Electromagnetic coil made of flexible circuit

Abstract

A method of manufacturing an electromagnet includes obtaining a first flexible PCB including one or more first electrically conductive coil traces and obtaining a second flexible PCB including one or more second electrically conductive coil traces. The first flexible PCB is bent into a shape having at least one curve or corner. After the first flexible PCB is bent into the shape, the second flexible PCB is then bent into the shape: the second flexible PCB is positioned adjacent to the first flexible PCB to be the same shape as the first flexible PCB.

Description

Technical Field

[0001] This disclosure relates to magnetic coils, and more specifically, to electromagnetic coils made using flexible printed circuit boards (PCBs). Background Technology

[0002] Electromagnets are traditionally formed by manually winding wire into a prescribed shape with a specified number of turns, thus creating a magnetic coil. This manual winding results in inaccurate and non-repeatable wire placement. This inaccuracy and non-repeatability complicate the calibration of systems using magnetic coils. Manual winding also limits its ability to shape the coil into a specified geometry. For example, sharp corners cannot be achieved because the turning radius is finite. Furthermore, the process of manual winding and connecting the resulting magnetic coil to a power source (e.g., an ammeter) is susceptible to human error.

[0003] Electromagnets have also been manufactured using single-layer flexible printed circuit boards (PCBs), where coils are formed by conductive traces on the PCB. However, the number of turns of the coil that can be implemented in a single layer is limited, thus limiting the strength of the electromagnet. Adding an additional layer to the PCB is impractical because it increases the rigidity of the PCB, which prevents the PCB from being bent into the desired shape of the electromagnet (i.e., specifying the geometry).

[0004] An example of the application of this type of electromagnet is the Wien filter, which uses perpendicular electric and magnetic fields to perform velocity filtering on charged particles (such as electrons). Wien filters are used in electron microscopes. Summary of the Invention

[0005] The above problem can be solved by using multiple flexible PCBs to form an electromagnet.

[0006] In some embodiments, a method includes obtaining a first flexible PCB including one or more first conductive coil traces and obtaining a second flexible PCB including one or more second conductive coil traces. The first flexible PCB is bent into a shape having at least one curve or corner. After bending the first flexible PCB into the shape, the second flexible PCB is bent into the shape: the second flexible PCB is positioned adjacent to the first flexible PCB to be conformal to the first flexible PCB.

[0007] In some embodiments, an electromagnet includes a first flexible PCB having one or more first conductive coil traces. The first flexible PCB is bent into a shape having at least one curve or corner. The electromagnet further includes a second flexible PCB bent into the shape and having one or more second conductive coil traces. The second flexible PCB is adjacent to and conforms to the first flexible PCB. Attached Figure Description

[0008] To better understand the various described implementation schemes, please refer to the following detailed embodiments in conjunction with the accompanying drawings.

[0009] Figure 1 An electromagnet comprising multiple flexible printed circuit boards (PCBs) bent into a specified shape, according to some embodiments, is shown.

[0010] Figure 2 The flexible PCB and associated connectors are shown according to some embodiments.

[0011] Figure 3A The diagram illustrates conductive coil traces on two flexible PCBs and electrical connections between the conductive coil traces, according to some embodiments.

[0012] Figure 3B Demonstration according to some embodiments Figure 3A A cross-section of a portion of a flexible PCB.

[0013] Figure 4 The system, according to some embodiments, includes a pair of flexible PCBs bent into a specified shape in an isotropic, concentric manner and also includes a connecting ring for an electrostatic deflector.

[0014] Figure 5 Cross-sectional and partial perspective views of an assembly of concentrically arranged electromagnets and electrostatic deflectors according to some embodiments are shown.

[0015] Figure 6A This is a flowchart illustrating a method for manufacturing an electromagnet using multiple flexible PCBs according to some embodiments.

[0016] Figure 6B This is to illustrate according to some embodiments Figure 6A The flowchart for the selection of methods.

[0017] In the accompanying drawings and specifications, the same component symbols refer to the corresponding parts. Detailed Implementation

[0018] Various embodiments will now be described in detail with reference to the accompanying drawings. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the various described embodiments. However, those skilled in the art will understand that the various described embodiments can be practiced without these specific details. In other instances, well-known methods, processes, components, circuits, and networks have not been described in detail to avoid unnecessarily obscuring aspects of the embodiments.

[0019] Figure 1An electromagnet 100 is illustrated according to some embodiments, comprising a plurality of flexible printed circuit boards (PCBs) 102 bent into a specified shape. The flexible PCBs 102 include a first flexible PCB 102-1 and a second flexible PCB 102-2. Each PCB 102 includes one or more conductive coil traces 104: the first flexible PCB 102-1 includes one or more conductive coil traces 104-1 and the second flexible PCB 102-2 includes one or more conductive coil traces 104-2. According to some embodiments, the second flexible PCB 102-2 is identical in shape to and substantially surrounds the first flexible PCB 102-1, except for a small gap 106 resulting from the fact that the first and second flexible PCBs 102-1 and 102-2 are of the same size. In some embodiments, one or more additional flexible PCBs 102 (each having one or more corresponding conductive coil traces 104) are located between the first flexible PCB 102-1 and the second flexible PCB 102-2. Adjacent flexible PCBs 102 can be mechanically connected (e.g., bonded together).

[0020] exist Figure 1 In one example, the flexible PCB 102 is bent into a specified shape that is a truncated cone, wherein the first flexible PCB 102-1 and the second flexible PCB 102-2 are arranged concentrically around a radial axis. Other shapes are possible. For example, the flexible PCB 102 can be bent into shapes having cylindrical, elliptical, rectangular, or polygonal cross-sections.

[0021] The current flowing through the conductive coil trace 104 generates a magnetic field in the space surrounded by the flexible PCB 102. The electromagnet 100 includes connectors 108-1 and 108-2 to supply current to the conductive coil trace 104. Connector 108-1 is mechanically connected to a first flexible PCB 102-1 and includes one or more conductors (e.g., conductive traces) electrically connected to one or more conductive coil traces 104-1. Connector 108-2 is mechanically connected to a second flexible PCB 102-2 and includes one or more conductors (e.g., conductive traces) electrically connected to one or more conductive coil traces 104-2. In some embodiments, connector 108-1 is a flexible PCB integrally formed with flexible PCB 102-1, and connector 108-2 is a flexible PCB integrally formed with flexible PCB 102-2. Connectors 108-1 and 108-2 are coupled to a power supply, such as a current source (not shown). In some embodiments, one or more conductive coil traces 104 on adjacent flexible PCBs 102 are electrically connected via contacts on the surface of the flexible PCBs 102. For example, assuming that flexible PCBs 102-1 and 102-2 are adjacent, one or more conductive coil traces 104-1 can be electrically connected via one or more contacts (e.g., contact 202) on flexible PCBs 102-1 and 102-2. Figure 2 Electrically connected to one or more conductive coil traces 104-2.

[0022] Figure 2 A flexible PCB 200 and associated connector 206 are shown according to some embodiments. Figure 2 As shown, the flexible PCB 200 has not yet been bent into the specified shape. The flexible PCB 200 (which may be flexible PCB 102) Figure 1 Examples of the flexible PCBs 200-1, 200-2, 200-3, and 200-4 include a first flexible PCB 200-1, a second flexible PCB 200-2, a third flexible PCB 200-3, and a fourth flexible PCB 200-4. Each of the flexible PCBs 200-2 includes one or more conductive coil traces (not shown) (e.g., conductive coil traces 302-1, 302-2, 304-1, and 304-2). Figure 3A The first flexible PCB 200-1 includes a contact 202 that can electrically contact a similar contact (not visible) on the second flexible PCB 200-2 to electrically connect conductive coil traces on the first and second PCBs 200-1 and 200-2. Similarly, the third flexible PCB 200-3 includes a contact 202 that can electrically contact a similar contact (not visible) on the fourth flexible PCB 200-4 to electrically connect conductive coil traces on the third and fourth PCBs 200-3 and 200-4.

[0023] Connector 206 includes a first arm 204-1 mechanically and electrically connected to a first flexible PCB 200-1 and a second arm 204-2 mechanically and electrically connected to a third flexible PCB 200-3. The first arm 204-1 may be an example of connector 108-1 and the second arm 204-2 may be an example of connector 108-2 (or vice versa). In some embodiments, connector 206, including the first arm 204-1 and / or the second arm 204-2, is integrally formed with the first flexible PCB 200-1 and / or the third flexible PCB 200-3. Connector 206 is mechanically and electrically connected to contact pad 208 and includes conductors (not shown) (e.g., conductors 312 and 314). Figure 3A Traces 406-1 and 406-2, Figure 4 The conductive coil traces on the flexible PCBs 200-1 to 200-4 are electrically coupled to the contacts 210 on the contact pads 208. The conductors in the connector 206 may be conductive traces. The contacts 210 may be electrically coupled to a power source (e.g., a current supply) and thus allow the conductive coil traces on the flexible PCBs 200-1 to 200-4 to be electrically coupled to a power source.

[0024] In some embodiments, four flexible PCBs 200-1 to 200-4 may be bent into the same shape and positioned close to each other (i.e., adjacent) in a conformal, concentric manner to form a single electromagnet (e.g., electromagnet 100). Figure 1 In this example, the conductive coil traces on the four flexible PCBs 200-1 to 200-4 can be connected in series, so that the current polarity of the conductive coil traces on all four flexible PCBs 200-1 to 200-4 is the same. The additional conductive coil traces provided by the third and fourth flexible PCBs 200-3 and 200-4 result in a stronger electromagnet than if only two flexible PCBs 200-1 and 200-2 were used.

[0025] In some other embodiments, the first and second flexible PCBs 200-1 and 200-2 can be bent into the same shape and positioned close to each other (i.e., adjacent) in a conformal, concentric manner to form a first electromagnet (e.g., first electromagnet 100). Figure 1 The third and fourth flexible PCBs 200-3 and 200-4 can be bent into the same shape and positioned close to each other (i.e., adjacent) in a conformal and concentric manner to form a second electromagnet different from the first electromagnet (e.g., the second electromagnet 100). Figure 1 ).

[0026] In some embodiments, the conductive coil traces in the first and second flexible PCBs 200-1 and 200-2 are connected in series, such that the current polarity of the conductive coil traces on the first and second PCBs 200-1 and 200-2 is the same. The first and second flexible PCBs 200-1 and 200-2 thus form an electromagnet. However, one or more conductive coil traces in the third flexible PCB 200-3 are not connected in series to one or more conductive coil traces in the fourth flexible PCB 200-4. Instead, one or more conductive coil traces in the third flexible PCB 200-3 are wired to conduct current with a polarity opposite to that of the current conducted by one or more conductive coil traces in the fourth flexible PCB 200-4. This configuration can be achieved by electrically coupling the conductive coil traces of the third and fourth PCBs 200-3 and 200-4 to corresponding contacts 210 on contact pads 208 that provide the desired polarity of current. In this configuration, the magnetic field generated by one or more conductive coil traces in the fourth flexible PCB 200-4 will be opposite to and thus cancel out the magnetic field generated by one or more conductive coil traces in the third flexible PCB 200-3. The resulting combination of the third and fourth PCBs 200-3 and 200-4, positioned concentrically and isomorphically close to each other (i.e., adjacent), will generate a heater that can be used to counteract thermal variations in the combination of the first and second PCBs 200-1 and 200-2 (positioned concentrically and isomorphically close to each other). When the current supplied to the first and second PCBs 200-1 and 200-2 decreases (or increases), the current supplied to the third and fourth PCBs 200-3 and 200-4 increases (or decreases) by a corresponding amount to counteract the heating changes, thus resulting in constant overall heating. Constant heating is expected to maintain calibration and ensure consistent system performance.

[0027] Figure 3A The illustration shows conductive coil traces and electrical connections between conductive coil traces on two flexible PCBs 300-1 and 300-2 according to some embodiments. Flexible PCBs 300-1 and 300-2 may be flexible PCBs 200-1 and 200-2 (…). Figure 2 Flexible PCBs 200-3 and 200-4 Figure 2 ) and / or flexible PCBs 102-1 and 102-2 Figure 1 Examples of flexible PCBs 300-1 and 300-2 include a pair of conductive coil traces 302-1 and 302-2 on a first side 308 and a pair of conductive coil traces 304-1 and 304-2 on a second side 310. The first side 308 and the second side 310 are separated by an insulating (e.g., polyimide) layer (e.g., insulating layer 322). Figure 3BSeparation. The conductive coil traces 302-1 and 302-2 on the first side 308 are separated by a first insulating (e.g., polyimide) covering layer (e.g., covering layer 320). Figure 3B Similarly, the conductive coil traces 304-1 and 304-2 on the second side 310 are covered by a second insulating (e.g., polyimide) covering layer (e.g., covering layer 324). Figure 3B )cover.

[0028] Conductive coil traces 302 and 304 are rectangular spirals, each with a specified number of turns. Thus, the consecutive segments of the rectangular spirals are perpendicular to each other and intersect at approximately right angles (although in some embodiments, the angles may have a degree of curvature). Figure 3A The number of turns shown is 4, but the number of turns is generally variable. For example, the number of turns can be 5, 6, or more. Furthermore, each of the flexible PCBs 300-1 and 300-2 may have only a single conductive coil trace 302 on the first side 308 and only a single conductive coil trace 304 on the second side 310, or may have more than two conductive coil traces 302 on the first side 308 and more than two conductive coil traces 304 on the second side 310. In some embodiments, the conductive coil traces 302 and 304 are copper.

[0029] Conductive coil trace 302-1 is electrically connected to conductive coil trace 302-2; both are formed by a single long trace, as shown. The inner end of conductive coil trace 302-1 is electrically connected to the inner end of conductive coil trace 304-1 via passage 306-1. Similarly, the inner end of conductive coil trace 302-2 is electrically connected to the inner end of conductive coil trace 304-2 via passage 306-2. In some embodiments, passages 306-1 and 306-2 are copper. The outer end of conductive coil trace 304-1 of flexible PCB 300-1 is connected via contact 307 (e.g., contact 202). Figure 2 The outer end of the conductive coil trace 304-2 of the flexible PCB 300-2 is electrically connected to the conductor 312 (e.g., connector 206). Figure 2 ) and / or connector 108 ( Figure 1 Conductive trace in ); Conductive trace 406, Figure 4 The outer end of the conductive coil trace 304-2 of the flexible PCB 300-1 is electrically connected to conductor 314 (e.g., connector 206). Figure 2 ) and / or connector 108 ( Figure 1 Conductors 312 and 314 supply current to conductive coil traces 302 and 304, which are connected in series between conductors 312 and 314. Figure 3AThis example demonstrates a series connection of conductive coil traces 302 and 304; other examples are possible.

[0030] Figure 3B This demonstrates a flexible PCB 300 (e.g., flexible PCB 300-1 or 300-2) according to some embodiments. Figure 3A A cross-section of a portion of the conductor coil trace 302 (e.g., conductor coil trace 302-1 or 302-2). Figure 3A Located on the first side of PCB 300. Conductive coil trace 304 (e.g., conductive coil trace 304-1 or 304-2, Figure 3A Located on the second side of PCB 300. An insulating (e.g., polyimide) layer 322 in the middle of the flexible PCB 300 separates conductive coil trace 302 from conductive coil trace 304. A passage 306 electrically connects conductive coil trace 302 and conductive coil trace 304. In some embodiments, conductive coil traces 302 and 304 and passage 306 are copper. An insulating (e.g., polyimide) cover layer 320 covers conductive coil trace 302 on the first side, and an insulating (e.g., polyimide) cover layer 324 covers conductive coil trace 304 on the second side. The flexible PCB 300 has one or more contacts (not visible) (e.g., contact 202, ...). Figure 2 The conductive coil traces 302 and 304 are used for electrically connecting conductive coil traces on other flexible PCBs (e.g., to another example of flexible PCB 300). Flexible PCB 300 also has one or more contacts (not visible) for electrically connecting conductive coil traces 302 and 304 to connectors (e.g., connector 206). Figure 2 Connector 108, Figure 1 Connector 404, Figure 4 The conductor in ).

[0031] Figure 4 The system illustrated according to some embodiments includes a pair of flexible PCBs 400-1 and 400-2 bent into a designated shape in an isotropic and concentric manner such that the flexible PCB 400-2 substantially surrounds the flexible PCB 400-1. Each of the flexible PCBs 400-1 and 400-2 includes one or more conductive coil traces (not shown). For example, the flexible PCBs 400-1 and 400-2 may be flexible PCBs 102-1 and 102-2 (…). Figure 1 ), 200-1 and 200-2 ( Figure 2 ), 200-3 and 200-4 ( Figure 2 ) and / or 300-1 and 300-2 ( Figure 3AThe implementation scheme is as follows. One or more conductive coil traces of flexible PCBs 400-1 and 400-2 are electrically connected to contact pad 408 (e.g., contact pad 208) via the first arm 402-1 of connector 404. Figure 2 The conductive trace, including trace 406-1 (e.g., another trace on the invisible side of the first arm 402-1), completes the circuitry between the contact pad 408 and the conductive coil traces of the flexible PCBs 400-1 and 400-2. The connector includes a second arm 402-2 (e.g., arm 204-2). Figure 2 ), which has one or more conductive traces including trace 406-2 (e.g., another trace on the invisible side of the second arm 402-2) for electrical connection to conductive coil traces on a second pair of flexible PCBs (not shown) (e.g., relative to Figure 2 (As described) or alternatively used for electrical connection to one or more conductive coil traces on the flexible PCB400-2.

[0032] According to some embodiments, Figure 4 The system also includes components for electrostatic deflectors (e.g. Figure 5 Connecting ring 412 (as shown in the diagram). Connecting ring 412 includes a corresponding pole (e.g., pole 504) provided to the electrostatic connector. Figure 5 The contact 414 is electrically connected to the connector 410. The connecting ring 412 is electrically connected to the contact pad 408 via the connector 410 (e.g., via conductive traces in the connector 410). The contact pad 408 can be coupled to a power supply (e.g., a voltage supply) for applying bias to the poles of the electrostatic deflector.

[0033] Figure 5 Cross-sectional and partial perspective views of an assembly 500 having concentrically arranged electromagnets 502 and electrostatic deflectors according to some embodiments are shown. The assembly 500 may be a Wien filter (e.g., for use in an electron microscope). The electromagnets 502 include multiple flexible PCBs (e.g., flexible PCBs 102-1 and 102-2) with conductive coil traces. Figure 1 ); 200-1, 200-2, 200-3 and / or 200-4 ( Figure 2 ); 300-1 and 300-2 ( Figure 3A ); 400-1 and 400-2 ( Figure 4Multiple flexible PCBs are arranged concentrically and isomorphically adjacent to each other. An electrostatic deflector comprises multiple poles 504 (e.g., eight poles 504, resulting in an octet configuration), each having a conductive surface. The poles 504 are radially positioned within an opening surrounded by an electromagnet 502. By applying a bias voltage to the poles 504, an electric field is generated within the opening surrounded by the electromagnet 502. Applying a bias voltage to the poles 504 while supplying current to the multiple flexible PCBs results in simultaneous electric and magnetic fields within the opening. These electric and magnetic fields can be perpendicular. A connecting ring 506 (e.g., connecting ring 412) is also included. Figure 4 Provides electrical contacts (invisible) for pole 504 (e.g., contact 414). Figure 4 Screw 508 or another suitable connecting mechanism holds the connecting ring 506 in place and forces the corresponding electrical contact into contact with pole 504.

[0034] Figure 6A This demonstrates the use of multiple flexible PCBs to manufacture electromagnets (e.g., electromagnet 100) according to some embodiments. Figure 1 Electromagnet 502, Figure 5 A flowchart of method 600 (or, in some embodiments, a device having a zero magnetic field) is shown. In method 600, obtaining (602) includes one or more first conductive coil traces (e.g., conductive coil trace 104-1, Figure 1 Conductive coil traces 302-1, 302-2, 304-1, and 304-2, Figure 3A The first flexible PCB (e.g., flexible PCB 102-1) Figure 1 ), 200-1 or 200-3 ( Figure 2 ), 300-1 Figure 3A ), 400-1 Figure 4 In some embodiments, one or more first conductive traces are (604) rectangular spiral traces. Also obtained is (606) a trace comprising one or more second conductive coil traces (e.g., conductive coil trace 104-2). Figure 1 Conductive coil traces 302-1, 302-2, 304-1, and 304-2, Figure 3A The second flexible PCB (e.g., flexible PCB102-2) Figure 1 ), 200-2 or 200-4 ( Figure 2 ), 300-2 Figure 3A ), 400-2 Figure 4 In some embodiments, one or more second conductive traces are (608) rectangular spiral traces.

[0035] The first flexible PCB is bent (610) into a shape having at least one curve or corner. In some embodiments, the shape is (612) a truncated cone. Other examples of the shape include (but are not limited to) shapes having a cylindrical, elliptical, rectangular, or polygonal cross-section. In some embodiments, the first flexible PCB is bent by wrapping (614) the first flexible PCB with a fixing device having the shape. The fixing device is then removed (e.g., after all the flexible PCBs have been bent into the shape).

[0036] After the first flexible PCB has been bent into the shape described, the second flexible PCB is bent (616) into the shape described: the second flexible PCB is positioned adjacent to the first flexible PCB to be conformally shaped to the first flexible PCB (e.g., concentrically). In some embodiments, the second flexible PCB bent into the shape described is mechanically connected (618) to the first flexible PCB. For example, the second flexible PCB is attached to the first flexible PCB using an adhesive (620).

[0037] In some embodiments, one or more first conductive coil traces are connected in series (622) with one or more second conductive coil traces (e.g., via contact 202). Figure 2 ), through contact 307 ( Figure 3A Therefore, the first and second flexible PCBs arranged according to method 600 form an electromagnet.

[0038] In some other embodiments, one or more second conductive coil traces are configured (624) to conduct current with a polarity opposite to that of one or more first conductive coil traces (i.e., one or more first conductive coil traces conduct current with a first polarity and one or more second conductive coil traces conduct current with a second polarity opposite to the first polarity). Therefore, the magnetic field generated by the first flexible PCB cancels out the magnetic field generated by the second flexible PCB, resulting in a zero-magnetic-field device used as a heater.

[0039] Figure 6B This is a flowchart illustrating an optional continuation of method 600 according to some embodiments. In this continuation of method 600, (632) is obtained comprising one or more third conductive coil traces (e.g., conductive coil traces 302-1, 302-2, 304-1, and 304-2, Figure 3A The third flexible PCB (e.g., flexible PCB 200-3) Figure 2 Example of PCB 300-1, Figure 3A In some embodiments, one or more third conductive coil traces are (634) rectangular spiral traces. Also obtained is (636) a trace comprising one or more fourth conductive coil traces (e.g., conductive coil traces 302-1, 302-2, 304-1, and 304-2). Figure 3AThe fourth type of flexible PCB (e.g., flexible PCB 200-4). Figure 2 Example of PCB 300-2, Figure 3A In some embodiments, one or more fourth conductive coil traces are (638) rectangular spiral traces.

[0040] After the first and second flexible PCBs are bent into the stated shape, the third flexible PCB is bent (640) into the stated shape: the third flexible PCB is positioned adjacent to the second flexible PCB to be conformally shaped to the second flexible PCB (e.g., concentrically). In some embodiments, the third flexible PCB bent into the stated shape is mechanically connected (642) to the second flexible PCB. For example, the third flexible PCB is attached to the second flexible PCB using an adhesive (644).

[0041] After the first, second, and third flexible PCBs are bent into the stated shape, a fourth flexible PCB is bent (646) into the stated shape: the fourth flexible PCB is positioned adjacent to the third flexible PCB to be conformally shaped to the third flexible PCB (e.g., concentrically). In some embodiments, the fourth flexible PCB bent into the stated shape is mechanically connected (648) to the third flexible PCB. For example, the fourth flexible PCB is attached to the third flexible PCB using an adhesive (650).

[0042] In some embodiments, electrical connections (652) are made between one or more third conductive coil traces and one or more fourth conductive coil traces (e.g., via contact 202). Figure 2 ), through contact 307 ( Figure 3A For example, one or more third and fourth conductive coil traces are configured (654) to conduct currents with the same polarity as one or more first and second conductive coil traces (e.g., one or more first, second, third, and fourth conductive coils are connected in series). Thus, the four flexible PCBs arranged according to method 600 form an electromagnet. In another example, one or more third and fourth conductive coil traces are configured (656) to conduct currents with polarity opposite to that of one or more first and second conductive coil traces (i.e., one or more first and second conductive coil traces conduct currents with a first polarity and one or more third and fourth conductive coil traces conduct currents with a second polarity opposite to the first polarity). Therefore, the magnetic field generated by the first and second flexible PCBs cancels out the magnetic field generated by the third and fourth flexible PCBs, resulting in a zero-magnetic-field device used as a heater.

[0043] In some other embodiments, one or more first and second conductive coil traces are configured (658) to conduct currents of the same polarity (e.g., connected in series), such that the first and second flexible PCBs arranged according to method 600 form an electromagnet. However, one or more third conductive coil traces are configured (658) to conduct currents of the opposite polarity to one or more fourth conductive coil traces (i.e., one or more third conductive coil traces conduct currents of the first polarity and one or more fourth conductive coil traces conduct currents of the second polarity opposite to the first polarity). Therefore, the third and fourth flexible PCBs arranged according to method 600 form a zero-magnetic-field device that serves as a heater. This heater can counteract heating variations in the electromagnet formed by the first and second flexible PCBs.

[0044] Method 600 may include more or fewer operations. The order of non-sequential dependent operations may be changed and / or two or more operations may be combined into a single operation. For example, steps 632 and 636 may be performed simultaneously with steps 602 and 606 before any other steps are performed. In another example, the steps of bending the corresponding flexible PCB, mechanically connecting the corresponding flexible PCB to another PCB, and / or electrically connecting the corresponding flexible PCB to another PCB may be combined into a single step.

[0045] The method 600 disclosed herein and the flexible PCB arrangement allow multiple conductive coil layers to be stacked within an electromagnet, resulting in a strong magnetic field while still achieving the desired electromagnetic shape. The magnetic coils (i.e., conductive coil traces) can have sharp corners or tight turning radii. Such electromagnets can be manufactured repeatably with very small errors.

[0046] For the purpose of explanation, the above description has been described with reference to specific embodiments. However, the illustrative statements above are not intended to be exhaustive or to limit the scope of the claims to the precise form disclosed. Many modifications and variations can be made in light of the above teachings. The embodiments have been chosen to best explain the basic principles of the claims and their practical application, thereby enabling those skilled in the art to best use the embodiments and various modifications suitable for the intended particular purpose.

Claims

1. A method for manufacturing an electromagnet, comprising: A first flexible PCB comprising one or more first conductive coil traces is obtained; A second flexible PCB comprising one or more second conductive coil traces is obtained; The first flexible PCB is bent into a shape having at least one curve or corner; After bending the first flexible PCB into the shape, bending the second flexible PCB into the shape includes positioning the second flexible PCB adjacent to the first flexible PCB so as to be identical in shape to and surround the first flexible PCB. and Electrically connect the one or more first conductive coil traces to the one or more second conductive coil traces.

2. The method according to claim 1, wherein the shape is a truncated cone.

3. The method according to claim 1, wherein the one or more first conductive coil traces and the one or more second conductive coil traces are rectangular spiral traces.

4. The method according to claim 1, wherein: The bending includes causing the first flexible PCB to wrap around the fixing device; and The method further includes removing the fixing device after the first flexible PCB has wrapped the fixing device.

5. The method of claim 1, further comprising using an adhesive to mechanically attach the second flexible PCB, which is bent into the shape, to the first flexible PCB.

6. The method according to claim 1, wherein: The one or more first conductive coil traces include a first conductive coil trace on a first side of the first flexible PCB and a second conductive coil trace on a second side of the first flexible PCB, wherein the first flexible PCB includes an insulating layer separating the first side and the second side; The first flexible PCB further includes a pathway through the insulating layer that electrically connects the first conductive coil trace and the second conductive coil trace; The one or more second conductive coil traces include a third conductive coil trace on a first side of the second flexible PCB and a fourth conductive coil trace on a second side of the second flexible PCB, wherein the second flexible PCB includes an insulating layer separating the first side and the second side; and The second flexible PCB further includes a pathway through the insulating layer that electrically connects the third conductive coil trace to the fourth conductive coil trace.

7. The method of claim 1, further comprising: Obtain a third flexible PCB that includes one or more third conductive coil traces; A fourth flexible PCB is obtained, comprising one or more fourth conductive coil traces; After bending the first flexible PCB and the second flexible PCB into the shape, bending the third flexible PCB into the shape includes positioning the third flexible PCB adjacent to the second flexible PCB to be identical in shape to the second flexible PCB. and After bending the first flexible PCB, the second flexible PCB, and the third flexible PCB into the shape, bending the fourth flexible PCB into the shape includes positioning the fourth flexible PCB adjacent to the third flexible PCB to be identical in shape to the third flexible PCB.

8. The method of claim 7, further comprising: Electrically connect the one or more third conductive coil traces to the one or more fourth conductive coil traces.

9. The method of claim 7, further comprising configuring the one or more third conductive coil traces and the one or more fourth conductive coil traces to conduct currents with the same polarity as the one or more first conductive coil traces and the one or more second conductive coil traces.

10. The method of claim 7, further comprising: The one or more first conductive coil traces and the one or more second conductive coil traces are configured to conduct current with a first polarity; and The one or more third conductive coil traces and the one or more fourth conductive coil traces are configured to conduct current with a second polarity opposite to the first polarity.

11. The method of claim 7, further comprising: The one or more first conductive coil traces and the one or more second conductive coil traces are configured to conduct current with the same polarity. and The one or more third conductive coil traces and the one or more fourth conductive coil traces are configured to conduct current with opposite polarities.

12. The method of claim 1, further comprising concentrically positioning the electrostatic deflector with the first flexible PCB and the second flexible PCB.

13. An electromagnet comprising: A first flexible PCB includes one or more first conductive coil traces, the first flexible PCB being bent into a shape having at least one curve or corner. and A second flexible PCB is bent into the shape described above and includes one or more second conductive coil traces. The second flexible PCB is adjacent to the first flexible PCB, is shaped to the first flexible PCB, and surrounds the first flexible PCB. The one or more first conductive coil traces are electrically connected to the one or more second conductive coil traces.

14. The electromagnet of claim 13, wherein the shape is a truncated cone.

15. The electromagnet of claim 13, wherein the one or more first conductive coil traces and the one or more second conductive coil traces are rectangular spiral traces.

16. The electromagnet of claim 13, wherein the first flexible PCB and the second flexible PCB are mechanically connected by an adhesive.

17. The electromagnet according to claim 13, wherein: The one or more first conductive coil traces include a first conductive coil trace on a first side of the first flexible PCB and a second conductive coil trace on a second side of the first flexible PCB, wherein the first flexible PCB includes an insulating layer separating the first side and the second side; The first flexible PCB further includes a pathway through the insulating layer that electrically connects the first conductive coil trace and the second conductive coil trace; The one or more second conductive coil traces include a third conductive coil trace on a first side of the second flexible PCB and a fourth conductive coil trace on a second side of the second flexible PCB, wherein the second flexible PCB includes an insulating layer separating the first side and the second side; and The second flexible PCB further includes a pathway through the insulating layer that electrically connects the third conductive coil trace to the fourth conductive coil trace.

18. The electromagnet of claim 13, further comprising: A third flexible PCB, which is bent into the shape described above and includes one or more third conductive coil traces, the third flexible PCB being adjacent to and having the same shape as the second flexible PCB; and A fourth flexible PCB, which is bent into the shape described above and includes one or more fourth conductive coil traces, the fourth flexible PCB being adjacent to and having the same shape as the third flexible PCB.

19. The electromagnet of claim 18, wherein the one or more third conductive coil traces and the one or more fourth conductive coil traces are configured to conduct currents with the same polarity as the one or more first conductive coil traces and the one or more second conductive coil traces.

20. The electromagnet according to claim 18, wherein: The one or more first conductive coil traces and the one or more second conductive coil traces are configured to conduct current with a first polarity; and The one or more third conductive coil traces and the one or more fourth conductive coil traces are configured to conduct current with a second polarity opposite to the first polarity.

21. The electromagnet of claim 13, further comprising an electrostatic deflector concentrically disposed with the first flexible PCB and the second flexible PCB.

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