System and method for sensing position and force of catheter

Abstract

The invention discloses a system and method for sensing the position and force of a catheter. A position sensor for measuring a signal indicative of a position and / or orientation of a distal end of a catheter and a method of manufacturing the same are disclosed. The position sensor includes a flexible circuit board (FCB) and at least three surface mount coil arrangements (SMD coils) arranged thereon for sensing different aspects of one or more magnetic fields indicative of the position and / or orientation of the catheter distal end. The FCB is disposed at the sensor in a folded / rolled state such that flux axes of at least three of the SMD coils are non-coplanar so that at least one of the orientation and position of the sensor relative to one or more magnetic field sources can be determined using signals measured by the at least three SMD coils.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 523,440, filed on June 27, 2023, entitled “A SYSTEM AND METHOD OF SENSINGCATHETER'S LOCATION AND FORCE,” which is incorporated herein by reference. Technical Field

[0003] The present invention is in the field of catheters, and in particular relates to systems and methods for sensing the position of a catheter and the forces exerted by the catheter. Background Art

[0004] In various therapeutic and diagnostic procedures, a catheter / probe is inserted into a patient's body (e.g., a cardiac chamber) and brought into contact with body tissue therein. Typically, in such procedures, it is necessary to determine the position of the catheter in the body (i.e., the position where the distal end of the catheter engages the body tissue) and the pressure applied by the catheter to the tissue.

[0005] Catheters with integrated position and pressure sensors for sensing the position of the catheter and the pressure / force applied by the catheter at the contact area with the tissue are generally known. Such catheters generally utilize inductive coils to determine the position of the catheter within the body and / or the pressure / force applied by the catheter to the body tissue engaged therewith.

[0006] Conventional technology for such catheters typically utilizes a wound coil into which a ferrite core can be manually inserted after winding. The coil manufactured in this manner is then soldered to a cable that carries the coil signal to processing circuitry and assembled within the catheter body. Summary of the invention

[0007] The catheter art requires physically flexible and sensitive catheters with compact / narrow dimensions that are capable of providing accurate feedback regarding the catheter's position in the body, the contact interface between the catheter and tissue, and the forces (eg, vectors) applied therebetween.

[0008] U.S. Patent No. 8,535,308 and U.S. Patent Application No. US2020 / 015693, both assigned to the assignee of the present application, disclose configurations of such catheters, for example utilizing sensing circuits having several coils for sensing the position and orientation of the catheter body and the forces applied by the catheter at the interface with the tissue.

[0009] One challenge in the field of such catheters is to fit accurate position and force sensors within the narrow body of the catheter, which typically has only a few millimeters in transverse dimensions. In practice, the manufacture of relatively compact coils of suitable sensitivity and size for such catheters, as well as the assembly and electrical connection of these coils within the catheter body, typically involves delicate manual operations that are time consuming, costly, and may be limited by the compactness and precision that can be achieved.

[0010] Therefore, there is a need in the art for more efficient, cost-effective techniques for manufacturing such catheters and for manufacturing small, highly sensitive coils (i.e., having a high induced voltage in response to a magnetic field; i.e., high impedance) suitable for position and / or force sensing in catheters such as those disclosed above. In addition, there is a need in the art for automated manufacturing techniques for such coils to produce standardized coils with less variability between manufactured coils of the same design. In addition, to facilitate further advancement in the catheter field, there is a need in the art for facilitating size reduction and / or impedance / induced voltage improvement so as to improve one or both of the sensitivity and flexibility of the catheter and / or reduced size.

[0011] The present invention accomplishes this by providing a novel position sensor that is particularly suitable for locating a high impedance (high induced voltage) sensor coil within the narrow dimensions of a catheter body.

[0012] Thus, according to a broad aspect of the invention, there is provided a position sensor adapted to measure a signal indicative of at least one of a position and an orientation of the sensor relative to one or more magnetic fields. The position sensor comprises a circuit board, and at least three coils located on the circuit board and arranged to sense different aspects of a magnetic field, the different aspects being indicative of at least one of a position and an orientation of the sensor relative to an external magnetic field. According to some aspects of the invention, the circuit board is a flexible circuit board (FCB) and the at least three coils are at least three surface mounted coil devices (SMD coils) mounted on the FCB via surface mount technology (SMT). The FCB is arranged at the sensor in a folded / rolled state so that the flux axes of at least three of the SMD coils mounted on its surface are not coplanar, thereby enabling the use of signals obtained from the at least three SMD coils to measure at least one of an orientation and a position of the sensor relative to one or more magnetic field sources.

[0013] According to some embodiments, the positioning sensor is adapted to measure a signal indicative of the orientation of the sensor relative to a first magnetic field source, the first magnetic field source being located in front of the position sensor (e.g., in front of a longitudinal axis of the first magnetic field source relative to an axis about which the FCB is folded). The at least three SMD coils include three SMD coils arranged on the FCB such that when the FCB is disposed at the sensor in a folded / rolled state, the flux axes of the three SMD coils are parallel to each other and not coplanar. This thereby enables the determination of two orientation angles relative to the first magnetic field source, which is located in front of the three SMD coils along the approximate direction of their flux axes, using the signals obtained from the three SMD coils.

[0014] In some embodiments of the present invention, the three SMD coils are surface mounted to the surface of the FCB via surface mounting technology so that their flux axes are oriented parallel to the surface of the FCB on which they are mounted. The FCB is then arranged at the sensor in a folded / rolled form so that the folding / winding axis of the folded / wound form of the FCB is substantially parallel to the parallel flux axes of the three SMD coils thereon.

[0015] In some embodiments of the present invention, the position sensor is adapted to measure a signal indicating the position and orientation of the sensor relative to one or more second magnetic field sources. The at least three SMD coils include three SMD coils arranged on the FCB so that when the FCB is folded at the sensor, the flux axes of the three SMD coils span three-dimensional (3D) coordinates. This makes it possible to use the signals obtained from the three SMD coils to determine the position and orientation of the sensor relative to the one or more magnetic field sources. In some embodiments, two of the at least three SMD coils of the position sensor are surface mounted to the surface of the FCB via surface mounting technology and are positioned on the FCB so that their flux axes are oriented vertically relative to the FCB surface. Therefore, when the FCB is arranged at the sensor in a folded / rolled-up state, the flux axes of the two SMD coils are not parallel. The third SMD coil of the at least three SMD coils is surface mounted to the surface of the FCB via surface mounting technology with its flux axis parallel to the FCB surface. This makes it possible to use the signals obtained from the three SMD coils to determine the position and orientation of the sensor relative to the one or more external magnetic field sources.

[0016] According to some embodiments of the present invention, the position sensor comprises at least five SMD coils surface mounted to one or more FCBs of the sensor. A first subset of three SMD coils of the at least five SMD coils is arranged so that when the FCB is arranged at the sensor in a folded / rolled state, the flux axes of the three SMD coils are parallel to each other and not coplanar, so that the two orientation angles of the sensor relative to a first magnetic field source can be determined using the signals obtained by the three SMD coils, and the first magnetic field source is located in front of them along the approximate direction of the flux axes of the three SMD coils. In addition, a second subset of three SMD coils of the at least five SMD coils is arranged so that when the FCB is arranged at the sensor in a folded / rolled state, the flux axes of the three SMD coils span 3D coordinates. This makes it possible to determine the position and orientation of the sensor relative to one or more second magnetic field sources using the signals obtained from the three SMD coils of the second subset.

[0017] According to some embodiments, at least one of the at least three SMD coils of the sensor includes a coil portion and at least one surface mount portion disposed from at least one respective side of the coil portion. The coil portion includes a ferrite core and a conductive winding arrangement disposed in a spiral directly above an outer surface of the ferrite core, the pitch of the spiral not exceeding 13 μm, and in some embodiments not exceeding 12 μm, so that the SMD coil has a compact size and high impedance. In some specific implementations, the ferrite core may, for example, include a relative magnetic permeability μm of at least about 100. r The material has a relative magnetic permeability that is stable within a temperature range of about 20° C. to 60° C. with a tolerance of ±0.3%. This enables consistent magnetic field measurements during operation under variable temperature conditions within the temperature range. In some implementations, the conductive winding arrangement is fabricated directly on the outer surface of the ferrite core using photolithography.

[0018] In some embodiments of the position sensor of the present invention, at least one of the at least three SMD coils is mounted on the FCB with its magnetic flux axis oriented flat / parallel relative to the surface of the FCB. The at least one SMD coil includes a coil portion having a conductive winding arrangement and at least two SMT mounting portions, the at least two SMT mounting portions being arranged from opposite sides of the coil portion and having at least two corresponding electrical contacts, the at least two corresponding electrical contacts being electrically coupled to the FCB using SMT electrical connections and being electrically connected to opposite ends of the conductive winding arrangement, respectively.

[0019] In some embodiments of the position sensor of the present invention, at least one of the at least three SMD coils is mounted with its magnetic flux axis in a vertical / perpendicular orientation relative to the surface of the FCB. The at least one SMD coil comprises a coil portion and at least one SMT mounting portion, the coil portion having a conductive winding arrangement, the at least one SMT mounting portion being arranged from at least one side of the coil portion and having at least two electrical contacts, the at least two electrical contacts being electrically coupled to the FCB via SMT electrical connections and being electrically connected to opposite ends of the conductive winding arrangement, respectively. According to another broad aspect of the present invention, a medical device / apparatus is provided, which comprises a position sensor constructed and operated according to the present invention as described above, which will be further described in more detail below. According to some embodiments, the medical device is a catheter having an elongated housing, the elongated housing comprising a main section and a terminal section, the main section having a longitudinal axis, the terminal section being flexibly coupled at a distal end of the main section and comprising a first magnetic field source. The position sensor is housed at the main section of the elongated housing so that the FCB is folded / rolled up around an axis parallel to the longitudinal axis of the catheter. As described above, the first subset of coils of the sensor facilitates determining the orientation of the tip segment relative to the main segment of the housing based on measurements of a magnetic field from a first magnetic field source located at the tip segment. As described above, the second subset of coils of the sensor facilitates determining the position and orientation of the main segment relative to one or more external second magnetic field sources (which may be located external to the medical device).

[0020] According to yet another broad aspect of the present invention, there is provided a method of manufacturing a magnetic position sensor suitable for use in a medical device. The method comprises:

[0021] i. Provide flexible printed circuit board (FCB);

[0022] ii. Providing at least three surface mounted coil devices (SMD coils);

[0023] iii. Mounting the at least three SMD coils to the

[0024] FCB;

[0025] iv. folding the FCB having the at least three SMD coils thereon into a tubular form so that the magnetic axes of the at least three SMD coils are not coplanar and thereby providing a magnetic field sensed by the at least three SMD coils from one or more magnetic field sources so as to be capable of being used to measure at least one of the position and orientation of the sensor relative to the source.

[0026] In some embodiments, such as where the medical device is a catheter having a tubular shaped body having a characteristic inner diameter of about 2.5 mm or less, the folding is performed such that the diameter of the FCB after being folded is less than the characteristic inner diameter of the body of the catheter; and the method includes placing the folded FCB within the body.

[0027] According to some embodiments, the magnetic position sensor is adapted to measure a signal indicative of the orientation of the sensor relative to a magnetic field source. The mounting of the at least three SMD coils includes mounting three of the SMD coils on the FCB such that their flux axes are parallel to each other and are not coplanar when the FCB is folded into a tubular form, thereby enabling the determination of two orientation angles of an associated magnetic field source located in front of the three SMD coils along the approximate direction of their flux axes using the signals obtained from the three SMD coils.

[0028] According to some embodiments, the magnetic position sensor is adapted to measure signals indicative of the position and orientation of the sensor relative to one or more external magnetic field sources. The mounting of the at least three SMD coils includes mounting three of the SMD coils on the FCB such that when the FCB is folded into a tubular form, the magnetic flux axes of the three SMD coils span the 3D coordinates, thereby enabling the position and orientation of the sensor relative to the external magnetic field sources to be determined using the signals obtained from the three SMD coils.

[0029] According to some embodiments, the magnetic position sensor is adapted to measure a signal indicative of the orientation of the sensor relative to a first magnetic field source and a signal indicative of the position and orientation of the sensor relative to one or more second external magnetic field sources. The at least three SMD coils include at least five SMDs, and the mounting includes mounting the at least five SMD coils so that the following arrangement of its magnetic flux axes is obtained when the FCB is folded into a tubular form:

[0030] - a first subset of at least three SMD coils of the at least five SMD coils having flux axes that are parallel to each other and not coplanar, thereby facilitating the determination of two orientation angles relative to a first magnetic field source using signals obtained from the first subset when the first magnetic field source is located in front of the three SMD coils of the first subset along the general direction of the parallel flux axes of the three SMD coils;

[0031] - A second subset of at least three of the at least five SMD coils has a magnetic flux axis spanning a 3D coordinate, thereby facilitating use of signals obtained from said first subset to determine the position and orientation of the sensor relative to one or more external magnetic field sources.

[0032] In some embodiments, mounting is performed using surface mount technology and includes at least one of the following:

[0033] - Mounting at least two SMD coils with their flux axes oriented vertically relative to the FCB surface;

[0034] mounting at least one SMD coil with its flux axis oriented parallel to the FCB surface;

[0035] so that when the FCB is in a folded state, the flux axes of the at least two SMD coils and the flux axis of the at least one SMD coil span across 3D coordinates; and

[0036] - mounting at least three SMD coils with their flux axes oriented parallel to the FCB surface, such that when the FCB is folded about an axis parallel to the flux axes, the flux axes of the three SMD coils are parallel and non-coplanar;

[0037] In some specific implementations, providing at least three SMD coils includes manufacturing at least one of the SMD coils using the photolithography method of the present invention, thereby forming a spiral winding directly on the ferrite core of the coil. The photolithography method includes, for example:

[0038] a. applying a photoresist layer to cover at least the tubular section of the ferrite core;

[0039] b. applying photolithography to pattern the photoresist layer, thereby forming a spiral pattern on the tubular segment covered by the photoresist layer; and

[0040] c. Electroplating the outer surface layer of the ferrite core at the exposed areas of the spiral pattern to form a conductive spiral winding directly on the outer surface layer of the tubular section of the ferrite core.

[0041] In some embodiments, the photolithographic manufacturing method is further characterized by one or more of the following:

[0042] - the photolithography method is suitable for manufacturing high-density conductive windings, and the pitch of the spiral pattern formed by photolithography (and the pitch of the corresponding conductive spiral winding) is about 10 μm or less;

[0043] - The ferrite core comprises a magnetic material having a relative magnetic permeability μ of at least 100 r A fully sintered magnetic material; and wherein the photolithography is performed using a photolithography light source having a light power density (LDP) and a wavelength suitable for patterning the photoresist while not causing significant damage to the ferrite core;

[0044] - applying the photoresist layer comprises applying a dry photoresist layer having a thickness of at least 8 μm, thereby enabling the outer surface layer to be electrolytically plated while producing a narrow line width of the spiral conductive winding with a small pitch between adjacent lines and preventing spreading of the electrolytic plating between adjacent lines;

[0045] - the photolithographic manufacturing method includes producing a seed layer before electroplating, thereby producing a seed layer on at least a portion of the ferrite core in order to increase the surface conductivity of the ferrite and facilitate electroplating;

[0046] - a photolithographic manufacturing method comprising, after electroplating, removing the remaining photoresist material between the conductive windings of the helical coil;

[0047] -The ferrite core is provided with at least one surface mounting portion arranged from at least one corresponding side thereof; photoresist, photolithography and electroplating are also applied to form one or more conductive couplings between at least one end of the conductive spiral coil and one or more designated locations on the at least one surface mounting portion, thereby forming one or more SMT contacts.

[0048] To this end, the inventors of the present invention have also conceived novel and inventive configurations of surface mounted coil devices (SMD coils) and methods of manufacturing such SMD coils to facilitate the high impedance and small size characteristics of SMD coils, as is generally desired for many sensor applications and in particular for catheter sensing systems. In this regard, the desired characteristics of such SMD coils include, among others, high density spiral windings densely packed on a tubular high permeability and electrically insulating magnetic core, and more specifically high count spiral windings / turns per unit length of the tubular magnetic core and per winding layer thereon. For example, what is achievable by the photolithography-based coil manufacturing method of the present invention is a high density winding with a winding count of at least 100 turns to 150 turns per millimeter of core length (e.g., per winding layer) directly on the magnetic core. In addition, the wire wound coil manufacturing technique of the present invention facilitates high density windings with multiple winding layers and a winding count of approximately 80 turns per layer per millimeter of core length (e.g., 77 turns-83 turns per layer per millimeter) directly on the magnetic core. Furthermore, the coil manufacturing technique of the present invention facilitates the manufacture of windings on high permeability (and electrically insulating) tubular magnetic cores having relative permeabilities of the order of hundreds or more (e.g., relative permeabilities of at least 100 μm). r ). Here, the relative magnetic permeability μ r It is a dimensionless number that represents the ratio of the magnetic permeability of the magnetic body μ to the magnetic permeability of the space μ0, that is, μ r =μ / μ0.

[0049] In this regard, it should be understood that the term tubular as used herein generally refers to a body having a longitudinal axis of symmetry for rotation in discrete or continuous groups (i.e., generally any shape, such as a cylinder or cone having a longitudinal axis of symmetry, for example, along its z-axis, and a cross-section in the xy plane that may be smooth, such as circular or elliptical, or polygonal, such as triangular, rectangular, etc.).

[0050] In this regard, aspects of the present invention are particularly directed to a spiral SMD coil having a tubular magnetic core, wherein one or more spiral conductive windings are arranged on the tubular magnetic core (in the case of multiple spiral conductive windings, the multiple spiral windings may be connected in series or in parallel and may be arranged concentrically around the magnetic core). The spiral conductive winding may have an elliptical, circular, polygonal cross-sectional shape, which generally follows the cross-section of the magnetic core. In this regard, it should also be noted that the spiral construction of the spiral SMD coil of the present invention is considered to be superior to other types of coils, such as planar coils (e.g., planar concentric coils) or "air core" coils (i.e., without a core of magnetic material). These advantages are particularly significant in the case of high inductance coils (e.g., coils with higher reactance / induced voltage at a specified frequency) of compact cross-sections, such as in the case of compact sensing systems (e.g., those used in catheters). This is because the spiral SMD coil of the present invention can be manufactured to have a smaller size and / or a smaller cross-section than a planar coil as a planar concentric coil (where the magnetic core (if present) is located below the planar coil), based on a similar voltage induced by an external magnetic field (e.g., a time-varying magnetic field outside the coil). Furthermore, the spiral SMD coils of various embodiments of the present invention are designed for surface mount assembly on electronic circuits, thus enabling more efficient, faster, more reliable and more cost-effective assembly of the coil on the sensor circuit. Additionally, in the manufacturing techniques of the present invention, the compact spiral SMD coils are manufactured with the windings formed / wound on a magnetic core (unlike some conventional techniques of compact high winding count coil manufacturing which require an additional post-winding (manual) step of inserting the core into the windings). This in turn facilitates a more cost-effective manufacturing process for the compact coils, with uniform production rates.

[0051] It should be noted that the term magnetic core, which is used interchangeably herein, and the terms ferrite and ferrite core are used herein to refer to a block / body of a magnetic material / composition or mixture, wherein the relative magnetic permeability μ r >>1. The terms substantially pure magnetic material and pure ferrite are used in this article to refer to materials with a relative magnetic permeability μ r >>1 A block / body of material which is not substantially mixed / compounded with other materials. This is in particular to distinguish such magnetic material from compounds / mixtures of magnetic material with non-magnetic materials (e.g. epoxy resins) which are often used to improve properties of ferrite cores other than their permeability μ, such as core formation at low temperatures, at the expense of the resulting permeability of cores made from such compounds / mixtures.

[0052] In this regard, as will be appreciated by those skilled in the art, magnetic materials suitable for use in the SMD coils of the present invention are typically of a type having the magnetic properties of so-called soft ferrites (ie, having a relatively low coercivity, making them suitable for electrical applications such as inductors).

[0053] Cores of substantially pure magnetic material are typically sintered to form a solid structure, however the sintered structure remains relatively weak / fragile and easily damaged during the manufacturing process. For example, a bulk of pure soft magnetic material / core may be susceptible to structural damage (fracture / breakage) under pressure applied thereto during the physical winding process. In another example, the surface composition and crystal structure of a ferrite core (e.g., substantially pure / unmixed magnetic material) may be relatively easily damaged when exposed to high intensity light, such as when a laser is used to ablate copper from the ferrite surface, which may produce surface temperatures greater than 1000°C, thereby causing a transformation of the material's conductive properties, such as converting it from an electrically insulating material to a relatively conductive material, which may be less undesirable for electrical applications such as example / transformer / filter coils, etc. Therefore, many conventional techniques for coil manufacturing, particularly for tubular coil manufacturing, support the use of a mixture / composite of magnetic materials with other materials (e.g., structurally reinforced materials) in order to improve the physical strength of the core composited in this manner and / or stabilize its resistivity against the manufacturing process and / or other environmental conditions at the expense of reducing its overall magnetic permeability. For this reason, standard techniques for manufacturing chip-scale inductors (several millimeters in size) with fully sintered ferrite cores are limited in terms of the maximum allowable aspect ratio between the core length and its lateral dimensions (the core cannot be too long because it will break during winding), and are also limited in terms of the minimum allowable diameter of the winding wire, which is typically not less than 20μm-25μm (because thinner wires will break due to the tensile forces applied to them during the conventional winding process).

[0054] Thus, in light of the foregoing, conventional techniques for manufacturing surface mountable spiral coils are limited and not well suited for manufacturing compact spiral SMD coils having high density windings on cores of high permeability (e.g., substantially pure) magnetic material (particularly on "soft" cores), and are also associated with high costs of manufacturing such coils and uneven yields.

[0055] Advantageously, the present invention provides novel and inventive spiral SMD coil manufacturing techniques and novel and inventive spiral SMD coil configurations that help overcome some or all of the above-mentioned deficiencies of conventional techniques, enabling substantially automated manufacturing of compact spiral SMD coils having high winding density (with winding pitches as low as a few microns) on high permeability magnetic materials, while alleviating some of the geometric limitations imposed by conventional techniques on the manufacture of such coils (such as limitations on allowable aspect ratios), while advantageously producing more uniform production rates.

[0056] Therefore, according to a broad aspect of the present invention, a surface mounted coil device (SMD coil) is provided. The SMD coil comprises a coil portion having a ferrite core; a conductive winding device comprising a conductor arranged in a spiral line around the ferrite core around the longitudinal axis of the ferrite core. The SMD coil also comprises at least one surface mounting portion, which is arranged from at least one respective side of the coil portion and has at least one electrical contact coupler for electrically coupling the conductive winding arrangement of the coil portion to a circuit via surface mounting technology (SMT). According to some embodiments of the present invention, the continuous wire of the conductive winding device is directly wound on the outer surface layer of the ferrite core, whereby the pitch of the conductive winding in the spiral conductive winding device does not exceed 12 or 13 μm. Thus, an SMD coil having compact size and high impedance (generating a high magnetic field induced voltage) is obtained, which is particularly suitable for SMT installation in a magnetic field sensor.

[0057] According to some embodiments of the present invention, the SMD coil is configured to be mounted flat / parallel on the surface of the circuit. In such embodiments, at least two SMT mounting portions are arranged from opposite sides of the coil portion, and each of them includes at least one electrical contact electrically connected to the coil portion. The conductive winding arrangement starts from its respective end. The SMT mounting portion with the electrical contacts is therefore suitable for SMT mounting on a circuit board, so that the SMD coil can be mounted on the circuit board surface with its flux axis substantially parallel to the surface of the circuit board.

[0058] Alternatively or additionally, according to some embodiments of the present invention, the SMD coil is configured for vertical / perpendicular mounting on the surface of the circuit board. In such embodiments, at least one SMT mounting portion may be a single SMT mounting portion including at least two electrical contacts, the at least two electrical contacts being electrically connected respectively near approximately opposite ends of the SMT mounting portion. The conductive winding arrangement is suitable for SMT mounting on a circuit board. The SMD coil can thus be mounted to the surface of the circuit board surface with its magnetic flux axis substantially perpendicular to the circuit surface.

[0059] According to some embodiments of the present invention, the ferrite core of the SMD coil comprises a ferrite core having a relative magnetic permeability μ rThe material has a relative magnetic permeability of at least 100 and is stable (with ±0.3%) over a temperature range of about 20° C. to 60° C. This enables consistent magnetic field measurements during operation under variable temperature conditions within the temperature range.

[0060] According to another broad aspect of the present invention, there is provided a method for manufacturing a spiral coil directly on a ferrite core so that the spiral coil surrounds the ferrite core. The method comprises:

[0061] a. Providing a ferrite core having a tubular shape;

[0062] b. applying a photoresist layer to the peripheral portion of the surface of the ferrite core to cover at least the tubular section thereof from all sides;

[0063] c. applying photolithography to pattern the photoresist layer to form a spiral pattern on the tubular section of the ferrite core covered by the photoresist layer; and

[0064] d. electroplating the outer surface layer of the ferrite core at the exposed area of ​​the spiral pattern to form a conductive spiral coil on the outer surface layer of the ferrite core in the form of the spiral pattern.

[0065] The method according to some embodiments of the present invention is suitable for manufacturing a conductive spiral coil with a high density of windings, whereby the pitch of the spiral pattern and, accordingly, the pitch of the conductive spiral coil is about 10 μm or less (even as low as 8 μm).

[0066] According to some embodiments of the method, the ferrite core includes or consists of a fully sintered magnetic material having a relative magnetic property. r In the order of at least 100. To this end, the above-described lithography operations may utilize a lithography light source that provides a light power density (LPD) and wavelength that is suitable for patterning the photoresist while not causing significant damage to the ferrite core.

[0067] In some implementations of the method, preparing the photoresist layer includes applying a dry photoresist layer at least 8 μm thick. This thereby enables the electroplating operation to produce narrow line widths of spiral conductive coils with small pitch between adjacent lines while preventing electroplating diffusion between lines.

[0068] In some implementations, the method further includes fabricating a seed layer on at least a portion of the ferrite core to increase the surface conductivity of the ferrite, thereby facilitating electroplating. Additionally or alternatively, in some implementations, the method removes remaining photoresist material between the conductive windings of the spiral coil after electroplating.

[0069] According to some embodiments of the present invention, the method is suitable for manufacturing other components of surface mounted coil devices (SMD coils). The process may also include one or more of the following items:

[0070] - In operation a. the ferrite core is provided with at least one surface mounting portion arranged from at least one respective side thereof;

[0071] - in operation b. the photoresist layer is also applied to a surface area of ​​the at least one surface mounting portion, the surface area extending from the ferrite core toward a designated electrical contact location on the surface mounting portion;

[0072] - in operation c. applying photolithography to pattern the photoresist layer at a surface area of ​​at least one surface mounting portion to form a patterned path connecting one end of the spiral pattern to a designated position at the surface mounting portion; and

[0073] - In operation d, electroplating is applied to the patterned path to form a conductive coupling between the end of the conductive spiral coil and a designated location at the surface mount portion.

[0074] According to some embodiments of the present invention, the method is suitable for manufacturing a surface mounted coil device (SMD coil) suitable for flat / parallel mounting on a circuit surface. In such embodiments, the ferrite core can be provided with at least two surface mounting portions arranged from at least two corresponding sides thereof. Therefore, operations (b.) to (d.) can be applied to form corresponding conductive couplings between two specified positions at the corresponding surface mounting portions and the corresponding ends of the conductive spiral coil. This thereby enables the SMD coil to be mounted flat / parallel on the surface of a circuit board, wherein the two specified positions at the two surface mounting portions respectively provide electrical contact between the circuit and the corresponding ends of the conductive spiral coil.

[0075] Alternatively or additionally, according to some embodiments of the present invention, the method is suitable for manufacturing a surface mounted coil device (SMD coil) suitable for being mounted vertically / perpendicularly on the surface of a circuit board. In this case, the ferrite core may be provided with at least one / single surface mounting portion arranged from one side thereof. In this case, the ferrite core may also include a conductive body path that passes through the body of the ferrite core from the electrical contact of the surface mounting portion located at the one corresponding side toward the opposite side of the conductive area of ​​the exposed conductive path of the ferrite core. Therefore, in such embodiments, operations (b.) to (d.) of the method may be used to form:

[0076] (i) conductive coupling between a designated location at the surface mounting portion and a corresponding end of the conductive spiral coil located proximal to the surface mounting portion; and

[0077] (ii) conductive coupling between the exposed conductive region of the conductive body path and a corresponding end of the conductive spiral coil located proximate to the exposed conductive region;

[0078] Methods according to such embodiments enable vertical / perpendicular mounting of an SMD coil on a circuit, wherein electrical contacts at a single surface mount portion provide electrical contact between the circuit and respective ends of the conductive spiral coil.

[0079] According to another broad aspect of the present invention, there is provided a method for manufacturing a surface mounted coil device having a spiral coil directly on a ferrite core around a ferrite core. The method according to embodiment 1 comprises:

[0080] a. Providing a ferrite core having a tubular shape; and

[0081] b. Winding a wire around the ferrite core to form a spiral coil on the circumference of the ferrite core;

[0082] c. Attaching one or more surface mount parts to one or more corresponding sides of the ferrite core, and electrically connecting both ends of the helical coil to two corresponding electrical contacts of the one or more surface mount parts.

[0083] According to the invention, the wire used in the winding has a characteristic diameter of the order of about 12 to 13 micrometers or less. This therefore facilitates high density windings on the ferrite core and correspondingly improves the coupling of the coil to the magnetic field (high induced voltage).

[0084] According to some embodiments, the ferrite core comprises a fully sintered magnetic material (ie, without non-magnetic structural reinforcement additives), thereby providing a relative magnetic permeability μ r At least on the order of 100 or more.

[0085] In yet another broad aspect of the present invention, there is provided a surface mounted coil device (SMD coil) comprising a coil portion having a ferrite core and a conductive winding arrangement. The conductive winding arrangement comprises a conductor arranged in a spiral manner around the longitudinal axis of the ferrite core. The SMD coil further comprises at least one surface mounting portion arranged from at least one respective side of the coil portion and having at least one electrical contact coupler for electrically coupling the conductive winding arrangement of the coil portion to a circuit via surface mounting technology (SMT). The SMD coil is manufactured according to any of the above-described methods of the present invention such that a continuous wire of the conductive winding arrangement is directly wound / arranged on an outer surface layer of the ferrite core, wherein the pitch of the spiral wire of the conductive winding arrangement does not exceed 13 μm and in some cases does not exceed 12 μm. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] In order to better understand the subject matter disclosed herein and to illustrate how the subject matter may be implemented in practice, various embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which:

[0087] Figures 1A to 1C are schematic perspective views of spiral surface mount coil devices (SMD coils) constructed according to three embodiments of the present invention;

[0088] Figure 2 is a flow chart of a photolithography-based manufacturing method of a spiral SMD coil according to an embodiment of the present invention;

[0089] Figure 3 is a schematic diagram of an example of a photolithographic coil manufacturing system according to an embodiment of the present invention;

[0090] Figure 4 is a flow chart of a method for manufacturing a compact spiral SMD coil using wire winding according to an embodiment of the present invention;

[0091] FIG. 5A to FIG. 5D , FIG. 6A to FIG. 6D , 7A to 7D and FIG. 8A to FIG. 8D is a schematic diagram of a position sensor 100 according to several embodiments of the present invention;

[0092] 9A to 9C is a schematic diagram of a medical device / apparatus incorporating a position sensor according to several embodiments of the present invention; and

[0093] Fig. 10A and Fig. 10B A method 400 for manufacturing a magnetic position sensor according to an embodiment of the present invention is shown, whereby Fig. 10A is a flow chart of the method, and Fig. 10B Shown is the folding of the circuit board of the sensor during manufacturing. DETAILED DESCRIPTION

[0094] Reference now Figure 1A , wherein a perspective view of a spiral surface mounted coil device (SMD coil) 10 according to an embodiment of the present invention is shown. The SMD coil 10 generally comprises: a coil portion C having a core FC of magnetic material (also interchangeably referred to herein as a ferrite core); and a conductive winding arrangement CW comprising a conductor arranged in a spiral around the magnetic core FC along its longitudinal axis FX. The SMD coil 10 also comprises one or more surface mounting portions SM (generally comprising non-magnetic materials such as copper and tin, and / or magnetic nickel and tin) arranged from at least one respective longitudinal end of the coil portion C and having at least two electrical contact couplers SMC thereon, which are conductively coupled near / at respective ends of the conductors of the conductive winding arrangement CW of the coil portion C and are suitable for electrically coupling the conductive winding arrangement CW to a circuit via surface mounting technology (SMT). Preferably, in some embodiments, the size, location and material of these contacts are configured not to shield external magnetic fields entering the magnetic core, and may even assist in concentrating the magnetic field to the magnetic core.

[0095] Specifically in the spiral SMD coil 10 according to this embodiment of the present invention, the continuous conductor of the conductive winding arrangement CW has a spiral geometry and is wound / wrapped directly over the outer surface of the magnetic core FC, for example, on the exposed surface of the magnetic material of the magnetic core FC or on a seed layer that can be manufactured on the magnetic material of the magnetic core FC, for example, so as to facilitate the conductivity of the magnetic core surface to be sufficient for the electroplating process, by which the conductive winding arrangement CW is manufactured on the magnetic core FC according to some embodiments of the present invention, as described below.

[0096] It should be understood that in the context of the present application, phrases related to winding and / or wrapping are used to designate the formation of a conductive helical structure (conductive winding arrangement CW) around a magnetic core FC, regardless of the specific method used to manufacture the structure, whether by Figure 2 and 3 lithography as exemplified in the example, or by Figure 4 The wire is wound around the magnetic core as shown in the example.

[0097] Furthermore, the spiral SMD coil 10 according to this embodiment of the invention is specifically configured to produce high inductance and high induced voltage for a specified frequency range, and can be pre-designed for a specified frequency range by appropriately selecting the core material according to the permeability of the core material at the specified frequency range, as well as the cross-sectional area of ​​the core FC and the number of windings, by which the induced voltage and inductance of the coil can be defined. In a specific non-limiting example, the spiral SMD coil 10 can be specifically configured to produce high inductance and reactance for frequencies in the kHz range (e.g., 1 kHz to 16 kHz), which can be particularly suitable for use in magnetic field localization and force sensors, such as those used in intra-catheter applications.

[0098] In this regard, in order to facilitate the operation under the operating temperature conditions [T min , T max ] range, the magnetic material of the core C is preferably selected so that its magnetic permeability μ is within the required operating temperature range [T min , T max ] is basically stable, and the magnetic permeability μ r The change in the temperature range [T min =20C, T max =60°C] by no more than, for example, ±0.3% (eg, no more than about 160 ppm / °C). In this regard, it is noted that in general, the shorter the core along its longitudinal axis, the higher its temperature coefficient can be without affecting stability.

[0099] In one specific non-limiting example, the magnetic permeability μ of the magnetic material of the core FC is substantially stable (e.g., within the tolerance) over a temperature range between approximately 20°C and 60°C, thereby facilitating accurate operation of a sensor utilizing the spiral SMD coil 10 when deployed in a catheter, such as an ablation catheter, the surgical function of which may produce temperature variations within the temperature range.

[0100] Furthermore, according to an embodiment of the present invention, in order to facilitate high inductance / induced voltage and compact size of the spiral SMD coil 10 of the present invention, the magnetic material of the core FC is preferably selected such that its magnetic relative permeability μ is rof the order of several hundred (e.g., at least 100) at a specified operating magnetic field range (which may be, for example, in the range of about 1 kHz to 16 kHz). To this end, preferably, in order to obtain such a high magnetic permeability of the core FC, in some embodiments, the magnetic material used in the core FC comprises a sintered / fully sintered magnetic material, or is composed of a sintered / fully sintered magnetic material, such as a ferrite, for example, without a mixture with a large amount of non-magnetic material, such as a structurally reinforcing additive; for example, epoxy resin. Preferably, the magnetic core FC material used is temperature stable (e.g., having a temperature magnetic permeability coefficient of less than 160 ppm / °C) in the temperature range of 20°C to 60°C.

[0101] In addition, preferably, in order to facilitate high inductance / induced voltage of the helical SMD coil 10, the wire spiral of the conductive winding arrangement CW is configured to have a pitch P of no more than 814 μm of the spiral winding / turn. Figure 2 and 3 The described embodiments of the SMD coil manufacturing technique of the present invention facilitate the manufacture of a conductive winding arrangement CW having a winding pitch P of about 8 μm (e.g., having a lateral diameter / width of the wire reduced to 4 μm or even less and a spacing between consecutive turns reduced to 4 μm or even less, resulting in a pitch P of 8 μm or less). In another case, the following reference is made to Figure 4 Embodiments of the described SMD coil manufacturing techniques facilitate winding with a winding pitch P of about 1213 μm (eg, for an insulated wire having a wire width of about 10 μm with about 2 μm-3 μm of electrical insulation / enamel coating therebetween).

[0102] These methods thus enable a high winding count of the helical conductor of the conductive winding arrangement CW per unit length of the core FC, for example using Figure 2 The technology achieves a winding count of about 100 to 150 windings per 1 mm of core length covered by each layer of the conductive winding arrangement CW (typically about 125 windings / mm per layer), and Figure 4 In embodiments of the present invention, about 77 to 83 winding counts per layer are achieved. In both methods, the width of the wire can be of the same order of magnitude as its width, or thicker (e.g., about 4 μm or more) to promote sufficient conductivity and low resistance of the SMD coil despite the narrow width of the wire. In some embodiments, the thickness can be even greater, such as greater than 6 μm, to obtain a further reduction in coil resistivity.

[0103] The above-described construction of the spiral SMD coil of the present invention thus results in a compact size and high inductance / induced voltage SMD coil suitable for SMT mounting in a magnetic field locating sensor adapted to fit in a catheter.

[0104] Now refer to Figure 1B and Figure 1C , which shows the above reference Figure 1A Perspective views of two embodiments of an SMD coil 10 are depicted. Figure 1B Shows Figure 1A The embodiment 10H of the SMD coil 10 shown in FIG. 1 is configured for horizontal mounting on a circuit board CB so that its longitudinal / flux axis FX is substantially parallel to the plane of the circuit board CB (this embodiment 10H is also referred to as a horizontal [spiral] SMD coil hereinafter). Figure 1C An embodiment 10V of an SMD coil 10 is shown, which is configured to be mounted vertically on a circuit board CB so that its longitudinal / magnetic flux axis FX is substantially perpendicular to the face of the circuit board CB (this embodiment 10V is also referred to as a vertical [spiral] SMD coil hereinafter). The accompanying drawings also show possible other configurations / extensions SME of the surface mounting portion SM of the SMD coil 10, which may be an integral part of the surface mounting portion SM or an extension thereof, thereby facilitating mounting the SMD coil 10 of the present invention at any desired angle relative to the circuit board CB. It should be understood that even if not specifically mentioned, the following description Figure 1B and Figure 1C The implementation scheme can also be combined with the above reference Figure 1A All or any suitable combination of the features of the SMD coil 10 described.

[0105] Specific reference Figure 1B , which shows a perspective view; PVa spiral SMD coil 10H is configured for planar / parallel mounting on the surface of a circuit board according to one embodiment of the present invention. CB (or possibly in other directions with optional options) surface mounting configuration SME shown and the perspective view PIV of the mounting illustrate how to orient the SMD coil 10H on the circuit board CB surface mounting direction SM direction, pointing to the specified position of the circuit board CB relative to the spiral SMD coil 10H, also shown in the figure.

[0106] In this embodiment, the spiral SMD coil 10H includes at least two SMT mounting parts SM arranged from opposite ends of the coil part C. Each of the two SMT mounting parts SM includes at least one electrical contact SMC1 and SMC2, which is suitable for SMT mounting on the circuit board CB. The two electrical contacts SMC1 and SMC2 are respectively electrically connected to the conductive winding arrangement CW on the two upper SMT mounting parts SM-from their opposite respective ends, for example via conductive paths; CP contacts the conductive winding arrangement CW from thereon and / or through the respective arranged SMT mounting parts SM with the respective ends. Therefore, in this embodiment, the SMT electrical contacts SMC1 and SMC2 electrically connected to the respective ends of the spiral winding are located on the outer surfaces of the SMT mounting parts SM, which are substantially parallel to each other and substantially parallel to the flux axis FX (for example, 0° or at least less than 45° relative to the flux axis FX, depending on the SME configuration). Therefore, the horizontal spiral SMD coil 10H of this embodiment of the invention is particularly suitable for surface mounting to a circuit board CB, with its flux axis FX substantially parallel to the circuit surface, or at any other suitable angle, typically between 0° and 45°, relative to the circuit surface according to an optional SME configuration.

[0107] Reference now Figure 1C , which shows two perspective views PV1 and PV2 of a vertical spiral SMD coil 10V according to an embodiment of the present invention, the vertical spiral SMD coil 10V being configured for vertical / perpendicular mounting on the surface of a circuit board CB (or possibly in other directions using an optional surface mounting configuration SME shown); and a mounted perspective view PIV, which illustrates how the SMD coil 10V is oriented when disposed on the circuit board CB. The surface mounting direction SM direction pointing to the specified position of the circuit board CB relative to the spiral SMD coil 10V is also shown in the figure.

[0108] In this embodiment, the spiral SMD coil 10V includes at least one SMT mounting portion SM arranged from the end of the coil portion C. The SMT mounting portion SM includes at least two electrical contacts SMC1 and SMC2 suitable for SMT mounting on the circuit board CB. The two electrical contacts SMC1 and SMC2 are electrically connected to the conductive winding arrangement CW starting from their respective opposite ends on the SMT mounting portion SM. For example, an electrical contact SMC1 can be electrically connected to these conductive winding arrangements CW near the SMT mounting portion SM, which resides on it via a conductive path. The CP contacts the conductive winding arrangement CW with the corresponding end from its arrangement on the SMT mounting portion and / or through the SMT mounting portion arrangement SM. The SMD coil 10V may also include a conductive element CV (conductive path or conductive rod or conductive wire), which passes through the SMT mounting portion SM connected to the second electrical contact SMC2 and reaches the far end of the coil portion C (away from the SMT mounting portion SM) where it is connected to the far end of the conductive winding arrangement CW. In an embodiment, the conductive element CV can be a conductive through-hole / rod or wire that passes through the magnetic core and is insulated from the conductive winding thereon. In such an embodiment, a conductive path can optionally be manufactured / arranged thereon. A conductive path can optionally be manufactured / provided on the distal end of the coil portion C to connect the conductive element CV to the distal end of the conductive winding arrangement CW. Alternatively, the conductive element CV can be delivered to the coil portion C from the outside to connect the second electrical contact SMC2 to the remote end conductive winding arrangement CW. Therefore, in this embodiment, the two SMT electrical contacts SMC1 and SMC2 electrically connected to the respective ends of the spiral winding are located on the outer surface of the SMT-mounting portion SM, which is substantially perpendicular to the flux axis FX (for example, at 90° or at least between 45° and 90° relative to the flux axis FX, depending on the SME configuration). The vertical spiral SMD coil 10V of this embodiment of the invention is therefore particularly suitable for surface mounting to a circuit board CB with its flux axis FX substantially perpendicular to the circuit surface, or at any other suitable angle, typically between 45° and 90°, relative to the circuit surface according to an optional SME configuration.

[0109] In addition to the above, combined with Figures 1A to 1CRelated to the above-described embodiments of the SMD coil 10, the following should be noted: Preferably, according to some specific implementations of the present invention, the conductive winding arrangement CW includes a spiral conductor arrangement directly on the magnetic core FC (e.g., with substantially no gap therebetween). Such a configuration may be achieved by embodiments of the SMD coil manufacturing methods 200 and 300 described below. An advantage of such a configuration, for example relative to conventional configurations (in which the core is inserted into the spiral after production, leaving a residual gap (e.g., an air gap)), is that the core occupies the entire geometric cross-section at the center of the spiral winding (without a gap), thereby resulting in a higher sensitivity of the coil (a higher induced voltage per magnetic field of a given strength for the same size and number of windings).

[0110] Typically, in a specific implementation of the present invention, the magnetic core FC of the SMD coil 10 has a tubular shape. In this regard, it should be noted that although Figures 1A to 1C In the specific non-limiting example of the examples of FIG. 1 , the magnetic core is shown as having a rectangular cross-section, but this cross-sectional shape is provided merely as an example, and generally any of the cross-sectional shapes described above may be implemented in the magnetic core of the SMD coil 10 without departing from the scope of the present invention.

[0111] Preferably, in some implementations of the SMD coil of the present invention, the ferrite core has an elongated tubular shape, thereby improving the effective magnetic permeability of the core and thus improving the induced voltage by the elongated magnetic core geometry. Alternatively, in some implementations where the geometric constraints of the device where the SMD coil prevents an elongated tubular core shape (e.g., in the case of providing a vertical SMD coil 10V in a conduit described below), the ferrite core can be formed to have a flat / squashed tubular shape and have a larger cross-section in order to compensate for the reduction in the effective magnetic permeability of the core due to its flat geometry.

[0112] Reference now Figure 2 , which is a flow chart showing a method 200 for manufacturing a spiral SMD coil directly on a magnetic core according to an embodiment of the present invention. More specifically, the method 200 facilitates manufacturing a spiral SMD coil directly on a peripheral surface of a magnetic core. Figures 1A to 1C The method 200 can be used to form a spiral conductive winding structure CW of the SMD coil 10 shown in FIG. 1 and can also be used to make appropriate conductive connections / paths CP between the conductive winding structure CW and the SMT contacts (SMC1 and / or SMC2) of the surface mount part SM. This is usually achieved by forming a pattern of the conductive winding on the magnetic core using a photolithography process and then electroplating the conductive winding along the pattern. More specifically, the method 200 includes the following operations as described below.

[0113] In operation 210, a magnetic core FC having a tubular shape as defined above is provided. Optionally, the magnetic core FC provided by embodiments of method 200 may include or consist of a sintered magnetic material having a magnetic relative permeability μ in the order of at least 100. Preferably, in some embodiments of the present invention, the magnetic core FC is essentially composed of the provided magnetic core FC, for example, there is no significant amount of non-magnetic material therein. Preferably, for some applications and in some embodiments of the present invention, a magnetic core of a material FC that is temperature stable in a temperature range of 20°C to 60°C (for example, having a temperature coefficient of magnetic permeability of less than 160 ppm / °C) is provided.

[0114] In optional operation 215, a seed layer may be fabricated on the circumferential surface / portion of the tubular magnetic core FC. This operation may be performed in the case where the exposed surface of the magnetic core FC is not conductive enough for electroplating. The seed layer may be fabricated by any suitable technique understood by those skilled in the art, such as by chemically applying a catalyst followed by applying a thin electroless copper coating on the circumferential surface / portion of the tubular magnetic core FC to increase its conductivity and facilitate subsequent electroplating. Operation 215 is optional, as the fabrication of a seed layer may not be necessary in the case where the exposed surface of the magnetic core is conductive enough for electroplating.

[0115] It should be noted that in various embodiments, operation 215 may be performed at different stages of method 200 .

[0116] For example, in some specific implementations of method 200, the catalyst is selectively deposited on the magnetic core FC and not on the photoresist applied thereon in operation 220 described below. In such embodiments, operation 215 may be performed only after operations 220 and 230 described below for making a seed layer at the surface of the core FC, from which the photoresist is removed by photolithography in operation 230. In such embodiments, the surface of the magnetic core beneath the photoresist will remain clean of both the catalyst layer and the seed layer, and the electroless copper will grow substantially only on the exposed surface of the magnetic core, whereupon the conductive winding will be formed by electroplating (operation 240). In such embodiments, the optional operation 245 of removing the remaining photoresist may be omitted, since no conductive layer is formed thereunder (note that actual removal of the photoresist may still be required, depending on the chemical and thermal stability of the photoresist used).

[0117] In some other example embodiments of method 200, where the catalyst used remains active after the photolithography process (UV light projection and photoresist developing solution) is applied, operation 215 may be performed in two stages:

[0118] - In a first stage, performed before operations 220 and 230, a catalyst may be applied to the magnetic core FC;

[0119] - In stage 2, performed after operations 220 and 230, a seed layer (helix and possible SMT flange) may be fabricated at the exposed core areas from which the photoresist pattern was removed.

[0120] In both implementations described above (where the seed layer itself is applied after photolithography of the photoresist and is not underneath it) and in embodiments where a seed layer is not required, removal of the remaining photoresist after patterning in optional operation 245 can be avoided because the conductive layer will not be formed underneath the photoresist. In practice, however, depending on the chemical and thermal stability of the photoresist used, the actual removal of the photoresist may still be performed in 245. Therefore, in some embodiments where removal of the remaining photoresist is not required, a permanent resist (similar to SU8, which can be used as a dry film photoresist) may be used in operation 230 below.

[0121] In yet another example implementation (e.g., which may be performed without promoting selective catalyst deposition and / or without the catalyst remaining active after the photolithography process), the deposition of the catalyst and seed layer in operation 215 may be applied to the core prior to applying the photoresist in operation 220. In this case, the conductive layer will be present under the photoresist, and operation 245 will be required after electroplating to strip the remaining photoresist and etch the seed layer between the conductive windings electroplated in operation 240.

[0122] In operation 220, a photoresist layer may be applied to the circumferential surface / cross section of the tubular magnetic core FC from all around (360°). Preferably, the photoresist layer is applied thick enough (e.g., at least 8 μm) to facilitate subsequent application of a relatively thick plating layer (e.g., at least 6 μm thick) in the area where the photoresist layer will be removed by patterning without causing the plated conductive material to overflow / diffuse outside the patterned area. This may advantageously enable subsequent fabrication of a relatively thick conductive winding of the coil having a low resistance.

[0123] In this regard, optionally, in operation 220, a dry photoresist layer may be used and may be applied to the entire circumference (360°) of the surface / segment of the tubular magnetic core FC. The use of a dry photoresist may be advantageous in this case because its application to the described 3D circumference of the tubular magnetic core FC may be more controllable and uniform (e.g., in thickness) than a wet photoresist, and because it facilitates achieving a substantially thick photoresist layer suitable for subsequent fabrication of conductive windings having low resistivity and defined boundaries by electroplating (i.e., this facilitates electroplating of narrow conductive wires of a spiral conductive winding having a substantial thickness while preventing spreading of the electroplating between adjacent wires and thereby facilitating small spacing therebetween and thereby fabricating a dense winding having a small pitch P).

[0124] Photolithography is applied to pattern the photoresist layer and form a spiral pattern on the circumferential surface / segment of the tubular magnetic core FC covered by the photoresist layer in operation 230. For example, the photolithography process may optionally include selective projection of photolithography light (e.g., UV light) of a suitable frequency, which on the one hand has sufficient power for patterning the photoresist, and on the other hand has insufficient power / intensity to cause damage to the underlying magnetic material of the core FC (so as not to damage the core and increase its conductivity).

[0125] The selective projection of the photolithographic light can be performed by direct scanning of the laser beam on the substrate. The circumferential surface / cross-section of the tubular magnetic core FC and / or by any other suitable technique that will be understood by a person skilled in the art of photolithography after understanding the present invention. It should be understood that, optionally, in order to apply the photolithographic pattern to the three-dimensional 3D circumferential surface / cross-section of the tubular magnetic core FC, the core can be rotated relative to the beam during projection, while also moving the core relative to the beam along the longitudinal axis FX of the core (for example, by moving the relative position of the core or by optically manipulating the beam). This can be done continuously or intermittently, depending on the shape of the cross-section of the core and the desired form of the spiral pattern to be produced. It should be noted that in embodiments of the present invention, the photoresist used can be a so-called "positive" photoresist or a "negative" photoresist, and the projected light pattern (as a negative pattern or a positive pattern) is adjusted accordingly to produce the desired spiral pattern of the exposed area of ​​the photoresist, where the conductive winding CW will subsequently be electroplated. As will be readily appreciated, exposure of the photoresist is followed by development of the photoresist to expose a spiral pattern on the circumferential surface / portion of the tubular magnetic core FC from which the photoresist is removed by said development.

[0126] Operation 240 includes electroplating the exposed areas of the magnetic core FC (the spiral pattern formed after the photoresist is developed) with a conductive material (e.g., Cu) to produce the conductive winding CW in the form of a conductive spiral coil on the outer surface layer of the magnetic core. Preferably, in some embodiments, the electroplating is performed to a thickness of the order of about 4 μm or more.

[0127] In optional operation 245, the remaining photoresist material may be removed from between the conductive windings of the spiral coil CW, which optional operation may be performed after the plating. In this regard, as indicated above, in some embodiments, the surface conductivity of the magnetic core FC below the remaining photoresist material may be above a minimum desired threshold (e.g., due to, for example, a seed layer, if it is manufactured in operation 215 before depositing the photoresist layer). In such embodiments, it may be desirable to reduce the surface conductivity of the magnetic core FC in order to prevent electrical shorts between adjacent windings (and also to inhibit the occurrence of eddy currents during operation of the coil). To achieve this, in operation 245, the remaining photoresist may be removed from the core, followed by etching of the conductive seed layer / material and / or catalyst that may have been located between the photoresist and the magnetic core. This operation may be performed, for example, in the case where it is necessary to remove the seed layer below the photoresist in order to clear a short across the spiral. Regarding the threshold, whether due to the catalyst, seed layer or the small intrinsic conductivity of the ferrite, the core resistance (whether due to volume or surface conductivity) must be greater than the coil (winding) resistance by a factor of about 100 or more. For example, considering that the resistance of a spiral winding from contact to contact is on the order of a few hundred ohms, the resistance of the ferrite / core, flange to flange (solder contact to solder contact) should be on the order of tens of kiloohms.

[0128] Finally, preferably, the spiral SMD coils or conductive winding portions thereof manufactured by method 200 may be coated with a thin layer of varnish or tin coating to prevent oxidation of the conductive windings (e.g., during storage of the coils prior to assembly of the coils in a sensor / circuit, at which time they may be further encapsulated with epoxy for protection).

[0129] In some embodiments of the present invention, a single winding layer may be fabricated directly on the magnetic core FC by method 200. This may reduce manufacturing complexity and cost while still providing adequate sensitivity due to the high density (small pitch) and high core permeability of the windings obtained by method 200. Alternatively, in some embodiments, stacked / concentric winding layers may be fabricated by repeating the relevant operations of method 200 while introducing insulating materials / layers between the fabrication of successive conductive layers, as will be appreciated by those skilled in the art.

[0130] In some embodiments of the present invention, method 200 can be suitable for manufacturing a conductive spiral coil CW with high-density windings, and wherein the pitch of the windings in the conductive winding structure CW is about or less than 10 μm (in some embodiments, preferably not more than about 8 μm). For example, the width of the conductive path of the windings forming the conductive spiral coil can be no more than 7 μm (in some embodiments, no more than 4 μm), and the spacing between the conductive paths of adjacent windings is about 4 to 5 μm, so as to provide a high-density winding on the ferrite core.

[0131] As described above in accordance with some embodiments of the present invention, the operations of method 200 may be performed so as to also make a suitable conductive connection / path CP between the conductive winding structure CW and the SMT contacts (SMC1 and / or SMC2) of the surface mounting portion SM of the SMD-coil 10 of the present invention. To this end, in operation 210 the ferrite core FC may be provided with a surface mounting portion SM. Therefore, optional operation 215 and operations 220 to 240 may be performed in sequence in a similar manner to that described above also to make a conductive connection / path CP between the conductive winding structure CW and the SMT contacts (SMC1 and / or SMC2) (multiple) surface mounting portions SM. For example, in an embodiment of a vertical SMD coil 10V, operations 220 to 240 may be performed to define two electrical contacts SMC1 and SMC2 on the same mounting portion SM without electrically short-circuiting them. Additionally, in some embodiments, wherein a vertically mounted SMD coil 10V is fabricated, the magnetic core FC may be provided with a through conductor CV passing therethrough generally along its longitudinal axis FX and one of the conductive paths CP may be fabricated with the through conductor CV incorporated as a part thereof, such as Figure 1C exemplified in the optional tags in .

[0132] Alternatively or additionally, in some embodiments, the method 200 can be mainly applicable to the manufacture of the coil part C and the SMD coil 10 and the connection between them, the surface mounting part SM and / or the conductive winding structure CW, and the coil part C and these SMT contacts (SMC1 and / or SMC2) on the surface mounting part SM can be carried out in separate processes.

[0133] Reference now Figure 3, which is a schematic diagram of an alignment system 280 according to an embodiment of the present invention. The manufacturing system 280 is configured and operable to implement at least the operation 230 of the above-described method 200 so as to apply photolithography on the magnetic / ferrite core FC to which the photoresist is applied, thereby forming a spiral photoresist pattern suitable for manufacturing (e.g., electroplating) a spiral conductive winding directly on the magnetic core FC. The manufacturing system 280 includes a lithography light source LS, such as a UV laser light source having the above exemplary properties, which is suitable for projecting light LL toward the magnetic core FC to apply lithography to the photoresist layer on the magnetic core FC. The manufacturing system also includes a processing tool HL, which is configured and operable to carry / hold the ferrite core and apply relative motion between the ferrite core and the light LL from the lithography light source LS to project (e.g., sequentially) a spiral winding pattern on the magnetic core FC. For example, a combination of a relative rotational motion RM around an axis RX and a linear motion LM parallel to the axis RX can be used to project a spiral pattern, which can be affected by a processor facility HL between the magnetic cores FC. Therefore, the processor module HL and the control device CU of the manufacturing system 280 suitable for controlling the processor module HL and the light source LS can be configured and operable to impose such relative movement between the magnetic core FC and the lithography beam LL so as to project a three-dimensional spiral pattern of lithography light onto the core.

[0134] Reference Figure 4 , wherein a flow chart of another method 300 for manufacturing a coil portion C of a compact SMD coil 10 according to an embodiment of the present invention is provided. More specifically, the method 300 is suitable for manufacturing a spiral coil directly on a magnetic core FC by winding a wire on the circumference of the magnetic core.

[0135] In operation 310 of method 300, a magnetic core FC having a tubular shape is provided. Optionally, in some embodiments, the magnetic core FC may include or consist of a sintered or more preferably fully sintered magnetic material having a magnetic permeability μ on the order of at least 100. In some embodiments, a magnetic core FC of a material that is temperature stable in a temperature range of 20° C. to 60° C. (e.g., having a temperature coefficient of magnetic permeability of less than 160 ppm / ° C.) is provided.

[0136] Optionally, in Figure 1C In a specific implementation of the vertical mounting configuration of the SMD coil 10 shown, the magnetic core FC may be provided with a through conductor CV extending from a first end of the magnetic core through the magnetic core (typically along its longitudinal axis FX) to an opposite end for conductively connecting a surface mount connection SMC of a surface mount portion SM located at said opposite end to an end of a spiral coil / conductive winding CW proximate to said first end (this is optional, as an external conductor may alternatively be used for this purpose without substantially impairing the functionality of the coil).

[0137] Note that sintered magnetic cores are generally relatively brittle and may be relatively easily damaged under the pressure / tension applied thereto during the winding process. Therefore, in some embodiments, optionally to facilitate the mechanical durability of the magnetic core during winding, the provided magnetic core may have a circular cross-section in the wound center portion (so as to relieve stress from the wound wire), while the flange area may have a polygonal / rectangular cross-section, so that the magnetic core can withstand the stress applied thereto by the wire during its winding without substantial damage.

[0138] Alternatively or additionally, as shown in optional operation 320, in some embodiments, before the wire is wound, one or more surface areas of the magnetic core are coated / attached with a buffer layer / structure, the material of which is suitable for releasing mechanical stress from the magnetic core itself and / or from the wire wound thereon. For example, a flexible material layer such as wax can absorb / mitigate / distribute some of the stress applied between the magnetic core and the thin wire during winding (thereby preventing damage to the core and breakage of the wire during winding), or a structurally reinforced material such as a polymer, such as coating the surface of the magnetic core, or being provided as a "post" at the corner of the magnetic core (in the case where its cross-section is polygonal) to absorb / distribute some of the stress applied between the magnetic core and the thin wire. In some embodiments, it is not necessary to remove the buffer layer or structure after the winding process (e.g., so as not to potentially form any gap between the winding and the core). Alternatively, in, in other embodiments, the material may be removable / removable from the core after winding.

[0139] In operation 330, a thin wire (e.g., having a characteristic width of about 10 μm and less than 20 μm) is provided and wound around the magnetic core to form the conductive winding structure. The winding can be implemented with one or more layers of wound wire to form a single helix structure or a plurality of concentric helix structures on the circumference of the magnetic core.

[0140] Typically, the winding of the horizontal spiral SMD coil 10H is performed with an odd number of winding layers, so that the two ends of the wound wire fall on the opposite ends of the magnetic core to connect to the metallization / contact areas there. Therefore, typically, the winding of the vertical spiral SMD coil 10V is performed with an even number of layers, so that the two ends of the wire fall on the bottom surface of the magnetic core (the core will be mounted on the circuit board). In this case, each end of the wire is attached to a different metallized contact pad on the SMT base of the bottom core (no need to pass the wire through a drill bit of the ferrite core or reach the coil from the outside).

[0141] Preferably, the winding is performed while relieving the tension applied to the wound wire to prevent the wire from tearing (for example, when a wire with a wire diameter of 10 μm is used, the maximum tension applied to the wire during the winding process does not exceed about 1.4 g.

[0142] Thus, the embodiment of the method 300 is suitable for manufacturing the coil portion C of the SMD-coil 10 of the present invention. In this regard it should be noted that the method 300 as described above is particularly suitable for manufacturing conductive windings using thin wires of a characteristic diameter / width. While alleviating the pressure / stress exerted by the wire on the magnetic core and alleviating the tension from the wire, to eliminate or at least reduce and control any damage to the magnetic core affected by the wire winding process, and also to prevent / reduce tearing of the wound wire during the process. For example, a 10μm diameter copper wire (e.g., 12-13μm, including enameled wire insulation), or even thinner wire, can be directly wound on the magnetic core in one or more layers, for example, with hundreds of turns (e.g., 600).

[0143] Therefore, considering that the above method 300 can achieve high manufacturing yields of high density direct winding of thin wires on magnetic cores, while reducing the generation of waste / damaged products. In some implementations, the method 300 can also be implemented for automatic / fully automatic production of compact coils. Therefore, a robust method for manufacturing SMD coils with robust SMT contacts (which is more reliable than soldering wires) is provided.

[0144] The above-described methods 200 and 300 are typically supplemented by attaching / providing one or more surface mounting parts SM from one or both ends of the magnetic core FC and electrically connecting their contacts to the coil. In order to avoid interference of the mounting parts SM with the operation of the coil C, the surface mounting parts SM may be formed of a non-ferromagnetic material (e.g., copper and / or tin) and / or may be formed of nickel, which, although ferromagnetic, may be used in some cases depending on the specific design of the magnetic core and the nickel coating used. In various embodiments, the attachment of the surface mounting parts SM may be performed prior to the implementation of the method 200 or 300 for manufacturing the conductive winding structure CW of the coil part C. Alternatively or additionally, in the case of the implementation of the method 200, the attachment of the surface mounting parts SM and / or their electrical connections to the coil may also be performed during or after the implementation of the method.

[0145] Now let’s refer to Figures 5A to 5D, 6A to 6D, 7A to 7D and 8A to 8D, show several embodiments of a position sensor 100 according to the present invention, which is suitable for measuring a signal indicating at least one of the position and orientation of the sensor relative to a magnetic field source. The position sensor 100 in each of these embodiments includes a flexible circuit board CB, for example, a foil circuit board or a flexible PCB suitable for use with the sensor of the present invention or any other suitable flexible circuit surface for use with any inventive sensor), and at least three spiral SMD coils surface mounted to the circuit board CB using surface mounting technology (SMT). The flexible circuit board CB is folded into an operating configuration in which the at least three spiral SMD coils are arranged so that their magnetic axes FXs are not arranged coplanarly, so that the at least three spiral SMD coils can sense different aspects of a given external magnetic field, which different aspects indicate at least one of the position and orientation of the sensor 100 relative to the external magnetic field (i.e., relative to the external magnetic field source). Therefore, the signals obtained from the at least three SMD coils are used to measure / evaluate at least one of the orientation and position of the sensor 100 relative to one or more magnetic field sources.

[0146] For brevity Figures 5A to 5D , 6A to 6D, 7A to 7D and 8A to 8D, various embodiments of the sensor 100 of the present invention are depicted in a self-explanatory manner as follows: Figure numbered Figure #A (i.e. Figures 5A to 8A ) provides a schematic perspective view illustration showing corresponding flat / planar circuit layouts of position sensors 100 according to several embodiments of the present invention, wherein a corresponding arrangement of SMD coils 10 is shown as surface mounted to a flexible circuit CB (in Figures 5A to 8A FIG. 1 shows a perspective view of the circuit layout when the surface of the flexible circuit CB is flat, that is, before the flexible circuit CB is folded / rolled up to produce the operating configuration of the sensor); FIG. #B (i.e. FIG. 5B to FIG. 8B Provides the corresponding FIG. 5A to FIG. 8A Schematic side view illustration of the position sensor 100 of the corresponding embodiment of the sensor shown in FIG. #C (ie Figures 5C to 8C ) and the figure numbered Fig.#D (i.e. Figures 5D to 8D ) is a schematic front view showing a cross-section of the position sensor circuit viewed along the longitudinal axis of the position sensor circuit after the flexible circuit CB is folded / rolled about corresponding folding axes FAi and FAo to form the operating configuration of the sensor 100, whereby the figure numbered Fig. #C illustrates an embodiment in which the flexible circuit CB is folded so that the coil is located at the outer surface of the folded flexible circuit CB, and the figure numbered Fig. #D illustrates an embodiment in which the flexible circuit CB is folded so that the coil is located at the inner surface of the folded flexible circuit CB.

[0147] At this point Figures 5A to 8D Two optional folding axes FAi and FAo are illustrated, about which the circuit board CB can be folded so that it forms a tubular structure. Figure 5C , Figure 6C , Figure 7C and Figure 8C As shown, the circuit board CB can be folded around the folding axis FAo into a tubular structure (open or closed), and the sensor coil 10 is arranged on the outer surface of the tubular structure of the folded circuit board CB. In such an embodiment, for example, the circuit board CB can be folded / -rolled into a tube with an inner diameter of less than 1 mm, preferably even less than 1 mm. Size: 0.9 mm In this case, the circuit board CB can be, for example, a foil circuit with a thickness of about 10 to 50 microns (for example, a foil with a thickness of 10 to 50 microns). 0.0127mm) with printed conductive tracks / connection CC-pads, on which the SMD coil of the sensor can be mounted and soldered). In some embodiments, such as for example Figure 5D , 6D , 7D and 8D, the circuit board CB can be folded into a tubular structure (open or closed) around a folding axis FAi, so that the sensor coil 10 is arranged on the inner surface of the tubular structure of the folded circuit board CB. For the sake of clarity, hereinafter, the folding axis FAi or FAo around which the circuit board CB is folded is also considered and referred to as the longitudinal axis of the sensor 100.

[0148] For simplicity, in Figures 5A to 8D In the non-limiting example of the position sensor 100 provided in , at least three spiral SMD coils are shown as being arranged at angular intervals of 60° or 120° relative to a specified folding axis as FAo or FAi. However, it should be understood that these angular intervals are provided herein only as examples, and in various embodiments of the present invention, the at least three coils may be arranged to have other angular intervals between them (e.g., possibly with 90° intervals, and / or with different / varying angular intervals between them, while still being operable to sense the position and / or orientation of the sensor relative to one or more magnetic field sources. In this regard, it should be understood that the sensor 100 may generally be configured to have angular intervals of the coils different from those shown in the figures, in order to, for example, accommodate various design constraints, such as a compact / desired arrangement of the coils 10 and / or to reduce / adjust mutual sensing of common magnetic field signal components by different coils.

[0149] Now refer to Figures 5A to 5D The exemplary embodiment of the position sensor 100 shown in FIG. 1 is adapted to measure a position indicating its relative position to a magnetic field source MF. OIn this embodiment, at least three SMD coils 10 may, for example, include a plurality of SMD coils 10 as described above. Figure 1B The described embodiment of the present invention is configured with three horizontal spiral SMD coils 10H. To this end, the three SMD coils 10H can be surface mounted on the surface of the circuit board CB by surface mounting technology.

[0150] In various embodiments, the position sensor 100 or Figures 5A to 5D The FAi or FAo sensor 100 is specifically designed to facilitate the determination of the orientation of the longitudinal axis using the signals obtained from the three SMD coils. O The magnetic field source MF O Usually located in front of the sensor. 100 along the general direction of the longitudinal axis FAi or FAo The signals obtained by the sensor 100 from the three SMD coils 10H facilitate the determination of the relative magnetic field source MF O Orientation about two angles (i.e., pitch and yaw) about the longitudinal axis of the sensor 100. In order to achieve this accurately, the three SMD coils 10H can be provided on the circuit board CB with parallel orientation of their flux axes FXs relative to the surface of the circuit board CB and such that their flux axes FXs are substantially parallel to each other. Preferably, to facilitate accurate orientation measurement, the three SMD coils 10H are arranged on the circuit board CB such that they (particularly their core portions) C are lit / adjusted relative to the straight guide line GL perpendicular to the longitudinal / folding axis FAi or FAo and such that their flux axes FXs are substantially parallel to the longitudinal / folding axis FAi or FAo. Therefore, when the circuit board CB is bent / folded about the folding axis FAi or FAo to its designated operating configuration, the flux axes FXs of the three SMD coils 10H are substantially parallel to each other while not being coplanar (to facilitate orientation measurement about two angles), and preferably all three SMD coils 10H (particularly their core portions C) are aligned relative to a common reference plane RP (the reference plane can be, for example, a plane accommodating the guide GL when the circuit is folded). Preferably, in some embodiments, Figures 5A to 5D The embodiment of the invention is used to measure the relative magnetic source MF O The at least three spiral SMD coils 10H of the orientation are coils having similar configurations (sizes and inductance / reactance values).

[0151] therefore, FIG. 5A to FIG. 5D The position sensor 100 is suitable for being configured to accurately measure the position of the sensor relative to a magnetic field source MF. Ooriented, the magnetic field source is generally positioned in front of the three spiral SMD coils 10H of the sensor. Thus, by taking into account the voltage induced by each SMD coil 10H, a signal processing circuit (not specifically shown); for example, a computerized system connectable to the sensor is operable to determine the magnetic field source MF O For example, a compact spiral SMD coil 10H configured in accordance with the present invention has a longitudinal dimension of the core C extending about 1.2-1.4 mm (a total of about 2 mm with the surface mounting portion), and a transverse dimension (width / diameter) extending about 0.6 mm or less and more preferably about 0.5 mm, and can produce a sensitivity of about 0.2 μV / (Gauss*Hz), thereby enabling accurate measurement of the magnetic field relative to the source MF. O Orientation. A person skilled in the art will readily understand that Figures 5A to 5D The SMD coil 10H of the sensor 100 obtains the signal to determine / evaluate the magnetic field source MF O Various techniques relative to its orientation.

[0152] Now refer to Figures 6A to 6D The exemplary embodiment of the position sensor 100 shown in FIG. 1 is adapted to measure a position indicating its relative position to a magnetic field source MF. L In this embodiment, the sensor 100 comprises a flexible circuit board CB and three SMD coils, whereby: at least two of the three SMD coils 10 are based on Figure 1C A vertical spiral SMD coil 10V is surface mounted on the surface of the circuit board CB via surface mounting technology with its magnetic flux axis FX vertically / perpendicularly oriented relative to the circuit board CB, and one of the at least three SMD coils 10 is according to Figure 1B The horizontal spiral SMD coil 10H is configured and surface mounted to the surface CB of the circuit board via surface mounting technology with its magnetic flux axis FX in a horizontal orientation relative to the circuit board CB. The three SMD coils 10 are arranged on the printed circuit board CB so that when the printed circuit board CB is bent / folded / rolled up around the folding axis FAi or FAo to its designated operating configuration (such as Figures 6B to 6D), the flux axes FXs of the three SMD coils 10 are not parallel to each other and span three-dimensional coordinates, which enables the coils to measure different vector components in the magnetic field near them. More specifically, for example, two vertical spiral SMD coils 10V can be arranged so that when CB is bent to its operating state, the flux axes of the two SMD coils are not parallel and are, for example, 90° or 120° relative to each other, and the horizontal spiral SMD coil 10H can, for example, be arranged so that its flux axis is relatively parallel to the folding axis FAi or FAo of the circuit board (for example, optionally in some specific implementations, this can promote compact folding of the circuit board).

[0153] To this end, the arrangement of at least three SMD coils 10 having a flux axis FX spanning a three-dimensional coordinate facilitates the measurement of the vector components of the magnetic field in their vicinity, thereby enabling the determination of the relative position of the sensor 100 to the magnetic field MF. L The position and / or orientation of an external source. Typically, for example, by using a magnetic field MF L An external source generates multiple distinguishable magnetic fields (e.g., typically at least three magnetic fields of different frequencies), and both the position and orientation of the sensor 100 can be determined. A person of ordinary skill in the art will readily appreciate various techniques by which the magnetic field source MF can be determined based on measurements of the magnetic field vector components at the sensor 100. L Relative position and / or orientation of sensor 100 .

[0154] Preferably, in some embodiments, Figures 6A to 6D The two vertical spiral SMD coils 10V used in the embodiments of the present invention can be similarly configured coils (size and inductance / reactance values). In some embodiments, the vertical spiral SMD coil 10V is configured to have a core cross-section that is elongated in one lateral dimension (such as a core with an elliptical cross-section or a rectangular cross-section, where Fig. 6A , one lateral dimension is greater than the other) and are arranged vertically on the circuit board CB so that the longer sides of their core cross-sections are substantially collinear with the folding axis FAi or FAo about which the circuit board CB is to be bent. This has the advantage of giving these coils a sufficiently large cross-section in order to produce the desired sensitivity of the position sensor, while on the other hand enabling compact folding of the circuit board CB and thus of the sensor in compact dimensions, since only the short lateral dimension of the core is perpendicular to the folding axis and the larger lateral dimension is aligned with the folding axis, and this does not limit the diameter of the circuit board folding. Therefore, Figures 6A to 6D The position sensor 100 is suitable for being configured to accurately measure the position of the sensor relative to a magnetic field source MF. LFor example, an SMD coil 10V configured with a compact configuration according to the present invention and having a longitudinal dimension extending along its magnetic axis of about 0.45 mm to 0.6 mm (typically about 0.5 mm or less) and having an elongated / elliptical cross-section with a transverse dimension of about 0.7 mm×2.2 mm can produce a sensitivity of about 0.1 to 0.2 μV / (Gauss*Hz) for sensing magnetic fields in the kHz frequency range, thereby enabling accurate measurement of the magnetic field source MF L Note that the sensitivity measurements are shown here for a uniform magnetic field and that the sensitivity for an inhomogeneous field may be smaller).

[0155] Now let’s refer to Figures 7A to 7D 8A to 8D. In these examples, the position sensor 100 includes at least five SMD coils 10, which are surface mounted on one or more flexible circuit boards CB (only one circuit board is shown in the non-limiting example shown in the figure). Three of the at least five SMD coils 10 of the sensor 100 can be horizontal spiral SMD coils 10H, which can be configured and arranged in the same manner as described above with respect to FIG. 5A to FIG. 5D The sensor 100 may be arranged on the circuit board CB in a manner similar to that described above (e.g., such that when the circuit board CB is provided at the sensor in its folded / rolled-up operating state, their magnetic flux axes FX are parallel to each other and not coplanar). In addition, two of the at least five SMD coils 10 of the sensor 100 may be vertical spiral SMD coils 10V, which may be arranged in the same manner as described above with respect to Figures 6A to 6D The vertical spiral SMD coils 10V described are configured and arranged in a similar manner on the circuit board CB (e.g., such that when the circuit board CB is provided at the sensor in its folded / rolled-up operating state, their magnetic flux axes are not parallel to each other, e.g., at 90° or 120° relative to each other, and are also not parallel to the magnetic flux axes FX of the three horizontal spiral SMD coils 10H of the sensor 100). This configuration thus makes it possible to determine the position of the sensor 100 relative to the first magnetic field source MF using the signals obtained from the three horizontal SMD coils 10H. O The sensor 100 is used to determine the orientation angles (e.g., pitch and yaw) of the second magnetic field source MF using the signals obtained from the two vertical spiral SMD coils 10V together with the signals obtained from any one (or more) of the horizontal SMD coils 10H. L orientation and / or position (e.g., which is operable to generate a magnetic field having a second frequency such as between 1 kHz and 4 kHz), the first magnetic field source can be positioned in front of the three horizontal spiral SMD coils 10H along the approximate direction of their flux axes and operated to generate a magnetic field having a first frequency such as 16 kHz.

[0156] As in Figures 7A to 7D 8A to 8D, at least five SMD coils 10 can be arranged in various arrangements on one or more circuit boards CB of the sensor while satisfying the above configuration, so as to adapt to different prerequisite compact sizes of the sensor while encapsulating high sensitivity coils therein. Figures 7A to 7D In the illustrated embodiment, a particularly narrow tubular-shaped sensor 100 is configured to encapsulate the five SMD coils 10. In this example, three horizontal spiral SMD coils 10H are arranged in a first row of the sensor 100, for example, aligned with the guide line GL, and two vertical spiral SMD coils 10V may not be arranged in the same row (for example, may be arranged on one or more circuit boards CB backward from the row of three horizontal spiral SMD coils 10H), so that the circumference of the circuit board CB needs to accommodate the three horizontal spiral SMD coils 10H at one circumferential area and the two vertical spiral SMD coils 10V at a separate circumferential area. Therefore, in this case, as Figure 7C and 7D As shown, in the folded state of the circuit substrate CB, the cross-section of the three horizontal spiral SMD coils 10H can overlap the cross-section of the two vertical spiral SMD coils 10V, which thus allows compact folding of the circuit substrate CB. Therefore, a particularly narrow configuration of the sensor can be provided in this case. For example, in some embodiments, the circuit board CB can have a thickness of about 12-15 μm, and have a longitudinal dimension of about L≈10 mm and a width of about W≈2.5-3 mm, and can be rolled into a tubular shape with a diameter of about 1 mm or less.

[0157] Alternatively, for example, in Figures 8A to 8D In the embodiment shown, a particularly short longitudinal dimension of the sensor 100 can be obtained. In this example, all SMD coils 10 are usually arranged in a single row on the circuit board, so that a short dimension of the sensor is obtained, such as for example Figure 8B shown.

[0158] Reference Figures 5A to 8D In the sensor 100 shown in FIG. 1 , the following should be noted:

[0159] In an embodiment, for example, for determining relative to the first magnetic field source MF O The orientation of the three coils 10H can be similar coils or rectangular circular or elliptical cross-section, and can be used with one of the three coils to determine the relative magnetic field source MF of the second LThe orientation / position of the two additional coils 10V may be similar or different and may typically have an elongated cross-section (e.g., elongated along the longitudinal axis of the sensor), such as an elongated rectangular cross-section or an elliptical cross-section. It should be understood that although all coils 10 of the sensor 100 in the above examples are considered to be surface mountable coils (e.g., according to Figures 1A to 1C ), but in other specific implementations of the sensor 100 contemplated by the inventors, some coils may not be SMD coils and / or may not be based on Figures 1A to 1C For example, in an embodiment, for determining the relative magnetic field source MF O The three coils of the orientation may be SMD coils configured according to the invention and used to determine the orientation relative to the second magnetic field source MF L The two additional coils in the position / orientation of may alternatively be other types of coils, such as air-core coils.

[0160] To this end, it should be understood that the sensor 100 can be connected to a signal processing circuit (not specifically shown), which can include, for example, external analog and / or digital processing circuits suitable for processing the signal of the SMD coil 10 to determine the sensor relative to the magnetic field source MF. O The orientation of the sensor and / or relative to the second magnetic field source MF L position / orientation.

[0161] Reference now Fig. 9A , which shows a block diagram of a medical device 1000 according to an embodiment of the present invention. The medical device 1000 may be a compact invasive medical device, generally comprising a housing H and a magnetic field-based position sensor 100 constructed according to the present invention and fixedly disposed at the housing H. The medical device 1000 is also associated with at least one magnetic field source MF, which is configured and operable to generate a specified magnetic field around it so that the magnetic field-based position sensor 100 can determine at least one of its position and orientation relative to the at least one magnetic field source MF. It should be noted that in various embodiments, the at least one magnetic field source MF may or may not be enclosed in the housing H and may or may not be an integral part of the medical device 1000. As will be understood from the following description, in some embodiments, the medical device 1000 is associated with several at least one magnetic field source MF that generates magnetic fields of different properties (e.g., different frequencies) so as to enable the relative position of the orientation of different parts of the medical device 1000 to be measured. According to the present invention, the magnetic field-based position sensor 100 is based on, for example, FIG. 5A to FIG. 8DThe present invention is configured as described in any of the embodiments of the present invention and comprises one or more SMD coils 10 (typically multiple) mounted on a flexible circuit board CB, which is arranged in the housing in its operating configuration, in which it is bent / folded / rolled up as described above, so that the magnetic flux axes of the one or more SMD coils 10 are not coplanar. Therefore, in this configuration, a highly sensitive and compact position sensor 100 is contained within the small size of the medical device.

[0162] Reference now Fig. 9B , which schematically shows a perspective view of a medical device 1000 according to an embodiment of the present invention. The medical device 1000 of this specific implementation illustrates the above Fig. 9A The structure of the medical device shown in the figure is that the housing / medical device has a main body M having a long axis L, and a front end T flexibly connected to the front end of the main body M via a belt-shaped coupler J such as a spring or a joint, and is configured so that the direction of the front end T can be bent relative to the long axis L of the housing when a force F corresponding to the magnitude and direction of the applied force F is applied (for example, applied when the front end T of the medical device is in contact with the patient's body tissue). In this example, the medical device 1000 includes a magnetic field source MF O , which may be, for example, a coil associated with a suitable circuit for generating a magnetic field. O Typically fixedly located at the end section T and based on magnetic field, the position sensor 100 is typically located within the main section M of the housing (note that in some embodiments, the magnetic field source MF O The opposite configuration where the position sensor 100 may be located at the main section and at the tip may be implemented depending on the design / dimensional constraints of the medical device.) Magnetic field source MF O The magnetic field-based position sensor 100 is configured and operable to generate a magnetic field that provides a reference frame indicating the orientation and possibly the position of the housing segment (hereinafter and without loss of generality, the end segment T) with which it is equipped. O In another main body part (hereinafter and without loss of generality referred to as the main part M) whose part is movable (e.g., rotatable) (e.g., relative to the end part T), the magnetic field-based position sensor is configured and operable to sense the magnetic field source MF. O The generated magnetic field and based on the measurements determine / estimate the orientation of the tip portion T relative to the main portion M, which orientation is generally indicative of a force vector F applied to the tip portion (eg, between the tip and body tissue when the medical device is used in a medical procedure).

[0163] For this purpose, the magnetic field source MF OIt can be, for example, a coil arranged in the end section T and generating, for example, an alternating magnetic field with a frequency in the kHz range (e.g., 16 kHz). For example, in an embodiment, for example, the magnetic field source MF O The coils of can be arranged such that in a neutral unbent position of the end section T relative to the longitudinal axis L of the housing, their magnetic flux axes are substantially collinear / coincident with the longitudinal axis L of the housing. The magnetic field based position sensor 100 is a position sensor 100 configured according to the present invention, for example in Figures 5A to 5D , 7A to 7D and 8A to 8D, wherein at least three SMD coils are arranged so that their magnetic field axes are substantially parallel and not coplanar. Figures 5A to 5D As described, this enables the sensor 100 to be measured relative to the magnetic field source MF O The orientation of the sensor is approximately to the orientation angle (e.g., pitch and yaw) while utilizing a highly sensitive, compact and reliable SMD coil 10 for this purpose. In this example, as shown, three horizontal spiral SMD coils 10H are arranged in the sensor on a folded / rolled flexible circuit board CB, of which only two are visible in the figure 100, to provide a compact, sensitive and reliable sensor configuration.

[0164] To this end, considering the technology of the present invention, a person skilled in the art will readily understand how to O The measurement result of the magnetic field generated is used to determine the relative position of the sensor 100 to the magnetic field source MF. O The orientation of (which provides a reference frame relative to which the orientation can be determined). In addition, a person skilled in the art will readily understand how the force vector F can be determined based on the measured orientation and the (e.g., spring constant) of the ribbon coupler J.

[0165] Reference now Fig. 9C , which schematically shows a side view of a medical device 1000 according to another embodiment of the present invention. The medical device 1000 in this embodiment combines the features of the medical device 1000, referring to Fig. 9B The medical device 1000 is adapted to determine the orientation of the tip segment relative to its main segment (e.g., or to determine the force exerted on the tip), and is also adapted to determine / measure the spatial position and / or orientation of the medical device 1000 itself. For this purpose, the medical device 1000 comprises a magnetic field-based position sensor 100 according to the invention, which comprises at least five coils and is associated with another magnetic field source. L It is located outside the medical device. 1000 and is configured and operated to generate a second magnetic field, which is different from the magnetic field generated by the magnetic field source MF OIt provides a spatial reference system, the position and / or orientation of the medical device relative to the spatial reference system. 1000 can determine (eg the source of the magnetic field can be determined) MF L The MF may be adapted to generate the magnetic field at two or more frequencies different from the frequency of the magnetic field source. O This enables the position and orientation of the medical device to be determined. 1000 The medical device 1000 in this embodiment may include the position sensor 100 of the present invention, such as in Figures 7A to 7D The position sensor shown in any one of the embodiments of 8A to 8D includes at least five coils / SMD coils. Therefore, as described above with reference to these figures, a subset of at least three coils of the at least five coils can be arranged so that their magnetic flux axes span three-dimensional coordinates, thereby enabling the medical device 1000 to measure the magnetic field relative to the source MF. L To determine the spatial position and / or orientation of the medical device 1000 (as indicated above, both the position and orientation can be determined). In this example, as shown in the figure, three horizontal spiral SMD coils 10H of the present invention, only two of which are visible in the figure, and two vertical spiral SMD coils 10V of the present invention (only one of which is visible in the figure) are arranged in the sensor 100 above the folded / rolled flexible circuit board CB to provide a compact sensitive and reliable sensor configuration.

[0166] Reference now Fig. 10A and Fig. 10B . Fig. 10A The method 400 of the magnetic position sensor 100 Fig. 10A The present invention includes the following aspects:

[0167] 410-Providing a flexible circuit board (FCB);

[0168] 420-providing at least three surface mounted coil devices (SMD coils);

[0169] 430- Mounting at least three SMD coils on the FCB by surface mounting technology; and

[0170] 440-Folding / winding the FCB having at least three SMD coils mounted thereon into a tubular form, whereby the folding is performed so that the magnetic axes of the at least three SMD coils are not coplanar, thereby providing a magnetic field sensed by the at least three SMD coils from one or more magnetic field sources so as to enable measurement of at least one of the position and orientation of the sensor relative to the magnetic field source.

[0171] More specifically, in operation 410, a flexible circuit board (FCB) is provided for mounting the coils of the magnetic position sensor thereon. The use of a flexible circuit board (FCB) is advantageous over other techniques for connecting the coils, such as direct wiring, because it facilitates robust and accurate containment of the coils at the proper location and orientation on the sensor (e.g., in the medical device in which it resides), while also facilitating compact arrangement of the coils in a cost-effective manner. In operations 420 and 430, at least three surface mount coil devices (SMD coils) are provided and mounted on the FCB using surface mount technology that facilitates precise, compact, and reliable / robust electrical and mechanical connection of the coils to the FCB. Then, in operation 440, the FCB is folded (e.g., rolled) into a tubular form having appropriate dimensions so that it can be fitted into the required miniaturization of the sensor. For example, as described above, in various embodiments of the present technology, the magnetic position sensor will be fitted within a medical device, such as a catheter having an elongated body / housing with a tubular shape having a characteristic diameter of approximately 2 mm. Thus, the FCB can be folded / rolled into a tubular / cylindrical form having a smaller diameter that can be fitted within such a medical device.

[0172] As indicated above in various embodiments, the FCB may be folded / rolled such that the SMD coils mounted thereon face inwardly and / or outwardly relative to the folding axis. The SMD coils are arranged on the FCB such that when the FCB is folded / rolled about a certain designated folding axis, the magnetic axes of the SMD coils are not coplanar relative to each other, thereby facilitating measurement of at least one of the position and orientation of the sensor relative to one or more magnetic field sources. For example, in the above Figures 5A to 8C Several non-limiting examples of mounting arrangements of SMD coils on FCBs and folding of the FCBs therewith are shown in FIG.

[0173] In some embodiments, as indicated above, the magnetic positioning sensor may be adapted to measure a signal indicative of the orientation of the sensor relative to a magnetic field source (e.g., reference MFo in the figures described above). In such embodiments, the mounting operation 430 may include mounting three of the SMD coils on the FCB such that when the FCB is folded into a tubular form, their magnetic flux axes are parallel to each other and not coplanar, such that when the magnetic field source MF O When positioned in front of three SMD coils relative to the general direction of their flux axes, two orientation angles relative to the magnetic field source can be measured.

[0174] Alternatively or additionally, as also described above, the magnetic position sensor 10 may be adapted to measure a magnetic field indicating the position of the sensor relative to one or more external magnetic field sources (e.g., reference MF in the above figures). L) signals of the position and orientation of the sensor 100. In such embodiments, the mounting operation 430 may include mounting three of the SMD coils so that when the FCB is folded into a tubular form, their magnetic flux axes span the 3D coordinates and thereby enable measurement of the position and orientation of the sensor 100 relative to these one or more external magnetic field sources MF L position and orientation.

[0175] Alternatively or additionally, in e.g. Fig. 9C In some implementations illustrated in FIG. 1 , the magnetic positioning sensor is adapted to measure a signal indicating the orientation of the sensor relative to a first magnetic field source MFo and a signal indicating the orientation of the sensor relative to one or more second external magnetic field sources MF L The at least three SMD coils provided in 420 in such an embodiment include at least five SMD coils. The installation in 430 in such an embodiment is performed such that: a first subset of at least three of the SMD coils are arranged such that their magnetic axes are parallel to each other, and such that after the FCB is folded they remain parallel but not coplanar (to facilitate orientation measurement relative to the first magnetic field source MFo, as indicated above); a second subset of at least three of the SMD coils are arranged such that their magnetic flux axes span the 3D coordinates after folding of the FCB (operation 440) to facilitate orientation measurement relative to one or more second magnetic field sources MF L The position and orientation of Figures 7A to 8C An example of such an arrangement of coils is shown in FIG. As described above, mounting (operation 440)) may be performed using surface mounting techniques and may include mounting one or more SMD coils 10V with their flux axes oriented vertically relative to the FCB surface and / or mounting one or more SMD coils 10H with their flux axes oriented horizontally / parallel relative to the FCB surface.

[0176] In some embodiments, in operation 440, the FCB with the SMD coil mounted thereon is folded / rolled into a tubular form having a sufficiently narrow outer diameter Do so that it can fit within a small / narrow medical device. For example, in some implementations, the outer diameter Do of the sensor Do should not exceed about 2 mm after the FCB has been folded / rolled. Thus, as in, for example, Fig. 10B As schematically shown in FIG. 1 , in some embodiments, the tube T can be used to assist in the proper folding of the FCB. The tube T can be used as an internal skeleton, such as Fig. 10B As illustrated, the FCB is folded around the inner frame, or as an outer frame, the folded FCB can be inserted into the outer frame. The tube T can be, for example, a polyimide tube. Fig. 10BIn the example shown, the tube serves as an inner tube around which the FCB is folded and has a characteristic diameter Di of about 0.92 mm. The FCB is folded thereon to form an outer tube of diameter Do of 1.97 mm so that it can fit within a narrow medical device, and the SMD coil thus resides in the spacing between the inner and outer diameters (about 0.53 mm) as shown in the figure. In some implementations, the folding 440 also includes encapsulating (encapsulating) the electronic components of the sensor 100 (FCB, SMD coil, etc.) together with any welded cable wires connected thereto so as to form the sensor as a solid, single-piece unit. Sensor encapsulation can be performed using, for example, UV or thermal adhesives, and can be performed in a single-stage process or a two-stage process (e.g., blocking one end with adhesive and then filling from the other end). Preferably, during potting, the empty space between the polyimide tube T and the rolled thin FCB with the coil and any welded cable wires connected thereto is filled with adhesive. The potting preferably also anchors any welding cable wires connected to the FCB / coil cable so as to protect them from mechanical stresses that may be applied thereto during insertion of the medical device.

[0177] It should be noted that in some embodiments, operation 420 of method 400 includes utilizing, for example, Figure 2 or Figure 3 The method of the present invention as described above manufactures one or more SMD coils. For example, in some embodiments, using Figure 2 A photolithographic coil manufacturing technique is described in order to form one or more spiral coils of a SMD coil therewith directly on a ferrite core.

Claims

1. A position sensor adapted to measure a signal indicative of at least one of a position and an orientation of the sensor, the position sensor comprising: i. Circuit board; and ii. at least three coils located on the circuit board and arranged to sense different aspects of an external magnetic field, the different aspects indicating at least one of a position and an orientation of the sensor relative to one or more magnetic field sources; Features: The circuit board is a flexible circuit board (FCB), and the at least three coils are at least three surface mounted coil devices (SMD coils) mounted on the FCB via surface mount technology (SMT); and The FCB is arranged at the sensor in a folded / rolled state so that the magnetic flux axes of at least three of the SMD coils mounted on its surface are not coplanar, thereby being able to measure at least one of the orientation and position of the sensor relative to one or more magnetic field sources using signals obtained from the at least three SMD coils.

2. A position sensor according to claim 1, adapted to measure a signal indicative of the orientation of the sensor relative to a first magnetic field source located in front of the position sensor, wherein The at least three SMD coils include three SMD coils arranged on the FCB, so that when the FCB is set at the sensor in a folded / rolled state, the magnetic flux axes of the three SMD coils are parallel to each other and not coplanar; thereby, when the first magnetic field source is located in front of the sensor relative to the approximate direction of the magnetic flux axis, the signals obtained from the three SMD coils can be used to determine the two orientation angles of the position sensor relative to the first magnetic field source.

3. The position sensor according to claim 2, wherein: The three SMD coils are surface mounted to the surface of the FCB via surface mounting technology with their flux axes oriented parallel to the FCB surface; and wherein the FCB is arranged at the sensor in a folded / rolled form so that the folding / winding axis of the folded / rolled form is substantially parallel to the parallel flux axes of the three SMD coils thereon.

4. A position sensor according to any one of claims 1 to 3, adapted to measure a signal indicative of the position and orientation of the sensor relative to one or more second magnetic field sources; in, The at least three SMD coils include three SMD coils arranged on the FCB such that when the FCB is folded at the sensor, the flux axes of the three SMD coils span a 3D coordinate; The signals obtained from the three SMD coils can thereby be used to determine the position and orientation of the sensor relative to the one or more second magnetic field sources.

5. The position sensor according to claim 4, wherein: Two of the three SMD coils are surface mounted on the surface of the FCB via surface mounting technology with their magnetic flux axes oriented vertically relative to the FCB surface, so that when the FCB is set at the sensor in a folded / rolled state, the magnetic flux axes of the two SMD coils are not parallel; and the third SMD coil of the three SMD coils is surface mounted on the surface of the FCB via surface mounting technology with its magnetic flux axis oriented parallel to the FCB surface.

6. The position sensor according to any one of claims 1 to 5, wherein: The at least three SMD coils include at least five SMD coils surface mounted to one or more FCBs of the sensor, wherein a first subset of the at least five SMD coils comprises three SMD coils arranged such that when the FCB is arranged at the sensor in a folded / rolled state, their magnetic flux axes are parallel to each other and not coplanar; so that two orientation angles of the sensor relative to a first magnetic field source can be determined using signals obtained from the three SMD coils of the first subset, the first magnetic field source being located in front of the three SMD coils along the approximate direction of their magnetic flux axes; and The second subset of the at least five SMD coils includes three SMD coils, which are arranged so that when the FCB is set at the sensor in a folded / rolled state, their magnetic flux axes span 3D coordinates; thereby, the position and orientation of the sensor relative to one or more external second magnetic field sources can be determined using signals obtained from the three SMD coils of the second subset.

7. The position sensor according to any one of claims 1 to 6, wherein: At least one of the at least three SMD coils comprises a coil portion and at least one surface mounting portion arranged from at least one corresponding side of the coil portion; whereby the coil portion comprises a ferrite core and a conductive winding arrangement arranged in a spiral line directly above the outer surface of the ferrite core, the pitch of the spiral line not exceeding 12 to 13 μm, thereby enabling the SMD coil to have a compact size and high impedance.

8. The position sensor according to claim 7, wherein: The ferrite core includes a relative magnetic permeability μ of at least about 100 r material, and wherein the relative permeability of the material of the ferrite core is stable within a temperature range between approximately 20°C and 60°C with a tolerance of ±0.3%, thereby enabling consistent magnetic field measurements during operation under variable temperature conditions within the temperature range.

9. The position sensor according to any one of claims 7 or 8, wherein: The electrically conductive winding arrangement is manufactured directly on the outer surface of the ferrite core using photolithography.

10. The position sensor according to any one of claims 1 to 9, wherein: At least one of the at least three SMD coils is mounted with its magnetic flux axis oriented flat / parallel relative to the FCB surface and includes a coil portion and at least two SMT mounting portions, wherein the coil portion has a conductive winding arrangement, and the at least two SMT mounting portions are arranged from opposite sides of the coil portion and have at least two corresponding electrical contacts, wherein the at least two corresponding electrical contacts are electrically coupled to the FCB using SMT electrical connections and are respectively electrically connected to opposite ends of the conductive winding arrangement.

11. The position sensor according to any one of claims 1 to 10, wherein: At least one of the at least three SMD coils is mounted with its flux axis in a vertical / perpendicular orientation relative to the FCB surface and includes a coil portion and at least one SMT mounting portion, the coil portion having a conductive winding arrangement, the at least one SMT mounting portion being arranged from at least one side of the coil portion and having at least two electrical contacts, the at least two electrical contacts being electrically coupled to the FCB via an SMT electrical connection and being electrically connected to opposite ends of the conductive winding arrangement, respectively.

12. A medical device comprising a position sensor constructed according to any one of claims 1 to 11.

13. The medical device according to claim 12, wherein: The medical device is a catheter having an elongated housing including a main section having a longitudinal axis and a terminal section flexibly coupled at a distal end of the main section and including the first magnetic field source; wherein the position sensor is housed at the main section of the elongated housing such that the FCB is folded / rolled up about an axis parallel to the longitudinal axis; the first subset facilitates determining the orientation of the end section relative to the main section of the housing based on measurements of the magnetic field from the first magnetic field source, and the second subset facilitates determining the position and orientation of the main section relative to one or more external second magnetic field sources.

14. A method of manufacturing a magnetic position sensor suitable for use in a medical device, the method comprising: i. Provide flexible printed circuit board (FCB); ii. Providing at least three surface mounted coil devices (SMD coils); iii. mounting the at least three SMD coils on the FCB via surface mount technology (SMT); iv. folding the FCB having the at least three SMD coils into a tubular form, whereby the folding is performed so that the magnetic axes of the at least three SMD coils are not coplanar, thereby providing a magnetic field sensed by the at least three SMD coils from one or more magnetic field sources so as to enable measurement of at least one of the position and orientation of the sensor relative to the source.

15. The method according to claim 14, wherein: The medical device is a catheter having a tubular shaped body having a characteristic inner diameter of about 2.5 mm or less; and wherein the folding is performed so that the diameter of the FCB after being folded is smaller than the characteristic inner diameter of the body of the catheter; and the method includes placing the folded FCB within the body.

16. The method according to any one of claims 14 or 15, wherein: The magnetic position sensor is adapted to measure a signal indicative of the orientation of the sensor relative to a magnetic field source; the mounting of the at least three SMD coils comprises mounting three of the SMD coils on the FCB such that when the FCB is folded into the tubular form, the flux axes of the three SMD coils are parallel to each other and are not coplanar, thereby enabling the determination of two orientation angles relative to a magnetic field source using the signals obtained from the three SMD coils, the magnetic field source being located in front of the three SMD coils along the approximate direction of their flux axes.

17. The method according to any one of claims 14 to 16, wherein: The magnetic position sensor is adapted to measure signals indicative of the position and orientation of the sensor relative to one or more external magnetic field sources, and wherein the mounting of the at least three SMD coils comprises mounting three of the SMD coils on the FCB such that when the FCB is folded into the tubular form, the magnetic flux axes of the three SMD coils span 3D coordinates, thereby enabling the position and orientation of the sensor relative to the external magnetic field sources to be determined using the signals obtained from the three SMD coils.

18. The method according to any one of claims 14 to 17, wherein: The magnetic position sensor is adapted to measure a signal indicative of the orientation of the sensor relative to a first magnetic field source and a signal indicative of the position and orientation of the sensor relative to one or more second external magnetic field sources; the at least three SMD coils include at least five SMDs, and wherein the mounting includes mounting the at least five SMD coils such that when the FCB is folded into the tubular form, the following arrangement of the magnetic flux axes of the SMD coils is obtained: - said magnetic flux axes of a first subset of at least three of said at least five SMD coils are parallel to each other and not coplanar, thereby facilitating the determination of two orientation angles of said first magnetic field source relative to said first magnetic field source when said first magnetic field source is located in front of them along a general direction of the parallel magnetic flux axes of said three SMD coils of said first subset using signals obtained from said first subset; - the magnetic flux axis of a second subset comprising at least three of the at least five SMD coils spans a 3D coordinate, thereby facilitating determining the position and orientation of the sensor relative to the one or more external magnetic field sources using signals obtained from the first subset.

19. The method according to any one of claims 14 to 18, wherein: The mounting is performed using surface mounting technology and includes at least one of the following: - mounting two SMD coils with their flux axes oriented perpendicularly to the FCB surface, and mounting one SMD coil with its flux axes oriented parallel to the FCB surface, such that when the FCB is in a folded state, the flux axes of the two SMD coils and the flux axis of the one SMD coil span 3D coordinates; as well as - mounting three SMD coils with their flux axes in a parallel orientation relative to the FCB surface, such that when the FCB is folded about an axis parallel to the flux axes of the three SMD coils, the flux axes of the three SMD coils are parallel and non-coplanar.

20. The method according to any one of claims 14 to 19, wherein: The providing of the at least three SMD coils comprises manufacturing at least one of the SMD coils using a photolithographic method to form a spiral conductive winding directly on a ferrite core, wherein the photolithographic method comprises: a. applying a photoresist layer to cover at least the tubular section of the ferrite core; b. applying photolithography to pattern the photoresist layer, thereby forming a spiral pattern on the tubular segment covered by the photoresist layer; and c. electroplating the outer surface layer of the ferrite core at the exposed area of ​​the spiral pattern to form the conductive spiral winding directly on the outer surface layer of the tubular section of the ferrite core.

21. The method according to claim 20, wherein: One or more of the following: - the photolithography method is suitable for manufacturing high density conductive spiral windings, and wherein the pitch of the spiral pattern and accordingly the pitch of the conductive spiral windings is about 10 μm or less; The ferrite core comprises a material having a relative magnetic permeability μ of at least about 100 r and wherein the photolithography utilizes a photolithography light source that provides an optical power density (LDP) and wavelength suitable for patterning the photoresist while not causing substantial damage to the ferrite core; - said applying of said photoresist layer comprises applying a dry photoresist layer having a thickness of at least 8 μm, thereby enabling said electroplating to produce a narrow line width of said spiral conductive winding with a small pitch between adjacent lines and preventing diffuse plating between said adjacent lines; - before said electroplating, said photolithographic method comprises producing a seed layer on at least a portion of said ferrite core in order to increase the surface conductivity of said ferrite and facilitate said electroplating; - after said electroplating, said photolithographic method comprises removing remaining photoresist material from between said conductive spiral windings; - the ferrite core is provided with at least one surface mounting portion arranged from at least one corresponding side thereof; and the photoresist, photolithography and electroplating are applied to also form one or more conductive couplings between at least one end of the conductive spiral winding and one or more designated locations on the at least one surface mounting portion, thereby forming one or more SMT contacts.

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