LAMINA COMPRISING CUBE CORNER ELEMENTS AND RETROREFLECTIVE SHEETING

• US 20070014012A1
• Filed: 09/25/2006
• Published: 01/18/2007
• 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
• Granted Patent: US 7,422,334 B2
• Time in Patent Office: Days
• US Class Current: 359/530
• 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 preferred geometry cube corner elements wherein at least a portion of the cube corner elements are canted having an alignment angle selected from alignment angles between 45°

and 135°

, alignment angles between 225° and

315°

, and combinations thereof.

2. A master tool comprising a plurality of laminae in accordance with claim 1.

3. The master tool of claim 2 wherein the elements have a shape in plan view selected from trapezoids, rectangles, parallelograms, pentagons, and hexagons.

4. The master tool of claim 2 wherein the laminae are assembled such that cube corner elements of adjacent laminae are in opposing orientations.

5. A replication of the master tool of claim 2.

6. A master tool comprising a plurality of laminae in accordance with claim 1.

7. The master tool of claim 6 wherein the laminae are assembled such that cube corner elements of adjacent laminae are in opposing orientations.

8. A replication of the master tool of claim 6.

9. Retroreflective sheeting comprising a row of preferred geometry cube corner microstructures wherein a first cube corner element is canted having an alignment angle between 45°

and 135° and

a second adjacent cube is canted having an alignment angles between 225° and

315°

.

10. The retroreflective sheeting of claim 9 wherein the cube corner microstructures comprise cube corner elements.

11. The retroreflective sheeting of claim 9 wherein the first cube corner element is canted having an alignment angle between 60°

and 120° and

a second adjacent cube is canted having an alignment angles between 240° and

300°

.

12. The retroreflective sheeting of claim 9 wherein the alignment angle of the first cube differs from 0°

by substantially the same amount as the alignment angle of the second cube differs from 0°

.

13. The retroreflective sheeting of claim 9 wherein the alignment angle of the first cube differs from 180°

by substantially the same amount as the alignment angle of the second cube differs from 180°

.

14. The retroreflective sheeting of claim 9 wherein the elements each have a first face and the first faces define a primary groove face.

15. Retroreflective sheeting comprising an array of preferred geometry cube corner elements that exhibit a uniformity index of at least 1 at an entrance angle of at least 30°

.

16. The retroreflective sheeting of claim 15 wherein the uniformity index is for an entrance angle of 40°

.

17. The retroreflective sheeting of claim 15 wherein the array is substantially free of tiling in more than one orientation.

18. The retroreflective sheeting of claim 15 wherein the uniformity index is at least 3.

19. The retroreflective sheeting of claim 15 wherein the uniformity index is at least 5.

20. The retroreflective sheeting of claim 15 wherein the cubes are canted having an alignment angle selected from alignment angles between 45°

and 135°

, alignment angles between 225° and

315°

, and combinations thereof.

21. The retroreflective sheeting of claim 15 wherein the cubes are canted having an alignment angle selected from alignment angles between 60°

and 120°

, alignment angles between 240° and

300°

, and combinations thereof.

22. Retroreflective sheeting comprising a pair of adjacent rows of preferred geometry cube corner elements wherein adjacent elements in a row have at least one dihedral edge that ranges from being nominally parallel to nonparallel by less than 1°

and wherein the pair of rows comprise at least two types of matched pairs.