Long-term highly reliable electronic device

Abstract

This invention relates to an electronic device comprising at least one printed circuit board, electronic components, conductive elements, and an electrically insulating housing made of a polymer material. According to the invention, at least some of all electronic components and conductive elements are partially or completely embedded in the at least one printed circuit board. Furthermore, the electrically insulating housing made of the polymer material completely encapsulates the at least one printed circuit board and all conductive elements not yet embedded in the at least one printed circuit board without dielectric tracking. The polymer material is composed wholly or partially of polymers from the polyether ketone (PEK), polyarylether ketone (PAEK), or polyetheretherketone (PEEK) family.

Description

[0001] This invention relates to an electronic device that is highly reliable over a long period of time.

[0002] This invention has particularly interesting applications in the so-called “harsh environment” fields, such as aerospace, automotive, railway, medical devices (implantable or non-implantable), and all other fields where it is necessary to ensure that the critical functions performed by electronic devices are guaranteed over long periods of time.

[0003] Unmet needs can be characterized by certain features of the mission profile of such equipment, namely, by a sequential description of the external stresses it may endure during its product life. These external constraints are typically represented by external actions, namely the product of time and the energy exchanged between the equipment and its environment. The energy exchange is characterized by the evolution of its intensity over time and its properties, which can be mechanical, thermal, electromagnetic, chemical, or a combination of several different types of constraints, such as the simultaneous application of mechanical and thermal constraints.

[0004] Electronic devices are also characterized by internal stresses, which are influenced by factors that depend on the design and use of the electronic device (and thus on the mission profile). These internal factors can be modulated through design choices and manufacturing methods.

[0005] The reliability of electronic devices is influenced by the cumulative (optionally coupled) effects of internal and external factors, as well as design choices and manufacturing methods.

[0006] Those skilled in the art will recognize that the selection and sizing of electronic components face the same inherent challenges, and this invention will not address these issues. To reiterate, the most reliable components are selected based on the aforementioned mission profile, and the higher their inherent lifespan / reliability, the greater the margin between certain critical technology thresholds and the expected maximum stress intensity. Furthermore, the manufacturing method of these components is also crucial to their inherent reliability, and these methods need to be validated and verified through testing. In electronics, most components that meet these requirements are typically developed for automotive applications, but they are not the only ones. This is because automotive components need to operate at high maximum temperatures (greater than or equal to 125°C) while maintaining their inherent reliability.

[0007] In the context of this invention, we are particularly interested in an electronic device whose components are assembled and interconnected via conductive components on a printed circuit board (PCB) and encapsulated in a housing. The printed circuit board enables both the interconnection of electronic components via a network of conductive components and the mechanical and / or thermal assembly of electronic components. Different PCB technologies and methods are available depending on the intended environment and application. Examples include (1) the most common PCBs based on copper conductors and glass fiber reinforced epoxy (FR4) electrically and thermally insulating substrates, or (2) ultra-high voltage power electronics PCBs based on copper conductors and alumina electrically insulating substrates, which are also relatively good thermal conductors, or (3) low-voltage power electronics PCBs based on copper insulated on an aluminum substrate, providing excellent thermal conductivity, or (4) flexible PCBs based on copper insulated on a polyimide substrate and covered with an insulating protective layer, or (5) many other PCB technologies. PCBs contribute to controlling the reliability of electronic devices against internal or external mechanical and / or thermal and / or electrical and / or chemical effects.

[0008] PCB enclosures are sometimes used to enhance control over internal or external electromagnetic or chemical effects. Those skilled in the art are particularly well aware that when developing electronic devices with high long-term reliability, they must be placed in hermetically sealed enclosures to protect them from internal or external chemical and electrochemical influences.

[0009] This airtight enclosure effectively prevents contaminants or solvents from migrating to the electronic components on the PCB inside the enclosure.

[0010] Existing hermetic enclosures are made of glass, ceramic, metal, or a combination of three of these materials. The hermeticity of these enclosures is tested using a gas (typically helium) to characterize the process according to so-called "type" tests or to control each product according to so-called "series" tests. Standardized testing is based on injecting helium into the enclosure during manufacturing and detecting any leaks. When the leak is below a certain threshold, sufficient hermeticity is guaranteed to protect electronic equipment over a long period.

[0011] The purpose of airtightness is multifaceted. It aims to prevent contaminants or solvents from entering the housing, as these contaminants and / or solvents can condense and liquefy over time. The presence of liquid substances (especially oxygenated ones) accelerates redox reactions, which can be fatal to electronic devices. It should be noted that these contaminants or solvents may already be present in the housing, for example, when contained within or on the surface of a PCB substrate. Furthermore, the use of airtight housings must be combined with preventative measures such as cleaning, drying, and absorption of contaminants or solvents to eliminate electrochemical problems, regardless of the source of contamination.

[0012] Hermetic housings made of ceramics (e.g., alumina) or other crystals are known to have the advantages of electrical insulation and hermetic sealing against liquids and gases. Their disadvantages explain why they are almost nonexistent in niche applications, particularly in active implantable medical devices and aerospace (besides sealed feedthrough insulators), and these disadvantages are as follows:

[0013] - Extreme mechanical fragility,

[0014] - Difficult to form,

[0015] - High cost.

[0016] The main drawbacks of glass and ceramics (which are electrical insulators) are their extreme fragility and weight. Therefore, the hermetic housings of almost all electronic devices are made of metal, almost without exception titanium, which offers the best option in terms of cost, robustness, and operability. Because titanium is also biocompatible, it is also used as the housing for all long-term, highly reliable active implantable medical devices, such as pacemakers or neurostimulators.

[0017] Hermetically sealed titanium housings with sealed feedthroughs are known, for example, platinum / iridium alloy conductors covered with an alumina-type ceramic insulator and bonded to a titanium flange. This represents almost all high-reliability electronic devices, and in any case, all long-life (>24 months) active implantable medical devices implanted in recent years. Titanium has the advantage of ensuring complete gas and liquid sealing over a long period. For certain applications, particularly power and / or signal transmission, the only disadvantage of titanium is that it is conductive and used as an electromagnetic shield. Therefore, if energy and / or electromagnetic signals are to be transmitted, the device must be located outside the titanium housing. Typically, the antenna is housed in an epoxy head (e.g.) and connected to the electronics via a sealed feedthrough.

[0018] In all applications, using a conductive hermetically sealed enclosure presents two distinct problems. First, it has a significant weight relative to a bare PCB and introduces dead volume to prevent short-circuiting of components placed inside. Second, the enclosure cannot provide electrical protection to the environment through direct electrical isolation (from the user or other contact objects). However, the trend in critical systems is to maximize the availability of services provided and to use highly reliable electronic equipment with double electrical insulation over the long term. This is known as an “isolated” or “IT” grounded architecture. Thus, regardless of the first electrical defect, it is confined within the device and has no impact on the environment (especially ATEX-explosive atmosphere areas) or the user (particularly for implantable medical devices or isolated current sensors).

[0019] If an insulating housing is used to control internal and external chemical and electrochemical interactions, it cannot be used to control internal or external electromagnetic interactions. In this case, electrostatic or electromagnetic shielding can be used on the PCB itself, which isolates the function by maximizing reliability.

[0020] To provide electrical insulation, those skilled in the art know of the use of insulating polymer housings. These housings can perform dual functions of electrical insulation, mechanical protection, and chemical protection. They must also be biocompatible when the target application is implantable or comes into contact with skin.

[0021] Polymer materials commonly used in PCB packaging are known for their ease of use, particularly through machining and molding. These materials are primarily elastomers (e.g., silicone), thermosetting materials (e.g., epoxy resins), or thermoplastics (e.g., polyetherketone (PEK)). There has been a long history of attempting to encapsulate highly reliable electronic devices using these polymers. However, the long-term reliability of the resulting electronic devices has been systematically reduced by electrochemical failures. They can be used in electronic devices where long-term reliability is not required in harsh chemical environments. Their long-term disadvantages are as follows:

[0022] - Long-term non-airtightness due to chemical absorption (especially water) eventually leads to corrosion or electrochemical growth defects.

[0023] - Degradation related to heat, ultraviolet light, oxidation, and humidity leads to loss of original mechanical properties and / or electrical insulation and / or release of encapsulated particles, etc.

[0024] In fact, none of these materials pass the helium gas tightness test. Gases are transported through the volume of the polymer material via chemical diffusion according to a law known as Fick's Law. This is a diffusion phenomenon where the migration rate varies with a gradient of concentration levels. When the polymer is placed in a solvent (such as water), water molecules eventually become present throughout the entire volume, characterized by a mass increase on the order of a few percent to several tens of percent. It should be noted that the material is not necessarily porous in a "mechanical" sense, as permeation occurs only in gaseous form via chemical diffusion, not in liquid form. Therefore, only gaseous compounds are potentially internalized and / or released. In any case, after the second condensation step, the solvent may eventually be present in liquid form within the shell. This phenomenon is accelerated when the ambient temperature drops below the dew point (which depends on humidity levels, e.g., approximately 5000 ppm for water at 0°C and 50,000 ppm at 37°C). Only a few layers of "liquid" molecules (three or more layers, i.e., about 1 nm) are needed to create an environment favorable for electrochemical phenomena. These phenomena primarily occur at the interface between two materials, in areas susceptible to creepage.

[0025] Nathaniel Dahan's paper (titled "The application of PEEK to the packaging of implantable electronic device", Department of Medical Physics and Bioengineering, University College London, 2013) is well-known. This paper investigated eliminating or slowing diffusion through the polymer by modifying its composition or adding a conformal coating to the shell (or interior). These tests slowed the diffusion phenomenon for several months, but were insufficient to envision long-term applications lasting more than two years.

[0026] Other studies include attempts to accept solution permeation, adding desiccants and / or conformal coatings (e.g., parylene) to printed circuit boards, controlling the cleaning of contaminated surface ions necessary to trigger redox phenomena (chlorides or bromides), using gold or other precious metal electrodes (e.g., "electroless nickel-plating with gold"), and reducing voltage gradients by separating traces. Again, electrochemical phenomena are mitigated, but not sufficiently for long-term applications.

[0027] Therefore, to reduce electrochemical phenomena in electronic devices used in harsh environments (humidity, temperature, etc.), silicone or parylene coatings have traditionally been used. The advantage of silicone coatings is their low purchase and application cost (cold casting). Their disadvantage is a lack of adhesion to printed circuit boards or conductive parts or components. Silicone will contain a solvent (water), and over time, a film of the solvent (water) will form on the surface of the printed circuit board, a phenomenon known as electrostatic creep. Because silicone has converted volumetric electrical conduction to surface conduction, product lifespan is greatly improved. However, in the long run, this does not fully solve the problem.

[0028] The same observations apply to parylene. The deposition process differs in that parylene is sublimated and then deposited onto the PCB surface via adsorption. It is then condensed and polymerized to form a very thin and highly uniform layer that penetrates every corner and crevice of the electronic PCB and its components. Aside from the method being very expensive (as deposition takes a long time when the thickness is considerable), the observations are the same as with silicone. In addition to surface adhesion issues (difficulty adhering to metals, requiring delamination), parylene becomes brittle when too thick: it cracks. In the long term, the failure rate caused by electrochemical phenomena remains too high for critical applications, including implantable medical applications or in the transportation sector (aviation, automotive, rail, etc.).

[0029] Despite all these attempts, electrochemical phenomena continue to occur, reducing long-term reliability. The main electrochemical phenomena leading to defects are corrosion of conductive elements (wiring traces / electrodes), short circuits between conductive elements (traces / electrodes) due to dendrite growth, and the appearance of functionally unacceptable parasitic signals (leakage current).

[0030] The purpose of this invention is to improve the inherent reliability of electronic devices in the long term, including active implantable medical devices or biomedical diagnostic systems or current or magnetic field sensors, or other applications.

[0031] Another objective of this invention is to improve the safety of people and property in the long term, particularly by ensuring electrical and / or chemical insulation that does not release toxic substances.

[0032] This invention also aims to reduce the cost and quality of highly reliable electronic devices, which is crucial for promoting the development of such solutions in all fields, from transportation (automobiles, aviation, railways, etc.) to medicine.

[0033] At least one of these objectives is achieved by an electronic device comprising at least one printed circuit board (PCB), electronic components, conductive elements, and an electrically insulating housing made of a polymer material.

[0034] According to the present invention, all electronic components and at least some conductive elements are partially or completely embedded in the at least one printed circuit board, and the at least one printed circuit board and all conductive elements not yet partially or completely embedded in the at least one printed circuit board are completely encapsulated without creepage by an electrically insulating housing made of polymer material.

[0035] The electronic device according to the invention comprises two housings: a first housing surrounding a printed circuit board of the electronic device, and a second housing, namely an electrically insulating housing made of polymer material.

[0036] The first housing is used to embed electronic components within the printed circuit board (PCB) to eliminate any creepage and gaps. Embedding means that the same material used as the PCB substrate also serves as an insulating layer on the PCB surface, keeping the components inside and allowing direct contact between the substrate and the insulating layer. Using the same material as the substrate means using a layer without surface defects (non-adhesion, delamination, etc.). The PCB substrate is, for example, FR4 type glass fiber reinforced epoxy resin.

[0037] With the embedding according to the invention, two conductive elements (wiring traces or electrodes) between components cannot be connected by direct conductive lines in the air or along a surface. In other words, there is no electrical gap or creepage for each pair of conductors in the circuit.

[0038] When present on the surface of a printed circuit board, these electrical creepages and gaps can transform into conductive lines in the presence of contaminants and / or solvents (such as condensed water vapor). This can therefore lead to defects in the printed circuit board. Electrochemical phenomena that cause defects are more likely to occur over the long term in the presence of polarization voltage (direct current (DC) component). These phenomena originate from the surface of the printed circuit board and may become negligible in the absence of DC component. The DC component can be functional (at capacitor terminals, DC power supplies, etc.) or parasitic (self-generated by the cell effect in the presence of metal-metal junctions).

[0039] The first housing makes the electronic device robust to surface defects, but does not necessarily provide mechanical protection or double high-voltage electrical insulation (or even single insulation where it is desirable to use metallized vias to contact the potential of one of the electronic components or conductive elements), or a biocompatibility barrier in the case of medical devices. Given that the first housing significantly reduces the risk of electrical failures of the printed circuit board due to contaminants and / or solvents, the present invention provides a second housing to ensure electrical insulation and / or biocompatibility barriers and / or mechanical protection and / or chemical barriers that make the component compatible with harsh environments. However, according to the invention, an electrically insulating housing made of a polymer material is used instead of a titanium housing. Titanium has the advantage of perfect hermeticity but the disadvantage of conductivity (blocking electromagnetic signal transmission between the inside and outside). Many polymeric (optionally biocompatible) electrically insulating materials are known. They have the advantage of allowing electromagnetic signals to pass through but the disadvantage of poorer hermeticity than titanium. However, this disadvantage is largely offset by the fact that the printed circuit board has become a volumetric object capable of protecting the embedded components from any substances that might penetrate the polymer insulating material.

[0040] The electronic device according to the invention allows for the use of sealed but not hermetically tight housings according to current standards. The migration of gaseous substances via diffusion is acceptable according to Fick's law. Therefore, current helium testing becomes obsolete for this type of "non-hermetic" sealed housing.

[0041] Another advantage of replacing titanium housings with insulating housings is that the antenna radiation pattern contained in electronic devices is more isotropic because the housing does not act as an electromagnetic "shield".

[0042] In the absence of electrical creepage (meaning the continuity of materials around the embedded electronics), the embedded electronics are completely isolated from their chemical environment, thus ensuring no particle release and possible primary electrical insulation.

[0043] According to an advantageous feature of the invention, only those components and wiring traces that may generate a voltage with a DC component above their electrochemical potential during use are embedded in the printed circuit board. A threshold of 1.5V (corresponding to the electrochemical potential of gold, in particular) can be set as a criterion for determining acceptable levels of the DC component.

[0044] Alternatively, all electronic components and at least some conductive elements can be embedded in the printed circuit, regardless of their constituent materials. Preferably, conductive elements that must be external to the electronic device and accessible to its potential are not fully embedded.

[0045] By embedding, it is ensured that no pair of conductive components are exposed, i.e., there are no gaps. This means, for example, that all capacitors, diodes, transistors, voltage regulators, DC power supplies, etc., are embedded. Components without a DC component, such as induction coils through which alternating current flows, may not be fully embedded. However, for reasons of integration and space saving, and also because of the inherent electrochemical potential of various metals, they are preferably also embedded.

[0046] According to an advantageous feature of the invention, the printed circuit board can be a rigid-flexible printed circuit board, comprising a rigid portion and a flexible portion. Conductive elements, partially or fully embedded, can be arranged within the rigid portion, within the flexible portion, or between the two portions.

[0047] The "complete encapsulation" according to the invention means that all conductive elements, the at least one printed circuit board, and electronic components are located inside the housing without electrical creepage. When electrical access from outside the housing is required, one or more conductive connections can be established to electrically connect to the outside via a sealed feedthrough. In any case, the presence of electrical creepage between the inside and outside of the electrically insulating housing can be identified by placing such a device in a solvent bath (e.g., water) for a sufficient time to allow diffusion to occur, and then measuring the insulation resistance between all conductive elements and electrodes immersed in the solvent bath. The presence of electrical creepage between the inside and outside implies ionic electrical conduction. For devices with surface areas on the order of several cm², the order of "good insulation resistance" (meaning no electrical creepage) is several megaohms or even gigahertz. Such insulation resistance measurements can be performed in the same manner, but between two conductive elements exiting the housing via a sealed feedthrough. No creepage is measured between each of the two conductive elements. Finally, the control of the method proposed in this invention aims to ensure by design that there is no electrical creepage between each pair of conductive elements intended to be insulated from each other. Not all tests are feasible, whether in series tests or type tests, so controlling the manufacturing process is important.

[0048] According to one embodiment, the electronic device according to the invention may include at least one sealed feedthrough through the wall of an electrically insulating housing, the sealed feedthrough comprising:

[0049] - At least one conductive connection having at least one portion embedded in a flexible portion of a rigid-flexible printed circuit board, the flexible portion being covered by at least one electrically insulating protective top coating made of a polymer material.

[0050] - An extension of the flexible portion, which at least extends through the wall of the electrically insulating housing around the conductive connection, the extension serving as an electrically insulating flange, and there is no electrical creepage at the interface between the flange and the conductive connection.

[0051] This invention uses a portion of a flexible PCB as a component of a sealed feedthrough.

[0052] Flexible PCBs can be used to create sealed feedthroughs, provided the protective insulation layer can be used as a flange that can be assembled to a polymer insulating housing, for example, by laser welding. This assembly can be performed, for example, using a technique called "clustering," which involves simultaneously heating a portion of the electrical insulating housing and a portion of the flexible PCB to weld them together. Preferably, the heating is performed by a laser, which requires that the two parts to be welded (the electrical insulating housing and the flexible flange of the PCB) be able to absorb the energy of the laser.

[0053] The advantage of this technology lies in its provision of a relatively low-cost and highly compact sealed feedthrough. Note that after this clustering operation, the insulating protective layer of the flexible PCB becomes part of the electrically insulating housing.

[0054] Therefore, in a preferred embodiment, the sealing feedthrough can be assembled with the housing while ensuring perfect material continuity. The advantage of using the same polymer material is that a good weld joint between the housing and the flange can be ensured, for example, by ultrasonic welding, friction welding, electromagnetic heating, or, in a preferred solution, laser welding.

[0055] An electronic device according to the invention may include at least one additional printed circuit board, the two printed circuit boards being electrically connected by means of a conductive element embedded in a portion of a flexible portion.

[0056] In other words, a flexible printed circuit board (PCB) is used to extract potential from an embedded PCB, particularly by connecting it to, for example, metallized vias. The conductive element can be said to be partially embedded because the metallized via is embedded and protected by the insulator of the flexible PCB, yet remains accessible for connections outside the PCB. This allows access to the partially embedded conductive element, particularly for connecting two separate PCBs located inside an electronic device. After connecting the two PCBs together via these flexible PCBs, either the partially embedded connection is retained, or preferably, additional protection is added to the connection, so that the entire assembly forms a new, fully embedded flexible-rigid PCB. The only situation where it is desirable to keep the conductive element partially embedded is when the potential needs to be accessible outside the electrically insulating housing. In this case, a sealed feedthrough is used to ensure no electrical creepage.

[0057] According to one embodiment, the electronic device may include at least one sealed feedthrough through the wall of an electrically insulating housing, the sealed feedthrough comprising:

[0058] - At least one conductive connection having at least one portion embedded in the at least one printed circuit board.

[0059] - An electrically insulating flange made of polymer material surrounds the conductive connection, and there is no electrical creepage at the interface between the flange and the conductive connection; the electrically insulating flange made of polymer material is part of an electrically insulating shell made of polymer material.

[0060] The assembly of a sealed feedthrough electrically insulating flange made of polymer material with the remainder of an electrically insulating housing made of polymer material is described below. Preferably, the polymer material of the electrically insulating flange has the same chemical properties as the polymer material of the remainder of the electrically insulating housing.

[0061] To ensure no electrical creepage between the conductive connection of the hermetically sealed feedthrough and the electrically insulating flange made of polymer material, conventional techniques are used, such as high-voltage polymer injection or compression, or chemical adhesion between compatible materials. When the device is subjected to significant mechanical forces, there are two strategies regarding the flange material. The first involves using a rigid material that prevents any deformation below a certain force. This is the first solution used with “conventional” high-reliability hermetically sealed feedthroughs, where the insulator is glass or ceramic. The second solution involves using a material with some flexibility, capable of absorbing mechanical forces without preventing mechanical deformation. This second solution is often used for relatively short-term reliability applications. They are hermetically sealed but not hermetically sealed. In the long term, the problem remains electrical creepage due to mechanical forces. Preferably, we will see the use of thermoplastic materials that both absorb mechanical forces and ensure deformation without electrical creepage.

[0062] Ideally, the flange of the at least one sealing feedthrough is made of the same material as the housing to facilitate its assembly, for example, by laser welding. Thus, the sealing feedthrough forms part of the sealing housing.

[0063] One or more sealed feedthroughs can be configured. The sealed feedthroughs can be connected to the electrodes directly or via insulated cables.

[0064] Preferably, the sealed feedthrough is manufactured separately. The sealed feedthrough may consist of at least one conductive connection and an insulating polymer flange. The sealed feedthrough can be manufactured using a process that guarantees a very high level of reliability without electrical creepage. In a preferred embodiment, this manufacturing is achieved by overmolding or thermoforming the conductor with an insulating material. The overmolding conditions are defined to guarantee long-term reliability for a given mission profile (temperature, pressure, mechanical stress, etc.). In a preferred embodiment, the material used for the flange is the same as the material used for the housing. In another preferred embodiment, the conductive connection may be flexible, or consist of extremely thin wiring traces, or consist of multi-strand stranded conductors.

[0065] For example, compared to conventional sealed feedthroughs that use ceramic as an insulator and a metal flange, the flange in this paper serves as both a sealing and electrical insulating element and a material continuity element. The sealed feedthrough provides the additional function of absorbing external mechanical forces. Eliminating the ceramic portion reduces manufacturing costs and improves the long-term robustness of the equipment.

[0066] Advantageously, and in addition to the above, at least a second conductive element may be provided in the same sealed feedthrough or in another sealed feedthrough. The two conductors may form a dipole capable of withstanding DC voltage and conducting DC current.

[0067] According to the invention, at least one conductive element is contained within a multi-strand stranded conductor covered by at least one electrically insulating protective sheath made of polymer material. This solution can be used for sealing feedthroughs, in which case the protective sheath is also part of the flange and the electrically insulating housing, or for sealing feedthroughs extending outside an electronic device. Then, according to the method described later, the electrically insulating protective sheath of the cable made of polymer material is assembled to the electrically insulating flange of the sealing feedthrough made of polymer material without introducing electrical creepage.

[0068] According to the invention, at least one of the electronic components of the device is a self-inductor coil designed to receive or transmit information and / or energy by magnetic coupling with the device located outside an electrically insulating housing made of polymer material; the self-inductor coil is embedded in the at least one printed circuit board.

[0069] According to the present invention, an electrically insulating housing made of polymer material includes at least one hole that completely passes through the electrically insulating housing made of polymer material; said hole is manufactured such that it does not introduce any electrical creepage. This hole is made possible by the housing assembly technique described below. Adding through holes to a sealed housing is a feature of interest for a variety of applications. This feature is more difficult to achieve with titanium housings, which is why it is not found in currently available products. For example, active implantable medical devices can be easily secured to a patient's human tissue using sutures through these holes. This is a considerable advantage for holding the device in place. Such holes in the electrically insulating housing can also be used to allow high-voltage conductors to pass through the device while ensuring their insulation. This allows, for example, the creation of current-isolated current sensors. Such holes can also be used to allow chemical or biological substances to pass through electronic devices, for example, for in vivo or in vitro biomedical diagnostics.

[0070] The hole is manufactured to prevent any electrical creepage between the inside and outside of the housing. This is achieved by ensuring material continuity or seamless welding. Creepage-free chemical bonding can also be achieved. The ability to creepage can be characterized by the ability of ionic (charged) matter to follow a path under the influence of a continuous electric field. Avoiding any electrical creepage means ensuring electrical insulation even in the presence of contaminants and / or solvents.

[0071] According to the present invention, the at least one printed circuit board includes at least two substantially identical self-inductance coils embedded in the at least one printed circuit board. They may also be embedded separately in two rigid printed circuit boards interconnected by a flexible PCB as described above. The advantages of these two substantially identical self-inductance coils can be understood in the implementation of certain power transfer systems or magnetic sensors. Combined with the presence of a through-hole through which one of the at least two self-inductance coils can pass, the biomedical NeelEffect® diagnostic system, as described, for example, in US-20180188206-A1 or US-20240036125-A1, can be realized.

[0072] "Substantially identical" means that the inductance difference between these at least two self-inductors is less than 5%, 2%, or even 1%.

[0073] Current measurement, especially differential measurement, can be performed by passing the object under test through a hole or placing it near one of the coils. Therefore, conventional Rogowski coil-type techniques (air transformers) can be used to measure the alternating current or transient components of the current. However, it is also possible to measure the direct current (DC) component of the current.

[0074] According to the present invention, the at least one printed circuit board comprises a superparamagnetic composite material; the superparamagnetic composite material is fully embedded in the at least one printed circuit board. This type of material is particularly useful for the production of DC magnetic field sensors or DC current sensors, based on the Nell effect® technology described in US-20180080961-A1 or US-20200011900-A1. In fact, the present invention enables the production of this type of sensor with significant advantages in terms of compactness and high reliability.

[0075] According to the invention, at least one of the electronic components is a planar self-inductor fully embedded in a printed circuit board and generated by the wiring traces of the printed circuit board. The advantages of fabricating a planar self-inductor in a PCB are well known to those skilled in the art: it provides excellent reproducibility and repeatability, as well as extreme compactness. Such advantages are particularly useful, for example, in controlling the resonant frequency specific to various applications when the self-inductor is coupled to a resonant capacitor, or in realizing a pair of substantially identical self-inductors.

[0076] According to the invention, the at least one PCB itself can be made of the same material as the electrically insulating housing. Initially, the reuse of conventional PCB technology (e.g., epoxy matrix) and the addition of encapsulation within an epoxy housing was considered. However, the invention aims to achieve all functionality using the best possible material, and this advantage can be achieved by preferably using a PEK housing as described below. The insulating portion of the printed circuit board can then be made wholly or partially of PEK, effectively creating an electronic device that integrates the printed circuit board and the electrically insulating housing.

[0077] The solution according to the invention enables the "smartification" of any purely mechanical implantable device by integrating remote communication and radio frequency power supply devices therein. Any implantable device is, for example, a knee joint, femur, spinal prosthesis, or any other type of prosthesis. There is no electrical contact between the embedded electronics and the exterior of the housing. The solution also enables the "smartification" of purely mechanical structures (e.g., wings or car bumpers) by directly integrating remotely powered sensors and electronics into the structure.

[0078] According to an advantageous feature of the invention, the polymer material may be composed wholly or partially of polymers from the polyether ketone (PEK) family, the polyarylether ketone (PAEK) family, or the polyether ether ketone (PEEK) family.

[0079] The use of PEK polymers enables the achievement of all functionalities, such as electrical insulation, mechanical retention and absorption of mechanical forces, sealing, porous or non-porous molding, and biocompatibility. PEK polymers also demonstrate proven superior reliability compared to other solutions in terms of high melting temperature, thermoplastic behavior, ductility, hardness, and elasticity within a certain deformation range. In particular, PEK allows for minimal material thickness, which improves integration without compromising other properties required for insulation. The polymer can be polyetherketone, polyaryletherketone (PAEK), or polyetheretherketone (PEEK).

[0080] According to existing technology, for a given and repeatable geometry and design, the characteristic time constant of the probability of defect occurrence (“failure time”) follows Arrhenius's law. This empirical law includes parameters (scaling factor or exponential factor of activation energy) that depend on the design selection. The rate of defect occurrence varies exponentially with temperature. Therefore, the aging process can be accelerated by increasing the temperature during the qualification step. The dual advantages of using high-temperature materials such as PEK polymers are thus readily apparent. They improve reliability due to less susceptibility to aging effects and allow accelerated aging tests to be performed during development and qualification if the design is repeatable.

[0081] Utilizing the previously described sealing feedthrough flanges made of polymer, each flange of the sealing feedthrough can be assembled to the electrically insulating housing, for example, by laser welding, eliminating any electrical creepage. This can be achieved by using a polymer material capable of absorbing laser energy (natural or with the addition of specific fillers), or, as described below, by using a combination of two substantially identical polymer materials, only one of which is capable of absorbing laser energy. The sealing feedthrough flanges can then be welded to the electrically insulating housing either by clustering (simultaneously heating two portions in a given volume) or by transmission welding (heating the surfaces at the interface).

[0082] The electrically insulating protective top coating made of polymer, as described above, can also ensure a perfect bond between the flexible printed circuit board and the electrically insulating housing, for example, through laser welding between the electrically insulating protective top coating and the insulating housing. It is understood that such a flexible printed circuit board can then be used as a sealed feedthrough. Again, this method can be based on clustering technology or transmission welding technology based on the mechanical configuration of the device.

[0083] Using the previously described polymer-made electrical insulating protective sleeve, a perfect bond can be ensured between the electrical insulating protective sleeve and the electrical insulating housing or sealing feedthrough flange, for example, through laser welding. Again, this method can be based on clustering technology or transmission welding technology based on the mechanical configuration of the equipment.

[0084] Utilizing the insulation of at least a portion of a printed circuit board made of polymer as described above, the printed circuit board itself is adapted to form an electrically insulating housing made of polymer material. This technology is ultra-compact because there is only a single object, namely the PCB and the housing. The top coating of such a housing can be produced by laser welding polymer sheets of polyetherketone (PEK), polyaryletherketone (PAEK), or the polyetheretherketone (PEEK) family using a technique known as clustering.

[0085] The aforementioned components can be combined in a single device and executed sequentially, for example, starting with a rigid PCB, then a flexible PCB, then a sealed feedthrough, then an electrically insulating housing, and finally a cable sheath. The result is an extremely versatile technology capable of producing a wide variety of highly reliable electronic devices over long periods.

[0086] According to the present invention, an electrically insulating housing made of polymer material may include at least one epoxy resin portion. The advantage of this material is its ease of implementation. The resin can be used to bond two portions of the electrically insulating housing made of polymer, or to encapsulate conductive elements to form an electrochemical barrier. In this case, it is preferable not to place conductive elements that would generate electrical creepage on the same surface (e.g., a PCB). This solution has the advantage of simple implementation, but it is not optimal because epoxy resin is a thermosetting polymer material and cannot absorb mechanical forces very effectively over a long period.

[0087] According to the present invention, the polymer material may include silicone or ultra-high molecular weight polyethylene (UHMWPE). The latter has a lower melting temperature than PEK (<136°C) and can be below the highest acceptable temperature for embedded electronics. On the other hand, it is noted that UHMWPE is less reliable than PEK over very long periods.

[0088] According to the present invention, the electrically insulating housing may comprise at least two distinct portions, the polymer materials of which have substantially the same chemical composition, but one portion is filled with a substance that makes its laser energy absorption rate at least 10 times, or even 100 times, or even 1000 times that of the other portion. "Substantially the same composition" as used herein means the same chemical composition except that a filler is added to one of the two portions.

[0089] The mass filling rate of the absorbent material can be less than or equal to 1%, or even less than 0.1%, or even less than 100 ppm.

[0090] The material's filler ratio must be lower than the filler ratio at which electroosmosis occurs; exceeding this ratio will cause the material to become resistive, or even conductive rather than electrically insulating. Its plastic mechanical properties will also be altered.

[0091] The goal of using polymer materials from the polyetherketone (PEK) family, or more precisely, the polyaryletherketone (PAEK) family, which have low carbon content, is:

[0092] - Retains excellent chemical, mechanical, and thermal properties.

[0093] - Retains "insulating" electrical properties, and

[0094] - Significantly increases the absorption of electromagnetic waves in the infrared or near-infrared bands, which is beneficial for welding operations.

[0095] Preferably, the absorbent material is pure amorphous carbon in the form of so-called "carbon black". Coloring pigments, as are well known to those skilled in the art, can also be used. However, carbon black allows for increased laser absorption with minimal mass filler, meaning less reduction in the excellent inherent properties of PEK.

[0096] Electrically insulating housings made of polymers can be produced through overmolding. In fact, overmolding can be used to ensure material continuity in the polymer-based electrically insulating housing to prevent electrical creepage, taking care not to exceed the maximum temperature that the embedded electronics can withstand (approximately 175°C for several minutes). Electrically insulating housings made of polymers can also be produced by 3D printing.

[0097] However, preferably, the electrically insulating housing is manufactured by welding several components (e.g., two parts or two half-shells) together. Each part can be produced by pressure injection using a mold or by cryogenic compression without material discontinuities. One of the two parts can be laser-transparent, i.e., it does not absorb the energy of the laser beam. This is, for example, for wavelengths on the order of 1µm and in any case less than 2µm, for polymers of the so-called "natural" polyetherketone (PEK), polyaryletherketone (PAEK), or polyetheretherketone (PEEK) family. Therefore, the laser beam can pass through this part of the housing without heating it. Obviously, preferably, the other part of the housing is designed to absorb the power of the laser beam. This is, for example, for wavelengths of about 1µm, for polymers of the so-called "filled" polyetherketone (PEK), polyaryletherketone (PAEK), or polyetheretherketone (PEEK) family. Therefore, perfect laser welding can be achieved at the interface between the two parts (one so-called "natural" part and the other so-called "filled" part).

[0098] One of the major advantages of this technology is that it allows laser welding to be performed in hard-to-reach locations, such as at the interface between two overlapping portions used to seal feedthroughs at the edge of a device, or at the edge of an inner bore in a housing.

[0099] Another laser welding technique involves using two essentially identical and absorptive parts and simultaneously heating them within their volume under the action of a laser. This so-called "clustering" technique produces excellent weld joints within the volume but near the outer surface of the assembled parts.

[0100] In all cases, preferably, the lower part will therefore be a filler portion, and a sealed feedthrough flange made of polymer and / or an electrically insulating protective top coating and / or an insulating sheath of multi-strand stranded conductors made of filler polymer can preferably be designed for assembly by laser welding.

[0101] Preferably, the insulating shell can be produced by simultaneously injecting or compressing two materials: a "natural" material that is transparent to laser and a "filler" material that absorbs laser, to form a localized solder area using one of the two techniques. For example, it may be advantageous to place the transparent area outside a sealed feedthrough flange, or outside a flexible PCB protection element, or outside a cable sheath (which is itself absorbent).

[0102] Typically, components made of polymer materials are assembled, either wholly or partially, by laser welding.

[0103] As an example, the device could be biocompatible for use as an active implantable medical device. This means, for instance, that the electrically insulating housing made of polymer materials, as well as any hermetically sealed conductive elements, are biocompatible.

[0104] Therefore, the application of this device is intended for transdermal energy transmission, in which an active implantable medical device is able to capture electromagnetic energy provided by an external source without any puncture connection to the skin.

[0105] The device according to the invention is also intended for non-contact measurement of the mass of superparamagnetic materials as part of rapid in vivo or in vitro biomedical diagnostics.

[0106] The device according to the invention is also intended for use in DC magnetic field or DC current measurement, wherein non-contact measurement of at least the static component of the magnetic field is performed.

[0107] Other benefits and features of the invention will become apparent upon examination of the detailed description and drawings of the non-limiting embodiments, wherein:

[0108] [ Figure 1 ] Figure 1 This is a schematic cross-sectional view of an electronic device according to the present invention, which includes electronic components and conductive elements fully embedded in a printed circuit board, and an electrically insulating housing consisting of two assembled parts, one of which is natural and transparent to lasers, and the other is filled and absorbs laser energy.

[0109] [ Figure 2 ] Figure 2 This is a schematic 3D diagram of electrical creepage and clearances on a conventional printed circuit board.

[0110] [ Figure 3 ] Figure 3 This is a schematic cross-sectional view illustrating a conductive element and a sealed feedthrough partially embedded in a printed circuit board according to the invention. The insulating flange of the sealed feedthrough is externally soldered to an electrically insulating housing without electrical creepage.

[0111] [ Figure 4 ] Figure 4 This is a schematic cross-sectional view of a flexible PCB used as a sealed feedthrough according to the present invention, and

[0112] [ Figure 5 ] Figure 5 This is a schematic cross-sectional view of a device with holes according to the present invention.

[0113] The embodiments disclosed below are by no means limiting; in particular, variations of the invention may be achieved by including only the selection of features disclosed below that are separated from other features, if such set of features is sufficient to provide a technical advantage or to distinguish the invention from the prior art. This set of features includes at least one preferably functional feature that has no structural details, or only a portion thereof, if such portion alone is sufficient to provide a technical advantage or to distinguish the invention from the prior art.

[0114] In particular, all disclosed variations and all disclosed embodiments are intended to be combined with each other in any combination that does not present any technical obstacles.

[0115] In the accompanying drawings, the same reference numerals are used for features common to multiple drawings.

[0116] Although the invention is not limited thereto, we will now describe electronic devices equipped with housings based on insulating materials of the polyether ketone (PEK) family or more precisely, the polyarylether ketone (PAEK) family.

[0117] Figure 1 An overall view of an electronic device 1 according to the present invention is shown. The printed circuit board 2 is not only a substrate (on which electronic components are mounted), but also a bulk material in which electronic components 3 and conductive elements 4 are embedded.

[0118] Printed circuit board 2 is, for example, based on FR4 type glass fiber reinforced epoxy resin, but it can also be made of PAEK. This same material serves both as the mechanical substrate of the printed circuit board and as an insulating layer on the surface of the printed circuit board, keeping electronic components and conductive elements inside and in direct contact between the substrate and the insulating layer. By using the same material for both the insulation and the substrate, the lamination process ensures that the bonding between the layers is free of surface defects, thus preventing electrical creepage. Lamination is used for assembly within the volume. It can be completed on the surface using laser bonding clustering technology.

[0119] exist Figure 1 In the example shown, all electronic components and all conductive elements are embedded within the volume of printed circuit board 2. However, it is possible to embed only a portion of these conductive elements.

[0120] The technique of embedding components in printed circuit boards is known to those skilled in the art and was originally developed to increase the integration of electronic devices, but its function is utilized herein because it eliminates, for example, Figure 2 This refers to any creepage and any gaps defined in the standard. No electrical creepage is achieved when there is material continuity around the electrical conductor. When there is an interface between two different materials, chemical adhesion must be ensured to avoid this electrical creepage, including after solvent absorption. This adhesion is even better when the two materials have essentially the same chemical properties. When electronic devices are subjected to mechanical stress (especially bending stress), the mechanical behavior of the materials must also be considered to avoid delamination. There are two complementary solutions: one is to mechanically reinforce the substrate, and the other is to make the substrate flexible. The former is used in rigid PCBs with thermosetting substrates, and the latter is used in flexible PCBs with thermoplastic substrates; both are used in flexible-rigid printed circuit boards or flexible-rigid PCBs. Minimal mechanical rigidity can be maintained on electronic components to avoid damaging the solder joints of electronic components on conductive elements.

[0121] Figure 1 A housing 5 is also shown, which completely surrounds the printed circuit board 2 without any material discontinuities. A space 52 (e.g., filled with air) may exist between the housing 5 and the printed circuit board 2, particularly when the printed circuit board is held by studs. This space may be completely or partially absent when the housing is obtained, for example, by overmolding. The housing 5 is made of a biocompatible insulating material, such as polyetherketone (PEK) or more precisely polyaryletherketone (PAEK), which is a thermoplastic polymer that can be machined, extruded, or injected by those skilled in the art. The assembly, including the printed circuit board, electronic components, and conductive elements, can be overmolded with PEK at temperatures above the glass transition temperature and for a period of time to maintain the integrity of the electronics on the printed circuit board.

[0122] The function of the housing 5 is to provide secondary insulation and / or biocompatibility or chemical resistance that the printed circuit board 2 may not necessarily have, to act as a barrier against any contaminants, to ensure electrical insulation between the printed circuit board and the user or equipment, and to allow any transfer of electromagnetic energy (radio frequency communication and / or energy transfer) between the inside and outside of the housing.

[0123] According to the present invention, the electrically insulating shell comprises at least two different parts 5A and 5B, whose polymer materials have substantially the same chemical composition, but one part is filled with a substance that makes its laser energy absorption rate at least 10 times, or even 100 times, or even 1000 times that of the other part.

[0124] According to the present invention, this result can be achieved without changing other inherent properties of the polymer material when the mass filling rate of the absorbent material is less than or equal to 1%, or even less than 0.1%, or even less than 100 ppm.

[0125] According to the present invention, the absorbent material is carbon black, which has a very high absorption capacity. It also has the advantage of being the simplest absorbent element already present in the composition of most polymers, especially PAEK. Carbon-filled PAEK is known for its biocompatibility. However, care must be taken not to overfill the composite material, as this may degrade its electrical, mechanical, or chemical properties. Carbon black enables this goal to be precisely achieved with minimal filling rate.

[0126] The design of an electrically insulating shell consisting of two parts 5A and 5B (e.g., a white part (so-called natural and laser-transparent) and a black part (filled, absorbing laser)) with substantially similar chemical, electrical, and mechanical properties but substantially different laser energy absorption rates advantageously enables the production of robust shells free from electrical creepage. This technique is known to those skilled in the art; it involves depositing the absorptive part 5B inside the transparent part 5A, and then irradiating the interface with a laser beam. The laser beam passes through the transparent part without heating and is absorbed at the interface 5C between the two parts 5A and 5B. The beam is typically low-power (<1kW) and continuous, allowing energy to diffuse sufficiently at the interface, producing a weld seam completely free of electrical creepage.

[0127] Figure 2 A conventional printed circuit board is shown, consisting of an insulating planar substrate 6 on which conductive elements 7 are mounted. Contaminants and / or condensed water vapor can deposit on the surface of the insulating planar substrate 6, creating unwanted conductor lines between the conductive elements 7, a phenomenon known as electrical creepage. To reduce this phenomenon, barriers 8 and spacers 9 can be created on the substrate to extend the length of electrical creepage 10 and gaps 11. A gap represents the shortest distance between two conductors in air. Electrical creepage represents the shortest distance between two conductors along a surface.

[0128] In the presence of contaminants and / or solvents (e.g., water) and polarization voltage, barriers 8 and spacers 9 are insufficient to prevent defects from occurring long-term. The solution of this invention is to embed all components (active and passive) and conductive elements inside the printed circuit board. The same material is used around the conductive components and elements. Therefore, electrical creepage and gaps are eliminated. For each pair of conductors in the circuit, there are no electrical gaps or creepages. Adding a simple conformal surface coating eliminates gaps, but cannot eliminate electrical creepages caused by poor long-term adhesion at the interface with the insulating planar substrate 6. Using the same material as the insulating planar substrate 6 as a coating eliminates electrical gaps and creepages. It is in this sense that we talk about... Figure 1 The printed circuit board 2 shown exhibits material continuity, such as FR4. In this case, the material continuity of the printed circuit board 2 protects the conductive elements 4 and the embedded electronic components 3 from all electrochemical phenomena. However, since this material of the printed circuit board 2 is generally not biocompatible and / or requires double electrical insulation, the continuity of the printed circuit board 2 alone is insufficient to guarantee long-term reliability. Figure 1 Material continuity is also required in the casing 5, but a different material is used, such as PAEK, which is electrically insulating, chemically resistant, and biocompatible. In this way, the material continuity of casing 5 protects the user from any electrical hazards and / or particulate release. It should be noted that when the PEK material is immersed in a solvent (such as water) for an extended period, it will load gaseous water molecules through a process called Fick diffusion. The material is sealed but not airtight. However, there is no electrical creepage, ensuring that the insulation properties of the water-filled PEK are maintained, thus ensuring that electrochemical phenomena do not occur.

[0129] When it is desired to reach potentials located inside a PCB (e.g., in electronic components), it is necessary to be able to bring out conductive elements without introducing electrical creepage. Sealed feedthroughs can be used for this purpose.

[0130] Figure 3 The sealed feedthrough 12 is created during the manufacture of the printed circuit board 2 (it may also be later assembled onto a flexible portion of the printed circuit board). In this method, the sealed feedthrough becomes a component partially embedded in the printed circuit board 2, as its conductive elements remain externally accessible. In this case, the sealed feedthrough 12 is typically shaped so that it can be soldered to the desired potential, for example using an SMD (Surface Mount Device) soldering process. The conductive connection 13 extends from the trace 4 through the printed circuit board 2 and the flange 14 to the end outside the housing 51. All conductive components remain completely encapsulated within the housing. Only the conductive connection extends through the housing.

[0131] The flange 14 is partially contained within the printed circuit board 2 and does not need to simultaneously include both an insulating region and an attachment region, as the PEK polymer material serves both purposes. This is achieved, for example, by laser welding between the insulating flange and the sealing housing. The flange then forms part of the insulating housing. It is understood that the choice of material and manufacturing process are among the keys to ensuring successful operation in eliminating electrical creepage. This is why selecting material 14 from PEK, and more particularly PAEK, is important and forms part of this invention.

[0132] exist Figure 3 In the middle, the shell 51 is made of two essentially the same materials, but one (51B) is filled to absorb laser energy, while the other (51A) is as follows: Figure 1 What is shown is transparent. It can be viewed from... Figure 3 Laser beams are applied from right to left and from the outside to the inside, and assembly is performed by transmission laser welding.

[0133] To ensure material continuity within housing 51, conductive connection 13 is surrounded by flange 14, the material of which is the same as that of housing 51B (filled). For example, PEK, more precisely PAEK. The biocompatible sealed feedthrough 12 can be assembled to housing 51A using methods known to those skilled in the art, ensuring material continuity within the housing. Assembly is preferably performed via laser welding using a transmission welding technique between flange 14 and housing 51A.

[0134] Advantageously, the material of flange 14 can be filled with carbon black as previously described, noting the use of natural (unfilled) PEK, more precisely PAEK, for the housing 51A. Therefore, welding will be performed using transmission laser welding technology around the entire periphery of the flange (e.g., circularly) and at the interface with housing 51A, making electrical creepage impossible. Figure 3 In this process, a laser can be applied from the right (outside) to the left (towards the interior of the housing), targeting the sidewall 14A of the flange 14, which is obtained by embedding the flange into the sidewall thickness of the housing. A portion of the flange extends at least to the outer end of the housing. Using the same welding technique, the two parts 51A and 51B of the insulating housing, as well as the sealing feedthrough 12, can be assembled without electrical creepage. In practice, we weld the sealing feedthrough first, and then weld the housing.

[0135] If at least a second conductor is required (e.g. for connecting electronic equipment to a bipolar cable), then either the second conductor is placed in the same flange 14 as the first conductor 13, or preferably the second sealing feed is placed near the sealing feed 12 to facilitate cable assembly.

[0136] It may be necessary to bring conductive components out of the PCB without removing them from the sealed housing. For example, this could be used to connect two PCBs together. Preferably, metallized vias are used to maximize the potential on at least one side of the PCB. Therefore, it is meaningful to be able to both “close” the metallized vias, which may be affected by electrochemical phenomena, and to offset the conductive components without introducing creepage. For this purpose, a flexible PCB is preferably used, which is placed on at least one side of the PCB. The via on the other side of the PCB is then blinded by adding a protective top coating to its entire surface. This layer can be assembled by conventional lamination or by laser engraving. The flexible PCB is typically covered with an electrically insulating protective top coating. This flexible PCB can then be used to interconnect another PCB also located inside the housing. Preferably, the two flexible PCBs are soldered together using another interface PCB. This creates electrical creepage at the solder joint. For example, the solder joint can be molded with an insulator such as thermosetting epoxy. Preferably, the solder joint can be encapsulated inside a small PEK housing, which is soldered to the flexible PCB, for example, by laser engraving. A flexible-rigid PCB consisting of several flexible and several rigid parts was obtained, with no electrical creepage at all.

[0137] Sealed feedthroughs can be embedded in flexible PCBs and then assembled in the same manner as described above. This technology facilitates the production of embedded PCBs because introducing the sealed feedthrough gap area during PCB manufacturing requires additional operations. Adding sealed feedthroughs to the flexible portion of a flexible-rigid PCB, however, can be done retroactively.

[0138] Figure 4 An example embodiment is shown, in which the printed circuit board or PCB is a rigid-flex printed circuit board. It consists of a rigid printed circuit board 2A associated with a flexible printed circuit board 2B. Electronic components and conductive elements may be arranged in the rigid printed circuit board, in the flexible printed circuit board, or between both.

[0139] Each side of the flexible printed circuit board 2B is covered with an electrically insulating protective top coating 15. Preferably, it is made of PEK or PAEK filled to absorb laser energy.

[0140] exist Figure 4 In this configuration, the sealed feedthrough consists of a conductive connection 16 and an extension of the flexible printed circuit 2B, which is the portion of the flexible printed circuit 2B (and its top coating) that is not directly attached to the rigid printed circuit board 2A and extends through the housing 51. The housing 51 also includes an outward extension 51C that frames the extension of the flexible printed circuit board 2B.

[0141] The electrically insulating protective top coating 15 is made of the same material as the extension 51C on either side, such as filled PAEK, so that it can be soldered to the housing using laser engraving technology. For this purpose, the areas 17 and 18 of the extension 51C that are in direct contact with the protective top coating 15 of the flexible printed circuit board 2B are filled with carbon black.

[0142] Figure 5 A device according to the invention, comprising holes in a housing, is shown. The housing is identical in nature to housing 5, made of two materials 22B and 22A (filled and unfilled), but has holes 19 and 20. These holes can be used for attachment or for the passage of external electrical, mechanical, chemical, or biological elements.

[0143] At least two substantially identical self-inductor coils (not shown) are embedded in a printed circuit board 23, which may be a rigid or rigid-flexible printed circuit board. The coils serve as magnetic sensors. They can then be used to measure the amount of superparamagnetic material for biomedical diagnostic applications by passing a sample through an aperture, the amount of magnetic material in the sample representing the amount of analyte that must be measured. Advantageously, the aperture passes through at least one of the two coils to contain the sample. Differential measurements rely on the fact that the other coil does not contain superparamagnetic material, which improves the signal-to-noise ratio of the measurement.

[0144] Figure 5 The device may include all the features described in the other figures. For example, the hole diameter is 1 mm and extends throughout the entire height of the housing. Holes 19 and 20 pass through housings 22A, 22B and printed circuit board 23 (same type as printed circuit board 2 or 2A-2B, but with through holes) without damaging electronic components 24.

[0145] Studs 25 and 26 form part of the housing and are formed inside the housing, between two opposing walls. These studs are drilled in the middle, creating a hole that passes through the entire housing. The housing is then assembled from two PAEK half-shells 22A and 22B. To ensure no creepage, for example, by using a method from the outside in (in...) Figure 5 In this case, a laser is applied to the top of the housing, and two PAEK half-shells are welded together using transmission welding technology, thus ensuring material continuity. Therefore, preferably, the lower part of the housing is made of filled PAEK, while the upper part is natural (unfilled). Welding is thus performed at the interface between the two parts of the housing. It should be noted that such a sealing geometry is impossible to achieve with a titanium housing because transmission welding is not possible, which explains why current titanium housings do not have attachment systems or holes for any other applications. The object of this invention is to eliminate this problem, thereby developing long-term, high-reliability electronic devices that require through-holes.

[0146] Other applications that could benefit from this invention include the possibility of altering the properties of the medical device housing to enable it to transmit energy and / or information (implantable pacemakers and defibrillators, mechanical cardiac assist devices such as LVADs (left ventricular assist devices), whole hearts, implantable cardiac monitors (implantable circulatory recorders), intramedullary limb extension systems, implantable pumps, artificial kidneys, cochlear implants, neurostimulators, implantable human-machine interfaces, etc.), and the way in which purely mechanical prostheses are made intelligent by adding medical device functionality.

[0147] Of course, the present invention is not limited to the examples described above. Many modifications can be made to these examples without departing from the scope of the invention as disclosed.

Claims

1. An electronic device comprising at least one printed circuit board, electronic components, conductive elements, and an electrically insulating housing made of a polymer material. Its features are: - At least some of all electronic components and conductive elements are partially or completely embedded in the at least one printed circuit board, and - An electrically insulating housing made of polymer material completely encapsulates the at least one printed circuit board and all conductive elements not yet partially or completely embedded in the at least one printed circuit board without electrical creepage; the polymer material is composed wholly or partially of polymers of the polyether ketone (PEK), polyarylether ketone (PAEK), or polyether ether ketone (PEEK) family.

2. The device according to claim 1, characterized in that, The printed circuit board is a rigid-flexible printed circuit that includes rigid and flexible portions.

3. The device according to claim 2, characterized in that, It includes at least one sealed feedthrough through the wall of the electrically insulating housing, the sealed feedthrough comprising: - At least one conductive connection having at least one portion embedded in a flexible portion of the rigid-flexible printed circuit board, the flexible portion being covered by at least one electrically insulating protective top coating made of a polymer material. - An extension of the flexible portion, which extends at least through the wall of the electrically insulating housing and surrounds the conductive connection, serves as an electrically insulating flange and has no electrical creepage at the interface between the flange and the conductive connection.

4. The device according to claim 2 or 3, characterized in that, It includes at least one additional printed circuit board, the two printed circuit boards being electrically connected by means of conductive elements embedded in a portion of the flexible portion.

5. The device according to claim 1 or 2, characterized in that, It includes at least one sealed feedthrough through the wall of the electrically insulating housing, the sealed feedthrough comprising: - At least one conductive connection having at least one portion embedded in the at least one printed circuit board. - An electrically insulating flange made of polymer material surrounds the conductive connection, and there is no electrical creepage at the interface between the flange and the conductive connection; the electrically insulating flange made of polymer material is part of the electrically insulating shell made of polymer material.

6. The device according to any one of the preceding claims, characterized in that, At least one conductive element is contained in a multistranded conductor covered by at least one electrically insulating protective sheath made of polymer material.

7. The device according to any one of the preceding claims, characterized in that, At least one of the electronic components is a self-inductor coil designed to receive or transmit information and / or energy via magnetic coupling with a device located outside the electrically insulating housing made of polymer material; the self-inductor coil is embedded in the at least one printed circuit board.

8. The device according to any one of the preceding claims, characterized in that, The electrically insulating housing, made of polymer material, includes at least one hole that completely passes through the electrically insulating housing made of polymer material; the hole is manufactured such that it does not introduce any electrical creepage.

9. The device according to any one of the preceding claims, characterized in that, The at least one printed circuit board includes at least two substantially identical self-inductance coils embedded in the at least one printed circuit board.

10. The device according to any one of the preceding claims, characterized in that, The at least one printed circuit includes a superparamagnetic composite material; the superparamagnetic composite material is fully embedded in the at least one printed circuit board.

11. The device according to any one of the preceding claims, characterized in that, At least one of the electronic components is a planar self-inductance coil that is fully embedded in the printed circuit board and generated by the arrangement of the wiring traces of the printed circuit board.

12. The device according to any one of the preceding claims, characterized in that, The at least one printed circuit board is made of the same material as the electrically insulating housing.

13. The device according to any one of the preceding claims, characterized in that, The electrically insulating housing, made of polymer material, includes at least one epoxy resin portion.

14. The device according to any one of the preceding claims, characterized in that, The electrically insulating shell comprises at least two distinct parts, the polymer materials of which have substantially the same chemical composition, but one part is filled with a substance that makes its laser energy absorption rate at least 10 times, or even 100 times, or even 1000 times that of the other part.

15. The device according to claim 14, characterized in that, The mass filling rate of the absorbent material is less than or equal to 1%, or even less than 0.1%, or even less than 100 ppm.

16. The device according to claim 14 or 15, characterized in that, The absorbent material is carbon black.

17. The device according to any one of the preceding claims, characterized in that, Components made of polymer materials are assembled, in whole or in part, by laser welding.

18. The device according to any one of the preceding claims, characterized in that, It is biocompatible and is used as an active implantable medical device.

19. An application of the device according to claim 18 for transdermal energy transfer, wherein the active implantable medical device is capable of capturing electromagnetic energy supplied by an external source without any puncture skin connection.

20. An application of the device according to any one of claims 1 to 18 for non-contact measurement of the mass of superparamagnetic materials as part of rapid in vivo or in vitro biomedical diagnostics.

21. An apparatus according to any one of claims 1 to 18 for industrial or medical applications of magnetic field or current measurement, wherein non-contact measurement of at least a static component of the magnetic field is performed.

Images