US 4,938,563 A · High efficiency cube corner retroflective material

Abstract

The present invention provides a retroreflective material which is efficient at high angles of incidence and which may be individually tailored so as to distribute light retroreflected by the material into a desired pattern or divergence profile. The retroreflective material of the present invention comprises a transparent surface layer having a front side and a back side and an array of cube corner reflective elements, each of the reflecting elements including a rectangular base on the back side of the surface layer, two rectangular faces nearly perpendicular to each other each one being joined to an edge of the rectangular base to form a reflecting element having a triangular cross section, and two triangular faces that are approximately parallel to each other and approximately perpendicular to the rectangular faces, and forming the ends of the reflecting elements; and the triangular and rectangular faces defining a pair of approximate cube corners therebetween, the reflecting elements arranged with their bases adjacent to the surface layer. The terms "approximately parallel" and "approximately perpendicular" are used herein to refer to faces which are truly parallel or perpendicular and faces which have small variations from true parallelism or perpendicularity.

Claims23

Dependent claims

A retroreflective material comprising a transparent surface layer having a front side and a back side and an array of cube corner reflective elements, each of said reflecting elements including:

(a) a rectangular base on the back side of the surface layer,
(b) two rectangular faces approximately perpendicular to each other, each one being joined to an edge of the rectangular base to form a reflecting element having a triangular cross section;
and
(c) two triangular faces that are approximately parallel to each other and approximately perpendicular to said rectangular faces, and
forming the ends of the reflecting elements;
said triangular and said rectangular faces defining a pair of cube corners therebetween;
said reflecting elements being formed by two approximately perpendicular sets of parallel grooves, a first set of V-shaped grooves, and a second-set of grooves having a pair of faces nearly perpendicular to said rectangular base, at least one of the sets of grooves including more than one groove having a groove side angle that differs from another groove side angle of the same set by a small amount less than 3.degree., whereby the array of cube corner retroreflective elements is characterized by small variations in at least one of the dihedral angles between the faces from one reflecting element to another, said variations existing in at least some but not necessarily all of the reflecting elements.

4 more elements

A retroreflective material comprising a transparent surface layer having a front side and a back side and an array of cube corner reflecting elements, each of said reflecting elements including:

(a) a rectangular base on the back side of the surface layer;
(b) two approximately mutually perpendicular rectangular faces, each being joined to an edge of the rectangular base to form a reflecting element having a triangular cross section, and
(c) two triangular faces that are approximately parallel to each other and approximately perpendicular to said rectangular faces;
said triangular and rectangular faces defining a pair of cube corners therebetween;
said reflecting elements being formed by two perpendicular sets of parallel grooves, a first set of V-shaped grooves, and a second set of grooves having a pair of faces nearly perpendicular to said rectangular base, at least one of the sets of grooves including more than one groove having a groove side angle that differs from another groove side angle of the same set by a small amount less than 3.degree., whereby the array of cube corner retroreflective elements is characterized by small variations in at least one of the dihedral angles between the faces from one reflecting element to another, said variation existing in at least some but not necessarily all of the reflecting elements;
each pair of said rectangular faces defining an angle of intersection having a bisector which intersects said base, said bisector forming an angle Beta with a line perpendicular to said base, said reflective material including perpendicular bisector elements wherein Beta is substantially zero and canted bisector elements wherein Beta is about 0.degree. to less than 45.degree..

3 more elements

Dependencies are inferred from the claim text.

High efficiency cube corner retroflective material

Life of this patent

High efficiency cube corner retroflective material

Life of this patent

Abstract

Claims23