Retroreflective sheeting
Assignee3M Innovative Properties Company
InventorsKenneth L. Smith, James R. Imbertson, John C. Kelliher, John A. Worrell, Sidney A. Ellingstad
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Abstract
The present application relates generally to retroreflective sheeting and the tools and methods used to make retroreflective sheeting. Microreplication tools and sheeting include controlled surface structure or haze. The surface structure or haze can be introduced, for example, by chemical etching of the tool surface and/or electroplating.
Claims38
Retroreflective sheeting, comprising:
- an array of cube corner elements wherein at an entrance angle of −4 degrees the sheeting exhibits a fractional retroreflectance slope of between about 3% and about 15% at an observation angle of about 0.5 degree.
Retroreflective sheeting, comprising:
- an array of cube corner elements that exhibits an average brightness at 0° and 90° orientation according to ASTM D4596-09 of between about 70 candelas/lux/m2 and 250 candelas/lux/m2 for an entrance angle of −4° and an observation angle of 0.2°, wherein the sheeting has a color of one of white or silver.
Retroreflective sheeting, comprising:
- an array of cube corner elements having an average surface roughness between about 0.0005 microns and about 0.0060 microns.
An article comprising at least one truncated cube corner element that is texturized.
A method of making retroreflective sheeting having an average brightness at 0° and 90° orientation according to ASTM D4596-1a of between about 70 candelas/lux/m2 and 250 candelas/lux/m2 for an entrance angle of −4° and an observation angle of 0.2°, comprising:
- texturing the surface of a tool that is replicated to form the retroreflective sheeting.
A method of making retroreflective sheeting that decreases light return over the full range of observation angles.
Dependencies are inferred from the claim text.