Anti-counterfeiting see-through moire security feature using frequency-varying patterns

• US 20040084893A1
• Filed: 10/30/2002
• Published: 05/06/2004
• Est. Priority Date: 10/30/2002
• Status: Active Grant

• Current Assignee: Elesta Relays GmbH, Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Wang, Shen-ge, Fan, Zhigang
• Granted Patent: US 7,429,062 B2
• Time in Patent Office: Days
• US Class Current: 283/72
• CPC Class Codes: B42D 25/342 Moiré effects
• CPC Class Codes: Y10S 428/916 Fraud or tamper detecting
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

Frequency varying patterns are aligned on the front and back surfaces of a document to provide an anti-counterfeiting security device. The frequency varying patterns are reversed images. The document is sufficiently transparent to allow see-through of the pattern on the back of the document to be superimposed on the pattern on the front of the document. The frequency varying patterns will form a moire pattern if misaligned, regardless of the magnitude and the orientation of the misalignment.

Claims

1. A security feature for a document comprising

a first pattern of a plurality of first lines of varying frequency, said first pattern on a first surface of said document, and

a second pattern of a plurality of second lines of varying frequency, said second pattern on a second surface of said document, said second surface of said document being opposite said first surface of said document, said second pattern being a reverse of said first pattern, said document being sufficiently transparent wherein said first pattern and said second pattern are see-through such that said first pattern and said second pattern can be viewed superimposed upon each other from said first surface of said document or said second surface of said document, wherein if said first pattern is aligned with said second pattern, said first pattern or said second pattern is visible, if said first pattern is misaligned with said second pattern, a moire pattern is formed by said first pattern and second pattern is visible.

2. The security feature for a document of claim 1 wherein said first lines and said second lines vary in frequency across the transverse distance of said first lines and said second lines.

3. The security feature for a document of claim 1 wherein said first lines and said second lines vary in frequency across the length of said first lines and said second lines.

4. The security feature for a document of claim 1 wherein said first pattern and said second pattern are straight lines.

5. The security feature for a document of claim 1 wherein said first pattern and said second pattern are concentric circular lines.

6. The security feature for a document of claim 1 wherein said first pattern and said second pattern are a plurality of straight lines extending radially from a central point.

7. The security feature for a document of claim 1 wherein said first pattern and said second pattern are alphanumeric characters.

8. The security feature for a document of claim 1 wherein said first pattern and said second pattern are graphic illustrations.

9. The security feature for a document of claim 1 wherein said first pattern and said second pattern are adjacent to printing on the first surface and/or the second surface of said document.

10. A security feature for a document comprising

a first pattern of a plurality of first lines of varying frequency, said first pattern on a first surface of said document, and

a second pattern of a plurality of second lines of varying frequency, said second pattern on a second surface of said document, said second surface of said document being opposite said first surface of said document, said second pattern being a reverse of said first pattern, said document being sufficiently transparent at said first pattern and said second pattern wherein said first pattern and said second pattern are see-through such that said first pattern and said second pattern can be viewed superimposed upon each other from said first surface of said document or said second surface of said document, wherein if said first pattern is aligned with said second pattern, said first pattern or said second pattern is visible, if said first pattern is misaligned with said second pattern, a moire pattern is formed by said first pattern and second pattern is visible.

11. The security feature for a document of claim 10 wherein said first pattern and said second pattern are on a plastic area of said document.

12. The security feature for a document of claim 11 wherein said document surrounding said first pattern and said second pattern is paper.