FIELD: physics.
SUBSTANCE: retroreflective sheet comprises a flat transparent sheet with a substrate and an array of metal coated angle reflectors. The angle reflectors have angle of inclination equal to 10n-9°±1.5° where n is refraction index of the material of the sheet. The smallest of the three angles between edges of dihedral angles and the front surface of the sheet is at least 19.472° less than the smallest of the three angles between edges of the angle reflectors and the front surface of the sheet. Thickness of the substrate is selected such that it ranges from 0.75H to approximately 4.5H, where H is height of the angle reflectors. The angle reflectors are formed by three sets of parallel V-shaped grooves. The obtained sheet has coefficient of brightness, measured using a colorimetre with geoemetry 0/45 when the material is illuminated with a beam of light with deviation from normal incidence within limits of 5° and with reception of the reflected light in an annular segment corresponding to angles of reflection ranging from 40° to 50°, which is greater than 0.20.
EFFECT: high coefficient of brightness during daylight illumination.
20 cl, 8 dwg
