Lamina comprising cube corner elements and retroreflective sheeting

• US 7,156,527 B2
• Filed: 04/01/2003
• Issued: 01/02/2007
• Est. Priority Date: 03/06/2003
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Smith, Kenneth L.
• Primary Examiner(s): Cherry; Euncha P.
• Application Number:
  US10/404,890
• Publication Number:
  US 20040174603A1
• Time in Patent Office: 1,372 Days
• Field of Search: 359/529, 359/530, 359/515, 156/268
• US Class Current: 359/529
• CPC Class Codes: B29C 59/007 Forming single grooves or ribs, e.g. tear lines, weak spots by moulding B29C37/0057; folding lines B29C53/06; in metal articles B21D17/00; by cutting B26D3/08
• CPC Class Codes: B29D 11/00605 Production of reflex reflectors
• CPC Class Codes: B29L 2011/0091 Reflex reflectors
• CPC Class Codes: G02B 1/10 Optical coatings produced by application to, or surface treatment of, optical elements G02B1/08 takes precedence
• CPC Class Codes: G02B 1/18 Coatings for keeping optical surfaces clean, e.g. hydrophobic or photo-catalytic films G02B1/16 takes precedence
• CPC Class Codes: G02B 5/122 cube corner, trihedral or triple reflector type
• CPC Class Codes: G02B 5/124 plural reflecting elements forming part of a unitary plate or sheet
• CPC Class Codes: Y10T 156/1082 Partial cutting bonded sandwich [e.g., grooving or incising]
• CPC Class Codes: Y10T 428/2457 Parallel ribs and/or grooves

Abstract

The present invention is directed to lamina(e) comprising cube corner elements, a tool comprising an assembly of laminae and replicas thereof. The invention further relates to retroreflective sheeting.

Claims

1. A lamina comprising cube corner elements having faces formed from grooves wherein adjacent grooves range from being nominally parallel to nonparallel by less than 1°

, have included angles that differ by at least 2°

, and the included angles of the grooves are arranged in a repeating pattern.

2. The lamina of claim 1 wherein the adjacent grooves are side grooves.

3. The lamina of claim 1 wherein the cube corner elements comprise faces formed from alternating pairs of side grooves.

4. The lamina of claim 1 wherein the cube corner elements consist of faces formed from an alternating pair of side grooves and a primary groove face.

5. The lamina of claim 3 wherein the included angles of each pair of side grooves has a sum of substantially 180°

.

6. The lamina of claim 1 wherein the included angle of a first groove is greater than 90°

by an amount of at least about 5° and

the included angle of a second adjacent groove is less than 90°

by about the same amount.

7. The lamina of claim 6 wherein the included angle of the first groove is greater than 90°

by at an amount ranging from about 10°

to about 20° and

the included angle of the second adjacent groove is less than 90°

by about the same amount.

8. The lamina of claim 1 wherein at least a portion of the elements are canted such that the cube corner elements have an alignment angle between 45°

and 135°

, an alignment angle between 225° and

315°

, and combinations thereof.

9. The lamina of claim 1 wherein the elements each have a face in a common plane that defines a primary groove face.

10. The lamina of claim 1 wherein the elements are preferred geometry cube corner elements.

11. A lamina comprising cube corner elements having faces formed from grooves wherein the faces intersect at a common peak height, adjacent grooves range from being nominally parallel to nonparallel by less than 1°

and the included angles of adjacent grooves differ by at least 2°

.

12. The lamina of claim 11 wherein the adjacent grooves are side grooves.

15. A master tool comprising a plurality of laminae in accordance with claim 11.

16. The master tool of claim 15 wherein the laminae are assembled such that cube corner elements of adjacent laminae are in opposing orientations.

13. A lamina comprising cube corner elements having faces formed from grooves wherein adjacent grooves range from being nominally parallel to nonparallel by less than 1°

, have included angles that differ by at least 2° and

have bisector planes that range from being mutually nominally parallel to nonparallel by less than 1°

.

14. The lamina of claim 13 wherein the adjacent grooves are side grooves.

17. A master tool comprising a plurality of laminae in accordance with claim 13.

18. The master tool of claim 17 wherein the laminae are assembled such that cube corner elements of adjacent laminae are in opposing orientations.

19. A replication of the master tool of claim 17.

20. Retroreflective sheeting comprising a row of preferred geometry cube corner microstructures having faces defined by grooves wherein adjacent grooves in the row range from being nominally parallel to nonparallel by less than 1°

, have included angles that differ by at least 2°

, and the included angles of the side grooves are arranged in a repeating pattern.

21. The retroreflective sheeting of claim 20 wherein the cube corner microstructures comprise cube corner elements.

22. The retroreflective sheeting of claim 20 wherein the elements each have a first face and the first faces define a primary groove face.

23. The retroreflective sheeting of claim 20 comprising a plurality of rows, each row in opposing orientation to an adjacent row.

24. Retroreflective sheeting comprising a row of cube corner elements having faces defined by grooves wherein the faces intersect at a common peak height, adjacent grooves in the row range from being nominally parallel to nonparallel by less than 1°

and the included angles of adjacent side grooves differ by at least 2°

.

25. The retroreflective sheeting of claim 24 wherein the elements each have a first face and the first faces define a primary groove face.

26. The retroreflective sheeting of claim 24 comprising a plurality of rows, each row in opposing orientation to an adjacent row.

27. Retroreflective sheeting comprising a row of cube corner elements having faces defined by grooves wherein adjacent grooves in the row range from being nominally parallel to nonparallel by less than 1°

, have included angles that differ by at least 2° and

have bisector planes that range from being mutually nominally parallel to nonparallel by less than 1°

.

28. The retroreflective sheeting of claim 27 wherein the elements each have a first face and the first faces define a primary groove face.

29. The retroreflective sheeting of claim 27 comprising a plurality of rows, each row in opposing orientation to an adjacent row.