AU604671B2 - Data-carrier in card form and method of producing it - Google Patents

Abstract

Record carriers on the basis of layers of plastic having features in the form of patterns or characters, the light-dark contrast of which changes from incident light to transmitted light, which are available in the form of information which is applied with the aid of a laser beam and modifies the optical characteristics of the record carrier material, the visual impression of which is different when viewed in incident light from that when viewed in transmitted light, and a method of producing said record carriers by generating information having a different visual impression by destroying a pigment which is dispersed in the substrate and absorbs and/or reflects the light with formation of light-permeable reaction products with the aid of a laser beam in the substrate.

Description

!11I 1I1 1.8 1.25 1.4 1.

068L99VEiZ z~M ns cj 1! 3ap) Z),XMAniS80dONW~mrH9a1DV 'id 01 I IJ I 1 I -I I I I 1111 1111 1 8 1111!25 1.4 _111.

I 1 1 l I I I I I ,I CO0M MO0N WE AL TH 6F AUS T RA LI A PATENT ACT 1952 COMPLETE SPECIFICATION 6 0'46~7 1 (original) FOR OFFICE USE Class Int. Class Application Number: Z?01; Lodged: Complete Specification Lodged: Accepted: Published: Priority: Related Art: 9 99 999 9 99.94 9999 9 4499 o #9 99 9 99 9 99 99 9999 9 9 *.s 4 99 99 4 4 94 944 4 94 9 9 9 This document contai'ns the amcndmenits mnade iiikr Sectioil 49 andl ii coi'rect for printing.

Name of Applicant: Address of Applicant: Actual Inventor(s): Address for Service: MAURER ELECTRONICS GMBH and LEIGH-MARDON PTY. LIMITED Nymphenburger Strasse 154, D-8000 Munich 19, FEDERAL REPUBLIC OF GERMANY; and 71-79 Macquarie Street, Sydney, New South Wales 2000, AUSTRALIA; respectively Thomas MAURER DAVIES COLLISON, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000.

Complete Specification for the invention entitled: "1DATA-CARRIER IN CARD FORM AND METHOD OF PRODUCING IT"1 The following statement is a full description of this invention, including the best method of performing it kri.,wn to us

-I-

To: THE COMMISSIONER OF PATENTS To: THE COM M ISSIONER OF PATENTS (a member of the firm of DAVIES COLLISON for and on behalf of the Applicant).

Davies Collison, Melbourne and Canberra.

-2 2 "DATA-CARRIER IN CARD FORM AND METHOD OF PRODUCING IT" The invention relates to security markings for a datacarrier in the form of a card based on plastic coatings with characteristics in the form of patterns or symbols.

Securities, such as for example banknotes or cheques, i and identity documents such as credit cards, identity cards, bank cards and the like, must be protected by 0, special authenticity characteristics against dishonest Sactions such as falsification and forgery. For exampie, 15 known data-carriers in the form of cards, such as credit °cards, identity cards, bank cards and the like are provided with a transparent covering foil which in the first place prevents the data entered on the data-carrier (text, images, logos, patterns, emblems and the like) from 'becoming illegible or unrecognizable through soiling or wear in the course of normal use and also prevents the possibility of altering or forging the data by simple means and with little trouble. There is a fundamental need in the case of data-carriers which are so widely used nowadays for these to be protected as far as possible against falsification, reproduction and/or complete forgery. It should be possible in this case for the attempt at falsification to be detectable reliably and without complicated testing methods and as far as possible also for lay persons without any additional testing devices or apparatus to be able to distinguish between the "genuine" data-carrier and the forgery.

Three characteristic demands are often made of identity documents, and therefore also of data-carriers in the form of cards of the type to which the invention relates, namely 909k4.TOCO 25.LET.68005.spe.2 i ~/vr Oj t were the s application made in a Convention country in respect of the invention the subject -rr.he application.

Insert place and date of signature.

Signature of declarant(s) (no aftestation required) Note* Initial all alterations, Declared at Sydney this 12t1 day of une, 1990 DAVIES COLLISON, MELBOURNE and CANBERRA.

c 2o-- 1. each identity document should be capable of being associated unfalsifiably and clearly with a system; 2. each identity document should represent a unicum, and 3. each identity document should contain unfalsifiable personal data of the owner of the identity document.

I9O4,Tac025.LET,68005.spe.2 i r31 -3- Association with a specific system is earoc re by specific symbols, for example logos, which as far as possible, i.e. when there are stringent demands for security, are represented by specific authenticity characteristics watermarks) or specific forms of an authenticity characteristic watermarks in the form of a logo, as in the case of the Eurocheque card).

To make difficult or prevent falsifications the informationcarrier can be supported by various measures using techniques known from the printing of securities or banknotes, for example by the use of a data-carrier in the form of a card with an 0o o inset of watermarked paper in the card, this insert possibly being printed with so-called guilloches in a plurality of O0O colours, as is known, for example in the case of cheque cards.

0°o0 This safety or authenticity characteristic, like the watermark o 0 or guilloche printing in the case of banknotes, can be produced o0o40 only by complicated processes and are therefore very difficult to imitate, which of course does not exclude the possibility of attempts at falsification in this respect. In addition, the possibility exists of removing the covering foil, by which means *an alteration of the data becomes possible.

An identity card is known from German Patent 29 07 004 which comprises two covering foils, at least one of which is transparent, and a card insert made of an opaque material, in 4 particular paper, which is provided with visually recognizable information which is applied to the insert through the transparent covering foil by means of a laser beam. Through the use of the laser beam the substrate lying beneath the transparent covering foil is blackened, in which case, through the partial destruction of the substrate material corresponding to the information applied, the possibility of falsification by removing the covering foil can be prevented. Naturally, an identity card of this kind makes possible the use of an additional authenticity characteristic in the form of a watermark only as lonq as a paper printed with a watermark or an insert jR 7 foil provided with a watermark is used as the card insert.

A

N

watermark of this kind can, however, be falsified by removing the transparent foil.

iSince the watermark for securities is regarded in security '.echnology as an authenticity characteristic of high security value, a considerable need exists for datacarriers in the form of cards of the type mentioned above to be provided with an authenticity characteristic comparable with the watermark in banknotes, but so far this has not been possible in the case of data-carriers in the form of plastic cards of the type mentioned above. Thus up to the present plastic identity cards with "watermarks" are i not known. By "watermark" in this case is to be understood a pattern or image which is barely discernible on observation in reflected light, but appears as a distinctly visible pattern or image, which may be in several shades of grey, in transmitted light.

On account of the manufacturing process such forms of authenticity characteristics, within the manufacturing tolerances, are the same in all documents of a system; i.e.

a clear identification of the individual document (unicum) is not possible in the case of authenticity characteristics of conventional type such as the watermark. In securities and identity cards this "unicum property" is achieved by a serial numbering of the document which is relatively easy to falsify and alter.

In the case of identity cards capable of automatic production, methods of producing the unicum properties are known which make use of the cloudiness of the substrate or magnetic patterns present on a magnetic track. These methods have the disadvantage either that appropriate production methods are necessary, or that the unicum characteristic is produced in a random manner, i.e. in a way impossible to control. Moreover, these methods are not suitable for visual identification of authenticity.

'11900904 ,T0C025.LET.68005.Bpe,4

L{,

cli. An identity card with characteristics that can be examined by reflected or transmitted light and a method of producing it are known from German Offenlegungsschrift 32 31 460. This identity card comprises at least two adjoining plastic coatings of different transparency, at least one of these coating bearing depressions corresponding to the patterns or symbols which are filled by the material of the adjacent plastic coating to at least part of their depth, whereby the light dark contrast intended is achieved. This identity card has the disadvantage that this authenticity characteristic in the form of the different light dark contrast in direct i (reflected) light or transmitted light must be created during the production of the card blank and cannot be in the form of card-specific or person-specific data and thus does not make possible the degree of security sought.

An extremely high degree of security against falsification and forgery of the data relating to a person on a data-carrier in the form of a card is provided when the personal data, or at least significant parts of them, can be clearly anchored on the data-carrier in the form of authenticity characteristics.

The object of the present invention is to provide an improved data-carrier, in the form of a card, in which greater security against falsification is made possible but which can still be produced by a relatively simple production technique..

J

Embodiments of the invention in particular allow the application of personal data in the form of a watermark in plastic data-carriers, and allow the three characteristic security requirements mentioned above to be fulfilled.

According to a first aspect of the present invention, there is provided a data-carrier in the form of a card I4 U 00904.TGCO25.LET.68005.spe.5 Ii i -L I -6comprising layers of plastics material with characteristics in the form of patterns or symbols, the light dark contrast of which is different when viewed by means of reflected light and transmitted light respectively, characterised in that the data-carrier bears information, comprising said patterns or symbols, which is applied by means of a laser beam to one or more of said layers, the information modifying the optical properties of the datacarrier material, the visual impression of the information being different when viewed by means of reflected light feIt from the visual impression of the information when viewed 'II by means of transmitted light.

i I The information applied by means of the laser beam is preferably in the form of a watermark, the optical impression of which is different on examination under reflected light from that on examination under transmitted light.

The watermark may immediately cover card-specific and/or personal data, for example a card serial number i and/or a picture of the card-holder and/or his or her i signature.

Following a preferred embodiment of the invention, the data-carrier according to the invention comprises i information applied by means of a laser beam which appears :I in transmitted light with one grey tone and in reflected light with two different grey tones, so that, for example, in transmitted light only the picture of the card-holder i can be recognised as a watermark, on which, in reflected light, additional information is superimposed, such as a symbol or writing, for example the signature of the holder of the card.

In a further preferred embodiment of the invention, the layers of plastics material may comprise a substrate, l. 0oo904.o4 CO25.LET.68005.spe.6 m.A -7the substrate comprising coloured plastic and being provided on one or both sides with a covering foil which may for its part also be coloured. Here the upper covering foil, through which the information is imprinted on the substrate and can again be optically identified, is transparent, while the material of the covering foil on the rear side may be transparent or somewhat opaque, i.e.

translucent.

According to a further preferred embodiment of the ,invention, the information applied by means of a laser beam is in the form of identical superimposed patterns on at 010Q least two different layers of the substrate which are in turn separated by transparent layers. In this way, 15 especially in the case of watermark images with a linear structure, tilting effects are produced on examining the card at different angles.

0000 According to a second aspect of the present invention, 0000 o00 20 there is provided a method of producing a data-carrier according to the first aspect of the present invention, which method comprises creating the information with different visual appearance on observation in direct and transmitted light by the destruction of a light-absorbing 25 or reflective pigment dispersed in one or more of said layers of plastics material with the formation of transparent reaction products by means of a laser beam.

Aluminium particles which are dispersed in polyvinyl chloride as the plastics material of said layer or layers can be used to advantage as the pigment which, under the action of the laser beam, gives transparent reaction products. The aluminium particles are to advantage dispersed in the form of extremely fine aluminium flakes and impart to the data-carrying card a metallic appearance in those areas in which the aluminium is not destroyed or removed through the action of the laser beam. When coloured covering or substrate foils are used further S 00904TGCO25.LET.68005.spe,7 T 0 optical effects can be obtained, for example a plastic identity card with a golden appearance.

In the procedure preferred according to the invention, I 5 a polyvinyl chloride foil filled with aluminium particles is used as the plastics material of said layer or layers, which can alternatively be called a substrate, this being I heated under the action of the laser beam used for the application of the information, with the result that the chain molecules of the polyvinyl chloride decompose with the release of chloride, which reacts with the metallic aluminium according to the following equation: Al 3RC1 AIC1 3 3R' R representing the organic radical of the polyvinyl chloride chain molecules and R' the residue of them after I the splitting-off of the chlorine atoms. While the aluminium in the areas not covered by the laser beam is I 20 impermeable to light, i.e. reflects light, the aluminium chloride produced in the reaction mentioned above is S' colourless, the result being that the layer treated in this way with a laser beam becomes transparent in the areas acted on by the laser beam, whereby the "watermark effect" refer- 4 NO 900904TGC025.LET,68005.spe,7 1

I

red to above is obtained. While, in fact, the foil, on account of the aluminium particles, is impermeable to light at points not thermally treated, the foil at the points acted on by the laser beam appears transparent on account of the optical behaviour of the reaction product.

With appropriately fine metering of the local heatingwhich is immediately possible with a regulated laser beam recorder the chamical reaction mentioned above can be controlled so that there is only a partial conversion of the aluminium particles. In this case it is possible to produce in the interior of the identity card a pattern which, on observation by transmitted light, appears in several shades of grey, and is thus comparable with the watermark of banknotes.

It is possible in particular, by regulating the intensity of the laser beam to apply by way of an inverse grey shade table a a photograph or other image to the data-carrier card in the form o of a watermark. In this case the transparency of the substrate 000 0 material increases on account of the chemical process mentioned 0+ o o above, and when all aluminium particles have been transformed o0 into the colourless aluminium chloride reaches the maximum transparency value, which can be adjusted within specific limits on the basis of other foil properties or the special construct- 0 4 9 ion of the card.

:4 In the case of higher energies of the laser-beam recorder a further effect is superimposed on this "transparency effect" which is described basically in German Offenlegungsschrift 48 736 and according to which the substrate material undergoes a change (change in colour, change in the mechanical S[ strength, increased resistance to chemical agents) at the points at which it is locally heated by the laser beam. It has been found that these processes or chemical reactions do not occur in a pure plastic substrate material such as polyvinyl chloride or occur only at extremely high powers of the laser beam, but then explosively and hence uncontrollably. It has now been found that when indestructible pigment particles, for example extremely or ctlfbon blac RAL, ~fine sootAparticles, are added to the substrate material, namely A/T V 0* -9polyvinyl chloride, the processes or chemical reactions in question already take place at much lower powers of the laser beam. Depending on the concentration of these indestructible particles, these processes can be deliberately initiated at lower or higher laser powers.

In this case the indestructible pigment particles, such as soot particles, absorb the irradiated energy much more strongly than the undoped substrate material and thus act as nuclei or catalysts of the process mentioned above. On account of their small dimensions the individual pigment particles are invisible to the human eye and, on account of the low concentration of them needed, have only a quite inconsiderable influence on the transparency of the substrate material. Similar, even if less pronounced, effects can be obtained by the addition of softeners to the substrate material.

In addition, the inscription of the information by means S of the laser beam may be deliberately influenced by an appropriate metering of the irradiated power, so that, for example, various shades of grey can be produced.

040w It is possible, according to the invention, in order to obtain special effects and thus to improve security against falsification of the data-carrier claimed also to disperse in the substrate material,in addition to the destructible, transf, parent reaction product or products, also indestructible pigment particles such as extremely fine soot particles which promote a change in the colour of the substrate material under the action of the laser beam. In this case the destructible and indestructible pigment particles may be dispersed in the same and/or different substrate layers in order in this way to produce further watermark effects which can hardly be falsified.

The invention will be described in greater detail below with reference to the attached drawings. In the drawings: Fig. 1 shows an enlarged partial sectional, view of one embodiment of the data-carrying card according to the invention, Fig. 2 also shows an enlarged partial sectional view of a further embodiment of the data-carrying card according to the invention, Fig. 3 shows the curves illustrating the dependence of the transparency of the substrate material on the intensity of the laser beam used, and Fig. 4 and 5 show enlarged partial sectional views of further embodiments of the data-carrying card according to the invention.

o0 0 ocro o As can be seen from Fig. 1, the data-carrier in the form o o ou ~of a card comprises a substrate 1, for example a polyvinyl chloride foil into which fine aluminium particles 2 are intro- °o duced uniformly distributed over the entire volume during the o o preparation process. In this way the foil, when viewed in direct light appears silvery and metallically shiny and on viewing in transmitted light completely dark. Further metallically 00 shiny appearances of different colours can be produced by the 0 00 o0 addition of suitable dyes.

o0o1 In the case of the embodiment of the data-carrier card according to the invention shown in Fig. 2, the substrate 1 with the aluminium particles 2 in it is enclosed by a trans- 0parent covering foil 3 on the front to protect information 0 applied by printing techniques and a rear covering foil 4 which may be transparent or opaque, for example filled with a white pigment such a titanium dioxide.

Under the action of the laser beam the aluminium particles 2 shown in Figs. 1 and 2 are subjected to a reaction with the chlorine atoms spilt off from the polyvinyl chloride, with the formation of aluminium chloride according to the equation mentioned earlier, through which the transparency of the 1.

-11 substrate material in transmitted light is increased at these points, as has been explained earlier.

The characteristic property of the substrate on which the present invention is based, this substrate containing lightabsorbing and/or reflecting pigment which can be destroyed by means of a laser beam with the formation of opaque reaction products will be explained in greater detail by means of Fig. 3. Fig. 3 comprises blackening curves which, depending on the concentration of impurities present are located at higher (curve B) or lower (curve C) intensity of the radiation power.

The increase in blackening corresponds in transmitted light to a reduction in transparency. Curve A illustrates the behaviour of the substrate material used according to the invention under Sno the action of the laser beam. In this case the transparency of the material increases with increasing intensity of the laser a beam, since, in accordance with the equation referred to above, the aluminium particles are transformed into transparent aluminium chloride. At higher radiation powers of the laser used the o oo aluminium particles, similarly to the soot particles mentioned above, act as nuclei for the blackening process. Through this, at higher radiation powers with an increase in the colouriing (blackening) of the substrate there is at the same time a decreae 0 o in transparency, a circumstance which is represented by curve D in Fig-. 3. As this curve D, in which there is a superimposition 0 5 of the curves A and B, shows, in the case of an appropriately doped substrate material the transparency at first increases with the increase in the irradiated energy on account of the chemical *4 reaction of the aluminium particles, and then decreases with a simultaneous increase in the blackening of the substrate material.

Through this it is found that a required transparency grey value of 33 can be represented in each case by two different, but no longer freely selectable grey shades 34 and 35 for observation in direct light. In this way it is possible to produce an image-like representation in one area of the card which depending on the manner of viewing gives different images in -12transmitted light and direct light which stand ih a clear mathematical relationship through the blackening and transparency curves. Pairs of image-like representations which cannot berepresented with other means can be produced through this correlation which is given quite specifically by the recipe of the substrate material. Hence, according to the invention, through an appropriate selection of the ratio of destructible to indestructible pigment (aluminium particles or soot particles) and the particle size and shape of them as well as their chemical composition different blackening and transparency profiles are brought about and thus various watermarks with different grey tones are produced.

In a simple embodiment of the invention, for example, lines or patterns in two different tones of grey which appear only on viewing in direct light can be shown in an area which appears in a grey tone in transmitted light. It is in addition S possible, for example on an image representation such as a o photograph of the holder of the card to represent a symbol, for instance a logo or the like, or lettering, for example the signature of the card-holder, these additional characteristics being clearly recognizable in direct light, but not in trans- 0 0" mitted light.

0 .4 8 8 Further variations of these effects can be obtained by the combination of different foils and substrate layers.

If, for example as i the embodiment of the invention shown in Fig. 4, a transparent foil 43 is provided on the rear side of the data-bearing card, the watermarks disappears almost completely when viewed in direct light, while when a white foil 43, for example filled with titanium dioxide, the watermark appears fainter in transmitted light, but remains distinctly discernible in direct light.

In the case of the embodiment shown in Fig. 4 the databearing card comprises four foils, of which the covering foil is transparent the first inset foil 41 is doped with II I L -13aluminium particles, the second inset foil 42 is' again transparent and the foil 43 on the rear side is tightly filled with titanium dioxide, i.e. it is white and has a high degree of opacity. In the case of this card construction the image or pattern produced in the foil containing the aluminium particles, on the lateral action of light through the cut edges of the card shines from the interior over the transparent inner foil.

A further preferred embodiment of the data-bearing card according to the invention is shown in Fig. 5. This datacarrier, which is composed of five layers, comprises in each case a transparent covering foil on the front side and the rear side of the card (50 and 51 respectively), as well as a transparent intermediate foil 52 between the two foils 53 and 54 containing aluminium particles. With a cerd construction S of this kind, especially with watermarks of linear structure, o0 tilting effects occur when the card is viewed from different S angles.

oo In addition to the fact that data-carrying cards according to the invention can be created with "watermarks" specific to the card or to a person, the present invention makes possible i a series of further important advantages in comparison with the known watermarks of securities.

The watermark is applied to the finished identity card blank. This firstly simplifies the entire production flow and secondly renders unnecessary troublesome storage with protection against unauthorized interference and secure transport of the blanks on which authenticity Scharacteristics already appear.

S.

The watermark can be produced in the same operation as the other data which appear on the identity card.

The flexibility of the laser inscribers available -14permits an alteration of the watermark from one identity card to another, so that itbecomes possible to produce each identity card in the form of an unicum, for example by using a serial number in the form of a watermark (cardspecific data).

The production of the watermark at the same time as the inscription of the other personal data, associated with the flexibility of the laser inscriber makes possible the production of a personal watermark, for example in the form of the signature or a photograph of the holder of the card and thus the unfalsifiable incorporation of personal data into the authenticity characteristic.

In this way it is possible in a very simple and neat manner to solve the problem referred to above and to provide a O data-carrier in the form of a card the authenticity of which can be clearly recognized even by the "man in the street".

0 00 0o auo o i 0 0a 6 oa 4 44 o 0 a

Claims (15)

1. 2. Data-carrier as in claim 1, characterised in that the i information applied by means of the laser beam comprises i card-and/or person-specific data.
2. 3. Data-carrier as in claim 1 or characterised in that the information applied by means of the laser beam is presented in the form of a watermark. ii 4. Data-carrier as in claim 3, characterised in that the information presented in the form of a watermark bears *I additional information producing different tones of grey when viewed by means of reflected light. Data-carrier as in claim 4, characterised in that the information applied by means of the laser beam appears in one grey tone when viewed by means of transmitted light and in two different grey tones when viewed by means of reflected light.
3. 6. Data-carrier as in claim 4 or 5, characterised in that the information presented in the form of a watermark comprises an image representation visible only when viewed kI 900904.TGC025.LET.68005.spe,15 I I way impossible to control. Moreover, these methods are not suitable for visual identification of authenticity. R RA"L,\ U 900904.TGC025.LET.68005.pe.4 j 16 by means of transmitted light which bears as additional information a symbol or lettering which is clearly recognizable when viewed by means of transmitted light, but not when viewed by means of reflected light.
4. 7. Data-carrier as claimed in any one of the foregoing claims, characterised in that at least one of first and second layers of said layers of plastics material is coloured, said first layer being covered on a first face thereof by said second layer, the information being applied to said first through the second layer by means of the laser beam.
5. 8. Data-carrier as in claim 7, characterised in that the second layer is transparent and the first layer is covered on the second face thereof by a third layer of material. 4o4o 9. Data-carrier as in claim 8, wherein said third layer is transparent. o
6. 10. Data-carrier as in claim 8 wherein said third layer is opaque.
7. 11. Data-carrier as in any one of the foregoing claims, characterized in that the information applied by means of the laser beam is presented in the form of identical superimposed patterns on at least two different layers of the data-carrier separated by a transparent layer.
8. 12. Method of preparing a data-carrier according to any one of the preceding claims, characterised in that the information is applied by the destruction of a light- absorbing and/or light-reflecting pigment, which pigment is dispersed in one or more layers of the data-carrier, with the formation of transparent reaction products in the one or more layers, by means of the laser beam. U \900904.TGC025.LET,68005.spe,16 I fT According to a first aspect of the present invention, there is provided a data-carrier in the form of a card i00904,TGCO25.LET.68005.spe,5 -17-
9. 13. Method as in claim 12, characterized in that aluminium particles are used as the pigment producing transparent reaction products and polyvinyl chloride is used as the material of the one or more layers.
10. 14. Method as in claim 12, characterised in that the one or more layers contains, in addition to the destructible pigment which gives transparent reaction products, indestructible pigment particles which promote said destruction by means of the laser beam.
11. 15. Method as in claim 14, characterized in that extremely fine carbon black particles are dispersed as indestructible pigment particles in the one or more layers.
12. 16. Method as in claim 14 or 15, characterised in that the indestructible pigment particles are dispersed in the i material of the one or more layers in a particle size and quantity which do not adversely affect the transparency of the one or more layers.
13. 17. Method as in any one of claims 14 to 16, characterised in that the destructible and indestructible pigment particles are dispersed in the same and/or different layers 4" 25 of the one or more layers.
14. 18. A data-carrier substantially as hereinbefore described with reference to the drawings. I TGC25LET68005. e I 4 90090 4, TGC025.LET.68005.spe,17 1I In a further preferred embodiment of the invention, the layers of plastics material may comprise a substrate, I~cupnn~ '-~iuarrrc-~p-h~u U L :i i i Y-L.iYd~lii"l'i~C~~~; 18
15. 19. A method of preparing a data-carrier substantially as hereinbefore described with reference to the drawings. DATED this 10th day of August, 1990. MAURER ELECTRONICS GMBH and LEIGH-MARDON PTY. LIMITED By their Patent Attorneys DAVIES COLLISON I I H\I)I i iE 600 pe1 g k 900904,TGC25.LET.68005.spe ,18 i I i