Security document including subtle image and system and method for viewing the same

• US 6,301,363 B1
• Filed: 10/26/1998
• Issued: 10/09/2001
• Est. Priority Date: 10/26/1998
• Status: Expired due to Fees

• Current Assignee: The Standard Register Company (Middleby Corporation)
• Original Assignee: The Standard Register Company (Middleby Corporation)
• Inventors: Mowry, William H. Jr.
• Primary Examiner(s): Swann, Tod
• Assistant Examiner(s): Smithers, Matthew
• Application Number:
  US09/179,075
• Time in Patent Office: 1,079 Days
• Field of Search: 380/51, 380/54, 283/17, 283/72, 283/73, 283/91, 283/93, 283/108, 283/113, 356/71, 359/619, 359/622, 359/623, 359/621
• US Class Current: 380/54
• CPC Class Codes: G07D 7/128 Viewing devices
• CPC Class Codes: G07D 7/206 Matching template patterns

Abstract

A system for viewing a subtle image on a security document is provided including a security document, a document viewer, and a document receiving station. The security document comprises a subtle image and a security image formed on a first face of the security document, wherein security image elements are arranged in a security image element array and complementary security image elements are arranged in a complementary security image element array. The subtle image comprises a plurality of subtle image elements arranged in a subtle image element array. The subtle image element array is arranged in a pattern that is optically distinct from respective patterns of arrangement of the security image element array and the complementary security image element array. The document viewer comprises a plurality of lens elements arranged in a lens element array, wherein the plurality of lens elements define a document viewer focal plane, and the lens elements within the lens element array are arranged to render the subtle image readily apparent to the naked eye by enhancing the appearance of the subtle image elements relative to the security image elements and the complementary security image elements and by degrading the appearance of the security image elements and the complementary security image elements relative to the subtle image elements. The document receiving station is positioned to receive the document such that the document may be positioned substantially in the document viewer focal plane.

Claims

1. A system for viewing a subtle image on a security document comprising:

a security document comprising a subtle image formed on a first face of said document, wherein

said subtle image is formed by a set of security image elements and a set of complementary security image elements,

one of said set of security image elements and said set of complementary security image elements is not readily duplicated by a photocopier at a predetermined photocopier setting, while the other of said set of security image elements and said set of complementary security image elements is readily duplicated by said photocopier at said predetermined photocopier setting,

said security image elements are arranged in a security image element array characterized by a first element array frequency f₁, and

said complementary security image elements are arranged in a complementary security image element array characterized by a second element array frequency f₂;

a document viewer comprising a plurality of lens elements arranged in a lens element array, wherein said plurality of lens elements define a document viewer focal plane, and said lens element array is characterized by a lens element array frequency f₀, where f₀, f₁, and f₂ satisfy at least one of the following document characteristic equations

2. A system for viewing a subtle image on a security document as claimed in claim 1 wherein f₀, f₁, and f₂ satisfy at least two of said document characteristic equations.

3. A system for viewing a subtle image on a security document as claimed in claim 1 wherein said lens element array frequency f₀ is substantially equal to a selected one of said first element array frequency f₁ and said second element array frequency f₂.

4. A system for viewing a subtle image on a security document as claimed in claim 1 wherein one of said first element array frequency f₁ and said second element array frequency f₂ is greater than the other of said first element array frequency f₁ and said second element array frequency f₂, and wherein said lens element array frequency f₀ is substantially equal to the lesser of said first element array frequency f₁ and said second element array frequency f₂.

5. A system for viewing a subtle image on a security document as claimed in claim 1 wherein said document receiving station is arranged to receive said document such that a selected one of said security image element array and said complementary security image element array is oriented along a first angle relative to said document receiving station and wherein said lens element array is oriented along said first angle.

6. A system for viewing a subtle image on a security document as claimed in claim 1 wherein a selected one of said security image element array and said complementary security image element array is oriented at a first angle relative to a longitudinal dimension of said document and wherein said document receiving station is positioned to receive said document such that said lens element array is oriented along said first angle relative to said longitudinal dimension of said document.

7. A system for viewing a subtle image on a security document as claimed in claim 6 wherein said lens element array frequency f₀ is substantially equal to the element array frequency of said selected element array.

8. A system for viewing a subtle image on a security document as claimed in claim 1 wherein said security image element array and said complementary security image element array are oriented at different angles relative to a longitudinal dimension of said document.

9. A system for viewing a subtle image on a security document as claimed in claim 1 wherein said lens element array comprises a lenticular lens sheet.

10. A system for viewing a subtle image on a security document as claimed in claim 1 wherein said lens element array comprises a succession of lens elements spaced adjacent one another at said lens element array frequency f₀.

11. A system for viewing a subtle image on a security document as claimed in claim 10 wherein respective ones of said lens elements have a longitudinal dimension and a partially convex cross section perpendicular to said longitudinal dimension, and wherein said cross section is substantially uniform along said longitudinal dimension.

12. A system for viewing a subtle image on a security document as claimed in claim 1 wherein said lens element array comprises a plurality of distinct lens element portions characterized by respective distinct lens element array frequencies f₀.

13. A system for viewing a subtle image on a security document as claimed in claim 12 wherein said distinct lens element portions are positioned to permit simultaneous alignment of said distinct lens element portions with corresponding distinct subtle image portions present on said security document.

14. A system for viewing a subtle image on a security document as claimed in claim 1 wherein said security image elements and said complementary security image elements are selected from a group consisting of lines, dots, non-uniform geometric shapes, and combinations thereof.

15. A system for viewing a subtle image on a security document as claimed in claim 1 wherein said subtle image comprises a repetitive array of warning terms.

16. A method of viewing a subtle image on a security document comprising the steps of:

identifying a security document comprising a subtle image formed on a first face of said security document, wherein

said subtle image is formed by a set of security image elements and a set of complementary security image elements,

one of said set of security image elements and said set of complementary security image elements is not readily duplicated by a photocopier at a predetermined photocopier setting, while the other of said set of security image elements and said set of complementary security image elements is readily duplicated by said photocopier at said predetermined photocopier setting,

said security image elements are arranged in a security image element array characterized by a first element array frequency f₁, and

said complementary security image elements are arranged in a complementary security image element array characterized by a second element array frequency f₂;

providing a document viewer comprising a plurality of lens elements arranged in a lens element array, wherein said plurality of lens elements define a document viewer focal plane and said lens element array is characterized by a lens element array frequency f₀, where f₀, f₁, and f₂ satisfy at least one of the following document characteristic equations

17. A system for viewing a subtle image on a security document comprising:

a security document comprising a subtle image and a security image formed on a first face of said security document, wherein

said security image comprises a set of security image elements and a set of complementary security image elements,

one of said set of security image elements and said set of complementary security image elements is not readily duplicated by a photocopier at a predetermined photocopier setting, while the other of said set of security image elements and said set of complementary security image elements is readily duplicated by said photocopier at said predetermined photocopier setting,

said security image elements are arranged in a security image element array,

said complementary security image elements are arranged in a complementary security image element array,

said subtle image comprises a plurality of subtle image elements arranged in a subtle image element array,

said subtle image element array is arranged in a pattern that is optically distinct from respective patterns of arrangement of said security image element array and said complementary security image element array;

a document viewer comprising a plurality of lens elements arranged in a lens element array, wherein said plurality of lens elements define a document viewer focal plane, and said lens elements within said lens element array are arranged to render said subtle image readily apparent to the naked eye by enhancing the appearance of said subtle image elements relative to said security image elements and said complementary security image elements and by degrading the appearance of said security image elements and said complementary security image elements relative to said subtle image elements; and

a document receiving station positioned to receive said document such that said document may be positioned substantially in said document viewer focal plane.

18. A system for viewing a subtle image on a security document as claimed in claim 17 wherein said lens elements within said lens element array are arranged to enhance the appearance of said subtle image elements by creating one of

a substantially positive image of said subtle image elements relative to said security image elements and said complementary security image elements and

a substantially negative image of said subtle image elements relative to said security image elements and said complementary security image elements.

19. A system for viewing a subtle image on a security document as claimed in claim 17 wherein:

said security image element array is characterized by a first element array frequency f₁;

said complementary security image element array is characterized by a second element array frequency f₂;

said subtle image element array is characterized by a subtle image element array frequency f₃;

said subtle image element array frequency f₃ has a value that differs substantially from said first element array frequency f₁ and said second element array frequency f₂; and

said lens element array is characterized by a lens element array frequency f₀, where f₀ and f₃ satisfy at least one of the following equations

20. A system for viewing a subtle image on a security document as claimed in claim 19 wherein said first element array frequency f₁, said second element array frequency f₂, and said subtle image element array frequency f₃ satisfy the following document characteristic equations

21. A system for viewing a subtle image on a security document as claimed in claim 17 wherein said lens element array comprises a plurality of distinct lens element portions.

22. A system for viewing a subtle image on a security document as claimed in claim 21 wherein said distinct lens element portions are positioned to permit simultaneous alignment of said distinct lens element portions with corresponding distinct subtle image portions present on said security document.

23. A method of viewing a subtle image on a security document comprising the steps of:

identifying a security document comprising a subtle image and a security image formed on a first face of said security document, wherein

said security image comprises a set of security image elements and a set of complementary security image elements;

one of said set of security image elements and said set of complementary security image elements is not readily duplicated by a photocopier at a predetermined photocopier setting, while the other of said set of security image elements and said set of complementary security image elements is readily duplicated by said photocopier at said predetermined photocopier setting;

said security image elements are arranged in a security image element array;

said complementary security image elements are arranged in a complementary security image element array;

said subtle image comprises a plurality of subtle image elements arranged in a subtle image element array;

said subtle image element array is arranged in a pattern that is optically distinct from respective patterns of arrangement of said security image element array and said complementary security image element array

providing a document viewer comprising a plurality of lens elements arranged in a lens element array, wherein said plurality of lens elements define a document viewer focal plane and said lens elements within said lens element array are arranged to render said subtle image readily apparent to the naked eye by enhancing the appearance of said subtle image elements relative to said security image elements and said complementary security image elements and by degrading the appearance of said security image elements and said complementary security image elements relative to said subtle image elements; and

positioning said document and said document viewer relative to one another such that said document lies substantially in said document viewer focal plane.

24. A security document comprising a subtle image and a security image formed on a first face of said security document, wherein:

said security image comprises a set of security image elements and a set of complementary security image elements;

one of said set of security image elements and said set of complementary security image elements is not readily duplicated by a photocopier at a predetermined photocopier setting, while the other of said set of security image elements and said set of complementary security image elements is readily duplicated by said photocopier at said predetermined photocopier setting;

said security image elements are arranged in a security image element array characterized by a first element array frequency f₁;

said complementary security image elements are arranged in a complementary security image element array characterized by a second element array frequency f₂;

said subtle image comprises a plurality of subtle image elements arranged in a subtle image element array characterized by a subtle image element array frequency f₃; and

said subtle image element array frequency f₃ has a value that differs substantially from said first element array frequency f₁ and said second element array frequency f₂, whereby, upon viewing said document with a document viewer having a plurality of lens elements arranged in a lens element array, said subtle image is rendered readily apparent relative to said security image.

25. A security document as claimed in claim 24 wherein said first element array frequency f₁ has a value that differs substantially from said second element array frequency f₂.

26. A security document as claimed in claim 24 wherein said subtle image element array and at least one of said security image element array and said complementary security image element array are oriented at different angles relative to a longitudinal dimension of said document.

27. A security document as claimed in claim 24 wherein said security image element array, said complementary security image element array, and said subtle image element array are oriented at different angles relative to a longitudinal dimension of said document.

28. A security document as claimed in claim 24 wherein said first element array frequency f₁, said second element array frequency f₂, and said subtle image element array frequency f₃ satisfy the following document characteristic equations

29. A security document as claimed in claim 24 wherein said subtle image is arranged to camouflage said security image.

30. A security document as claimed in claim 24 further comprising a camouflage image formed on said first face of said security document.

31. A security document as claimed in claim 24 wherein said subtle image is formed in a selected portion of said first face.

32. A security document as claimed in claim 24 wherein said subtle image and said security image are formed in a common area of said first face.

33. A security document comprising a subtle image and a security image formed on a first face of said security document, wherein:

said security image comprises a set of security image elements and a set of complementary security image elements;

one of said set of security image elements and said set of complementary security image elements is not readily duplicated by a photocopier at a predetermined photocopier setting, while the other of said set of security image elements and said set of complementary security image elements is readily duplicated by said photocopier at said predetermined photocopier setting;

said security image elements are arranged in a security image element array;

said complementary security image elements are arranged in a complementary security image element array;

said subtle image comprises a plurality of subtle image elements arranged in a subtle image element array;

said subtle image element array is arranged in a pattern that is optically distinct from respective patterns of arrangement of said security image element array and said complementary security image element array, such that an optical element may be arranged to render said subtle image readily apparent to the naked eye by enhancing the appearance of said subtle image elements relative to said security image elements and said complementary security image elements and by degrading the appearance of said security image elements and said complementary security image elements relative to said subtle image elements.

34. A security document processing system comprising a document issuing station and at least one document receiving station, wherein said at least one document receiving station comprises a system for viewing a subtle image on a security document, said system for viewing said subtle image comprising:

a security document comprising a subtle image formed on a first face of said document, wherein

said subtle image is formed by a set of security image elements and a set of complementary security image elements,

one of said set of security image elements and said set of complementary security image elements is not readily duplicated by a photocopier at a predetermined photocopier setting, while the other of said set of security image elements and said set of complementary security image elements is readily duplicated by said photocopier at said predetermined photocopier setting,

said security image elements are arranged in a security image element array characterized by a first element array frequency f₁, and

said complementary security image elements are arranged in a complementary security image element array characterized by a second element array frequency f₂;

a document viewer comprising a plurality of lens elements arranged in a lens element array, wherein said plurality of lens elements define a document viewer focal plane, and said lens element array is characterized by a lens element array frequency f₀, where f₀, f₁, and f₂ satisfy at least one of the following document characteristic equations