Patent Document

[0001]    The present application claims priority from: U.S. Provisional Application No. 61/860,106 filed Jul. 30, 2013, the entire disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    The present invention relates to a thermometer device and a method of manufacturing a thermometer device. 
         [0003]    Conventional thermometer devices are designed to sense the temperature of the desired object and display the temperature to the user. In some cases, the thermometer is preheated close to a target temperature (for example, the temperature of the human body) such that the time required to obtain the final temperature is minimized. 
         [0004]    Such thermometers, while being fast and convenient to use, are generally difficult to manufacture, requiring intricate assembly steps that are time consuming and costly. 
         [0005]      FIG. 1A  illustrates a conventional thermometer device  100 . 
         [0006]    As shown in the figure, device  100  includes probe housing  102 , probe  104 , probe tip  110 , flexible cable  106  and connector  108 . 
         [0007]    Probe tip  110  serves to sense the surrounding temperature. Probe tip  110  will be described in greater detail with reference to  FIG. 1B . Probe  104  connects to probe tip  110  and probe housing  102 . Probe  104  is typically manufactured from metal or any other material that is a good heat conductor. Probe housing  102  connects to flexible cable  106 , and flexible cable  106  connects to connector  108 . 
         [0008]    In operation, when a practitioner desires to take the temperature of a patient, connector  108  is plugged into a display module (not shown) that is capable of reading and displaying the temperature at probe tip  110 . When the display module is activated, probe tip  110  is preheated to a temperature close to the target temperature of the patient. For example, the target temperature may be 96.5° Fahrenheit. Once preheated, probe tip  110  is placed at the location from which the temperature reading is desired. The temperature at the desired location is transmitted from probe tip  110 , to probe  104 , to probe housing  102 , to flexible cable  106 , to connector  108  and finally to the display module, where the temperature is displayed to the practitioner. 
         [0009]      FIG. 1B  illustrates probe tip  110  of device  100 . 
         [0010]    Probe tip  110  includes a temperature sensor  112 , sensor wires  114 , a heating element  116  and heating element wires  118 . 
         [0011]    Temperature sensor  112  may be a thermistor, thermocouple or any other device that can accurately sense temperature in an area. Temperature sensor  112  is attached to the inside surface of probe tip  110 , which is typically a labor-intensive process that requires very skilled workers and is not totally repeatable from one device to the next. The process is manual and requires an operator to use very small tools, so placing temperature sensor  112  in the same location, with the same surface area contact to probe tip  110  every time is very difficult and time consuming. Sensor wires  114  connect temperature sensor  112  to a control module (not shown) in probe housing  102 . 
         [0012]    Heating element  116  may be a resistor, etched foil, nichrome, or any other element that can rapidly heat a surface. Like temperature sensor  112 , heating element  116  is also attached to the inside surface of probe tip  110 , which again is typically a labor-intensive process that requires very skilled workers and is not totally repeatable from one device to the next. Heating element wires  118  connect heating element  116  to the control module (not shown) in probe housing  102 . 
         [0013]    In operation, when the connector  108  is plugged into the display module and the display module is powered on the control module in probe housing  102  provides power to heating element  116 . As probe tip  110  begins to heat up, temperature sensor  112  relays temperature signals via sensor wires  114  to the control module. A feedback loop is thus created between the control module, heating element  116  and temperature sensor  112  such that probe tip  110  can be preheated to within a few degrees of an expected (normal) temperature and maintain that temperature until it is ready to use on a patient. 
         [0014]    When it is ready for patient use, the practitioner will place probe tip  110  in the target area, and temperature sensor  112  will sense the surrounding temperature, which will typically be higher than the preheated temperature. The display module will continue to read data regarding the temperature of the target area until the temperature reading reaches a steady state, at which point probe tip  110  has reached the temperature of the target area. The display module will then display the temperature of the target area for the practitioner to read. 
         [0015]    What is needed is a temperature sensing device that is simple to manufacture, has a manufacturing process that may be automated and that evenly and quickly preheats. 
       BRIEF SUMMARY 
       [0016]    The present invention provides temperature sensing device that is simple to manufacture, has a manufacturing process that may be automated and that evenly and quickly preheats. 
         [0017]    In accordance with aspects of the present invention, method of manufacturing a thermometer probe includes: obtaining a hollow housing having an open end and a curved inner surface; obtaining a flexible detecting component having an adhesive layer; obtaining an insertion component; detachably attaching the flexible detecting component to the insertion component; inserting the insertion component, having the flexible detecting component attached thereto, through the open end of the hollow housing and into the hollow housing such that the adhesive layer is disposed between the insertion component and the inner surface; and adhering, via the adhesive layer, the flexible detecting component to the curved inner surface. 
         [0018]    Additional advantages and novel features of the invention are set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
     
    
     
       BRIEF SUMMARY OF THE DRAWINGS 
         [0019]    The accompanying drawings, which are incorporated in and form a part of the specification, illustrate example embodiments and, together with the description, serve to explain the principles of the invention. In the drawings: 
           [0020]      FIGS. 1A-B  illustrate a conventional thermometer device; 
           [0021]      FIGS. 2A-F  illustrate planar views of an example manufacturing process of a flexible circuit in accordance with aspects of the present invention; 
           [0022]      FIGS. 3A-C  illustrate alternative embodiments of the manufacturing process described with reference to  FIGS. 2A-E ; 
           [0023]      FIGS. 4A-B  illustrate an insertion component used in manufacturing a temperature sensing device in accordance with aspects of the present invention; 
           [0024]      FIGS. 5A-F  illustrate an assembly process employed to assemble a temperature sensing device in accordance with aspects of the present invention; 
           [0025]      FIG. 5G  illustrates an alternate view of  FIG. 5F ; 
           [0026]      FIG. 5H  illustrates an alternate embodiment of the assembly process referenced in  FIGS. 5A-E ; 
           [0027]      FIG. 5I  illustrates a final assembly configuration of a temperature sensing device in accordance with aspects of the present invention; and 
           [0028]      FIG. 6  illustrates an alternate assembly configuration for a temperature sensing device in accordance with aspects of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    The present invention is drawn to a flexible heating element for use in a temperature sensing device and a method of assembling the temperature sensing device having the flexible heating element. A flexible circuit includes both the beating element and the temperature sensing element for use within the hollow probe tip the temperature sensing device. The flexible circuit can be bent without any effects detrimental to the function of either the heating element or the temperature sensing element. Further, because it is flexible, the heating element may conformingly affix to the curved inner surface of the probe tip. 
         [0030]    During assembly, the flexible circuit can be bent for easy insertion into the probe tip. In some embodiments an assembly tool, which includes an expandable section, may be used. In a specific embodiment, the expandable section may be an inflatable balloon. The flexible circuit and inflatable balloon are then inserted into a temperature probe for deployment of the flexible circuit. The inflatable balloon is inflated until the flexible circuit contacts the inner surface of the probe. An adhesive on the flexible circuit serves to adhere the flexible circuit to the inner surface of the probe. The balloon is then deflated and removed. 
         [0031]    The assembly method described above provides for much easier manufacturing than conventional methods. Using a flexible circuit allows for much more consistency in the preheating and temperature sensing elements, since they can be assembled without restrictions from the temperature probe. In addition, utilizing the inflatable balloon allows for consistent attachment of the flexible circuit to the probe, such that a more reliable temperature sensing device can be manufactured. 
         [0032]    Example aspects of the present invention will now be further described with reference to  FIGS. 2A-6 . 
         [0033]      FIGS. 2A-F  illustrate planar views of an example manufacturing process of a flexible circuit in accordance with aspects of the present invention. 
         [0034]      FIG. 2A  illustrates a first step in an example manufacturing process of a flexible circuit in accordance with aspects of the present invention. 
         [0035]    As shown in the figure, a flexible circuit base  200  is provided. Flexible circuit base  200  includes supply portion  202  and head portion  204 . Flexible circuit base  200  may be constructed from polyimide, PEEK, polyester, polyethylene napthalate, polyetherimide, FEP or any other material that is able to provide a flexible substrate. Flexible circuit base  200  may include a removable film that when removed, exposes an adhesive layer. 
         [0036]      FIG. 2B  illustrates a second step in an example manufacturing process of a flexible circuit in accordance with aspects of the present invention. 
         [0037]    As shown in the figure, the second step includes adding heating element  206  and sensor attachments  208 - 214  to flexible circuit base  200 . Probe housing  102  provides power to heating element  206  by way of power line  211 , which extends from supply portion  202 . Probe housing  102  additionally communicates with sensor attachments  208 - 214  via wires  213  that extend from head portion  204 . 
         [0038]    Heating element  206  may be a conductive material that is able to conduct current in order to generate resistive heat. In some embodiments, heating element  206  may be constructed from resistance wire that is disposed on flexible circuit base  200 . In some embodiments, heating element  206  may be deposited by any known deposition method, a non-limiting example of which includes chemical vapor deposition. In this example embodiment, heating element  206  is a serpentine winding of a portion of power line  211 . In other non-limiting examples, heating element may be any arrangement, coiling or winding of power line  211 . Heating element  206  is located on head portion  204  and is operable to preheat a temperature sensing device when the device is fully assembled. The distribution of power line  211  enables a relatively quick and distributed heating of the area of head portion  204 . 
         [0039]    Sensor attachments  208 - 214  may be conductive pads that are disposed to provide a base to which a sensor will be subsequently attached. In some embodiments, sensor attachments  208 - 214  may be constructed from a conductive material that is disposed on flexible circuit base  200 . In some embodiments, sensor attachments  208 - 214  may be deposited by any known deposition method, a non-limiting example of which includes chemical vapor deposition. In some embodiments, sensor attachments  208 - 214  may be located on head portion  204 , while in other embodiments, sensor attachments  208 - 214  may be located on supply portion  202 . 
         [0040]    The heating element  206  is shown in one configuration in  FIG. 2B , however it can be appreciated that heating element  206  may be disposed on flexible circuit base  200  in any other pattern that would provide heat in accordance with aspects of the present invention. In addition, sensor attachments  208 - 214  are also disposed on flexible circuit base  200 . In this example, sensor attachments  208 - 214  are arranged in a particular configuration. However, sensor attachments  208 - 214  may be arranged in any other configuration that would enable connection of a temperature detecting device in accordance with aspects of the present invention. 
         [0041]      FIG. 2C  illustrates a third step in an example manufacturing process of a flexible circuit in accordance with aspects of the present invention. 
         [0042]    As shown in the figure, the third step includes adding a temperature sensor  216 . Temperature sensor  216  is attached to sensor attachments  208 - 214  (not shown) by any known method or system, a non-limiting example of which includes an adhesive. 
         [0043]      FIG. 2D  illustrates a fourth step in the example manufacturing process of a flexible circuit in accordance with aspects of the present invention. 
         [0044]    As shown in the figure, the fourth step includes adding adhesive layer  220  on top of heating element  206  and temperature sensor  216  to create an attachable flexible circuit  218 . Adhesive layer  220  provides adhesion while still allowing the assembly to remain flexible. 
         [0045]      FIG. 2E  illustrates attachable flexible circuit  218  being attached to the inside surface of a probe tip  222 . 
         [0046]    As shown in the figure, flexible circuit  218  is conformingly adhered to the curved inner surface of probe tip  222  using a method that will be described in more detail with reference to  FIGS. 5A-F . In general, adhesive layer  220  is conformingly adhered to the inner surface of probe tip  222  such that flexible circuit  218  is in conforming contact with the curved inner surface of probe tip  222 . 
         [0047]      FIG. 2F  illustrates a cross sectional view of flexible circuit  218 . 
         [0048]    As shown in the figure, heating element  206  and temperature sensor  216  are disposed on head portion  204  of flexible circuit  218 . Adhesive layer  220  is disposed on heating element  206  and temperature sensor  216 . Adhesive layer  220  is a relatively weak adhesive that enables flexible circuit  218  to be detachably fixed to an insertion component to aid in assembly such that neither heating element  206  nor temperature sensor  216  are damaged during the insertion or detachment process. The insertion component and its interaction with flexible circuit  218  will be further described with reference to  FIGS. 4A-B  and  5 A-E. 
         [0049]    Additional example embodiments of a flexible circuit in accordance with aspects of the present invention will now be described with reference to  FIGS. 3A-C . 
         [0050]      FIG. 3A  illustrates another example embodiment of a flexible circuit  300  in accordance with aspects of the present invention. 
         [0051]    As shown in the figure, flexible circuit  300  is similar to flexible circuit  218 . However, flexible circuit  300  includes a temperature sensor  302  that is located in a different position than temperature sensor  212  of flexible circuit  218 . Providing temperature sensor  302  on supply portion  202  instead of head portion  204  may allow heating element  206  to reach the desired temperature earlier since more surface area of head portion  204  would be covered by heating element  206 . 
         [0052]      FIG. 3B  illustrates another example embodiment of a flexible circuit  304  in accordance with aspects of the present invention. 
         [0053]    As shown in the figure, temperature sensor  306  is located in a different position than shown in  FIG. 2C , as described with reference to  FIG. 3A . It is also located on a separate flexible circuit base  308  that is disposed on top of heating element  206 , and heating element  206  is disposed on flexible circuit base  200 . Thus, the circuit can be manufactured by disposing temperature sensor  306  on flexible circuit base  308 , and separately disposing heating element  206  on flexible circuit base  200 . Then, flexible circuit base  308  may be disposed on top of flexible circuit base  200 , or vice versa, to create flexible circuit  304 . Manufacturing the circuit in this manner may simplify the assembly by only requiring one component to be adhered to each of flexible circuit bases  200  and  308 . 
         [0054]      FIG. 3C  illustrates another example embodiment of a flexible circuit  310  in accordance with aspects of the present invention. 
         [0055]    As shown in the figure, flexible circuit  310  is different from flexible circuit  220 , such that it can better conform to the shape of probe tip  222 . In particular, head portion  312  includes tapered end  314  to match tapered end  316  of probe tip  222 . 
         [0056]    Previous methods of disposing a heating element and temperature sensor into the probe tip required operators to painstakingly adhere the elements to the inner surface of the probe tip. This required the use of small tools to enable the operator to position the parts properly within the probe tip. The conventional method was manually limited and precise replication from one assembled device to another was non-existent. It can be compared to making a ship in a bottle, each one is painstaking slow in assembly and each resulting assembly is slightly different from the next. 
         [0057]    In accordance with aspects of the present invention, the heating element and temperature sensor, being attached to the flexible base, are inserted into the probe tip using an inflatable member. This method may be automated, thus increasing assembly speed and increasing precision and duplication. In one example method, the head portion of the flexible circuit may be wrapped around the inflatable member, which is inserted into the probe tip and then inflated. Inflating the inflatable member serves to push the head portion of the flexible base against the inner wall of the probe tip, such that the head portion conformingly adheres to the curved inner surface of the probe tip. This will now be further described with reference to  FIGS. 4A-B . 
         [0058]      FIG. 4A  illustrates an insertion component in a first configuration, used in manufacturing a temperature sensing device in accordance with aspects of the present invention. 
         [0059]    As shown in the figure, insertion component  400  includes outer tube  402 , inner tube  404 , seal flange  406  and inflatable portion  408 . 
         [0060]    Outer tube  402  and inner tube  404  may be constructed from metal, plastic, or any other material that can resist expansion under pressure or vacuum that is sufficient to inflate inflatable portion  408 . Outer tube  402  is operable to connect to seal flange  406  and provide a conduit through which vacuum can be pulled. Inner tube  404  is operable to connect to inflatable portion  408  and provide a conduit through which fluid may be used to inflate inflatable portion  408 . 
         [0061]    Seal flange  406  is connected to outer tube  402  and is operable to create a seal when it is pressed against a mating surface. Seal flange  406  may be made of rubber, silicone, or any other material suitable to create a seal. 
         [0062]    Inflatable portion  408  is connected to inner tube  404  and is operable to inflate when positive pressure is provided inside inflatable portion  408 , when negative pressure is provided outside inflatable portion  408 , or a combination of both. Inflatable portion  408  may be made of a compliant or non-compliant material. If a compliant material is used, the walls of inflatable portion  408  will stretch as it is inflated, thus it may be beneficial to use a compliant material if probe tips of different diameters are being produced. Thus, a single insertion component could be used to manufacture multiple sizes of probe tips. A non-limiting example of a compliant material is latex. If a non-compliant material, such as nylon, is used, the walls of inflatable portion  408  will not stretch as it is inflated. Instead, inflatable portion  408  would be created such that, when fully inflated, the outer diameter of inflatable portion  408  is substantially equivalent to the inner diameter of the probe tip. In a manufacturing process, this may be beneficial because the inflatable portion, when inflated with a specific volume of inflation material, will reach the same inflated size every time. This leads to a repeatable, reliable assembly process when one size probe tip is being manufactured. A non-limiting example of a non-compliant material is nylon. 
         [0063]    The operation of insertion component  400  is further described with reference to  FIG. 4B . 
         [0064]      FIG. 4B  illustrates insertion component  400  in a second configuration, used in manufacturing a temperature sensing device in accordance with aspects of the present invention. 
         [0065]    As shown in the figure, inflatable portion  408  is in an expanded configuration. The expansion can occur based on a pressure differential between the volume within inner tube  404  and the volume between inner tube  404  and outer tube  402 . 
         [0066]    In one embodiment, inflatable portion  408  expands as pressure is introduced through inner tube  404 . For example, the pressure within inner tube  404  increases when fluid is introduced into inner tube  404 , as shown by the arrow marked “A”. As pressure within inner tube  404  increases, the diameter of inner tube  404  does not increase. In contrast, the same pressure in inner tube  404  will be present in the interior volume of inflatable portion  408 , as inner tube  404  and inflatable portion  408  are in fluid communication with each other. As pressure increases in the interior volume of inflatable portion  408 , inflatable portion  408  will expand. Any fluid may be used non-limiting examples of which include air and water. 
         [0067]    In another embodiment, inflatable portion  408  expands when pressure decreases in the volume between inner tube  404  and outer tube  402 . For example, the pressure in the volume between inner tube  404  and outer tube  402  may decrease by suctioning air through outer tube  402  (as shown by the arrow marked “B”), while seal flange  406  is properly sealed against another surface. Expanding inflatable portion  408  in this manner may require inner tube  404 , outer tube  402  and the surface against which seal flange  406  is sealed to be rigid in order to maintain structural rigidity under suction. 
         [0068]    In another embodiment, a combination of pressurized fluid and suction may be used together in order to inflate the inflatable member to the desired size. For example, the pressure in the volume within inner tube  404  may be increased by introducing fluid into inner tube  404 , as shown by the arrow marked “A,” and the pressure in the volume between inner tube  404  and outer tube  402  may be decreased by suctioning air through outer tube  402  (as shown by the arrow marked “B”), while seal flange  406  is properly sealed against another surface. 
         [0069]    Insertion component  400  is used to conformingly affix flexible circuit  218  to the curved inner surface of probe tip  222  as will be described in more detail with reference to  FIGS. 5A-F . 
         [0070]      FIG. 5A  illustrates a first step of assembling a temperature sensing device in accordance with aspects of the present invention. (Shows the heater element.) 
         [0071]    As shown in the figure, system  500  includes flexible circuit  591  and insertion component  499 . Flexible circuit  591  is disposed against inflatable portion  498  in preparation for deployment of flexible circuit  591 . In some embodiments, the surface of flexible circuit  501  may be coated with an adhesive in order to maintain contact between flexible circuit  501  and inflatable portion  408 . The adhesive layer will be described in greater detail with reference to  FIG. 5B . The adhesive used for this purpose should be relatively weak as compared to adhesive layer  214 , which is coated on the surface of flexible circuit  220  that is not in contact with inflatable portion  408 . 
         [0072]      FIG. 5B  illustrates a cross sectional view of flexible circuit  501 . 
         [0073]    As shown in the figure, flexible circuit  501  includes all of the elements discussed with reference to flexible circuit  218 , but also includes adhesive  502  and peel-off layer  504 . 
         [0074]    Adhesive  502  is a stronger adhesive than adhesive  224 , and enables flexible circuit  501  to stick to another surface. Once adhesive layer  502  deposited on head portion  204 , in some embodiments, peel-off layer  504  may be added. In this manner, flexible circuit  501  can be mass manufactured with peel-off adhesives. When flexible circuit  501  is to be added or inserted into a probe tip, the peel-off layer can be removed so adhesive layer  502  can be conformingly attached to the curved inner surface of the probe housing. Employing this method will allow for a plurality of flexible circuit boards to be prefabricated and stored, such that the peel-off layer can be removed at the time of assembly. The attachment process will be further described with reference to  FIGS. 5C-E . 
         [0075]    In other embodiments, once adhesive  504  is applied to head portion  204 , flexible circuit  501  can be inserted and attached to the inside of the probe housing. In this embodiment the entire device is made at one time (there is no need to store a plurality of ready to use flexible circuits as discussed above). With reference to  FIGS. 5C-E , it is assumed that the peel-off layer has ahead been removed. 
         [0076]      FIG. 5C  illustrates the second step of assembling a temperature sensing device in accordance with aspects of the present invention. 
         [0077]    As shown in the figure, system  506  includes flexible circuit  501  and insertion component  400 . In this step, flexible circuit  501  is wrapped around inflatable portion  408 . Weak adhesive layer  224  will serve to adhere flexible circuit  501  to inflatable portion  408 . 
         [0078]      FIG. 5D  illustrates the third step of assembling a temperature sensing device in accordance with aspects of the present invention. 
         [0079]    As shown in the figure, system  508  includes flexible circuit  501 , insertion component  400  and probe tip  222 . In this step, the assembly of the wrapped flexible circuit  501  and insertion component  400  is inserted into probe tip  222 . Insertion is continued until seal flange  406  contacts and seals against probe tip  222 . 
         [0080]      FIG. 5E  illustrates the fourth step of assembling a temperature sensing device in accordance with aspects of the present invention. 
         [0081]    As shown in the figure, system  510  includes insertion component  400  in an expanded state, flexible circuit  501  and probe tip  222 . In an example embodiment, an operator will inflate inflatable portion  408  by either introducing fluid through inner tube  404  (shown by arrow “A”), suctioning fluid through outer tube  402  (shown by arrow “B”), or using some combination thereof. Inflatable portion  408  will continue to be expanded until flexible circuit  501  contacts the inner surface of probe tip  222 , thus putting adhesive  502  in contact with the inner surface of probe up  222  as well. Adhesive  502  adheres to the inner surface of probe tip  222 . 
         [0082]      FIG. 5F  illustrates the fifth step of assembling a temperature sensing device in accordance with aspects of the present invention. 
         [0083]    As shown in the figure, system  512  includes flexible circuit  501  and probe tip  222 . In this step, inflatable member  408  has been deflated and removed from probe tip  222 , leaving flexible circuit  501  adhered to the inner surface of probe tip  222 . The process of deflating inflatable member  408  includes detaching inflatable member  408  from flexible circuit  220 . As discussed with reference to  FIG. 5A , adhesive layer  224  between inflatable member  408  and flexible circuit  501  provides a weak bond as compared to adhesive layer  502  between flexible circuit  501  and the inner surface of probe tip  222 . Thus, when inflatable member  408  is deflated, the weak bond between inflatable member  408  and flexible circuit  501  is broken, allowing insertion component  400  to be removed, leaving flexible circuit  501  attached to the inner surface of probe tip  222 . 
         [0084]      FIG. 5G  illustrates an alternate view of the system in  FIG. 5F . 
         [0085]    As shown in the figure, a 3-dimensional view of system  512  is shown. It can be appreciated that, while inflatable member  408  is expanding as shown in  FIG. 5E , flexible circuit  501  is deforming so as to conform to the curved inner surface of probe tip  222 . As a non-limiting example, the two free ends of flexible circuit  501  may be in contact with one another when flexible circuit  501  is wrapped around inflatable member  408  in the deflated configuration. As inflatable member  408  is expanded, however, the two free ends of flexible circuit  501  will move apart from each other, and will continue to move apart until flexible circuit  501  contacts the inner surface of probe tip  222 . As shown in  FIG. 5G , flexible circuit  501  does not contact the inner surface of probe tip  222  over its hill circumference due to the expansion discussed above. The amount of contact, though, is still sufficient for preheating probe tip  222  as needed. 
         [0086]    Conventional assembly methods typically employ a single rigid heating element to preheat the probe tip. In many cases rigid heating element has a flat surface for affixing to the curved inner surface of the probe tip. Accordingly, to reduce the space between the flat surface of the rigid heating element and the curved inner surface of the probe tip, the affixing surface of the rigid heating element is minimized. This minimized surface area inefficiently preheats the probe tip, because the heat must radiate from the relatively small single rigid heating element surface area. Furthermore, the conventional assembly methods are typically manual, which results in imprecise duplication of heating element placement. 
         [0087]    In contrast, flexible circuit  220  of the present invention conformingly attaches to the inner surface of probe tip  216 , thus disposing heating element  202  over a large portion of the inner surface of probe tip  216 . The coil arrangement of heating element  202  allows for it to be in contact with much more surface area of the inner surface of probe tip  216  than the heating element of the prior art, and therefore it provides for more efficient preheating of probe tip  216 . In addition, because heating element  202  and temperature sensor  212  are disposed on flexible circuit  220  prior to insertion into probe tip  216 , the assembly method is much simpler. Furthermore, an assembly method in accordance with aspects of the present invention may be automated, which results in very imprecise duplication of heating element placement. 
         [0088]      FIG. 5H  illustrates another embodiment of the system in  FIG. 5F . 
         [0089]    As shown in  FIG. 5G , system  514  includes probe tip  222 , flexible circuit  501  and heat insulating material  516 . 
         [0090]    Heat insulating material  516  may include curable insulating materials, expandable insulating materials, or any other insulating materials that could be applied inside probe tip  222 , provided that the materials used do not erode or degrade the circuit assembly. 
         [0091]    Insulating material  516  serves multiple purposes. First, it may provide support to flexible circuit  501  to maintain contact between flexible circuit  501  and the inner diameter of probe tip  222 . Thus, if adhesive layer  502  failed at some point and no longer was able to keep flexible circuit  501  in contact with the inner surface of probe tip  222 , heat insulating material  516  would prevent flexible circuit  501  from losing contact with the inner surface of probe tip  222 . Second, heat insulating material  516  may help maintain probe tip  222  at a preheated temperature for a longer period of time, thus reducing the amount of power required to maintain the preheated temperature. 
         [0092]      FIG. 5I  illustrates a final assembly of a temperature sensing device in accordance with aspects of the present invention. 
         [0093]    As shown in the figure, system  518  includes flexible circuit  501 , probe tip  222 , and probe  104 . System  518  is also shown as including optional heat insulating material  516 . 
         [0094]    Probe  104  may be attached to probe tip  222  using standard joining methods, non-limiting examples of winch include adhesives, welding, soldering, mechanical fasteners, or any other joining method that would serve to connect probe  104  to probe tip  222  in a reliable and repeatable fashion. Probe  104  can then be attached to probe housing  102  (not shown) using standard attachment methods or mechanisms. 
         [0095]    As described above, temperature sensor  212  is located in probe tip  222 , however in other embodiments the temperature sensor is not required to be at the probe tip, thus further simplifying the assembly process. In some embodiments, the temperature sensor is an infrared thermal detector that may be located elsewhere in the assembly. The infrared thermal detector will be designed to detect the temperature of probe tip  222  by sensing the infrared radiation emitted from the inner surface of probe tip  222 . An example embodiment wherein the temperature sensor is not disposed at the probe tip will now be described in greater detail with reference to  FIG. 6 . 
         [0096]      FIG. 6  illustrates an alternate assembly configuration for a temperature sensing device in accordance with aspects of the present invention. 
         [0097]    As shown in the figure, system  600  includes probe housing  602 , infrared sensor  604 , probe  104 , probe tip  222 , heating element  206  and flexible circuit  606 . 
         [0098]    Probe housing  602  is very similar to probe housing  102  (not shown), however it includes a space in which to mount infrared sensor  604 . 
         [0099]    Infrared sensor  604  may be any standard infrared sensor that utilizes pyroelectric or ferroelectric materials, or that utilizes micro bolometer technology. 
         [0100]    Flexible circuit  606  is substantially similar to flexible circuit  501 , however it does not include a temperature sensor, it only includes heating element  206 , as the temperature sensor from flexible circuit  501  was replaced by infrared sensor  604 . 
         [0101]    In operation, when probe tip  222  is placed at the site where the temperature reading is desired, infrared sensor  604  would sense the temperature at probe tip  222  and relay the temperature to the display module (not shown). This configuration would further simplify the assembly process by eliminating the need to provide a temperature sensor as part of flexible circuit  606 . 
         [0102]    In prior art temperature sensing devices, the assembly method is tedious, time-consuming, and not particularly reliable or repeatable. The assembly method is dependent on skilled operators manually attaching a heating element and temperature sensor to the inner surface of a probe, which is akin to assembling a ship in a bottle. In addition, the heating element does not necessarily conform to the inner surface of the probe, reducing the heating efficiency by reducing the amount of surface area in which the heating element is in contact with the inner surface of the probe tip. 
         [0103]    The present invention provides several methods of assembling a temperature sensing device that overcomes the limitations of the prior art. The heating element and temperature sensor are disposed on the head portion of a flexible circuit base. This allows for the heating element to cover the majority of the head portion of the flexible circuit base, while the temperature sensor covers the remaining space of the head portion. The head portion of the flexible circuit base is then wrapped around an inflatable member and inserted into the probe tip. The inflatable member is then inflated, expanding the head portion of the flexible circuit base until the head portion conformingly attaches to the curved inner surface of the probe tip. The inflatable member is then deflated and removed, thus leaving the assembled probe tip ready for further operations to attach the tip to the rest of the temperature sensing device using standard methods. 
         [0104]    The assembly method in accordance with aspects of the present invention provides for more efficient, uniform preheating of the probe tip because the heating element is conformingly attached to the curved inner surface of the probe tip, thus providing a larger surface area for preheating. In addition, the method of using an inflatable member to attach the flexible circuit to the probe tip eliminates the need for highly skilled workers, and provides a much more reliable and repeatable process with which a temperature sensing device may be manufactured. 
         [0105]    The foregoing description of various preferred embodiments have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The example embodiments, as described above, were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.

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