness in transmitting radiant energy. It is the fraction of incident electromagnetic power that is transmitted through a sample, in contrast to the transmission coefficient, which is the ratio of the transmitted to incident electric field.Internal transmittance refers to energy loss by absorption, whereas (total) transmittance is that due to absorption, scattering, reflection, etc. Polycarbonate a colorless transparent amorphous thermoplastic material, good light transmission can be used as reflective tape surface material. Used in the field of reflective reverse reflection. Polycarbonate with its unique high transmittance, High refractive index, high impact resistance, Dimensional stability and easy molding and other characteristics, in this area occupies an extremely important position. Optically Clear Adhesives (OCA) are highly specialized optically clear free-film adhesives offering superior clarity and excellent adhesion to various types of transparent substrates. OCAs are easy to convert and are contaminant-free, resulting in improved bubble resistance in laminations exposed to high temperature and high humidity. Common applications include displays, touch panels and others requiring an optically clear bond.