U.S. patent number 3,862,501 [Application Number 05/368,528] was granted by the patent office on 1975-01-28 for documents verifiable as to their authenticity.
Invention is credited to Erik Gustav Elinder, Anton Wilhelm Jemseby.
United States Patent |
3,862,501 |
Jemseby , et al. |
January 28, 1975 |
DOCUMENTS VERIFIABLE AS TO THEIR AUTHENTICITY
Abstract
A document which can be verified as to its authenticity has
within at least two adjoining surface areas two similar patterns of
surface elements at least some of which are elongated, the pattern
of one surface area being displaced in relation to that of the
other surface area.
Inventors: |
Jemseby; Anton Wilhelm (183 42
Taby, SW), Elinder; Erik Gustav (115 21 Stockholm,
SW) |
Family
ID: |
20272724 |
Appl.
No.: |
05/368,528 |
Filed: |
June 11, 1973 |
Foreign Application Priority Data
|
|
|
|
|
Jun 16, 1972 [SW] |
|
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7948/72 |
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Current U.S.
Class: |
380/54; 283/93;
283/902 |
Current CPC
Class: |
G07D
7/20 (20130101); Y10S 283/902 (20130101) |
Current International
Class: |
G07D
7/00 (20060101); G09c 005/00 () |
Field of
Search: |
;35/2 ;283/11,17 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Wolfe; J. H.
Attorney, Agent or Firm: Flocks; Karl W.
Claims
What we claim and desire to secure by Letters Patent is:
1. A document verifiable as to its authenticity, comprising a first
surface area and a second surface area, adjoining said first
surface area, a first pattern of separate spaced apart image
elements within said first surface area, and a second pattern of
separate spaced apart image elements within said second surface
area, said first and second patterns being similar and having the
form of a moire pattern, the image elements of which correspond to
moire elements formed by photographic printing of a plurality of
superimposed and collectively printed screens which have
transparent screen apertures on a non-transparent background and at
least one of which has regularly arranged elongated screen
apertures, and said first pattern being displaced in relation to
said second pattern.
2. A document according to claim 1, wherein said first pattern is
displaced in parallel with respect to said second pattern.
3. A document according to claim 1, wherein said first pattern is
rotated in relation to said second pattern.
Description
Great efforts have been spent in making documents such as
banknotes, identity cards, passports etc., difficult to forge. All
of the solutions hitherto suggested for the verification of the
authenticity of documents are difficult to carry out and
time-consuming. The examination of adroit forgeries in the majority
of cases must be left to the experts.
One object of the present invention is to attain great safety in
making forgeries impossible and simultaneously to permit
verification of the authenticity of documents in a simple and rapid
manner for personnel transacting business over the counter, e.g.,
in banks, public offices etc. where the aforementioned types of
documents are handled and the authenticity thereof must be
ascertained.
Further objects of and the advantages gained by the invention will
appear from the following.
According to the basic inventive idea, a document according to the
invention within at least two adjoining surface areas has two
similar patterns of surface elements at least some of which are
elongated, and the pattern of one surface area is displaced in
relation to that of the other surface area. The authenticity of the
document is verified in a manner to be described hereinbelow with
the aid of a verification screen which corresponds to or is the
opposite of a screen film which has been used in the production of
the surface elements of at least one pattern on said document.
The invention will be more fully described hereinbelow with
reference to the accompanying drawings in which:
FIG. 1 diagrammatically and on a highly enlarged scale shows a
portion of a document having two different surface areas;
FIG. 2 on a highly enlarged scale shows a portion of a screen for
producing the surface areas in FIG. 1;
FIG. 3 on a highly enlarged scale shows a portion of a camouflage
screen for use with the screen in FIG. 2;
FIG. 4 on a highly enlarged scale shows a portion of a document
produced by means of the screens in FIGS. 2 and 3 in
superposition;
FIG. 5 by way of example shows a driving licence having surface
areas with various arrangements of surface elements;
FIG. 6 on a very highly enlarged scale shows a small portion of a
document in another embodiment of the invention;
FIG. 7 shows a screen used in producing the surface element
patterns illustrated in FIG. 6.
The portion on the document shown in FIG. 1 serves to illustrate
the basic inventive principle. Although the surface elements in
FIG. 1 have been shown for the sake of simplicity in the form of
lines, use is preferably made in practice of elongated elliptical
surface elements. The portion of the document shown in FIG. 1 has a
surface area with a regular checkered pattern of horizontally
elongated surface elements 1 which stand out in contrast to the
background and which in the embodiment chosen are equally large.
The surface area having the surface elements 1 surrounds a surface
area which is provided with a regular checkered pattern of
vertically elongated surface elements 2 which stand out in contrast
to the background and which in the embodiment chosen all are
equally large as the surface elements 1. The surface area having
the surface elements 2 in the embodiment chosen is in the form of a
crown.
The portion of the document shown in FIG. 1 has been produced in
the manner described hereinbelow by means of the screen 3 shown in
FIG. 2 and consisting of a film having elliptical transparent
surface elements 4 on a non-transparent background. The screen film
3 is placed in contact with the light-sensitive coat of a
photographic film and atop the screen film there is placed a
masking film which on a transparent background has a
non-transparent area in the form of a crown. The light-sensitive
film is exposed through the screen film and the masking film. Then
the masking film is removed, the screen film 3 is displaced by
turning it through 90.degree., another masking film which on a
non-transparent background has a transparent area in the form of a
crown is placed on the screen film, and a new exposure of the
light-sensitive film is made. The light-sensitive film is developed
and has the appearance shown in FIG. 1. It can then be fastened to
a suitable substrate in order itself to constitute the document, or
it can be used for making a printing plate by which the document is
printed on paper or other suitable document material.
The surface elements 4 on the screen film 3 should have a division
within the range customary in letterpress printing; on studying the
document portion shown in FIG. 1 with the naked eye the observer
cannot discern that there is a surface area having the form of a
crown in which the elongated surface elements 2 have a direction
different from that of the elongated surface elements 1 in the
surrounding surface area. If, on the other hand, a verification
screen corresponding to the screen film 3 according to FIG. 2 or
being the opposite thereof, that is, has non-transparent surface
elements on a transparent background is placed on the portion
according to FIG. 1, the crown is seen in strong contrast to the
surrounding surface area. If the verification screen is placed on
the portion according to FIG. 1 with the longitudinal direction of
the surface elements of the verification screen parallel with the
longitudinal direction of either the surface elements 1 or the
surface elements 2 in FIG. 1, the crown is seen in heavy contrast
to the environment as a surface area having a uniform degree of
brightness that considerably deviates from the uniform degree of
brightness of the environment. If the verification screen is placed
on the portion according to FIG. 1 with the longitudinal direction
of the surface elements of the verification screen at a certain
oblique angle to the longitudinal directions of the surface
elements 1 and 2 in FIG. 1, the crown and the environment display
moire effects heavily contrasting with one other and having
different patterns of moire bands. The effects obtained by means of
the verification screen are very sensitive to an exact agreement of
the verification screen with the screen film 3 which has been used
for producing the screen patterns on the document so that already
so small faults in the pattern positions of the surface elements as
will arise in a forgery made by photographing the screened surfaces
of a genuine document by means of a photographic camera are easily
discerned upon verification of the forgery with the aid of a
verification screen.
To obtain large and marked effects upon verification with the use
of verification screens, the surface elements 1 and 2 in FIG. 1
should suitably be at least twice as long as they are wide.
To make a forgery that cannot be discovered by means of the
verification screen the forger must have access to a screen film
that exactly corresponds to the film 3 in FIG. 2, and he must know
in which angular positions and in which positions of register the
screen film is to be used in producing the document. To render the
access to such screen films 3 difficult only the manufacturer of
the documents should possess such films, and the division of the
surface elements of the screen film and the shape of said surface
elements should deviate from the commercially available screen
divisions and surface element configurations. Moreover, the
verification screens, which are distributed for verification
purposes in great numbers to personnel transacting business over
the counter, should have a surface considerably smaller than the
entire surface of the documents that is provided with surface
element patterns. It is impossible to produce a satisfactory screen
film 3 by means of so small verification screen pieces.
To make it still more difficult to make forgeries the pattern of
the surface elements 1 and/or /or 2 in FIG. 1 should preferably
have superimposed upon it the pattern of camouflaging surface
elements. This can be realized by means of a screen film 5 as shown
in FIG. 3. This screen film on a non-transparent background has
transparent surface elements 6 which in the embodiment chosen are
circular and arranged in a regular checkered pattern and each of
which preferably has a considerably smaller surface than one of the
surface elements 4 in FIG. 3. On printing, as described above, for
producing the portion according to FIG. 1, not only the masking
film but also the screen film 5 is placed atop the screen film 3.
On printing the screen films 3 and 5 on the light-sensitive film,
surface elements of the appearance shown in FIG. 4 are obtained. In
this FIG. 4 the film 3 has been printed only in one position and no
masking film has been used for obtaining an area in the form of a
crown. The superimposed pattern of camouflaging surface elements
does not disturb the appearance of the document obtained with the
use of the verification screen. The camouflaging surface elements 6
of the screen film 5 can have a configuration other than the
circular configuration shown, and it is preferable to arrange the
surface elements 6 in an irregular or random pattern.
FIG. 5 shows a driving licence 7 which is embodied in accordance
with the invention Provided above a line 8 is an oblong surface
area 9 which contains a pattern (not shown) of for instance
vertically elongated surface elements of type 2 in FIG. 1. A
surface area 12 which is defined by boundary lines 10 and 11 and
shows a picture (not indicated of the owner of the licence, is
provided in the right-hand lower corner of the licence 7. The
picture is composed of surface elements 1 and 2 according to FIG.
1. The vertically elongated surface elements 1 are contained within
two surface areas indicated by dash lines 13 and 14 and being in
the form of crowns, while the horizontally elongated surface
elements 2 are contained within the remaining surface area of the
picture area 12. The surface elements 1 and 2 have, within the
picture area 12, been caused to give the visual impression of a
portrait in that the surface elements have been given varying sizes
in the manner customary in letterpress printing, that is, at the
exposure, described in connection with FIGS. 1 and 2 of a
light-sensitive film, light of exposure has been directed not only
through the screen film 3 and the masking film but also through a
transparent continuous-tone portrait picture in which case the
surface elements 4 of the screen 3 should be lenticular, for
instance according to Swedish Pat. No. 215,904. To render forgeries
difficult the surface area 14 lies partly inside and partly outside
the picture area 12. The driving licence 7 has an area lying within
dash-and-dot lines 15 which is reserved for text and signature, and
this area includes an annular surface area 16 the boundaries of
which are indicated by dash line circles and which is provided with
a pattern of vertically elongated surface elements of type 2 in
FIG. 1. Arranged within all surface areas of the driving licence 7,
except areas 9, 13, 14 and 16, is a pattern of horizontally
elongated surface elements of type 1 in FIG. 1. Within all surface
areas of the driving licence 7, the surface element patterns may
have superimposed on them camouflaging surface elements in the
manner described with reference to FIGS. 3 and 4, but no
camouflaged surface elements need be arranged within the picture
area 12.
On verification of the authenticity of the driving licence 7 a
verification screen film piece is placed over the right-hand
portion of the driving licence so as to cover the picture area 12
and the overlying part of the driving licence, and another
verification screen piece is placed over the surface area 16 and
the overlying part of the surface area 9. It is then possible
rapidly to establish that these parts of the driving licence that
have been selected for verification actually give the prescribed
visual impression when verification is made.
In an embodiment of the invention that is simple and advantageous
from the viewpoint of manufacture, one pattern of the document is
displaced in parallel with respect to the other pattern a distance
smaller than the distance measured in the direction of displacement
between the centers of two successive surface elements of the
pattern.
When a document according to this embodiment has a section that is
unique and identifying to the document and contains both patterns,
for instance a picture of the owner of the document, such as is the
case with driving licences, identity cards and passports, at least
one pattern can be composed of regularly arranged and substantially
identically conformed surface elements of the same or different
sizes. In the absence of such a unique and identifying section --
banknotes, the types of checks as at present customary, etc., have
no such section -- considerably greater possibilities are gained
towards preventing forgeries, without any complication of the
process of verifying the documents as to their authenticity by
means of a verification screen, by having at least one pattern
arranged as a moire pattern the surface elements of which
correspond to moire elements realized by photographic printing of
two or more superimposed and collectively printed screens which
have transparent screen apertures on a non-transparent background
and at least one of which has regularly arranged elongated screen
apertures.
The latter design is of particularly great interest and an
embodiment thereof is shown in FIGS. 6 and 7.
The portion illustrated in FIG. 6 of a document according to the
invention has a surface area 17 in the form of a posthorn, an outer
surface area 18 surrounding said posthorn, and an inner surface
area 19 within the posthorn loop. The mutual boundaries of these
surface areas are indicated in FIG. 6 by dash lines which do not
exist in the actual document but have been inserted in FIG. 6 in
order clearly to define the boundaries which would otherwise be
difficult to perceive in spite of the high enlargement in which the
portion of the document has been reproduced in FIG. 6. The free
surface areas in FIG. 6 are provided with similar patterns of
surface elements which in the embodiment chosen by way of example
are in the form of small black dots. These surface elements in a
regular way present different shapes and sizes within different
parts of FIG. 6. The majority of the surface elements in FIG. 6 are
elongated. They actually are moire elements which have been formed
in the manner more fully described hereinbelow. The surface
elements in the surface areas 18 and 19 belong to one and the same
pattern. The surface elements in the surface area 17 constitute a
pattern which corresponds to that in the surface areas 18 and 19
but which is displaced in parallel horizontally with respect to the
pattern in the surface areas 18 and 19 a distance which is
approximately half of the horizontal distance between the centers
of two successive surface elements of the pattern.
The surface elements in the surface areas 17-19 in FIG. 6 have been
produced in the following way by means of screens according to FIG.
7. The screen illustrated in FIG. 7 has transparent oval (or
rhombic) screen apertures 20 on a non-transparent background. The
screen is regular inasmuch as the centers of the screen apertures
lie at the crossings of two coordinate line systems the lines of
which are at the same mutual distances, the lines of one system
making oblique angles with those of the other system. When two
screens according to FIG. 7 are superimposed and rearviewed
different kinds of moire effects are perceived when one screen is
turned with respect to the other screen. In the embodiment shown in
FIG. 6 a moire effect has been chosen which has alternately
brighter and darker horizontal bands which are not, however,
particularly pronounced in FIG. 6 because of the high
enlargement.
A mask in the form of a transparent film having a non-transparent
portion in the form of a posthorn is placed on a light-sensitive
coat which is to be used for producing a printing plate for
printing a document according to FIG. 6, and two screens according
to FIG. 7 are placed upon said mask, one screen being turned with
respect to the other screen through such an angle that the desired
moire effect is obtained. The light-sensitive coat is then exposed
with light that is caused to fall heavily obliquely from one side
through the two screens and the mask. This will expose the surface
elements in the surface areas 18 and 19 according to FIG. 6. After
that, the described mask is removed and replaced with a mask which
is the opposite of the earlier used mask, that is, it has a
transparent posthorn portion but is otherwise opaque. A new
exposure of the light-sensitive coat is made with the screens in
unaltered positions, but the new exposure is made with light which
is caused to fall heavily obliquely from the direction opposite to
the earlier one through the two screens and the new mask. This will
expose the surface elements in the surface area 17 in FIG. 6. By
the fact that the exposure light in one exposure is incident for
example obliquely from the left as viewed in FIG. 6, and in the
other exposure obliquely from the right the surface elements in the
surface area 17 in FIG. 6 will be displaced horizontally with
respect to the surface elements in the surface areas 18 and 19.
After the two exposures the light-sensitive coat can be developed
and used in a known manner for producing a printing plate for
printing documents according to the invention.
These documents can be verified as to their authenticity, in the
same way as has been described above, with the use of a piece of
screen film of the kind illustrated in FIG. 7. When the screen film
piece is placed over the portion of the document illustrated in
FIG. 6 the posthorn earlier invisible to the naked eye will stand
out in clear contrast to the remainder of the document, and forged
documents are easily revealed by faulty moire effects and density
degrees on such verification with the aid of a screen according to
FIG. 7.
The difficulty of making forgeries increases if on producing the
moire surface elements in a document use is made of two screen
films of different embodiments so that one screen film does not
conform with the screen film pieces handed out for verification of
the documents to personnel transacting business over the counter.
It is practically impossible, on the basis of the moire patterns of
the documents, to try and establish the parameters of the screens
that have been used for the production of the patterns. A still
greater safety in this respect is gained if the patterns in FIG. 6
are produced by color printing and at least one pattern is produced
by iridiscent printing preferably in such a way that different
parts of the pattern have complementary colors, for instance purple
and bluish-green. A particularly good safety towards forgeries
being made is obtained when also at least one pattern in the manner
earlier described has superimposed on it the pattern of
camouflaging surface elements which have been produced by
iridiscent printing and have in at least some part of the document
a color other than that of the pattern, preferably a complementary
color. It is advantageous to print the camouflaging surface
elements with gloss ink and the pattern or patterns with a matte
ink or vice versa.
* * * * *