Document with an optical diffraction safety element

Details Document with an optical diffraction safety element Document with an optical diffraction safety element

1989-02-15

1991-01-15

Bell, Paul A.

Printed matter

Having revealable concealed information, fraud preventer or...

Utilizing electromagnetic radiation

350 361, 283904, B42D 1500

Patent

active

049848240

ABSTRACT:
A document with an embossed macroscopic structure and acting through optical diffraction is disclosed. The structure, which serves as a security element comprises a plurality of surface portions with predetermined relief structures having spatial frequencies of over 10 lines/mm. Each surface portion is different from directly adjoining surface portions and at least some of the surface portions have a maximum dimension of less than 0.3 mm. To the naked eye, the pattern of surface portions on the document appears as a mesh of dots and lines. However, to an examiner with a magnifying device, the dots and lines appear as numbers, characters or other graphic features.

REFERENCES:
patent: 3819911 (1974-06-01), Greenway
patent: 3894756 (1975-07-01), Ward
patent: 4184700 (1980-01-01), Greenaway
patent: 4402571 (1983-09-01), Cowan et al.
patent: 4417784 (1983-11-01), Knop et al.
patent: 4563024 (1986-01-01), Blyth
patent: 4568141 (1986-02-01), Antes
patent: 4652015 (1987-03-01), Crane
patent: 4725111 (1988-02-01), Weitzen et al.
patent: 4735670 (1988-04-01), Maurer et al.
patent: 4761253 (1988-08-01), Antes
patent: 4790566 (1988-12-01), Boissier et al.
patent: 4814594 (1989-03-01), Drexler
patent: 4892385 (1990-01-01), Webster, Jr. et al.
Caulfield, "The Wonder of Holography", National Geographic, vol. 165, No. 3, Mar. 1984, p. 364.

Affiliated with

Also associated with

Rating

Document with an optical diffraction safety element does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Document with an optical diffraction safety element, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Document with an optical diffraction safety element will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-50947