Printed matter – Having revealable concealed information – fraud preventer or... – Utilizing electromagnetic radiation
Reexamination Certificate
1999-04-08
2001-01-23
Gerrity, Stephen F. (Department: 3722)
Printed matter
Having revealable concealed information, fraud preventer or...
Utilizing electromagnetic radiation
C283S057000, C283S058000, C283S083000, C283S094000, C283S901000, C428S916000
Reexamination Certificate
active
06176522
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to security documents or tokens such as bank notes, travellers cheques, bonds, passports, and is particularly concerned with providing bank notes or other security documents or tokens with a low cost security device that has an attractive appearance whilst being difficult to duplicate.
BACKGROUND OF THE INVENTION
Australian Patent No 558476 discloses a method of producing a plastics bank note or security token or the like comprising a transparent polymeric substrate coated with layers of opaque material applied in such a way as to leave a transparent area which may include an optically variable security device, such as a diffraction grating, on an opaque, reflective layer of foil.
Whilst plastics bank notes with transparent areas including diffraction gratings as optically variable security devices, such as disclosed in Australian Patent No 558476, are difficult to reproduce, in low value plastics bank notes the process of incorporating diffraction gratings in the notes may be too costly or not felt to be needed.
It is therefore desirable to provide a bank note or other security document or token with a simpler, less expensive security device but which is still effective and difficult to reproduce.
It is also desirable to provide a method of, and apparatus for, producing bank notes or other security documents or tokens with low cost security devices that are difficult to reproduce.
It is further desirable to provide a plastics bank note or other security document or token with a security device that produces an optically variable effect when the note, document or token is rotated or viewed from different angles and which gives feel or texture to the note, document or token.
SUMMARY OF THE INVENTION
According to one aspect of the invention there is provided a bank note or other security document or token comprising a substrate having a part bearing printed and a transparent indicia-free portion including a security device wherein said security device comprises an embossing on said transparent portion forming an image which allows light to pass through, the image being visible under reflection and transmission of light from both sides of the bank note or other security document or token.
The embossing is preferably such that when the document is tilted or viewed from different angles with respect to a light source the embossed image will reflect and transmit more or less light as the document is rotated or viewed from different angles. When light passes through the embossing from the light source to the viewer in a direction substantially perpendicular to the surface of the transparent portion of the substrate, the embossed image is almost invisible, and as the viewing angle changes from the perpendicular, the embossed image becomes more highly visible. This gives the effect of the image changing, or switching on or off.
The embossing preferably comprises a regular matrix of embossed lines or dots or the like which together define the image. The embossed image may include one or more embossings deeper than other embossings and/or it may include embossed lines or series of dots extending at different angles to each other.
In a preferred embodiment the embossed image includes a first set of substantially parallel lines and a second set of substantially parallel lines extending at an angle with respect to the first set of parallel lines so that as the document is rotated or viewed from different angles relative to the light source the first set of parallel lines transmit more or less light than the second set of parallel lines.
Alternatively, or additionally, the embossed image may include embossed lines or dots of different depth, width or size so as to introduce different shapes into the image which become more or less evident as the document is rotated or viewed from different angles relative to a light source. Preferably, at least some of the lines, dots or other embossings are of a sufficient depth and/or width to be capable of detection by the naked eye and by touch. In a preferred embodiment of the embossings, the embossings are at least about 10 microns wide and about 10 microns deep.
According to another aspect of the invention there is provided a bank note or other security document or token comprising a substrate bearing indicia, said substrate having a portion of transparent plastics material carrying a security device, said security device comprises an embossed image formed on said transparent portion of plastics material, said embossed image being capable of detection by means of the naked eye and by touch. The embossed image may conveniently comprise a matrix of lines, dots or other embossings Preferably, the matrix of embossings includes one or more embossings deeper and/or wider than the other embossings. In a preferred embodiment, the matrix of embossings includes a first set of fine lines defining at least one shape which is more or less visible as the note, document or token is rotated or viewed from different angles, and a second set of deeper or coarser lines defining a shape which is able to be detected by touch. The fine lines of the preferred embodiment may, for instance, be about 40 microns deep and about 125 microns wide and generally U-shaped in profile, whereas the deeper or coarser lines are typically about 125 microns deep and about 500 microns wide and generally square shaped in profile. The deeper or coarser lines are preferably positioned or configured to provide protection of the other finer embossings against wear during use of the bank note or other security document or token.
Whilst the matrix of embossings are preferably provided wholly within a transparent, indicia-free portion of the bank note, document or token, it is also possible for the matrix of embossings to extend into an opaque area around or adjacent to the transparent portion so as to form a continuous image crossing the boundary between the transparent portion and the opaque area.
According to a further aspect of the invention there is provided a method of producing a bank note or other security document or token comprising the steps of: providing a substrate having at least a portion formed of transparent plastics material, printing indicia onto part of the substrate in such a manner as to leave the transparent portion of the substrate indicia-free, and embossing at least part of the transparent indicia-free portion to form an embossed image which allows light to pass through, the image being visible from both sides of the bank note or other security document or token.
Preferably, the transparent portion is embossed with a matrix of lines, dots or other embossings to define at least one shape that is visible in both reflection and transmission. The lines, dots or other embossings formed by the embossing process preferably produce an image which includes a plurality of different shapes which are more or less apparent as the note, document or token is rotated or viewed from different angles. In the embossing process, the transparent portion is preferably embossed with some lines, dots or embossings of greater depth and/or width than other embossings, and preferably at least the deeper and/or wider embossings are capable of being detected by means of the naked eye and by touch. In a preferred form of the process, the embossings are at least about 10 microns wide and about 10 microns deep.
In a preferred form of the invention, the embossings are formed in the portion of plastics material during the printing of at least part of the indicia onto the note, document or token, and most preferably by using an intaglio method to print said indicia.
The matrix of embossings are preferably formed by applying an embossing plate to the portion of the plastics material under heat and pressure. A convenient embossing temperature may fall substantially within the range from 70 to 85° C., preferably about 80° C., and a convenient embossing pressure may fall substantially within the range 30 to 40 MPa.
The document may be formed entirely from transparen
Foley & Lardner
Gerrity Stephen F.
Phan Daniel
Securency Pty Ltd
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