Enclosed lens type retroreflective sheet with wide-angle reflective performance and external illumination system

摘要

The retroreflective sheet of the present invention comprises a surface layer (1) including at least one layer, a focusing layer (2) containing glass spheres (3), and a metal reflective layer (4) on the back side of the focusing layer (2), wherein the glass spheres (3) are disposed at random locations in the thickness direction of the focusing layer (2). The external illumination system of the present invention comprises a sign having a sign face including the above-mentioned retroreflective sheet, and an external illumination source, and the distance from the illumination source to the sign face is within a range of at least 1 m and no more than 100 m. The present invention thereby provides a retroreflective sheet and an external illumination system with which wide-angle reflective performance with a wider incidence angle and observation angle can be ensured.