Retroreflective cube corner sheeting mold and sheeting formed therefrom

Claims

What is claimed is:

1. A lamina suitable for use in a mold for use in forming retroreflective cube corner articles, the lamina having opposing first and second major surfaces defining therebetween a first reference plane, the lamina further including a working surface connecting the first and second major surfaces, the working surface defining a second reference plane substantially parallel to the working surface and perpendicular to the first reference plane and a third reference plane perpendicular to the first reference plane and the second reference plane, comprising:

a first groove set including one V-shaped groove in the working surface of the lamina, the groove defining a first groove surface and a second groove surface that intersect to define a first groove vertex;

a second groove set including one V-shaped groove in the working surface of the lamina, the groove defining a third groove surface and a fourth groove surface that intersect to define a second groove vertex, the third groove surface intersecting the first groove surface substantially orthogonally to define a first reference edge; and

a third groove set including three parallel V-shaped grooves in the working surface of the lamina, each such groove defining a fifth groove surface and a sixth groove surface that intersect to define a third groove vertex, the fifth groove surface of one of the three parallel grooves intersecting substantially orthogonally with the first and third groove surfaces to form a first cube corner disposed in a first orientation.

2. The lamina of claim 1 wherein the fourth groove surface intersects the second groove surface substantially orthogonally to define a second reference edge.

3. The lamina of claim 2 wherein the sixth groove surface of another of the three parallel grooves intersects substantially orthogonally with the second and fourth groove surfaces to form a second cube element corner disposed in a second orientation different from the first orientation.

4. The lamina of claim 1 wherein the first groove vertex and the second groove vertex are disposed in a plane that intersects the first reference plane at an orthogonal angle and that intersects the second reference plane at an orthogonal angle.

5. The lamina of claim 1 wherein the first groove vertex and the second groove vertex are disposed in a plane that intersects the first reference plane at an oblique angle and that intersects the second reference plane at an orthogonal angle.

6. The lamina of claim 1 wherein the first groove vertex extends along an axis that intersects the first major surface of the lamina and the second reference plane.

7. The lamina of claim 1 wherein the second groove vertex extends along an axis that intersects the second major surface of the lamina and the second reference plane.

8. The lamina of claim 1 wherein the first groove vertex and the second groove vertex are disposed in planes that intersect the third reference plane at an orthogonal angle and that intersect the second reference plane at angles that measure between about 45.degree. and about 90.degree..

9. The lamina of claim 1 wherein the first groove vertex and the second groove vertex are disposed in planes that intersect the third reference plane at an orthogonal angle and that intersect the second reference plane at angles that measure between about 45.degree. and about 60.degree..

10. The lamina of claim 1 wherein the first groove set and the second groove set comprise a plurality of grooves, each groove having an included angle that measures between about 10.degree. and about 170.degree..

11. The lamina of claim 1 wherein the third groove vertex extends along an axis that intersects the first major surface of the lamina and the second major surface of the lamina and is substantially perpendicular to the first reference plane.

12. The lamina of claim 1 wherein the first reference edge extends along an axis that intersects the second reference plane at an acute angle .gamma..sub.1 and the fifth groove surface is disposed in a plane that intersects the third reference plane at an acute angle .alpha..sub.1 =.gamma..sub.1.

13. The lamina of claim 2 wherein the second reference edge extends along an axis that intersects the second reference plane at an acute angle .gamma..sub.2 and the sixth groove surface is disposed in a plane that intersects the third reference plane at an acute angle .alpha..sub.2 =.gamma..sub.2.

14. The lamina of claim 1 wherein the first, second, and third groove sets form a plurality of discrete cube corner elements, each of the discrete cube corner elements being located on the lamina.

15. The lamina of claim 1 wherein adjacent first and second major surfaces comprise a substantially planar interface.

16. A mold suitable for use in forming retroreflective sheeting comprising a plurality of laminae, including the lamina of claim 1.

17. A method of manufacturing a lamina for use in a mold suitable for use in forming retroreflective cube corner articles, the lamina having opposing first and second major surfaces defining therebetween a first reference plane, the lamina further including a working surface connecting the first and second major surfaces, the working surface defining a second reference plane substantially parallel to the working surface and perpendicular to the first reference plane and a third reference