referring now to fig7 , a block diagram is depicted , displaying the basic elements of one preferred embodiment of the present invention . enclosed within case 42 are implantable device 20 , which may further include pacing leads 24 or conduit 26 , battery 18 , and diode device 10 . the depicted assembly is implanted within a patient and utilizes a difference in temperature to generate power that can be harnessed for a wide range of devices and functions . among its many possible functions , this biothermally powered diode device can power a medical device that responds to various medical needs by providing drug delivery , electrical stimulation , or other forms of assistance . alternatively , nonmedical devices and other devices , could be provided with electrical energy . since the present invention utilizes a temperature differential to generate energy , it must be positioned at a location in the body where such a differential is available . a temperature gradient of up to 5 degrees c . can be found between the skin surface and the body core , and thus , placing the present invention beneath the skin and extending towards the body core is preferred . another possible configuration would be to have diode device 10 at a distance from case 42 and all it contains , but connected by means of a lead . as previously discussed , diode device 10 consists of a thermionic or themotunneling converter having two matching electrodes facing one another . voltage is created when there is a difference in temperature between the two surfaces of the device . it is preferred that diode device 10 be a thermionic or thermotunneling converter consisting of two silicon electrodes maintained at a desired distance from one another by means of spacers , as can be seen in fig1 . alternatively , a further preferred form of diode device 10 would be the thermionic vacuum diode device with adjustable electrodes in which the separation between the electrodes is set and controlled through the use of piezo - electric positioning elements that is depicted in fig2 through 4 , and as is disclosed in u . s . pat . no . 6 , 720 , 704 . an even further preferred form of diode device 10 would be to utilize the method described in u . s . patent app . no . 2005 / 0147841 for creating the electrodes in which indents and / or protrusions are etched into the wafer surface by means of laser , chemical , or other etching methods , as seen in fig5 and 6 . battery 18 functions as a storage element wherein voltage produced by the diode device can be stored . in times when leads 100 and 102 do not maintain a temperature difference and therefore do not produce any electrical current , the electrical energy stored within battery 18 can supply power to implantable device 20 . fig8 is a block diagram displaying the power generator of fig7 with the addition of elements that may be added , either independently or in combination , to enhance the functioning of the biothermal power generator . in the preferred embodiment depicted in fig8 , diode device 10 is connected to and provides electrical current to control circuit 14 through lead 12 . control circuit 14 , in turn , is operatively connected to voltage regulator 16 , which provides direct current to battery 18 . battery 18 , in turn , provides power to the implantable device 20 . alternatively , voltage regulator 16 could provide electrical current directly to implantable device 20 . if the temperature on a first surface of diode device 10 is higher than the temperature on the second surface of diode device 10 , then the polarity of the produced electric current produced will be the opposite of the situation than when the temperature of the first surface is lower than the temperature of the second surface . therefore , leads 12 may first communicate with polarity reverser 30 before they are connected with control circuit 14 . through the use of a polarity reversal device 30 , electrical current will effectively flow into control circuit 14 under all conditions of temperature . fig9 is a schematic of one preferred device of this invention in which some unnecessary details have been omitted for simplicity of illustration . in the preferred embodiment depicted in fig9 , the assembly 50 utilizes the diode device 10 , which may be any of the devices described in fig1 - 6 , generating electrical current from the temperature gradient between the internal body core 60 and the skin surface 62 . usually the body core temperature is greater than the skin surface temperature , but even in cases where this relationship is reversed , a control circuit 14 ( not shown , see fig8 ) will reverse the polarity of its voltage regulator so the battery can continue to be recharged . referring again to fig9 , the implant comprises a primary device 64 and a diode device 10 . primary device 64 is comprised of the implantable device 20 and all elements enhancing the implantable device such as those depicted in fig8 , with the exception of the diode device 10 . encompassing primary device 64 is a case 42 , which provides a hermetic seal around all the entire apparatus while allowing for the passage of wires without breaching the hermetic seal , and has specialized thermal properties that can be achieved by the usage of precise combinations of a variety of materials and fabrication methods . depending on the desired result , properties such as strength , durability , high thermal conductivity , biocompatibility , magnetic impermeability , and flexibility can be built into the case . preferably , the diode device 10 is situated immediately against the case 42 and is in thermal contact therewith . the entire assembly is disposed close to the skin surface , and the case 42 may or may not be in direct contact with the skin . in a preferred embodiment , a layer of gel or polymer 68 is planted directly above the device case 42 and is contained within a conductive sealing membrane 70 . both gel 68 and membrane 70 provide a highly thermally conductive path from the device case 42 to the skin surface 62 as well as creating a greater degree of comfort for the patient . another feature that may be added to assembly 50 to thermally isolate it from the surrounding environment is an insulating sheath . in fig9 , and the preferred embodiment depicted therein , insulating sheath 72 surrounds primary device 64 and is made preferably of a flexible polymeric insulating material . one benefit of assembly 50 being disposed immediately below the skin surface is the capacity for heat to be added or removed from one side of the diode device through the use of an external hot ( or cold ) source . by way of example , a patient could apply an ice pack or a warming apparatus to the skin surface directly above the implanted medical device , creating a greater temperature differential between the two surfaces of the diode device , and thus providing increased electrical current to the implantable device . in this way , a patient could ensure a plentiful supply of electrical current to the implanted device regardless of the ambient temperature . fig1 is a schematic of another preferred design of assembly 50 . like fig9 , it generates electrical current through the temperature differential between the body core and the skin surface . many of the components are similar in design and function to the corresponding components described in fig9 . however , in this preferred embodiment , gel / polymer 68 and its membrane 70 have been removed , and device case 42 is now in direct contact with the skin . furthermore , an inward facing portion of the device 50 has been extended towards the body core 60 to enhance current generation by contacting a region with a greater average temperature . a conductive rod 74 , which may be a rod or heat pipe , extends from the diode device 10 towards the body &# 39 ; s center and ends in a thermal contact 76 . the insulating sheath 72 of fig8 has been extended along the length of rod 74 , maintaining thermal isolation from the surrounding body tissue . the design depicted in fig9 is meant to provide for a greater temperature differential , and thus a greater current generation . there exist a multiplicity of variations for the positioning , size , and comfort of the implant that may or may not make use of design features such as a conformable gel or polymer between the device and the skin , insulating sheath , conductive plates and other electrical features that will be obvious to those skilled in the art . fig1 is a further preferred embodiment of the present invention in which the diode device is placed at a distance from the implantable circuitry to which it provides power . an advantage of such a configuration is that the diode device could be positioned at a location that provides the greatest possible temperature gradient while the circuitry it powers could be positioned at a second location that provides for greater comfort , ease of installation , repair , and monitoring , or other advantages . in fig1 , diode device 10 is connected to primary device 64 via electrically conducting lead 104 . while this invention has been described with reference to numerous embodiments , it is to be understood that this description is not intended to be construed in a limiting sense . it will be obvious to persons skilled in the art that the biothermal power generation process described herein encompasses numerous embodiments in which there are changes in the details of the present invention and additional embodiments of the present invention will be apparent to , and may be made by , persons of ordinary skill in the art having reference to this description . it is to be understood that all the embodiments described above can be utilized in any possible combination . it is contemplated that all such changes and additional embodiments are within the spirit and true scope of the invention as claimed below .
an implantable assembly is disclosed comprising a diode device charging assembly having the means for transferring thermal energy from a living organism to a diode device , means for creating electrical energy from said thermal energy , and means for charging an implantable device with said electrical current . the diode device of this invention is a thermotunneling or thermionic converter . in a preferred embodiment the electrodes of the diode device have been modified to reduce their work function by through the addition a periodically repeating structure comprised of one or more indentations of the dimensions so as to create de broglie wave interference , leading to a change in electron work function . the implantable assembly utilizes a temperature difference in a body to efficiently generate energy to be harnessed by a wide range of devices .