Retroreflective sheeting including cube corner elements

• US 10,101,509 B2
• Filed: 09/23/2016
• Issued: 10/16/2018
• 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:
  US15/274,646
• Publication Number:
  US 20170010395A1
• Time in Patent Office: 753 Days
• Field of Search: 359530, 359531
• 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 disclosure is directed to lamina(e) comprising cube corner elements, a tool comprising an assembly of laminae and replicas thereof. The disclosure further relates to retroreflective sheeting.

Claims

1. Retroreflective sheeting, comprising:

a plurality of cube corner elements comprising full cubes;

wherein at least one cube comprises a 1-2 dihedral angle error and a 1-3 dihedral angle error that are varied in a repeating pattern;

wherein at least one of the cube corner elements has three square faces and forms a hexagonal shape when viewed in plan view; and

wherein at least one of the cube corner elements forms a pentagonal shape when viewed in plan view.

2. The retroreflective sheeting of claim 1, wherein at least one of the cube corner elements has at least one dihedral angle error having a magnitude between 1 arc minute and 60 arc minutes.

3. The retro reflective sheeting of claim 1, wherein at least one of the cube corner elements has three dihedral angle errors having a magnitude between 1 arc minute and 60 arc minutes.

4. The retroreflective sheeting of claim 3, wherein two of the three dihedral angle errors on a cube corner element are different from each other.

5. The retroreflective sheeting of claim 3, wherein two of the three dihedral angle errors on a cube corner element are different in magnitude from each other.

6. The retroreflective sheeting of claim 3, wherein three of the three dihedral angle errors on a cube corner element are different from each other.

7. The retroreflective sheeting of claim 6, wherein three of the three dihedral angle errors on a cube corner element are different in magnitude from each other.

8. The retroreflective sheeting of claim 1, wherein the dihedral angle errors are varied in a repeating pattern.

9. The retroreflective sheeting of claim 1, wherein more than two of the cube corner elements are in a row wherein at least one dihedral edge of the cube corner elements range from being nominally parallel to nonparallel by less than 1°

.

10. The retroreflective sheeting of claim 1, wherein at least one cube corner element has a first face and the first faces define a primary groove face.

11. The retroreflective sheeting of claim 1, wherein the cube corner elements comprise preferred geometry cube corner elements.

12. The retroreflective sheeting of claim 1, wherein the retroreflective sheeting comprises cube corner cavities.

13. The retroreflective sheeting of claim 1, wherein the cube corner elements have an average height less than 0.1 mm and a lateral dimension less than 1 mm.

14. The retroreflective sheeting of claim 1, wherein the sheeting exhibits an average brightness at 0°

and 90°

orientation of at least 375 candelas/lux/m² for an entrance angle of −

4° and

an observation angle of 0.5°

.

15. The retroreflective sheeting of claim 14, wherein the average brightness at 0°

and 90°

is at least 625 candelas/lux/m² for an entrance angle of −

4° and

an observation angle of 0.2°

.

16. The retroreflective sheeting of claim 14, wherein the average brightness at 0°

and 90°

is at least 575 candelas/lux/m² for an entrance angle of −

4° and

an observation angle of 0.33°

.

17. The retroreflective sheeting of claim 14, wherein the average brightness at 0°

and 90°

is at least 80 candelas/lux/m² for an entrance angle of −

4° and

an observation angle of 1.0°

.

18. The retroreflective sheeting of claim 1 wherein the sheeting further comprises a seal film.

19. The retroreflective sheeting of claim 1, wherein the sheeting further comprises a specular reflective coating.