Proximity detector arrangement

Abstract

To enable especially mobile electronic devices to reduce power consumption and to extend the battery lifetime while still providing a highly precise and reliable proximity detection and / or motion detection.SOLUTION: In one aspect, a wireless proximity detector arrangement (10) comprises: at least one antenna (12); an impedance sensing circuit (14) coupled to the antenna (12) and operable to quantitatively measure variations of an antenna impedance over time; and a controller (30) connected to the impedance sensing circuit (14) and operable to selectively deactivate and / or selectively activate the impedance sensing circuit (14) for a predefined time interval.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] In one aspect, the present invention relates to an array of wireless proximity detectors. In another aspect, the present invention relates to an electronic device comprising a user interface equipped with an array of wireless proximity detectors. In another aspect, the present invention relates to a method for detecting and / or quantitatively measuring the spatio-temporal movement of an object relative to an array of wireless proximity detectors.

Background Art

[0002] Some wireless or non-contact motion detection for user interfaces utilize the radar principle, in which microwaves are generated to detect motion or distance between a receiver and a reflecting object, the object to be detected reflects the microwaves, and finally the receiver receives the microwaves. The document European Patent No. 2 871 590 (B1) also discloses a portable system for user-controlled audio output or display output comprising a wearable physical activity monitoring device with a wireless proximity detection module. In this document, the wireless proximity detection module is configured to perform a measurement of the proximity of an input control entity by measuring a change in antenna impedance or a change in antenna resonance frequency caused by moving an input control entity relative to at least one antenna.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In view of the above, a particular objective is to reduce power consumption and extend battery life while still providing high-precision and high-reliability proximity detection and / or motion detection, particularly with respect to mobile electronic devices.

Means for Solving the Problem

[0005] The above object is solved and appropriately addressed by a wireless proximity detector array according to the features of the independent claims, by an electronic device, and by a method for detecting and / or quantitatively measuring the spatio-temporal movement of an object. Preferred embodiments or solutions are the subject matter of the corresponding dependent claims.

[0006] According to one aspect, a wireless proximity detector array is provided. The wireless proximity detector array comprises at least one antenna. The detector array further comprises an impedance sensing circuit operable to be coupled to the antenna and quantitatively measure variations in the antenna impedance over time. The wireless proximity detector array further comprises a controller connected to the impedance sensing circuit and operable to selectively deactivate and selectively activate the impedance sensing circuit at a predetermined time interval.

[0007] By temporally deactivating the impedance sensing circuit, the power or energy for operating the impedance sensing circuit can be correspondingly saved. In this way, the overall energy or power consumption of the impedance sensing circuit can be reduced, and in the case of a mobile electronic device that may be driven or operated by a battery, the battery life can be extended.

[0008] Typically according to other examples, the controller is operable to periodically deactivate and periodically activate the impedance sensing circuit. In an example, the activation of the impedance sensing circuit can be performed based on a predetermined schedule. In some examples, the controller may be operable to clock control the impedance sensing circuit, such that the impedance sensing circuit is activated at a predetermined point in time or after a predetermined time interval has elapsed.

[0009] The controller may also be operable to keep or maintain the impedance detection circuit in an activation mode or activation state during a predetermined time interval. After this activation time interval has elapsed, the controller may also be operable to deactivate the impedance detection circuit during and / or at certain times during a predetermined non-activation time interval.

[0010] Thus, speaking of the periodic or regular activation and deactivation of the impedance detection circuit, the time interval during which the impedance detection circuit is in an inactive state may be referred to as an inactive state detection time interval. The period during which the impedance detection circuit is in an active state, or is activated by the controller, may be referred to as an active state detection time interval. The sum of the active state detection time intervals and the sum of the inactive state detection time intervals are equal to the entire detection time interval, that is, the time interval divided into intervals during which the impedance detection circuit is in an active state or an inactive state, respectively.

[0011] According to some examples, the active state detection time interval is shorter than the inactive state detection time interval. In this way, the power consumption of the wireless proximity detector array, and in particular of the impedance detection circuit, can be reduced. In some examples, the sampling time for periodically activating the impedance detection circuit may be on the order of a fraction of a microsecond (μs), such as a few tenths of a microsecond. Thus, the sampling period, and thus the sum of the active state detection time interval and the inactive state detection time interval, may be less than about 10 ms, less than 15 ms, less than 20 ms, or less than 50 ms at most. The inactive state detection time interval may be longer than the active state time interval. In some examples, the sampling period may be about 10 ms, and the active state detection time interval may be on the order of 100 μs in length.

[0012] In an example, at a sampling period of about 10 ms, the controller may operate to deactivate the impedance detection circuit for a period of about 9.9 ms and then operate to activate the impedance detection circuit for a subsequent time interval of about 100 μs. Thereafter, the controller may operate to switch the impedance detection circuit to the deactivated mode.

[0013] The wireless proximity detector array, and in particular its controller, can operate to repeatedly and periodically sample, i.e., to periodically activate the impedance detection circuit, so as to quantitatively measure the distance between a moving or non - moving object and at least one antenna of the wireless proximity detector array. When activated, the impedance detection circuit can operate to measure the variation of the antenna impedance over time. The controller may further be operable to derive movement or position data indicative of the relative position or movement of the object with respect to the antenna based on an analysis of the impedance variations measured during a number of activation detection time intervals of the impedance detection circuit. In this way, the controller can derive at least one of the position and movement of the object that affects the antenna impedance when moving close to at least one antenna.

[0014] In some examples, the impedance detection circuit is operable to quantitatively measure the variation of the antenna impedance over time. In this regard, the impedance variation includes not only the variation of the complex electrical resistance of the antenna, but also the variation of the resonant frequency, or the frequency variation of the antenna or the corresponding antenna circuit connected to the antenna.

[0015] According to another example, the controller of the wireless proximity detector is operable to selectively activate the impedance detection circuit in pulse mode. Also, the impedance detection circuit may be activated only during a predetermined time interval and / or at a predetermined point in time, for example, according to a predetermined sampling schedule. In this way, when the impedance detection circuit is operating in pulse mode, energy can be saved as compared to an operating state in which the impedance detection circuit is continuously driven or operated.

[0016] According to another example, the impedance detection circuit includes a measurement oscillator connected to the antenna. By measuring at least one of a control signal for operating the measurement oscillator, an amplitude signal of the measurement oscillator, and a frequency signal of the measurement oscillator, fluctuations in the antenna impedance can be quantitatively measured. In this case, in one example, at least one antenna may be driven, for example, with a radiofrequency (RF) signal in the 2.44 GHz band. The oscillator can operate or drive the antenna in RF transmission mode, and an object in the immediate vicinity, for example, in the near-field of the antenna, may have a measurable effect on the impedance of the antenna.

[0017] Moreover, by measuring the impedance or a function of the antenna impedance, the movement, position, and / or can be detected, characterized, and / or quantitatively measured of an object immediately adjacent to the antenna, that is, in the near-field of the antenna.

[0018] According to another example, a measurement oscillator is connected to an automatic gain controller. The automatic gain controller is operable to restore the signal amplitude of the measurement oscillator connected or coupled to at least one antenna. As an object moves near or reaches near at least one antenna, e.g., moves into the near field of the antenna, a corresponding correction of the antenna impedance progresses. This impedance correction induced by an object moving in the near field of the antenna typically causes a correction or change in the drive voltage or drive current of the corresponding oscillator. By the automatic gain controller, one of the control signals for operating the oscillator, e.g., a bias current or a bias voltage, is automatically adjusted so that the signal amplitude of the measurement oscillator remains constant. In this case, since the antenna impedance varies, the drive signal for the measurement oscillator undergoes a corresponding change, which is measurable and indicates the variation of the antenna impedance.

[0019] According to another example, the automatic gain controller is operable to provide an amplitude control bias current to the measurement oscillator, and the amplitude control bias current undergoes a measurable variation in response to the variation of the antenna impedance. Accordingly, using the automatic gain controller, the bias current or bias voltage of the oscillator connected or coupled to at least one antenna may undergo a measurable variation, and this measurable variation serves to maintain or restore the output signal or signal amplitude of the measurement oscillator. These measurable variations of the drive signal for driving the measurement oscillator directly indicate the impedance correction of the antenna.

[0020] According to another example, the impedance detection circuit comprises an amplitude detector connected to the output of the measurement oscillator. The amplitude detector enables the measurement oscillator to operate in a different mode as compared to the automatic gain controller mode. In this case, according to another example, the measurement oscillator can operate with a constant bias current or a constant bias voltage. The amplitude detector is operable to measure the variation in the signal amplitude of the measurement oscillator in response to the variation in the antenna impedance. In this case, an object in motion, or an object located in the immediate vicinity of at least one antenna, i.e., in the near field of the antenna, may induce a variation in the antenna impedance, and as a result, when driven by the measurement oscillator, in particular when operating the measurement oscillator with a bias current or a bias voltage that is kept constant or restored, a measurable variation in the signal amplitude of the measurement oscillator can be obtained.

[0021] The amplitude detector is typically connected to the output of the measurement oscillator and is operable to detect the variation in the amplitude of the measurement oscillator. The variation in the amplitude of the measurement oscillator may directly indicate the corresponding variation in the antenna impedance.

[0022] According to another example, the impedance detection circuit comprises a phase locked loop (PLL) connected to the oscillator and also connected to a reference frequency generator. The reference frequency generator is operable to provide a reference frequency signal. By means of the phase locked loop, the frequency of the oscillator can be maintained or locked to the reference frequency, for example, the frequency of the reference frequency signal provided by the reference frequency generator. The variation in the antenna impedance typically induces a displacement or variation in the resonant frequency of the antenna, and this displacement or variation may well induce a frequency control signal of the phase locked loop, which can be measured by the controller and thus directly indicates the impedance variation.

[0023] Typically, a phase-locked loop comprises a frequency divider connected to the signal output of an oscillator. The output of the frequency divider is provided to a phase comparator. Also, the output of a reference frequency generator is provided to the phase comparator as well. The phase comparator is operable to compare frequencies, for example, the operating frequency of the oscillator and the reference frequency. The output of the phase comparator is connected to the oscillator via a feedback path through a loop filter. In this case, the loop filter may be operable to generate a corrected drive signal or a compensating drive signal for the oscillator in order to reduce or remove a phase mismatch or a phase offset between the phase of the oscillator signal and the phase of the reference frequency signal. The control signal generated or provided by the loop filter, which is operable to reduce the phase or frequency mismatch between the phase or frequency of the oscillator compared to the reference frequency, may in this case directly indicate a variation in the impedance of at least one antenna, which may be due to an object present immediately next to the antenna or moving in the vicinity of the antenna.

[0024] Accordingly, in another example, the phase-locked loop is operable to restore the frequency of the oscillator by a frequency control signal derivable by comparing the relative phase between the output signal of the oscillator and the reference signal provided by the reference frequency generator. In this way, by measuring or monitoring the frequency control signal present at the output of the measurement oscillator connected to the phase-locked loop, the variation in the impedance of at least one antenna can be directly monitored and / or quantitatively measured.

[0025] According to another example, the impedance detection circuit includes a frequency counter connected to the output of the oscillator. In this case, the measurement oscillator may not be part of the phase-locked loop. The measurement oscillator may simply operate based on a fairly constant unmodified frequency control signal. Any variation in the antenna impedance may have a measurable effect on the frequency and / or phase of the measurement oscillator. The frequency counter is operable to directly measure any modification or change in the phase and / or frequency of the measurement oscillator, in particular. In this case, for example, the controller of the wireless proximity detector array is configured to reset the frequency counter at a predetermined time interval and define start and stop times to start and end frequency counting respectively.

[0026] The frequency counter may be operable to measure the frequency and / or phase of the input signal obtained from the measurement oscillator, and this phase or frequency directly indicates any fluctuation or modification of the phase or frequency compared to the reference frequency or reference phase. In this way, the frequency counter may be operable to directly and quantitatively measure any variation in the frequency or transfer of the measurement oscillator due to impedance variations of the impedance of at least one antenna.

[0027] According to another example, the oscillator is operable to change the oscillation frequency in response to impedance variations of the antenna. The frequency counter of the impedance detection circuit is further operable to quantitatively measure one or more oscillation frequency variations. In this way, the frequency counter is directly operable to provide variations in the oscillation frequency due to impedance variations of at least one antenna. The degree of oscillation frequency variation may be directly correlated with the magnitude or degree of the antenna impedance variation. In this way, the antenna impedance variation can be measured not only qualitatively but also quantitatively. This provides a fairly accurate measurement of the position, proximity, or movement of an object in the immediate vicinity of at least one antenna.

[0028] According to another example, the impedance detection circuit is operable to drive the oscillator in a spectrum spreading mode. In the spectrum spreading mode, an operating signal or a driving signal of the oscillator is generated or provided with a specific bandwidth and is spread in a planned manner in the frequency domain, resulting in a signal having a wider bandwidth. By operating the oscillator in the spectrum spreading mode, it is possible to avoid the amplitude and frequency of the oscillator being corrected through the frequency pulling effect due to in-band interference. Also, since the measurement oscillator is directly connected to at least one antenna, spread modulation is one way to avoid the antenna radiating out-of-specification power.

[0029] According to another example, the controller has a neural network and a digital storage device or digital memory connected or coupled to the neural network. Moreover, the controller is connected to the output of the impedance detection circuit to derive or determine the distance or movement characteristics of at least one object located right next to at least one antenna, and this movement or position of the object induces impedance variations.

[0030] The digital storage device of the controller is operable to store a large number of temporal evolutions of the impedance signal. The neural network is configured to map at least one temporal evolution of the impedance signal to a spatio-temporal characteristic movement pattern of the object with respect to the antenna. The neural network may be operable to provide the best match during the temporal evolution of the impedance signal measured by the impedance detection circuit using the already mapped measurement signal, or the evolution of the measurement signal, assigned to the corresponding spatio-temporal characteristic movement pattern of the object with respect to at least one antenna. In this way, since the neural network may provide not only a certain amount of training but also a constant and invariant memory or a repeated memory regarding the spatio-temporal movement pattern of the object in the digital storage device, it may effectively compensate for external factors such as the thermal drift of the impedance detection circuit.

[0031] Furthermore, the neural network may, in combination with a digital storage device, enable and provide complete behavior recognition, i.e., a clearly defined spatio-temporal movement pattern of an object moving in a clearly defined manner or method with respect to at least one antenna.

[0032] Generally, the wireless proximity detector array can be operated and driven with relatively low energy consumption, and the oscillation power only needs to be sufficient to operate at least one of the above-described hardware components, i.e., the measurement oscillator, frequency divider, phase comparator, filter, or counter. The antenna does not actually need to radiate or broadcast electromagnetic energy.

[0033] According to another aspect, there is further provided an electronic device comprising a user interface for controlling or modifying the functions of the electronic device. The user interface comprises a wireless proximity detector array as described above. To that extent, all the effects, features, and benefits described above in relation to the wireless proximity detector apply equally to the electronic device, and vice versa.

[0034] Typically, the electronic device is a mobile electronic device. The electronic device may be operated or driven by a mobile energy source such as a battery or a rechargeable battery. By utilizing the wireless proximity detector array as described above, the overall power consumption of the electronic device can be reduced. Thus, the battery life may be extended in a beneficial manner.

[0035] In yet another aspect, the present invention also relates to a method for detecting and / or quantitatively measuring the spatio-temporal movement of an object relative to an array of wireless proximity detectors, as described above. The method comprises: a) providing an array of wireless proximity detectors as described above; b) activating the impedance sensing circuit of the array of wireless proximity detectors for a predetermined time interval; c) quantitatively measuring the variation of the antenna impedance over time by an impedance sensing circuit connected to the antenna of the array of wireless proximity detectors; and d) deactivating the impedance sensing circuit for a predetermined time interval. Optionally, according to step e), steps b), c), and d) are repeated, for example even multiple times. Then, simultaneously with the execution of one of steps b), c), d), or e), in step f), based on the variation of the antenna impedance, the spatio-temporal movement or position of the object relative to the array of wireless proximity detectors is derived or quantitatively determined.

[0036] Typically, a method for detecting and / or quantitatively measuring the spatio-temporal movement of an object, as described herein, requires an array of wireless proximity detectors to perform as described above. To that extent, all features, effects, and benefits described above in connection with the array of wireless proximity detectors equally apply to a method for detecting and / or quantitatively measuring the spatio-temporal movement of an object relative to an array of wireless proximity detectors, for example relative to at least one antenna of the array of wireless proximity detectors.

[0037] Hereinafter, numerous examples of the present invention will be described in more detail with reference to the drawings.

Brief Description of the Drawings

[0038]

Figure 1

Figure 2

Figure 3

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Figure 9

Figure 10

Figure 11

DETAILED DESCRIPTION OF THE INVENTION

[0039] FIG. 9 shows an example of a wireless proximity detector array 10. The detector array 10 includes at least one antenna 12 connected to an impedance sensing circuit 14 by a connection device 13. The connection device 13 may include or provide an impedance matching circuit so that the impedance sensing circuit 14 can measure the impedance of the antenna 12. The output of the impedance sensing circuit 14 is connected to a controller 30. The controller 30 is operable to process the output signal provided by the impedance sensing circuit 14. The controller 30 may also be operable to control or at least partially control the impedance sensing circuit 14. For this purpose, the controller 30 is connected to a control input 15 of the impedance sensing circuit 14.

[0040] Typically, the controller 30 includes at least one digital processor to process the signal obtained from the impedance detection circuit 14 in a digital manner. By processing a signal that can be obtained from the impedance detection circuit 14, the controller 30 may be operable to determine the relative position, distance, or movement pattern of the object 11 located immediately adjacent to the antenna 12. The movement or presence of the object 11 located immediately adjacent to the antenna 12 causes a change in the impedance of the antenna 12, and this impedance change can be measured by the impedance detection circuit 14. The controller 30 is operable to provide a signal and a signal output 31 mode, and this signal indicates the relative position, distance, and / or movement pattern of the object 11 with respect to the antenna 12.

[0041] In some examples, the controller 30 includes not only the digital storage device 35 but also the neural network 32. The neural network 32 may be operable to map at least one or a sequence of impedance signals that can be obtained from the impedance detection circuit 14 to a predetermined or already measured spatio-temporal movement pattern of the object 11, such as that stored or provided in the digital storage device 35.

[0042] In practice, the controller 30 may include an output that provides an electrical or digital signal indicating the position or movement of the object 11 with respect to at least one antenna 12.

[0043] Typically, as shown in FIG. 11, the proximity detector array 10 is part of the user interface 50 of the electronic device 80. The electronic device 80 may be implemented as a portable electronic device. The electronic device 80 may be battery-powered. As such, the electronic device 80 may include a battery 60 that provides electrical energy not only for the user interface 50 but also for other electronically implemented functional components of the electronic device 80. In some examples, the electronic device 80 is implemented as one of a mobile phone, a smartphone, a tablet computer, a laptop computer, or a watch or other portable information terminal.

[0044] FIG. 1 provides a configuration diagram of at least one antenna 12, a coupling device 13, and an impedance detection circuit 14. The impedance detection circuit 14 includes a first output fa and a second output fb. In this case, the first output fa is configured to provide a signal indicating the real part of the antenna impedance. The other output fb is configured to provide a signal indicating the imaginary part of the antenna impedance of the antenna 12.

[0045] The object 11 movable relative to the antenna may be a body part of the user, such as one or several fingers of the user, or the user's hand. In some examples, the object 11 may move relative to at least one antenna according to a predetermined behavior or other predetermined spatio-temporal movement pattern that the impedance detection circuit 14 may detect.

[0046] To conserve the energy of the impedance detection circuit 14 and thus the entire wireless proximity detector array 10 and reduce power consumption, the control input 15 of the impedance detection circuit 14 is provided to be operable to at least temporally deactivate and / or at least temporally activate the operation of the impedance detection circuit 14. The control input 15 is controllable by the controller 30. The control input 15 may operate in a pulse mode. As shown in FIG. 2, a control signal SC may be provided to the control input 15, and this control signal SC is generated by the controller 30. At time t0, the control signal SC is at logic 0. At time t1, the control signal SC switches to logic 1. In this case, the control signal SC defines the activation state of the impedance detection circuit 14. The control signal SC is in an active state during the period from t1 to t2. At time t2, the control signal SC switches back to logic 0 that deactivates the operation of the impedance detection circuit again.

[0047] At a further time point t3, the impedance detection circuit switches back on by raising the control signal SC from logic 0 to logic 1 until the time interval t4 - t3 has elapsed.

[0048] The time intervals from t1 to t3 may represent a detection time interval or a sampling rate or a sampling period. The time interval from t2 to t1 may define an active state detection time interval, and the time interval from t2 to t3 may define an inactive state detection time interval. As shown in FIG. 2, the inactive state time interval is much longer than the active state time interval. During the inactive state detection time interval, the power consumption of the impedance detection circuit is minimized.

[0049] The pulsed operation of the impedance detection circuit 14 during the active state detection time interval, i.e., during the time interval from t2 to t1 or from t4 to t3, serves to reduce the overall power consumption of the impedance detection circuit. In this way, not only the power consumption of the wireless proximity detector array but also the battery life of the battery 60 of the corresponding electronic device 80 can be extended or prolonged.

[0050] FIG. 8 schematically illustrates the spatial evolution of the complex reflection S11 that reflects the complex impedance of the antenna 12 in this way. In this case, along the y direction, the real part of S11 is provided. Along the x direction, the imaginary part of the reflection coefficient S11 is reflected. Vertically, the spatial evolution distance between the antenna 12 and the object 11 is shown in centimeters (cm). Such a spatial evolution of the antenna impedance may indicate characteristic positions or movement patterns of the object 11 when moving right next to at least one antenna 12, i.e., in the near-field.

[0051] As described below, the real and imaginary parts of the antenna impedance may be measured by the impedance detection circuit 14. In this case, to measure the antenna impedance, the impedance detection circuit 14 comprises a measurement oscillator 20. The measurement oscillator 20 may be implemented as a modulation oscillator operating at or near a resonance frequency of about 2.44 GHz and / or as a voltage-controlled oscillator. In the example of FIG. 3, the impedance detection circuit 14 includes an automatic gain controller 22 arranged in a feedback loop configuration with the measurement oscillator 20. Thus, the output of the automatic gain controller 22 serves to provide a drive signal for operating or driving the oscillator 20 using at least one of a bias current and a bias voltage.

[0052] The output signal of the oscillator 20 directly connected to the antenna 12 is provided to the automatic gain controller 22 as an input to the coupling device 13. Typically, the automatic gain controller 22 operates to provide a constant bias current or a constant bias voltage at the input of the measurement oscillator 20. Each control signal, for example in the form of a bias current or a bias voltage, is measurable at the fa of the automatic gain controller 22 and directly indicates the measurable variation of the antenna impedance. This operating mode of the automatic gain controller is immediately apparent from FIG. 4.

[0053] Instead of the automatic gain controller 22, an amplitude detector 24 as shown in FIG. 5 may be provided. In this case, the amplitude detector 24 is connected to the output of the measurement oscillator 20. The measurement oscillator 20 operates or is driven by a fairly constant drive signal, for example, by a constant drive current or bias current. In this case, any modification or fluctuation of the antenna impedance may cause a corresponding measurable change in the amplitude of the oscillation signal provided at the output 21 of the oscillator 20. As shown in FIG. 5, the output 21 of the measurement oscillator 20 is connected to an amplitude detector 24 that is directly operable to quantitatively measure any variation in the amplitude of the output signal of the measurement oscillator 20, which variation is typically induced by the movement of the object or by a modification of the antenna impedance. Accordingly, the output fa’ of the amplitude detector directly indicates the real part of the reflection coefficient S11 of the antenna impedance.

[0054] The block diagrams according to FIGS. 6 and 7 show two other approaches for measuring the complex part of the reflection coefficient S11 representing the antenna impedance. In the example of FIG. 6, the impedance sensing circuit 14 comprises a phase-locked loop 26. In this case, the output 21 of the measurement oscillator 20 is connected to a frequency divider 25 implemented, for example, as an RF frequency divider. The output of the frequency divider 25 is connected to a phase comparator 27, which is further connected to a reference frequency generator 28. The reference frequency generator 28 is operable to provide a clearly defined reference frequency signal to the phase comparator 27.

[0055] The phase comparator 27 is operable to determine and / or measure the phase difference between the oscillation of the measurement oscillator 20 and the oscillation of the reference frequency generator 28. The corresponding comparison signal generated by the phase comparator 27 is provided to a loop filter 23, which generates a corresponding frequency control signal, for example, a frequency control voltage, for driving or biasing the measurement oscillator 20. Accordingly, the loop filter 23 provides a control signal or bias signal fb that directly indicates the imaginary part of the reflection coefficient S11 of the antenna impedance.

[0056] Instead of the solution shown in FIG. 6, a frequency counter 29 connected to the output 21 of the measurement oscillator 20 may be further provided, and the frequency counter 29 may be operable to directly measure fluctuations in the frequency of the measurement oscillator 20, which fluctuations may be due to changes in the impedance of the antenna 12 coupled or connected to the measurement oscillator 20. In this case, the frequency counter 29 comprises a reset input 33 and a count enable input 34. The input lines 33, 34 may be operated or driven by the controller 30. By setting the reset input 33 to logic 1, the counter 29 is reset. By enabling the count enable input 34, for example by setting the input 34 to logic 1, the frequency counter 29 starts counting. Typically, the count enable input 34 is active for a well-defined and fairly accurate time interval and sometimes during that time interval, such that any fluctuations in the frequency of the measurement oscillator 20 can be directly measured. From the measurable fluctuations in the oscillation frequency and / or phase of the measurement oscillator 20, the imaginary part of the reflection coefficient S11 of the antenna impedance may be directly derived.

[0057] Both signals, i.e., the real part fa and the imaginary part fb of the measurable reflection coefficient, are provided as inputs to the controller 30, and the controller 30 is operable to map each signal to a predetermined spatio-temporal movement pattern of the object 11 with respect to at least one antenna 12.

[0058] As further shown in FIG. 10, a method is provided for detecting and / or quantitatively measuring the spatio-temporal movement of an object 11, such as a user's hand or finger, relative to the wireless proximity detector array 10. In this case, in a first step 100, a wireless proximity detector array 10 is provided. In step 102, the impedance sensing circuit 14 of the wireless or non-contact proximity detector array 10 is activated for a predetermined time interval. Then, while it is activated, in step 104, a quantitative measurement of the variation in the antenna impedance is made over time by the impedance sensing circuit 14.

[0059] Thereafter, in step 106, the impedance detection circuit is deactivated for a predetermined time interval. Next, the method may continue with step 108 where the impedance detection circuit 14 remains in the inactive state. In this case, the controller 30 may simply perform a counting operation until the predetermined time interval has elapsed. Thereafter, the procedure returns to step 102 where the impedance detection circuit 14 is reactivated. The impedance measurement performed during step 104 may be directly evaluated or further processed by the controller 30 to assign or map the measurement signal to a predetermined spatio-temporal movement pattern of the object 11 with respect to the antenna 12. Periodically deactivating the impedance detection circuit 14 helps to conserve energy and extend battery life.

Explanation of Signs

[0060] 10 Proximity detector array 11 Object 12 Antenna 13 Connecting device 14 Impedance detection circuit 15 Control input 20 Oscillator 21 Oscillator output 22 Automatic gain controller 23 Loop filter 24 Amplitude detector 25 Frequency divider 26 Phase-locked loop 27 Phase comparator 28 Reference frequency generator 29 Frequency counter 30 Controller 31 Output 32 Neural network 33 Reset input 34 Count enable input 35 Digital storage device 50 User interface 60 Battery 80 Electronic device fa Real part of antenna impedance Output of the fa amplitude detector Imaginary part of the fb antenna impedance SC control signal Complex reflection coefficient S11 Times t0, t1, t2, t3, t4 x and y directions

Claims

1. A wireless proximity detector array (10), comprising: at least one antenna (12), an impedance sensing circuit (14) coupled to said antenna (12) and operable to quantitatively measure variations in antenna impedance over time; a controller (30) connected to said impedance sensing circuit (14) and operable to at least one of selectively deactivate and selectively activate said impedance sensing circuit (14) during a predetermined time interval; A wireless proximity detector array (10) comprising:

2. The wireless proximity detector array (10) of claim 1, wherein the controller (30) is operable to selectively activate the impedance sensing circuit (14) in a pulsed mode.

3. 2. The wireless proximity detector array of claim 1, wherein the impedance sensing circuit comprises a measurement oscillator coupled to the antenna, and the variation in the antenna impedance is quantitatively measurable by measuring at least one of a control signal for operating the measurement oscillator, an amplitude signal of the measurement oscillator, and a frequency signal of the measurement oscillator.

4. 4. The wireless proximity detector array (10) of claim 3, wherein the measurement oscillator (20) is coupled to an automatic gain controller (22) operable to restore a signal amplitude of the measurement oscillator (20).

5. 5. The wireless proximity detector array of claim 4, wherein the automatic gain controller is operable to provide an amplitude-controlled bias current to the measurement oscillator, the amplitude-controlled bias current undergoing a measurable variation in response to the variation in the antenna impedance.

6. 4. The wireless proximity detector array (10) of claim 3, wherein the impedance sensing circuit (14) comprises an amplitude detector (24) connected to an output of the measurement oscillator (20).

7. 7. The wireless proximity detector array of claim 6, wherein the measurement oscillator is operable with a constant bias current and the amplitude detector is operable to measure variations in signal amplitude of the measurement oscillator in response to the variations in the antenna impedance.

8. 4. The wireless proximity detector array (10) of claim 3, wherein the impedance sensing circuit (14) comprises a phase locked loop (26) coupled to the measurement oscillator (20) and to a reference frequency generator (28).

9. 9. The wireless proximity detector array (10) of claim 8, wherein the phase locked loop (26) is operable to restore the frequency of the measurement oscillator (20) by a frequency control signal derivable by comparing the relative phase between the output signal of the measurement oscillator (20) and a reference signal provided by the reference frequency generator (28).

10. 4. The wireless proximity detector array (10) of claim 3, wherein the impedance sensing circuit (14) comprises a frequency counter (29) connected to an output of the measurement oscillator (20).

11. 11. The wireless proximity detector array (10) of claim 10, wherein the measurement oscillator (20) is operable to vary an oscillation frequency in response to impedance variations of the antenna (12), and the frequency counter (29) is operable to quantitatively measure oscillation frequency variations.

12. The wireless proximity detector array (10) of claim 3, wherein the impedance sensing circuit (14) is operable to drive the measurement oscillator (20) in a spread spectrum mode.

13. 2. The wireless proximity detector array (10) of claim 1, wherein the controller (30) comprises a neural network (32) and a digital storage device (35), the digital storage device (35) operable to store numerous time evolutions of impedance signals, and the neural network (32) configured to map the time evolution of at least one of the impedance signals to a characteristic spatiotemporal movement pattern of an object (11) relative to the antenna (12).

14. 1. An electronic device (80) comprising a user interface (50) for controlling or modifying functionality of the electronic device (80), the user interface (50) comprising a wireless proximity detector array (10) according to claim 1.

15. A method for detecting and / or quantitatively measuring the spatiotemporal movement of an object (11) relative to a wireless proximity detector array (10), comprising: a) providing a wireless proximity detector array (10) according to claim 1; b) activating an impedance sensing circuit (14) of said wireless proximity detector array (10) for a predetermined time interval; c) quantitatively measuring the variation in antenna impedance over time with the impedance sensing circuitry (14) coupled to the antenna (12) of the wireless proximity detector array (10); d) deactivating said impedance sensing circuit (14) for a predetermined time interval; e) optionally repeating steps b), c), and d); f) deriving or quantitatively determining the spatiotemporal motion of the object (11) relative to the wireless proximity detector array (10) based on the variations in the antenna impedance. A method for providing the above.

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