Size-constrained device faraday cage

Abstract

This specification relates to devices, such as computing devices that may include size-constrained shielded circuit board assemblies. One example may include a circuit board comprising an upwardly extending enclosure. The example may also include a heating element positioned within the enclosure and a thermal module positioned above the heating element, defining a primary planar surface. The thermal module may include a downwardly extending frame overlapping the enclosure. A gasket may be compressed between the enclosure and the frame in a direction parallel to the primary planar surface.

Description

Background Technology

[0001] This description relates to a size-constrained device with a heat-generating component, and to cooling the heat-generating component while providing electromagnetic shielding (e.g., RF shielding). Attached Figure Description

[0002] The accompanying drawings illustrate the implementation of the concepts conveyed herein. The features of the illustrated implementations can be more readily understood by referring to the following description in conjunction with the accompanying drawings. Where feasible, the same reference numerals in the drawings are used to refer to the same elements. Furthermore, the leftmost numeral of each reference numeral conveys the drawing in which that reference numeral was first introduced and the associated discussion.

[0003] Figure 1 It may include a partial cross-sectional perspective view of an example device implemented with a size-constrained shielded circuit board assembly according to the concept of the present invention.

[0004] Figures 2A-2D yes Figure 1 An exploded perspective view of the various parts of a size-constrained shielded circuit board assembly.

[0005] Figure 2E yes Figure 1 A perspective view of a portion of a sample size-restricted shielded circuit board assembly.

[0006] Figure 2F and 2G Is it like this? Figure 2E The diagram shows a cross-sectional view of a portion of an example dimension-constrained shielded circuit board assembly.

[0007] Figure 3 and 4 This is a cross-sectional view of an example of a replacement size-constrained shielded circuit board assembly according to some implementations of the concept of the present invention.

[0008] Figure 5 This is an exploded perspective view of an example of a replacement size-constrained shielded circuit board assembly according to some implementations of the concept of the present invention.

[0009] describe

[0010] This invention relates to devices, such as computing devices. For many form factors (such as tablets, laptops, and / or wearable devices), consumer preferences lean towards smaller form factors, particularly thinner (e.g., z-size limitations) and / or lighter form factors. Simultaneously, consumers desire high performance from computing resources (e.g., heat-generating components) (such as processing resources, memory resources, battery resources, etc.). High performance often results in unwanted heat generation from these heat-generating components. This heat can be dissipated via thermal modules that can be positioned near the heat-generating components. The heat-generating components are also shielded from environmental radio frequency energy (RF shielding) that could degrade their performance. Furthermore, RF emissions (e.g., RF noise) from the heat-generating components can be blocked so that they do not interfere with other device components (such as various antennas). In other words, this invention can relate to RF shielding in two directions (e.g., from and toward the heat-generating components).

[0011] The present invention can employ components in a device that contribute to both the positioning of the thermal module and the heating element, as well as to the RF shielding of the heating element. These components can save space in thin form factor devices in the z-dimension, among other advantages. These components can also provide a reduced z-dimension by eliminating other components that contribute to the z-height. Traditionally, a cover is placed above the thermal module to offset the heating element. The present invention eliminates the cover, thereby reducing thickness, cost, and / or complexity. In some cases, the components also contribute to the repairability of the device (e.g., easier assembly and disassembly). These and other aspects are described below.

[0012] Figure 1 A partial cross-sectional view of an example device 100, representing a tablet-type computing device, is shown. In this representation, device 100 may include a size-constrained, shielded, and cooled circuit board assembly 102 (hereinafter referred to as the "circuit board assembly"), which in this example is contained within a housing 104 and a display 106. The circuit board assembly 102 may be employed in other device scenarios.

[0013] Figure 2A-2G Together, they illustrate the features of the circuit board assembly 102. Figures 2A-2D An exploded view of the circuit board assembly 102 is shown. Figure 2E A partial assembly diagram of the circuit board assembly 102 is shown. Figure 2F and 2G This is a view of a portion of the circuit board assembly 102.

[0014] The circuit board assembly 102 may include a circuit board 202, a heat-generating component 204, a thermal module 206, a frame 208, a fence 210, and a gasket 212. The circuit board 202 may be a printed circuit board (PCB) or a flexible printed circuit (FPC), etc. The heat-generating component 204 may be positioned on the circuit board 202. The heat-generating component may be a processor 214, such as a central processing unit (CPU), a graphics processing unit (GPU), and storage / memory, a battery, and / or a converter, etc. As will be explained in more detail below, the circuit board 202, thermal module 206, frame 208, fence 210, and / or gasket 212 may form a Faraday cage 216 (e.g., RF shielding) surrounding the heat-generating component 204.

[0015] The circuit board 202 may include a fence 210 extending upward toward the thermal module 206. From one angle, the fence 210 may define a first perimeter 218, and the heat-generating component 204 may be located within the first perimeter 218.

[0016] The thermal module 206 may be manifested as a vapor chamber, heat pipe, radiator, heat sink, and / or sheet of conductive material (such as copper or graphite), among other configurations. The thermal module 206 may include a frame 208 extending downward toward the circuit board 202. The frame 208 may be an integrated portion of the thermal module. For example, the thermal module 206 having the frame 208 may be formed by additive manufacturing processes (such as 3D printing) or by subtractive manufacturing processes (such as machining). Alternatively, the frame 208 may be a separate component attached to the thermal module 206. For example, the frame may be welded, soldered, and / or otherwise fused (e.g., fixed) to the thermal module.

[0017] From one perspective, frame 208 can define a second perimeter 220. The first perimeter 218 and the second perimeter 220 can be different, such that frame 208 can be contained within fence 210, or vice versa (e.g., they bypass each other rather than be adjacent to each other). In other words, the first and second perimeters (218 and 220) can be offset from each other, and frame 208 and fence 210 can partially overlap in the z-dimensional.

[0018] Note that this implementation includes port 221 passing through frame 208. Figure 2A ), gasket 212 and fence 210, to allow the second thermal module 206(1)( Figure 2A The heat is thermally coupled to the heat module 206. The heat module 206(1) can be used to dissipate heat energy to areas of the device not covered by the heat module 206. Figure 5 Another implementation is shown that does not include port 221.

[0019] Frame 208 can provide structural integrity to thermal module 206. For example, thermal module 206 can have generally opposite principal planar surfaces 222 in the xy dimension. Figure 2A ) and 224 ( Figure 2C Frame 208 can provide structural integrity that contributes to maintaining the planarity of the primary planar surfaces 222 and 224 of the thermal module 206. This allows for the use of thinner thermal modules (in the z-reference direction) without them experiencing deformation during and / or during assembly. For example, fastener 226 can be used to bias the thermal module 206 against the heat-generating components without deforming the planar nature of the thermal module 206. Thus, frame 208 contributes to a device that is thinner overall in the z-dimensional direction.

[0020] Furthermore, this invention is more practical than conventional designs. In conventional designs, the thermal module is often damaged if the device is disassembled. In the illustrated configuration, fastener 226 can be removed and the thermal module 206 can be removed without damage, thanks in part to the structural support provided by frame 208. It is likely that no components will be damaged and repairs can be performed, and circuit board assembly 102 can be reassembled. Damage that is unlikely to occur often occurs at the gasket 212. Gasket 212 is a relatively simple and inexpensive component, often costing at least an order of magnitude less than the thermal module. Replacement gasket 212 can be installed on fence 210, and reassembly of circuit board assembly 102 can be completed.

[0021] In this configuration, the thermal module 206 can be positioned against the heating element 204 (either in direct contact or via an intervening thermal interface material). The thermal module 206 can also be close to the enclosure 210. In this implementation, a gasket 212 can be positioned between the enclosure 210 and the thermal module 206. However, this implementation does not rely on the gasket 212 sealing the enclosure 210 and the thermal module 206 (e.g., completing the Faraday cage 216). Alternatively, the gasket 212 can seal the Faraday cage 216 between the frame 208 and the enclosure 210 (e.g., eliminating RF leakage). For example, the gasket 212 can offset the frame 208 and the enclosure 210 away from each other in the x and y dimensions. For example, the gasket 212 can be compressed between the frame 208 and the enclosure 210 in the x and y dimensions and apply offset against the frame and enclosure in the x and y dimensions. In other words, the offset created by the gasket 212 can be parallel to the principal planar surfaces 222 and 224. The offset created by gasket 212 from frame 208 and fence 210 ensures adequate contact to avoid RF leakage between gasket 212 and frame 208 and / or between gasket 212 and fence 210.

[0022] Because the seal of the Faraday cage 216 is created by the gasket 212 abutting against the frame 208 and the fence 210, dimensional variations in the z-axis can be accommodated. For example, fastener 226 can be tightened until the thermal module 206 contacts the heating element 204. Recall that the fence 210 and the frame 208 bypass each other so that variations in specified dimensions (e.g., design tolerances) from the heating element 204 and the thermal module 206 can be accommodated. This accommodation is achieved because the inventive concept does not rely on z-dimensional contact between the frame 208, the fence 210, and the gasket 212 to seal the Faraday cage 216. Instead, xy-dimensional contact between the frame 208, the gasket 212, and the fence 210 seals the Faraday cage 216 independently of z-dimensional variations.

[0023] In some implementations, washer 212 may include offset feature 228 that creates an offset between frame 208 and fence 210. In this case, offset feature 228 manifests as angled teeth 230. Figure 2A The gap 232 between adjacent teeth 230 Figure 2A This affects which wavelengths of the RF signal are blocked by the Faraday cage 216. The bias feature may include other configurations. For example, the bias feature may be sinusoidal (e.g., extending in the y-reference direction for the amplified portion and alternating in the +x and -x reference directions). In some configurations, the washer 212 may include an alignment feature 234, which facilitates holding the washer 212 relative to the fence 210 and / or frame 208 during assembly.

[0024] The heating element 204 may be located within the first and second boundaries 218 and 220 and in the volume 235 between the circuit board 202 and the thermal module 206. Figure 2B and 2G Within. The volume 235 provided by employing the concept of the present invention can be larger than the volume of a conventional design for a given z-dimensional height. For example, the frame 208 and the fence 210 can be considered to have a “picture frame” configuration (e.g., no central boundary or perimeter). The picture frame configuration can allow the heating component 204 to be positioned within the width W defined by the vast majority of the inward orientation of the frame 208 and / or the fence 210. Figure 2G The volume defined as 235 is mostly at a height H ( Figure 2G The circuit board 202 extends to the thermal module 206. The increased volume 235 allows more and / or larger heating elements 204 to be positioned in contact with the thermal module 206 within the Faraday cage 216, but provides a reduced overall size in the z-dimensional dimension by removing the cover used in conventional designs to force the thermal module against the heating elements.

[0025] In this scenario, as mentioned above, the heat-generating component 204 manifests as a processor 214, such as a central processing unit (CPU) and / or a graphics processing unit (GPU). Alternatively or additionally, the heat-generating component may include various communication circuitry systems, such as USB circuitry, Bluetooth circuitry, Wi-Fi circuitry, 4G circuitry, 5G circuitry, various electronic circuitry systems, storage and / or batteries, etc. Some implementations may utilize fences, frames, and gaskets to isolate individual heat-generating components from each other and from external RF energy. The following is about... Figure 5 An example of this type is described.

[0026] Figure 2D and 2E The various parts of the circuit board assembly 102 are shown. Figure 2D It is an exploded perspective view, and Figure 2E It is a similar perspective view with thermal module 206 removed. Figure 2E The alignment feature 234(2) of the washer is shown interacting with the fence 210. This interaction can keep the washer 212 aligned with the fence 210, and / or can keep the washer assembled with the fence (e.g., preventing the washer from popping out of the fence during the assembly process). Figure 2F and 2G Is it like this? Figure 2E The diagram shows a cross-sectional view of the circuit board assembly 102 indicated in the figure. Figure 2G Similar to Figure 2F However, a magnified view of a portion of the circuit board assembly is shown.

[0027] As mentioned above, circuit board 202 can contribute to Faraday cage 216 (e.g., the bottom of Faraday cage 216). This aspect is... Figure 2F and 2G As can be seen in the image. In this scenario, circuit board 202 may include a conductive structure 236. The conductive structure 236 may be positioned below the heating element 204. In this example, the conductive structure 236 is on the bottom surface of circuit board 202 (e.g., on the side opposite to the heating module 206). The conductive structure 236 may be electrically coupled to fence 210 via one or more conductors 238 passing through circuit board 202. The conductive structure 236 may also be electrically connected to device ground 240. Figure 2F Therefore, conductive structure 236 and conductor 238 contribute to Faraday cage 216 as part of circuit board 202. In this case, conductive structure 236 is an additional layer on the bottom surface of circuit board 202. In other cases, conductive structures may be incorporated into the circuit board, such as conductive particle layers being mixed into circuit board material layers.

[0028] Compared to Figure 2A-2GThe implementation of the explanation can be thinner in the z-dimensional than existing designs, can use fewer components, allows more lateral space in the x and / or y-dimensional for the heating components within the Faraday cage, and / or can be easily assembled and disassembled.

[0029] Figure 3 and 4 Replacement circuit board assemblies 102A and 102B are shown respectively. (The suffixes 'A' and 'B' indicate that some aspects of these circuit board assemblies differ from those of the circuit board assembly 102 described above and / or differ from each other.) Figure 2A-2G For the sake of brevity, the components described here will not be repeated.

[0030] Figure 3 A circuit board assembly 102A is shown, in which a gasket 212 can be frictionally fitted onto a fence 210. A frame 208 (previously fixed to a thermal module 206) can be forced onto the gasket and fence to “load” the gasket 212. For example, the gasket 212 may be formed of a resilient or elastic material (such as spring steel or other conductive materials). Forcing the frame onto the gasket compresses the gasket in the x-axis in this view (and similarly in the y-axis). The elasticity of the gasket 212 can then create an outward bias against the frame 208 and fence 210 in the x-axis. This bias ensures consistent contact between the gasket 212, the frame 208, and the fence 210 to seal the Faraday cage 216.

[0031] Figure 4 Another example circuit board assembly 102B is shown. In this implementation, a washer 212 is frictionally fitted onto the vertical portion 402 of the frame 208. The washer 212 does not extend beyond the fence 210 (e.g., between the fence and the frame in the z-reference dimension). In other words, the washer 212 does not extend along the horizontal portion 404 of the frame 208.

[0032] In this configuration, gasket 212 may be represented as a split tube (extending into and out of the drawing in this cross-sectional view along the y-reference direction) or other shape factor. Frame 208 and / or gasket 212 may include alignment features to facilitate maintaining the gasket in its intended position on the frame. In this configuration, frame 208 includes an alignment feature 406 in the form of a shallow recess in which the split tube can be positioned. The split tube may be formed of a resilient material such that the (circular) portion of the tube positioned between fence 210 and frame 208 serves as a biasing feature 228. Biasing feature 228 can generate forces against fence 210 and frame 208 in the x and y dimensions, which ensures consistent contact between fence and frame and thus ensures an RF seal, while the gasket does not occupy space in the z dimension (such as between fence 210 and frame 208 or between fence 210 and thermal module 206).

[0033] Figure 5 Replacement circuit board assembly 102C is shown. (The suffix 'C' indicates that some aspects of this circuit board assembly differ from those of the circuit board assemblies 102, 102A, and / or 102B described above.) Figure 2A-2G For the sake of brevity, the components described in 3 and / or 4 will not be repeated here.

[0034] The circuit board assembly 102C is capable of shielding multiple heat-generating components 204 from both external RF energy and RF energy between them. In this case, the first perimeter 218 formed by the fence 210 may include multiple first perimeters (218(1), 218(2), and 218(3)): one surrounding heat-generating component 204(1); one surrounding heat-generating component 204(2); and one surrounding heat-generating component 204(3). Similarly, the second perimeter 220 formed by the frame 208 includes multiple second perimeters (220(1), 220(2), and 220(3)): one surrounding heat-generating component 204(1); one surrounding heat-generating component 204(2); and one surrounding heat-generating component 204(3). The multiple first and second perimeters (218 and 220) contribute to the Faraday cage 216 surrounding each of the individual heat-generating components 204(1)-204(3).

[0035] Individual Faraday cages 216(1)-216(3) provide RF shielding to individual heating components 204(1)-204(3) to protect them from RF energy between them and from external RF energy (such as that generated by an unshielded heating component 204(4)). This RF shielding can be considered bidirectional (e.g., protecting the heating components within the Faraday cage from external RF energy and protecting other heating components and / or other external components from RF energy generated by the heating components within the Faraday cage). This RF shielding can maintain the above-mentioned... Figure 2A-4 The described reduced z-size and / or increased internal volume (e.g., shielded volume) are achieved simultaneously.

[0036] In the described implementation, frame 208, fence 210, and / or gasket 212 may be made of conductive materials, such as composite materials or various metals (e.g., copper or stainless steel). In some cases, the gasket may have elastic properties, such as being provided by spring steel and other materials.

[0037] This size-constrained shielded circuit board assembly concept can be used in various types of devices, such as computing devices, including but not limited to laptops, tablets, smartphones, wearable smart devices, gaming devices, entertainment consoles, and / or other types of devices under development or in the pipeline. As used herein, a computing device can be any type of device with some processing power and / or storage capacity and / or other heat-generating components. A mobile computing device can be any computing device designed for convenient carrying by a user.

[0038] Various examples have been described above. Additional examples are described below. One example includes a device comprising: a circuit board including an upwardly extending fence defining a first perimeter; a heating element positioned within the first perimeter; a thermal module positioned above the heating element including a downwardly extending frame defining a second perimeter distinct from the first perimeter; and a gasket that creates a bias between the fence and the frame, the bias contributing to blocking radio frequency energy between the fence and the frame to complete a Faraday cage around the heating element.

[0039] Another example may include any of the above and / or the following examples, wherein the circuit board further includes a conductive structure positioned below the first perimeter and electrically coupled to the fence.

[0040] Another example may include any of the above and / or the following examples, wherein the conductive structure is incorporated into the circuit board or wherein the conductive structure is external to the circuit board.

[0041] Another example may include any of the above and / or the following examples, wherein the conductive structure, fence, frame, gasket, and thermal module form a Faraday cage surrounding the heat-generating component.

[0042] Another example may include any of the above and / or the following examples, wherein the heat-generating components include the processor and / or memory.

[0043] Another example may include any of the above and / or the following examples, wherein the thermal module includes a steam chamber, heat pipe, radiator or heat sink.

[0044] Another example may include any of the above and / or the following examples, wherein the thermal module includes a flat surface, and wherein the bias is generally parallel to the flat surface (e.g., at + / -30 degrees to the flat surface).

[0045] Another example may include any of the above and / or the following examples, wherein the gasket extends between the fence and the thermal module, or wherein the gasket does not extend between the fence and the thermal module.

[0046] Another example may include any of the above and / or the following examples, wherein the gasket is at least partially made of metal.

[0047] Another example may include any of the above and / or the following examples, wherein the washer is made of spring steel.

[0048] Another example may include any of the above and / or the following examples, wherein the heating component includes a plurality of heating components, and wherein the first perimeter defined by the fence includes a plurality of first perimeters, and wherein an individual heating component is located within an individual first perimeter.

[0049] Another example may include any of the above and / or the following examples, wherein the frame defines a plurality of second perimeters, and wherein the plurality of first perimeters, the plurality of second perimeters and the gaskets form a plurality of Faraday cages surrounding the plurality of heating components, such that the individual heating components shield each other.

[0050] Another example includes a device comprising a circuit board including an upwardly extending fence; a heating element positioned within the fence; a thermal module defining a principal planar surface positioned above the heating element, the thermal module including a downwardly extending frame overlapping the fence; and a gasket compressed between the fence and the frame in a direction parallel to the principal planar surface.

[0051] Another example may include any of the above and / or the following examples, wherein the circuit board, thermal module, fence, frame and gasket form a Faraday cage surrounding the heat-generating component.

[0052] Another example may include any of the above and / or the following examples, wherein the washer is sinusoidal in shape between the frame and the fence, or wherein the washer includes a plurality of teeth extending between the frame and the fence.

[0053] Another example may include any of the above and / or the following examples, wherein the gasket extends between the fence and the thermal module, or wherein the fence contacts the thermal module.

[0054] Another example may include any of the above and / or the following examples, wherein the washer includes an alignment feature to keep the washer aligned with the fence, and / or wherein the washer includes an alignment feature to keep the washer aligned with the fence and the frame.

[0055] Another example may include any of the above and / or the following examples, where the frame provides structural integrity to the thermal module to maintain the planarity of the main planar surface.

[0056] Another example includes a device comprising a circuit board including an upwardly extending fence; a heating element positioned within the fence; a thermal module positioned above the heating element including a downwardly extending frame offset from the fence; and a gasket extending between the fence and the frame but not above the heating element.

[0057] Conclusion

[0058] Although techniques, methods, apparatuses, systems, etc., relating to size-constrained shielded circuit board assemblies have been described using language specific to structural features and / or methodological actions, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described. Rather, these specific features and actions are disclosed as examples of implementing the claimed methods, apparatuses, systems, etc.

Claims

1. An apparatus comprising: A circuit board extending along a first horizontal plane, the circuit board including a fence extending upward from the first horizontal plane defining a first perimeter; Heating components located within the first perimeter; A thermal module positioned above the heating element, the thermal module including a frame defining a second perimeter different from the first perimeter and extending downward to the first horizontal plane, such that the frame overlaps with the fence and a space exists between the overlapping frame and the fence; as well as A washer not belonging to the fence or the frame, the washer extending parallel to a second horizontal plane between the fence and the frame and being compressed between the fence and the frame to create an offset parallel to the second horizontal plane and forcing the washer against the fence and the frame to fill the space, thereby blocking radio frequency energy between the fence and the frame to complete a Faraday cage around the heating component.

2. The device of claim 1, wherein the circuit board further includes a conductive structure positioned below the first perimeter and electrically coupled to the fence.

3. The device of claim 2, wherein the conductive structure is integrated into the circuit board, or wherein the conductive structure is external to the circuit board.

4. The device of claim 2, wherein the conductive structure, the enclosure, the frame, the gasket, and the thermal module form the Faraday cage surrounding the heating component.

5. The device of claim 1, wherein the heat-generating component includes a processor and / or a memory.

6. The device of claim 1, wherein the thermal module comprises a steam chamber, a heat pipe, a radiator, or a heat sink.

7. The device of claim 1, wherein the thermal module includes a flat surface, and wherein the bias is parallel to the flat surface.

8. The device of claim 7, wherein the gasket extends between the fence and the thermal module, or wherein the gasket does not extend between the fence and the thermal module.

9. The device of claim 1, wherein the gasket is at least partially made of metal.

10. The device of claim 9, wherein the washer is made of spring steel.

11. The device of claim 1, wherein the heating component comprises a plurality of heating components, and wherein the first perimeter defined by the fence comprises a plurality of first perimeters, and wherein an individual heating component is positioned within an individual first perimeter.

12. The device of claim 11, wherein the frame defines a plurality of second perimeters, and wherein the plurality of first perimeters, the plurality of second perimeters, and the gasket form a plurality of Faraday cages surrounding the plurality of heating components such that individual heating components shield each other.

13. An apparatus comprising: A circuit board extending along a first horizontal plane, the circuit board including a fence extending upward from the first horizontal plane; The heating element is fixed within the enclosure relative to the circuit board; A thermal module defining a main planar surface, the thermal module being parallel to the first horizontal plane and offset against the heating component to form a heat receiving relationship, the thermal module including a downwardly extending frame overlapping the fence, such that a space exists between the overlapping frame and the fence; as well as A washer that is not part of the fence or the frame, the washer extending parallel to a second horizontal plane between the fence and the frame and being compressed between the fence and the frame to create an offset parallel to the second horizontal plane and forcing the washer against the fence and the frame to fill the space, thereby preventing radio frequency energy from passing between the fence and the frame.

14. The device of claim 13, wherein the circuit board, the thermal module, the enclosure, the frame, and the gasket form a Faraday cage surrounding the heating component.

15. The device of claim 13, wherein the washer is sinusoidal between the frame and the fence, or wherein the washer comprises a plurality of teeth extending between the frame and the fence.

16. The device of claim 13, wherein the gasket extends between the fence and the thermal module, or wherein the fence contacts the thermal module.

17. The device of claim 13, wherein the washer includes an alignment feature to keep the washer aligned with the fence, and / or wherein the washer includes an alignment feature to keep the washer aligned with the fence and the frame.

18. The device of claim 13, wherein the frame provides structural integrity to the thermal module to maintain the planarity of the primary planar surface.

19. An apparatus comprising: A circuit board extending along a first horizontal plane, the circuit board including a fence extending upward from the first horizontal plane; The heating element is fixed within the enclosure relative to the circuit board; A thermal module parallel to the first horizontal plane and offset against the heating component to form a heat receiving relationship, the thermal module including a downwardly extending frame offset from the fence, such that the frame overlaps with the fence and a space exists between the overlapping frame and the fence; as well as A gasket extending parallel to a second horizontal plane between the fence and the frame but not above the heating element, the gasket not belonging to the fence or the frame and being compressed between the fence and the frame to create an offset parallel to the second horizontal plane and forcing the gasket against the fence and the frame to fill the space, thereby blocking radio frequency energy between the fence and the frame to complete a Faraday cage around the heating element.

20. The device of claim 19, wherein the thermal module is positioned on the heating element in direct contact with the heating element, and wherein the thermal module is biased directly toward the heating element without a cover.

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