Retro reflective sheeting types of apples

There are nine types and five classes of retroreflective sheeting. Types are determined by conformance to the retrore- flectance, color, and durability requirements listed in section 6.1 of ASTM 4956-01 and may be of any construction providing that those requirements are met. The retro-reflective sheeting typically comprises an optically clear layer with one smooth surface, and the opposite prismatic surface. More than 5000 micro-prisms are densely positioned within one squared centimeter. As shown in Fig.1a, the micro-prism is a tetrahedron consisting of three mutually perpendicular faces. A set of three mutually perpendicular reflective surfaces, placed to form the internal corner of a cube, work as a retroreflector. The three corresponding normal vectors of the corner's sides form a basis (x, y, z) in which to represent the direction of an arbitrary incoming ray, [a, b, c]. The three types of reflection (mirror reflection, diffuse reflection and retroreflection) are illustrated in Figure 1. Retroreflection, as can be seen in the bottom illustration, is the phenomenon of light rays striking a surface and being redirected back to the source of light. Retroreflective Sheeting Transcript. Reflective sheeting is the material that makes road signs visible in the dark without having to rely on electricity. Visibility increases with increasing grades of reflective sheeting with Diamond grade providing the most visibility for signs. 9 Types of Sheeting