Lamina comprising cube corner elements and retroreflective sheeting

• US 7,329,012 B2
• Filed: 08/02/2007
• Issued: 02/12/2008
• Est. Priority Date: 03/06/2003
• Status: Expired due to Term

• 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:
  US11/832,908
• Publication Number:
  US 20070268582A1
• Time in Patent Office: 194 Days
• Field of Search: 359529-533
• 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. Retroreflective sheeting comprising an array of preferred geometry cube corner elements that exhibits an average brightness at 0°

and 90°

orientation according to ASTM D4596-1a 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 the average brightness is at least 400 candelas/lux/m².

3. The retroreflective sheeting of claim 1 wherein the average brightness is at least 450 candelas/lux/m².

4. The retroreflective sheeting of claim 1 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°

.

5. The retroreflective sheeting of claim 1 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°

.

6. The retroreflective sheeting of claim 1 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°

.

7. The retroreflective sheeting of claim 1 wherein the average brightness at 0°

and 90°

is at least 20 candelas/lux/m² for an entrance angle of −

4° and

an observation angle of 1.5°

.

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

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