Proximity detector array

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 invention relates to a wireless proximity detector array. In another aspect, the invention relates to an electronic device with a user interface equipped with a wireless proximity detector array. In another aspect, the invention relates to a method for detecting and / or quantitatively measuring the spatiotemporal movement of an object relative to a wireless proximity detector array. [Background technology]

[0002] Some wireless or contactless motion detection for user interfaces utilizes the radar principle, in which microwaves are generated, reflected by the object to be detected, and finally received by the receiver to detect movement or distance between a receiver and a reflecting object. The document EP 2 871 590 B1 also discloses a portable system for user-controlled audio 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 resonant frequency caused by moving the input control entity relative to at least one antenna. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] European Patent No. 2 871 590(B1) Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above, it is a particular objective, particularly with respect to mobile electronic devices, to reduce power consumption and extend battery life while still providing accurate and reliable proximity and / or motion detection. [Means for solving the problem]

[0005] The above-mentioned objects are solved or adequately addressed by a wireless proximity detector array, by an electronic device and by a method for detecting and / or quantitatively measuring the movement of an object in space and time according to the features of the independent claims. Preferred embodiments or solutions are the subject of the corresponding dependent claims.

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

[0007] By temporarily deactivating the impedance sensing circuit, a corresponding power or energy saving can be achieved for operating the impedance sensing circuit, thus reducing the overall energy or power consumption of the impedance sensing circuit and, in the case of mobile electronic devices that may be battery powered or operated, extending battery life.

[0008] Typically, according to another example, the controller is operable to periodically deactivate and periodically activate the impedance sensing circuit. Illustratively, activation of the impedance sensing circuit may occur based on a predetermined schedule. In some examples, the controller may be operable to clock the impedance sensing circuit so that it is activated at a predetermined time or after a predetermined time interval has elapsed.

[0009] The controller may also be operable to hold or maintain the impedance sensing circuit in an activation mode or state for a predetermined time interval, after which the controller may also be operable to deactivate the impedance sensing circuit for a predetermined inactivity time interval and / or some time during the predetermined inactivity time interval.

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

[0011] According to some examples, the activity detection time interval is shorter than the inactivity detection time interval. In this way, power consumption of the wireless proximity detector array, and particularly of the impedance detection circuit, can be reduced. In some examples, the sampling time for periodically activating the impedance detection circuit can be as short as a few tenths of a microsecond (μs). Thus, the sampling period, and thus the sum of the activity detection time interval and the inactivity detection time interval, is at most approximately less than 10 ms, 15 ms, 20 ms, or 50 ms. The inactivity detection time interval can be longer than the activity time interval. In some examples, the sampling period can be approximately 10 ms, and the activity detection time interval can be as short as 100 μs.

[0012] In an illustrative example, for a sampling period of about 10 ms, the controller may operate to deactivate the impedance sensing circuit for a period of about 9.9 ms, followed by an interval of about 100 μs to activate the impedance sensing circuit, after which the controller may operate to switch the impedance sensing circuit to the deactivated mode.

[0013] The wireless proximity detector array, and in particular its controller, is operable to repeatedly and periodically sample, i.e., periodically activate an impedance sensing circuit, 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 sensing circuit is operable to measure variations in antenna impedance over time. The controller may be further operable to derive motion 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 sensing circuit. In this manner, the controller can derive at least one of the position and movement of the object, which, when moving in close proximity to the at least one antenna, affects the antenna impedance.

[0014] In some examples, the impedance sensing circuitry is operable to quantitatively measure variations in antenna impedance over time, where impedance variations in this context include not only variations in the complex electrical resistance of the antenna, but also variations in the resonant frequency or frequency of the antenna or a corresponding antenna circuit coupled to the antenna.

[0015] According to another example, the controller of the wireless proximity detector is operable to selectively activate the impedance sensing circuit in a pulsed mode, and the impedance sensing circuit need only be activated for predetermined time intervals and / or at predetermined times, for example according to a predetermined sampling schedule. In this manner, energy can be saved when operating the impedance sensing circuit in a pulsed mode compared to operating conditions in which the impedance sensing circuit is continuously powered or operated.

[0016] According to another example, the impedance sensing circuit includes a measurement oscillator coupled to an antenna. Measurement of 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 can quantitatively measure variations in the antenna impedance. In this case, in one example, the at least one antenna can be driven with a radio frequency (RF) signal, for example, in the 2.44 GHz band. The oscillator can operate or drive the antenna in an RF transmission mode, and nearby objects, e.g., in the near field of the antenna, can have a measurable effect on the antenna's impedance.

[0017] Furthermore, by measuring the impedance, or a function of the antenna impedance, the movement or position of objects in the immediate vicinity of the antenna, i.e., in the near field of the antenna, can be detected, characterized, and / or quantitatively measured.

[0018] According to another example, the measurement oscillator is coupled 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. In response to an object moving near or approaching the at least one antenna, e.g., moving into the near field of the antenna, a corresponding modification of the antenna impedance is developed. This impedance modification, such as that induced by an object moving in the near field of the antenna, typically causes a corresponding modification or change of the oscillator's drive voltage or drive current. The automatic gain controller automatically adjusts one of the control signals for operating the oscillator, e.g., the bias current or bias voltage, so that the measurement oscillator's signal amplitude remains constant. In this case, as the antenna impedance varies, the drive signal for the measurement oscillator undergoes a corresponding change, which is measurable and indicative of the antenna impedance variation.

[0019] According to another example, the automatic gain controller is operable to provide an amplitude-controlled bias current to the measurement oscillator, the amplitude-controlled bias current undergoing measurable variations in response to variations in antenna impedance. In response, using the automatic gain controller, a bias current or bias voltage of an oscillator coupled or connected to at least one antenna can undergo measurable variations, which act to maintain or restore an output signal or signal amplitude of the measurement oscillator. These measurable variations in the drive signal for driving the measurement oscillator directly indicate antenna impedance modifications.

[0020] According to another example, the impedance sensing circuit includes an amplitude detector connected to the output of the measurement oscillator. The amplitude detector allows the measurement oscillator to operate in a different mode compared to the automatic gain controller mode. In this case, according to another example, the measurement oscillator can be operated with a constant bias current or a constant bias voltage. The amplitude detector is operable to measure variations in the measurement oscillator's signal amplitude in response to variations in the antenna impedance. In this case, a moving object or an object located in the immediate vicinity of at least one antenna, i.e., in the near field of the antenna, can induce variations in the antenna impedance, resulting in measurable variations in the measurement oscillator's signal amplitude when driven by the measurement oscillator, in particular when operating the measurement oscillator with a bias current or bias voltage that is kept constant or restored.

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

[0022] According to another example, the impedance sensing circuit comprises a phase locked loop (PLL) coupled to the oscillator and coupled to a reference frequency generator. The reference frequency generator is operable to provide a reference frequency signal. The phase locked loop enables the frequency of the oscillator to be kept or locked to a reference frequency, e.g., the frequency of the reference frequency signal as provided by the reference frequency generator. Variations in the antenna impedance typically induce a shift or variation in the resonant frequency of the antenna, which may induce a frequency control signal of the phase locked loop, which can be measured by the controller and thus directly indicate 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. The output of a reference frequency generator is also provided to the phase comparator. The phase comparator is operable to compare frequencies, e.g., the operating frequency of the oscillator with 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 or compensating drive signal for the oscillator to reduce or eliminate a phase mismatch or 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, operable to reduce a phase or frequency mismatch between the phase or frequency of the oscillator compared to the reference frequency, in this case directly indicates impedance variations of at least one antenna, which may be due to objects present in the immediate vicinity of the antenna or moving nearby.

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

[0025] According to another example, the impedance sensing circuit comprises a frequency counter connected to the output of the oscillator. In this case, the measurement oscillator may not be part of a phase-locked loop. The measurement oscillator may simply operate on a fairly constant, unmodified frequency control signal. Any variations in the antenna impedance may have a measurable effect on the frequency and / or phase of the measurement oscillator. The frequency counter is particularly operable to directly measure any modifications or changes in the phase and / or frequency of the measurement oscillator. In this case, it is intended to configure the controller of the wireless proximity detector array to, for example, reset the frequency counter at predetermined time intervals to define start and stop times for respectively starting and ending frequency counting.

[0026] The frequency counter may be operable to measure the frequency and / or phase of an input signal obtained from the measurement oscillator, the phase or frequency being directly indicative of any fluctuations or modifications in phase or frequency compared to a reference frequency or phase. In this way, the frequency counter may be operable to directly and quantitatively measure any variations in the frequency or phase of the measurement oscillator due to impedance variations in the impedance of the at least one antenna.

[0027] According to another example, the oscillator is operable to change its oscillation frequency in response to impedance variations of the antenna. The frequency counter of the impedance sensing circuit is further operable to quantitatively measure one or more oscillation frequency variations. In this manner, the frequency counter is operable to directly provide the oscillation frequency variation resulting from the impedance variations of the at least one antenna. The degree of the oscillation frequency variation may be directly correlated to the magnitude or degree of the impedance variations of the antenna. In this manner, the antenna impedance variations 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 vicinity of the at least one antenna.

[0028] According to another example, the impedance sensing circuit can be operable to drive the oscillator in a spread spectrum mode. In spread spectrum mode, the oscillator's operating or driving signal is generated or provided in a specific bandwidth and deliberately spread in the frequency domain, resulting in a signal with a wider bandwidth. Operating the oscillator in spread spectrum mode can prevent in-band interference from modifying the oscillator's amplitude and frequency through the frequency pulling effect. Also, because the measurement oscillator is directly coupled to at least one antenna, spread modulation is one way to prevent the antenna from radiating substandard power.

[0029] According to another example, the controller has a neural network and a digital storage device or digital memory coupled or connected to the neural network. Additionally, the controller is connected to the output of the impedance sensing circuit to derive or determine a distance or movement characteristic of at least one object in the vicinity of the at least one antenna, this movement or position of the object inducing an impedance variation.

[0030] The digital storage device of the controller is operable to store numerous time evolutions of the impedance signals. The neural network is configured to map at least one time evolution of the impedance signals to a characteristic spatiotemporal movement pattern of the object relative to the antenna. The neural network may be operable to provide a best match between the time evolution of the impedance signals as measured by the impedance sensing circuit using an already mapped measurement signal or measurement signal evolution assigned to a corresponding characteristic spatiotemporal movement pattern of the object relative to the at least one antenna. In this way, the neural network may provide not only constant training but also a constant or repeated memory of the object's spatiotemporal movement pattern in the digital storage device, which may effectively compensate for external factors such as thermal drift of the impedance sensing circuit.

[0031] Furthermore, neural networks, in combination with digital storage, may enable and provide complete behavioral recognition, i.e., well-defined spatiotemporal movement patterns of an object moving in a well-defined manner or manner relative to at least one antenna.

[0032] In general, wireless proximity detector arrays can be operated and driven with relatively low energy consumption; the oscillator power only needs to be sufficient to operate at least one of the hardware components mentioned above: the measurement oscillator, frequency divider, phase comparator, filter, or counter. The antenna does not need to actually radiate or broadcast electromagnetic energy.

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

[0034] Typically, the electronic device is a mobile electronic device. The electronic device may be operated or powered by a mobile energy source such as a battery, or a rechargeable battery. By utilizing a wireless proximity detector array as described above, the overall power consumption of the electronic device can be reduced. In this way, 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 spatiotemporal movement of an object relative to a wireless proximity detector array, as described above, comprising the steps of: a) providing a wireless proximity detector array as described above; b) activating an impedance sensing circuit of the wireless proximity detector array for a predetermined time interval; c) quantitatively measuring variations in antenna impedance over time by an impedance sensing circuit coupled to an antenna of the wireless proximity detector array; and d) deactivating the impedance sensing circuit for the predetermined time interval. Optionally, according to step e), steps b), c), and d) are repeated, for example even multiple times. Thereafter, simultaneously with the execution of one of steps b), c), d), or e), step f) derives or quantitatively determines spatiotemporal movement or position of the object relative to the wireless proximity detector array based on the variations in antenna impedance.

[0036] Typically, the methods for detecting and / or quantitatively measuring the spatiotemporal movement of an object as described herein require a wireless proximity detector array as described above, and insofar as all of the features, effects, and benefits described above in relation to the wireless proximity detector array equally apply to the methods for detecting and / or quantitatively measuring the spatiotemporal movement of an object relative to the wireless proximity detector array, e.g., relative to at least one antenna of the wireless proximity detector array.

[0037] In the following, a number of examples of the invention will be described in more detail by reference to the drawings. [Brief explanation of the drawings]

[0038] [Figure 1] 1 illustrates a block diagram of a wireless proximity detector array. [Figure 2] 10 shows a diagram illustrating the repeated activation and deactivation of an impedance sensing circuit over time. [Figure 3] FIG. 1 shows a block diagram of an example wireless proximity detector array. [Figure 4] 1 shows a block diagram of a solution in which the measurement oscillator is operated by an automatic gain controller. [Figure 5] FIG. 10 shows another block diagram illustrating another implementation for operating the measurement oscillator. [Figure 6] FIG. 1 is a block diagram illustrating a phase locked loop connected or coupled to a measurement oscillator. [Figure 7] 10 shows another block diagram of a measurement oscillator connected or coupled to a frequency counter. [Figure 8] 2 illustrates schematically the spatial evolution of the complex impedance of an object moving in the vicinity of at least one antenna; [Figure 9] FIG. 10 is another diagram of a wireless proximity detector array. [Figure 10] 1 is a flow diagram of a method for detecting and / or quantitatively measuring the spatiotemporal motion of an object using a wireless proximity detector array. [Figure 11] FIG. 1 is a block diagram of an electronic device having a user interface equipped with a wireless proximity detector array as described herein. DETAILED DESCRIPTION OF THE INVENTION

[0039] 9 shows an example of a wireless proximity detector array 10. The detector array 10 comprises at least one antenna 12 connected to an impedance sensing circuit 14 by a coupling device 13. The coupling device 13 may comprise or provide an impedance matching circuit to enable the impedance sensing circuit 14 to 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 as 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. To this end, the controller 30 is connected to a control input 15 of the impedance sensing circuit 14.

[0040] Typically, the controller 30 comprises at least one digital processor for digitally processing signals obtained from the impedance sensing circuit 14. By signal processing signals such as those obtainable from the impedance sensing circuit 14, the controller 30 may be operable to determine the relative position, distance, or movement pattern of an object 11 in the vicinity of the antenna 12, the movement or presence of the object 11 in the vicinity of the antenna 12 causing a variation in the impedance of the antenna 12 which is measurable by the impedance sensing circuit 14. The controller 30 is operable to provide a signal and signal output 31 mode, which signal is indicative of 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 a digital storage device 35 but also a neural network 32. The neural network 32 may be operable to map at least one or a sequence of impedance signals, such as may be obtained from the impedance sensing circuit 14, to a predetermined or previously measured spatiotemporal movement pattern of the object 11, as stored or provided in the digital storage device 35.

[0042] In practice, the controller 30 comprises an output that may provide an electrical or digital signal indicative of the position or movement of the object 11 relative to the at least one antenna 12 .

[0043] Typically, as shown in FIG. 11 , the proximity detector array 10 is part of a user interface 50 of an electronic device 80. The electronic device 80 may be implemented as a portable electronic device. The electronic device 80 may be battery-powered. To that extent, 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 personal digital assistant.

[0044] 1 provides a block diagram of at least one antenna 12, a coupling device 13, and an impedance sensing circuit 14. The impedance sensing circuit 14 comprises a first output fa and a second output fb, where the first output fa is configured to provide a signal indicative of the real part of the antenna impedance, and the other output fb is configured to provide a signal indicative of the imaginary part of the antenna impedance of the antenna 12.

[0045] The object 11 that is movable relative to the antennas may be a body part of the user, such as one or more fingers of the user, or the user's hand, etc. In some examples, the object 11 may move relative to the at least one antenna according to a predetermined behavior or other predetermined movement pattern in space and time that the impedance sensing circuit 14 may be able to detect.

[0046] To conserve energy and reduce power consumption of the impedance sensing circuit 14, and thus the entire wireless proximity detector array 10, a control input 15 of the impedance sensing circuit 14 is provided that is operable to at least temporarily deactivate and / or at least temporarily activate operation of the impedance sensing circuit 14. The control input 15 is controllable by the controller 30. The control input 15 may operate in a pulsed 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 sensing circuit 14. The control signal SC is in an active state for a period from t1 to t2. At time t2, the control signal SC switches again to logic 0, again deactivating operation of the impedance sensing circuit.

[0047] At a further time t3, the impedance sensing circuit is switched on again by raising the control signal SC from logic 0 to logic 1 until the time interval t4 to t3 has elapsed.

[0048] The time interval t1-t3 may represent a detection time interval or a sampling rate or a sampling period. The time interval t2-t1 may define an activity detection time interval, and the time interval t2-t3 may define an inactivity detection time interval. As shown in FIG. 2, the inactivity time interval is much longer than the activity time interval. During the inactivity detection time interval, power consumption of the impedance sensing circuit is minimized.

[0049] Pulsing the impedance sensing circuit 14 during the activity detection time intervals, i.e., between time intervals t2 and t1 or between time intervals t4 and t3, serves to reduce the power consumption of the impedance sensing circuit as a whole. In this way, the power consumption of the wireless proximity detector array as well as the battery life of the battery 60 of the corresponding electronic device 80 can be extended or increased.

[0050] 8 thus illustrates a schematic spatial evolution of the complex reflection S11, which reflects the complex impedance of the antenna 12. In this case, along the direction y, the real part of S11 is provided. Along the direction x, the imaginary part of the reflection coefficient S11 is reflected. In the vertical direction, the spatial evolution distance in centimeters (cm) between the antenna 12 and the object 11 is shown. Such a spatial evolution of the antenna impedance may indicate a characteristic position or movement pattern of the object 11 when it moves in the immediate vicinity of at least one antenna 12, i.e., in the near field.

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

[0052] The output signal of oscillator 20, which is connected directly to coupler 13 and therefore to antenna 12, is provided as an input to automatic gain controller 22. Typically, automatic gain controller 22 operates to provide a constant bias current or a constant bias voltage at the input of measurement oscillator 20. A respective control signal, e.g., in the form of a bias current or bias voltage, is measurable at fa of automatic gain controller 22 and directly indicates a measurable variation in antenna impedance. This mode of operation of the automatic gain controller is immediately apparent from FIG. 4.

[0053] Instead of the automatic gain controller 22, an amplitude detector 24 may be provided, as shown in FIG. 5. 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, e.g., by a constant drive or bias current. In this case, any modifications or fluctuations in the antenna impedance may cause a corresponding measurable change in the amplitude of the oscillation signal as 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 directly operable to quantitatively measure any variations in the amplitude of the output signal of the measurement oscillator 20, which variations are typically induced by object movement-induced variations or modifications in the antenna impedance. Accordingly, the output fa′ of the amplitude detector directly indicates the real part of the reflection coefficient S of the antenna impedance.

[0054] The block diagrams according to Figures 6 and 7 show two alternative approaches to measuring the complex part of the reflection coefficient S11, which represents the antenna impedance. In the example of Figure 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 the phase comparator 27 with a well-defined reference frequency signal.

[0055] The phase comparator 27 is operable to determine and / or measure the phase difference between the oscillations of the measurement oscillator 20 and the oscillations of the reference frequency generator 28. A corresponding comparison signal as generated by the phase comparator 27 is provided to the loop filter 23, which generates a corresponding frequency control signal, e.g., a frequency control voltage, that is used to drive or bias the measurement oscillator 20. The loop filter 23 thus provides a control signal or bias signal fb that is directly indicative of the imaginary part of the reflection coefficient S11 of the antenna impedance.

[0056] As an alternative to the solution shown in FIG. 6 , a frequency counter 29 may be further provided, connected to the output 21 of the measurement oscillator 20, and operable to directly measure variations in the frequency of the measurement oscillator 20, which 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, e.g., by setting the input 34 to logic 1, the frequency counter 29 begins counting. Typically, the count enable input 34 is active for a well-defined and fairly precise time interval and at a certain time during that time interval, thereby allowing any variations in the frequency of the measurement oscillator 20 to be directly measured. From the measurable variations in the frequency and / or phase of the oscillations 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 a controller 30 which is operable to map each signal to a predetermined movement pattern in space and time of the object 11, for example relative to the at least one antenna 12.

[0058] As further shown in Figure 10, a method is provided for detecting and / or quantitatively measuring the movement in space and time of an object 11, e.g., a user's hand or finger, relative to a wireless proximity detector array 10. Here, in a first step 100, the wireless proximity detector array 10 is provided. In step 102, the impedance sensing circuitry 14 of the wireless or contactless proximity detector array 10 is activated for a predetermined time interval. Thereafter, while activated, in step 104, quantitative measurements of variations in antenna impedance are made by the impedance sensing circuitry 14 over time.

[0059] Thereafter, in step 106, the impedance sensing circuit 14 is deactivated for a predetermined time interval. The method may then continue with step 108, where the impedance sensing circuit 14 remains inactive. In this case, the controller 30 may simply count until the predetermined time interval has elapsed. The procedure then returns to step 102, where the impedance sensing circuit 14 is reactivated. The impedance measurements made during step 104 may be directly evaluated or further processed by the controller 30 to assign or map the measurement signals to predetermined spatiotemporal movement patterns of the object 11 relative to the antenna 12. Periodically deactivating the impedance sensing circuit 14 helps to conserve energy and extend battery life. [Explanation of symbols]

[0060] 10 Proximity detector array 11 Object 12 Antenna 13 Coupling device 14 Impedance detection circuit 15 Control Input 20 Oscillators 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 Controllers 31 Output 32 Neural Networks 33 Reset input 34 Counting permission input 35 Digital Storage 50 User Interface 60 batteries 80 Electronic equipment fa Real part of antenna impedance fa' Amplitude detector output fb Imaginary part of the antenna impedance SC control signal S11 complex reflection coefficient t0, t1, t2, t3, t4 times x,y direction

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) for a predetermined time interval; Equipped with the impedance detection circuit (14) comprises a measurement oscillator (20) coupled to the antenna (12), and the variation in the antenna impedance is quantitatively measurable by measuring at least one of a control signal for operating the measurement oscillator (20), an amplitude signal of the measurement oscillator (20), and a frequency signal of the measurement oscillator (20); The measurement oscillator (20) is coupled to an automatic gain controller (22) operable to restore the signal amplitude of the measurement oscillator (20). A wireless proximity detector array (10).

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 automatic gain controller is operable to provide an amplitude-controlled bias current to the measurement oscillator, the amplitude-controlled bias current undergoing measurable variation in response to the variation in the antenna impedance.

4. 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) for a predetermined time interval; Equipped with the impedance detection circuit (14) comprises a measurement oscillator (20) coupled to the antenna (12), and the variation in the antenna impedance is quantitatively measurable by measuring at least one of a control signal for operating the measurement oscillator (20), an amplitude signal of the measurement oscillator (20), and a frequency signal of the measurement oscillator (20); The impedance sensing circuit (14) comprises an amplitude detector (24) connected to the output of the measurement oscillator (20).

5. 5. The wireless proximity detector array (10) of claim 4, wherein the measurement oscillator (20) is operable with a constant bias current, and the amplitude detector (24) is operable to measure variations in signal amplitude of the measurement oscillator (20) in response to the variations in the antenna impedance.

6. 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) for a predetermined time interval; Equipped with the impedance detection circuit (14) comprises a measurement oscillator (20) coupled to the antenna (12), and the variation in the antenna impedance is quantitatively measurable by measuring at least one of a control signal for operating the measurement oscillator (20), an amplitude signal of the measurement oscillator (20), and a frequency signal of the measurement oscillator (20); The impedance sensing circuit (14) comprises a phase locked loop (26) coupled to the measurement oscillator (20) and to a reference frequency generator (28).

7. 7. The wireless proximity detector array (10) of claim 6, 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).

8. 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) for a predetermined time interval; Equipped with the impedance detection circuit (14) comprises a measurement oscillator (20) coupled to the antenna (12), and the variation in the antenna impedance is quantitatively measurable by measuring at least one of a control signal for operating the measurement oscillator (20), an amplitude signal of the measurement oscillator (20), and a frequency signal of the measurement oscillator (20); A wireless proximity detector array (10) wherein the impedance sensing circuit (14) comprises a frequency counter (29) connected to the output of the measurement oscillator (20).

9. 9. The wireless proximity detector array (10) of claim 8, 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.

10. 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) for a predetermined time interval; Equipped with the impedance detection circuit (14) comprises a measurement oscillator (20) coupled to the antenna (12), and the variation in the antenna impedance is quantitatively measurable by measuring at least one of a control signal for operating the measurement oscillator (20), an amplitude signal of the measurement oscillator (20), and a frequency signal of the measurement oscillator (20); A wireless proximity detector array (10) wherein the impedance sensing circuit (14) is operable to drive the measurement oscillator (20) in a spread spectrum mode.

11. 11. 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) being operable to store numerous time evolutions of impedance signals, and the neural network (32) being 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).

12. An electronic device (80) comprising a user interface (50) for controlling or modifying functions of the electronic device (80), the user interface (50) comprising a wireless proximity detector array (10) according to any one of claims 1, 4, 6, 8 and 10.

13. 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 the impedance sensing circuitry (14) of said wireless proximity detector array (10) for a predetermined time interval; c) quantitatively measuring the variation of antenna impedance over time by measuring the control signal for operating the measurement oscillator (20) coupled to the automatic gain controller (22) in the impedance sensing circuit (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.

14. 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 4; b) activating the impedance sensing circuitry (14) of said wireless proximity detector array (10) for a predetermined time interval; c) quantitatively measuring the variation of antenna impedance over time by measuring the amplitude signal of the measurement oscillator (20) connected to the amplitude detector (24) in the impedance sensing circuit (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.

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 6; b) activating the impedance sensing circuitry (14) of said wireless proximity detector array (10) for a predetermined time interval; c) quantitatively measuring the variation of antenna impedance over time by measuring the control signal for operating the measurement oscillator (20) coupled to the phase-locked loop (26) in the impedance sensing circuit (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.

16. 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 8; b) activating the impedance sensing circuitry (14) of said wireless proximity detector array (10) for a predetermined time interval; c) quantitatively measuring the variation of antenna impedance over time by measuring the frequency signal of the measurement oscillator (20) connected to the frequency counter (29) in the impedance sensing circuit (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.

17. 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 10; b) activating an impedance sensing circuit (14) of the wireless proximity detector array (10) for a predetermined time interval, wherein the measurement oscillator (20) in the impedance sensing circuit (14) is driven in a spread spectrum mode; 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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