Lamina comprising cube corner elements and retroreflective sheeting

• US 8,016,435 B2
• Filed: 04/12/2010
• Issued: 09/13/2011
• 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:
  US12/758,695
• Publication Number:
  US 20100232019A1
• Time in Patent Office: 519 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 an array of cube corner elements that exhibits an average brightness at 0°

and 90°

orientation and −

4°

entrance angle according to ASTM D4596-1a of at least 625 candelas/lux/m2 for an observation angle of 0.2°

, at least 375 candelas/lux/m2 for an observation angle of 0.5°

, and at least 80 candelas/lux/m2 for an observation angle of 1.0°

, wherein the sheeting is durable for outdoor use.

2. Retroreflective sheeting comprising an array of cube corner elements having a viewing surface and a backside, wherein the sheeting exhibits an average brightness at 0°

and 90°

orientation and −

4°

entrance angle according to ASTM D4596-1a of at least 625 candelas/lux/m2 for an observation angle of 0.2°

, at least 375 candelas/lux/m2 for an observation angle of 0.5°

, and at least 80 candelas/lux/m2 for an observation angle of 1.0°

, and the backside comprises a specular reflective coating.

3. 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.

4. Retroreflective sheeting comprising a pair of adjacent rows of preferred geometry cube corner elements wherein adjacent cube corner 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.