Abstract:
A sensing apparatus having a sensor formed in a monolithic semiconductor substrate and oriented orthogonally to a signal conditioner is provided. The sensor generates a sensing signal in response to a predetermined physical stimulus. A signal conditioner electrically connected and responsive to the sensor conditions the sensing signal. The signal conditioner, moreover, is preferably formed in the same semiconductor substrate and, more preferably is oriented at a right angle relative so as to be orthogonal to the sensor to thereby enhance the compactness of the sensing apparatus.

Description:
RELATED APPLICATIONS  
       [0001]    This application claims priority to Provisional Application Ser. No. 60/288,312, filed May 2, 2001, and incorporates by reference the disclosures of Provisional Application Ser. No. 60/288,282 filed May 2, 2001, Provisional Application Ser. No. 60/288,313 filed May 2, 2001, Provisional Application Ser. No. 60/287,856 filed May 1, 2001, Provisional Application Ser. No. 60/287,763 filed May 1, 2001, Provisional Application Ser. No. 60/288,281 filed May 2, 2001, and Provisional Application Ser. No. 60/288,279 filed May 2, 2001. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to the field of sensing apparatuses and, more particularly, to the field of sensing apparatuses having a sensing element formed in a monolithic semiconductor substrate.  
         BACKGROUND OF THE INVENTION  
         [0003]    Sensing apparatuses are widely used in various types of mechanical and electrical systems for detecting and measuring myriad physical and chemical phenomena. The various uses for such devices include sensing the presence and intensity of electrical and magnetic fields, detecting mechanical forces, measuring the temperature or flow of a liquid or gas, and registering the acceleration of a solid body.  
           [0004]    Over the years various types of sensing devices have been developed to accomplish these disparate tasks. Some of the sensing apparatuses developed rely on a sensing element (e.g. a transducer) having a specific preferred orientation in relation to an electrical or magnetic field or to a mechanical force to be sensed. Typical examples of electrical or magnetic field sensing elements are position and proximity sensors such as a Hall-effect cell, magnetoresistor, capacitive sensing element, and inductive sensing elements. An example of a mechanical force sensing element is a stress gauge that measures mechanical stress or weight of an object. Another example of a mechanical force sensing element is the accelerometer, which measures the acceleration of an object.  
           [0005]    These sensing devices, then, typically have a preferred orientation for the sensing element relative to the electrical or magnetic field or to the physical force being sensed. The device thus must be oriented so that the sensing element has the preferred orientation if the sensor&#39;s sensitivity is to be magnetized. There also may be extraneous electrical or magnetic fields or mechanical forces associated with use of the system with which the sensing device must accommodate, preferably by orienting the sensor relative to these extraneous fields or forces in a specific direction so as to reduce the sensor&#39;s sensitivity to the extraneous fields or forces. Such orientation can reduce sensing errors or noise caused by the presence of other fields or forces within the vicinity of the sensing device or the movement of other objects.  
           [0006]    Sensing apparatuses typically also rely on signal conditioning circuitry to amplify or otherwise condition the sensing signal that typically has too low a magnitude to overcome extraneous noise effects. The signal conditioning circuitry is also employed to condition a sensing signal that contains a large offset or other error signal that can overdrive sensitive monitoring equipment. Indeed, the signal conditioning circuitry can condition a sensing signal not otherwise conducive to transmission over an extended distance to a remotely located electrical device such a sensor monitoring circuit.  
           [0007]    In the manufacture of a sensing apparatus, the sensing element, generally defining a sensor, and the corresponding signal conditioning circuitry defining a signal conditioner are both formed on a common surface of a semiconductor wafer. Conventional techniques for manufacturing a sensing apparatus generally leave the sensor and the signal conditioner on a common, single-plane surface. Conductive traces are then formed directly on the common surface between the sensor and signal conditioner to electrically connect each with the other. Therefore, for a sensing apparatus having a signal conditioner formed in a common plane with the sensor, the combined extent of the surface area required for both the sensor and the signal conditioner will generally dictate the overall size of the sensing apparatus.  
           [0008]    Having the sensor and the signal conditioner formed on a common plane inevitably results in the sensing apparatus having a relatively large surface area relative to the depth of the device. Moreover, because the sensor will of necessity be oriented with respect to the field or force to be sensed, one will be constrained in attempts at orienting the sensing apparatus in a system so as to accommodate the surface area of the sensing apparatus. The electrical and mechanical systems in which sensing apparatuses are employed, however, have become increasingly smaller over the years. Yet the ability to position the sensing apparatus in an electrical or mechanical system of limited size, though, is accordingly severely constrained depending on the preferred orientation of the sensor and the orientation of the signal conditioner relative to the sensor. Thus, there is a need for a sensing apparatus having a smaller surface area than conventional ones having the sensor and signal conditioner positioned in the same plane.  
           [0009]    The amount of area occupied by the sensor is typically much smaller than the area occupied by the signal conditioner. Moreover, in contrast to the sensor, the signal conditioner does not require a specific orientation relative to the electrical or magnetic field or the mechanical force that is to be sensed by the sensing apparatus. One way of achieving a reduced cross section, then, is to physically separate the sensor and signal conditioner, and orient the separated components in separate planes while maintaining the necessary electrical connection between them. Because the electrical and mechanical systems in which the sensing apparatuses will be employed are likely to be subjected to significant stress forces, however, it is necessary to maintain the structural integrity of the sensing apparatus, especially the necessary electrical connection between the sensor and the signal conditioner. Therefore, there also is a need for a sensing apparatus that achieves both a reduction in overall size while maintaining its structural integrity.  
         SUMMARY OF THE INVENTION  
         [0010]    With the foregoing in mind, the present invention advantageously provides a sensing apparatus reduced in size by orienting the sensor and signal conditioner in separate planes while maintaining the overall structural integrity of the device. In addition, the method aspects of the present invention advantageously provide means for forming a compact sensing apparatus having structural integrity.  
           [0011]    More specifically, the present invention provides a compact sensing apparatus having a sensor formed in a surface of a monolithic semiconductor substrate and a signal conditioning circuitry defining a signal conditioner formed in the same semiconductor substrate. The sensor and signal conditioner are oriented relative to each other to advantageously reduce the overall size of the sensing apparatus. The sensor generates a sensing signal in response to a predetermined physical stimulus. The signal conditioner senses the sensing signal generated by the sensor in response to the predetermined physical stimulus. The physical stimulus can be an electric field, a magnetic field, or a mechanical force.  
           [0012]    A significant advantage of the present invention is the orientation of the sensor relative to the signal conditioner. Specifically, the sensor is oriented orthogonally to the signal conditioner and positioned on a surface substantially smaller than the surface on which the signal conditioner is positioned. Orthogonal orientation reduces the lengthwise extent of the sensing apparatus, making the device much more compact than conventional devices having same-plane sensor and signal conditioning circuitry. Specifically, because the depth (or height) and lateral extent of the sensing apparatus will be a function of the surface area of the surface on which the sensor is formed, orienting the sensor orthogonally relative to the surface on which the signal conditioner is formed accordingly reduces the height and lateral extend of the compact sensing apparatus.  
           [0013]    Moreover, because the sensor and signal conditioner are formed on separate planes of a monolithic semiconductor substrate rather than positioned separately, the structural integrity of the sensing apparatus is accordingly enhanced. In addition, the sensor and the signal conditioner are electrically connected via a stable electrical connection that can resist breakage by being formed on the monolithic semiconductor substrate. The electrical connection more specifically can include at least one integrated conductor formed in the monolithic semiconductor substrate by, for example, heavily doping a region of the substrate. The at least one integrated conductors preferably are formed in and extend over an edge portion of the monolithic semiconductor substrate. The edge more specifically is the edge shared by the surface on which the sensor is formed and the separate surface on which the signal conditioner is formed.  
           [0014]    A conductive path between the sensor and the signal conditioner can be provided by including at least one pair of metal conductors also formed on the monolithic semiconductor substrate. One of the at least one pair of metal conductors connects to the at least one integrated conductor and extends along the surface on which the sensor is formed to connect to the sensor. The other of the at least one pair of metal conductors preferably connects to the same at least one integrated conductor and extends along the surface in which the signal conditioner is formed to connect to the signal conditioner. The respective conductors extending from the sensor and the signal conditioner, each on separate planes of the same semiconductor substrate, are electrically connected at the edge-positioned integrated conductor so as to complete a stable, reliable conductive path between the sensor and the signal conditioner.  
           [0015]    The sensor positioned orthogonally on the monolithic substrate can sense electrical or magnetic fields, as well as mechanical forces oriented perpendicularly or horizontally relative to the sensor, depending on the nature of the sensor. More specifically an orthogonal sensor will sense electrical or magnetic fields, or mechanical forces, oriented perpendicularly to the planar surface of the sensor. Alternatively, a transverse sensor can sense electrical or magnetic fields, or mechanical forces that are oriented parallel to the planar surface of the sensor.  
           [0016]    A second conductive path can also be provided, one which links the sensing apparatus to a remote electrical device such as a sensing monitor. The second conductive path, specifically, can include an electrical conductor that electrically connects to the signal conditioner and extends from the signal conditioner to connect to the preselected electrical device, the device being positioned apart from the sensing apparatus. Thus, the conductive path thereby forms a conductive path between the compact sensing apparatus and the remotely positioned preselected electrical device. The preselected electrical device preferably will be a sensing monitor. The compact sensing apparatus also can include a mounting base to which the monolithic substrate is attached to thereby provide a separate or additional support structure underlying the substrate-mounted sensor and substrate-mounted signal conditioner.  
           [0017]    The sensing apparatus, moveover, can further include a housing or other type of encapsulation extending over all or a portion of the sensing apparatus to thereby encapsulate at least a portion of the signal conditioner SO as to provide a protective cover the sensing apparatus. The electrical conductor providing the conductive path between the signal conditioner and a remotely positioned electrical device, then, extends through the encapsulation to thereby electrically connect the sensing apparatus with the sensing monitor or other preselected electrical device.  
           [0018]    In yet an additional embodiment, the sensing apparatus includes an encapsulation extending over the sensor as well as the signal conditioner. Specifically, with respect to a sensor comprising a magnetoresistor or Hall element cell, the encapsulation preferably is a nonmagnetic material that partially encapsulates the sensor and the signal conditioner that are both formed on the monolithic semiconductor substrate. Moreover, the sensor can be a magnetoresistor or Hall element cell. In the case of magnetic sensor, the encapsulation preferably further comprises a magnetic encapsulation that partially encapsulates the sensor and the signal conditioner and is positioned behind the planar surface of the sensor. The magnetic material of the magnetic encapsulation, moreover, is preferably charged in a direction parallel to an imaginary straight line extending between the sensor and the magnetic encapsulation, the line being generally perpendicular to both the planar surface of the sensor and the edge of the magnetic encapsulation that is closest to or abuttingly in contact with the monolithic semiconductor substrate. In each of the respective embodiments of the present invention, the sensors can be any of a variety of sensing element types that generate a sensing signal in response to one of a host of physical stimuli. The sensor, for example, can be a magnetoresistor or a Hall-effect cell for detecting magnetic fields, as already noted. The sensor alternatively can be capacitive transducer for detecting electrical fields. Types of sensors also include ones for detecting mechanical forces such as pressure sensors, flow sensors, and accelerometers. These and a host of other types of sensors can be accommodated with the present invention as will be readily apparent to those of skilled in the relevant art.  
           [0019]    The present invention, moreover, encompasses various method aspects as well. The present invention provides a method for forming a compact sensing apparatus that includes positioning a signal conditioner on a monolithic semiconductor substrate. The monolithic semiconductor substrate, for example, can be cut from a wafer of semiconductor material on which a signal conditioner has been formed. Preferably, a plurality of signal conditioners will be formed on one wafer surface in order to efficiently form multiple sensing apparatuses. After the plurality of signal conditioners is formed on the wafer surface, the wafer surface is cut into multiple monolithic semiconductor substrates, each of which has a signal conditioner formed thereon. If the signal conditioner has been formed on the surface of the wafer and the wafer cut into an individual monolithic semiconductor substrate, the substrate (or each of a plurality of substrates) is then rotated appropriately so that a sensor can be formed on a distinct plane of the monolithic semiconductor substrate. The sensor and the signal conditioner will be electrically connected and oriented orthogonally relative to each other.  
           [0020]    The method aspects of the invention further include forming at least one integrated conductor on the monolithic semiconductor substrate, preferably by doping the monolithic semiconductor substrate with a suitable material for making the semiconductor conductive so as to thereby form the integrated conductor having the desired conductive properties for completing a conductive path between the sensor and the signal conditioner. Using the at least one integrated conductor as an electrical juncture, the conductive path between the sensor and the signal conditioner can be completed by electrically connecting the sensor to at least one integrated conductors and electrically connecting the signal conditioner to the same integrated conductor to thereby form the conductive path. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]    Some of the features, advantages, and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings in which:  
         [0022]    [0022]FIG. 1 is a perspective view of a sensing apparatus according to the present invention;  
         [0023]    [0023]FIG. 2 is a perspective view of a mounted sensing apparatus according to the present invention;  
         [0024]    [0024]FIG. 3 is a side elevational view of a sensing apparatus according to the present invention;  
         [0025]    [0025]FIG. 4 is a side elevational view of a sensing apparatus according to the present invention;  
         [0026]    [0026]FIG. 5 is perspective view a sensing apparatus according to the present invention;  
         [0027]    [0027]FIG. 6 is a perspective view of a sensing apparatus according to the present invention;  
         [0028]    [0028]FIG. 6A is a cross sectional view of a sensing apparatus according to the present invention; and  
         [0029]    [0029]FIG. 7 is a perspective view of a sensing apparatus according to the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0030]    The present invention will now be described more fully hereinafter with reference to the accompanying drawings which illustrate preferred embodiments of the invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout, the prime notation, if used, indicates similar elements in alternative embodiments.  
         [0031]    [0031]FIG. 1 illustrates a compact sensing apparatus  20  according to a first embodiment of the present invention. The compact sensing apparatus  20  includes a monolithic substrate  22  having a sensor surface  24  and a signal conditioner surface  26 , a sensor  34  formed on the sensor surface  24  for generating a sensing signal in response to a predetermined physical stimulus. The compact sensing apparatus  20  further includes signal conditioning circuitry defining a signal conditioner  36 , the signal conditioner  36  being formed in the signal conditioner surface  26  of the monolithic semiconductor substrate  22 . The signal conditioner  36 , moreover, is electrically connected to the sensor  34  for conditioning the sensing signal generated by the sensor  34  in response to the predetermined physical stimulus. A sensing apparatus formed on a monolithic substrate is illustrated in U.S. Pat. No. 5,670,886 to Applicants titled Method and Apparatus for Sensing Proximity or Position of an Object Using Near-Field Effects, the disclosures of which are incorporated herein in their entirety. As will be readily understood by those skilled in the art, the physical stimulus can be an electric field, a magnetic field, or a mechanical force.  
         [0032]    A significant advantage of the present invention is the orientation of the sensor  34  relative to the signal conditioner  36 . Preferably, the sensor  34  is oriented orthogonally to the signal conditioner  36 . Orthogonal orientation reduces the lengthwise extent L of the sensing apparatus  20 , making the device much more compact than conventional devices having same-plane sensor and signal conditioning circuitry. (See FIG. 2.) A sensor formed on a substrate and oriented orthogonally to a signal conditioner also formed on the substrate is illustrated in applicants&#39; co-pending application titled Compact Sensing Having an Orthogonal Sensor Formed in a Monolithic Substrate and in U.S. Pat. No. 5,670,886 to applicants titled Method and Apparatus for Sensing Proximity or Position of an Object Using Near-Field Effects, the disclosures of which are incorporated herein in their entirety.  
         [0033]    Moreover, according to the present invention, advantage can be taken of the fact that the circuitry required for the signal conditioner  36  is typically more extensive than that associated with the sensor  34 . Specifically, because the height H and lateral extent W of the sensing apparatus  20  will be a function of the surface area of the sensor surface  24  when the sensor  34  is orthogonal to the signal conditioner  36 , the sensor surface  24  preferably is smaller than the signal conditioner surface  26  to thereby reduce the height and lateral extend of the compact sensing apparatus  20 . (See FIG. 2)  
         [0034]    As further illustrated in FIG. 1, the signal conditioner  36  preferably is electrically connected to the sensor  34  via a conductive path comprising at least one integrated conductor  42  formed in the monolithic semiconductor substrate  22  and extending over an edge portion  44  of the monolithic semiconductor substrate  22 , the edge specifically being the edge shared by the sensor surface  24  and the signal conditioner surface  36 . The conductive path, moreover, preferably also includes at least one pair of metal conductors  46 , 48  formed on the monolithic semiconductor substrate  22 . More specifically, one of the at least one pair of metal conductors  46  connects to the at least one integrated conductor  42  and extends along the sensor surface  24  to connect to the sensor  34  formed therein. The other of the at least one pair of metal conductors  48 , then, preferably connects to the at least one integrated conductor  42  and extends along the signal conditioner surface  26  to connect to the signal conditioner  36  formed therein to thereby complete the conductive path between the sensor  34  and the signal conditioner  36 .  
         [0035]    Preferably, each of the at least one integrated conductors  42  is formed by heavily doping the monolithic semiconductor substrate  22  in at least one region of the monolithic semiconductor substrate  22  wherein that region extends over an edge portion of the monolithic semiconductor substrate  22  and the edge is that edge shared by the sensor surface and the signal conditioner surface. A conductor, such as a metal conductor, can then connect to the sensor  34  and extend from the sensor  34  along the sensor surface  24  to one of the at least one edge-positioned integrated conductors  42  to thereby form an electrical connection between the sensor and the integrated conductor. Similarly, another conductor—again, for example, a metal conductor—can connect to the signal conditioner  36  and extend therefrom along the signal conditioner surface  26  to the same at least one integrated conductors  42  to thereby electrically connect the signal conditioner  36  to the integrated conductor  42 . Thus, the sensor  24  and the signal conditioner jointly connect electrically to a same at least one integrated conductor  42  thereby completing the conductive path between the sensor  34  and the signal conditioner  36 .  
         [0036]    As illustrated in FIGS.  3 - 4 , a sensor positioned orthogonally on the monolithic substrate  22  can sense electrical or magnetic fields, as well as mechanical forces, oriented perpendicularly or horizontally relative to the sensor, depending on the nature of the sensor  34 . More specifically an orthogonal sensor  34  will sense electrical E or magnetic fields B, or mechanical forces F, oriented perpendicularly to the planar surface of the sensor  34 . (See FIG. 3) Alternatively, a transverse sensor  34 ′ can sense electrical E or magnetic fields B, or mechanical forces F that are oriented parallel to the planar surface of the sensor  34 ′. (See FIG. 4) In each case the field or force is generated by an entity  50  spaced apart from the sensing apparatus mounted sensor  34 , 34 ′.  
         [0037]    [0037]FIG. 5 illustrates a second embodiment of the present invention wherein the conductive path between the sensor  134  and the signal conditioner  136  defines a first conductive path, and the sensing apparatus  120  further includes a second conductive path. The second conductive path, specifically, includes an electrical conductor  160  that is electrically connected to the signal conditioner  136  and extends therefrom to connect to a preselected electrical device  170  positioned apart from the sensing apparatus  120 . Thus, the conductive path thereby forms a conductive path between the compact sensing apparatus  120  and the remotely positioned preselected electrical device  170 . The preselected electrical device  170  preferably will be a sensing monitor. The compact sensing apparatus  120 , as also illustrated in FIG. 5, can further include a mounting base  180  to which the monolithic substrate  122  is attached to thereby provide a separate or additional support structure underlying the substrate-mounted sensor  124  and substrate mounted signal conditioner  126 .  
         [0038]    As further illustrated in FIGS. 6, 6A the sensing apparatus  120  can further include a housing or other type of encapsulation extending over all or a portion of the sensing apparatus  120  to thereby encapsulate at least a portion of the signal conditioner  136  so as to provide a protective cover therefor. The electrical conductor  160  providing a conductive path between the signal conditioner  136  and a remotely positioned electrical device  170 , then, extends through the encapsulation to thereby electrically connect the sensing apparatus  120  and the preselected electrical device  170 .  
         [0039]    [0039]FIG. 7 illustrates a third embodiment of the present invention, the sensing apparatus  220  having an encapsulation extending over the sensor  234  formed on the sensor surface  224  as well as the signal conditioner formed on the signal conditioning surface  226 . With respect to a sensor  234  comprising a magnetoresistor or Hall element cell, the encapsulation preferably is a nonmagnetic material that partially encapsulates the monolithic semiconductor substrate  222 , the sensor  234  formed in the substrate, and the signal conditioner  236  formed in the substrate. Moreover, as illustrated, a sensing apparatus  220  having a sensor  234  comprising a magnetoresistor or Hall element cell further comprises a magnetic encapsulation  228  that partially encapsulates the monolithic semiconductor substrate  222 , the sensor  234  formed in the substrate  222 , and the signal conditioner  236  formed in the substrate  222 . More specifically, the magnetic encapsulation  228  is behind the planar surface of the sensor  234  formed on the sensor surface  224  and the magnetic material of the magnetic encapsulation  228  is preferably charged in a direction parallel to an imaginary straight line extending between the sensor  234  and the magnetic encapsulation  228 , the line being generally perpendicular to both the planar surface of the sensor  234  and the edge of the magnetic encapsulation  228  that is closed or abuttingly in contact with the monolithic semiconductor substrate  222 .  
         [0040]    Further, the second conductive path, as illustrated in FIG. 7, preferably is provided by an output wire  262  and ground wire  264 . An electrical connection with the signal conditioner  236  preferably is be made by contacting the output wire  262  and the ground wire  264  to wirebond pads  227 ,  229  formed on the monolithic substrate  222  and electrically connected to the signal conditioner  236  as also illustrated in FIG. 7. The connection between the wirebond pads  227 ,  229  and the output wire  262  and the ground wire  264 , respectively, is preferably held in place by use of a conductive epoxy that causes the output wire  262  and the ground wire  264  to adhere to the wirebond pads  227 ,  229 .  
         [0041]    As with respect to the first embodiment, the sensors  134 ,  234  comprising the second and third embodiments of the invention likewise can be any of various types of sensing elements for generating a sensing signal in response to a host of physical stimuli. The sensor, for example, can be a magnetoresistor or a Hall effect cell for detecting magnetic fields B. The sensor alternatively can be capacitive transducer for detecting electrical fields E. Types of sensors also include ones for detecting mechanical forces F such as pressure sensors, flow sensors, and accelerometers. These and a host of other types of sensors can be accommodated with the present invention as will be readily apparent to those of ordinary skill in the relevant art.  
         [0042]    FIGS.  1 - 7 , moreover, illustrate method aspects of the present invention. The method for forming a compact sensing apparatus includes positioning a signal conditioner  36 , 136 ,  236  on a monolithic semiconductor substrate. The monolithic semiconductor, for example, can be cut from a wafer of semiconductor material on which a signal conditioner  36 , 136 ,  236  has been formed. Preferably, a plurality of signal conditioners will be formed on one wafer surface in order to efficiently form multiple sensing apparatuses  20 ,  120 ,  220 . After the plurality of signal conditioners is formed on the wafer surface, the wafer surface is cut into multiple monolithic semiconductor substrates, each of which has a signal conditioner formed thereon. If the signal conditioner  36 , 136 ,  236  has been formed on the surface of the wafer and the wafer cut into an individual monolithic semiconductor substrate  22 ,  122 ,  222 , the substrate (or each of a plurality of substrates) is then rotated. A sensor  34 , 134 ,  234  is then formed, the sensor  34 , 134 ,  234  and the signal conditioner  36 ,  136 ,  236 , being electrically connected and oriented orthogonally relative to each other.  
         [0043]    The method further includes forming at least one integrated conductor  42 , 142 ,  242  on the monolithic semiconductor substrate. Preferably, the at least one integrated conductor is formed by doping the monolithic semiconductor substrate with an appropriate trivalent, pentavalent, or other doping material for making the semiconductor conductive so as to thereby form the integrated conductor having the desired conductive properties for completing a conductive path between the sensor  34 , 134 , 234  and the signal conditioner  36 , 136 , 236 . Using the at least one integrated conductor  42 , 142 ,  242  as an electrical juncture, the conductive path between the sensor  34 , 134 ,  234  and the signal conditioner  36 , 136 ,  236  is completed by electrically connecting the sensor  34 , 134 ,  234  to one of the at least one integrated conductors  42 , 142 ,  242  and electrically connecting the signal conditioner  36 ,  136 ,  236  to the same integrated conductor  42 , 142 ,  242  to thereby form the conductive path.  
         [0044]    In the drawings and specification, there have been disclosed a typical preferred embodiment of the invention, and although specific terms are employed, the terms are used in a descriptive sense only and not for purposes of limitation. The invention has been described in considerable detail with specific reference to these illustrated embodiments. It will be apparent, however, that various modifications and changes can be made within the spirit and scope of the invention as described in the foregoing specification and as defined in the appended claims.