MX2008008980A - Proximity sensor with connection hole, and method for manufacturing the same - Google Patents

Abstract

The present disclosure relates to a capacitive sensor film (50) for mounting to a body, said film comprising a backing layer (2) having, on one side, a rear major surface (2a) facing, in use, the body and, on the other side, a front major surface (2b), said rear major surface (2a) bearing a guard conductor (1) and said front major surface (2b) bearing a sensor conductor (7), and at least on through-going hole (10) extending through the backing layer to enable electrical contact to be made to one of the conductors from the respectively opposite side of the film, wherein the inner wall of the through-going hole is covered, at least partly, by an electrically-insulating film (11).

Description

PROXIMITY SENSOR WITH CONNECTION HOLE AND METHOD FOR MAKING THE SAME FIELD OF THE INVENTION The present description relates to a capacitive sensor film for mounting to a body, for example to detect the presence of an external object. The present disclosure also relates to an improved method for manufacturing such capacitive sensor films. BACKGROUND OF THE INVENTION Capacitive proximity sensors have been used in various industrial applications to locate the presence of objects or materials. Various forms of capacitive proximity sensors are known and are suitable for use in different environments and applications including, for example, touch operated systems, collision avoidance systems, occupancy detection systems, and security / warning systems. In one field of application, the capacitive proximity sensors have been coupled, for example, with the rear side and / or bumper trolleys. When the vehicle is reversed a warning signal is provided when the car approaches an object in such a way that a collision can be safely avoided while still allowing the driver to position the car conveniently close to such an object. The British patent 2,400,666 describes a Ref..194710 capacitive proximity sensor comprising a substrate that carries two metal plates on their opposite major surfaces. The capacitive proximity sensor can be provided inside the bumper of a vehicle. The metal plate facing outwards is referred to as the sensor conductor while the metal plate facing the car body is called the protective conductor. The sensor conductor is printed with grid with conductive ink on the substrate while the protective conductor can be a metal strip. The protective conductor is typically larger than the sensor conductor and provides a shield between the sensor conductor and the carriage body. The change in capacitance between the sensor conductor and the ground is monitored and provides an indication of the distance between the carriage and the object. Control devices for capacitive sensors are described, for example, in GB 2,396,015 and in WO 02/19,524. GB Patent 2,374,422 addresses the problem of reducing the sensitivity of a capacitive proximity sensor to very close objects that the sensor is not required to detect. Specifically, in the case of a sensor on a vehicle bumper, GB Patent 2,374,422 addresses the problem of reducing the effect of the presence of water caused, for example, by continuous rain. In one embodiment it is suggested to provide an additional conductive plate on the main side of the substrate that carries the sensor conductor. The additional conductive plate, which can be arranged on the sensor conductor side above or below the sensor conductor or both (with respect to street level), is frequently referred to as the maximum protection conductor. In operation, an amplified protection signal is applied to the maximum protection conductor, which has the effect of making the protection appear larger. The maximum protective conductor is effective in attenuating or minimizing capacitance changes that result from dripping water running through the front of the sensor. A capacitive proximity sensor comprising a maximum protection conductor is also described in GB 2,404,443. British Patent GB 2,348,505 describes a geometry of the sensor conductor where the end regions of such a conductor may be wider than their central position. This tends to improve the sensitivity of the capacitive proximity sensor at the corners of the vehicle. British Patent 2,386,958 discloses an integral capacitive sensor for proximity detection, which is integrally molded into either the rear face or the center of the bumper of a carriage. U.S. Patent No. 5801,340 describes a capacitive sensor for detecting the pressure of an object in a detection region which has a relatively complicated construction and comprises, in the given sequence, a conductive earth plate, an insulator, a conductivity protection layer, a insulator and a conductive sensing or sensing plate followed by another insulator. US Patent No. 2002 / 0,158,582 describes a capacitive sensor for automotive applications comprising an essentially non-conductive shield, an electrically insulating film located behind the shield and having two faces each of which is at least partially coated with an electrically conductive material. The capacitive detectors discussed so far do not meet all practical requirements to a sufficient degree. The electrical contact is typically made with the conductor plates on the opposite surfaces of the substrate from both sides of the capacitive sensor device which provides for the incorporation of the sensor device in the desired location, for example within the bumper of a trolley, more complicated and adversely affects the reliability of the sensor device during its useful life. The manufacturing methods of the capacitive proximity sensors described in the prior art include, for example, grid printing or coating the conductor plates which is expensive and therefore does not meet the requirements of mass production. Other conventional capacitive proximity sensor constructions require mechanical anchoring which increases costs and is less desirable from a processing point of view. Accordingly, in some embodiments, the present disclosure provides a capacitive proximity sensor device which does not exhibit the disadvantages of state of the art devices or exhibits these to a lesser degree only. In some embodiments, the present disclosure provides a capacitive sensor device which can be contacted electrically in an easy and reliable manner. In some embodiments, the present disclosure provides a method of manufacturing capacitive proximity sensors which are improved compared to state of the art methods and meet mass production requirements. Other features and advantages of various embodiments of the present disclosure may be understood from the following detailed description. SUMMARY OF THE INVENTION The present description relates to a capacitive sensor film for mounting to a body, the film comprises a reinforcing layer having, on one side, a rear surface oriented, in use, to the body, and, on the on the other side, a front main surface, the rear main surface carries a protective conductor and the front main surface carries a sensor conductor, and at least one through hole extending through the reinforcement layer to allow electrical contact to be created with one of the conductors from the opposite side of the film, wherein the inner wall of the through hole is covered, at least partially, by an electrically insulating film. The present disclosure further relates to a method comprising (i) providing a reinforcing layer comprising a back main surface and a front main surface, (ii) applying a protective conductor to the back main surface of the backing layer, (iii) applying a sensor conductor to the front main surface of the reinforcement layer, (iv) providing one or more through holes or holes extending through the reinforcement layer in such a way that the protective conductor, the The sensor conductor and optionally the maximum protective conductor can be electrically contacted from a main surface of the laminate. The present description is also more particularly related, but not exclusively, with the use of the capacitive sensor film of the present disclosure for automotive applications. BRIEF DESCRIPTION OF THE FIGURES Fig. 1 shows a top view of the front main surface of the reinforcing layer 2 of a precursor of a capacitive sensor film 50 of an embodiment of the present disclosure. Fig. 2 shows a cross-sectional view of the precursor film of Fig. 1 along the line AA indicated in Fig. 1. Fig. 3 is a top view of the cross-sectional view of the capacitive sensor film 50 comprising two through holes 10. Fig. 4 is a top view of the capacitive sensor film of Fig. 3 further comprising an electrically insulating film 11 covering the through holes 10. Fig. 5 is a top view of the capacitive sensor film 50 of Fig. 4 comprising two additional auxiliary conductors 12, 13 electrically connected to the sensor conductor 7 and the maximum protection conductor 5, respectively, and extending within the area of the through holes. Fig. 6 is a cross-sectional view of the capacitive sensor film 50 of Fig. 5 along the line BB indicated in Fig. 5. Fig. 7 is the cross-sectional view of the film of capacitive sensor 50 of FIG. 5 further comprising two protective layers 16 and 17. FIG. 8 is the cross-sectional view of the capacitive sensor film of FIG. 5 with a plug 31 applied to the rear main surface 51 of FIG. the film 50. DETAILED DESCRIPTION OF THE INVENTION The term "film" as used above and will be used below refers to an article that has an extension in two directions which exceed the extent in a third direction which is essentially normal to the two directions by a factor of at least 5 and more preferably at least 10. More generally, the term "film" is used herein to refer to a flexible sheet-like material, and includes sheets, thin sheets of metal, strips, laminates, tapes and the like. The term "electrically insulative" as used above and will be used below refers to materials having a specific mass resistivity as measured in accordance with ASTM D 257 of at least 1 x 1012 Ohm. centrimeters (Ocm) and more preferably of at least 1 x 1013 Ocm. The term "electrically conductive" as used above and as will be used below refers to materials having a surface resistivity as measured in accordance with ASTM B193-01 of less than 1 Oh / square centimeter (O / cm 2). Generally, the capacitive sensor film 50 comprises an electrically insulating reinforcing layer 2 carrying on one of its main surfaces a protective conductor 1 and on its opposite major surface a sensor conductor 7. The reinforcing layer is preferably continuous and preferably has a thickness of between 20-500 micrometers (μm), in some modalities, between 25-350 μm and in some modalities, between 25-150 μm. Suitable reinforcing materials include, for example, polymeric films and layers, paper films and layers, layers of nonwoven, laminates (such as, for example, polyacrylate foams laminated on both sides with polyolefin films, and laminated or coated papers). soldiers with template with polyethylene terephthalate) and combinations thereof.

Useful polymer films and layers include, for example, polyolefin polymers, monoaxially oriented polypropylene (MOPP), biaxially oriented polypropylene.

(BOPP), biaxially oriented polypropylene simultaneously (SBOPP), polyethylene, polypropylene and polyethylene copolymers, polyvinyl chloride, copolymers having a predominant olefin monomer which may optionally be chlorinated or fluorinated, polyester polymers, polycarbonate polymers, polymethacrylate polymers, cellulose acetate, polyester (for example biaxially oriented terephthalate), vinyl acetates, and combinations thereof. Useful reinforcements also include modified modified surface reinforcements by, for example, plasma discharge techniques that include corona discharge treatment and flame treatment, mechanical scraping and chemical primers. The protective conductor 1 comprises an electrically conductive material and, in some embodiments, one or more metals which are applied as a layer or a film to one of the main surfaces of the reinforcing layer 2. In some embodiments, the conductor Protection 1 comprises an aluminum layer. The protective conductor can be formed, for example, by a metal film which is bonded to the main surface of the reinforcing layer 2 with a layer of adhesive 3 such as, for example, a layer of pressure-sensitive adhesive. The protective conductor 1 can also be applied directly to the main surface of the reinforcing layer 2, for example, by vacuum metal vapor deposition. The thickness of the protective conductor 1 can vary widely depending on the method of manufacturing it. A layer of protective conductor 1 obtained by metal vapor deposition in vacuum can be as fine as 200-800 Angstroms (Á) and in some embodiments, 300-500Á. When a thin sheet of aluminum is used as a protective layer 1 it may preferably have a thickness of 1-100 μm, in some embodiments, 2-50 μm and in some embodiments, 3-30 μm. The protective conductor 1 acts as a shield to reduce the sensitivity of the sensor conductor 7 to anything behind it in the body direction. In automotive applications, for example, it is desirable for sensor driver 7 to detect objects that are generally toward the exterior of the vehicle but is effectively blind to the interior of the vehicle. Therefore the dimensions of the protective conductor 1 are preferably chosen to at least equal those of the sensor conductor 7 but in some embodiments, the dimensions of the protective conductor 1 at least partially exceed those of the sensor conductor. In some embodiments, the protective conductor 1 essentially completely covers the main side of the reinforcing layer 2 to which it is fixed. The sensor conductor 7 is disposed on the main surface of the reinforcement 2 which is opposite the main surface with the protective conductor. The sensor conductor 7 comprises an electrically conductive material and, in some embodiments, one or more metals. In some embodiments the sensor conductor 7 comprises a relatively inexpensive material such as an aluminum layer which can be applied by metal vapor deposition in vacuum or as an aluminum film or thin sheet of metal which can be attached to the reinforcement 2, example, by a layer of adhesive such as, for example, a pressure sensitive adhesive. In another embodiment, the sensor conductor 7 comprises a copper layer or plated copper layer as a conductive material which can be used, for example, in the form of optionally flattened wires which are applied to the reinforcing layer, for example, by an adhesive layer 9. The sensor conductor can also comprise a copper layer which can be applied, for example, by metal vapor deposition under vacuum or as a thin sheet or bonded copper film. The sensor conductor 7 can assume a variety of shape and can exhibit a continuous or discontinuous configuration, respectively. In automotive applications where the capacitive sensor film is attached, for example, to the rear side of a carriage, the sensor conductor may be in the form of an elongated strip. In British Patent 2,348,505 it is described that the sensor conductor 7 can be a strip comprising lobes in its two end regions in the longitudinal direction, ie, the sensor conductor is wider in its end regions in the longitudinal direction that in its central portion. In use, the lobes are positioned at the ends of the bumper at the edges of a vehicle to provide a more uniform sensitivity along the width of the carriage. In some embodiments the sensor conductor 7 comprises a sequence of strips extending essentially in a longitudinal direction (i.e., for example, essentially along and parallel to the length of the reinforcement layer 2). The strips can be formed by optionally flattened metal wires or strips of a thin sheet of metal. If the strips are arranged essentially parallel to each other, another strip can be provided in a transverse direction for electrically connecting the cables arranged in the longitudinal direction. The sensor conductors 7 comprise a discontinuous arrangement of conductive areas as an arrangement of optionally flattened wires so that those areas which are electrically connected, exhibit a particularly advantageous sensitivity and may be preferred. The thickness of the sensor conductor 7 can vary widely depending on the manufacturing method. Sensor conductors optionally comprising flattened metal cables exhibit a thickness generally of between 20 and 200 μm and, in some embodiments, between 25 and 100 μm. Sensor conductors 7 obtained by vacuum vapor deposition can be as fine as 200-800 Á and, in some embodiments, 300-500 Á. When a thin sheet of aluminum is used as a sensor layer 7 it may have a thickness of 1-100 μm, in some embodiments, 2-50 μm and in some embodiments, 3-30 μm. The capacitive sensor film 50 of the present disclosure may further comprise a maximum protective conductor 5 which may be disposed on the surface of the reinforcement 2 carrying the sensor conductor 7. The maximum protective conductor is provided to reduce the sensitivity of the conductor from sensor 7 to the presence of very close objects that the sensor driver is not required to detect. In automotive applications, the maximum protective conductor 5 can be arranged - relative to the level of the road - above or below the sensor conductor. In use, an amplified protection signal can be applied to the maximum protection contutor 5 which has the effect of making the protection appear larger. According to British Patent GB 2,374,422 this can be effective in automotive applications when the proximity sensor 5 is assembled, for example in the bumper on the rear side of a carriage, to minimize the trickling effect of water running down in conditions of rainy weather through the bumper, in the signal of the sensor conductor 7. The maximum protection conductor 5 comprises an electrically conductive material and, in some modalities, one or more metals. In some embodiments, the maximum protective conductor 5 comprises a relatively inexpensive material such as an aluminum layer which can be applied to the reinforcement 2 'as a thin sheet or aluminum film, respectively, by means of, for example, a layer of adhesive such as a pressure sensitive adhesive layer. In another embodiment, the maximum protection conductor 5 may comprise a metal layer such as a layer of copper or aluminum applied to the reinforcement layer 2 by vacuum vapor deposition. Alternatively, it is also possible to apply the coating layer by means of a metal vapor deposition in vacuum to a carrier film comprising, for example, a polymer layer, the carrier film carrying the metallic coating layer is then fixed, for example by means of a adhesive layer to the reinforcement layer 2. In yet another embodiment the maximum protective conductor may be discontinuous and formed, for example, by flattened metal cables which are fixed to the stress layer 2, for example, by a layer of adhesive. The maximum protection conductor 5, if present, can assume a variety of forms and can be continuous or discontinuous, respectively. In automotive applications where the capacitive sensor film 50 is assembled within the bumper of the rear side of a vehicle, for example, the maximum protective conductor 5 can advantageously assume the shape of an elongated strip extending along the rear side bumper. The thickness of the maximum protective conductor 5 can vary widely depending on the manufacturing method. The layers 5 of the maximum protection conductor obtained by metal vapor deposition can be as fine as 200-800 Á, in some embodiments, 300-500 Á. When a thin sheet of aluminum is used as a maximum protective conductor layer 5 it may have a thickness of 1-100 μm, in some embodiments, 2-50 μm and in some embodiments, 3-30 μm. As described above, the protective conductor 1, the sensor conductor 7, and if present, the maximum protective conductor 5 of the capacitive sensor film 50. of some embodiments of the present disclosure are electrically contacted from one of the major surfaces 51, 52 (Fig. 8) of the film. The upper main surface 51 of the film 50 can be formed by the exposed surface of the protective conductor, or if present, by the exposed surface of a back protective layer 17 (see below). The front main surface 52 of the film 50 can be formed by the front main surface 2b of the reinforcing layer 2 or the exposed surfaces of the sensor conductor 7 or the maximum protective conductor 5, respectively, or if present, by the surface exposed from a front protective layer 16 (see below). With a view to establish electrical contact with the conductors 1,5,7, the capacitive sensor film 50 of some embodiments of the present description comprises at least one through hole 10 extending through the reinforcement layer 2 towards a of the main surfaces 51, 42 of the film 50. In case the electrical connections are made to the capacitive sensor film 50 from its rear main surface 51, the sensor conductor 7, if present, the maximum protective conductor 5 can be contacted through one or more through holes 10. Similarly, in the event that the film 50 is electrically contacted from its front main surface 52, the protective conductor 1 can be contacted through one or more through holes. 10. The one or more through holes 10 can be applied by any die or perforated cutting device such as, for example, by an orifice puncher. mechanical or pneumatic operation, turned wedge or rotating block. The cross section of the through holes 10 can have any shape including, for example, a circular, ellipsoidal, rectangular or irregular shape. The cross-sectional dimension of the through-holes 10 is not critical and is selected to allow a reliable electrical connection while not adversely affecting the laminate integrity of the capacitive sensor. In some embodiments, the cross-sectional dimension of the through holes varies between 0.1 and 5 square centimeters (cm2) and, in some embodiments, between 0.5 and 2.5 cm2. One or more through holes 10 can be arranged inside or outside the area of the protective conductor 1, the sensor conductor 7 and / or - if present - the maximum protective conductor 5. If the through hole 10 is arranged, for example , within the area of the sensor conductor 7 inside a capacitive sensor film 50 which is electrically contacted from its rear surface 51, such through holes 10 may or may not extend through the sensor conductor 7. In some embodiments, one or more through holes 10 extend toward the rear surface of the sensor wire 7 but do not extend through the sensor wire 7. In this embodiment the rear surface of the sensor wire 7 can be easily contacted through one or more through holes 10 from the rear surface 51 of the laminate. In this embodiment it is alternatively also possible for one or more through holes 10 to extend through the sensor conductor 7 in such a way that the front surface of the sensor conductor 7 can be contacted through one or more through holes 10 from the rear side. 51 of the laminate. Similarly, if a maximum protective conductor 5 is present and the capacitive sensor film 50 is contacted from its rear side 51, such contact can be made through one or more additional through holes which can terminate at the rear surface of the maximum protection conductor 5 or extend through the maximum protection conductor 5, respectively. It is also possible for the sensor conductor 7 and the maximum protective conductor 5 to be contacted through a through hole 10. If the capacitive sensor film 50 is contacted from its front surface 52, one or more through holes 10 may extend from similarly towards the front surface of the protective conductor 1 or extend through the protective conductor 1, respectively. However, it is also possible that one or more through holes 10 are arranged outside the area of the protective conductor 1, the sensor conductor 7 and / or if present the maximum protective conductor 5. In some embodiments, in a film of capacitive sensor 50 of the present description which is electrically contacted from its rear side 51, one or more through holes 10 are disposed outside the area of the sensor conductor 7 and / or the maximum protective conductor 5, if present. In this case, one or more auxiliary conductors 12, 13 (Fig. 5) can be provided which are electrically connected to the sensor conductor 7, and if present, to the maximum protective conductor 5. Auxiliary conductors 12, 13 they can be formed, for example, by electrically conductive adhesive tapes comprising a reinforcement carrying an electrically conductive adhesive. A strip of such tape is fixed via its electrically conductive adhesive layer to the sensor conductor 7, and the length of such adhesive strip is selected such that it extends within the area of the through hole 10. Thus, the sensor conductor 7 it can be electrically connected from the rear side 51 of the capacitive sensor film 50 via such an auxiliary conductive adhesive strip. If the capacitive sensor film additionally comprises a maximum protective conductor 5, a separate auxiliary conductor 13 which can be an electrically conductive adhesive strip can be provided and electrically connected to the maximum protective conductor 5. Such a strip extends within the area of the through hole 10 without contacting the adhesive strip 12 attached to the sensor conductor 7. Auxiliary conductors 12, 13 can also be formed by thin sheets of metal or carrier films carrying a metallic coating layer obtained, for example, by vacuum metal vapor deposition. Such conductors 12, 13 are applied in such a way that the thin metal sheet or the metal coating layer contacts the sensor conductor 7 and, if present, the maximum protective conductor 5, and these can be maintained in their place, for example, by conventional one-sided adhesive tapes. The reinforcement of an electrically conductive adhesive tape which can be used as auxiliary conductor 12, 13, can include electrically non-conductive and conductive materials such as metallic films or polymeric films. Conductive film tapes comprising a copper or aluminum foil reinforcement, respectively, each carrying an electrically conductive pressure sensitive adhesive, are commercially available from 3M Company, St. Paul / MN, USA, under the designations of trademark "3M 1170 EMI Aluminum Foil Shielding Tape" and "3M 1181 EMI Copper Foil Shielding Tape", respectively. A thin sheet of aluminum having a thickness of 20 μm which can be used as a conductor 12, 13 is available, for example, from Tesco Comp. Under the designation "thin sheet of metal for cooking". The conductor 12 can be formed generally by any material which can be attached to the sensor conductor 7, or if present, to the maximum protective conductor 5 in an electrically connected manner and which is sufficiently self-supporting in such a way as to provide a reliable electrical contact area within the area of the through hole 10. The conductor 12 can also be formed, for example, by an optionally flattened metal cable which is fixed to the sensor conductor 7 and the maximum protective conductor 5 by means of a electrically conductive adhesive. An electrically insulating film 11 is applied to completely cover one or more through holes 10 on the front and / or back side of the reinforcing layer 2, respectively, before applying the conductors 12, 13. Such an electrically insulating film comprises a reinforcing which can be formed, for example, by any non-conductive paper or polymer film. Useful non-conductive polymeric materials include, for example, polyolefin polymers, monoaxially oriented polypropylene (MOPP), biaxially oriented polypropylene (BOPP), biaxially oriented polypropylene (SBOPP) simultaneously, polyethylene, polypropylene and polyethylene copolymers, polyvinyl chloride, copolymers which have a predominant olefin monomer which can optionally be chlorinated or fluorinated, polyester polymers, polycarbonate polymers, polymethacrylate polymers, cellulose acetate, polyester (e.g. biaxially oriented polyethylene terephthalate) d, vinyl acetates, and combinations of same. The electrically insulating film 11 carries an adhesive layer 6 and, in particular, a pressure-sensitive adhesive layer on one of its main surfaces through which it is fixed to the front and / or back side of the capacitive sensor film 50. The electrically insulating film 11 is applied to the front main surface of the reinforcing film 2 and / or to the exposed surface of the protective conductor 1 in such a way that it completely covers the through hole 10 in each case. perforate through one or more electrically insulating films in such a way that the through hole 10 is restored which now further extends through the insulating films. The cross-sectional and / or shape extension of the holes drilled within the electrically insulating films are selected such that the hole drilled through the insulating film is smaller than the originally drilled through hole. The edges of the electrically insulating films 11 that extend within the area of the through hole 10, they are attached to the inner wall of the through hole 10 thus electrically isolating the protective conductor 1 from the sensor from the sensor conductor 7, and if present, from the maximum protective conductor 5. In some embodiments, the length of the edges of the electrically insulating films 11 extending within the area of the through hole 10 is selected in such a way that the inner wall of the through hole is essentially completely covered by the electrically insulating films 11. This specific design reliably insulates the protective conductor 1. of the sensor conductor 7 and, optionally, the maximum protective conductor 5 and additionally reinforces the area of the through hole 10. Electrically insulating films 11 can both be applied to the front main surface 2b of the reinforcement film 2 and to the exposed surface of the conductor of protection 1 of the through hole 10. The modality and emp Previous luting has been described for the case that the capacitive sensor film 50 is contacted from its rear main surface 51. However, it is also possible that the capacitive sensor film 50 is contacted from its front main surface 52. In such case one or more through holes 10 will extend from the front main surface 52 towards the front surface of the protection conductor through the protective conductor towards its rear surface, respectively. If the protective conductor does not completely cover the rear main surface 2a of the reinforcement 2 and one or more through holes are disposed outside the area of the protective conductor 1, one or more auxiliary conductors 12, 13 and, if desired, a or more insulating films 11 as described above to allow an easy and reliable connection. In some applications it is desirable to seal the capacitive sensor film 50 between the protective films 16, 17 to protect the capacitive sensor film 50 against environmental impacts such as water or moisture, to electrically isolate the film 50 and / or to provide the latter with greater easy handling capacity. Such protective films can be selected from the group of polymer films, layers and laminates. Useful polymers include, for example, polyolefin polymers, monoaxially oriented polypropylene (MOPP), biaxially oriented polypropylene (BOPP), biaxially oriented polypropylene (SBOPP) simultaneously, polyethylene, polypropylene and polyethylene copolymers, polyester polymers, polycarbonate polymers, polymers of polymethacrylate, cellulose acetate, polyester (for example biaxially oriented polyethylene terephthalate), vinyl acetates, and combinations thereof. Protective polymer films can be applied to the front main surface 2a of the reinforcing layer carrying the sensor conductor 7 and, optionally, the maximum protective conductor 5 and to the protective conductor 1 on the rear main surface 2a of the reinforcement 2 or adhesive means including, for example, hot melt adhesives and pressure sensitive adhesives. In another embodiment, the protective film can also be hot rolled on the front main surface 2b of the reinforcing layer 2 and the protective conductor 1, respectively. In some embodiments, the length and width of the protective films 16, 17 preferably exceed the length and width of the reinforcing film 2 and / or the protective conductor 1 to provide an edge seal to the capacitive sensor film 50. protect, in particular, the rims of the corrosion protection conductor. In some embodiments, the length and width of the protective films 16, 17 is preferably selected to provide an edge sealing limit with a width of 1-50 millimeters (mm), in some embodiments, of 1-40 mm and, in some modalities, of 2-20 mm. In some embodiments, particularly in automotive applications, to include cuts and darts within the capacitive sensor film 50 such that the film can better conform to three-dimensional curvatures such as, for example, the inner lining of the bumper. This allows the film 50 to extend essentially flat to the inner liner of the bumper if it forms undesirable folds to an unacceptable degree. This applies to both sealed edge films 50 comprising at least protective film 16, 17 and films without sealed edge 50. One or more through holes 10 can be punched into the protective film 16, 17 onto the main surface of the film of capacitive sensor 50 from which the capacitive sensor film 50 is contacted thereby extending the through holes towards the surface. In the event that the capacitive sensor film 50 is contacted from its rear main surface 51, an additional hole can be drilled into the protective layer 17 to allow the protective conductor 1 to be contacted. Similarly, in the case where the capacitive sensor 50 is contacted from its front main surface 52, one or more additional holes can be drilled within the protective layer 16 to allow contacting the sensor conductor 7 and, optionally, the maximum protective conductor 5 while the protective conductor 1 is contact via one or more through holes 10. Alternatively, one or more holes may be drilled in appropriate locations within the protective film 16, 17 prior to lamination in such a manner that the pre-drilled holes extend the through holes or holes 10 toward the respective major surface of the capacitive sensor film 50 and / or provide access to the conducts Desired items 1, 7 and / or 5. Cable or strip connection 33 is supplied through one or more through holes 10 or through additional holes which may be present to contact the protective conductor 1, the sensor conductor 7 and, optionally, the maximum protective conductor 5 and / or any auxiliary conductors 12, 13 which can be fixed to the conductors 1, 7, 5. If the capacitive sensor film 50 is contacted, for example from its rear main surface 51 , the connecting strips 33 are supplied from the rear side 51 of the capacitive sensor film 50 through one or more through holes 10 and press against the sensor conductor 7, the maximum protective conductor 5 and / or the auxiliary conductors 12, 13, respectively, establish electrical contact. Pressure can be applied, for example, via spring-loaded bearings which continuously press on the areas of connection between the connectors and the sensor conductor 7, the maximum protective conductor 5 and / or the auxiliary conductors 12, 13 respectively. In some embodiments, one or more through holes 10 may be adjusted to be filled with a conductive ink such as silver ink which subsequently solidifies by drying or curing by evaporation. The through hole 10 can also be filled, for example, with a precursor of a silver epoxy adhesive which is thermally cured under insertion into one or more through holes 10. In these constructions the connecting strips 33 need not be supplied through the through holes 10 but can be applied, for example, to the respective main surface 51, 52 of the capacitive sensor film 50. Establish the electrical contact between the connectors and the sensor conductor 7, the maximum protective conductor 5 and / or the conductors 12, 13 are thus provided, and the resulting connection is more reliable and mechanically stable. The capacitive sensor film 50 of some embodiments of the present disclosure can thus be electrically contacted reliably and easily from one of its major surfaces., 52. Contacting the capacitive sensor film 50 from its rear main surface 51 is particularly preferred in automotive applications. It is usually desirable to integrate the connectors by contacting the protective conductor 1, the sensor conductor 7 and, optionally, the superconnection conductor 5 and / or the conductors 12, 13 in a plug body 31 (Fig. 8) which can be applied to the capacitive sensor film 50 to allow a standardized connection. In some embodiments, a complete hermetic seal is preferably formed between the periphery of the plug body 31 and the film surface of the capacitive sensor 50, thus preventing water, air or dust from entering the connection area. In one embodiment, the plug body 31 comprises sealing means such as O 32 sealing rings around its periphery by contacting the capacitive sensor film 50. The plug body 31 is applied to the capacitive sensor film 50 in such a manner that the O seal rings are pressurized and form the required hermetic seal. The capacitive sensor film 50 of some embodiments of the present disclosure can be advantageously used in automotive applications to detect the proximity of a carriage to other objects where it can be introduced, for example, into the rear and front bumper. The capacitive sensor film 50 can be cut into the shape required by any cutting wedge, punch or laser cutting means, for example, because of its flexibility it can be easily processed and bent in accordance with the shape of the bumper, if requires It is particularly advantageous that the capacitive sensor film 50 can be easily connected electronically from its rear side which not only facilitates the assembly in the OEM site (original equipment manufacturer) but also allows, for example, an easy placement of such a film in such a manner. 50 capacitive sensor film if the bumper incorporates damage in an accident. The capacitive sensor films 50 of some embodiments of the present disclosure can be easily installed and are flexible in such a way that they can be applied to molded substrates having, for example, curved surfaces. It is particularly advantageous that the capacitive sensor films 50 can be electrically contacted in an easy and reliable manner. In view of these advantages the capacitive sensor films 50 of the present disclosure are especially suitable for use in the automotive industry. Devices which are suitable for measuring and processing signals from the sensor conductor 7 have been described, for example, in WO 02/19,524 and are not further described here. It will be understood that the particular configurations shown in the figures for the sensor and protective conductors and the optional maximum protective conductor are for illustration purposes only and are not an essential feature of the invention. The proximity sensors described herein with reference to the figures are particularly suitable for use in vehicle bumpers but the manner in which the electrical connection is made from one side of the capacitive sensor film to the sensor and protective conductors (and when present, the maximum protective conductor) is applicable to sensor films intended for use in other applications and to sensor films with differently configured conductors including, for example, sensor films with a sensor-shaped conductor. serpentine or spiral or with two sensor conductors intertwined, or with a multiplicity of protective conductors. In a manufacturing method a capacitive sensor film 50 of the present disclosure which can be contacted from one of its main surfaces 51, 52, an aluminum film laminate comprising the reinforcement layer 2 carrying an aluminum layer which forms the protective conductor 1, is provided first. The sensor conductor 7 and the maximum protective conductor 5, if present, can be films or thin sheets of metal which are applied to the other main surface of the reinforcing layer 2 which is opposite to the protective layer 1 , for example, by adhesive means. Alternatively, the sensor conductor 7 and the maximum protective conductor 5, if present, can also be applied by vacuum vapor metal coating. Then one or more through holes 10 are applied to the reinforcement layer 2. If the capacitive sensor film 50 is to be contacted, for example, from its rear main surface 51 and if one or more through holes extend into the area of the sensor conductor 7 and, optionally, the maximum protective conductor 5, such through holes 10 can be drilled from the rear main surface 51 such that they extend toward the rear surface of the conductors 7, 5 facing the reinforcing layer 2 Alternatively, the through holes 10 can be drilled into the reinforcing layer 2 and the protective conductor 1 first, and the sensor conductor 7 and, if present, maximum protective conductor 5 are subsequently applied. In another embodiment one or more through holes 10 can extend through the sensor conductor 7, and if present, the maximum protective conductor 5. If the capacitive sensor film 50 is contacted, for example, from its rear main surfaces 51 but if the through holes 10 are applied outside the area of the sensor conductor 7 and the maximum protective conductor 5, auxiliary conductors 12, 13 can be applied in such a way that they are electrically connected to the sensor conductor 7, and if present , to the maximum protective conductor 5. The auxiliary conductors 12, 13 extend within the area of one or more through holes 10 and can be contacted from the rear main surface 51 of the laminate. If the capacitive sensor film 50 is to be contacted from front main surface 52, one or more through holes are applied analogously to the embodiments described above to allow contact with the protective conductor 1. One or more through holes typically extend in the area of the protective conductor 1 which generally covers at least the main part of the rear main surface 2a of the backing layer 2. The through holes 10 can extend towards the front surface of the protective conductor 1 oriented towards the backing layer. reinforcement 2, or may also extend through the protective conductor 1. In the latter case the auxiliary conductors 12, 13 may be used to facilitate providing electrical connections. In each case, after the formation of a through hole 10, an insulating film 11 is applied over the hole and a smaller hole is then drilled in the film in such a way that the surrounding edges of the film extend inside, and cover the the original orifice wall 10 for isolating the protective conductor 1 from the sensor conductor 7 (or, when present, the maximum protective conductor 5). In some embodiments, the portion (s) bent into the film (s) 11 preferably covers the entire wall of the hole 10 but can cover only a portion thereof, sufficient to avoid inadvertent electrical connection, via the orifice. 10, from the protective conductor to the maximum protective conductor or sensor. In some embodiments, the protective layers 16, 17 are sealed to the capacitive sensor film 50, for example, by heat lamination or by means of a hot melt adhesive. One or more holes are arranged on one or more through holes 10 and / or in the case of the film 50 is contacted, for example, from its rear main surface, on the protective conductor 1 which may be perforated inside the protective films 16, 17 before applying these. Alternatively, such a hole or holes can subsequently be applied to seal the protective films 16, 17 to the capacitive sensor film 50. The capacitive sensor film 50 can be manufactured continuously. In such a case the capacitive sensor film 50 is cut from the continuous frame. The capacitive sensor film 50 is cut into the required shape, for example, by wedge cutting, laser cutting or a V-shaped knife on an XY table cutter. Electrical contact is then provided from one of the main surfaces 51, 52 of the film through one or more through holes 10, for example, by pressure contact. Contact can be facilitated by filling the through holes 10 with a conductive fluid, such as, for example, a silver ink or a silver epoxy adhesive which can subsequently be cured or heat dried. If the capacitive sensor film 50 is electrically connected from its rear main surface 51, the contact can be made through through holes 10 towards the sensor conductor 7 and, optionally, the maximum protective conductor 5. The protective conductor 1 can contacting in this embodiment for example, by an additional hole drilled within the back protective layer 17. The protective films 16, 17 are usually larger than the reinforcing layer 2 such that the protective films 16, 17 provide a sealing of edge. These manufacturing methods are highly advantageous because they can be operated continuously or semi-continuously, and these can also be included in the automobile manufacturing lines, for example. The following figures are schematic and are not shown to scale. Fig. 1 shows a top view of a precursor of a modality of the capacitive sensor film 50 of the present disclosure comprising a backup layer 2 carrying a sensor conductor 7 disposed in the sensor area 4 and a maximum protective conductor 5. The sensor conductor 7 exhibits a discontinuous design and is composed of several optionally flattened metal wires extending parallel to the long side of the reinforcing layer 2, ie, in a longitudinal direction. At both ends the sensor conductor 7 comprises additional shorter pieces of such wire to provide lobe-like end regions to increase the sensitivity of the sensor conductor 7 at its end regions. The different cables of the sensor conductor 7 are connected in both regions by two cables each extending transversely inclined in the direction of the long side of the reinforcing layer 2. The maximum protective conductor 5 is formed by a final metal strip extending in parallel to the long side of the reinforcing layer 2. Fig. 2 is a cross-sectional view of the precursor film of Fig. 1 along the line AA indicated in Fig. 1. The protective layer 1 it extends along the entire width of the reinforcing layer 2 and is fixed thereto by means of the adhesive layer 3. The maximum protective conductor 5 and the cables forming the sensor conduit 7 are fixed by the adhesive layers 8. , 9 towards the front main surface of the reinforcing layer 2 which is opposite to the protective layer 1. The metal wires or metal strips of the sensor conductor 7 are integrated in the adhesive layer 9 but are also possible. for example, that the metal wires or metal strips are each fixed by adhesive points. The small square that resides in the upper part of the wires or strips integrated in the adhesive layer corresponds to the transversely inclined wire or strip connecting the integrated wires or strips. Fig. 3 is a top view of a capacitive sensor film obtained from the precursor of Fig. 1 by applying two through holes 10 in area between the maximum protective conductor 5 and the sensor conductor 7. Fig. 4 is a top view of the capacitive sensor film 50 of FIG. 3 wherein an electrically insulating film 11 has been applied to the front surface of the reinforcing layer 2 such that it covers the two through holes 10 created initially. Subsequently, the holes have been drilled into the insulating film 11 to restore the through hole 10. The holes drilled within the insulating film 11 are smaller than the through holes 10 created initially. Fig. 5 is a top view of the capacitive sensor film 50 of Figs. 3 and 4 where auxiliary conductors 12, 13 have been applied extending from the maximum protective conductor 5 and the sensor conductor 7, respectively, into the respective through-hole area 10. The capacitive sensor film has already been cut in the form required for insertion inside car bumpers. Fig. 6 is a cross-sectional view of the capacitive sensor film 50 of Fig. 5 along the line BB indicated in Fig. 5. It can be seen that the insulating film 11 has been applied to both the side front and rear side of the capacitive sensor film 50, and holes have been drilled into the insulating film 11 which is smaller than the through hole 10 created initially, causing the surrounding edges of the film to extend inside, and cover the wall of the orifice 10. The insulating film 11 comprises an adhesive layer 6 which keeps the insulating film 11 in place. The auxiliary conductor 13 comprises a reinforcement 15 and an electrically conductive adhesive layer 14 is fixed to the sensor conductor 7 and extends over the through hole 10 towards the insulating film 11 on the opposite sides of the hole. It can be seen that the sensor conductor 7 is electrically connectable via the through hole 10 from the rear side of the capacitive sensor film 50 but the electrical contact with the protective conductor 1 is prevented by the inwardly folded portions of the insulating films 11. Fig. 7 and Fig. 8 are cross-sectional views of the capacitive sensor film 50 of Fig. 5 along the line BB of Fig. 5 further comprising protective layers 16, 17 sealed over both the front and rear main surface 2a, 2b of reinforcement 2 by means of a hot melt adhesive 18 (not shown). An orifice has been cut into the protective layer 17 applied to the rear main surface 2a of the reinforcing layer 2 to extend the through hole 10 towards the back surface of the protective layer 17. The width of the through hole 10 in the protective layer 17 exceeds the width of the through hole 10 in the backing layer in such a way that the connecting strips 33 in contact with the protective conductor 1, the sensor conductor 7 and the maximum protective conductor 5 can be integrated into a housing plug 31. This is shown in Fig. 8 which is a cross-sectional view of the capacitive sensor film 50 of Fig. 5 along the line BB where the capacitive sensor film additionally comprises a plug 31 which is applied to the rear main surface 51 of the capacitive sensor film 50. The protective conductor 1 and the connector 13 (which is electrically connected to the conductor d sensor 7) are connected to the connecting strips 33 which are fed into the plug 31. The plug 31 comprises O 32 sealing rings which are pressurized and form a hermetic seal. An adhesive seal can be used in place of the O seal ring. Modalities of the present disclosure are further illustrated in the following non-limiting Examples.

EXAMPLES Example 1 A conventional thin aluminum foil (thickness 20 μm) which is available from Tesco Comp., UK, as a thin cooking foil was laminated to a polyethylene terephthalate (PET) film carrying an adhesive layer of vinylethylene acetate (EVA). The PET film carrying the adhesive layer is available from GBC, UK. The lamination was carried out at a temperature of approximately 110 QC using a laminator of the office type. The aluminum layer acted as a protective layer. On the main side of the PET film opposite the aluminum protective layer a 12 mm wide aluminum foil tape available from 3M Company under the designation "3M Aluminum Foil Tape 425" was applied along the length complete of the PET film. This strip tape acted as a maximum protection layer. Then a double-sided adhesive tape (available from 3M Company under the designation 9512 was applied to the main surface of the reinforcing layer opposite the protective layer and then the maximum protection layer.) A sequence of flattened copper wires (thin-veneered copper wires, 50 μm thick and 0.5 mm wide, available from Chaplin Bros, Birmingham UK) which extend along the length of the PET film were applied to the exposed surface of the adhesive tape The wires are each parallel to the long side of the PET film (ie extended in a longitudinal direction) and spaced 5 mm apart.The wires arranged in parallel in the longitudinal direction were electrically connected to each other by another wire. flattened copper extending in a direction inclined transversely with respect to the longitudinal direction.This discontinuous arrangement or flattened wires formed the After that, the connector holes were drilled in the area of the reinforcement layer between the protective conductor and the maximum protective conductor through the reinforcement layer and the protective conductor using the hole drilled by the engineer. . Then a polyester film pressure sensitive adhesive tape (8417, available from 3M) was applied to the front main surface of the reinforcing layer and the exposed surface of the protective layer, respectively, in such a way that the through hole it was covered on the front and back side of the reinforcing layer. Then a hole, smaller than the original hole was cut through the polyester films, to obtain an insulating ring. The aluminum foil tape (To 1170 tape, available from 3M) and copper foil tape was applied (Copper foil tape: Cu tape 1181, available from 3M). A tape of a laminate formed of aluminum foil conductive adhesive tape 1170, 5 mm in width and a piece of 25 mm in width of polyester tape 8417 was electrically connected to the sensor conductor in such a way that the opposite end was extended inside the area of one of the through holes. One strip of a 1181.5mm wide copper foil conductive adhesive tape laminate on a 25mm wide piece of 8417 polyester tape was electrically connected to the maximum protective conductor in such a way that the opposite end was extended inside. from the area of the other through hole. Laminate strips were applied in such a way that there is a gap of 5 mm between the two strips of conductive tape. Thus the film of the capacitive sensor obtained afterwards was laminated between two pieces of protective heat sealing polyester film (50 μ PET film with 25 μ EVA heat sealing adhesive, available from GBC, UK). Appropriate holes were cut within the protective polyester film applied to those areas on the back side of the capacitive sensor film covering the through holes. Finally, a conductive silver ink obtained from Sun Chemicals was filled into the through holes and dried. Then a plug body was applied. The capacitive sensor film was cut to the shape and the connector was applied to make the electrical contacts. Example 2 Example 1 was repeated using a thin film of aluminum with a thickness of 6.35 μm obtainable from Alean, UK, which was laminated to a thickness of 80 μm filled with polypropylene film obtainable from RKW, Sweden, under the trademark designation FPO carrying a layer of 20 μm vinyl ethylene acetate adhesive. The FPO film is a blown film comprising calcium carbonate and talc particles which are joined in a polypropylene matrix. The aluminum foil was laminated to the adhesive layer in the FPO film at a temperature of 90 SC using an office type laminator. Then the sensor conductor and the maximum protective conductor are applied and the through holes are provided, covered with tape 8417 and punched to provide holes smaller than the original through hole as described in Example 1. Then a strip of a formed laminate of a strip with 5 mm width of a thin aluminum film (20 μm thickness, available from Tesco Comp., UK, as a cooking film) and a strip of 25 mm width of 8417 polyester tape were connected electrically to each of the sensor conductor and maximum protective conductor, respectively, so that the opposite end was extended within the area of one of the through holes each. The other details were selected as described in Example 1. The resulting capacitive sensor film was laminated between two protective FPO and heat films (thickness of 60 μm with an EVA layer of 25 μm EVA) as described in Example 1. The connections were made by contact with pressure forming a cross section through each connection area, pushing through a small machine screw, applying a washer and a nut to the side of the protective conductor and pressing down to form an electrical contact with the sensor conductor and the maximum protection conductors, respectively. Example 3 Example 1 was repeated but an aluminized film comprising a PET film of 12 μm carrying an aluminum vapor coating of 300-500 A (available from A cor, UK) laminated to an FPO film as in Example 2 was used in place of the lamination of the thin film Al and the PET film. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (13)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A capacitive sensor film for mounting to a body, characterized in that it comprises a reinforcing dielectric layer having, on one side, a rear main surface oriented, in use, to the body and, on the other side, a front main surface, the rear main surface carrying a protective conductor and the front main surface carrying a sensor conductor, and at least one through hole defined by a wall inner extending through the reinforcing layer to allow electrical contact with one of the conductors from the opposite side respectively of the film, wherein the inner wall of the through hole is covered, at least partially, by an electrically insulating film.
2. 2. Capacitive sensor film according to claim 1, characterized in that the main front surface additionally carries a maximum protective conductor, and where electrical contact with the protective conductor of maximum protection can be made from the side of the film from the which the protective conductor and the sensor conductor can be contacted.
3. 3. Capacitive sensor film according to claim 1 or 2, characterized in that the electrically insulating film extends into the through hole from at least one of the main surfaces of the reinforcing layer.
4. Capacitive sensor film according to any of the preceding claims, characterized in that in which the electrically insulating film adheres to the inner wall of the through hole.
5. 5. Capacitive sensor film according to any of the preceding claims, characterized in that the / each through hole is arranged in such a way that it does not extend through the area of the sensor conductor.
6. Capacitive sensor film according to claim 5, characterized in that an auxiliary connector is electrically connected to the sensor conductor and extends essentially parallel to the front main surface of the reinforcing layer at least partially over the through hole.
7. Capacitive sensor film according to any of the preceding claims, characterized in that the protective conductor, the sensor conductor and, if present, the maximum protective layer are provided with electrical connectors in such a way that such connectors can be powered inside a plug which is disposed on one side of the film, wherein one of the electrical connectors extends through the through hole.
8. Capacitive sensor film according to any one of claims 1 to 7, characterized in that the through-hole is filled with an electrically conductive material.
9. Capacitive sensor film according to any of the preceding claims, characterized in that it comprises one or more protective layers applied to the rear main surface of the reinforcing layer and / or on the front surface of the reinforcing layer.
10. Capacitive sensor film according to any of the preceding claims, characterized in that the sensor conductor is a metal film bonded to the front surface of the reinforcing layer with an adhesive layer or is applied to the front surface of the layer of reinforcement by metallic vapor coating or is an electrically conductive film or pattern comprising a conductive ink.
11. Capacitive sensor film according to any of the preceding claims, characterized in that the area of the protective conductor is selected to protect the sensor conductor and, if present, the maximum protective conductor.
12. 12. Method for manufacturing a capacitive sensor film according to any of the preceding claims, characterized in that it comprises (i) providing a reinforcing layer comprising a rear main surface and a front main surface, (ii) applying a protective conductor to the surface back main of the reinforcement layer, (iii) applying a sensor conductor to the front main surface of the reinforcement layer, and (iv) providing one or more through holes extending through the reinforcement layer in such a manner that the protective conductor, the sensor conductor and optionally the maximum protective conductor can be electrically contacted from a main surface of the laminate. A method according to claim 12, further characterized by comprising applying an electrically insulating film to a main surface of the reinforcing layer, over a through hole, forming a hole in the electrically insulating film in alignment with the through hole and pushing the surrounding portion of the electrically insulating film into the through hole to cover at least part of the wall thereof.