Abstract: The invention is to improvements in signature panels for credit cards or similar instruments. The signature panel is made from a foil having a carrier layer with a transferable signature panel layer having a coating composition incorporating a polymeric material. The signature panel layer can be transferred in response to heat and pressure onto a plastic substrate from the carrier layer providing a signature space. A security indicia is placed on or in the signature accepting surface, of the signature panel layer, using an ink to define a rainbow pattern.

Abstract: A transfer film for use, for example, with security documents includes a pattern defining layer having concavities defining an inverted relief pattern, and a retaining layer overlying and releasably filling the concavities of the pattern defining layer. The pattern defining layer is removable from the retaining layer to transfer the relief pattern from the pattern defining layer to the retaining layer.

Abstract: Raman-active compounds such as polydiacetylenes are provided in the form of particles whose maximum dimension is 40 .mu.m. They can be formulated into inks, for the purpose of printing on security documents which are thus readily capable of authentication.

Abstract: A self contained writing pad unit (1) comprises a pressure pad (7) for sensing movement of a writing instrument over a contact surface (2) of the unit when a user writes a sign, for example a signature, either directly on the contact surface or on a writing medium (4) supported by the contact surface. Electronics (8) including a RAM and timing systems determine data relating to the original signature. A power supply (9) is provided to enable operation of the electronics (8). The unit (1) is portable and the data represents dynamic characteristic features of the writing signature.

Abstract: A method and apparatus for exposing a pair of radiation sensitive surfaces to a beam of optical radiation is described. The apparatus comprises a support (20) for supporting the radiation sensitive surfaces which may be provided on opposite sides of an identification card. A laser (1) provides a laser beam which impinges on a pair of resonant scanners (10,11) which cause radiation impinging on their respective mirrors to be reflected onto opposite surfaces of the identification card. A control system (103) causes the mirrors of the scanners (10,11) to oscillate in quadrature. The laser beam passes through an A/O modulator (4) responsive to signals from the control system (103) to cause radiation to impinge alternately on one or the other of the scanners (10,11).

Abstract: A security card blank comprises a plurality of superposed layers (5,5',6,7,8,9) including a metallic layer (5,5'). The metallic layer comprises any radiation absorbent, metal, metalloid, or their alloys or derivatives, such as oxides or sulphides. The metallic layer (5,5') is positioned within the card blank and is imageable only under the influence of high intensity radiation to produce a security card. After imaging, at least part of the imaged metallic layer is detectable from outside the card.

Abstract: An electrical conductor array particularly for use in a pressure pad is described. The pressure pad comprises two electrical conductors arrays (3,5) of substantially parallel electrical conductors which are superposed and biased towards a spaced apart position with the conductors of one array transverse to the conductors of the other. One of the arrays (5) is responsive to applied pressure on the array to deflect against the bias towards the other array (3). At least one of the arrays (3,5) comprises a number of blocks of substantially parallel first conductors (12), the first conductors of each block being electrically connected to respective first common conductors (13); and, between pairs of first conductors (12) of each block, a respective second conductor (14), corresponding second conductors (14) from each block being electrically connected to a respective second common conductor (15).

Abstract: A method of determining whether the writer of a sign is the same as the writer of a previously written sign at least one characteristic feature of which has been prerecorded comprises: (a) detecting at least one characteristic feature of the written sign; (b) comparing the or each detected feature with the corresponding prerecorded feature (s); (c) generating an acceptance signal if all differences between the detected and the prerecorded features lie within first predetermined limits; (d) if an acceptance signal cannot be generated, obtaining one or more further written signs (up to a predetermined maximum) and repeating steps (a) to (c) with the or each further written signs; (e) if an acceptance signal cannot be generated for the or any of the further written signs, comparing the differences between the characteristic features of each written sign and the corresponding characteristic of the prerecorded sign and, if all the differences fall within second predetermined limits; (f) comparing corresponding cha

Abstract: This invention relates to documents, such as banknotes, which are produced and used in large numbers and which, for a given series, are identical one with another except for a unique multi-digit number upon each individual document, the number thus uniquely identifying that document within the series. According to the present invention, to render unauthorized reproduction of the document more difficult, on each document, at least two characters in the identifying number differ from each other (in addition to any differences in the letters or digits which they represent) in one or more visible characteristics. Thus the differing characters may have different heights or widths or be in different styles of type. Preferably, the identifying number appears twice on each document, in diagonally opposite corners, and preferably the variation of physical characteristics of the characters along the length of one of the numbers is reversed in direction in the other of the numbers.

Abstract: This invention concerns a prepayment metering system using a card on which information may be stored and from which stored information may be erased. In one form, a number (A) recorded on the card is read at the meter and stored (30) in preparation for the next card insertion. To obtain a further credit at the meter, the card is taken to a terminal station (12) at which the number (A) recorded on the card is read and is subjected to an encryption process under the control of a key and the resulting number (A') is recorded on the card in place of the previous number (A). On the next insertion of the card at the meter (21), the number (A') is read from the card and subjected to a decryption step (22) using the same key, the result of the decryption being compared with the number stored in the register (30) and in the event of a match a credit is issued.

Abstract: In a method of detecting sheets which do not have a genuine watermark (i.e. watermarks which result from variations in fibre distribution introduced during manufacture) the absorption of ultra-violet radiation is measured for each sheet in the area in which the watermark is expected to be present, and the transmittance of light by this area of the sheet is also measured. Sheets for which the absorption measurement does not show a substantially constant value, and sheets for which the light-transmittance shows a substantially constant value over the said area, are rejected. The absorption measurement is preferably effected by measuring the reflectance of ultra-violet radiation by the sheet, but the transmittance of ultra-violet radiation or the fluorescence of the sheet in the presence of ultra-violet radiation can also be measured. The measured value for the area can be compared with a reference value obtained by a measurement of the same parameter outside the watermark area.