Retro-reflective sheet material

• US 3,924,929 A
• Filed: 03/06/1972
• Issued: 12/09/1975
• Est. Priority Date: 11/14/1966
• Status: Expired due to Term

• Current Assignee: Alfred H. Nellessen, Reynold E. Holmen
• Original Assignee: Alfred H. Nellessen, Reynold E. Holmen
• Inventors: Holmen, Reynold E., Nellessen, Alfred H.
• Primary Examiner(s): Wibert, Ronald L.
• Assistant Examiner(s): Tokar, Michael J.
• Application Number:
  US05/232,023
• Time in Patent Office: 1,373 Days
• Field of Search: 40/135 350/67,97-109 94/1.5
• US Class Current: 359/514
• CPC Class Codes: G02B 5/124 plural reflecting elements forming part of a unitary plate or sheet
• 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

A retro-reflective article having a retro-reflectivity of at least 400 candle power per foot candle per square foot when measured by a detector at an angle of 0.2 degrees divergence from an incident light beam and having a plurality of cube-corner retro-reflecting units and septa embossed on one surface, the septa being disposed to divide said surface into a multiplicity of separate sealable cells with a plurality of units in each cell.

Claims

2. A reflector structure according to claim 1 wherein a backing is hermetically bonded uninterruptedly to all the free edges of said septa to form a plurality of hermetically sealed cells enclosing said cube-corner retroreflecting units.

3. A reflector structure according to claim 1 wherein the hermetically sealed cells contain a particulate material of a size to afford substantially only point contact with the facets defining said cube-corner retro-reflecting units.

4. A cellular reflector structure having a plurality of individual adjacent cells for providing improved vandal-resistant reflectors, signs and legends having high retro-reflectivity and good daytime color appearance, said reflector structure comprising a monolithic body of transparent material having a light receiving front face having a smooth uninterrupted surface area extending over adjacent cells and a rear face having a rear surface area immediately opposite and coextensive with said uninterrupted front surface area, said rear surface area having a plurality of intersecting septa visible from said front face defining and isolating a plurality of polygonal cells each from the other and having a plurality of cube-corner retroreflecting units each having a set of three mutually perpendicular facets, each said cell having an area not greater than about one square inch and containing at least three of said cube-corner retroreflecting units and the combined area within said cells being not less than the combined area of said septa such that the retroreflectivity of said body is at least 400 candle power per square foot of area per foot candle of transmittable incident light, said septa having continuous free edges positioned rearward of the front face at least as far as said cube-corner retroreflecting units, which free edges permit the structure to be affixed to a backing to hermetically seal the cells individually, said cube-corner retroreflecting units being oriented in said cells to reflect light falling upon them through said front face back toward the source thereof to render said reflector structure highly visible at night and said septa improving the daytime appearance of the structure.

5. A retro-reflective article according to claim 4 wherein said article is of uniform thickness with said front surface smooth and planar, and with said free edges of said septa disposed in a plane parallel to said front face.

6. A retroreflective sheet material having a plurality of individual adjacent cells for providing improved vandal-resistant reflectors, signs and legends having high retroreflectivity and good daytime color appearance, said sheet material comprising a monolithic article of transparent material having a light receiving front face having a smooth uninterrupted surface area extending over adjacent cells and a rear face having a rear surface area immediately opposite and coextensive with said uninterrupted front surface area, said rear surface area having a plurality of intersecting septa visible from said front face defining and isolating a plurality of polygonal cells each from the other and having a plurality of cube-corner retroreflecting units each having a set of three mutually perpendicular facets, each said cell having an area not greater than about one square inch and containing at least three of said cube-corner retroreflecting units and the combined area within said cells being not less than the combined area of said septa, said septa having continuous free edges positioned rearward of the front face at least as far as said cube-corner retroflecting units, which free edges permit the structure to be affixed to a backing to hermetically seal the cells individually, said cube-corner retroflectiNg units being oriented in said cells to reflect light falling upon them through said front face back toward the source thereof to render said reflector structure highly visible at night and said septa improving the daytime appearance of the structure, and a backing hermetically bonded uninterruptedly to all the free edges of said septa of said monolithic article to form hermetically sealed cells enclosing said cube-corner units.

7. A retro-reflective sheet material according to claim 6 wherein said article is plate-like having a uniform thickness with said front surface being planar and with said cells having a uniform size.

8. A retro-reflective sheet material according to claim 6 wherein said sheet material comprises a plurality of said retro-reflective articles positioned in contiguous relationship, and wherein said articles are joined by a flexible material permitting the sheet material to be rolled or folded.

9. A retro-reflective sheet material according to claim 6 wherein the hermetically sealed cells contain a particulate material of a size to afford substantially only point contact with the facets defining said cube-corner retro-reflecting units.