PATENT DOCUMENT

Publication Number: US-11258343-B2
Application Number: US-201815985619-A
Country: US
Kind Code: B2

Title: Double helix actuator with magnetic sections having alternating polarities

Abstract:
A double helix actuator is disclosed that includes a double helix coil wound around a movable proof mass that is enclosed within a magnetic structure. The double helix coil and the magnetic structure are arranged relative to each other so that the magnetic field generated by the entirety of the double helix coil contributes to a linear force direction of the actuator. The double helix actuator produces a greater linear force density compared to traditional racetrack coil actuators, where only a portion of the coil contributes to the linear force. The double helix actuator also produces torque in addition to linear force which allows the double helix to provide unique haptic sensations in a variety of applications.

Claims:
What is claimed is: 
     
       1. A double helix actuator, comprising:
 a cover assembly having a top surface, two opposing sides and two opposing ends, the cover assembly including:
 a first set of magnetic sections of alternating polarity arranged in a first row and attached to a first side of the cover assembly, a second set of magnetic sections of alternating polarity arranged in a second row and attached to a second side of the cover assembly; a third set of magnetic sections of alternating polarity arranged in a third row along the top surface of the cover assembly and disposed between the first and second sets of magnetic sections, each magnetic section in the third set of magnetic sections arranged to have a magnetic field direction that is orthogonal to magnetic field directions of the first and second sets of magnetic sections; and 
 
 a main assembly attached to the cover assembly, the main assembly including:
 an inner assembly including a proof mass and a coil helically-wound around the proof mass, such that the magnetic fields provided by the first, second and third sets of magnetic sections follow a direction of a coil current; and 
 a base assembly including a base and a fourth set of magnetic sections of alternating polarity arranged in a fourth row on the base, the base attached to the cover assembly and forming a cavity for receiving the inner assembly, each magnetic section in the fourth set of magnetic sections arranged to have a magnetic field direction that is in the same direction as the magnetic field direction of the third set of magnetic sections. 
 
 
     
     
       2. The double helix actuator of  claim 1 , wherein the coil is helically-wound in two layers around the proof mass, such that for each winding of the coil the magnetic field direction and the coil current direction follow each other. 
     
     
       3. The double helix actuator of  claim 1 , wherein one or more spaces are reserved in the double helix actuator for one or more crash stops, to allow proof mass travel or to introduce displacement using at least one of flexures or springs. 
     
     
       4. The double helix actuator of  claim 1 , wherein the first set of magnetic sections are polarized inward toward the coil and the second set of magnetic sections are polarized outward away from the coil. 
     
     
       5. The double helix actuator of  claim 1 , wherein the third set of magnetic sections are arranged to be opposite fourth magnetic sections of the same polarity. 
     
     
       6. The double helix actuator of  claim 1 , further comprising:
 a controller coupled to the double helix actuator, the controller generating and sending a drive signal to the double helix actuator to drive the proof mass into motion, the drive signal being adjusted by the controller based on one or more feedback signals that are generated in response to the motion. 
 
     
     
       7. The double helix actuator of  claim 6 , wherein the feedback signals include a back-electromotive force (EMF) voltage signal generated in response to the motion. 
     
     
       8. The double helix actuator of  claim 6 , further comprising one or more magnetic sensors proximate to the proof mass, and wherein the feedback signals include voltage signals generated by the one or more magnetic sensors in response to the motion.

Description:
TECHNICAL FIELD 
     This disclosure relates generally to electromechanical actuators for haptic engines and other applications. 
     BACKGROUND 
     Linear actuator architectures are often used in mobile devices to provide tap and haptic sensations. A traditional linear actuator architecture relies on moving alternating magnets with fixed racetrack coils, fixed alternating magnets with moving racetrack coils or moving inward facing magnets wrapped by a coil. With the traditional racetrack coil architecture, the force density at a fixed power consumption is limited to the cross-sectional area of the racetrack coils and the average intensity of the magnetic field incident normal to the direction of current in the racetrack coils. Only the portion of the racetrack coils where current flows orthogonal to the intended force direction contributes to force density. 
     SUMMARY 
     A double helix actuator is disclosed that includes a double helix coil wound around a movable proof mass that is enclosed within a magnetic structure. The double helix coil and the magnetic structure are arranged relative to each other so that the magnetic field generated by the entirety of the double helix coil contributes to a linear force direction of the actuator. The double helix actuator produces a greater linear force density compared to traditional racetrack coil actuators, where only a portion of the coil contributes to the linear force. The double helix actuator also produces torque in addition to linear force which allows the double helix to provide unique haptic sensations in a variety of applications. 
     In an embodiment, a double helix actuator comprises: a cover assembly having a top surface, two opposing sides and two opposing ends, the cover assembly including: a first set of magnets of alternating polarity arranged in a first row and attached to a first side of the cover assembly, a second set of magnets of alternating polarity arranged in a second row and attached to a second side of the cover assembly; a third set of magnets of alternating polarity arranged in a third row along the top surface of the cover assembly and disposed between the first and second sets of magnets, each magnet in the third set of magnets arranged to have a magnetic field direction that is orthogonal to magnetic field directions of the first and second sets of magnets; and a main assembly attached to the cover assembly, the main assembly including: an inner assembly including a moving mass and a coil helically-wound around the moving mass, such that the magnetic fields provided by the first, second and third sets of magnets follow a direction of the coil current; and a base assembly including a base and a fourth set of magnets of alternating polarity arranged in a fourth row on the base, the base attached to the cover assembly and forming a cavity for receiving the inner assembly, each magnet in the fourth set of magnets arranged to have a magnetic field direction that is in the same direction as the magnetic field direction of the third set of magnets. 
     In an embodiment, a cylindrical double helix actuator comprises: a cylindrical housing; flexure caps attached to opposite ends of the cylindrical housing forming a cavity, each flexure cap have a flexure; a helically magnetized core disposed within the cavity between the flexures of the flexure caps; and a flex coil helically-wound around the helically magnetized core in accordance with a winding pattern that is an alternating solenoid, with alternating dipole polarization and continuous helical polarization. 
     In an embodiment, an electronic device comprises: a haptic engine comprising: a cover assembly having a top surface, two opposing sides and two opposing ends, the cover assembly including: a first set of magnets of alternating polarity arranged in a first row and attached to a first side of the cover assembly, a second set of magnets of alternating polarity arranged in a second row and attached to a second side of the cover assembly; a third set of magnets of alternating polarity arranged in a third row along the top surface of the cover assembly and disposed between the first and second sets of magnets, each magnet in the third set of magnets arranged to have a magnetic field direction that is orthogonal to magnetic field directions of the first and second sets of magnets; and a main assembly attached to the cover assembly, the main assembly including: an inner assembly including a moving mass and a coil helically-wound around the moving mass, such that the magnetic fields provided by the first, second and third sets of magnets follow a direction of the coil current; and a base assembly including a base and a fourth set of magnets of alternating polarity arranged in a fourth row on the base, the base attached to the cover assembly and forming a cavity for receiving the inner assembly, each magnet in the fourth set of magnets arranged to have a magnetic field direction that is in the same direction as the magnetic field direction of the third set of magnets; a controller coupled to the haptic engine, the controller generating and sending a drive signal to the haptic engine to drive the haptic engine into motion, the drive signal being adjusted by the controller based on one or more feedback signals from the haptic engine that are generated in response to the motion, the frequency and duration of the drive signal determined by a request to generate a haptic sensation; one or more processors; memory storing instructions that when executed by the one or more processors, cause the one or more processors to perform one or more operations comprising: sending, to the controller, the request to generate the haptic sensation. 
     Particular embodiments disclosed herein provided one or more of the following advantages. The double helix actuator architecture enables volume reduction of a linear actuator while maintaining critical performance parameters. The architecture allows more space for a bigger battery. The single stage design enables simple scaling to a larger force actuator. The architecture enables haptics for high-mass products that require far more force than traditional haptic engines. The torque produced along with the linear force enables a unique haptic response. The magnet and coil geometry result in a greater force density within a fixed enclosure volume than conventional racetrack coil architectures. The magnet and coil geometry result in a greater motor efficiency within a fixed enclosure volume than conventional racetrack coil architectures. The output of the double helix actuator architecture contains multiple degrees of freedom, making the double helix architecture suitable for integration into a variety of systems with different form factor and power constraints. 
     The details of the disclosed implementations are set forth in the drawings and the description below. Other features, objects and advantages are apparent from the description, drawings and claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a perspective view of a traditional racetrack coil actuator that produces force in a portion of the coil. 
         FIG. 1B  is a top view of the traditional racetrack coil actuator. 
         FIG. 1C  is a side view of the traditional racetrack coil actuator. 
         FIG. 2A  is a perspective view of a rectangular, double helix actuator that produces force throughout the entirety of the coil, according to an embodiment. 
         FIG. 2B  is a top view of the rectangular, double helix actuator showing the force direction, according to an embodiment. 
         FIG. 2C  is a side view of the rectangular, double helix actuator, according to an embodiment. 
         FIG. 3A  is a perspective view of a cylindrical, double helix actuator, according to an embodiment. 
         FIG. 3B  is a side view of the cylindrical, double helix actuator showing the force direction, according to an embodiment. 
         FIG. 4A  is a perspective view of an assembled double helix actuator, according to an embodiment. 
         FIG. 4B  illustrates the various components of the assembly shown in  FIG. 4A , according to an embodiment. 
         FIG. 5A  is a side view of the double helix actuator illustrating magnet orientation, according to an embodiment. 
         FIG. 5B  is a bottom view of the double helix actuator illustrating magnet orientation, according to an embodiment. 
         FIG. 5C  is an end view of the double helix actuator illustrating magnet orientation, according to an embodiment. 
         FIG. 5D  is a blow-up view of an inner assembly of the double helix actuator illustrating a coil winding pattern, according to an embodiment. 
         FIG. 5E  is an alternative perspective view of the double helix actuator illustrating magnet orientation, according to an embodiment. 
         FIG. 6A  is a side view of the double helix actuator illustrating current orientation, according to an embodiment. 
         FIG. 6B  is a bottom view of the double helix actuator illustrating current orientation, according to an embodiment. 
         FIG. 6C  is an end view of the double helix actuator illustrating current orientation, according to an embodiment. 
         FIG. 7A  is a side view of the double helix actuator illustrating coil force, according to an embodiment. 
         FIG. 7B  is a bottom view of the double helix actuator illustrating coil force, according to an embodiment. 
         FIG. 7C  is an end view of the double helix actuator illustrating coil force, according to an embodiment. 
         FIG. 8  illustrates force and torque production due to a helical winding angle, according to an embodiment. 
         FIG. 9  is a block diagram of a control system for controlling the double helix actuator shown in  FIGS. 1-8 , according to an embodiment. 
         FIG. 10  illustrates a cylindrical double helix actuator with flex coil, according to an embodiment. 
     
    
    
     The same reference symbol used in various drawings indicates like elements. 
     DETAILED DESCRIPTION 
     Example Racetrack Coil Architecture 
       FIG. 1A  is a perspective view of a traditional racetrack coil actuator  100  that produces force (Lorentz force) in a portion of the coil. Actuator  100  includes coil  101 , North magnet  102  and South magnet  103 .  FIG. 1B  is a top view of architecture  100  showing the force direction.  FIG. 1C  is a side view of architecture  100 . In general, the force density of an electromagnetic motor at fixed power consumption is limited by the total cross-sectional area of the motor coils and the average intensity of the magnetic field incident normal to the direction of current in the coils. Note that the direction of the force arrows shown in  FIGS. 1B and 1C  indicate the direction of the force contribution. In actuator  100 , only the portions of coil  101  where the current flows orthogonal to the intended force direction contribute to the linear force. The other portions of coil  101  do not contribute to the linear force. 
     Example Double Helix Actuators 
       FIG. 2A  is a perspective view of a rectangular, double helix actuator  200 . Actuator  200  includes helix coil  201 , magnetic sections  202  polarized inward and magnetic sections  103  polarized outward.  FIG. 2B  is a top view of actuator  200  showing the force direction.  FIG. 2C  is a side view of actuator  200 . 
     As indicated by the direction of the force arrows, actuator  200  produces force in the force direction throughout the entirety of coil  201 . Accordingly, actuator  200  produces a greater linear force density compared to actuator  100 . Actuator  200  also produces torque in addition to linear force which presents an opportunity for unique haptic sensation in products, such as writing implements. Note that a single layer winding of the helical path contains not only a transverse field, but also an axial field component. The axial field is canceled by adding a second layer which has the opposite winding angle and an appropriate current direction so that the transverse fields of both layers add and the axial fields cancel. 
       FIG. 3A  is a perspective view of a cylindrical, double helix actuator  300 , according to an embodiment. Actuator  300  includes helix coil  301 , magnetic sections  302  polarized inward and magnetic sections  303  polarized outward.  FIG. 3B  is a top view of actuator  300  showing the force direction. Note that the directions of the force arrows shown in  FIG. 3B  indicate the directions of the force contributions. As indicated by the directions of the force arrows, actuator  300  produces force in the force direction throughout the entirety of coil  301 . 
       FIG. 4A  is a perspective view of an assembly of double helix actuator module  400 , according to an embodiment.  FIG. 4B  illustrates the components of module  400  shown in  FIG. 4A . Module  400  includes main assembly  401 , cover assembly  402 , inner assembly  403  and base assembly  404 . 
     Cover assembly  402  is a rectangular-shaped magnetic structure that includes top surface  405 , sides  406   a ,  406   b , and ends  407   a ,  407   b . Magnetic sections  408   a  (West and East magnets) of alternating polarity are arranged in a row and attached to side  406   a  of cover assembly  402 . Magnetic sections  408   b  (also West and East magnets) of alternating polarity are arranged in a second row and attached to side  406   b  of cover assembly  402 . As shown in  FIG. 4B , magnetic sections  408   a  and magnetic sections  408   b  are arranged such that magnets having the same polarity are opposite each other. For example, West magnets of magnetic sections  408   a  oppose West magnets of magnetic sections  408   b , and East magnets of magnetic sections  408   a  oppose East magnets of magnetic sections  408   b.    
     Magnetic sections  408   c  (South and North magnets) of alternating polarity are arranged in a row and attached to top surface  405  of cover assembly  402 . Magnetic sections  408   c  are disposed between magnetic sections  408   a ,  408   b , such that their magnetic field directions are orthogonal to magnetic field directions generated by magnetic sections  408   a ,  408   b . That is, the magnetic structure is designed to generate magnetic fields in West, East, North, and South directions. Magnetic sections  408   a - 408   c  are also arranged relative to each other such that when base assembly  404  is attached to cover assembly  402 , cavity  409  is formed. Cavity  409  encloses inner assembly  403 , which is disposed between mechanical linkages (not shown) attached to the cover assembly  402  (e.g., flexures, springs). 
     Main assembly  401  is configured to attach to cover assembly  402 . Main assembly  401  includes inner assembly  403  and base assembly  404 . Inner assembly  403  includes proof mass  410  and double helix coil  411  wound in two layers around proof mass  410 . As shown in the close-up view, the direction of coil  411  reverses at its end. When main assembly  401  is attached to cover assembly  402  and base assembly  404 , inner assembly  403  is disposed within cavity  409 , such that inner assembly  403  can move within cavity  409  in the force direction of actuator  400 . 
     Base assembly  404  includes base  412  and magnetic sections  408   d  of alternating polarity. Magnetic sections  408   d  are arranged in a row and attached to base  412  such that they are directly opposite to magnetic sections  408   c  of the same polarity when main assembly  401  is attached to cover assembly  402 . Spaces  413   a - 413   c  are reserved in module  400  for crash stops, to allow proof mass travel and for introducing displacement using flexures or springs. 
     In double helix actuator  400  described above, double helix coil  411  is wound in two layers around proof mass  410 , such that for each winding the magnetic field direction and coil current direction follow each other. In contrast to the traditional racetrack coil actuator, the double helix actuator  400  produces a linear force throughout the entirety of coil  411 . Also, the magnet and coil geometry of double helix actuator  400  results in a greater force density and motor efficiency within a fixed enclosure volume than the traditional racetrack coil architectures. Finally, the output of double helix actuator  400  contains multiple degrees of freedom, allowing double helix actuator  400  to be used in a variety of applications that are constrained in form factor and power, such as smartphones, smart watches, tablet computers, notebook computers, electronic pens/pencils and rotation piston applications (e.g., a dental drill, boring machines, etc.). 
     As used herein, the terms “coil” and “helix” include but are not limited to regular geometric patterns. In addition, the terms “coil” and “helix” include configurations wherein a width (e.g., along the axial direction) or a thickness (e.g., along a radial direction or transverse to the axial direction) may vary. Reference to a type of shape (e.g., rectangular, cylindrical) is not limited to a symmetrical or regular shape. Contemplated embodiments include variations which depart substantially from regular geometries. 
     With coils helically-wound about an axis to produce magnetic field components transverse to the axis, cancellation of axial field components can be effected by the formation of coils in concentrically positioned pairs having opposite winding angles, this sometimes resulting in a high quality transverse field. Generally, however, in embodiments having multiple pairs of coils with each coil helically-wound about an axis to produce transverse and axial magnetic field components, it is not necessary that members of pairs having opposite winding angles, to control or eliminate transverse axial components with respect to one another, be immediately next to one another in the sequence of coil rows. 
       FIG. 5A  is a side view of double helix actuator  400  shown in  FIGS. 4A and 4B  illustrating magnet orientation, according to an embodiment. Shown in  FIG. 5A  is a magnetic field pattern, coil current pattern and force pattern. As can be observed, the magnetic field orientation (shown by the direction of the arrows) and coil current follow each other, and the entire coil  411  contributes to the linear force. 
       FIG. 5B  is a bottom view of double helix actuator  400  illustrating magnetic field orientation due to magnetic sections  408   d , according to an embodiment. 
       FIG. 5C  is an end view of double helix actuator  400  illustrating magnetic field orientation due to magnetic sections  408   c , according to an embodiment. 
       FIG. 5D  is a blow-up view of inner assembly  403  of double helix actuator  400  illustrating a winding pattern for coil  411 , according to an embodiment. Note that coil  411  includes a first helix layer  411   a  that starts from end  415   a  of proof mass  410  and winds around the length of proof mass  410  in a helix pattern (similar to a barber shop pole) until end  415   b  is reached. At end  415   b , coil  411  winds around the length of proof mass  410  in the opposite direction to create second helix layer  411   b  that is disposed between gaps left by first helix layer  411   a.    
       FIG. 5E  is another perspective view of double helix actuator  400  illustrating magnetic field orientation, according to an embodiment. 
       FIG. 6A  is a side view of double helix actuator  400  illustrating current orientation, according to an embodiment.  FIG. 6B  is a bottom view of double helix actuator  400  illustrating current orientation, according to an embodiment.  FIG. 6C  is an end view of double helix actuator  400  illustrating current orientation, according to an embodiment. 
       FIG. 7A  is a side view of double helix actuator  400  illustrating coil force, according to an embodiment.  FIG. 7B  is a bottom view of double helix actuator  400  illustrating coil force, according to an embodiment.  FIG. 7C  is an end view of double helix actuator  400  illustrating coil force, according to an embodiment. 
       FIG. 8  illustrates force and torque production due to a helical winding angle, according to an embodiment. The force density {right arrow over (F)} is given by:
 
 {right arrow over (F)}={right arrow over (J)}×{right arrow over (B)},   [1]
 
where {right arrow over (J)}=I{right arrow over (A)}, I is the total current through the cross-section of the coil, {right arrow over (A)} is the cross-sectional area of the coil, and {right arrow over (B)} is the magnetic field vector. The direction of {right arrow over (A)} is perpendicular to the cross-section in the direction given by the loop right-hand-rule. In the example shown, {right arrow over (J)} and {right arrow over (B)} are assumed to be unit vectors, the winding angles are 13.45° in the x-y plane and 44.45° in the x-z plane, respectively. Vector values are shown for current, magnetic field and torque for turns 1-3 for coil layer  1  and turns 1-3 for coil layer  2 . As can be observed from  FIG. 8 , opposite z-oriented forces are produced on the left (−y) and right (+y) sides of the coil windings in addition to the x-oriented linear force, producing a torque. The torque can enable a unique haptic response for certain applications, such as a digital writing implements.
 
     Example Control Systems for Double Helix Actuators 
       FIG. 9  is a block diagram of an open loop control system  900  for the double helix actuator  400  shown in  FIGS. 1-8 , according to an embodiment. Control system  900  includes controller  901 , processor  902  and memory  903 . Controller can be configured to provide an actuator drive signal to control the motion of double helix actuator  400  (e.g., a haptic engine). Memory  903  includes core software instructions  904  executed by controller  901  and processor  902  to implement control of actuator  400 . Actuator  400  can be a moving coil type actuator or a moving magnet type actuator. 
     In a first embodiment of control system  900 , memory  903  includes core software instructions  904  to implement open loop control of actuator  400 . In a second embodiment of control system  900 , memory  903  includes core software instructions to implement velocity sensing, closed-loop control of actuator  400 . In the second embodiment, controller  901  receives back-electromotive force (EMF) voltage measurements at the coil terminals to be used by a closed-loop control law to generate and send control commands to double helix actuator  400 . In a third embodiment of control system  900 , memory  903  includes core software instructions  904  to implement position sensing closed-loop control of actuator  400 . In the third embodiment, controller  901  receives position data from one or more magnetic sensors (e.g., one or more Hall sensors), or a position indicating magnet located on the proof mass. If the actuator is a moving magnet type of actuator, then the magnetic sensors can be attached to the housing to measure the position of the drive magnets. In a fourth embodiment of control system  900 , memory  903  includes core software instructions to implement position and velocity sensing closed-loop control of actuator  400 . In this fourth embodiment, controller  901  receives back-EMF voltage measurements at the coil terminals and position data from one more magnetic sensors (e.g., Hall sensors) to be used by a closed-loop control law to generate and send control commands to double helix actuator  400 . 
     In an embodiment, an example closed-loop control system  900  suitable for controlling a double helix actuator in a haptic engine using back-EMF and Hall sensors is described in co-pending U.S. patent application Ser. No. 15/698,559 for “Closed-Loop Control of Linear Resonant Actuator Using Back-EMF data and Hall Sensing,” filed Sep. 7, 2017, which patent application is incorporated by reference herein in its entirety. 
     Example Cylindrical Double Helix Actuator 
       FIG. 10  illustrates a cylindrical double helix actuator with flex coil, according to an embodiment. The actuator can be assembled from  4  components: flexure caps  1001 , cylindrical housing  1002 , flex coil  1003  and helically magnetized core  1004 .  FIG. 3A  shows an assembled cylindrical double helix actuator. In the embodiment shown, flex coil process  1005  includes disposing a 4-period winding pattern  1007  on a rolled flex printed circuit board (PCB) to create flex coil  1003 . Winding pattern  1007  is an alternating solenoid, with alternating dipole polarization and continuous helical polarization. Winding pattern  1007  reverses direction every other period to eliminate torque and has a varying period length to linearize force. 
     Magnet design process  1008  includes progressively magnetizing AINiCo cylindrical core  1004  in a helical configuration and reversing the helical direction every other period to eliminate torque. In an embodiment, flexures  1009  are attached to flexure caps  1001 , and flexure caps  1001  are rotated 90 degrees relative to each other. Flexure caps  1001  are connected to AINiCo core  1004  by braizing. Alternately, spiral springs can be used instead of flexures  1009 . In an embodiment, the helical direction can be reversed so that the spring compression torque is opposite of the magnetic torque. In an embodiment, the helical direction can be followed so that spring compression torque is the same as the magnetic torque. 
     While this document contains many specific implementation details, these details should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can, in some cases, be excised from the combination, and the claimed combination may be directed to a sub combination or variation of a sub combination. Logic flows depicted in the figures do not require the particular order shown, or sequential order, to achieve desirable results. In addition, other steps may be provided, or steps may be eliminated, from the described flows, and other components may be added to, or removed from, the described systems. Accordingly, other implementations are within the scope of the following claims.

Metadata:
Filing Date: 20180521
Publication Date: 20220222
Grant Date: 20220222
Priority Date: 20180521
Inventors: HARRISON, JERE C.
SPELTZ, ALEX J.
WU, XIN ALICE
Assignee: APPLE INC
CPC Classifications: [{"code": "H02K41/03", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02K2201/18", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02K41/03", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02K35/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02K2201/18", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02K33/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02K33/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02K35/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02K2201/18", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02K41/03", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 68532883