Thermal Interface Device

Abstract

A thermal interface device for a heater system configured to form a thermal interface with an object (20) to be heated comprises a support structure (14) and an interface assembly (12) attached to the support structure (14). The interface assembly (12) has an interface member (16) configured to engage the object (20) to form a thermal interface, and a biasing member (18) between the support structure (14) and the interface member (16) that, in use, functions to bias the interface member (16) away from the support structure (14) and into engagement with the object (20). The biasing member (18) comprises a thermally insulating material and is configured to resist heat transfer from the interface member (16) to the support structure (14). The interface member (16) may comprise a thermally conductive layer (30, 36) supported on a rigid substrate layer (34), the thermally conductive layer (30, 36) may cover at least a majority of a surface area of ​​the rigid substrate layer (34).

Description

[Technical field]

[0001] The present invention relates to a thermal interface device and a heater system comprising such a device, in particular, but not exclusively, the present invention relates to a thermal interface device and associated interface elements for a heater system for heating biological samples in a diagnostic device. [Background technology]

[0002] Diagnostic devices that process biological samples, such as point-of-care (PoC) devices configured to detect nucleic acids indicative of pathogens, often require heating of the sample. For example, devices that perform a polymerase chain reaction (PCR) process thermally cycle the sample to amplify the genetic material to be detected. Other devices use isothermal methods, such as loop-mediated isothermal amplification (LAMP), to amplify the genetic material by heating the sample at a constant temperature. Also, it is often necessary to heat the sample at different temperatures during different stages of the test, typically resulting in multiple localized heating points as the sample moves through the device during the testing process.

[0003] To obtain accurate and reliable results, heating must be precise and substantially uniform for each sample over the course of successive tests. It is also important that the samples are heated efficiently, especially in portable devices which may be battery powered.

[0004] To avoid contamination of device components, some configurations include placing the sample in a disposable test cartridge that is docked into the device. The device then processes the sample contained in the cartridge while avoiding direct contact with the sample, and once the test is complete, the cartridge and the sample contained therein can be disposed of. The device is then ready to use to perform the next test without the need for cleaning.

[0005] Disposable test cartridges may be configured to be passive in the sense that they do not include electronic components, thereby reducing costs and facilitating disposability. In such a configuration, the main device includes a heating component configured to transfer heat to a sample in a docked cartridge. The accuracy, speed, and efficiency of the heating achieved in the sample depend on the properties of the thermal interface formed between the heating component and the test cartridge. Notably, such an interface is not permanent, but is formed each time a new cartridge is docked to the device. To achieve efficient heat transfer to each new cartridge throughout successive test steps, robust and complete contact at the thermal interface between the cartridge and the heating component needs to be created in a reproducible and reliable manner.

[0006] One known solution is to provide the exterior of each test cartridge with a copper plate that is heated by the main device and thus acts as a thermal interface plate that can transfer heat to the sample in the cartridge. The copper plate may be heated using a non-contact method, for example by radiatively heating the plate using LEDs in the device. Due to its high thermal conductivity, the copper plate distributes heat evenly across the interface with the cartridge, thus allowing the sample to be heated substantially evenly. Summary of the Invention [Problem to be solved by the invention]

[0007] However, the copper plate is an additional component in the test cartridge, thus increasing the cost of the cartridge, and the copper plate must be securely attached to the cartridge housing, typically with an adhesive, to create the necessary thermal interface, which adds manufacturing steps and therefore costs.

[0008] It is against this background that the present invention has been made. [Means for solving the problem]

[0009] One aspect of the invention provides an interface element for a heater system, for example a heater system of a diagnostic device. The interface element is configured to form a thermal interface with an object to be heated by the heater system. The element comprises an interface member configured to engage the object. The interface member has a thermally conductive layer supported on a rigid substrate layer, the thermally conductive layer covering at least a majority of a surface area of ​​the rigid substrate layer. The interface element further comprises at least one flexible biasing member connected to and extending therefrom, and optionally a set of such biasing members. The biasing member is configured to bias the interface member into engagement with the object in use. The biasing member comprises a thermal insulator and is configured to resist escape of heat from the interface member.

[0010] The substrate layer may be disposed between a pair of conductive layers, in which case the interface member may include a thermal link, such as a thermal via, extending between the conductive layers.

[0011] The interface member may comprise a rigid substrate layer and a flexible substrate layer, in such an embodiment, the biasing member may be constructed of the same material as the flexible substrate layer of the interface member and may be continuous with the flexible substrate layer.

[0012] The conductive layer may be divided into multiple heat conducting regions separated by thermally insulating regions, if desired, to allow, for example, each region to be heated to a different temperature.

[0013] The interface element may include a conductive path extending on the interface member along the length of the biasing member, such a path may allow power to be supplied to components provided on the interface member, such as a temperature sensor.

[0014] Preferably, the interface element may be formed as a rigid-flex printed circuit board, such that the interface element may be manufactured by a printed circuit board (PCB) manufacturer using conventional materials and processes.

[0015] A set of biasing members may be disposed about the interface member, the biasing members may be equally spaced about the interface member and may extend perpendicularly from or tangent to an edge of the interface member.

[0016] The interface element may have at least one axis of symmetry and / or at least one degree of rotational symmetry. Each axis of symmetry or degree of symmetry may extend, for example, through each biasing member. The interface element may have an axis of symmetry and / or degree of symmetry corresponding to each biasing member.

[0017] Another aspect of the invention provides a thermal interface device for a heater system, for example a heater system of a diagnostic device. The thermal interface device is configured to form a thermal interface with an object to be heated by the heater system. The device comprises a support structure and an interface assembly attached to the support structure. The interface assembly has an interface member configured to engage the object to form a thermal interface, and a biasing member between the support structure and the interface member, the biasing member functioning in use to bias the interface member away from the support structure and into engagement with the object. The biasing member comprises a thermal insulator and is configured to resist heat transport from the interface member to the support structure.

[0018] The interface assembly of the thermal interface device may be defined by an interface element, such as an interface element of any of the aspects described above.

[0019] In the thermal interface device or element described above, the insulating material may represent at least half the volume of the biasing member, which may consist predominantly of insulating material.

[0020] The biasing member may be integrally formed with the interface member.

[0021] The interface member may be divided into multiple heating zones, separated by insulation, if desired, allowing the multiple heating zones to be heated to different temperatures, which may be useful, for example, when the zones contact areas of an object corresponding to different test process steps that require different heating regimes.

[0022] The thermal interface device may include a temperature sensor, e.g., a PT100 or PT1000, configured to generate a signal indicative of a temperature of the interface member. The temperature sensor may be attached to the interface member, in which case the biasing member may have a conductive path connected to the temperature sensor and extending to the support structure.

[0023] The support structure may include a circuit board.

[0024] The thermal interface device may include a number of interface assemblies mounted to a support structure.

[0025] The interface assembly may include a plurality of biasing members operating between the support structure and the interface member. The biasing members of the interface assembly may have substantially the same length. The biasing members may be equally spaced around the interface member and may extend substantially perpendicular to or tangent to an edge of the interface member.

[0026] In some embodiments, the interface member comprises a thermally conductive material that may cover at least a majority of the surface area of ​​the interface member. The interface member of the interface assembly may comprise a thermally conductive layer supported on a rigid substrate layer, the thermally conductive layer covering at least a majority of the surface area of ​​the rigid substrate layer. The substrate layer may be disposed between a pair of conductive layers, in which case the interface member may have a thermal link extending between the conductive layers. The interface member may optionally comprise a rigid substrate layer and a flexible substrate layer. The biasing member may be constructed of the same material as the flexible substrate layer of the interface member. The biasing member may be continuous with the flexible substrate layer of the interface member. The interface assembly may be formed as a rigid-flex printed circuit board.

[0027] The interface assembly may have at least one axis of symmetry and / or at least one degree of rotational symmetry.

[0028] In the interface element or thermal interface device described above, the biasing members may have substantially the same length and may have the same width and thickness, which encourages the biasing members to generate similar spring forces when compressed and to bias the interface members in a balanced manner.

[0029] An interface member of an interface element or interface assembly may have an absorbing layer configured to absorb photon energy and generate heat when the interface member is illuminated by a light source.

[0030] The present invention also extends to a heater system comprising the thermal interface device of the above aspect and a heater device configured to heat the thermal interface member.

[0031] The heater device may be integrated with the thermal interface device.

[0032] The heater device may include a light source operable to direct radiation at the interface member. The light source may be attached to a support structure of the thermal interface device. The light source may include a light emitting diode. The light source may be configured to emit radiation in the ultraviolet and / or visible range. Such radiation is absorbed by the interface member or by a coating covering a surface of the interface member and converted to heat that is transported to the object. Compared to using radiation in the infrared range, using radiation in the visible and / or ultraviolet range may be electrically more efficient and may allow non-contact temperature sensing in the infrared range, for example with a pyrometer.

[0033] The heater arrangement may have a heater attached to or embedded in the interface member.

[0034] When the thermal interface device comprises multiple interface members, the heater device may be configured to heat each interface member individually, e.g., to heat each interface member to a different temperature and / or with a different heating power.

[0035] The invention further extends to a diagnostic device comprising an interface element, thermal interface device, or heater system of any of the above aspects.

[0036] In this aspect of the invention, biasing the interface member into engagement with the object promotes the formation of a robust thermal interface through which heat can be transferred to the object. The insulating material of the biasing member resists heat transfer through the biasing member, thus minimizing the extent to which the biasing member forms a thermal bridge that transfers heat from the interface member to any structure it contacts, such as the support structure of the thermal interface device described above. The interface element or interface assembly is thus configured to maximize the proportion of heat that is transferred to the object.

[0037] It will be appreciated that preferred and / or optional features of each aspect of the invention may be incorporated alone or in any appropriate combination in other aspects of the invention. [Brief description of the drawings]

[0038] [Figure 1] FIG. 1 is a perspective view of a heater assembly according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view of the heater assembly of FIG. [Diagram 3] FIG. 3 is a side perspective view of the heater assembly of FIG. [Figure 4] FIG. 4 illustrates the heater assembly of FIG. 1 in a diagnostic device. [Diagram 5] FIG. 5 is a diagram illustrating a flat pattern corresponding to the interface element of the heater assembly of FIG. [Figure 6] 6 is a cross-sectional view of an interface plate of the heater assembly of FIG. [Figure 7] FIG. 7 is a perspective view of a heater assembly according to another embodiment of the present invention. [Figure 8] FIG. 8 is a top view of the heater assembly of FIG. [Figure 9] FIG. 9 illustrates a flat pattern corresponding to the interface element of the heater assembly of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] In order that the invention may be readily understood, preferred, non-limiting embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings in which like features are given like reference numerals, in which:

[0040] In general terms, embodiments of the present invention provide a thermal interface device configured to create a temporary, high performance thermal interface with an object to be heated by using an interface member biased into engagement with the object, and a heater system including such a thermal interface device and a heater apparatus capable of heating the interface member, and thus the object, via the thermal interface.

[0041] In the embodiments described below, the object to be heated is a test cartridge for a diagnostic device that contains a biological sample that is heated as part of the testing process, however, it should be recognized that the thermal interface device and heater system of the present invention may be used in a wide variety of other applications for heating various types of objects or enclosures, and generally may be useful in any situation where the surface of an object needs to be heated.

[0042] In an embodiment of the invention, one or more interface members in the form of interface plates are biased into contact with a surface of an object to be heated by one or more resilient biasing members. Each interface plate and its corresponding biasing member constitute an interface assembly that is used to reliably and reproducibly create a temporary thermal interface with the object to be heated. The interface assembly may therefore be considered to function as a heating assembly.

[0043] Forcing the interface plate into contact with the object improves the thermal contact between the interface plate and the object, thereby enhancing the thermal interface without the need to permanently fasten the plate to the object with adhesives or mechanical fastening means. When used in a diagnostic device, the interface plate may replace the copper plate described above used to transport heat to the cartridge. Because the interface plate is not attached to the test cartridge, it may be part of the main device that is reused for successive test cartridges. Accordingly, the cartridge may be simplified and more disposable by omitting the copper plate.

[0044] The biasing member comprises, and may be composed predominantly of, thermal insulating material, and is configured to avoid the formation of a thermal bridge between the interface plate and the support structure to which it is attached that would otherwise impair the performance of the heater assembly by allowing heat to be transferred from the interface plate to the support structure, thereby reducing heating efficiency.

[0045] In some embodiments, a set of biasing members are evenly distributed around the edge of the interface plate, thereby balancing the biasing forces across the interface plate and holding the surface of the interface plate in firm contact with the surface of the test cartridge or other housing.

[0046] Advantageously, the interface assembly may be configured as an interface element in which one or more biasing members are integrally formed with the interface plate. For example, the interface element may have resilient legs that constitute the biasing members extending from the interface plate. In the embodiments described below, such an interface element may be formed in the manner of a rigid-flex printed circuit board (PCB), albeit with a substantially continuous conductive layer instead of the usual conductive network that defines the electrical circuit of the PCB. Advantageously, such an interface element may be produced using conventional PCB manufacturing techniques, with the legs being formed from a flexible substrate material, while the interface plate is rigid and comprising a conductive layer of copper on each side that acts as a highly efficient thermal conductor.

[0047] Alternatively, one or more biasing members can be connected to an interface plate or other interface member using any suitable connection technique to form an interface assembly, where the biasing members are separate from the interface plate.

[0048] Typically, the mass of the interface plate is small, which results in a low thermal inertia of the interface plate, which prevents thermal energy from being stored in the interface plate and thus quickly transports it to the object. The low thermal inertia therefore facilitates heating of the object or allows for rapid cooling when the heating power is removed, thereby greatly enhancing the ability to control the temperature of the object.

[0049] 1-3, there is shown a heater system or heater assembly 10 according to one embodiment of the present invention. The heater assembly 10 is configured for use in a diagnostic instrument to heat a biological sample held in a test cartridge docked to the instrument for processing, and is shown in such context in FIG.

[0050] The heater assembly 10 includes three interface elements 12 mounted in a linear arrangement on a PCB that defines a control board 14. The control board 14 serves as a support structure for the interface elements 12, and together the control board 14 and the interface elements 12 define a thermal interface device configured to form a thermal interface with a test cartridge.

[0051] The support structure also supports components of the heater device of the heater assembly 10, which is configured to heat the interface element 12. Thus, the heater assembly 10 integrates a thermal interface device with a heater device, and is configured to form a thermal interface with the test cartridge and provide heating power to the interface. However, in alternative embodiments, the thermal interface device may be separate from the heater device. Conversely, as described below, the thermal interface device may include an integral heater device.

[0052] Each interface element 12 comprises a flat, circular interface plate 16 having eight identical, equally spaced, elongated legs 18 extending radially outwardly from the interface plate 16. Each interface plate 16 has a reverse surface facing the control board 14 and an outwardly facing surface defining a mating surface which, in use, engages the surface of a test cartridge.

[0053] Each interface plate 16 of interface element 12 is configured to engage a different portion of a test cartridge housing to form a thermal interface with the test cartridge, thereby providing localized heating during the testing process. Thus, interface element 12 can be considered to function as a heating element. For example, each interface plate 16 may be aligned with a respective recess in the test cartridge upon engagement to heat sample fluid held within the recess. The test cartridge may have a recess to receive interface plate 16 to provide precise alignment when interface plate 16 engages the cartridge.

[0054] In this embodiment, each interface plate 16 has a diameter of approximately 8 mm, which may correspond roughly to the size of the cavity in which the interface plate 16 is aligned, such that each interface plate 16 transports heat uniformly throughout its corresponding cavity. In the rest state, the interface plates 16 are positioned approximately 6 mm above the control board 14.

[0055] In use, the interface plate 16 is heated and transfers heat to the portion of the test cartridge with which it is in contact. Thus, in this embodiment, the exterior surface of the interface plate 16 is constructed of a thermally conductive material, such as copper, to promote efficient and uniform heating at its interface with the test cartridge. The interface plate 16 is rigid so as to resist deformation when pressed into engagement with the test cartridge, and allows for uniform contact across its interface with the cartridge, thus promoting uniform heat transfer across the thermal interface defined by the contact area.

[0056] As best seen in Figure 1, each leg 18 is resilient and bent along its length to form a semicircular arch beneath each interface plate 16. Each leg 18 extends from the interface plate 16 at a proximal end to the control board 14 at a distal end. Thus, the interface element 12 is generally spider-like in shape. Each leg 18 is secured at its distal end to the control board 14 by brazing in this example, although any suitable attachment means may be used, such as adhesive or mechanical fastening. In this embodiment, the legs 18 are integrally formed with the interface plate 16.

[0057] The legs 18 comprise a thermal insulating material and in this embodiment are formed predominantly of such material so that when the interface plate 16 is heated, it does not create a thermal bridge between the interface plate 16 and the control board 14. The legs 18 thereby create a degree of thermal isolation between the interface plate 16 and the control board 14, thus maximizing the rate at which heat generated at the interface plate 16 is transported to the mating test cartridge. On the other hand, if a metal spring were used as the biasing member, the efficiency of the assembly would be significantly reduced.

[0058] Additionally, the legs 18 of each interface element 12 act in concert to bias each interface plate 16 away from the control board 14. Thus, when an interface plate 16 is pushed towards the control board 14, the corresponding legs 18 provide an opposing spring force that acts to return the interface plate 16 to the rest position shown in Figures 1-3. The evenly spaced legs 18 around the edge of the interface plate 16 provide a balanced biasing force that properly maintains the orientation of the interface plate 16 while pushing the entire interface plate 16 into engagement with the test cartridge.

[0059] FIG. 4 shows the heater assembly 10 in the device with the interface element 12 engaging a test cartridge 20 docked below the heater assembly 10 in the device. The device is configured such that the test cartridge 20 is closer to the control board 14 when docked than the interface plate 16 is in the rest position, as evidenced by the larger deformation of the legs 18 of the interface element 12 relative to the rest position shown in FIGS. 1-3, and the interface element 12 is compressed between the control board 14 and the cartridge 20. Specifically, in this embodiment, when the cartridge 20 is docked, there is a 4 mm gap between the test cartridge 20 and the control board 14. The interface element 12 is 6 mm above the control board 14 in the rest state, and therefore deforms 2 mm when the cartridge 20 is moved into position.

[0060] Thus, as the cartridge 20 moves into position within the device, it pushes the interface plate 16 towards the control board 14, further bending the legs 18. In response, the legs 18 create a spring force that presses the interface plate 16 against the surface of the test cartridge 20, thereby creating stronger contact between the mating surface of the interface plate 16 and the surface of the test cartridge 20, thus creating a robust thermal interface. In this embodiment, the 2 mm displacement of each interface plate 16 as the test cartridge 20 moves into position creates a spring force equivalent to 30 grams, which is proportional to the displacement of the interface plate 16.

[0061] 1-3, beneath each interface element 12, the control board 14 carries a light source in the form of a surface mounted light emitting diode (LED) 22, each LED 22 aligned with the centre of a respective interface plate 16. The LEDs 22 form part of a heater arrangement which, in use, heats the corresponding interface plate 16.

[0062] In this embodiment, each LED 22 is configured to emit radiation in the ultraviolet and / or visible range and direct said radiation to the underside of each interface plate 16. Each interface plate 16 is configured to generate heat when irradiated with radiation through a spectral conversion that converts the energy carried by the radiation photons into heat. For example, the underside of the interface plate 16 may be coated with a material that constitutes an absorbing layer to effect the required conversion; suitable materials include aluminum oxide or modified polymers such as carbon or graphene. The absorbing layer may alternatively or additionally be substantially black to provide the required absorption.

[0063] The control board 14 includes a surface track 24 and an array of contacts 26 which provide a network of electrical connections. This network includes connections between some of the contacts 26 and each of the LEDs 22 so that, in operation, the device can provide power to the LEDs 22 via the corresponding contacts 26. Further connections relate to temperature sensors embedded in each interface plate 16, as will be described in more detail below, allowing feedback loop control of the temperature of each interface plate 16 for precise heating of the test cartridge 20. Such control is performed by a main controller (not shown) for the device.

[0064] The control board 14 also has mounting holes 27 at each corner for mounting the heater assembly 10 within the device.

[0065] The heater assembly 10 is therefore configured to heat each interface plate 16 in a non-contact manner. Although it is possible to directly heat the interface plate 16, for example by using a heater attached directly to the interface plate 16, this requires the provision of a conductive path between the control board 14 and the interface plate 16 to provide power to the heater. For example, the heater may be defined by one or more copper tracks etched into the surface of the interface plate 16, and power may be provided to the heater via copper tracks extending to the legs 18 of the interface member. Such tracks would need to be relatively large due to the power consumption of the heater. Such a path would therefore form a large thermal bridge through which heat generated at the interface plate 16 would be transferred back to the control board 14, thereby reducing the heating power provided to the test cartridge 20. Thus, heating the interface plate 16 in a non-contact manner increases the heating power transferred to the test cartridge 20, thereby increasing the efficiency of the device.

[0066] Another alternative is to use LEDs that emit infrared radiation to heat the interface plate 16, thereby avoiding the need to convert radiation to heat as in the present embodiment. However, using LEDs operating in the ultraviolet and / or visible range, as in the present embodiment, can advantageously provide greater efficiency compared to infrared LEDs, and further allows for simultaneous non-contact thermal sensing, for example with a pyrometer, since heating and sensing are performed using radiation in different frequency ranges.

[0067] Because each interface plate 16 is heated using a separate LED 22, the interface plates 16 may be heated independently of each other. This allows, for example, each interface plate 16 to be heated to a different temperature, which may be useful in an apparatus performing processes requiring successive heating steps at different temperatures on a sample.

[0068] In this embodiment, each interface element 12 is formed in the manner of a rigid-flex PCB, albeit with a substantially continuous conductive layer instead of an electrical circuit, with legs 18 being integrated into interface plate 16. Legs 18 can thus be considered to represent the flexible portion of the PCB and are formed from a flexible substrate material, while interface plate 16 represents the rigid portion of the PCB and thus comprises a rigid substrate material. In general terms, interface elements 12 can be manufactured in a conventional manner by providing suitable design parameters to a PCB manufacturer. This provides a convenient means for manufacturing interface elements 12 using processes and materials that are already available.

[0069] Here, Fig. 5 shows the interface element 12 in an initial, unassembled state defining a flat pattern, corresponding to the product supplied by the PCB manufacturer. The flat pattern comprises a central disk portion, which will later become the interface plate 16, from which extend circularly arranged elongated portions, which will later become the legs 18. The legs 18 can be bent into the shape shown in Figs. 1 to 3 in order to assemble the interface element 12 to the control board 14. As is evident from Fig. 5, the profile of the interface element 12 has eight-fold rotational symmetry and eight axes of symmetry intersecting at the centre of the interface plate 16.

[0070] In this embodiment, the interface element 12 comprises a single continuous flexible substrate of the shape shown in Figure 5, with a layer of flexible substrate extending across the entire interface element 12. A variety of materials have been used for flexible substrates in PCBs, e.g. polyimide, any of which are suitable for use in embodiments of the present invention. In this embodiment, the flexible substrate has a thickness of 0.15mm, which corresponds to the thickness of the legs 18. It should be noted that the flexible substrate may be comprised of multiple stacked FPC layers, as is conventional, and may include a coverlay.

[0071] The interface plate 16 also includes a rigid substrate layer that is bonded to the flexible substrate and provides rigidity to the interface plate 16. The rigid substrate layer may be constructed of any suitable non-conductive rigid material, such as FR-4 glass-reinforced epoxy, or ceramics including alumina, aluminum nitride, and beryllium oxide.

[0072] Advantageously, while the substrate materials used in PCBs are selected based on being non-conductive from an electrical conductivity standpoint, such materials generally have low thermal conductivity and can be considered thermal insulators for the purposes of the heater assembly 10.

[0073] The substrate layers of the interface plate 16 are sandwiched between conductive layers of copper to form a laminate. FIG. 6 illustrates a cross-section of the interface plate 16, showing the layers that form the plate 16. Successively upward, the layers include an absorbent layer 28, a lower conductive layer 30, a flexible substrate layer 32, a rigid substrate layer 34, and an upper conductive layer 36. Additional substrate layers may be included between the conductive layers 30, 36. Thus, the upper and lower conductive layers 30, 36 are separated by the substrate layers 32, 34 and define the major outer surfaces of the laminate, which may include optional coatings. Optional coatings include the absorbent layer 28 and protective coatings such as thermally conductive resins that add rigidity to the structure and create a smooth surface for the interface plate 16.

[0074] While the copper layer is conventionally etched to form the necessary circuitry for the PCB, in this embodiment the conductive layers 30, 36 are left substantially intact and cover a majority of the surface of the interface plate 16. The conductive layers 30, 36 typically cover the surface of the interface plate 16 as completely as possible. For example, the conductive layers 30, 36 cover at least half of the outer surface of the interface plate 16, typically 75% or more, and preferably 80% or more. Taking into account the space taken up by any sensors and vias present, as described below, coverage up to 95% or more may be achievable. The amount of coverage of the conductive layers 30, 36 is determined by the needs of each application, taking into account the constraints of the manufacturing process.

[0075] In this embodiment, the thickness of each conductive layer 30, 36 is about 70 μm. The copper material of the conductive layers 30, 36 may have a gold coating, for example, 1U, 2U, or 3U thick, as desired.

[0076] The interface plate 16 is perforated by a plurality of through holes uniformly distributed across the interface plate 16, the inner surfaces of which are plated with copper or other thermally conductive material. The holes define thermal vias 38 which extend between the upper and lower conductive layers 30, 36 and which, in use, provide a thermal link for transporting heat between the conductive layers 30, 36.

[0077] The regions of the interface element 12 that define the legs 18 are free of a rigid substrate, and are formed almost entirely from the flexible substrate layer 32. Thus, each leg 18 is largely made up of the insulating material used in the flexible substrate layer 32. Thus, the legs 18 are made of a flexible material and have elasticity.

[0078] As shown in Figure 5, the distal end of each leg 18 is provided with a rectangular backing plate 40 made of a conductive material, for example copper. These backing plates 40 allow the legs 18 to be brazed to the control board 14. The backing plates 40 are isolated from the conductive material of the corresponding interface plate 16 and therefore do not contribute significantly to heat transport through the legs 18. Figure 5 shows a central hole 41 in each backing plate, which aids in the placement of the backing plates 40 on the control board 14 during assembly, for example by using a temporary rivet.

[0079] 5, the interface element 12 includes a trace 42 of conductive material, again typically copper, that runs through the center of the interface plate 16 and along the centers of two legs 18 that are diametrically opposed across the interface plate 16. The trace 42 connects each of the backing plates of the legs 18 and connects to a temperature sensor 44, e.g., a PT1000, attached to the interface plate 16.

[0080] Although the traces 42 do create a thermal conduction path through the legs 18, this is acceptable because the low power requirements of the sensor 44 allow the traces 42 to be small, thereby minimizing heat transport through the traces 42. In particular, the size of the traces 42 required for the sensor 44 is much smaller than the size required for a heater, and thus incorporating the sensor 44 into the interface plate 16 does not create a large thermal bridge between the plate 16 and the control board 14 as would be the case when incorporating a heater.

[0081] Thus, in use, a signal indicative of the temperature of the interface plate 16 produced by the temperature sensor 44 may be sent via trace 42 and connections provided on the control board 14 to a main controller of the apparatus. The apparatus controller then controls the operation of the corresponding LED 22 in response to the temperature signal received from the sensor 44 to control the temperature of the interface plate 16 to a target value.

[0082] Figures 7 and 8 show an alternative heater assembly 110 according to a second embodiment of the present invention in which the three interface elements 12 of the first embodiment shown in Figures 1 to 6 are replaced by a single larger interface element 112.

[0083] As in the first embodiment, the interface element 112 of Figures 7 and 8 has an interface plate 116 supported on a control substrate 114 by a set of legs 118 distributed around the periphery of the plate 116. The interface plate 116 is elongated with rounded corners and is sized to cover the entire area collectively occupied by the three interface plates 16 of the first embodiment.

[0084] Similar to the first embodiment, the legs 118 have substantially the same length and width, and therefore are bent into a similar arch when the interface element 112 is attached to the control board 114, thereby generating a similar spring force. This causes the biasing force generated by the legs 118 to be balanced around the interface plate 116.

[0085] Each leg 118 extends perpendicularly from an edge of the interface plate 116, or tangent to the edge if that edge is curved. Orienting the legs 118 in this manner helps to avoid twisting as the legs 118 bend under the interface plate 116.

[0086] As in the first embodiment, the interface element 112 shown in Figures 7 and 8 is made in the form of a rigid-flex PCB. Here, Figure 9 shows a flat pattern corresponding to the product provided by the PCB manufacturer, whose legs 118 can be bent into a predetermined shape and attached to the control board 114, as shown in Figures 7 and 8. Also, as is evident from Figure 9, the profile of the interface element 112 in Figures 7 and 8 has two-fold rotational symmetry and two perpendicular symmetry axes intersecting at the center of the interface plate 116.

[0087] Additionally, the interface plate 116 has a structure similar to that of the first embodiment shown in Figure 6. The interface plate 116 also includes an array of thermal vias 138 that connect the upper and lower conductive layers and minimize the thermal resistance between the upper and lower sides of the interface plate 116.

[0088] In the simplest embodiment, the interface plate 116 has a continuous conductive surface on each side and is heated to a generally uniform temperature, which in turn heats the corresponding portion of the mating test cartridge 20 to a single temperature. The control board 114 includes a pair of LEDs 22 that operate in parallel to heat the interface plate 116 and are spaced to promote distribution of heat generated by the interface plate 116 to promote uniform heating of the test cartridge 20. Figure 9 also shows a conductive trace 142 that extends through a pair of linearly aligned legs and connects to a temperature sensor 44 attached to the interface plate 116.

[0089] However, in the embodiment shown in Figures 7 and 8, the dashed lines indicate discontinuities formed in the conductive layer of the interface plate 116, with corresponding discontinuities formed on the opposite side of the interface plate 116 not visible in Figure 8. Each discontinuity may be formed by removing a strip of conductive material from the conductive layer, for example by etching. The discontinuities separate the interface plate 116 into two separate, isolated heating zones, each of which may be individually radiatively heated by a corresponding one of the LEDs 22. Each heating zone may also be provided with its own temperature sensor. Thus, each heating zone may be heated independently of the other by the LEDs 22 to different temperatures as desired.

[0090] Those skilled in the art will recognize that the present invention can be modified to take many forms different from those described herein without departing from the scope of the appended claims.

[0091] For example, the interface element does not have to be fabricated as a PCB, and various other manufacturing options are available to create an element having thermally insulating flexible legs that support a rigid, thermally conductive interface plate.

[0092] While a compact arrangement can be achieved by mounting the LEDs on the same support structure as the interface element, in other embodiments the LEDs may be mounted separately from the interface element. Thus, in general terms, the interface element and thermal interface device may be separate from the heating components that heat the object that creates the thermal interface with the thermal interface device. The interface device may still be considered to form part of the overall heating system in such an arrangement, in that the object is heated through the interface device. Thus, the thermal interface device may be retrofitted to an existing heating system to improve heat transport to the object to be heated.

Claims

1. 1. An interface element for a heater system configured to form a thermal interface with an object to be heated, comprising: an interface member configured to engage the object, the interface member having a thermally conductive layer supported by a rigid substrate layer and covering at least a majority of a surface area of ​​the rigid substrate layer; at least one flexible biasing member extending from the interface member and configured, in use, to bias the interface member into engagement with the object; Equipped with The biasing member comprises a thermal insulator and is configured to resist heat loss from the interface element.

2. The interface element of claim 1 , wherein the substrate layer is disposed between a pair of conductive layers.

3. The interface element of claim 2 , wherein the interface member includes a thermal link extending between the conductive layers.

4. The interface element of claim 1 , wherein the interface member comprises a rigid substrate layer and a flexible substrate layer.

5. The interface element of claim 4 , wherein the biasing member is constructed from the same material as the flexible substrate layer of the interface member.

6. The interface element of claim 5 , wherein the biasing member is continuous with the flexible substrate layer of the interface member.

7. The interface element of claim 1 , wherein the conductive layer is divided into a plurality of thermally conductive regions separated by thermally insulating regions.

8. The interface element of claim 1 , comprising a conductive path extending on the interface member along the length of the biasing member.

9. The interface element of claim 1 formed as a rigid-flex printed circuit board.

10. The interface element of claim 1 , comprising a set of biasing members disposed about the interface member.

11. The interface element of claim 10 , wherein the biasing members have substantially the same length.

12. 2. An interface element according to claim 1, having at least one axis of symmetry and / or at least one degree of rotational symmetry.

13. The interface element of claim 1 , wherein the insulating material occupies at least half the volume of the biasing member.

14. The interface element of claim 13 , wherein the biasing member is composed predominantly of insulating material.

15. The interface element of claim 1 , wherein the interface member comprises an absorbing layer configured to absorb photon energy and generate heat when the interface member is illuminated by a light source.

16. A thermal interface device for a heater system configured to form a thermal interface with an object to be heated, comprising: a support structure; A thermal interface device comprising the interface element of claim 1.

17. The thermal interface device of claim 16; a heater device configured to heat the interface member; A heater system comprising:

18. The heater system of claim 17 , wherein the heater device is integrated into the thermal interface device.

19. The heater system of claim 17 , wherein the heater device comprises a light source operable to direct radiation at the interface member.

20. 20. The heater system of claim 19, wherein the light source is attached to the support structure of the thermal interface device.

21. 20. The heater system of claim 19, wherein the light source comprises a light emitting diode.

22. 20. The heater system of claim 19, wherein the light source is configured to emit radiation in the ultraviolet and / or visible range.

23. 20. The heater system of claim 17, wherein the heater device comprises a heater attached to or embedded in the interface member.

24. The heater system of claim 17, wherein the thermal interface device comprises a plurality of interface assemblies mounted on the support structure, and the heater device is configured to heat each interface member.

25. 25. The heater system of claim 24, wherein the heater device is configured to heat each interface member individually.

26. A diagnostic device comprising the thermal interface device of claim 16, the interface element of claim 1, or the heater system of claim 17.

27. A thermal interface device for a heater system configured to form a thermal interface with an object to be heated, comprising: a support structure; an interface assembly attached to the support structure; Equipped with The interface assembly includes: an interface member configured to engage the object to form a thermal interface; a biasing member between the support structure and the interface member, which, in use, functions to bias the interface member away from the support structure and into engagement with the object; and The biasing member comprises a thermal insulator and is configured to resist heat transfer from the interface member to the support structure.

28. A thermal interface device as described in Claim 27, wherein the biasing member is integrally formed with the interface member.

29. A thermal interface device as described in claim 27, wherein the interface member is divided into multiple heating regions separated by insulating material.

30. The thermal interface device of claim 27, further comprising a temperature sensor configured to generate a signal indicative of the temperature of the interface member.

31. The temperature sensor is attached to the interface member, 31. The thermal interface device of claim 30, wherein the biasing member has a conductive path connected to the temperature sensor and extending to the support structure.

32. A thermal interface device as described in claim 27, wherein the support structure has a circuit board.

33. The interface member has a thermally conductive layer supported on a rigid substrate layer, 30. The thermal interface device of claim 27, wherein the thermally conductive layer covers at least a majority of a surface area of ​​the rigid substrate layer.

34. A thermal interface device as described in claim 33, wherein the substrate layer is positioned between a pair of conductive layers.

35. A thermal interface device as described in claim 34, wherein the interface member has a thermal link extending between the conductive layers.

36. A thermal interface device as described in claim 33, wherein the interface member has a rigid substrate layer and a flexible substrate layer.

37. A thermal interface device as described in claim 36, wherein the biasing member is made of the same material as the flexible substrate layer of the interface member.

38. A thermal interface device as described in claim 37, wherein the biasing member is continuous with the flexible substrate layer of the interface member.

39. A thermal interface device as described in claim 33, wherein the interface assembly is formed as a rigid-flex printed circuit board.

40. A thermal interface device as described in claim 27, wherein the interface assembly has at least one axis of symmetry and / or at least one degree of rotational symmetry.

41. A thermal interface device as described in claim 27, wherein the insulating material corresponds to at least half the volume of the biasing member.

42. A thermal interface device as described in claim 41, wherein the biasing member is composed largely of insulating material.

43. A thermal interface device as described in claim 27, wherein the interface member has an absorption layer configured to absorb photon energy and generate heat when the interface member is illuminated by a light source.

44. A thermal interface device as described in claim 27, comprising a plurality of interface assemblies attached to the support structure.

45. A thermal interface device as described in claim 27, wherein the interface assembly has a plurality of biasing members that function between the support structure and the interface member.

46. A thermal interface device as described in claim 45, wherein the multiple biasing members have substantially the same length.

47. A thermal interface device as described in claim 27, wherein the interface assembly is defined by an interface element as described in claim 1.

48. A heater system comprising the thermal interface device described in claim 27 and a heater device configured to heat the interface member.

49. A diagnostic device comprising a thermal interface device as described in claim 27 or a heater system as described in claim 48.

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