Roadway sign

• US 4,726,134 A
• Filed: 11/21/1986
• Issued: 02/23/1988
• Est. Priority Date: 11/21/1986
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Woltman, Henry L.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Conteras, Wenceslao J.
• Application Number:
  US06/933,739
• Time in Patent Office: 459 Days
• Field of Search: 350/103, 40/584, 40/615, 40/612, 40/454
• US Class Current: 40/582
• CPC Class Codes: G09F 13/0472 Traffic signs
• CPC Class Codes: G09F 13/16 Signs formed of or incorporating reflecting elements or surfaces, e.g. warning signs having triangular or other geometrical shape

Abstract

An improved roadway sign comprising a light retroreflective indicia region and colored retroreflective background region is provided. The retroreflective properties of the regions are selected such that the ratio of the retroreflective brightness of the indicia to that of the background is substantially larger at observation locations within the legibility zone for the sign, than the ratio is at observation locations outside the legibility zone. The sign is conspicuous by virtue of the bright retroreflection and distinctive color of the background outside the legibility zone, yet is legible because of the increased contrast ratio of the indicia to the background in the legibility zone.

Claims

1. A sign comprising a retroreflective background region and a retroreflective indicia region, wherein the retroreflective properties of said regions are selected such that the ratio of retroreflective brightness of said indicia to the retroreflective brightness of said background is substantially larger at locations within the legibility zone for the sign, than said ratio is at locations outside the legibility zone.

2. The sign of claim 1 wherein said ratio at observation locations within the legibility zone is at least 6:

1.

3. The sign of claim 2 wherein said ratio is at least 16:

1.

4. The sign of claim 1 wherein said indicia region is covered by microlens-based retroreflective sheeting.

5. The sign of claim 4 wherein said background region is covered by cube-corner-based retroreflective sheeting.

6. The sign of claim 1 wherein said background region is covered by cube-corner-based retroreflective sheeting.

7. The sign of claim 6 wherein said indicia region is covered by cube-corner-based retroreflective sheeting.

8. The sign of claim 1 wherein said indicia comprise retroreflective sheeting adhered over said background.

9. A sign comprising a retroreflective background region and a retroreflective indicia region, wherein the retroreflective properties of said regions are selected such that the ratio of retroreflective brightness of said indicia to the retroreflective brightness of said background is at least 10:

1 at an observation angle of 0.5°

, and said ratio is less than about 6;

1 at an observation angle of 0.1°

.