Retroreflective sheeting including cube corner elements

• US 10,495,792 B2
• Filed: 10/12/2018
• Issued: 12/03/2019
• 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:
  US16/159,401
• Publication Number:
  US 20190049635A1
• Time in Patent Office: 417 Days
• Field of Search: 359530
• 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;

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;

wherein at least one of the cube corner elements 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;

wherein the cube corner elements comprise preferred geometry cube corner elements,

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°

.

2. The retroreflective sheeting of claim 1, wherein two of the three dihedral angle errors on a cube corner element are different from each other.

3. The retroreflective sheeting of claim 2, wherein two of the three dihedral angle errors on a cube corner element are different in magnitude from each other.

4. The retroreflective sheeting of claim 2, wherein the dihedral angle errors are varied in a repeating pattern.

5. The retroreflective sheeting of claim 1, wherein three of the three dihedral angle errors on a cube corner element are different from each other.

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

7. The retroreflective sheeting of claim 5, wherein the dihedral angle errors are varied in a repeating pattern.

8. 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°

.

9. 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.

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

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

12. The retroreflective sheeting of claim 1, wherein the sheeting is white.

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

14. Retroreflective sheeting, comprising:

a plurality of cube corner elements;

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;

wherein at least one of the cube corner elements 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;

wherein the cube corner elements comprise preferred geometry cube corner elements,

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°

.

15. The retroreflective sheeting of claim 14, wherein the sheeting is white.