Multiple structure cube corner article

• US 5,914,813 A
• Filed: 11/13/1997
• Issued: 06/22/1999
• Est. Priority Date: 10/20/1993
• 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., Benson, Gerald M.
• Primary Examiner(s): Phan, James
• Application Number:
  US08/969,241
• Time in Patent Office: 586 Days
• Field of Search: 359/529, 359/530, 29/527.3, 29/527.4, 29/557, 29/558, 409/131, 409/132
• US Class Current: 359/529
• CPC Class Codes: G02B 5/124 plural reflecting elements forming part of a unitary plate or sheet
• CPC Class Codes: Y10S 359/90 Methods
• CPC Class Codes: Y10T 29/49986 Subsequent to metal working
• CPC Class Codes: Y10T 29/49995 Shaping one-piece blank by removing material
• CPC Class Codes: Y10T 409/303752 Process

Abstract

A retroreflective cube corner article which is a replica of a directly machined substrate comprises a plurality of single cube corner elements which are machined in the substrate. Each cube corner element is bounded by at least one groove from each of three sets of parallel grooves in the substrate so that the article comprises a plurality of different geometric structures.

Claims

1. A retroreflective cube corner article having a base surface and a structured surface opposite the base surface which includes geometric structures therein defined by side surfaces from sets of parallel grooves, at least some of the geometric structures having an uppermost portion above the base surface at which exactly three approximately mutually perpendicular faces terminate, the three approximately mutually perpendicular faces being referred to as a cube corner element;

wherein the at least some of the geometric structures include a first and second cube corner element having noncongruent shapes; and

wherein at least one of the three approximately mutually perpendicular faces of at least one of the first and second cube corner elements has more than three sides.

2. The article of claim 1, wherein at least one of the three approximately mutually perpendicular faces of both the first and second cube corner elements have more than three sides.

3. The article of claim 1, wherein at least one of the three approximately mutually perpendicular faces of both the first and second cube corner elements have more than four sides.

4. The article of claim 1, wherein the first and second cube corner elements have, in plan view, base surfaces which are noncongruent.

5. The article of claim 1, wherein at least one of the three approximately mutually perpendicular faces of the first cube corner element has a different number of sides than at least one of the three approximately mutually perpendicular faces of the second cube corner element.

6. The article of claim 5, wherein at least one of the three approximately mutually perpendicular faces of the first cube corner element has a different number of sides than each of the three approximately mutually perpendicular faces of the second cube corner element.

7. The article of claim 1, wherein at least one of the three approximately mutually perpendicular faces of the first cube corner element is smaller than at least one of the three approximately mutually perpendicular faces of the second cube corner element.

8. The article of claim 1, wherein the uppermost portion comprises a cube peak formed by the three approximately mutually perpendicular faces.

9. The article of claim 1 wherein the at least some geometric structures further comprise a third cube corner element having a shape which is not congruent to that of either the first or second cube corner elements.

10. The article of claim 9, wherein the first, second, and third cube corner elements are interspersed throughout the structured surface.

11. The article of claim 9, wherein the first cube corner element neighbors the second and third cube corner elements.

12. The article of claim 9, wherein the first, second, and third cube corner elements have a first, second, and third peak respectively disposed at different heights above the base surface.

13. The article of claim 1, wherein the first and second cube corner elements have a first and second peak respectively disposed at different heights above the base surface.

14. The article of claim 1, wherein one side surface of a first groove includes one of the faces of the first cube corner element and one of the faces of the second cube corner element.

15. The article of claim 14, wherein one side surface of a second groove includes another of the faces of the first cube corner element and another of the faces of the second cube corner element.

16. The article of claim 1, wherein the sets of parallel grooves includes a first, second, and third set of parallel grooves, the first and second sets intersecting at a set of intersection points, the third set of parallel grooves including at least one groove that intersects the first and second sets at the set of intersection points and another groove that intersects the first and second sets at locations different from the set of intersection points.

17. A retroreflective cube corner article having a base surface and a structured surface opposite the base surface which includes geometric structures therein defined by side surfaces from sets of parallel grooves, at least some of the geometric structures having an uppermost portion above the base surface at which exactly three approximately mutually perpendicular faces terminate, the three approximately mutually perpendicular faces being referred to as a cube corner element;

wherein the at least some of the geometric structures include a first and second cube corner element having, in plan view, base surfaces which are noncongruent.

18. The article of claim 17, wherein the first and second cube corner elements have different active apertures.

19. The article of claim 17, wherein the uppermost portion comprises a truncated cube peak.

20. The article of claim 17, wherein the first and second cube corner elements have a first and second peak respectively disposed at different heights above the base surface.

21. The article of claim 17, wherein one of the faces of the first cube corner element and one of the faces of the second cube corner element are coplanar.

22. The article of claim 21, wherein another of the faces of the first cube corner element and another of the faces of the second cube corner element are coplanar.

23. The article of claim 21, wherein the at least some geometric structures further comprise a third cube corner element having a shape which is not congruent to that of either the first or second cube corner elements, and further wherein one of the faces of the third cube corner element is coplanar with the one of the faces of the first cube corner element and with the one of the faces of the second cube corner element.