Retroreflective sheeting including cube corner elements

• US 8,251,525 B2
• Filed: 08/12/2011
• Issued: 08/28/2012
• 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:
  US13/208,988
• Publication Number:
  US 20110317265A1
• Time in Patent Office: 382 Days
• Field of Search: 359/529, 359/530, 428/167, 264/1.1, 264/1.6, 264/1.9
• 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 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 grooves that include

a first groove having a first groove surface and a second groove surface, the first groove surface and the second groove surfaces of the first groove intersecting at a first groove vertex;

a second groove having a first groove surface and a second groove surface, the first groove surface and the second groove surfaces of the second groove intersecting at a second groove vertex;

a plurality of cube corner elements each of which has a first groove surface that is a part of the first groove, a second groove surface that is a part of the second groove, and a primary groove face;

wherein the first groove and the second groove are parallel to each other within the degree of precision of the manufacturing process;

wherein the first groove is nonparallel to a reference plane by amounts ranging from less than about 1 degree to greater than the degree of precision of the manufacturing process;

wherein the reference plane corresponds to the y-z plane in a Cartesian coordinate system where the x-y plane extends substantially coplanar with the sheeting along which the cube corner elements are located and the x-z plane contains the primary groove vertex; and

wherein the second groove is nonparallel to the reference plane by between about the degree of precision of the manufacturing process and one degree.

2. The retroreflective sheeting of claim 1, wherein the cube corner elements are preferred geometry cube corner elements.

3. The retroreflective sheeting of claim 1, wherein the first and second grooves have different skew.

4. The retroreflective sheeting of claim 1, wherein the first groove has positive skew and the second groove has negative skew.

5. The retroreflective sheeting of claim 1, wherein the skew of the first groove varies in magnitude from the skew of the second groove.

6. The retroreflective sheeting of claim 1, wherein the first and second grooves have different inclination.

7. The retroreflective sheeting of claim 1, wherein the first groove has a positive inclination and the second groove has negative inclination.

8. The retroreflective sheeting of claim 1, wherein the inclination of the first groove varies in magnitude from the inclination of the second groove.

9. The retroreflective sheeting of claim 1, wherein the first and second grooves have skew and inclination.

10. The retroreflective sheeting of claim 1, wherein the cube corner elements have a lateral dimension of less than about 0.020 inches.

11. The retroreflective sheeting of claim 1, wherein the cube corner elements have a lateral dimension of less than about 0.010 inches.

12. The retroreflective sheeting of claim 1, wherein the two grooves are within a single side groove set.

13. The retroreflective sheeting of claim 1, wherein the degree of precision of the manufacturing process is ¼

arc minute.

14. The retroreflective sheeting of claim 1, wherein the degree of precision of the manufacturing process is 2/8 arc minute.

15. The retroreflective sheeting of claim 1, wherein the degree of precision of the manufacturing process is 3/16 arc minute.

16. The retroreflective sheeting of claim 1, wherein the degree of precision of the manufacturing process is ½

arc minute.

17. Retroreflective sheeting, comprising

a plurality of grooves that include

a first groove having a first groove surface and a second groove surface, the first groove surface and the second groove surfaces of the first groove intersecting at a first groove vertex;

a second groove having a first groove surface and a second groove surface, the first groove surface and the second groove surfaces of the second groove intersecting at a second groove vertex;

a plurality of cube corner elements each of which has a first groove surface that is a part of the first groove, a second groove surface that is a part of the second groove, and a primary groove face;

wherein the first groove vertex and the second groove vertex are parallel to each other within the degree of precision of the manufacturing process;

wherein the first groove is nonparallel to a reference plane by amounts ranging from less than about 1 degree to greater than the degree of precision of the manufacturing process;

wherein the reference plane corresponds to the y-z plane in a Cartesian coordinate system where the x-y plane extends substantially coplanar with the sheeting along which the cube corner elements are located and the x-z plane contains the primary groove vertex;

wherein the second groove is nonparallel to the reference plane by between about the degree of precision of the manufacturing process and one degree.