Identity document difficult to falsify and a process for manufacturing such a document

• US 4,790,566 A
• Filed: 10/11/1985
• Issued: 12/13/1988
• Est. Priority Date: 10/11/1984
• Status: Expired due to Fees

• Current Assignee: Matra
• Original Assignee: Matra
• Inventors: Glatigny, Alain, Boissier, Alain
• Primary Examiner(s): Bell, Paul A.
• Application Number:
  US06/786,853
• Time in Patent Office: 1,159 Days
• Field of Search: 283/89, 283/90, 283/91, 283/92, 283/93, 283/94, 283/904, 358/298, 358/282
• US Class Current: 283/91
• CPC Class Codes: B42D 2035/08 Alphanumerical data
• CPC Class Codes: B42D 2035/14 Dot or raster patterns
• CPC Class Codes: B42D 2035/20 Optical effects
• CPC Class Codes: B42D 2035/44 Miniaturised markings
• CPC Class Codes: B42D 2035/50 Corresponding markings appearing in different shapes or at different places
• CPC Class Codes: B42D 25/00 Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof printing processes to produce identification or security features B41M3/14
• CPC Class Codes: B42D 25/30 Identification or security features, e.g. for preventing forgery
• CPC Class Codes: B42D 25/405 Marking
• CPC Class Codes: B42D 25/485 by electronic processing means
• CPC Class Codes: Y10S 283/904 Credit card

Abstract

An identity document has graphical information printed on a support and including uncoded alphanumerical information which is specific to a holder of the document or to the document. The surface of the support is broken down into a network of macropixels each having a predetermined average light absorption level. Each of the micropixels in turn consists of a dot pattern matrix of micropixels each having a light absorption level selected among at least two predetermined levels and distributed for the average absorption of each of the macropixels to be said predetermined average light absorption level and for constituting a screen which reproduces on a microscopic scale part at least of the uncoded specific information.

Claims

1. Identity document having a support and graphical information printed ion said support, said graphical information including uncoded alphanumerical information visible to the naked eye and which is specific to a holder of said document or to said document,

wherein the graphical information consists of a network of a large number of macropixels each having a specific light absorption, and

wherein each of said macropixels consists of a dot pattern matrix of macropixels each having a light absorption selected among at least two predetermined light absorptions, whereby the light absorption of the macropixel is equal to the sum of the light absorptions of the micropixels in the matrix,

the micropixels having different ones of said predetermined light absorptions in the same one of said matrices and being distributed for reproducing part of said uncoded specific information on a microscopic scale in a directly readable form.

2. Identity document according to claim 1, wherein each of said macropixels consists of a dot pattern matrix of micropixels in sufficient number for representing an alphanumeric or graphic character of said screen within each macropixel.

3. Identity document according to claim 1, wherein said alphanumerical information consists of macropixels which are broken up into micropixels having predetermined light absorption levels selected for improving the definition of said graphical information.

4. Identity document according to claim 1, wherein each of said alphanumeric or graphical character of said screen is represented on a dot pattern rectangular matrix wherein each of said dots is a micropixel and wherein each alphanumeric or graphical character is eye readable and corresponds to the surface of a plurality of alphanumeric or graphical character is eye readable and corresponds to the surface of a plurality of alphanumeric or graphical characters in said screen, with a height which is of from 1 to 5 millimeters.

5. Identity document according to claim 1, wherein each of said alphanumeric characters of the screen is represented within one macropixel as a line of micropixels having a predetermined light absorption level, whereby each macropixel consists of micropixels whose light absorption is selected among three light absorptions only.

6. Identity document according to claim 5, wherein the light absorption levels available for constituting said macropixels are selected among a set of from 4 to 64 light absorption levels, extreme ones of said absorption levels being white and black, and wherein the graphical information carried by said document are in half tone from very high degree to very dark grey.

7. Identity document having graphical information printed on a support and including uncoded alphanumerical information which is specific to a holder of said document or to said document,

wherein said graphical information consists of a large plurality of macropixels each having a specific average light absorption level such that all of the macropixels represent the graphical information on a macroscopic scale, and

wherein said macropixels each consist of a dot pattern matrix of micropixels each having a light absorption level selected among at least two predetermined levels, the sum of the light absorption levels of the micropixels in the matrix being equal to the light absorption level of the respective macropixel, the whole of said matrix repetitively reproducing on a microscopic scale part at least of said alphanumerical specific information,

whereby correlation between reproductions of said specific information on a macroscopic scale and on a microscopic scale is achieved.

8. Identity document having a support and uncoded alphanumerical characters and pictures which are specific to a holder of said document on a surface of a support, wherein

said alphanumerical characters and pictures are printed on said surface as micropixels each having a light absorption level selected among a plurality of predetermined levels from white to black;

said micropixels are distributed into multiple adjacent rectangular matrices each forming a macropixel consisting of micropixels having only two levels among said plurality of levels, distributed to form, on a microscopic scale, an alphanumerical character;

the two levels of the micropixels in a macropixel are selected for the average absorption of said macropixel to represent an element of said alphanumerical characters and pictures having a light absorption level selected among a plurality of more than two predetermined values from light grey to dark grey;

and wherein the alphanumerical characters represented on a microscopic scale within said macropixels reproduce at least part of said uncoded alphanumerical characters in directly readable form.

9. A process for manufacturing an identity document having a graphic image including alphanumeric characters representing information in clear language and a background screen printed on a same support, comprising the steps of:

compressing the dynamic range of contrast of an original graphic image to be reproduced to reduce it to a contrast range lower than that which may be obtained as printed micropixels of predetermined size;

breaking down the graphic image up into macropixels having a dimension greater than that of the printed micropixels and each including the same predetermined plurality of micropixels;

computing the optical density to be given to each micropixel in each of said macropixels for representing on a microscopic scale one of a plurality of characters a screen correlated to said information and for leaving the overall contrast of the macropixel unchanged, and

printing the micropixels on the support.