Non-orthogonal cube corner elements and arrays thereof made by end milling
Assignee3M Innovative Properties Company
InventorsNelson D. Sewall, Christopher S. Grinde, Todd A. Ballen, Kenneth L. Smith
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Abstract
A new technique for making cube corner elements that involves end milling is used in the fabrication of cube corner elements having non-orthogonal dihedral angles and dihedral angle errors, and arrays of such cube corner elements. A given optical face of a cube corner element may be a compound face with two constituent faces. In some cases, the constituent faces may be parallel and coplanar such that a given dihedral angle error pertains to the entire optical face, while in other cases, the two constituent faces may not be parallel, and may be associated with different dihedral angle errors.
Claims10
An article comprising a structured surface that extends along a reference plane, the structured surface comprising a first cube corner element and remaining cube corner elements, the first cube corner element having a first, second, and third optical face;
- wherein none of the remaining cube corner elements are the first cube corner element;
- wherein at least part of the first optical face of the first cube corner element deviates from orthogonality relative to at least a part of the second optical face of the first cube corner element by a first angle error whose magnitude is at least 1 minute of arc but no more than 2 degrees;
- wherein the at least part of the first optical face of the first cube corner element is not coplanar with any optical face, or portion thereof, of any of the remaining cube corner elements that are adjacent to the first cube corner element, and
- wherein the first optical face of the first cube corner element is connected to an optical face of an adjacent cube corner element by a rounded edge, the rounded edge extending along an axis that is inclined relative to the reference plane.
Dependencies are inferred from the claim text.