Inductive encoder with shielding structure

Abstract

The present invention discloses an inductive encoder having a shielding structure, comprising: a scale including a periodic scale pattern; and a detector portion configured to move in a measurement axis direction with respect to the periodic scale pattern. The detector portion includes: a field generating portion configured to generate a varying magnetic flux; and a sensing portion comprising one or more sets of sensing elements and configured to provide detector signals responsive to local effects on the varying magnetic flux provided by the periodic scale pattern, where each set of sensing elements is coupled to a set of sensor vias. The detector portion further includes a plurality of shielding structures SST, where each shielding structure SST is positioned proximate to the set of sensor vias and includes a plurality of shielding vias, and in each shielding structure, one or more shielding loops are formed by the plurality of shielding vias coupled together by the conductor portion.

Description

Technical Field

[0001] The present disclosure relates to metrology, and more particularly, to inductive encoders. Background Art

[0002] Various position encoder configurations may include various types of inductive, optical, capacitive, magnetic, motion and / or position transducers. These position encoders use various geometric configurations (e.g., of a transmitter and a receiver) in a detector portion (e.g., as included in a read head) to measure movement between the detector portion and the scale.

[0003] As some examples of inductive encoders, U.S. Pat. Nos. 6,011,389 (the '389 patent) and 6,124,708 (the '708 patent) describe induced current position transducers that can be used for high accuracy applications; U.S. Pat. Nos. 5,973,494 (the '494 patent) and 6,002,250 (the '250 patent) describe incremental position inductive calipers and linear scales that include signal generation and processing circuits; and U.S. Pat. Nos. 5,886,519 (the '519 patent), 5,841,274 (the '274 patent), and 5,894,678 (the '678 patent) describe absolute position inductive calipers and electronic tape measures using induced current transducers. US Patent Nos. 10,520,335 (the '335 patent), 10,612,943 (the '943 patent), and 10,775,199 (the '199 patent) disclose improvements in winding configurations that can be used to enhance the accuracy, robustness, and ease of alignment of inductive encoders. All of the foregoing are incorporated herein by reference in their entirety.

[0004] As described in these patents, inductive encoders can be manufactured using printed circuit board (PCB) technology and are largely immune to contamination. However, such systems may be limited in their ability to provide certain combinations of features desired by users, such as a combination of consistency of measurement, high accuracy, high resolution, robustness to contamination, compact size, ease of use, low cost, etc. Configurations of inductive encoders that provide improved combinations of such features would be desirable. Summary of the invention

[0005] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0006] According to one aspect, an inductive encoder system configured to measure the relative position between two elements along a measuring axis direction is provided. The system includes: a scale extending along the measuring axis direction, the scale including a periodic scale pattern, the periodic scale pattern including a signal modulation element; and a detector portion, the detector portion being configured to be positioned adjacent to the periodic scale pattern and to move relative to the periodic scale pattern along the measuring axis direction. The detector portion: a field generating portion PRTFGE, the field generating portion PRTFGE being configured to generate a changing magnetic flux in response to a drive signal; and a sensing portion PRTSEN, the sensing portion PRTSEN including one or more sensing element sets arranged along the measuring axis direction. Each sensing element set is coupled to a sensor through-hole set, and the sensing portion PRTSEN is configured to provide detector signals, which respond to the local influence of the changing magnetic flux provided by the adjacent signal modulation elements of the periodic scale pattern. The detector portion also includes: a plurality of shielding structures SST, wherein each shielding structure SST is positioned adjacent to the sensor through-hole set. Each shielding structure SST includes a plurality of shielding vias, and in each shielding structure SST, one or more shielding loops are formed by the plurality of shielding vias coupled together by conductor portions.

[0007] In an exemplary implementation, the plurality of shielding structures SST are configured to at least partially shield the set of sensor vias from stray magnetic fields caused by the operation of the field generating portion PRTFGE. According to such exemplary implementations, the shielding of the set of sensor vias is technically advantageous in reducing offset signal portions in the detector signals that would otherwise be caused by the stray magnetic fields coupled to parasitic loops that may be formed by at least some of the sensor vias in the set of sensor vias.

[0008] According to another aspect, a method of operating the inductive encoder system configured to measure the relative position between two elements along a measuring axis direction is provided. The method generally includes three steps. The first step includes providing a drive signal that causes the field generating part PRTFGE to generate the changing magnetic flux, wherein the operation of the field generating part PRTFGE generates one or more stray magnetic fields. The second step includes receiving a detector signal from the sensing part PRTSEN, wherein at least one sensor through-hole set is at least partially shielded by the multiple shielding structures to be protected from the one or more stray magnetic fields. The third step includes determining the relative position between the detector part and the scale based at least in part on these detector signals.

[0009] According to another aspect, a detector portion used in an inductive encoder configured to measure the relative position between two elements along a measuring axis direction is provided. The encoder includes a scale extending along the measuring axis direction, the scale including a periodic scale pattern, and the periodic scale pattern including a signal modulation element. The detector portion is configured to be positioned adjacent to the periodic scale pattern and move relative to the periodic scale pattern along the measuring axis direction. The detector portion: a field generating portion PRTFGE, the field generating portion PRTFGE is configured to generate a changing magnetic flux in response to a drive signal; and a sensing portion PRTSEN, the sensing portion PRTSEN includes one or more sensing element sets arranged along the measuring axis direction. Each sensing element set is coupled to a plurality of sensor through holes, and the sensing portion PRTSEN is configured to provide detector signals, which respond to the local influence of the changing magnetic flux provided by the adjacent signal modulation elements of the periodic scale pattern. The detector portion also includes: a plurality of shielding structures SST, wherein each shielding structure SST is positioned adjacent to the sensor through hole set. Each shielding structure SST includes a plurality of shielding vias, and in each shielding structure SST, one or more shielding loops are formed by the plurality of shielding vias coupled together by conductor portions. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a block diagram of an inductive encoder system.

[0011] Figure 2 Such as can be Figure 1 Schematic diagram of a specific implementation of a converter including a detector portion and a scale utilized in an inductive encoder system.

[0012] Figure 3 is a diagram illustrating connections from a set of sensing elements of a detector portion to a set of sensor vias and to a processing portion, where these connections form a parasitic sensor loop.

[0013] Figure 4 is a collection of adjacent sensor vias such as Figure 3 and Figure 6 A diagram of a shielding structure SST with those sensor via set locations illustrated.

[0014] Figure 5 yes Figure 4 A diagram of a top view of a configuration of and further illustrating a stray magnetic field as generated by current passing through a field generating via.

[0015] Figure 6 Such as can be Figure 1An isometric view of a specific implementation of a transducer including a detector portion and a scale utilized in an inductive encoder system of the present invention and illustrating a field generating through hole and adjacent to a similar Figure 4 and Figure 5 Illustration of a shielding structure SST in which the sensor through-hole sets of those arrangements are positioned.

[0016] Figure 7 is a diagram of a cross-sectional portion of a printed circuit board (PCB) illustrating a detector portion including two shielded vias extending through six layers of the PCB.

[0017] Figure 8 is an example sensor through hole and Figure 6 0 is an isometric top view of a shielding structure SST, wherein shielding vias of the shielding structure SST are shown to be coupled together through a conductor portion (e.g., an upper conductor portion) that is part of a ground layer (e.g., layer L3) of a PCB.

[0018] Fig. 9 is an example Figure 8 An isometric bottom view of the configuration (e.g., viewed from below) Figure 8 FIG. 2 is a diagram of the same layer L3 of the PCB, wherein the shielding through holes of the shielding structure SST are shown to be coupled together also through a conductor portion (e.g., a lower conductor portion) in a layer of the PCB different from the ground layer L3 (e.g., layer L4, not shown), thereby forming a shielding loop in the shielding structure SST.

[0019] Fig.10 is a diagram illustrating two shielding structures SST each including four shielding vias arranged in a linear manner and located adjacent to and on opposite sides of a sensor via set including four sensor vias arranged in a linear manner.

[0020] Fig.11 is a diagram illustrating two shielding structures SST each including six shielding vias arranged in a linear manner and located adjacent to and on opposite sides of a sensor via set including six sensor vias arranged in a linear manner.

[0021] Fig.12 is an example of a Figures 4 to 6 Schematic diagram of a shielding structure SST with two box-shaped arrangements of sensor through-hole sets.

[0022] Fig.13 is a flow chart illustrating a routine for operating an inductive encoder system. DETAILED DESCRIPTION

[0023] Figure 11 is a block diagram of exemplary components of an inductive encoder system 100 including an inductive encoder 101. In various implementations, the inductive encoder 101 includes a scale 170 and a detector portion 167, which together form a converter TDR. The inductive encoder 101 includes suitable user interface features, such as a display 138 and / or user-operable control elements 136 (e.g., switches, buttons, etc.). In some implementations, the inductive encoder 101 can be used as part of a wireless-only device or other configuration (e.g., without the encoder 101 including a display). For example, the system 100 can be connected via or other connections to include a portion of a corresponding remote display, such as a phone or tablet. The encoder 101 may additionally include a power supply 165. All of these elements of the encoder 101 are coupled to a processing portion 166 (e.g., including one or more signal processors and, in some implementations, memory), which in various implementations may be embodied as signal processing and display electronics in an integrated circuit (IC) chip.

[0024] The processing portion 166 receives the detector signals from the detector portion 167 and processes the detector signals to determine the position of the detector portion 167 along the scale 170 (e.g., in some implementations, an absolute position). It should be understood that the processing portion 166 may include any combination of signal processing and physical circuitry. In various implementations, the processing portion 166 and the detector portion 167 may be included as part of the electronic assembly 160 (e.g., as disposed on a substrate, etc.). In various implementations, the control element 136, the display 138 and / or the power supply 165 may be included in the encoder 101 (and / or may be partially or completely included in a separate device or system (such as a host system or other device that may be part of the overall encoder system 100)).

[0025] It should be understood that such inductive encoders have been developed over the years to provide a relatively optimized combination of high resolution and high accuracy measurement, ease of use, compact size, low power operation, low cost, robustness to contamination, etc. Even small improvements in any of these factors are highly desirable, but difficult to achieve, especially in view of the design constraints imposed in order to achieve commercial success in various applications. The principles disclosed herein provide improvements in some of these factors for various applications.

[0026] It will be appreciated by those skilled in the art that the processing portion 166 and / or the detector portion 167 (and / or any other control system or control portion as described herein) may generally be implemented using any suitable computing device and / or system, including a distributed or networked computing environment, etc. Such computing devices and / or systems may include one or more general or special purpose processors (e.g., off-the-shelf devices or customized devices) that execute software to perform the functions described herein. The software may be stored in a memory (such as a random access memory (RAM), a read-only memory (ROM), a flash memory, etc., or a combination of such components). The software may also be stored in one or more storage devices (such as an optical-based disk, a flash memory device, or any other type of non-volatile storage medium for storing data). The software may include one or more program modules, which include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. In a distributed computing environment, the functionality of the program modules may be combined or distributed across multiple computing devices or systems, and the functionality of the program modules may be accessed via service calls in a wired or wireless configuration.

[0027] Figure 2 is a specific implementation of a converter TDR' comprising a detector portion 167' and a scale 170' (eg, it may be as described above with respect to Figure 1 160 ' includes a field generating part PRTFGE and a sensing part PRTSEN. Figure 2 In a simplified example, the detector portion 167' includes at least two substantially coplanar paths of wires or windings (PRTFGE and PRTSEN). The field generating portion PRTFGE includes a field generating winding (e.g., which may also be referred to as a transmitter winding or a transmitter coil in some specific implementations) that forms a large planar loop. In an exemplary specific implementation, the field generating winding defines (or surrounds) an internal area aligned with the periodic scale pattern 180 of the signal modulation element SME to generate a changing magnetic flux in the internal area in response to a field generating drive signal. The sensing portion PRTSEN includes a sensing element set SETSEN, which includes sensing elements SEN+ and SEN- formed by a sensing winding (e.g., which may also or alternatively be referred to as a receiver winding or a receiver coil in some specific implementations) in a substantially same plane or a very close parallel plane (e.g., such as on an adjacent or otherwise very close layer of a PCB) as the field generating winding of the field generating portion PRTFGE.

[0028] The sensing windings of the sensing portion PRTSEN are laid out in a zigzag or sinusoidal pattern in one direction as indicated by the arrows, and then in the opposite direction as indicated by the arrows, so that the windings cross themselves (e.g., with insulation at the intersections and / or on different PCB layers to avoid short circuits) to form alternating loops, which are designated as sensing elements SEN+ and SEN- inserted between each other, as shown. Therefore, each of the alternating loops of the sensing elements SEN+ and SEN- of the sensing element set SETSEN has a different winding direction compared to its adjacent loops. By applying an alternating (varying) current to the field generating portion PRTFGE, the field generating windings generate a time-varying magnetic field (changing magnetic flux) that extends through the loops of the sensing elements SEN+ and SEN- of the sensing element set SETSEN of the sensing portion PRTSEN.

[0029] The scale 170′ includes a periodic scale pattern 180 including signal modulating elements SME. In various implementations, the periodic scale pattern 180 has a spatial wavelength WSME and has a first type of signal modulating elements SME including similar conductive plates (e.g., Figure 2 ).

[0030] As a principle of operation, if the scale 170' comprising a scale periodic pattern 180 having signal modulation elements SME moves close to (adjacent to) the detector portion 167', the changing magnetic field generated by the field generating portion PRTFGE will induce eddy currents in the adjacent signal modulation element SME, which in turn establishes a magnetic field from the signal modulation element SME that cancels out the changing magnetic field (changing magnetic flux). As a result, the magnetic flux received by the sensing winding of the sensing portion PRTSEN is altered or interrupted, causing the sensing winding to output a non-zero electromagnetic field (EMF) signal (voltage) at the output terminals V+ and V- of the sensing winding of the sensing portion PRTSEN, which non-zero electromagnetic field (EMF) signal will increase or decrease and will change polarity when the signal modulation element SME moves between alignment with the "+" and "-" loops of the sensing elements SEN+ and SEN-, as will be described in more detail below.

[0031] The distance between the positions of two sensing elements of the same polarity (e.g., between the position of sensing element SEN+ to the position of the next sensing element SEN+) is defined as the pitch or wavelength WSEN of the sensing element set SETSEN of the sensing portion PRTSEN, and in some specific implementations may be equal to the pitch or wavelength WSME of the periodic scale pattern 180 of the scale 170'. It can be seen that each sensing element SEN+ and SEN- has a length or maximum dimension of 0.5*WSEN along the measuring axis direction MA. If the signal modulation element SME (e.g., a conductive plate) adjacent to the sensing portion PRTSEN continuously changes in position along the measuring axis direction MA, the alternating current (AC) amplitude of the signal output from the sensing portion PRTSEN will continuously and periodically change with the wavelength WSME due to the periodic modification of the sensing elements SEN+ and SEN- and the local interruption of the emitted magnetic field caused by the signal modulation element SME. Therefore, the signal output from the sensing portion PRTSEN can be used (e.g., processed) to indicate the relative position between the detector portion 167' and the scale 170'.

[0032] During operation, an alternating current may be provided, but in order to simplify certain portions of the description herein, only one current direction is described (e.g., for purposes of example of one current direction and / or as may occur in a configuration in which a diode or other component / configuration may be provided to limit current flow to one direction). As an example, current (e.g., as provided by a field generating drive signal such as from the processing portion 166 and / or controlled by the processing portion) may flow through the field generating winding of the field generating portion PRTFGE from terminal "IN" to terminal "OUT". More specifically, this indicates a current flow in a clockwise direction that generates a corresponding magnetic flux, for example, within an internal region aligned with the sensing portion PRTSEN. As noted above, such current flow (e.g., with a resulting magnetic flux as affected by the signal modulation element SME) results in a signal being generated in the sensing elements SEN+ and SEN- of the sensing portion PRTSEN.

[0033] As an example of how the inductive encoder 101 operates, as the scale 170' and its signal modulation element SME move relative to the detector portion 167' (e.g., such as corresponding to movement of the detector portion 167' relative to the scale 170', or vice versa), the signal modulation element SME alternately covers or is placed adjacent to all "+" loops of the sensing element SEN+ or all "-" loops of the sensing element SEN-. Figure 2In the indicated position, the signal modulation element SME is adjacent to all "-" loops of the sensing element SEN- in the sensing portion PRTSEN or "overlaps" (e.g., is aligned) with these loops. Since the field generating windings of the field generating portion PRTFGE are inductively coupled to the signal modulation element SME and induce eddy currents in the signal modulation element SME, the signal modulation element SME generates a magnetic field that cancels the magnetic field passing through the sensing element SEN-. Therefore, the sensing element SEN- generates less induced electromagnetic field (EMF) than the sensing element SEN+ that completely receives the flux from the magnetic field. Therefore, in this example, the sensing portion PRTSEN generates a net "positive" polarity EMF, current and / or voltage at its output. Because the field generating portion PRTFGE generates a time-varying magnetic field, the output signal varies with time. The time-varying output signal provides an indication of the position between the detector portion 167' and the scale 170' relative to the amplitude and polarity of the input signal.

[0034] Alternatively, when the scale 170' is moved (not shown) so that the signal modulation element SME overlaps (e.g., is aligned with) the "+" loop of the sensing element SEN+, the induced current generated in the signal modulation element SME cancels the flux of the magnetic field passing through the "+" loop of the sensing element SEN+. Therefore, the sensing element SEN- generates more induced EMF than the sensing element SEN+. Therefore, the sensing portion PRTSEN generates a net "negative" polarity EMF, current and / or voltage at its output terminal.

[0035] In one example, the circuitry of the processing portion 166 is coupled to the terminal V of the sensing portion PRTSEN. + and V - (eg, for receiving a detector signal), and samples changes in the signal output from the sensing portion PRTSEN (eg, voltage or current changes) and thereby calculates the linear position / distance of the detector portion 167' along the scale 170'. Figure 2For simplicity and to avoid visual confusion, a single set of sensing elements is shown, but in various implementations, the sensing portion PRTSEN includes one or more additional sets of sensing elements (e.g., similar to SETSEN as illustrated) located at different spatial phase positions (e.g., to provide orthogonal signals), as will be understood by one of ordinary skill in the art. In addition, in various implementations, one or more additional scale tracks (e.g., pattern portions) are included as part of the scale 170 along with one or more additional corresponding sets of sensing elements of the sensing portion PRTSEN. For example, in some implementations, the scale tracks may have a spatial phase offset relative to each other, or the wavelength of each scale track set may be different from the WSME and WSEN, for which combined processing of the signals may provide an absolute measurement result, etc. Certain examples of such principles are described in part in U.S. Patent Nos. 9,772,202 and 11,713,983, each of which is hereby incorporated by reference in its entirety.

[0036] It should also be understood that the configurations of the sensing elements described herein are intended to be exemplary only and not limiting. As an example, in some implementations, separate sensing element loops may output separate signals to corresponding processing portions, such as disclosed in U.S. Patent No. 9,958,294, which is hereby incorporated by reference in its entirety. More generally, in various implementations, various known sensing element configurations may be used in combination with the principles disclosed and claimed herein to be used in combination with various known scale patterns and signal processing schemes. With respect to such implementations, it should be understood that references herein to processing detector signals from the sensing portion PRTSEN of the detector portion 167 (e.g., for determining relative position) may include processing and / or combining signals from different sensing element sets SETSEN (e.g., orthogonal and / or from different scale tracks and / or as part of a three-phase or four-phase system, etc.).

[0037] The scale 170 and detector portion 167 and / or other elements as described herein can be readily manufactured by conventional techniques. For example, the detector portion 167 can be manufactured using known printed circuit board (PCB) techniques (on a rigid or flexible substrate) by forming a field generating portion PRTFGE and a sensing portion PRTSEN (e.g., including its windings) on a PCB substrate. Appropriate insulation and / or elements or portions of different elements on different layers of the PCB may be included at transition points between the “+” and “-” loops of the sensing elements SEN+ and SEN- where the sensing element set SESTSEN crosses itself, so as to prevent the windings from shorting at the transition points or intersections. Similarly, the scale 170 can be manufactured using known PCB techniques by forming a signal modulation element SME on a PCB substrate.

[0038] According to standard PCB manufacturing processes, "through holes" can be used for connections between different layers of a PCB (for example, through holes are sometimes also or alternatively referred to as "plated through holes" or "through vias" in PCBs for this purpose). Figure 2 As illustrated, there is a terminal V connected to the set of sensing elements SETSEN + and V - The two through holes SN+ and SN- of the sensing element set SETSEN are connected to the two through holes SN+ and SN- of the sensing element set SETSEN. The through holes SN+ and SN- are respectively referred to as "sensor through holes" in this document. The signal lines SIG+ and SIG- connect the terminals V + and V - to sensor vias SN+ and SN-, which are then externally connected to a processing portion 166 (which may, for example, include electronics located on a different layer of the PCB relative to the layer including the set of sensing elements SETSEN, and for which the sensor vias SN+ and SN- provide the necessary connections between the different layers of the PCB).

[0039] As will be described in more detail below, in various implementations, some of the connections from the set of sensing elements SETSEN to the processing portion 166, and in particular some of the connections to and from the sensor vias SN+ and SN-, may form a parasitic loop (e.g., a “parasitic sensor loop”). Figure 3 An example of such a parasitic sensor loop LSN-A is described in more detail. As will be described in more detail below, any current induced in such a parasitic sensor loop may result in an offset signal that introduces error into the position calculation / determination of the inductive encoder 101 .

[0040] More specifically, as noted above, for ideal inductive encoder operation, detector signals are generated based on the interaction of the signal modulation element SME of the scale 170 with a magnetic field / magnetic flux as generated by the field generating portion PRTFGE and as sensed by the sensing elements (e.g., as part of the set of sensing elements SETSEN, etc.). These signals, in turn, provide a highly accurate indication of the position of the detector portion 167 relative to the scale 170. However, if "stray magnetic fields" induce currents in parasitic sensor loops (e.g., as described above), this situation can result in offset signals in the detector signals as received by the processing portion 166, which can result in errors in the position calculation / determination of the inductive encoder 101. As will be described below (e.g., with respect to Figure 5 and Figure 6 ) is described in more detail, in some cases, such stray magnetic fields can be generated by the flow of current through "field generating vias" (i.e., vias used for connections between different layers of the PCB of the field generating portion PRTFGE). Figures 4 to 13 Further described in more detail, according to the principles disclosed herein, in order to reduce the impact of such problems, a shielding structure including a shielding via (e.g., which is used to form a shielding loop) is set to be positioned adjacent to the sensor via (e.g., to provide certain shielding effects, etc.).

[0041] Figure 3 is a diagram illustrating the connections from four sensing element sets SETSEN-A, SETSEN-B, SETSEN-C, and SETSEN-D to four sensor via sets SSN-A (including two sensor vias SN1A / SN2A), SSN-B (including two sensor vias SN1B / SN2B), SSN-C (including two sensor vias SN1C / SN2C), and SSN-D (including two sensor vias SN1D / SN2D). A larger sensor via set SSN-AB combines two sensor via sets SSN-A and SSN-B to include four sensor vias SN1A / SN2A and SN1B / SN2B. A larger sensor via set SSN-CD combines two sensor via sets SSN-C and SSN-D to include four sensor vias SN1C / SN2C and SN1D / SN2D. Signal lines SIG-A, SIG-B, SIG-C, and SIG-D carry corresponding signals from the set of sensing elements SETSEN-A, SETSEN-B, SETSEN-C, and SETSEN-D included in the sensor portion PRTSEN' to the four sensor via sets SSN-A, SSN-B, SSN-C, and SSN-D. Connections CON166 are signal lines from the four sensor via sets SSN-A, SSN-B, SSN-C, and SSN-D to a processing portion (e.g., processing portion 166), for which these connections may form parasitic loops (e.g., parasitic sensor loops).

[0042] Specifically, the connections CON166 to and from the sensor via sets SSN-A, SSN-B, SSN-C, and SSN-D to the processing portion 166 may form a parasitic sensor loop (e.g., where current may be induced by a "stray magnetic field," such as will be described in more detail below). As an example of such a parasitic sensor loop, the parasitic sensor loop LSN-A is comprised of Figure 2, where at least a portion of the interior of the parasitic sensor loop LSN-A is indicated by hatching. As illustrated, the parasitic sensor loop LSN-A includes at least a portion of a first sensor via set SSN-A (including two sensor vias SN1A and SN2A), such as a connection CON166 to the processing portion 166. Although only one parasitic sensor loop LSN-A is illustrated, it should be understood that additional parasitic sensor loops LSN-B, LSN-C, and LSN-D may be similarly formed based on the connections CON166 from other sensor via sets SSN-B, SSN-C, and SSN-D to the processing portion 166. Any current induced in such parasitic sensor loops LSN-A, etc. (e.g., as introduced by stray magnetic fields) may result in an offset signal that may introduce errors in the position calculation / determination of the inductive encoder 101. As will be described in more detail below, in order to address such issues, a shielding structure (e.g., which at least partially shields the sensor vias) may be provided to help prevent / reduce the induction of current in the parasitic sensor loop.

[0043] Figure 4 is an example of a proximity sensor via set SSN (e.g., such as Figure 3 and Figure 6 Schematic diagram of a shielding structure SST with an illustrated sensor through hole set (SSN) positioned. Figure 4 Three shielding structures SST-A, SST-B, and SST-C are illustrated that are positioned adjacent to sensor via sets SSN-A, SSN-B, SSN-C, and SSN-D and are configured to at least partially shield sensor vias SN included in those sensor via sets SSN-A, SSN-B, SSN-C, and SSN-D (e.g., at least partially shield the sensor vias from stray magnetic fields that could otherwise induce currents in parasitic sensor loops including the sensor vias). Each shielding structure SST includes a plurality of shielding vias SH, wherein in each shielding structure SST, one or more shielding loops SL are formed by the plurality of shielding vias SH coupled together by conductor portions CP such that current (e.g., eddy currents) can flow in a loop through each of the shielding loops SL (e.g., as part of a shielding function for effectively shielding the sensor vias).

[0044] Specifically, in Figure 4, a first shielding structure SST-A is positioned adjacent to a sensor via set SSN-AB and includes three shielding vias SH1A, SH2A, and SH3A for forming a first shielding loop SL1A and a second shielding loop SL2A. The first shielding loop SL1A is formed by shielding vias SH1A and SH2A coupled together by a first conductor portion CP1A (shown as a dotted line) near the top of the shielding vias SH1A and SH2A and a second conductor portion CP2A near the bottom of the shielding vias SH1A and SH2A. Thus, current can flow in the loop, such as illustrated by the current flow (arrow) CF1A through the first shielding loop SL1A. Similarly, the second shielding loop SL2A is formed by shielding vias SH2A and SH3A coupled together by a third conductor portion CP3A (shown as a dotted line) near the top of the shielding vias SH2A and SH3A and a fourth conductor portion CP4A near the bottom of the shielding vias SH2A and SH3A. Thus, current can flow in a loop, such as illustrated by current flow (arrow) CF2A through the second shielding loop SL2A. The first conductor portion CP1A and the third conductor portion CP3A (shown as dashed lines) may be formed in a ground layer or another layer of a PCB used to form the detector portion 167, as will be described in more detail below with reference to other figures. For simplicity of illustration, the ground layer (or other layers corresponding to the first conductor portion CP1A and the third conductor portion CP3A and other odd-numbered conductor portions indicated below) is not shown in FIG. Figure 4 Explicitly shown in Figure 8 and Fig. 9 Similar layers are represented in , as will be described in more detail below.

[0045] The second shielding structure SST-B is positioned adjacent to (and between) the sensor through hole set SSN-AB and the sensor through hole set SSN-CD, and includes two shielding through holes SH1B and SH2B for forming a shielding loop SL1B. The shielding loop SL1B is formed by the shielding through holes SH1B and SH2B coupled together by a fifth conductor portion CP1B (shown as a dotted line) near the top of the shielding through holes SH1B and SH2B and a sixth conductor portion CP2B near the bottom of the shielding through holes SH1B and SH2B. Therefore, current can flow in the loop to form a current flow (not shown) through the shielding loop SL1B. The fifth conductor portion CP1B (shown as a dotted line) can be formed in a ground layer or another layer of a PCB used to form the detector portion 167, as will be described in more detail below.

[0046] The third shielding structure SST-C is positioned adjacent to the sensor through hole set SSN-CD, and includes three shielding through holes SH1C, SH2C, and SH3C for forming a first shielding loop SL1C and a second shielding loop SL2C. The first shielding loop SL1C is formed by the shielding through holes SH1C and SH2C coupled together by the seventh conductor portion CP1C (shown as a dotted line) near the top of the shielding through holes SH1C and SH2C and the eighth conductor portion CP2C near the bottom of the shielding through holes SH1C and SH2C. Therefore, the current can flow in the loop to form a current flow through the first shielding loop SL1C. Similarly, the second shielding loop SL2C is formed by the shielding through holes SH2C and SH3C coupled together by the ninth conductor portion CP3C (shown as a dotted line) near the top of the shielding through holes SH2C and SH3C and the tenth conductor portion CP4C near the bottom of the shielding through holes SH2C and SH3C. Therefore, the current can flow in the loop to form a current flow through the second shielding loop SL2C. The seventh conductor portion CP1C and the ninth conductor portion CP3C (shown as dashed lines) may be formed in a ground layer or another layer of a PCB used to form the detector portion 167, as will be described in more detail below.

[0047] In various exemplary embodiments, stray magnetic fields (e.g., caused by vertical current flow in vertical field generating vias described in more detail below), if present, will induce eddy currents flowing in shield loops SL1A, SL2A, SL1B, SL1C, and SL2C of shield structures SST-A, SST-B, and SST-C. Such eddy currents will thus cancel the stray magnetic fields to prevent them from being undesirably coupled to parasitic sensor loops LSN-A, etc. (e.g., as part of a shielding function for at least partially shielding sensor vias that are part of the parasitic sensor loops).

[0048] Figure 5 yes Figure 4 The top view of the configuration and further illustrates as generated by passing through the field through hole FG1 (eg, as Figure 6 The current further illustrated) The stray magnetic field generated For example, the vertical current flows in the vertical field generating through hole FG1 provided in the detector portion 167. Undesirable generation of stray magnetic fields In the case of an unshielded SST structure, this stray magnetic field A certain amount of current will be undesirably induced in the parasitic loop LSN-A etc. formed in part by the sensor through hole set SSN, thereby causing an offset signal that introduces a position error. By positioning the shielding structure SST adjacent to the sensor through hole set SSN, eddy currents will flow in the shielding loop SL of the shielding structure SST to at least partially cancel stray fields, such as stray magnetic fields. This will desirably prevent / reduce stray fields from coupling to parasitic sensor loops LSN-A, etc., to thereby desirably reduce signal offsets and corresponding offset variability. In the illustrated example, a third shielding structure SST-C is shown shielding sensor via set SSN, specifically sensor via set SSN-D, from stray magnetic fields. The second shielding structure SST-B is also shown to shield the sensor via set SSN, specifically the sensor via set SSN-B, from stray magnetic fields. Influence.

[0049] In some implementations, at least some of the sensor through holes SN in the plurality of shielding structures SST-A, SST-B, and SST-C adjacent to the sensor through holes SN (e.g., sensor through holes SN in the set SSN-A, SSN-B, SSN-C, or SSN-D) are arranged linearly extending in a direction perpendicular to the measuring axis direction MA (e.g., a direction parallel to the x-axis direction) (e.g., a direction parallel to the y-axis direction). According to some implementations, the distance length DL2 of the linear arrangement of the shielding through holes of the shielding structure SST-A, SST-B, or SST-C is at least as long as the distance length DL1 of the linear arrangement of the sensor through holes in the SSN-A, SSN-B, SSN-C, or SSN-D adjacent to the shielding structure SST-A, SST-B, or SST-C.

[0050] In various specific implementations, it may be considered advantageous for the shielding structure SST to generally have more shielding through holes SH and more corresponding shielding loops SL rather than fewer shielding through holes SH and corresponding shielding loops SL (e.g., this may be more effective in shielding relative to the local strength of the magnetic field, and for this reason the total number may also be limited by certain practical considerations such as constraints / requirements of the PCB manufacturing process, etc.). For example, Figure 5 As illustrated, in the third shielding structure SST-C, the lower shielding via and the middle shielding via (eg, Figure 4 The first shielding loop SL1C formed by the upper shielding via and the middle shielding via (eg, SH1C and SH2C) is closer to the field generating via FG1 and is connected to the first shielding loop SL1C formed by the upper shielding via and the middle shielding via (eg, Figure 4 Compared with the second shielding loop SL2C formed by the SH3C and SH2C) which is farther away from the field generating through hole FG1, it can be affected by the magnetic field. Therefore, more current can be induced in the first shielding loop SL1C than in the second shielding loop SL2C, which can result in more effective shielding at a lower location relative to the local strength of the magnetic field at that location. In this example, compared to having only a single shielding loop (e.g., in which the shielding via SH2C is removed so that the upper and lower shielding vias (e.g., Figure 4 The first shielding loop SL1C may provide better / improved shielding compared to a configuration in which only one shielding loop is formed between SH3C and SH1C.

[0051] Figure 6 is a specific implementation of a converter TDR" comprising a detector portion 167" and a scale 170" (for example, it may be as described above with respect to Figure 1 160 and 161. An isometric view of a specific implementation of the converter TDR, detector portion 167 and scale 170 is shown. Figure 6 Also illustrated is a field generating via FG and a shielding structure SST (eg, in a similar manner to Figure 4 and Figure 5 of those arrangements). Figure 6 The configuration of the shielding structures SST-A, SST-B, SST-C positioned adjacent to the sensor through hole sets SSN-AB and SSN-CD is similar to Figure 4 and Figure 5 Those configurations, and therefore their detailed description will not be repeated.

[0052] It should be understood that certain aspects of the field generating elements (layers, etc.) and sensing elements (layers, etc.) of the detector portions (e.g., detector portion 167", etc.) as described herein may be based at least in part on the above description of the detector portions. Figure 2 To operate and understand the principles described. Figure 6 In a specific implementation of, the scale 170", the detector portion 167" and (e.g., Figure 1 ) processing portion 166 works cooperatively to provide an inductive encoder (e.g., inductive encoder 101) that can be used to measure the relative position between two elements (e.g., detector portion 167" and scale 170" and / or elements attached thereto) along a measuring axis direction MA.

[0053] In various specific implementations, the scale 170" extends along a measuring axis direction MA (e.g., corresponding to the x-axis direction) and includes a first signal modulation element SME1 and a second signal modulation element SME2. The first signal modulation element SME1 is arranged along the measuring axis direction MA according to a first scale pattern portion 180-1, and thus forms the first scale pattern portion. The second signal modulation element SME2 is arranged along the measuring axis direction MA according to a second scale pattern portion 180-2, and thus forms the second scale pattern portion. The first scale pattern portion 180-1 and the second scale pattern portion 180-2 are respective components of a periodic scale pattern 180" of the scale 170". In various specific implementations, the first signal modulation element SME1 and the second signal modulation element SME2 may have a spatial phase offset relative to each other, and in various specific implementations, may be arranged according to the same wavelength or different wavelengths (e.g., according to an expected interaction with a set of sensing elements of the sensing portion PRTSEN", as will be understood by those skilled in the art). In various specific implementations, the periodic scale pattern 180" may alternatively be referred to as a signal modulation pattern 180".

[0054] The relative movement between the detector portion 167″ and the scale 170″ indicates a relative position and / or measurement result (e.g., related to a physical element that can be coupled to the detector portion 167″ or the scale 170″, such as a first object or component and a second object or component for determining the relative position between the first object or component and the second object or component, or a first jaw and a second jaw (e.g., a caliper), or other measuring element between which an object can be placed for measuring a size of the object, etc.). The measured relative position or size can be displayed on a display (e.g., Figure 1 The inductive encoder may also include various known elements (e.g., physically fixed and / or moving elements, etc.) that are configured to guide movement of the detector portion 167" relative to the scale 170" (e.g., for sliding, etc.).

[0055] like Figure 6 As shown, the detector portion 167" may include a field generating portion PRTFGE" and a sensing portion PRTSEN" arranged along the measuring axis direction MA. Figure 6In the example of FIG. 1 , the sensing portion PRTSEN” includes four sensing element sets, each of which provides a detector signal on a corresponding signal line set including the illustrated signal line set SIG-A, SIG-B, SIG-C and SIG-D, which are coupled to corresponding sensor through-hole sets SSN-A, SSN-B, SSN-C and SSN-D. The signal lines SIG-A, SIG-B, SIG-C and SIG-D and the corresponding sensor through-hole sets SSN-A, SSN-B, SSN-C and SSN-D can be connected to Figures 3 to 5 The signal lines and sensor via sets illustrated are comparable and have similar connections to those.

[0056] Each signal line set SIG-A, SIG-B, SIG-C and SIG-D can also be connected to Figure 2 The illustrated sets of signal lines SIG+ and SIG- are comparable. For example, for a first set of sensing elements in the sensing portion PRTSEN", the corresponding signal line set SIG-A may include a SIG+ signal line and a SIG- signal line coupled to the V+ terminal and the V- terminal of the first set of sensing elements, respectively. Similarly, for a second set of sensing elements in the sensing portion PRTSEN", the corresponding signal line set SIG-B may include a SIG+ signal line and a SIG- signal line coupled to the V+ terminal and the V- terminal of the second set of sensing elements, respectively, and so on for a third set of sensing elements and a fourth set of sensing elements having corresponding signal line sets SIG-C and SIG-D. In various specific implementations, in the sensing portion PRTSEN", different sets of sensing elements may have a spatial phase offset relative to each other (for example, in an orthogonal arrangement and / or as a four-phase system, etc., as will be understood by those skilled in the art and as explained in more detail in the incorporated references).

[0057] In various specific implementations, such a configuration can enable determination of an absolute position (e.g., of a sensing portion PRTSEN″ of the detector portion 167″) relative to the scale 170″ along the measuring axis direction MA. Such a determination / calculation can be based on processing (e.g., by) detector signals provided by the detector portion 167″ (e.g., including detector signals provided by the sensing portion PRTSEN″ via a set of signal lines SIG-A, SIG-B, SIG-C, and SIG-D coupled to a set of sensor through-holes SSN-A, SSN-B, SSN-C, and SSN-D, which are coupled to / provide signals to the processing portion 166). Processing portion 166). As will be described in more detail below, according to the principles described herein, the shielding structure SST can be used to reduce the effects of stray magnetic fields (e.g., such as produced by the flow of current through field generating vias such as vias FG1-FG8) that could otherwise result in certain offset signals related to the detector signals from the sensing portion PRTSEN", which could otherwise result in certain errors in the position determination / calculation based on the detector signals from the sensing portion PRTSEN". The current flow through the field generating vias FG1-FG8 and the corresponding stray magnetic fields will be described in more detail below with respect to the operation of the field generating portion PRTFGE".

[0058] In various specific implementations, the field generating portion PRTFGE" may include several elongated portions FGE1-FGE4 and end portions ED1-ED4. The elongated portion FGE may extend approximately along the measuring axis direction MA (e.g., and correspondingly the x-axis direction) and is therefore parallel to the measuring axis direction MA, while the end portion ED may be approximately transverse (e.g., perpendicular) to the measuring axis direction MA (e.g., transverse to the x-axis direction so that the end portion ED may extend along the y-axis direction). The elongated portion FGE and the end portion ED in combination may form regions in which a changing magnetic flux may be generated by a current flow through the elongated portion FGE and the end portion ED caused by a drive signal, wherein these regions (e.g., inner regions) may include some of the sensing elements.

[0059] For example, in various embodiments, the field generating portion PRTFGE" may include elongated portions FGE1, FGE2, FGE3 and FGE4 and end portions ED1, ED2, ED3 and ED4 (for example, which in some embodiments may be viewed as forming two field generating element loops such as in an 8-shaped configuration and / or otherwise viewed as forming two loops in such a configuration so as to form a single field generating element loop with two internal regions). More specifically, the elongated portions FGE1 and FGE2 and the end portions ED1 and ED4 may be viewed as forming a first half loop having a first internal region, which is configured to be aligned with the first half pattern portion 180-1 of the periodic ruler pattern 180". The elongated portions FGE3 and FGE4 and the end portions ED2 and ED3 may be viewed as forming a second half loop having an internal region, which is configured to be aligned with the second half pattern portion 180-2 of the periodic ruler pattern 180".

[0060] exist Figure 6 In the example of , field generating vias FG1-FG8 provide connections between the elongated portion FGE and the end portion ED. In various specific implementations, the elongated portion FGE and the end portion ED may be included in different layers of a printed circuit board (PCB) and / or otherwise located at different vertical positions (e.g., in order to achieve certain desired operational properties, such as being closer to and having more interaction with the signal modulation element SME and the sensing element SEN than the magnetic field caused by the current flow through the elongated portion FGE than the magnetic field caused by the current flow through the end portion ED). The field generating vias FG provide connections between different layers / vertical positions.

[0061] exist Figure 6 In the example of FIG. 1 , end portion ED1 is coupled to elongated portions FGE1 and FGE2 through field generating vias FG2 and FG3, respectively. End portion ED2 is coupled to elongated portions FGE2 and FGE3 through field generating vias FG4 and FG5, respectively. End portion ED3 is coupled to elongated portions FGE3 and FGE4 through field generating vias FG6 and FG7, respectively. End portion ED4 is coupled to elongated portions FGE1 and FGE4 through field generating vias FG1 and FG8, respectively.

[0062] In various implementations, the end portion ED2 (e.g., or other portions of the field generating portion PRTFGE') can be represented as including the port PT1 or other connection configurations. For example, the end portion ED2 can be divided into two components, such as having two contact points disposed in the port PT1 for the field generating portion PRTFGE', as shown in FIG. Figure 6As illustrated. The contact points in port PT1 can be used to receive drive signals and can be located at locations where signal lines / circuit traces from the processing portion 166 can be connected, etc. In various specific implementations, port PT1 can represent a general connection configuration such as coupled to field generating drive electronics (for example, such as between field generating vias FG4 and FG5). In various specific implementations, such field generating drive electronics may include electronic components such as capacitors, transistors, etc. and such as may be at least partially or completely included in the processing portion 166 or coupled to the processing portion for providing a drive signal for causing the field generating portion PRTFGE" to generate a varying magnetic flux. As described herein (for example, with respect to Figure 5 ) as described above, the corresponding current flow through the field generating portion PRTFGE" includes current flow through the field generating vias FG1-FG8 (e.g., such as vertical current flow ), these current flows can generate stray magnetic fields (e.g., such as stray magnetic fields ), for which reason the shielding structure SST as described herein is intended to reduce the undesired effects of such stray magnetic fields on the detector / measurement signals of the inductive encoder.

[0063] Signal lines / circuit traces from the processing portion 166 are connected (not shown) to the field generating portion PRTFGE" (e.g., for providing a drive signal). During operation, an alternating current may be provided, but to simplify the following description, only one current direction is described (e.g., for purposes of example in one direction and / or as may occur in a configuration in which a diode or other component / configuration may be provided to limit current flow to one direction). As an example, current (e.g., as provided by a drive signal) may flow through the following sequence of portions (e.g., in the following order for current in one direction), including: field generating via FG1; elongated portion FGE1; field generating via FG2; end portion ED1; field generating via FG3; elongated portion F GE2; field generating via FG4; end portion ED2; field generating via FG5; elongated portion FGE3; field generating via FG6; end portion ED3; field generating via FG7; elongated portion FGE4; field generating via FG8; and end portion ED4. Based on this example of current flow, it should be understood that current flows in the same direction (e.g., in a first direction along the x-axis / measurement axis direction MA) through the elongated portions at the outer boundaries of the configuration (i.e., elongated portions FGE1 and FGE3), and in the same direction (e.g., in a second direction opposite to the first direction along the x-axis / measurement axis direction MA) through the elongated portions in the middle of the configuration (i.e., elongated portions FGE2 and FGE4), as may be desired in certain implementations.

[0064] In various embodiments, the detector portion 167" is configured to be mounted adjacent to a periodic scale pattern 180" of the scale 170", and to move relative to the periodic scale pattern 180" of the scale 170" along the measuring axis direction MA. In various embodiments, the field generating portion PRTFGE" and the sensing portion PRTSEN" of the detector portion 167" may be formed according to a variety of alternative configurations to be used in combination with a variety of corresponding signal processing schemes, as will be understood by those skilled in the art.

[0065] It should be understood that various elements may reside on different manufacturing layers positioned at different planes along the z-axis direction, as needed to provide various operating gaps and / or insulating layers, as will be readily apparent to one of ordinary skill in the art based on the description herein and the incorporated references. Throughout the drawings of the present disclosure, it should be understood that the illustrated x-axis, y-axis, and / or z-axis dimensions of one or more elements may be exaggerated for clarity, and it should be understood that these dimensions are not intended to contradict the various design principles and relationships discussed herein.

[0066] Figure 7 is a diagram illustrating a cross-sectional portion of a printed circuit board (PCB) including two shielding vias SH1A and SH2A extending through six layers of the PCB. In various implementations, the illustrated portion may be part of an overall PCB that may be referred to as a “detector substrate” on which a detector portion (e.g., Figure 6 Detector portion 167"). Figure 7 As illustrated, the PCB includes six layers L1-L6, wherein each of the labeled layers L1-L6 is an electrical layer, and the layers between the labeled electrical layers L1-L6 are insulating layers. It should be understood that this configuration is intended to be merely illustrative.

[0067] In various implementations, layers L1 and L2 include an electronics layer and a wiring layer, respectively, and may include at least a portion of a processing portion, which may be processing portion 166 ( Figure 1 ) and / or may be otherwise coupled to the processing portion and / or help provide and / or process drive signals to the field generating portion PRTFGE" and / or detector signals from the sensing portion PRTSEN", etc. Layer L3 includes a ground layer (GND) (e.g., for providing ground and / or other common connections, etc.). Layer L4 includes a field generating element layer, which may include a field generating portion (e.g., Figure 6 Layers L5 and L6 include sensing element layers, which may include sensing portions (e.g., Figure 6In various implementations, layers L5 and L6 may include most or all of the set of sensing elements of the sensing portion PRTSEN", with different traces on different layers L5 and L6 (e.g., to electrically isolate at intersections, etc.), and wherein the connection between layers L5 and L6 for the sensing elements may be achieved by certain types of through-holes (e.g., such as micro-vias extending only between layers L5 and L6, and in some implementations, these through-holes may also or alternatively be referred to as blind through-holes and / or buried through-holes).

[0068] As noted above, Figure 7 The specific view of exemplifies two shielding through holes SH1A and SH2A extending through six layers L1-L6 of the PCB. According to certain standard processes, the through holes can be made by drilling holes through the layers of the printed circuit board with a mechanical drill and then plating the holes (e.g., with copper) to form through holes. According to certain design rules of the PCB, through holes, traces and / or other components or elements must have certain spacing between them, as well as other restrictions on certain types of geometric relationships, etc. It is noted that the shielding structure SST with shielding through holes SH as disclosed herein can be formed according to such standard processes.

[0069] Unlike more typical vias (e.g., such as sensor vias SN and field generating vias FG) that are connected to other electronic circuits (e.g., to processing portion 166), in various implementations, shield vias SH and corresponding shield structures SST as described herein are independent elements that are self-contained and not connected to other electronic circuits or otherwise part of the connectivity for signals to or from other electronic circuits (e.g., such as to or from processing portion 166). In one example, if shield vias SH1A and SH2A are each coupled to a conductor portion CP1A (see Figure 4 ) (eg, to layer L3 (GND)), and are each coupled to a lower conductor portion CP2A (see Figure 4 ) of layer L4, a corresponding shielding loop SL1A is formed, wherein current can flow (e.g., in one specific example direction) upward along the shielding via SH1A, across layer L3, downward along the shielding via SH2A and across layer L4. Generally speaking, the conductor portion CP for coupling the shielding vias SH to each other is included in a specific layer of the PCB, such as the following Figure 8 and Fig. 9 Further illustrated.

[0070] In various implementations, it may be desirable for the shielding loop SL to span at least between layers L3 and L4. More specifically, in some implementations, the distance between layers L3 and L4 may be relatively large (e.g., approximately 1.0 mm), while the distance between layers L1 and L3 or between layers L4 and L6 may be relatively small (e.g., approximately 0.1 mm, for which example, as noted above, Figure 7 The z-axis dimensions of some of the illustrated corresponding layers (such as between L1 and L3 and between L4 and L6) have been enlarged to more clearly illustrate the corresponding layers. In such examples, the relative distance (e.g., along the z-axis) between layers L3 and L4 (e.g., approximately 1.0 mm) may be greater than 10 times the relative distance between layers L1 and L2, or L2 and L3, or L4 and L5, or L5 and L6. In certain implementations, where a parasitic loop (e.g., LSN-A) includes a connection between layer L1 and layer L5 or L6 and thus spans more than the distance between layers L3 and L4, it may be desirable for the shielding loop SL to span at least the large distance between layers L3 and L4 in order to effectively shield at least a majority of the area of ​​the parasitic loop. As a specific example, when connecting shielding via SH1A to shielding via SH2A, if layer L3 (or L1 or L2) is selected to form upper conductor portion CP1A, it may be desirable for the lower conductor portion to be at least in layer L4 (or L5 or L6).

[0071] Figure 8 are example sensor via sets SSN-AB and SSN-CD and Figure 6 Schematic diagram of an isometric top view of a shielding structure SST, wherein the shielding vias SH of the shielding structure SST are shown to be coupled together through a conductor portion CP (e.g., an upper conductor portion) that is part of a ground layer (e.g., layer L3 (GND)) of a PCB. Specifically, in the illustrated example, the upper conductor portion CP1A that couples the shielding via SH1A to the shielding via SH2A in the first shielding structure SST-A, the upper conductor portion CP3A that couples the shielding via SH2A to the shielding via SH3A in the first shielding structure SST-A, the upper conductor portion CP1B that couples the shielding via SH1B to the shielding via SH2B in the second shielding structure SST-B, the upper portion CP1C that couples the shielding via SH1C to the shielding via SH2C in the third shielding structure SST-C, and the upper portion CP3C that couples the shielding via SH2C to the shielding via SH3C in the third shielding structure SST-C are all formed in the ground layer L3 (GND). In this example, technically all shielding vias SH are coupled together on one side through layer L3 (e.g., ground layer L3), and on the other side through a conductor portion in another layer (e.g., layer 4) to complete the shielding loop SL, as shown in FIG. Fig. 9 Will exemplify.

[0072] Fig. 9 is an example Figure 8 An isometric bottom view of the configuration (e.g., viewed from below) Figure 8 3 (GND) of the same layer L3 (GND) of the PCB), wherein the shielding through holes SH of the shielding structure SST are shown to be coupled together through a conductor portion CP (e.g., a lower conductor portion) in a layer different from the ground layer L3 (e.g., in layer L4) of the PCB, thereby forming a shielding loop SL in the shielding structure SST. Specifically, for each shielding structure SST-A, SST-B or SST-C, the plurality of shielding through holes include at least a first shielding through hole SH (e.g., SH1A) and a second shielding through hole SH (e.g., SH2A), the first shielding through hole SH and the second shielding through hole SH are coupled together through the first conductor portion CP (e.g., Figure 8 The upper conductor portion CP1A of the embodiment is coupled together and connected to the upper conductor portion CP1A of the embodiment of the present invention through the second conductor portion (for example, Fig. 9 Thus, the first shielding via (e.g., SH1A), the first conductor portion (e.g., CP1A), the second shielding via (e.g., SH2A), and the second conductor portion (e.g., CP2A) form one or more shielding loops (e.g., Figure 4 Similarly, lower conductor portions CP4A, CP2B, CP2C, and CP4C may be formed in layer L4 to complete other shielding loops SL2A, SL1B, SL1C, and SL2C, respectively.

[0073] Fig. 9 The (lower) conductor portions CP2A, CP4A, CP2B, CP2C and CP4C shown as being disposed in layer L4 may also or alternatively be referred to as “conductor strips”. In alternative implementations, assuming that the other (upper) conductor portions CP1A, CP3A, CP1B, CP1C and CP3C of all shielding vias SH are included in one of the layers L1, L2 or L3 (e.g., in the upper portion of the PCB as described above), the conductor portions CP2A, CP4A, CP2B, CP2C and CP4C may be included in one of the other layers L5 or L6 (e.g., in the lower portion of the PCB). In various implementations, the (upper) conductor portions CP1A, CP3A, CP1B, CP1C and CP3C may also be formed as “conductor strips” (e.g., as included in one of the layers L1 or L2, and in this case, all shielding vias SH will not be coupled together on one side by a layer such as the ground layer L3).

[0074] Fig.10 is an example of each including a linear arrangement (for example, along Fig.10FIG. 1 is a diagram of a sensor through hole set SSN having four shielding through holes SH disposed in the y-axis direction in FIG. 1 and two shielding structures SST-A′ and SST-B′ located adjacent to and on opposite sides of a sensor through hole set SSN′. In the illustrated example, the sensor through hole set SSN′ includes: a first sensor through hole set SSN-A′ including two sensor through holes and a second sensor through hole set SSN-B′ also including two sensor through holes, and a signal line SIG′ carries a signal from a corresponding sensing element set (not shown) to the first sensor through hole set and the second sensor through hole set.

[0075] Because in the illustrated example, each shielding structure SST' has four shielding through holes SH, each shielding structure SST' may form at least three shielding loops SL. Specifically, in the first shielding structure SST-A', the first shielding through hole SH1A and the second shielding through hole SH2A may be coupled together through the first conductor part CP1A and the second conductor part CP2A to form the first shielding loop SL1A, the second shielding through hole SH2A and the third shielding through hole SH3A may be coupled together through the third conductor part CP3A and the fourth conductor part CP4A to form the second shielding loop SL2A, and the third shielding through hole SH3A and the fourth shielding through hole SH4A may be coupled together through the fifth conductor part CP5A and the sixth conductor part CP6A to form the third shielding loop SL3A. Similarly, in the second shielding structure SST-B', the first shielding through hole SH1B and the second shielding through hole SH2B can be coupled together through the first conductor part CP1B and the second conductor part CP2B to form a first shielding loop SL1B, the second shielding through hole SH2B and the third shielding through hole SH3B can be coupled together through the third conductor part CP3B and the fourth conductor part CP4B to form a second shielding loop SL2B, and the third shielding through hole SH3B and the fourth shielding through hole SH4B can be coupled together through the fifth conductor part CP5B and the sixth conductor part CP6B to form a third shielding loop SL3B.

[0076] like Fig.10 As illustrated, at least some of the sensor through holes in the set of sensor through holes to which the plurality of shielding structures SST-A' and SST-B' are positioned adjacent (e.g., the sensor through holes in the set SSN-A' and SSN-B') are arranged linearly extending in a direction perpendicular to the measuring axis direction MA (e.g., the direction parallel to the x-axis direction) (e.g., the direction parallel to the y-axis direction). According to certain specific implementations, the distance length (e.g., DL2) of the linear arrangement of the shielding through holes SH of the shielding structure SST (e.g., SST-A', SST-B') is at least as long as the distance length (DL1) of the linear arrangement of the sensor through holes (e.g., the sensor through holes in SSN') adjacent to the shielding structure (e.g., SST-A' or SST-B'). Fig.10 In the specific example of , DL2 may be approximately equal to DL1, and below Fig.11 A similar size ratio (with approximately equal distance lengths) is shown in .

[0077] Fig.11 2 is a diagram illustrating two shielding structures SST-A" and SST-B", each including six shielding through holes SH arranged linearly (e.g., along the y-axis direction). The two shielding structures SST-A" and SST-B" are positioned adjacent to and on opposite sides of a sensor through hole set SSN" including six sensor through holes arranged linearly, and a signal line SIG" carries a signal from a corresponding sensing element set (not shown) to the sensor through hole set.

[0078] Because in this example, each shielding structure SST" includes six shielding through holes SH1-SH6, each structure SST" may form at least five shielding loops SL. Specifically, in the first shielding structure SST-A", the first shielding through hole SH1A and the second shielding through hole SH2A can be coupled together through the upper conductor part CP and the lower conductor part CP to form a first shielding loop SL1A, the second shielding through hole SH2A and the third shielding through hole SH3A can be coupled together through the upper conductor part CP and the lower conductor part CP to form a second shielding loop SL2A, the third shielding through hole SH3A and the fourth shielding through hole SH4A can be coupled together through the upper conductor part CP and the lower conductor part CP to form a third shielding loop SL3A, the fourth shielding through hole SH4A and the fifth shielding through hole SH5A can be coupled together through the upper conductor part CP and the lower conductor part CP to form a fourth shielding loop SL4A, and the fifth shielding through hole SH5A and the sixth shielding through hole SH6A can be coupled together through the upper conductor part CP and the lower conductor part CP to form a fifth shielding loop SL5A. Similarly, in the second shielding structure SST-B", the first shielding through hole SH1B and the second shielding through hole SH2B can be coupled together through the upper conductor portion CP and the lower conductor portion CP to form a first shielding loop SL1B, the second shielding through hole SH2B and the third shielding through hole SH3B can be coupled together through the upper conductor portion CP and the lower conductor portion CP to form a second shielding loop SL2B, the third shielding through hole SH3B and the fourth shielding through hole SH4B can be coupled together through the upper conductor portion CP and the lower conductor portion CP to form a third shielding loop SL3B, the fourth shielding through hole SH4B and the fifth shielding through hole SH5B can be coupled together through the upper conductor portion CP and the lower conductor portion CP to form a fourth shielding loop SL4B, and the fifth shielding through hole SH5B and the sixth shielding through hole SH6B can be coupled together through the upper conductor portion CP and the lower conductor portion CP to form a fifth shielding loop SL5B.

[0079] Fig.12 is a diagram illustrating two shielding structures SST"' arranged in a box shape, each shielding structure surrounding a similar Figures 4 to 6 Those arrangements of the sensor through hole set SSN. Specifically, the first box-shaped arrangement SST-AB"' is formed by: a first shielding structure SST-A"', in which two shielding through holes SH1A and SH2A are coupled together through an upper conductor portion CP1A"' and a lower conductor portion CP2A"' to form a first shielding loop SL1A (for example, parallel to the YZ plane of the coordinate system) with a current loop CL1A; and a second shielding structure SST-B"', in which two shielding through holes SH1B and SH2B are coupled together through an upper conductor portion CP1B"' and a lower conductor portion CP2B"' to form a first shielding loop SL1A with a current loop CL1A. A second shielding loop SL1B having a current loop CL1B is formed (e.g., parallel to the YZ plane). In addition, in the first box-shaped arrangement SST-AB"', the first shielding structure SST-A"' and the second shielding structure SST-B"' are coupled together through the upper conductor portions CP1AB"' and CP3AB"' and the lower conductor portions CP2AB"' and CP4AB"' to form a third shielding loop SL1AB and a fourth shielding loop SL2AB having current loops CL1AB and CL2AB (e.g., parallel to the XZ plane).

[0080] In some implementations, shielding currents flowing in the XZ plane (eg, through current loops CL1AB and CL2AB) can distort the magnetic field through scale 170 in the XY plane (eg, according to Figure 2 and Figure 6 ') to change the quality / accuracy of the detector signal, in which case the box-like arrangement SST-AB"' may be considered less desirable than other configurations of the shielding structure SST described above. Alternatively, in certain embodiments, it may be desirable to allow the shielding current to flow in the XZ plane (e.g., through current loops CL1AB and CL2AB), for which purpose the box-like arrangement SST-AB"' may be considered more desirable.

[0081] Similar to the first box-shaped arrangement SST-AB"', the second box-shaped arrangement SST-CD"' is formed by: a first shielding structure SST-C"', in which two shielding through holes SH1C and SH2C are coupled together through an upper conductor portion CP1C"' and a lower conductor portion CP2C"' to form a first shielding loop SL1C having a current loop CL1C (for example, parallel to the YZ plane of the coordinate system); and a second shielding structure SST-D"', in which two shielding through holes SH1D and SH2D are coupled together through an upper conductor portion CP1D"' and a lower conductor portion CP2D"' to form a second shielding loop SL1D having a current loop CL1D (for example, parallel to the YZ plane). In addition, in the second box-shaped arrangement SST-CD"', the first shielding structure SST-C"' and the second shielding structure SST-D"' are coupled together through the upper conductor portions CP1CD"' and CP3CD"' and the lower conductor portions CP2CD"' and CP4CD"' to form a third shielding loop SL1CD and a fourth shielding loop SL2CD (for example, parallel to the XZ plane) having current loops CL1CD and CL2CD.

[0082] Utilizing the first box-shaped arrangement SST-AB"' and the second box-shaped arrangement SST-CD"', the shielding current may additionally flow in the XY plane, for example, through the upper conductor portions CP1A"', CP1AB"', CP1B"' and CP3AB"', or through the lower conductor portions CP2A"', CP2AB"', CP2B"' and CP4AB"', or through the upper conductor portions CP1C"', CP1CD"', CP1D"' and CP3CD"', or through the lower conductor portions CP2C"', CP2CD"', CP2D"' and CP4CD"'. Similar to the potential current flowing in the XZ plane, in various embodiments, the potential current flowing in the XY plane may be considered more desirable or less desirable.

[0083] Fig.13 13 is a flow chart illustrating a routine 1300 for operating an inductive encoder system that may be configured as described in detail above. The method generally includes three steps. In box 1310, the first step includes providing a drive signal that causes a field generating portion PRTFGE of a detector portion 167 of the inductive encoder 101 to generate a varying magnetic flux. The operation of the field generating portion PRTFGE generates one or more stray magnetic fields, and the detector portion 167 includes a sensing portion PRTSEN, which includes one or more sensing element sets SETSEN arranged along a measuring axis direction MA. Each sensing element set SETSEN is coupled to a set of sensor through holes SN, and the detector portion 167 is configured to move along the measuring axis direction MA relative to a scale 170 including a signal modulation element SME.

[0084] In block 1320, a second step includes receiving a detector signal from a sensing portion PRTSEN, wherein at least one set of sensor vias SN is at least partially shielded by a plurality of shielding structures SST from one or more stray magnetic fields. For example, at least some of the sensor vias SN in the at least one set of sensor vias SSN form at least a portion of one or more parasitic loops, and the shielding of the at least one set of sensor vias SSN reduces an offset signal portion in the detector signal that would otherwise be caused by one or more stray magnetic fields coupled to the one or more parasitic loops in the absence of the shielding structures SST.

[0085] In block 1330, a third step includes determining a relative position between the detector portion 167 and the scale 170 based at least in part on the detector signal. To this end, the plurality of shielding structures SST may be configured to prevent the determined relative position from including at least a portion of a position error that would otherwise be caused by an offset signal portion that would be produced if the shielding structures SST were not present.

[0086] It should be understood that the principles disclosed and claimed herein can be easily and desirably combined with the various features disclosed in the incorporated references. The above-mentioned various embodiments can be combined to provide additional embodiments. All U.S. patents and U.S. patent applications mentioned in this specification are incorporated herein by reference in their entirety. If it is necessary to adopt the concepts of various patents and applications to provide additional embodiments, the various aspects of the embodiments can be modified. These and other changes can be made to the embodiments according to the detailed description above. In general, in the following claims, the terms used should not be interpreted as limiting the claims to the specific embodiments disclosed in this specification and the claims, but should be interpreted as including all possible embodiments and the full range of equivalents given by these claims.

Claims

1. An inductive encoder system configured to measure the relative position between two elements along a measuring axis, the system comprising: a scale extending along the measurement axis direction, the scale comprising a periodic scale pattern, the periodic scale pattern comprising a signal modulation element; a detector portion, the detector portion being configured to be positioned adjacent to the periodic scale pattern and to move relative to the periodic scale pattern along the measurement axis direction, the detector portion comprising: a field generating portion PRTFGE configured to generate a varying magnetic flux in response to a drive signal; and a sensing portion PRTSEN comprising one or more sets of sensing elements arranged along the measuring axis direction, wherein each set of sensing elements is coupled to a set of sensor vias, and the sensing portion PRTSEN is configured to provide a detector signal responsive to a local influence on the varying magnetic flux provided by adjacent signal modulating elements of the periodic scale pattern; and A plurality of shielding structures SST, wherein each shielding structure SST is positioned adjacent to the set of sensor vias and includes a plurality of shielding vias, and in each shielding structure SST, one or more shielding loops are formed by the plurality of shielding vias coupled together by conductor portions.

2. The system according to claim 1, wherein for each shielding structure SST, the plurality of shielding vias include at least a first shielding via and a second shielding via, the first shielding via and the second shielding via being coupled together by a first conductor portion and coupled together by a second conductor portion, and the first shielding via, the first conductor portion, the second shielding via and the second conductor portion form a first corresponding shielding loop among the one or more shielding loops.

3. The system according to claim 2, wherein for one or more shielding structures SST among the multiple shielding structures SST, the multiple shielding vias include at least a third corresponding shielding via, which is coupled to the second shielding via through a third conductor portion and coupled to the second shielding via through a fourth conductor portion, and the second shielding via, the third conductor portion, the third shielding via and the fourth conductor portion form a second corresponding shielding loop among the one or more shielding loops. 4 . The system of claim 3 , wherein for each shielding structure SST, the plurality of shielding vias are arranged linearly.

5. The system of claim 2, wherein the first conductor portion is located in a first layer of a printed circuit board and the second conductor portion is located in a second layer of the printed circuit board. 6 . The system of claim 1 , wherein the plurality of shielding structures (SST) include at least a first shielding structure and a second shielding structure. 7 . The system of claim 6 , wherein the first shield structure (SST) and the second shield structure (SST) are positioned on opposite sides of a sensor via set including at least two sensor vias. 8 . The system of claim 6 , wherein the first shield structure (SST) and the second shield structure (SST) are positioned on opposite sides of a sensor via set comprising at least four sensor vias.

9. The system of claim 1, wherein the plurality of shielding vias are configured to at least partially shield the sensor vias from one or more magnetic fields caused by current flowing in one or more field generating vias.

10. The system of claim 1, wherein each shielding structure SST comprises the plurality of respective shielding vias in a linear arrangement extending in a direction perpendicular to the measuring axis direction.

11. The system of claim 10, wherein at least some of the sensor through-holes in the set of sensor through-holes adjacent to which the plurality of shielding structures SST are positioned are in a linear arrangement extending in a direction perpendicular to the measurement axis direction. 12 . The system of claim 11 , wherein a distance length of a linear arrangement of shield vias of a first shield structure SST is at least as long as a distance length of a linear arrangement of sensor vias adjacent to the first shield structure SST.

13. A system according to claim 1, wherein the field generating portion PRTFGE includes one or more field generating elements surrounding an inner region, the inner region being aligned with at least a portion of the periodic scale pattern of the signal modulation element during operation, wherein the one or more field generating elements are configured to generate the changing magnetic flux in the inner region in response to the drive signal.

14. The system of claim 13, wherein each shielding structure SST is configured to at least partially shield an adjacent set of sensor vias from stray magnetic fields caused by the operation of the field generating portion PRTFGE.

15. The system of claim 1, wherein the member of the sensing element assembly comprises a loop.

16. The system of claim 1, wherein the one or more sets of sensing elements include at least a first set of sensing elements and at least one additional set of sensing elements, wherein each additional set of sensing elements has a spatial phase offset relative to the first set of sensing elements.

17. A method of operating an inductive encoder system configured to measure the relative position between two elements along a measuring axis, The inductive encoder system comprises: a scale extending along the measurement axis direction, the scale comprising a periodic scale pattern, the periodic scale pattern comprising a signal modulation element; a detector portion, the detector portion being configured to be positioned adjacent to the periodic scale pattern and to move relative to the periodic scale pattern along the measurement axis direction, the detector portion comprising: a field generating portion PRTFGE configured to generate a varying magnetic flux in response to a drive signal; and a sensing portion PRTSEN comprising one or more sets of sensing elements arranged along the measuring axis direction, wherein each set of sensing elements is coupled to a plurality of sensor through-holes, and the sensing portion PRTSEN is configured to provide a detector signal responsive to a local influence on the varying magnetic flux provided by adjacent signal modulating elements of the periodic scale pattern; and a plurality of shielding structures SST, wherein each shielding structure SST is positioned adjacent to the set of sensor vias and comprises a plurality of shielding vias, and in each shielding structure SST, one or more shielding loops are formed by the plurality of shielding vias coupled together by conductor portions; The method comprises: providing a drive signal causing said field generating portion PRTFGE to generate said varying magnetic flux, wherein said operation of said field generating portion PRTFGE generates one or more stray magnetic fields; receiving a detector signal from the sensing portion PRTSEN, wherein at least one set of sensor vias is at least partially shielded from the one or more stray magnetic fields by the plurality of shielding structures; and A relative position between the detector portion and the scale is determined based at least in part on the detector signal.

18. The method of claim 17, wherein at least some of the at least one sensor via set form at least a portion of one or more parasitic loops, and the shielding of the at least one sensor via set reduces an offset signal portion in the detector signal that would otherwise be caused by the one or more stray magnetic fields coupled to the one or more parasitic loops in the absence of the shielding structure.

19. The method of claim 17, wherein the relative position does not include positional errors that would otherwise result if the shielding structure were not present.

20. A detector portion for use in an inductive encoder configured to measure a relative position between two elements along a measuring axis direction, the encoder comprising a scale extending along the measuring axis direction, the scale comprising a periodic scale pattern, the periodic scale pattern comprising signal modulating elements, wherein the detector portion is configured to be positioned adjacent to the periodic scale pattern and to move relative to the periodic scale pattern along the measuring axis direction, the detector portion comprising: a field generating portion PRTFGE configured to generate a varying magnetic flux in response to a drive signal; a sensing portion PRTSEN comprising one or more sets of sensing elements arranged along the measurement axis direction, wherein each set of sensing elements is coupled to a plurality of sensor through-holes, and the sensing portion PRTSEN is configured to provide a detector signal responsive to a localized influence on the varying magnetic flux provided by adjacent signal modulating elements of the periodic scale pattern; and A plurality of shielding structures SST, wherein each shielding structure SST is positioned adjacent to the set of sensor vias and includes a plurality of shielding vias, and in each shielding structure SST, one or more shielding loops are formed by the plurality of shielding vias coupled together by conductor portions.

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