Identification cards

Abstract: An ID card which comprises an opaque base which has adhered thereto a sheet which comprises an easy to recognise representational image (10) of the person to whom the card relates and at least one modulated image (11) which bears a recognisable relationship to the representational image but which has been altered with respect to its density and/or colour and/or spatial characteristics. Preferably the altered image has been modulated electronically.

Description: This invention relates to identification cards (I.D. cards) which comprise security features. It is becoming increasingly important to incorporate security features in I.D. cards to prevent copying and alteration. Various security features have been proposed such as water-marks and patterned lines. Also various inks and printed images have been proposed which exhibit fluorescence under special lighting conditions or which are only visible in U.V. or infra-red light. It is the object of the present invention to provide an I.D. card which comprises a novel security feature which is easy to produce but which is very hard to copy satisfactorily and which can be seen in daylight. Attention is drawn to European Patent Application 283233, to French Patent Application 1281252 and to French Patent Application 2611102 all of which relate to I.D. cards incorporating security features. However, in E.P. 283233 the card carries a modulated holographic image. In F.P. 1281252 the printed image and the modulated image are not of the person to whom the I.D. card relates. F.P. 2611102 relates to a method of forming a representational image of the I.D. card holder on an I.D. card using a high definition video-signed. Therefore according to the present invention there is provided an I.D. card which comprises an opaque base which has adhered thereto a sheet which comprises an easy to recognise representational image of the person to whom the card relates and at least one modulated image which bears a recognisable relationship to the representational image but which has been altered with respect to its density and/or colour and/or spatial characteristics, the I.D. card being characterised in that the representational image (10) is a three colour image of the person, the modulated image (11) is a single colour separation image of the person which is lighter in density than the representational image and the modulated image partially overlaps the representational image. By three colour image is meant an image which exhibits the three primary colour blue, green and red as well as the three secondary colours yellow, magenta and cyan. Usually both in printing and in photography a subtractive colour system is used and the dyes which form the three colour image are yellow, cyan and magenta. However, the single colour separation image present in the I.D. card of the present invention may be a blue, cyan, green, yellow, red or magenta image. The three colour image and the single colour separation image of the person may have been formed on the sheet by a printing process wherein three colour separation photographic negatives are prepared of the person and three printing blocks are prepared from these negatives. To prepare the three colour image each of these blocks having been treated with the appropriate coloured ink are printed in register on the sheet. To prepare the single colour separation image one of these blocks is inked and printed on the sheet. For example to prepare a green image both the yellow and the cyan blocks are inked and printed in register. Usually however the said sheet which carries both the three colour image and the single colour separation image is photographic colour paper. This sheet may be exposed either from photographic negatives or via an electronic signal storage system. If it is to be imaged using photographic negatives a full-three-colour photographic negative of the person is prepared and using a light-filter a single colour separation is prepared, the appropriate light filter being chosen for the required colour of the single colour separation image. Then the colour photographic material is printed using the two negatives. Most preferably however the image of the person is captured on a video camera, digitised and stored as the blue, red and green records of the image. When the representational image is required these records are used to form in turn blue, green and red components of the representational image which may be produced as a black and white image or as a full three colour image. Then in real time all three of the blue, red and green records are used to prepare the processed image or images. For example the green image only may be employed and its density lightened so there is formed on the sheet a three colour clear representational image of the person and a lightish green image of the person. In another case the red image also may be employed and its density lightened so there is formed on the sheet a three colour clear representational image of the person to whom the card relates, a lightish green image of the person and a lightish red image of the person. Another form of processed image may be a very small image of the person compared with the representational image or a very large enlargement of part of the image of the person as long as this enlargements can be recognised as relating to the representational image. A further form of the processed image would be made at a considerably lower resolution than that of the original image. Thus, if the image of the subject was represented in the final security card by, say, 40,000 pixels, an image of noticeably lower resolution, but still bearing a resemblance to the original subject, could be formed using 10,000 pixels, each pixel being 2 x the linear or 4 x the area dimension of the original pixel. This would produce an image which could appear to be made of a plurality of tiny coloured blocks. As stated preferably the sheet which carries the images is a piece of colour photographic material and the images are formed by a photographic chromogenic process or by using a silver dye bleach colour paper. However when the images are stored in digital form the images on the sheet may be formed using an ink-jet printer, a heat colour transfer printer or any other method used to form visible images from stored digital records of images. A method of obtaining an I.D. card according to the present invention using an electronic signal storage system is described hereinafter. Preferably the sheet which carries the images of the relevant person also carries other relevant information in alpha-numeric symbols. For example the persons name, the organisation, the department and possibly an address and the birth date of the person. The company's logo may also appear on the sheet. Most preferably however there is incorporated in the I.D. card between the sheet which carries the images and the protective overlay a hologram which covers completely the sheet which carries the images. This hologram is a reflection hologram but on a transparent base. This hologram may carry the company's logo and or/a striped pattern to render copying even more difficult. The card may be embossed to enable it to carry further information. Preferably the opaque base is composed of a plastics material such as pigmented polyvinyl chloride or polyester. To this is laminated by use of an adhesive the sheet which carries the images and to this either the film which contains the hologram or in its absence the light transparent protective overlay sheet which may be cellulose triacetate or polyester. The adhesive used and the method of lamination employed should be such that the I.D. card can not become delaminated without destroying the individual sheets from which it is made. A particularly useful method of bonding the assembly is that described in European patent 273012. The back surface of the I.D. card may carry machine readable information in either analogue or digital form. Usefully this information is cross-checkable with the alpha-numeric or embossed information on the front of the card, or is cross-checkable with the information contained in the hologram if such be present. The following drawings will serve to illustrate the invention. Figure 1 is block diagram of the apparatus required to prepare an I.D. card according to the present invention. Figure 2 is a top plan view of an I.D. card according to the present invention. Figure 3 is an exploded side view of the I.D. card of figure 2. In figure 1 there is shown a person 1 being photographed using a video camera 2. This photographic record is stored as blue, red and green separation records of the image in a storage device 3. Attached to the device 3 is a video processor 4. A computer 5 can also feed information to the processor 4. The output of the video processor 4 goes to a colour monitor 6 which is a T.V. screen and output from this goes to the video printer 7. Output from the printer 7 is used to form the images of the sheet 8. The video camera 2 in this case uses beam splitters and filters in its interior and stores the red, green and blue records of the captured image in pixel arrays of charge coupled device in the storage device 3. The computer stores the alpha-numeric data which is to be associated with each person being photographed. This may include data applicable to a large number of persons such as the name of the company and its address and personal data such as the name of the person, the birth date and position of the person in the company. In order to prepare the processed image, if for example the electronically processed image to be used is a lightish green image of the person, the green record is then fed to the video processor and this record is electronically processed to lighten overall the image. This lightened record is then stored. Thus to prepare an I.D. card the three colour stored records of the image of the subject, the modulated image and the alphanumeric information and logo are fed to the video processor, together with the stored altered green record and the relevant alpha-numeric information from the computers in the approximately correct spatial relationship. These features are then viewed on the monitor 6 on which they will appear as they will be printed on the sheet 8. If the lay-out appears to be satisfactory then the signals are fed from the video processor to the video printer 7 via a digital to analogue converter. The printer 7 in this case prints by using visible light. Thus the stored red record is printed through a red filter pixel by pixel on to the photographic colour material sheet 8. This is followed by the green record and finally by the blue record. The altered stored green image is printed through a green filter. After photographic processing the sheet 8 appears as shown in Figure 2. On this card is shown the representational image 10 of the person 1. This is a full three colour photographic image. There is also shown the processed image 11 which is a light green separation image of the three colour image 10. The processed image 11 partially overlaps the representational image 10. As can be seen the processed image 11 is an altered image of image 10 but bears a recognisable relationship to image 10. It has been found that it is very difficult to forge an I.D. card which carries both a representational image which identifies clearly the card holder and a processed image which has been derived from the representational image. Figure 3 shows an exploded view of the fully prepared card 13 which comprises a transparent cover sheet 14, a white pigmented plastics material base 15, the sheet 8 prepared as just described, a film 16 which is transparent and contains a holographic record of the relevant company, and a transparent cover sheet 17 which acts to protect the film 16 and the sheet 8. These five sheets are then laminated together using the adhesive described in E.P. 273012 so that the assembled card 13 can not be delaminated without tearing either or both sheet 8 and film 15.

Claims: An I.D. card which comprises an opaque base (8) which has adhered thereto a sheet which comprises an easy to recognise representational image of the person to whom the card relates and at least one modulated image which bears a recognisable relationship to the representational image but which has been altered with respect to its density and/or colour and/or spatial characteristics, the I.D. card being characterised in that the representational image (10) is a three colour image of the person, the modulated image (11) is a single colour separation image of the person which is lighter in density than the representational image and the modulated image partially overlaps the representational image. An I.D. card according to any claim 1, characterised in that the modulated image or images have been modulated electronically. An I.D. card according to claim 1 characterised in that the sheet which carries the images is a sheet of colour photographic paper. An I.D. card according to claim 3 characterised in that the photographic paper is silver dye bleach material. An I.D. card according to claim 1 characterised in that the sheet which carries the two images also carries alpha-numeric information which has been printed electronically from a computer store. An I.D. card according to claim 1 characterised in that it comprises a protective layer of transparent film material (14) the sheet which carries the images, a pigmented plastics material base (15) and optionally a protective layer of transparent film material (17) on the base distal to the said sheet. An I.D. card according to claim 6 characterised in that there is present between the protective transparent layer and the said sheet a sheet of a transparent hologram (16).

Inventors: MILLER DAVID WILLIAM, STEELE KEITH CHRISTOPHER, MILLER, DAVID WILLIAM, STEELE, KEITH CHRISTOPHER
Applicants: PMI DATA LTD, PMI DATA LIMITED
Application year: 1989
Main classification: B42D15
IPC codes: B42D15