MXPA00012118A - Irradiated images described by electrical contact - Google Patents

Abstract

A device generating images described by contact (fig. 1, element 101), in which the contact itself closes an open circuit to generate radiation in a pattern in register with the contact. The resulting irradiated image corresponds directly to the contact pattern energizing the radiation. In a preferred embodiment enabled by an electroluminescent system (fig. 1, element 100) without a back electrode, a fingerprint is disposed to close the open circuit by making contact and thereby serving as a"temporary"back electrode. The electroluminescent then energizes in a pattern in register with the contact (fig. 1) (i.e. the fingerprint) to emit a high-resolution image of visible light with high fidelity to the contact (figs. 5a and 5b). This visible light image may then be directed onto a photosensitive array standard in the art suitable for pixelation and conversion into an electrical signal representative of the image. This signal is available for computerized storage, analysis, processing and comparison.

Description

IRRADIATED IMAGES REPRESENTED BY ELECTRICAL CONTACT FIELD OF THE INVENTION This invention relates, in general, to devices that generate contact images (such as fingerprints), and more specifically to a device that causes a pattern of the contact itself to selectively close an open circuit, wherein the circuit closure supplies power to an irradiated image that is in direct correspondence with the contact pattern.

BACKGROUND OF THE INVENTION Devices for capturing images described by contact on a surface are known in the art. A primary, though by no means exclusive, application for those imaging devices is in the area of fingerprinting, whether for security, forensic studies or other purposes. Other applications include the analysis of surface texture for classification or analysis purposes, or record contact for archival purposes, or possibly for mechanical duplication. All the preceding applications involve moving the image described by contact, to a reproducible record of the image. For example, in the fingerprinting application, a traditional system is to "apply ink" to the fingers and roll them on the surface of a paper or a card. Of course, without further exploration of the results, those systems lack the ability to generate signals usable by the computer, representative of the images. Without the storage and analysis capabilities of a computer, cataloging and comparing those fingerprint images is a time-consuming and unpredictable task. The latest devices project light on the fingerprint, through a prism. The reflected image can be captured on a photosensitive film, or received on a photosensitive array. In the latter case, the image can be converted to image elements and stored as an analog or digital signal representative of the image. These signals are now available for further processing by computers. The references of the prior art cited in this description demonstrate that fingerprinting is a popular application of the "reflected image" technique. It is also known that the same technique of "reflected image" is used in the exploration of images on paper or other textile products, in scanners and photocopiers. The disadvantage of all devices that employ a technique for recording images, based on the "reflected image", is that by definition they need an independent light source and an optical structure (such as a prism) to create a reflected image. The same is true with respect to "reflected image" techniques that use radiation outside the visible light band of the electromagnetic spectrum. By definition, an independent radiation source and a reflection / diffraction structure is still required. Other current art devices, which generate contact images, use proximity sensors to detect changes in characteristics, such as capacitance or magnetic flux. The disadvantages of these devices are that (1) they may not be reliable, and (2) can be expensive. They are not reliable since, when detecting variations, for example, in the capacitance, there is no way to know if the change in capacitance is caused by the contact or by some other isolated source. In addition, an expense must be incurred in those devices, by creating a set of sensor circuits, which have fidelity and resolution comparable to the ability to capture and separate the reflected radiation, such as visible light. Therefore, there is a need in the art for a device that generates images described by contact, wherein the contact is the main source of energy for the image itself. In this way, the additional structure required in the techniques of "reflected image" would be ignored. Furthermore, it would be very advantageous if that inventive device were not based on proximity sensors to detect contact. The inventive device would then have an improved prediction capability regarding operation, without requiring complex 0-sensor circuits, to interpret the contact.

SUMMARY OF THE INVENTION These and other objects, features and advantages < 5 techniques are achieved by an invention that generates images described by contact, in which the contact itself closes an open circuit to generate radiation with a pattern that is in correspondence with the contact. In this form, an irradiated image results that corresponds directly to the contact pattern that supplies energy to the radiation. In this way the invention has immediate (though not exclusive) application to techniques for fingerprinting. In a preferred embodiment made possible by an electroluminescent system without a back electrode, a fingerprint is placed to close an open circuit when making contact and therefore serves as a "temporary" back electrode. The electroluminescent system is charged with energy then with a pattern that is in correspondence with the contact (ie the fingerprint) to emit a high resolution visible light image, with high fidelity with respect to the contact. This image can then be directed on a photosensitive array standard in the art, suitable for the formation of imaging elements and the conversion into an electrical signal representative of the image. This signal is available for computerized storage, analysis, processing and comparison. Advantageously, the electroluminescent system that makes a preferred embodiment possible is a low-cost stencilled polymeric film ("PTF") lamp, which can be supplied with alternating current, low voltage electricity (it is say 20 to 30 volts of alternating current) at frequencies that are in the range of 400 Hz to 2 KHz. Such a source of electrical energy is well known in the art for being available in inverters of low voltage integrated circuits (i.e. 3 to 5 volts direct current). The electroluminescent system will then be very safe for those who touch it, by virtue of the very low levels of current generated by that electrical system. Of course, it will be appreciated that the invention is in no way limited to fingerprinting applications. In accordance with the invention, any form of electrically conductive contact will describe an irradiated image. In this way, images of the surface textures of many objects, animated or inanimate, can be formed with the invention. In addition, the invention is not limited to contact that generates visible light through electroluminescence. Although the preferred embodiment described is highly advantageous, the invention, in its broadest form, encompasses the generation of irradiated images described by contact, wherein the contact itself closes an open circuit to activate the radiation in correspondence with the contact. In this way, the generation of any radiation in the electromagnetic spectrum falls within the scope of the invention. For example, an infrared image could be generated by an open circuit where the heat is emitted with a pattern that is in correspondence with the selective closure of the circuit by contact. Clearly, still further fidelity and resolution of the images described by contact may be available through the selection of the wavelength of the radiation generated by the invention, depending on whether it is compatible with the device receiving and interpreting the irradiated image. . Similarly, the use of electroluminescence, in the preferred embodiment, should not be considered as • limiting. Clearly, the use of the contact to form the back electrode of an electroluminescent lamp is a highly advantageous activation of the radiation in correspondence with the contact. However, the invention is of a broad concept because it uses the contact itself to close and open the circuit in order to activate the radiation in • correspondence with the contact. In this way it will be appreciated that the invention is made possible through any open circuit capable of generating radiation that is in correspondence with the selective closure of the circuit by means of a contact pattern. Therefore, a technical advantage of the present invention is to generate an irradiated image corresponding to the contact, causing the contact to close an open circuit, thus obviating the need for an apparatus additional, such as an independent radiation source and a reflection / diffraction structure, to enable a "reflected image". A further technical advantage of the invention is to eliminate the lack of predictability and complexity Potential in the manufacture of devices that use a "proximity sensor" structure to generate a contact image. A still further technical advantage of the invention is that it can be reliably and economically made possible in a stencilled PTF electroluminescent lamp, wherein the contact forms the back electrode of the lamp. The visible light in a pattern in correspondence with the contact, can then radiate towards a photosensitive array. This arrangement in turn can form image elements of said image and prepare a signal usable by a computer, corresponding to the image. The foregoing has broadly outlined the features and technical advantages of the present invention, so that the following detailed description of the invention can be better understood. Further features and advantages of the invention will be described below, which form the subject of the claims of the invention. Those skilled in the art should appreciate that the specific design and embodiment described may be readily utilized as a basis for modifying or designing other structures to accomplish the same purposes of the present invention. Those skilled in the art should also understand that these equivalent structures do not depart from the spirit and scope of the invention as presented in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: Figure 1 is a cross-sectional view of an embodiment preferred of the present invention; Figure IA is a cross-sectional view of an alternative embodiment of the present invention; Figure 2 is an enlarged view of the contact as shown in Figures IA and IB. Figure 3 is a cutaway view of the embodiment of the invention illustrated in Figure 1. Figure 4 depicts the invention in operation; and Figures 5A and 5B are real thumbprint images of a thumb, obtained using the preferred embodiment.

DETAILED DESCRIPTION OF THE INVENTION As described in a summarized way above, the present invention focuses on an apparatus capable of emitting radiation corresponding to the zones of contact on a surface, where the contact closes ^ _ physically an open electrical circuit, and where the closure of the circuit activates the radiation in a pattern in correspondence with the contact, with a high degree of fidelity and resolution. This apparatus is particularly advantageous for generating fingerprints, fingerprints of the palm of the hand, footprints or other images of the skin, in where the skin is electrically conductive. One modality Preferred will be analyzed with reference to the generation of a visible light image of the fingerprint of a human thumb, although as already discussed, the invention is not limited in this respect. Images of other skin anatomical regions of human beings, as well as other living forms, can be generated by the invention, as long as the skin whose contact is described by ^ the image, be electrically conductive. In addition, the invention is not limited to the generation of images of anatomical contact. It will be appreciated that the other embodiments of the invention can generate irradiated images described by the contact on a contact surface, by any electrically conductive zone where a previously open circuit is now closed by contact. By Accordingly, the images corresponding, for example, to metallic surface textures, or "watermarks" on fabrics, textiles or papers, electrically conductive, can be generated by the invention, with the effect of equivalent rating. The preferred embodiment will be described further with reference to the generation of visible light using an open electroluminescent system, closed by contacting the fingerprint of a thumb on a contact surface. However, it will be appreciated further that the invention is not limited in this respect. Consistent with the invention, the contact area can be described by the radiation in any part of the electromagnetic spectrum, and not only in the visible light band as is made possible by the preferred embodiment analyzed later. For example, the images in the infrared and ultraviolet bands are consistent with the invention, wherein the irradiated images of those emissions have useful applications. Likewise, the use of an open electroluminescent circuit 20, in a preferred embodiment, should not be considered as limiting according to the invention. Electroluminescence has useful applications in the visible light band because an open circuit can be easily and economically deployed in the form of a laminated product, wherein the contact from which the image is to be formed can form a rear electrode, thereby closing the circuit and generating light in correspondence with the contact. However, it will be appreciated that other forms of circuits will be consistent with the invention, wherein the contact closes and opens the circuit to generate the corresponding, irradiated images outside the visible light band. For example, consistent with the invention, heat could be generated in correspondence with the passage of current through a circuit closed by contact. Accordingly, circuits that generate infrared radiation in correspondence with the closing contact of the circuit will be permitted by the invention. In this way, by selecting several radiation generating components, in the open circuit to be closed by the contact, other types of circuits will make the invention possible. Now focusing on Figure 1, a general arrangement of the preferred embodiment includes a human thumb 10 which contacts its fingerprint, on a contact surface 101 on the electroluminescent system 100. The thumb 10 also concurrently makes electrical contact with the finger. contact plate 120, and the contact plate 120 is electrically isolated from the electroluminescent system 100. With further reference to Figure 1, the electroluminescent system 100 comprises the substrate 105 on which the translucent electrode layer 104 is deposited. Preferred embodiment, the substrate 105 may be of any suitable material that allows the passage of visible light, such as polyester, polycarbonate, vinyl or elastomer. In a preferred embodiment, the active ingredient added in the translucent electrode layer 104 is Tin and Indian Oxide ("ITO"), although any other addition material, based on transparent metal oxide, with equivalent functionality, can be used. in the art, such as for example Tantalum Oxide. In another embodiment (not illustrated) the substrate 105 and the translucent layer 104 can be combined using a sheet of polyester with ITO, with prior cathodic sputtering. The translucent electrode layer 104 also includes the bus bar 106 connected to the electrical power source 110. Although shown in section. In Figure 1, it will be appreciated that the bus bar 106 is continuous within the translucent electrode layer 104 in order to supply energy to the flat area of the layer. In a preferred embodiment, the bus bar 106 is stencilled onto a substrate 105, using a thick film of silver polymeric ink (PTF), prior to stenciling, of the translucent electrode layer, on the substrate 105.

However, it will be appreciated that the busbar 106 is not limited in this way, and may also be, for example, a thin strip of copper adhered to the substrate 105 before depositing the translucent electrode layer 104. Of course, if the polyester sheet with ITO, with prior cathodic sputtering , is used to combine the substrate 105 and the translucent electrode layer 104 (not shown), then the bus bar 106 can be removed. Continuing with the reference to Figure 1, the contact surface 101 is on top of the envelope layer 107. The envelope layer is an electrically conductive layer that protects the electroluminescent system 100. Advantageously, the envelope layer 107 is a hard wear-resistant material, in order to give the contact surface 101 long life. Examples of suitable materials for the wrapping layer 107 when the invention is practiced according to screen printing techniques, as described further below, are epoxies, polyurethanes, acrylics and other hard materials, resistant to wear, Similar. The envelope layer 107 and the translucent electrode layer 104 are separated by the dielectric layer 102 and the luminescent layer 103. In a preferred embodiment the sequence of layers is as shown in Figure 1, wherein the luminescent layer 103 is closer to the substrate 105 than the dielectric layer 102. The invention would be made even more possible if the luminescent layer 103 and the dielectric layer 102 were inverted. The light irradiated from the luminescent layer 103 would then have to pass through the dielectric layer 102 to reach the substrate 105, however, possibly with the disadvantageous effects such as loss of energy, diffusion or diffraction. Accordingly, a preferred embodiment arranges the layers as shown in Figure 1. In a preferred embodiment the active ingredient in the dielectric layer 102 is Barium Titanate and in the luminescent layer 103 it is encapsulated phosphorus. The inks added with these ingredients are applied as stencil stamping, on top of each other, before the wrapping layer 107 is stamped to seal the system. Note that to obtain optimum results, the luminescent layer 103 should be deposited in an extremely uniform manner to generate a predictable and constant light emission, by contact at any point on the contact surface 101. Figure IA represents an alternative embodiment in the that the envelope layer 107 of FIG. 1 is omitted and its function is replaced by a wear resistant hard dielectric layer 102A. In FIG. IA, therefore, the contact surface 101A is on the dielectric layer 102A. The dielectric layer 102A in FIG. ^^ advantageously composed of Barium Titanate added to an epoxy layer stamped with stencil, the epoxy is selected as the binder to have wear resistance and environmental resistance. The advantage of the modality according to figure A, is, of course, that it has fewer components and therefore is more economic. The disadvantage compared to the modality of Fig. 1, however, is that as the dielectric layer 102A wears with use, the layer itself deteriorates. Finally, as wear continues, it can directly affect the luminescent fidelity of the device inventive in describing the contact on the contact surface 101A. To prepare and prolong the life of the system represented in Figure IA, it is, therefore, highly advantageous catalytic reticulation of the system, using chemical treatment or radiation techniques ultraviolet, known in the art. Returning now to Figure 1, it will be noted that the electroluminescent system 100 is incomplete since it lacks a subsequent electrode. In addition, when the electric power supply 110 is connected between the busbar 106 and the contact plate 120 as shown in Fig. 1, results in an open circuit, extending from the contact surface 101, through the electroluminescent system 100, and around the contact plate 120 to through the electric power supply 110. In accordance with the present invention, and as shown in Figure 1, the thumb 10 completes the open circuit, concurrently touching the contact plate 120 and making contact through the fingerprint finger digital, with the contact surface 101. It will be appreciated that the contact plate 120 is only a choice to enable electrical contact with the thumb 10, and that other methods (such as that of a wire attached by an electrode ) would have an equivalent enabling effect. However, it is of particular inventive significance that the thumb 10 makes contact, with its fingerprint, on the contact surface 101. As shown in enlarged form in Figure 2, the thumb 10 makes selective contact zones C in a pattern described by ridges 201 touching contact surface 101, while valleys 202 remain clear. The open circuit described above with respect to Figure 1 is thus selectively closed with a pattern that is in correspondence with the contact areas C. This circuit in turn causes the electroluminescent system 100 to be activated with a pattern that is in correspondence with the contact areas C, in such a way that the luminescent layer irradiates a visible light image with high fidelity and resolution in the areas of the contact C. In the embodiment of the invention shown in figure 1, this irradiated image is projected downwards and through the substrate 105. Figure 1 also shows a photosensitive array 150 immediately below the substrate 105. The photosensitive array 150 can form image elements of the irradiated image described by the contact areas C, in Figure 2, to produce electrical signals representative of the image. These signals can be further processed according to the application for the inventive device. Referring again to the analysis of the beginning of this section, it will be noted therefore that the thumb 10 of Figure 1 can be replaced by other electrically conductive structures whose surface texture can be described by an image irradiated through contact with the surface 101. In addition, although Figure 1 has described an electroluminescent system that generates a visible light image, describing contact areas C on the contact surface 101, a broader aspect of the invention is that irradiated images are generated upon completion selectively an open electrical circuit that is in correspondence with the contact. Thus, as described above, other forms of radiation generated through the selective closure of other types of open circuit fall within the scope of the invention. Figure 3 illustrates the invention in a sectional view. As suggested above, a preferred embodiment of the invention deploys the electroluminescent system 100 (as shown in Figure 1) by successively stamped layers in accordance with the laminated product described. Advantageously, stencil printing techniques, such as those described and provided in greater detail in the co-pending US patent application, commonly assigned, "ELECTROLUMINISCENT SYSTEM IN MONOLITHIC STRUCTURE" No. of "Series 08 / 656,435, filed on May 30, 1996, the description of which is fully incorporated herein by reference, will be used to make the present invention possible, specifically, the materials, quantities, and techniques described in the co-pending application to which it was made reference above, which use a vinyl resin carrier in the form of a gel, will allow a hard, wear resistant, electroluminescent laminate product suitable for the thumb fingerprinting application described above. Figure 4 illustrates the irradiated image R of the invention described by the fingerprint contact of the thumb 10 on the contact surface 101. In Figure 4, the image R is passed through a photosensitive array 150 such as it was described above with reference to Figure 1. Figures 5A and 5B are representations of fingerprint images of a thumb, irradiated according to the preferred embodiment described herein, as captured through a digital camera . The high degree of fidelity and resolution will be appreciated. With reference to the preferred embodiment, the adjustment, specific to the application, of the thickness of the electroluminescent system layer, may be necessary, in combination with the corresponding adjustment of the parameters of the electric power supply source and the concentrations of the electroluminescent system. addition material, in order to maximize fidelity, contrast and resolution. For example, in the fingerprint generator of the thumb, described herein, using a detailed electroluminescent system in the co-pending North American Application, referred to above. "ELECTROLUMINISCENT SYSTEM IN MONOLITHIC STRUCTURE", the electric power supply 110 in Figure 1 should generate at least 20 volts of alternating current at approximately 1.5 kHz. However, note that a voltage above 50 volts of alternating current can generate an electrical sensation to an adult human user, although it does not harm the current levels generated by the device. The power supply requirements will also vary with the physical size of the irradiated image that is expected to be described by contact. For example, in the arrangement described above, experimentation has shown that 20 volts of alternating current at 1.5 kHz generate a satisfactory image for the fingerprint of the thumb or another human finger, my "enter" that 30 volts of alternating current at 2 kHz are necessary to obtain an image of the palm prints of the hand, satisfactory. Note that from the point of view of the applications, the inverter modules based on integrated microcircuits convert the low direct current voltages (from 3 volts to 5 volts) into voltages and alternating current frequencies, suggested, described. The low currents generated by these modules are ideal for electroluminescent PTF systems and are very safe for human use. Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations may be made, without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (20)

NOVELTY OF THE INVENTION Having described the foregoing invention, it is i considers as a novelty, and therefore, what is contained in the following is claimed as property: CLAIMS

1. A method to generate an image that describes 10 the selective contact, characterized in that it comprises: (a) I deploying an open electrical circuit, through a receiving surface, the circuit includes a radiation source that can be activated with the closing of the electrical circuit; (b) touch the receiving surface with a 15 contact surface, wherein the contact is effective to selectively close the electrical circuit in a pattern that is in correspondence with areas of electrical communication between the contact surface and the receiving surface; and (c) in response to the selective closure of the electrical circuit, 20 generate an image that corresponds to the areas of electrical communication, the image includes radiation excited in the pattern.

2. A method for generating an image describing the selective contact, characterized in that it comprises: (a) In order to provide a laminated product, the laminated product includes an outer receiving surface, a luminescent layer, a dielectric layer and a translucent electrode layer, the receiving surface on the laminated product is separated from the translucent electrode layer, by the dielectric layer and the luminescent layer; (b) connecting a source of electrical energy to the translucent electrode layer; (c) touching the receiving surface with a contact surface, wherein the contact is effective to selectively couple the source of electrical energy through the contact surface and through the laminate, in a pattern that is in correspondence with the zones of contact between the contact surface and the receiving surface; and (d) in response to the selective coupling, supplying energy to the luminescent layer in order to generate light in the pattern.

3. The method according to claim 2, characterized in that the contact surface is topographically non-uniform.

4. The method according to claim 2, characterized in that the laminated product is a laminated polymeric film laminated product using a stencil process.

The method according to claim 4, characterized in that the rolled product is developed by depositing successive layers, suspended in a vinyl resin carrier in the form of a gel.

6. The apparatus for generating an electroluminescent image that describes the contact on an electroluminescent system by means of an independent contact surface, characterized in that it comprises: a laminated product, the laminated product has an outer receiving surface, the laminated product includes a luminescent layer, dielectric layer and a translucent electrode layer, the laminate is further positioned such that the receiving surface is separated from the translucent electrode layer, by the dielectric layer and the luminescent layer; a means for concurrently connecting a source of electrical energy to the translucent electrode and to the contact surface; and means for selectively connecting the source of electrical energy through the laminated product in a pattern that is in correspondence with contact zones between the contact surface and the receiving surface, wherein, in response to selective coupling, the luminescent layer generates light with that pattern.

The apparatus according to claim 6, characterized in that the contact surface is topographically non-uniform.

The apparatus according to claim 6, characterized in that the contact surface is a fingerprint.

9. The apparatus according to claim 6, characterized in that the laminated product is a laminated product of polymeric thick film.

10. The apparatus according to claim 6, characterized in that the translucent electrode, the selected dielectric and luminescent layers are deposited using a screen printing process.

The apparatus according to claim 6, characterized in that the translucent electrode, the selected dielectric and luminescent layers, adjoining, are suspended in a unitary gel vehicle, before the deposition thereof.

12. The apparatus according to claim 6, characterized in that the means for connecting the electric power source to the translucent electrode layer includes a bus bar layer in the rolled product, the rolled product is further positioned in such a way that the translucent electrode layer separates the busbar layer from the receiving surface.

The apparatus according to claim 6, characterized in that the means for connecting the source of electrical energy to the contact surface includes an electrode deposited in physical proximity to the receiving surface, such that the contact surface can touch the electrode concurrently when making contact with the receiving surface.

The apparatus according to claim 6, characterized in that the translucent electrode layer includes indium oxide and titanium as an active ingredient.

15. The apparatus according to claim 6, characterized in that the dielectric layer includes Barium titanate as an active ingredient.

16. The apparatus according to claim 6, characterized in that the luminescent layer includes encapsulated phosphorus as an active ingredient.

17. The apparatus for generating an electroluminescent image that describes the contact on an electroluminescent system, by means of a fingerprint, characterized in that it comprises: a laminated product of polymeric thick film, the laminated product has an outer receiving surface, the laminate comprises: a layer dielectric that includes Barium titanate as an active ingredient; a luminescent layer that includes encapsulated phosphorus as an active ingredient; a translucent electrode layer including Indium and Tin oxide as an active ingredient; and, a bus bar layer; the laminate is further positioned such that (1) the receiving surface is separated from the translucent electrode layer, the dielectric layer and the luminescent layer, and (2) the translucent electrode layer separates the bus bar layer from the receiving surface; a means for concurrently connecting a source of electrical energy to the busbar and the fingerprint, the means for connecting the fingerprint includes an electrode placed in physical proximity to the receiving surface, such that the fingerprint can touch the electrode concurrently when making contact with the receiving surface; and means for selectively connecting the source of electrical energy through the laminate, in a pattern that is in correspondence with contact zones between the fingerprint and the receiving surface, wherein, in response to the selective coupling, the luminescent layer generates light in that pattern.

18. The apparatus according to claim 17, characterized in that the translucent electrode, selected dielectric and luminescent layers are deposited using a screen printing process.

19. The apparatus according to claim 17, characterized in that the translucent electrode, adjacent dielectric and luminescent layers, are suspended in a unitary gel vehicle prior to deposition thereof.

20. The apparatus according to claim 17, characterized in that the source of electric power generates between 20 volts and 40 volts of alternating current, at a frequency that is in the range of 1.5 kHz and 2 kHz.