Heater for an automotive vehicle and method of forming same

There is disclosed a heater for an automotive vehicle or other article of manufacture. The heater typically includes a first conductive medium and a second conductive medium disposed upon a carrier. In a preferred embodiment, the first conductive medium includes a first section and a second section that are electrically connected by a second conductive medium. The second conductive medium preferably exhibits a positive thermal coefficient.

FIELD OF THE INVENTION

The present invention relates generally to heaters and more particularly to heaters for use in seats, mirrors, handles or other locations of automotive vehicles, transportation vehicles or other articles of manufacture.

BACKGROUND OF THE INVENTION

For many years, industry has been concerned with designing improved heaters for articles of manufacture such as seats, mirrors or handles of furniture, automotive vehicles or other transportation vehicles. Examples of such heaters are disclosed in U.S. Pat. Nos. 6,084,217, 5,451,747, 5,045,673, 4,931,627 and 4,857,711 all of which are expressly incorporated herein by reference for all purposes.

Many of these prior heater designs suffer from one or more drawbacks. As one example, many prior heater designs were not configured to accommodate systems such as ventilators, which may also be integrated into an article of manufacture such as a seat of an automotive vehicle. As another example, many prior heater designs employed relatively high cost raw materials, high cost manufacturing processes or the like, which caused the heaters to become relatively expensive.

The present invention therefore provides a heater that addresses one or more of the aforementioned drawbacks or addresses other drawbacks that will become more apparent from a reading of the following description.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a heater or heater assembly that includes one or more conductive mediums disposed upon a flexible carrier.

According to one embodiment, the heater includes a first conductive medium disposed upon the carrier and the first conductive medium includes a negative section having a plurality of first extensions and a positive section having a plurality of second extensions. A second conductive medium electrically connects the positive section with the negative section and a plurality of openings extend through the heater.

According to another embodiment, the heater assembly includes a control element or control heater and a main heater disposed upon the flexible carrier. The control element typically includes a first conductive medium formed of a PTC material while the main heater includes a first conductive medium formed of an NTC or CTC material. Preferably, electrical current flows through the control element to and through the main heater such that the control element controls the amount of electrical current flowing through the main heater.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is predicated upon providing an improved heater suitable for integration into a variety of articles of manufacture. For example, the heater may be integrated into or attached to carriers (e.g., members, structures, panels, floors, walls or the like) of various articles of manufacture such as buildings, furniture, transportation vehicles (e.g., boats, trains, airplanes, busses) or the like. Alternatively, the heater may be integrated into or attached to various components of transportation vehicles such as seats, mirrors or mirror assemblies (e.g. rearview mirrors, side view mirrors or the like), gear shifters, panels, footwells, floor mats, cargo or bed liners, windows or other components. The heater is particularly suitable for integration into a seat of an automotive vehicle. More particularly, the heater is suitable of integration with the seat portion, back portion, head rest portion, or a combination thereof of a vehicle seat.

In another automotive application, the present invention may be used in a steering assembly. As such, the heater may be placed on or integrated with various regions of a steering wheel including the hub, wheel, spokes, turn signal or shifter of the steering wheel assembly. Likewise, the heater of the present invention may be located anywhere throughout the vehicle, and most advantageously, with components that generally come in contact with an occupant of the vehicle including arm rest, rear view mirrors, user control interfaces and otherwise.

Outside of the automotive application, it is foreseeable that the present invention may be incorporated into other applications including Bed mattresses, wheel chairs, articles of clothing, or any other object that may come into contact with a person.

Furthermore, the present invention may be used outside of personal comfort applications including: infrared sensing technology, heating electrical or mechanical components or even heating a fluid through a submersion of the heater or an application to the outer walls of a container. Also, the heater may include or be integrated with: an antenna for reception or transmission of radio frequencies; a sensor such as a seat occupant sensor (e.g. for use with an airbag or otherwise), or a sensor for children car seats; a warning device for signaling an alarm when a temperature (internal or otherwise) of the vehicle is undesirably high or low; combinations thereof or the like. In some or all of the previous applications, the heater may be configured with a pressure sensor to determine the presence of an applied force acting on the heater or the sensor.

The heater of the present invention may exhibit one or more advantages as compared to previous heaters. As one example, the heater may control its heat output without employing components such as a controller, a thermostat, a temperature sensor, combinations thereof or the like. Of course, it is contemplated that these components may be included with the heater to assist in controlling or regulating the amount of heat output by the heater. As another advantage, the geometry, sizing, materials and configuration of the heater and its components can assist in forming a more effective heating system within a vehicle seat or other article of manufacture. As an example, a preferred heater may be formed of materials that add flexibility to the heater for assisting in minimizing noise that might otherwise be produced by the heater. As another example, a preferred heater may include one or more contours, openings or cavities for aiding the bending of the heater thereby allowing the heater to conform to contours of an article of manufacture particularly for assisting in attaching the heater to the article.

In one or more alternate embodiments, the heater of the present invention may also be adapted to selectively activate one or more regions of the heater to provide selective heating, to manipulate the heat output generated by the heater or both. In the one or more alternate embodiments, a user can preferably control one or both of the location and intensity of heat provided by the heater of the present invention.

Generally, the heater of the present invention will include one or a combination of the following components:1) a carrier that is preferably configured as a flexible panel;2) a first conductive medium disposed upon the carrier, the first conductive medium preferably including a first section and a second section wherein each section preferably includes a base portion and a plurality of extensions extending from the base portion;3) a second conductive medium for interconnecting the first section to the second section, the second conductive medium preferably including a plurality of resistive strips, which preferably interconnect the plurality of extensions of the first section to the plurality of extensions of the second section wherein the second conductive medium preferably exhibits positive thermal coefficient characteristics.

Optionally, the first conductive medium can include a third section for assisting the heater in providing multiple heat output levels or for allowing selective heating of different locations of the heater.

Referring toFIGS. 1,2and3, there is illustrated the formation of an exemplary heater10in accordance with the present invention. The heater10includes a first conductive medium12and a second conductive medium14disposed upon a carrier18. Generally, the heater10is configured as a flexible panel (i.e., with opposing surfaces and a thickness therebetween) although other shapes or configurations may be employed as well.

For example, while in one embodiment the carrier18may be flexible, it is foreseeable that the carrier may alternatively be rigid or semi-rigid or non existent altogether (discussed in greater detail below). Regardless of the rigidity characteristics of the carrier18, the carrier may be formed in numerous shapes and configuration as desired depending on the application (e.g. seat, seat back, head rest, mirror, steering wheel, or any other article that may be heated to enhance the environment for a user). Moreover, the carrier may include contours for assisting in stress relief particularly when the heater may be subject to stresses from pressure, movement or otherwise.

The carrier18, as illustrated, is configured as panel with opposing surfaces26,28. As seen in the particular embodiment ofFIGS. 1,2and5, the carrier18is substantially elongated and generally rectangular and more preferably is hourglass shaped. As shown, the carrier18has a length (L) and a width (W) and includes an outer peripheral edge22extending substantially continuously about the carrier18substantially defining the shape of the carrier18. The peripheral edge22is shown to include a first lengthwise edge32opposing a second lengthwise edge34.

In the particular embodiment illustrated, the first lengthwise edge32and the second lengthwise edge34have cutouts for helping to form the hourglass shape. For example, the lengthwise edges32,34respectively define a first indentation38and a second indentation40, which respectively define a first concavity44and a second concavity46. The first indentation38generally opposes and is substantially a mirror image of the second indentation40. Both indentations38,40may include one or a plurality of contours48,50,52at least partially defining the cavities44,46. In the particular embodiment illustrated, both indentations38,40include two pair of opposing convex contours48, one pair of opposing concave contours50and one central concave contour52. The carrier18may also include an opening58located between the first and second indentations38,40and which is generally rectangular.

The heater, carrier or both may be shaped as desired and such shape may depend upon the application of the heater. Thus, the carrier or heater shape should not limit the present invention unless otherwise stated. As examples, the heater, carrier or both may include configurations that are circular, oval, elliptical, square, rectangular, geometric, non-geometric, symmetric, or asymmetric, or combinations thereof or the like. Furthermore, the heater, the carrier or both may be preformed (e.g. as planar or contoured) to correspond to an article such as a steering wheel or other article. Alternatively, the heater, the carrier or both may be flexible to allow of such correspondence.

In a preferred embodiment of the present invention, the carrier may be attached to one or more components of an article of manufacture (e.g. a seat, a mirror or the like). Alternatively, a first carrier may provide a release surface, which allows the first and second conductive medium to be transferred to one or more components of the article such that the one or more components become the carrier. This may be achieved according to various techniques such as appliques, dissolvable substrates, removable substrates, or the like. Alternatively, the first and second conductive medium may be placed on one or more of the components of the article itself through printing, spraying, rolling, dabbing, brushing, pouring, or the like, again such that the one or more components become the carrier of the heater.

It is contemplated that the carrier18may be conductive, nonconductive, or partially conductive. This includes electric conductivity, thermal conductivity and diffusion. Also, for attachment purposes, the carrier may be configured to hold and maintain a static charge thereby allowing the carrier to attach itself to a component of an article (e.g. a mirror assembly, a seat or the like), with or without the use of adhesion or fastening techniques.

Alternatively, or in combination with the above, the carrier may further include one or more adhesive materials or layers for attaching the carrier to a component. The adhesive material may be applied to the carrier or, the carrier itself may comprise of adhesive material or have adhesive characteristics. The adhesive may be applied using such techniques as printing, spraying, rolling, dabbing, brushing, pouring or otherwise placed on one or both sides of the carrier.

The carrier18may be formed from various materials including polymeric materials such as plastics, elastomers, thermoplastics, composites or the like. The carrier18may also be formed of woven or non-woven fabric materials, paper materials, impregnated fibers, fibrous materials or the like. The carrier18preferably has a thickness between about 1 micron or less and 1 centimeter or greater, more preferably between about 10 microns and 1 millimeter, still more preferably between about 50 microns and about 200 microns.

One preferred material for the carrier is a polyester film that is commercially available under the tradename MELINEX®, designation number ST505, from the DuPont Company. Another preferred material for the carrier is a spunbound Olefin that is commercially available under the tradename TYVEK® also from the DuPont Company. Still another preferred material for the carrier is a polyester film that is commercially available under the tradename CETUS®, designation number CP2101, from the Cetus Company. Yet another preferred material for the carrier is a nylon polyester or polyether imide that is commercially available under the tradename ULTEM®, designation number 1000 or otherwise, from the General Electric Corporation.

Of course, other types of base substrate material are available for the carrier such as ceramic, glass, polymeric material (e.g. plastic, elastomers, thermoplastic, thermoset, or the like), polyesters, polyethylene, Mylar, woven material (e.g. nylon or cloth), or otherwise.

Preferred carriers have advantageous properties such as strength, flexibility, rigidity, elasticity, dielectric properties, flexibility, a combination thereof or the like depending upon their application. Carriers may also be transparent, opaque, reflective or the like. Preferably, carriers are temperature resistant (e.g. up to 80° C. or more). Furthermore, carriers may exhibit relatively high acceptance to screen printing materials (e.g. polymers).

In preferred embodiments, particularly for seating applications, but for other applications as well, materials used for the carrier of the present invention exhibit an elongation at failure of as much or greater than 15%, more preferably greater that 35%, even more preferably greater than 50% and still more preferably greater than 70%. Also in preferred embodiments, the material used for the carrier of the present invention exhibit a dielectric constant of up to or greater than 0.5, more preferably greater than 1.0 and even more preferably greater than 2.0.

The first conductive medium12may be disposed upon the carrier18in a variety of configurations (e.g., in spaced parallel lines, zig-zags, serpentine, opposing interdigitated lines, etc.). Typically, the first conductive medium12is divided into a first or negative section70and a second or positive section72that are spaced apart from each other upon the carrier18. Preferably, the negative section70does not directly electrically connect with the positive section72. As used herein the terms “positive” and “negative” are only used because one of the sections70,72will be electrically connected to a positive terminal of a power source while the other is electrically connected to a negative terminal as is further described below. It shall be understood that the sections70,72may be interchanged or switched. Preferably, each of the sections70,72respectively includes a base portion74,76and a plurality of extensions80,82extending outwardly from the base portions74,76. As shown, the plurality of extensions80of one section70are spaced apart from the plurality of extensions82of the other section72. Moreover, the plurality of extensions80of the negative section70are spaced apart from each other and the plurality of extensions82of the positive section72are also spaced apart from each other.

In the particular embodiment illustrated, the base portion74of the negative section70extends along substantially the entire first lengthwise edge32of the carrier18while the base portion76of the positive section72extends along substantially the entire second lengthwise edge34of the carrier34. As such both base portions74,76include the same indentations38,40, cavities44,46and contours48,50,52as the lengthwise edges32,34of the carrier18. The base portions74,76also include an opening88extending down the center of the base portions74,76adjacent the indentations38,40, cavities44,46and contours48,50,52.

The extensions80,82are illustrated as elongated fingers that extend from one of the base portions74,76toward the other of the base portions74,76without actually contacting the other of the base portions74,76. As shown, particularly inFIG. 1, wherein only the first conductive medium12is disposed upon the carrier, the extensions80of the negative section70are interdigitated or intermittent with respect to the extensions82of the positive section72thereby forming gaps90between the extensions80,82.

The first conductive medium12may be formed of a variety of materials such as metals, conductive plastics, combinations thereof or the like. While it is contemplated that the first and second sections70,72of the first conductive medium12may be formed of different materials, it is preferred that they be formed of one material. In a preferred embodiment, the first conductive medium12is formed of a polymeric material, which may be printed (e.g., screen printed) upon the carrier18.

As an exemplary embodiment, the material for the first conductive medium12is a polymeric material such as a polymer thick film composition sold under the tradename POLYMER SILVER CONDUCTOR 5025, commercially available from DuPont, 1007 Market Street, Wilmington, Del. 19898. In such an embodiment, the first conductive medium12is typically screen printed upon the carrier18such that the medium12has a thickness of about 2 micrometers to about 4 millimeters, more preferably about 6 micrometers to about 1 millimeter and even more preferably about 12 to about 15 micrometers. Once printed, the conductive medium12is typically exposed to heat for curing. For example the carrier18and medium12may be placed within a box oven and the medium12cured for about 1 to about 10 minutes at a temperature between about 80° C. and about 180° C., more preferably for about 3 to about 8 minutes at a temperature between about 100° C. and about 140° C., still more preferably about 5 to about 6 minutes at a temperature of about 115° C. to about 125° C. As an alternative example, for a reel-to-reel screen printer, the carrier18and medium12may be exposed to temperatures of about 100° C. to about 200° C. for about 20 seconds to about 3 minutes, more preferably temperatures of about 120° C. to about 160° for about 40 seconds to about 2 minutes, still more preferably a temperature of about 140° C. for about one minute for curing the medium12.

While, one or more configurations for the base portions have been discussed, it is contemplated that the base portions of the present invention may be arranged in numerous alternative configurations as well. As such, the base portions may be on opposite, adjacent or same sides of a carrier or may partially or completely overlapping having an interposed insulating material. The shape of the base portions may be geometric or non-geometric. Similarly, the base portion may be symmetrical or asymmetrical in shape. Some possible base portion shapes include: shapes having one or more arcuate boarders (e.g. round, circular, elliptical, oval, helical, combinations thereof or the like), shapes having one or more linear boarders (e.g. rectangular, square, equilateral or the like). It is also contemplated that the base portions may include a variety of both arcuate and linear borders.

In other embodiments, one base portion may be partially or fully enclosed within the other base portion. As an example, a first U-shaped base portion could partially surround a second corresponding U-shaped base portion with interdigitated or otherwise configured extensions extending from the base portions. As another example, a first base portion may be shaped in an enclosed configuration (e.g. as a circle, square, rectangle or the like) such that the second base (which may be of corresponding or non-corresponding shape) portion is substantially enclosed within the first base portion. In either example, the heater may include extensions in any configuration described herein.

While only two base portions are shown, it is foreseeable that additional base portions may be used. Also, the number of electrically positive base portions may or may not be equal to that of the electrically negative base portions.

Accordingly, as with the base portions, the extensions can be arranged in different patterns with respect to the base portions and each other. Some possible patterns include interdigitated serpentine, straight, curved, spiral, rectangular, zigzag, or otherwise. In the embodiment shown inFIG. 2, each first extension from the first base portion is separated from the next closest first extension by no more than one second extension from the second base portions. However, it is contemplated that a first extension from the first base portion may be separated from the next closest first extension by two or more second extensions from the second base portion. In such an embodiment, it is preferably although not required that the second conductive medium interconnects only first extensions from the first base portion with second extensions from the second base portion.

Additionally, it is contemplated that two sections of the first conductive medium may form an overlapping relationship in order to create a more desirable circuit for selective heat generation of the heater. For example, a first section of the first conductive medium may be configured in an overlapping relationship with a second section. In such an instance, an insulating or nonconducting material typically interposes the first and second sections, to prevent currents from traveling directly from one section to another section without passing through the second conductive medium. Of course, direct passage of current between sections may be desirable in some instances (e.g. such that current only passes through a portion of the second conductive medium). However, the first and second sections may alternatively be interposed by the second conductive medium, or otherwise to provide a heating circuit. For example, a second conductive medium may be sandwiched between a portion of the first and second section. As such, when a current travels from the first and second section, it is possible for the second conductive to generate heat therebetween.

This overlapping relationship of the different sections of the first conductive medium provides the ability to form more intricate circuit designs. One advantage of having more intricate circuits is the ability to generate multiple heat outputs from a single heating unit. Another advantage is the ability to provide a heating unit having more then one heating regions that are selectively activated.

In any of the possible base portion configurations, the width and thickness of the portion may be consistent throughout, variable, or progressively narrowing or expanding. Likewise, the width and thickness of an extension from the first or second base portions may be consistent, variable, or progressively narrowing or expanding. Furthermore, the thickness, length and width of the first and second extensions may vary throughout the heater. Moreover, the extensions may be parallel, skew, nonparallel or the like relative to each other, the base portions, the extensions from the other base portion or relative to the second conductive medium.

As with the base portions, the extensions from either of the base portions may overlap each other wherein nonconductive medium is placed between the overlapped regions.

The material of the base portion and the extensions may be the same or different material depending on the application. Moreover, the extensions may be interconnected by the second conductive medium such that the base portions are connected.

Alternatively, it is contemplated that there are no extensions and the base portions are in direct contact with a conductive medium. Examples of this configuration includes the overlapping of the base portions having an interposed conductive medium. In another example, the base portions may be configured adjacently, or otherwise, having a conductive material interposed. In the above examples, the application of more than two base portions may be desired.

Referring toFIGS. 2 and 3, the second conductive medium14may be disposed upon the carrier18in a variety of configurations. The second conductive medium14may be continuous, intermittent, planar, geometric, contoured, combinations thereof or the like. Preferably, the second conductive medium14electrically connects the positive section72of the first conductive medium12with the negative section70of the first conductive medium12.

In the exemplary embodiment illustrated inFIG. 2, the second conductive medium14includes a plurality of strips94, which are shown as separate from each other, but which may be interconnected. Each of the strips94is elongated and extends with and/or preferably parallel to the extensions80,82of the first conductive medium12and each strip94electrically connects an extension80of the negative section70with an extension82of the positive section72. As shown, each of the strips94overlaps and directly contacts one extension80of the negative section70and one extension82of the positive section.72.

It is also for preferred, but not necessarily required, that each of the plurality of strips94have substantially the same size and shape and that the strips94be substantially uniformly spaced apart from each other. Moreover, it is preferable for the strips94to have uniform densities compared to each other and throughout each strip94. In this manner, the heater10can typically produce a more uniform heat intensity along the length and/or width of the heater10.

The second conductive medium14may be formed of a variety of materials including metal, plastics or combinations thereof. Preferably, the material exhibits relatively high positive thermal coefficient (PTC) as will be discussed further below. While it is contemplated that the strips94may be formed of different materials, it is preferred that they be formed of one material. In a preferred embodiment, the second conductive medium14is formed of a polymeric material, which may be printed (e.g., screen printed) upon the carrier18.

In an exemplary embodiment, the material for the second conductive medium14may be a polymeric material such as a polymer thick film composition sold under the tradename PTC CARBON RESISTOR 7282, commercially available from DuPont, 1007 Market Street, Wilmington, Del. 19898. In such an embodiment, the second conductive medium14is typically screen printed upon the carrier18such that the medium14has a thickness of about 1 micrometer to about 1 millimeter, more preferably about 3 micrometers to about 10 micrometers and even more preferably about 6 to about 8 micrometers. Alternate printing methods include silk screen printing, ink jet printing or the like. Once printed, the conductive medium14is typically exposed to heat for curing. For example, the carrier18and medium14may be placed within a box oven and cured for about 2 to about 30 minutes at a temperature between about 90° C. and about 200° C., more preferably about 5 to about 15 minutes at a temperature of about 110° C. to about 150° C., still more preferably about 10 minutes at temperature of about 130° C. As another example, for a belt drier, the carrier and medium14may be exposed to temperatures of about 110° C. to about 210° C. for about 1 minute to about 20 minutes, more preferably temperatures of about 130° C. to about 170° for about 2 minutes to about 10 minutes, still more preferably a temperature of about 150° C. for about 3 to about 5 minutes.

Other conductive mediums used in the above printing methods include aqueous polymers including conductive fillers (e.g. conductive metal powder, metallic oxide, silver, copper or otherwise), resistive fillers (e.g. carbon or otherwise), films (e.g. polyurethane, UV curable Polymeric dielectric composition, thermosetting resins (e.g. epoxies, phenol resins, or the like), or otherwise), ethylene vinyl acetate co-polymer resin having black carbon or a combination thereof. Preferably, the ink is impermeable to light and may include one or more of the following binders: resin-based acrylic ink, borosilicate lead-glass, thermosetting resins (e.g. epoxy, phenol, melamine resin), or conductive powder.

The second conductive medium may be applied in a variety of patterns alternative to that which is shown. In one embodiment, the conductive medium may emulate (e.g. extend parallel) the pattern of the first and second base portion. Preferably, the conductive medium is at least partially interposed between the extensions of the first and second base portions. When provided as strips or otherwise, the conductive material may be parallel, angled, skew, perpendicular, serpentine with respect to the extensions of the base portions or the base portions themselves. Also the pattern of the second conductive medium may be comprised of concentric or non-concentric geometric configurations, e.g. circles, squares, oval, or otherwise. Furthermore, the second conductive medium may be randomly or systematically place between extension of the base portions, or between the base portions, and may comprise a plurality of strips having cut out portions. The strips of the conductive material may also be sectioned or broken into pieces.

While preferred material for the first and second conductive mediums have been disclosed, it is contemplated that other materials may be employed as layers or otherwise for providing part or all of the first and second conductive mediums. Examples of these materials include: foil tape, transfer paper, strips sheets, sleeves, strands of electrically conductive thread, wire, deposited metal, plated material, sewn material or otherwise. Other materials include: metals (e.g. aluminum, chromium, nichrome, or otherwise), carbon, film, foam (either thermally or non thermally conductive) (e.g. Comfortem® by foam international), electrically conductive woven fabric having a conductive coating such as silver, polymeric material (applied as a film or printed, discussed more below).

The heater10of the present invention also typically includes one or more (e.g. a pair of) electrical connections100,102. Preferably, each of the connections100,102is respectively in electric communication with one of the base portions74,76of the negative and positive sections70,72.

It shall be understood by those skilled in the art that a variety of electrical connections may be employed. In the particular embodiment ofFIG. 2, each of the electrical connections100,102includes a wire104(e.g., a coated copper conductive wire) having an end106that is attached (e.g. soldered) to a foil patch108(e.g., of electrically conductive tape) and the patch108with the end106is attached (e.g., adhered) to one of the base portions74,76. In an alternative exemplary embodiment, and referring toFIG. 2A, an electrical connection110is employed wherein a member112includes a rivet114connected to one of the base portions74and an eyelet116connected to a wire120.

Advantageously, the heater of the present invention may be formed with only one or two electrical connections for providing a current through the base portions, the extension, the second conductive medium (e.g. the strips) or a combination thereof. Of course, additional connections may be used if desired or needed. As an added value, the heater10can be formed with the entirety of the first and second conductors supported by the single carrier18without requiring additional layers for supporting the conductors. Of course, additional layers may be used if needed or desired.

The electrical connections may be located on the same side of the carrier. Alternatively, the electrical connections may be located on opposite or adjacent sides of the carrier. Also, the electrical connections may be diagonally opposite each other on the carrier. Thus, the electrical connections may be situated such that the summation of the electrical paths between adjacent portions of the extension are substantially equivalent or substantially non equivalent.

The electrical connections may be integrated into a single unit, having both positive and negative leads, or may be separated into two or more connections. Furthermore, the electrical connections may be integrated into a single extension or “tail”, or multiple “tails”, used to electrically connect the heater to a power or energy source (e.g. a battery).

The heater of the present invention may be capable of operating at one or multiple heat outputs. Various techniques may be used for producing multiple heat outputs. For example, two or more circuits may be configured to operate at different output levels and may be disposed or printed on one, two or more carriers. Alternatively, referring to any of the embodiments contained herein, two or more sets of electrical connections could deliver different energy levels (e.g. voltages) to one, two or more circuits printed onto one, two or more carriers. Moreover, one, two or more electrical connections may be configured for delivering different output levels for delivering different output levels to the above configured heaters.

The present invention may further comprise one or more control safety features including: thermostat, control module with Negative Temperature Coefficient (NTC) resistor, Positive Temperature Coefficient fuse or some other temperature sensing device. Also, a Constant Temperature Coefficient (CTC) may be used for eliminating the effect of the temperature of the heating element on the amount of heat generated by the heating element. The above features can allow the system to shut down upon sensing of excessive temperatures or a short in the system.

Also, the present invention may be configured with one or more switches (e.g. a latch switch or momentary switch), for applying a current to the heater of the present invention. For example, a control module may be used in conjunction with a momentary switch for turning the heating device on and off. Alternatively, a switch (e.g. an on/off switch) may be used to physically connect and/or disconnect a circuit that includes the heater with an energy source. Other switches that may be used includes a voltage control potentiometer, multiple position switch for allowing choice of temperature settings (e.g. high-low-off), multi-pole switch or otherwise.

The heater of the present invention is electrically connected to an energy source to generate a current through the heater to produce heat. The energy source may provide an alternating current, a direct current, or a combination thereof. In an automotive application, preferably the heater is electrically connected to an automotive energy supply, (e.g. 12 volt battery). Alternatively, or additionally, the heater may be connected to the alternator, control module or other electrical components in the vehicle.

In any of the discussed embodiments, includingFIG. 3, an insulation layer130may be laminated over the conductive mediums12,14of the heater10. The insulation layer130may be formed of fleece, gauze or the like and may be fastened to the carrier18via adhesive or otherwise.

WhileFIG. 3has been illustrated with an insulation layer130, it is contemplated that the heater10may advantageously be formed without any such additional insulation layer130. Moreover, it is contemplated that the insulation layer130may be provided by the seat (e.g., as part of a trim layer) and that the insulation material may not be specifically adhered or otherwise attached to the heater10. The application of the insulating material is numerous and at a minimum includes the methods used below in applying the protective coating.

As another option, the first conductive medium12, the second conductive medium14or both may be fully or partially covered with a protective coating. In a preferred embodiment, the first and second conductive mediums12,14are coated with a protective dielectric coating formed of a polymeric dielectric composition. Preferably, the coating is curable (e.g., UV curable), solvent less or a combination thereof. The coating may be applied to the conductive mediums12,14by several methods such as printing, spraying, rolling, dabbing, brushing, pouring or the like, but is preferably screen printed upon the mediums12,14. The coating may be up to 5 millimeters thick or greater and is preferably between about 10 microns and about 4 millimeters thick, more preferably between about 100 microns and about 3 millimeters thick (e.g., between about 1 to about 1.2 millimeters thick). In a preferred embodiment, the protective layer has electrical, or thermal, insulating characteristics.

Materials available for both the insulating layer and protective layer include the same materials used for the carrier. Additional layers that may be used for the insulating and protective layers having di-electric properties include: paper, film (e.g. polyurethane, UV curable polymeric dielectric composition, thermosetting resins or otherwise), vinyl sheet, fleece, gauze, flexible sheets (e.g. elastomeric, polyester terephthalate, polycarbonates, or otherwise), foam (e.g. thermally conductive, non-thermally conductive, polyurethane, neoprene, or otherwise), glass or the like. However, a protective layer may be conductive in certain layered configurations.

In any of the embodiment of the present invention, it is contemplated that an adhesive is disposed on either side of the carrier or conductive mediums prior to the heater of the present invention being applied to a specific article (e.g. a seat cover, mirror or otherwise). It is also contemplated that adhesives may be on both sides of the carrier to adhere to one or more additional components associated with the heater such as a protective layer or otherwise. Also, it is contemplated that no adhesives are used in the present invention but instead static electricity or some other self attachment is used to mount or fix the heater to a specified region of the article.

Vehicle Seat and Mirror Applications

As previously discussed, the heater10of the present invention may be integrated into various articles of manufacture. Referring specifically toFIGS. 4 and 5, as an example, the heater10is shown integrated into a seat140of a vehicle. The heater10of the present invention may be located in various portions of an automotive vehicle seat such as a support portion, a backrest portion, a shoulder support portion or a headrest. The heater may be located between the trim of the seat and the foam cushioning of the seat. The heater may also be integrated into the trim of the seat, the foam cushioning of the seat or both.

Referring toFIG. 4, the seat140is illustrated with the heater10ofFIG. 2 and 3positioned in both a seat backrest component142and a seat support component144. In the embodiment illustrated, each component142,144of the seat140includes a trim layer146and a foam cushion148and each of the heaters10is positioned substantially between the foam cushion148and trim layer146. Preferably, each heater10is fastened to the seat140(e.g., the trim layer146, the cushion148or both) for maintaining the heater10stationary relative to the seat140. It is also contemplated that tape150(e.g., two-way tape), as shown inFIG. 3, or other fasteners or adhesives may be employed to fasten the heater10to the seat140and particularly the foam cushion148.

In a highly preferred embodiment shown inFIG. 5, a central portion160of the heater10is tied down atop a foam cushion162of a seat with the central portion160extending at least partially into a cavity164(e.g., a trench) of the cushion162. As shown, tie strings170extend through the opening58over the top of the central portion160of the heater10to tie the heater10down. Advantageously, the contours48,50,52of the carrier18and the first conductive medium12curve about foam cushion162at the cavity164when the central portion160of the heater10is extended into the cushion162thereby relieving stress that might otherwise be placed upon the first conductive medium12and particularly the base portions74,76of the first conductive medium12. Moreover, the opening58also serves to relieve stress as the central portion160of the heater10is extended into the cushion. While the contours48,50,52and opening58have been employed for relieving stress during application to a foam cushion162, it should be understood that the contours48,50,52and opening58may also assist in relieving stress wherever the heater10curves about an object to which it is applied.

In one alternate embodiment, the present invention is integrated with a mirror assembly. In such an embodiment, the shape of the heater, carrier or both is likely to change to the corresponding shape of the mirror assembly. An example of such an embodiment is shown inFIG. 6, wherein the heater10is configured with a carrier18, a first conductive medium12and a second conductive medium14configured in a manner similar for those previously discussed.

The first conductive medium12is preferably configured with a first base portion74and a second base portion76having associated first and second oppositely charged electrical connectors100,102respectively. Preferably, the shape of the first and second base portions74,76, the carrier18or both conform to the shape of the mirror12, backing or both. Furthermore, it is contemplated that the first and second base portions74,76may have varying widths as they extend along the carrier14.

Extending from the first and second base portions74,76are a plurality of interdigitted first and second extensions80,82having varying lengths (e.g., becoming progressively larger or smaller) according to the contours of the first and second base portions74,76and the contours of the mirror. Preferably the extensions80,82are parallel with respect to each other, however, other configurations are contemplated as disclosed herein. Also, other patterns are contemplated as disclosed herein.

Preferably, each of the sections70,72respectively includes a base portion74,76and a plurality of extensions80,82extending outwardly from the base portions74,76. As shown, the plurality of extensions80of one section70are spaced apart from the plurality of extensions82of the other section72. Moreover, the plurality of extensions80of the negative section70are spaced apart from each other and the plurality of extensions82of the positive section72are also spaced apart from each other.

Alternatively in another embodiment, referring toFIG. 7, the heater10of the present invention may be applied to, or incorporated with, a mirror assembly180(e.g. side mirror, rear view mirror, or the like). The mirror assembly180is typically configured with a mirror182, a mirror backing184and a housing186, although each component is not necessarily required. In the illustrated embodiment, the heater10includes a carrier18that is attached to the mirror182, the backing184or both. Alternatively, however, it is contemplated that the mirror182or backing184may be the carrier for the conductive mediums of the heater10.

The carrier18may be applied to (e.g. attached to) the mirror182, the backing184or both using a variety of techniques. In one embodiment, the attachment of the heater10to the mirror182or backing184may be accomplished with adhesives, fasteners, combinations thereof or the like. Alternatively, the heater10may be attached without the use of adhesives or fasteners. For example, the heater10may be statically adhered to the mirror182or backing184. As another alternative, the carrier18may be composed of a material having adhesive characteristics for adhering the heater10to the mirror assembly180.

Alternatively or additionally, it is contemplated that the mirror assembly may be configured for securing the heater10to itself. For example, the mirror182, the backing184or both may include one or more recesses for receiving and securing the heater10thereto. As another example, the heater10may be sandwiched and secured between the mirror182and the backing184. Moreover, the mirror assembly180may be configured with integral fasteners (e.g. snap-fits) for securing the heater10.

In addition to the first conductive medium12and the second conductive medium14, the electrical connectors100,102may be directly attached to the mirror182, the backing184or both. Advantageously, any portion of the heater10not disposed or incorporated on a portion of the mirror assembly180, may be adhered or fastened to the mirror assembly180using any of the techniques described herein. For example, the mirror182or backing184may be coated with the second conductive medium14while the first conductive12medium may be placed over the second conductive14according to a different technique. Further, it is contemplated that the mirror182contacts either the first conductive medium, the second conductive medium or both. Optionally however, one or more additional layers (e.g. insulating, protective, otherwise or a combination thereof) as described herein may be place over the first conductive medium12as desired.

In operation, the heater10can operate to heat the mirror182in substantially the same manner as the heater can be used to heat a seat. Advantageously, the heater can assist in removing water in the form of condensation, frost or otherwise from the mirror182.

Operation

In operation, and referring toFIGS. 2 and 4one electrical connection102is connected to a positive terminal of an electrical power source (not shown) and the other connection100is connected to a negative terminal of the electrical power source. In turn, when the power source provides electrical energy to the heater10, an electrical current flows from one electrical connection100to the base portion74of the negative section70of the first conductive medium12. The electricity then flows to the extensions80of the negative section70and through the strips94of the second conductive medium14to the extensions82of the positive section72of the first conductive medium12. Thereafter, the electricity flows to and through the base portion76of the positive section72of the first conductive medium12and out of the heater10through the electrical connection102. Due to the resistance of the second conductive medium14, the strips94elevate in temperature thereby heating the seat10, and particularly the trim146of the seat140. Advantageously, the strips94of the second conductive medium14exhibit positive thermal coefficient characterization such that the strips94are self-limiting with regard to how warm they will become. More specifically, for a particular voltage applied to the second conductive medium14, the resistance of the second conductive medium14will rise, which in turn, causes the current flowing through the second conductive medium14to become lower until an equilibrium is attained. As will be recognized by the skilled artisan, various variables such as the voltage applied to the heater, the composition of the second conductive medium14, the size and configuration of the second conductive medium14and others may be varied such that the equilibrium for the medium14is achieved at desired heat output. It is also contemplated that, after use, the resistance of the second conductive medium may shift (e.g., upwardly shift) between about 15% and about 25%. If such is the case, it is typically desirable to design the configuration of the second conductive medium to account for the shift while still producing the preferred heat output.

In preferred embodiments, the distance between the positive section of the first conductive medium and the negative section of the first conductive medium (i.e., the distance that the second conductive medium spans to interconnect the sections) may be set to assist in controlling the temperature of the second conductive medium, the heater or both during operation. In the preferred illustrated embodiment, the extensions82of the positive section72are typically separated from the extensions80of the negative section70by a distance of about 0.5 millimeter to about 1 centimeter, more preferably about 1.5 millimeters to about 5 millimeters, still more preferably about 3 millimeters. Also in the preferred embodiment, the second conductive medium14, the heater10or both reach a temperature between about 0.0° C. and about 100° C., more preferably between about 25° C. and about 80° C., still more preferably between about 50° C. and about 70° C.

In addition to the previous embodiments, it is also contemplated within the scope of the present invention that the heater can include a first conductive medium having at least three sections, which are interposed by a second conductive medium. In such an embodiment all three sections of the first conductive medium can be electrically connected through the second conductive medium thereby providing the ability to form multiple heating circuits. For example, one or more circuits may be created between a first and second section, the first and third sections, the second and third section or between all three sections. Also, with the use of a first conductive medium having at least three sections, numerous circuits may be selectively generated between any two sections having an interposed second conductive medium. As such, preferred heating regions may be generated.

In this alternate configuration, one section of the first conductive medium is connected to a first or positive terminal and another section is connected to a second or negative terminal of a power supply for forming a first heating circuit. By connecting yet another section of the first conductive medium to the positive or negative terminal of a power supply, a second heating circuit may be generated between this section and any other section (e.g., the aforementioned sections or additional sections) connected to an oppositely charged terminal.

Advantageously, a switching device, as disclosed herein, may be used for selectively and electrically connecting the sections of the first conductive medium to the positive or negative terminal of a power supply. Moreover, it should be understood that the materials discussed for the carrier, the first and second conductive mediums may also be appropriately employed in the following embodiments and may be applied as previously discussed. It is also contemplated that the following embodiments may include an insulation layer that may be formed of the same materials and applied to the carrier, the conductive medium or a combination thereof as described in the previous embodiments. Examples of these types of configurations are disclosed in U.S. patent application Ser. No. 10/715,160, filed Nov. 17, 2003, titled Heater for an Automotive Vehicle and Method of Forming Same, which is expressly incorporated herein by reference for all purposes.

Under various circumstances, but particularly when a vehicle seat is ventilated, it can be desirable for the heater to be breathable. As used herein, the term breathable means that the heater allows fluid (e.g., air) to flow through it (e.g., through the carrier of the heater). The heater may be made breathable by using a fluid permeable carrier such as a substrate formed of multiple strands of material that are combined (e.g., woven together) to form a fabric panel. Exemplary materials for the strands can include natural fibers, synthetic fibers, polymeric strands (e.g., polyamide strands, polyester strands, combinations thereof or the like).

When a carrier is formed of a substantially fluid (e.g., air) impermeable material, a plurality of openings (e.g., at least 2, 4, 10, 20, 50 or more openings) may be formed in the carrier to make the heater, the carrier or both breathable. The openings may be through-holes, slots, slits, combinations thereof or the like and may be shaped and sized as needed to provide the desired amount of breathability and can additionally increase flexibility. Such openings may be formed in any of the substrates mentioned herein for carriers and may be formed by cutting, punching, slicing, drilling, combinations thereof or the like. Alternatively, the carrier may be formed (e.g., molded) according to a process that automatically creates the opening in the carrier. For example, a liquid polymeric material may be shaped in a mold having multiple protrusions such that the polymeric material upon solidifying forms a carrier with multiple openings corresponding to the multiple protrusions. Generally, openings in the heater may extend through the carrier only or may extend through the carrier and any of the other portions of the heater including, but not limited to, the conductive mediums, the sections, the base portions, the extensions, the strips, combinations thereof or the like.

Referring toFIGS. 8,8A and8B, there is illustrated one exemplary breathable heater400formed in accordance with an aspect of the present invention. As can be seen, the heater400includes a carrier402with a first conductive medium406and a second conductive medium408disposed thereon. The first conductive medium406is comprised of a first section412and a second section414which are spatially separated from each other, but electrically interconnected by the second conductive medium408.

In the particular embodiment illustrated, the first section412and second section414each respectively include a base portion420,422and multiple extensions426,428extending from the base portions420,422. As shown, the extensions426of the first section412are interdigitated with the extensions428of the second section414. Also, as shown, the second conductive medium408is divided into a plurality of masses shown as strips432. Preferably, although not required, the extensions426,428and the strips432extend substantially parallel to each other.

In the embodiment shown, the extensions426,428, are divided into sets436(e.g., at least 2, 4, 8, 10 or more sets), which are specially separated from each other. Each of the sets includes at least one extension426of the first section412, at least one extension428of the second section414and at least one mass or strip432of the second conductive medium408. Preferably, the at least one strip432electrically interconnects (e.g., physically overlaps) the at least one extension426of the first section412and the at least one extension428of the second section414for each set436. As can be seen, each set436is separated from an adjacent set436by an open space440. In other words, each set436creates a substantially covered strip444of surface area of the carrier402and each covered strip444of surface area of the carrier402is separated by an uncovered strip448of surface area of the carrier402. Preferably, although not required, the uncovered strips448are substantially parallel to the covered strips444and each of the strips444,448extends from adjacent one base portion420to adjacent the other base portion422.

The heater400also includes openings, which in the embodiment illustrated, include one or more sets (e.g., at least 2, 4, 8, 10 or more sets) of first openings452and one or more (e.g., at least 2, 4, 8, 10 or more sets) sets of second openings454. The first openings452extend entirely through the carrier402and particularly through the uncovered strips448of surface area of the carrier402. The second openings454also extend entirely through the carrier402and particularly through the covered strips444of surface area of the carrier402. The second openings454also extend through the strips432of the second conductive medium408.

While the first openings452and second openings454of the heater400are shown as extending through particular portions of the heater400, it should be understood, as previously suggested, that the openings may additionally or alternatively through any chosen portion of a heater formed in accordance with the present invention. It should further be understood that such opening may extend through any of the heaters discussed or described herein. Furthermore, if the heater includes an insulation layer disposed over the first and second conductive medium, the openings can extend through that insulation or protective layer as well.

It should be understood that any of the heater designs disclosed herein may made breathable by forming openings in the heaters and/or by otherwise modifying the heaters as described above and with respect toFIG. 10. Advantageously, the breathable heaters can be employed in conjunction with seat ventilation systems such as those described in the following U.S. patent applications: Ser. No. 10/434,890, titled Automotive Vehicle Seat Insert, filed May 9, 2003, and Ser. No. 10/463,052, titled Automotive Vehicle Seating Comfort System, filed Jun. 17, 2003, both of which are incorporated herein by reference for all purposes. Thus, it is contemplated that the heaters and particularly the breathable heaters of the present invention may be employed in conjunction with a seat insert that is designed to move air through a seat cover of a vehicle seat. It is also contemplated that the heaters can overlay a seat cushion that includes an opening therethrough wherein an air mover (e.g. blower) or thermoelectric air mover moves air through the opening to, in turn, move air through a seat cover. Accordingly these ventilation systems can move air through the heaters, the heat assemblies, the carriers or a combination thereof for the present invention.

In another additional or alternative embodiment of the present invention, it is contemplated that any of the heaters discussed herein may be adapted to include slits extending across a substantial portion of a length, width, other dimension or combinations thereof of the substrate or carrier of the heater. Advantageously, when employed in vehicle seats, such slits can provide the heater with increased flexibility and can relieve stresses or strains that might otherwise be placed upon the conductive materials of the heater. Typically such slits extend only through the carrier or the heaters, although they can extend through the conductive materials. It is also typical for such slits to extend through portions of the carrier that are not covered or coated by any of the conductive materials, although not required.

Referring toFIG. 9, the heater400ofFIG. 8has been modified to include slits462extending across a substantial portion (e.g., 30%, 60%, 70% or greater) of a dimension (e.g., a width) of the heater400. It should be understood that the slits can extend substantially continuously across the dimension of the heater or can extend intermittently (e.g., as a group of separate slits) extending across the dimension. As shown, the slits462extend through the carrier402and extend continuously across the width at, through or along the uncovered strips448. The strips462are also shown as extending substantially parallel to the extensions426,428, the strips444or a combination thereof.

It will be understood that the components of the heater400ofFIGS. 8 and 9including, without limitation, the first conductive medium406, the second conductive medium408, the extensions426,428, the base portions420,422, the carrier402, the connections or other components may be formed of any of the materials discussed above with respect to such components in other heater embodiments.

In yet another additional or alternative embodiment, it is contemplated that the heater may include a resistive element in series or in parallel with a heater for assisting in controlling the flow of electrical current through the heater. According to this alternative embodiment, it is contemplated that the resistive element may be provided in a variety of configurations. However, in one preferred embodiment, the resistive element is provided as a control element (e.g., a control heater) that is disposed upon the carrier in a manner similar to a main heater.

Referring toFIGS. 10 and 10A, there is illustrated a heater assembly450with a control heater452and a main heater454disposed upon a carrier456. In the particular embodiment shown, the main heater454is located on a body portion460of the carrier456and the control heater452is disposed upon an extension462of the carrier456wherein the extension462extends away from the body portion460. Although not required, the control heater452typically covers less surface area of the carrier456than the main heater454. In a preferred embodiment, the control heater452covers a surface area that is less than half, more preferably less than a quarter and still more preferably less than an eighth of a surface area covered by the main heater454.

Both the control heater452and the main heater454respectively include first conductive mediums468,470and second conductive mediums474,478. The first conductive mediums468,470are respectively comprised of first sections482,484and second sections488,490which are spatially separated from each other, but electrically interconnected by the second conductive mediums474,478.

In the particular embodiment illustrated, the first sections482,484and second sections488,490respectively include base portions500and multiple extensions502extending from the base portions500. As shown, the extensions502of the first sections482,484are interdigitated with the extensions502of the second sections488,490. Also, as shown, the second conductive mediums474,478are each divided into a plurality of masses shown as strips506. Preferably, although not required, the extensions502and the strips506extend substantially parallel to each other.

The heater assembly450also includes at least two electrical connections510,512, which are electrically connected to an electrical power source (e.g., a car battery). As shown, one connection510is negative (e.g., connects to a negative terminal of the power source) and the other connection512is positive (e.g., connects to a positive terminal of the power source). Also, as shown, the

The heater assembly450also includes at least one connector520electrically connecting the first conductive medium468of the control heater452to the first conductive medium470of the main heater454. In the particular embodiment shown, the connector520is an elongated buss bar that extends from the base portion500of the second section488of the control heater452to the base portion500of the first section490of the main heater454. In the embodiment shown, the connector520is formed of that same material as the first conductive medium of the control heater452, the main heater454or both. It is contemplated, however, that the connector520may connect various different components of the heater assembly450and may be formed of a variety of material such as electrical wires and electrical connections.

It will be understood that the components of the heater assembly450ofFIGS. 10 and 10Aincluding, without limitation, the first conductive mediums468,470, the second conductive mediums474,478, the extensions502, the base portions500, the carrier456, the connections510,512or other components may be formed of any of the materials discussed above with respect to such components in other heater embodiments.

In operation, electrical current preferably flows to and through the first electrical connection510, the control heater452then the connector520, then the main heater454and then the second electrical connection512. In the control heater452shown, the electrical current flows from the base portion500of the first section482to the extensions502of the first section482, through the second conductive medium479, to the extensions502of the second section488and then to the base portion500of the second section488. The current then flows through the connector520to and through the base portion500of the second section490of the main heater454, then to and through the extensions502of the second section490followed by flowing through the second conductive medium506to the extensions502of the first section484. The current then flows to and through the base portion500of the first section484and then out through the second electrical connection512.

Preferably, although not necessarily required, the second conductive medium474of the control heater452is formed of a PTC material such that, as current flows through the control heater452and the temperature of the second conductive medium474gets higher, the resistance of the second conductive medium also gets higher until an equilibrium electrical current flow and an equilibrium temperature and/or heat output is achieved for the control heater452for any voltage supplied by the power source.

In turn, that equilibrium current then flows to the main heater454. The second conductive medium478of the main heater454then produces a temperature or heat output that reflects the equilibrium current delivered to it. In this manner, the control heater452controls the current that is provided to the main heater454and therefore also at least partially controls the heat output of the main heater454.

It will be understood that, by employing such a control heater452, the current delivered to the main heater454is controlled. Thus, the second conductive medium478of the main heater454need not be a PTC material although it could be. The second conductive medium could be a negative temperature coefficient (NTC) material or a constant temperature coefficient (CTC) material or both. Advantageously, such alternative materials can be less expensive, have greater durability or the like.

It should be understood that, when the heater assembly450is applied to a seat of an automotive vehicle, the heater assembly450can be placed upon a seat such that the main heater454spans the main seating area of the seat while the control heater452can be located away from such main seating area.

It is even still further contemplated that any of the heaters discussed herein can have a sensor pad incorporated therewith. Typically, the sensor pad is designed to sense or activate when an individual is present or when an individual is not present. The sensor is also typically in signaling communication with the heater for activating the heater when the individual is present and de-activating the heater when the individual is not present.

InFIG. 11, there is illustrated a heater600, which may be any of the heaters disclosed herein and may include any of the features or materials of any of those heaters. The heater includes a sensor pad602, which is particularly useful in conjunction with seat heaters (e.g., vehicle seat heaters), but which may be used with other heaters as well, for detecting whether an individual is seated in a vehicle seat. The sensor pad is typically located above or below the heater and can be attached to (e.g., adhesively secured to) the heater or separate from the heater.

Referring toFIG. 11, the sensor pad602typically includes one or more first electrically conductive elements606separated from one or more second electrically conductive elements608by one or more gaps612. The first element[s]606and the second element[s]608are typically in communication with an electrical energy source (e.g., via busses, wires or the like), but the first element[s]606are typically in communication separately from the second element[s]608. When an individual sits down in the seat, the gap[s]612are typically closed and the first electrically conductive element[s]606contact the second conductive element[s]608for closing a circuit that includes the energy source such that electrical current can flow between the first element[s]606and second element[s]608.

Upon closing of the circuit, the sensor pad602will typically send an electrical signal via a buss, wire or other electrical element signaling an on condition for the heater600. The signal may be sent to a controller and then the controller may command electrical current to flow to the heater600for activating the heater600. Alternatively, upon receipt of the signal, the controller may await a signal from another source (e.g., a switch operated by an individual) before commanding current to the heater600. It is also possible for the sensor pad602to be in direct electrical communication with the heater600(e.g., part of the same circuit) such that, when the circuit is closed, electrical current automatically flows to the heater600.

In the embodiment shown inFIG. 11, the first conductive elements606are attached to or disposed upon a first layer620of material and the second conductive elements608are attached to or disposed upon a second layer622of material and a third layer624of material is intermediate the first and second layers620,622. As shown, the first conductive elements606generally oppose the second conductive elements608and the intermediate layer624has several holes628that define the gaps612between the elements606,608. When an individual sits in the seat, the intermediate layer624is typically compressed by a force (indicated with arrow626) to allow the elements606,608to contact each other by having the first elements606, the second elements608or both travel partially or entirely through the holes628.

It should be understood that the conductive elements may be formed of any of the conductive materials discussed herein or others and may be printed upon or otherwise disposed upon the layers using a variety techniques including those discussed herein and others. Moreover, the layers may be formed of any of the materials discussed in relation to the carriers of the heaters of the present invention.

It is additionally contemplated that the sensor pad may be configured to provide two, three or more signals depending upon conditions sensed such as the weight of a person in the seat. InFIG. 11A, a sensor pad640is shown to have an intermediate layer642of varying thicknesses644,646,648. In such an embodiment, greater force or weight is needed to contact conductive elements adjacent a greater thickness644as opposed to contacting conductive elements adjacent a smaller thickness648. As such, the signal sent by the sensor pad640can be varied depending on the weight of an individual in the seat. Such signal can be employed to assist in controlling air bag deployment or other systems.

Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. Plural structural components can be provided by a single integrated structure. Alternatively, a single integrated structure might be divided into separate plural components. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention.

The preferred embodiment of the present invention has been disclosed. A person of ordinary skill in the art would realize however, that certain modifications would come within the teachings of this invention. Therefore, the following claims should be studied to determine the true scope and content of the invention.