METHOD AND SYSTEM FOR NON-CONTACT GESTURE RECOGNITION AND LEVEL AND TOUCH DETECTION

Abstract

Sensor system combining a first detection system (410) and a second detection system (420); wherein the sensor system is configured to provide control signals to electrodes of the first detection system (410) and the second detection system (420), the control signals having a control sequence consisting of a repetition of an elementary detection cycle, each elementary detection cycle having two successive main phases (P1, Q1; P2, Q2), wherein the sensor system is configured to control a node A, coupled to at least one electrode of the first detection system (410), to a first electrical potential (Vdd, VVE_high) during a pre-charging phase (P1) of the first main phase (P1, Q1) for at least some time during the pre-charging phase (P1) of the first main phase (P1, Q1), and to control a node A, coupled to at least one electrode of the first detection system (410), to a first electrical potential (Vdd, VVE_high) during a detection phase. (Q1) of the first main phase (P1, Q1),to control node A to a first intermediate electrical potential (VVE_low) for at least some time during the detection phase (Q1) of the first main phase (P1, Q1), and to control node B, which is coupled to at least one electrode of the second detection system (420), to a second electrical potential (Vdd) for at least some time during the pre-charging phase (P1) of the first main phase (P1, Q1), and then to switch node B to high impedance at direct current for at least some time during the detection phase (Q1) of the first main phase (P1, Q1), and wherein during a second main phase (P2, Q2) the sensor system is configured to control node A to a third electrical potential (Vss, VVE_low) for at least some time during a pre-charging phase (P2) of the second main phase (P2, Q2), and to control node B during a detection phase (Q2) of the second main phase (P2,Q2) to control node A to a second intermediate electrical potential (VVE_high) for at least some time during the detection phase (Q2) of the second main phase (P2, Q2), and to control node B to a fourth electrical potential (Vss) for at least some time during the pre-charging phase (P2) of the second main phase (P2, Q2), and then to switch node B to high impedance at direct current for at least some time during the detection phase (Q2) of the second main phase (P2, Q2), wherein the first detection system (410) is further configured to perform an electrical measurement at node A, and wherein the second detection system (420) is further configured to perform an electrical measurement at node B.

Description

RELATED PATENT APPLICATION

[0001] This application claims precedence over serial number 62 / 637,002 of the jointly owned preliminary US patent application; filed on March 1, 2018; entitled “Method and system for non-contact gesture detection and hover and touch detection” and is hereby incorporated for all purposes by reference herein. TECHNICAL AREA OF INVENTION

[0002] The present disclosure relates to human-machine interfaces, in particular to a method and a system for gesture detection and for hover and touch detection. BACKGROUND OF THE INVENTION

[0003] The integrated circuit “GestIC®”, also known as MGC3130, manufactured by the applicant of this application, is a highly sensitive capacitive sensor technology used for non-contact gesture detection using an alternating electric field, for example, at 40 to 250 kHz. Human-machine interface (HMI) devices that use capacitive sensing have sensor electrodes that are often formed in layers of conductive material, such as copper strips from printed circuit board (PCB) or indium tin oxide (ITO) on glass. These electrodes are electrically connected to a gesture detection unit, for example, on the same circuit board or on a separate board.The measurement value of the gesture detection unit depends, among other things, on the position of a target object (finger / hand) near the sensor electrode. This position influences the capacitive coupling between the electrode and the target, generating a target measurement signal based on the distortion of the alternating electric field. Gestures are performed over a detection area without touching any part of the device.

[0004] Typically, an additional touch detection sensor device is used to precisely determine a point of contact. Touch detection generally cannot be performed using 3D coordinates, particularly the vertical distance provided by the 3D detection system. Since such a system, for example, detects a disturbance in the generated electric field to produce 3D position data, it identifies a location within an object, such as its center of gravity or mass. Therefore, contact with another part of the object can occur while a certain distance in the vertical direction is still greater than zero. For this purpose, due to the difference between the detection systems, multiplexing between a pure touch detection system and a 3D detection system is generally used.US patent application US2016 / 0261250A1 discloses an example of such a time-division multiplexing system, to which reference is hereby made in its entirety.

[0005] Fig. Figure 1 shows a typical 2D / 3D gesture / touch detection system 100, available from the applicant of the present application, which performs 2D and 3D scans in a time-division multiplexing manner. Such a system includes a touch grid. 150 and four receiving electrodes 110-140 The touch grid can also function as a transfer electrode when working in 3D mode. Such a system can be used as in Fig.Figure 1a shows operating with multiplex periods of, for example, 12 ms duration, where 2D scanning is active for a 2 ms time slot and 3D scanning is active for the remaining 10 ms time slot, while the 2D electrode grid 150 is driven with a transmission signal Tx to support the 3D scanning. That is, time-division multiplexing is performed, where channel access alternates between 2D and 3D scanning, and each time slot for 2D or 3D scanning has a multitude of element capture cycles, as explained in more detail below. If a touch is detected during the 2 ms 2D scanning time window, the system switches to a 2D-only mode until no further touch is detected, i.e., the touch is released, and multiplexing between 2D and 3D scanning resumes. This is in the flowchart of Fig. 9 shown.

[0006] However, such multiplexing typically has a high maximum delay for first-touch detection. While the system is in 3D scan mode, a touch on the 2D grid cannot be detected. For the reasons explained above, such a touch can only be detected once the system returns to 2D touch detection mode. Therefore, this solution introduces an additional delay of up to 10 ms for first-touch detection compared to a 2D-only system with 100% scan time.

[0007] While a system is operating in one of the two operating modes, no data is acquired for the other operating mode. This directly reduces the received signal energy. For example, for the configuration above, the 3D measurement sensitivity is reduced to (10 ms / 12 ms) = 83% compared to a 3D-only system.

[0008] Furthermore, multiplexing also reduces the noise reduction capability for 3D scans. The lack of temporal continuity in data acquisition diminishes the ability of digital filters, such as low-pass filters, to suppress energy at frequencies where only noise, but no signal, is present. Fig.Figure 19 shows the 3D-GestIC® susceptibility to single-tone noise—considering only digital filtering—for a carrier frequency of fTx = 100 kHz. A sampling frequency of 2 * fTx = 200 kHz and downsampling to 1 kHz are assumed. Two out of twelve samples at 1 kHz are periodically discarded, as reflected in the puncture pattern PP = [0 0 1 1 1 1 1 1 1 1 1 1]. The lower graph shows a zoom into the upper graph around the carrier frequency. We observe that the susceptibility to noise increases significantly, most notably near the carrier frequency (as well as odd multiples thereof, not shown in the figure), where new side peaks appear for the time-division multiplexing case, well above -60 dB, even when more than 1 kHz away from the carrier frequency. A reduced noise reduction capability directly implies a reduced detection range in noisy environments.

[0009] Furthermore, the noise reduction capability for 2D scans is reduced. To maximize the capture area and noise robustness during 3D scanning, the 3D scan time is increased from 12 ms to 10 ms, resulting in a 2D scan time of only two milliseconds. This scan time is sufficient only to detect an initial touch, but not to perform noise-resistant hover position tracking. SUMMARY

[0010] There is a need for a capacitive detection system for multi-finger 2D touch detection, including hover detection, i.e., near-field detection (<5cm) and tracking of one or more fingers, as well as medium-range or 3D (~5 to 20cm) position tracking and gesture detection.

[0011] According to one embodiment, a sensor system can combine a first detection system and a second detection system, wherein the sensor system is configured to provide control signals to electrodes of the first detection system and the second detection system, wherein the control signals comprise a control sequence consisting of a repetition of an elementary detection cycle, wherein each elementary detection cycle has two successive main phases, wherein during a first main phase the sensor system is configuredto control a node A coupled to at least one electrode of the first detection system to a first electrical potential for at least some time during a pre-charging phase of the first main phase, and to control node A to a first intermediate electrical potential for at least some time during a detection phase of the first main phase, and to control a node B coupled to at least one electrode of the second detection system to a second electrical potential for at least some time during the pre-charging phase of the first main phase, and then to switch node B to high impedance at direct current for at least some time during the detection phase of the first main phase.and wherein, during a second main phase, the sensor system is configured to control node A to a third electrical potential for at least some time during a pre-charging phase of the second main phase, and during a detection phase of the second main phase, to control node A to a second intermediate electrical potential for at least some time during the detection phase of the second main phase, and to control node B to a fourth electrical potential for at least some time during the pre-charging phase of the second main phase, and subsequently to switch node B to a high impedance DC current for at least some time during the detection phase of the second main phase, wherein the first detection system is further configured to perform an electrical measurement at node A, and wherein the second detection system is further configured to perform an electrical measurement at node B.

[0012] According to a further embodiment, a method for combining a first detection method and a second detection method can comprise: supplying control signals to electrodes, wherein the control signals have a control sequence consisting of a repetition of an elementary detection cycle, each elementary detection cycle (EAC) consisting of two successive main phases, wherein during a first main phase, a node A coupled to at least one electrode is controlled to a first electrical potential for at least some time during a pre-charging phase of the first main phase, and node A is controlled to a first intermediate electrical potential for at least some time during a detection phase of the first main phase, and node B is controlled to a second electrical potential for at least some time during the pre-charging phase of the first main phase.The potential is controlled, and then node B is switched to high impedance with direct current for at least some time during the detection phase of the first main phase, and during a second main phase, node A is controlled to a third electrical potential for at least some time during the pre-charging phase of the second main phase, and during a detection phase of the second main phase, node A is controlled to a second intermediate electrical potential for at least some time during the detection phase of the second main phase, and node B is controlled to a fourth electrical potential for at least some time during the pre-charging phase of the second main phase, and then node B is switched to high impedance with direct current for at least some time during the detection phase of the second main phase, whereby an electrical measurement is carried out at node A and an electrical measurement is carried out at node B.

[0013] According to a further embodiment of the above sensor system or method, the first detection system can be further configured to perform an electrical measurement at node A while node A is being driven to the first or second intermediate electrical potential, wherein the second detection system is further configured to measure an electrical potential at node B that is reached after node B has been switched to a high-impedance DC current. According to a further embodiment of the above sensor system or method, the first intermediate electrical potential can be lower than the first electrical potential, and the second intermediate electrical potential can be higher than the third electrical potential.According to a further embodiment of the above sensor system or method, the first electrical potential can be higher than the second intermediate electrical potential, and the third electrical potential can be lower than the first intermediate electrical potential. According to a further embodiment of the above sensor system or method, the first electrical potential can be equal to the second intermediate electrical potential, and the third electrical potential can be equal to the first intermediate electrical potential. According to a further embodiment of the above sensor system or method, the sensor system can be configured during each pre-charging phase, after a first time interval, to control node A to the first or third electrical potential during a second time interval, and during each sensing phase, to control node A to the second or first intermediate electrical potential, respectively, after a third time interval.According to a further embodiment of the above sensor system or method, the sensor system can be configured after the second time interval to switch node A into tristate. According to a further embodiment of the above sensor system or method, the sensor system can be configured during each pre-charging phase to control node B to the second or fourth electrical potential after a fourth time interval, during a fifth time interval, and then switch node B into tristate. It can also be configured during each sensing phase to maintain node B at high impedance under direct current. According to a further embodiment of the above sensor system or method, the first and second electrical potentials can be equal, and the third and fourth electrical potentials can also be equal.According to a further embodiment of the above sensor system or method, the time intervals in which node A is at the first or third electrical potential and node B is at the second or fourth electrical potential can overlap. According to a further embodiment of the above sensor system or method, the sensor system can be configured to keep node A at the first electrical potential during the pre-charging phase of the first main phase and to control node A to the first intermediate electrical potential during the sensing phase of the first main phase, and to keep node A at the third electrical potential during the pre-charging phase of the second main phase and to control node A to the second intermediate electrical potential during the sensing phase of the second main phase.According to a further embodiment of the above sensor system or method, each of the electrical nodes is galvanically coupled or connected to a port of an integrated circuit, each of these ports being connected to a terminal block of a chip assembly. According to a further embodiment of the above sensor system or method, node A can be used for touch and / or hover detection. According to a further embodiment of the above sensor system or method, node B can be used for mid-range position and gesture detection. According to a further embodiment of the above sensor system or method, analog-to-digital converters can perform the sampling during the sensing phases.According to a further embodiment of the above sensor system or method, the sensor system can be designed to detect the position of at least one object on, in front of, or near a touch panel. According to a further embodiment of the above sensor system or method, a carrier frequency, defined by switching between the first and third electrical potentials, can be between 1 kHz and 1000 kHz. According to a further embodiment of the above sensor system or method, the system can have one or more nodes A, and each node A is connected to electrodes of a touch panel. According to a further embodiment of the above sensor system or method, the system can have one or more nodes B, and at least one node B is connected to electrodes of a touch panel.According to a further embodiment of the above sensor system or method, the system can have one or more nodes A and at least one node B connected to electrodes of the second detection system, which are located near a touch panel. According to a further embodiment of the above sensor system or method, node A can be part of a first microcontroller for 2D touch and hover detection, and node B can be part of a second microcontroller for 3D mid-range position and gesture detection. According to a further embodiment of the above sensor system or method, nodes A and B can be part of a single microcontroller for combined 2D touch and hover detection and 3D position and gesture detection.According to a further embodiment of the above sensor system or method, the sensor system can enable a seamless transition between 3D mid-range position sensing, 2D hover position sensing, and touch position sensing. According to a further embodiment of the above sensor system or method, an electrode connected to node A can be used for touch and / or hover detection. According to a further embodiment of the above sensor system or method, an electrode connected to node B can be used for non-contact 3D position and / or gesture sensing. List of characters Fig. Figure 1 shows a 2D / 3D detection system that uses time-division multiplexing; Fig. 1a shows a time diagram for the system of Fig. 1; Fig. 2 shows a circuit diagram for measuring self-capacitance; Fig.Figure 3 shows a time diagram for a specific procedure for measuring intrinsic capacity; Fig. Figure 4 shows the point in time for pure 3D acquisition using CVD measurements; Fig. 5 shows a circuit diagram for measuring the self-capacitance according to one embodiment; Fig. 6 and Fig. 6a show time diagrams of embodiments according to the present application; Fig. 6b shows a circuit diagram for measuring the self-capacitance according to the one in Fig. Time diagram shown in 6a; Fig. Figure 7 shows a timing diagram of another embodiment, showing the superimposed 2D and 3D sampling cycles for nested acquisition; Fig. Figure 8 shows a timing diagram with a 2D terminal block control sequence when pre-loading on Vv. E_high and V VE_low is carried out according to a further embodiment. Fig.Figure 9 shows a simplified state diagram of conventional time-division multiplexing; Fig. Figure 10 shows a state diagram with conventional switches; Fig. 11 and Fig. Figure 12 shows embodiments with a 2D grid with horizontal and vertical electrodes (“conductors”) and a frame of four further electrodes; Fig. Figure 13 shows a further embodiment with a 2D grid having horizontal and vertical electrodes (“conductors”) and a segmented electrode near one side of the 2D grid; and Fig. Figure 14 shows a further embodiment with a 2D grid with horizontal and vertical electrodes (“conductors”), a segmented electrode near one side of the 2D grid and another electrode on the opposite side of the 2D grid; Fig. 15 to Fig. Figure 18 shows various other embodiments of sensor arrangements; and Fig. Figure 19 shows the noise susceptibility with and without time-division multiplexing. DETAILED DESCRIPTION

[0014] 2D touch detection systems have long been standard human-machine interfaces, for example in touch displays. Use cases for hover position tracking over such displays include highlighting the displayed context under the hand, such as in a context menu or taskbar. For example, a display using such an interface can show general information, and when a user's hand approaches the display and reaches a predefined distance, a pop-up menu can appear. Additionally, a finger can hover over the various menu buttons, which can be enlarged as the finger moves over them. Once an actual touch is detected, the corresponding button can be highlighted, its color changed, or a different function menu displayed.Exemplary use cases for 3D gesture detection include flick gestures for navigating a menu or switching audio tracks, as well as circular motion gestures for controlling audio volume. The demand for such features has been addressed particularly in the automotive market.

[0015] As discussed above, there are existing solutions for standalone 2D touch / hover detection, such as maXTouch® chips, and there are other existing solutions for standalone 3D detection in the mid-range, such as MGC3xxx GestIC® chips from Microchip Technology Inc. These systems use capacitive sensing. They generate a repeated electrical stimulus and measure its effect on a quantity measured at a sensing electrode. This quantity is amplitude-modulated by changes in the capacitive environment of the sensing electrode, particularly by the position-dependent capacitances of a finger or hand in this environment. The repetition frequency of this stimulus is called the carrier frequency and is typically in the range of 40 kHz to 250 kHz.In addition to this stimulus, a capacitive sensor system is typically configured to also execute periodic digital and / or analog drive and control sequences, which may or may not be directly measurable, for example, for input port switches, amplifiers, analog-to-digital converters (ADCs), or other front-end timings. One period of this set of simultaneous periodic stimuli and sequences is called an elementary sensing cycle (EAC); that is, an EAC itself is a non-periodic sequence.

[0016] Touch detection—especially the detection of the first touch—with a maXTouch® controller is typically performed using self-capacitance measurements. During these measurements, the sensing electrode is driven to the electrical potentials of the virtual earth (VE). Multiple electrodes of a sensor can be used simultaneously for such self-capacitance measurements. Furthermore, electrodes not currently being detected can be driven in the same way as the detected electrodes, thereby suppressing mutual capacitance effects on the measured data. This technique is known as "driven shielding."

[0017] Fig. Figure 2 shows an exemplary configuration for measuring the self-capacitance of a sensor electrode with a circuit that includes a switching unit. 240 , an integrator 220 and an associated ADC 230 The connection field 215and its connected sensor electrode 210 are pre-charged by either the switch S1 on Vdd or the switch S2 The circuit is switched to ground while S0 is open, and switch Sint is also closed to discharge the integrating capacitor Cint while S0 is open. Then, for a detection phase, all switches are opened, and then S0 is closed. This completes the connection panel. 215 and its connected electrode 210 on the VirtualEarth potential V VE controlled, and Cint integrates the charge moving to or from the sensor electrode. 210 moved. The process can be repeated by moving the sensor electrode. 210 is pre-charged to the opposite potential, ground or Vdd, and a different electrical VirtualEarth potential is used.

[0018] Fig.Figure 3 schematically shows a time course of the terminal voltage, i.e., the stimulus, during a self-capacitance EAC, which essentially consists of two main phases, each of which may have a pre-charging phase and a sensing phase. Thus, according to one embodiment, there are two pre-charging phases in an EAC. P1 , P2 , in which the connection field is controlled to a desired electrical potential, and two detection phases Q1 , Q2 , in which the connection field is controlled to other electrical potentials, the virtual earth potentials Vv E_high or V VE_low , and the amount of charge flowing to the terminal block is measured. This can be achieved, for example, by a circuit like the one shown in Fig. 2 shown or achieved by measuring the current of the respective control circuit. This is also shown in Table 1 with the pre-charging phase. P1 including sub-phases P1_A1, P1_A2 and P1_A3, the data collection phase Q1with the sub-phases Q1_A1 and Q1_A2, the pre-charging phase P2 including the sub-phases P2 A1 , P2_A2 and P2 A3, the recording phase Q2 with sub-phases Q2_A1 and Q2_A2 combined. Furthermore, in Table 1, we generalize the pre-charge voltage Vdd in sub-phase P1_A2 to V PC,high and the pre-charge voltage Vss or ground in the sub-phase P2_A2 to V PC,low Each terminal block to which a sensor electrode can be connected is galvanically linked to an electrical node of a circuit. We refer to an electrical node that is driven by a control sequence for virtual earth measurements as a Type A node or node A. As is known from the prior art, an electrical node is assumed not to represent a physical point in a circuit diagram, but essentially refers to anything that is galvanically coupled.

[0019] The control sequence is essentially the same for all 2D grid electrodes, i.e., horizontal and vertical electrodes of the grid. 150 in Fig. 1. However, typically only a subset of 2D electrodes is sampled. Typically, subsets of electrodes are sampled alternately, so that after one rotation cycle, each electrode has been sampled at least once. "Sample" or "sample" here refers to measuring the amount of electrical charge that occurs during the phases. Q1 or Q2 flows to or from a 2D electrode. Table 1: Pre-loading and acquisition phases Virtual Earth - Node A CVD node B Pre-charge (P1) P1_A1: indifferent P1_B1: indifferent P1_A2: Control on V PC,high P1_B2: Control on V B,high P1_A3 (optional): Tristate P1_B3: Tristate Acquisition (Q1) Q1_A1: indifferent Q1_B: high impedance @DC (capacitive reactance) Q1_A2: Control on V VE low not targeted Pre-charge (P2) P2_A1: indifferent P2_B1: indifferent P2_A2: Control on V PC,low P2_B2: Control on V B,high P2_A3 (optional): Tristate P2_B3: Tristate Acquisition (Q2) Q2 A1: indifferent Q2_B: high impedance @DC (capacitive reactance) Q2_A2: Control on V VE_high not targeted

[0020] Each phase or sub-phase corresponds to a time slot in the EAC, as in Fig. 3 shown. First, during the phase P1 the receiving pad on node A with its connected receiving electrode on V PC,high= Vdd controlled, and then during a so-called charge integration phase Q1 on V VE_low If controlled, then the connection field on node A is controlled during the phase P2 on V PC,low = Vss controlled, and then during a further charge integration phase Q2 on V VE_high The phases P1 and Q1 can together with the phases P2 and Q2The connection panel—or more precisely, the connected electrical node—can be set to tristate at any time, as long as the control states P1_A2, Q1_A2, P2_A2, and P2_A3 listed in Table 1 are maintained for at least some time in each corresponding time slot. The node state, i.e., whether the node is driven, high-impedance, or set to tristate during phases P1_A1, Q1_A1, P2_A1, and Q2_A1, does not affect the values ​​measured during the acquisition phases and is therefore described as "indifferent."

[0021] For 3D measurements, the MGC3140 GestIC® controller from Microchip Technology Inc. performs combined measurements of self-capacitance and mutual capacitance using so-called Capacitive Voltage Division (CVD) measurements; see also Application Note AN1478, published by the applicant of this application and hereby incorporated in its entirety by reference. While a self-capacitance measurement is being performed at an Rx sensing electrode, the electrical potential at an adjacent Tx electrode, which is connected to a Tx terminal block, is changed during the CVD sensing phase. Fig.Figure 4 schematically shows a time diagram of the Tx terminal field voltage, which essentially represents a second stimulus, the Rx (sensing) terminal field voltage, and the voltage across an internal capacitor during an EAC. As with virtual earth measurements, each terminal field to which a sensor electrode can be connected is galvanically connected to an electrical node of a circuit. We refer to an electrical node driven by a drive sequence for CVD measurements as a Type B node or node B. The drive sequence for an EAC on a node B, which can be connected to a CVD Rx terminal field and an electrode, is also listed in Table 1 in the column 'CVD - Node B': Essentially, the sequence consists of alternately driving the terminal field connected to node B with two voltages V. B,high and V B,low, to pre-charge and then set the terminal block to high resistance with direct current (DC), i.e., not to control the terminal block. In the example of Fig. 4 is V B,high = Vdd and V B,low = Vss. One possible implementation for high impedance at DC is to connect the terminal block to a capacitive reactance, for example, the sampling capacitor of an ADC. Setting the terminal block to high impedance at DC is performed during phases Q1_B and Q2_B for at least part of the time. According to another embodiment, the node can be operated in tristate or, for example, disconnected for some time slots during Q1_B and Q2_B.

[0022] Multiple nodes A and B can be implemented, and depending on the system, they can be evaluated in parallel or sequentially. For example, a 3D detection system can use four or more sensor electrodes, as in Fig. 11 to Fig. 18 with the electrodes 110 until 140 and 180 shown. These electrodes can be evaluated sequentially or in parallel according to various embodiments.

[0023] Fig. Figure 5 shows the main configuration for CVD self-capacitance measurements with a switching unit. 310 and an associated ADC 230 : when the Saperture switch of the switching unit 310 When opened, i.e., when switched off, the sensor electrode 210 with its own capacity C s against mass either on V dd or ground pre-charged, and the internal holding capacitor C Hold of the ADC 230 is pre-charged to the opposite electrical potential, i.e., to ground, when the sensor electrode 210 on V dd pre-charged and vice versa by closing the respective switches of the switching unit 310 on V ddand ground. After pre-charging, all switches of the switching unit are then activated. 310 The aperture switch is open and closed. Consequently, Vs must equal -V. Hold are held and therefore the charges move between C S and C Hold , in order to satisfy this equation. Then V Hold from the ADC 230 measured.

[0024] Assuming that these two systems could be operated independently for 2D and 3D acquisition, examples of desired sensor layouts are shown in Fig. 11 to Fig. 14 shown.

[0025] Fig. 11 and Fig. Figure 12 shows a standard rectangular touch panel with a 2D grid. 170 from horizontal and vertical conductive lines or electrodes, for example made of transparent indium tin oxide (ITO), for 2D touch and levitation position detection. Fig.Figure 11 additionally shows how the touch grid can be used for touch position detection and for proximity and 3D touch detection according to different embodiments. Fig. Figure 11 additionally shows a 2D touch detection circuit. 410 and a 3D gesture recognition circuit 420 with time-division multiplexing 430 During the 2D acquisition period, the 3D frame electrodes are 110 , 120 , 130 , 140 It is set to a constant electrical potential. During the 3D scanning process, the touch control switches off. 410 a set of 2D grid electrodes 170 to a 3D stimulus. This sentence could consist only of the columns, as in Fig. 11 shown. However, other embodiments can select only rows, a combination of certain columns and rows, or all column and row electrodes.

[0026] Fig.Figure 12 shows that n lines are used to create this grid. 170 with an evaluation circuit 190 to be connected according to one embodiment. Four frame electrodes are arranged around this touch panel. 110-140 Arranged to detect the position of an object above the touch panel up to, for example, 10 cm away from the touch panel surface. Due to its lower sensitivity and smaller detection range, the 2D touch detection system is typically used with the 2D electrode grid. 170 This layout works regardless of how the frame electrodes are controlled. The more sensitive 3D scanning with the frame electrodes 110 until 140 However, it could be of great benefit if the 2D sensor grid 170 This could serve to provide a Tx stimulus. As a counterexample, the 2D grid would have 170Assuming it is set to earth potential or direct current, it has a similar effect on the 3D measurements as an actually aimed finger, and this influence of the 2D grid 170 would partially or completely mask the effect of a finger on the measured values. In the example of the sensor layout in Fig. 12 would be the left and right frame electrodes 140 , 120 predominantly used to detect hand position in the x-direction, and the upper and lower electrodes 110 , 130would be used primarily to detect hand position in the y-direction. The control sequence for the 3D frame electrodes is listed in the right-hand column of Table 1 (“CVD - Node B”). The control sequence for the 2D grid electrodes is essentially the same for all 2D grid electrodes, as listed in Table 1 (“VirtualEarth - Node A”), and a subset of the 2D grid electrodes are controlled and sampled, while the remaining 2D grid electrodes are only controlled but not sampled or brought to a constant electrical potential.

[0027] Fig. Figure 13 shows an approach using four GestIC® electrodes 110a , 120a , 130a and 140a , which are next to an edge of the 2D grid 170 are arranged and allow for better 3D positioning in the x-direction, but not in the y-direction.

[0028] Fig. Figure 14 shows an approach using four GestIC® electrodes 110a until140a , which run along an edge of the 2D grid 170 are arranged, as well as an additional GestIC® electrode 180 , which is next to another edge of the 2D grid 170 is arranged.

[0029] Despite the fact that it would be desirable to use the 2D grid 170To use capacitive sensing to provide a stimulus during 3D acquisition, the aforementioned standalone solutions cannot simply be operated simultaneously in close proximity to each other: Both solutions perform capacitive sensing, and while the effects of such systems on their electrical environment are typically limited in range, once the systems are operated close together, they can be considered to be using the same physical channel. This further means that—unless the systems are properly designed for co-operation—each will perceive the other as a source of noise, which can impair or completely prevent performance.

[0030] Existing solutions to this problem, as explained in the Background section of the invention, implement two parallel systems, one for 2D touch detection and one for 3D mid-area detection. These two systems cooperate with time-division multiplexing to share the channel resource, meaning that only one of the two systems is actually detecting at any given time. This represents a performance trade-off for each system in terms of response time, sensitivity, noise resistance, and electromagnetic emissions.

[0031] According to various embodiments, for the 2D self-capacitance sensing of the virtual earth, the electrical nodes, which are connected via chip connection fields to one or more sensing electrodes of a 2D electrode grid, are driven during the sensing phase, thereby changing the electrical potential of the nodes from a higher level to a lower level (phase).Q1 ) is changed or vice versa (phase Q2 This control of the electrical node and its connected electrodes can be used as a Tx stimulus for 3D-GestIC® measurements at the frame electrodes, see ‘3D Tx’ in Fig. 4. Consequently, the carrier frequencies for 2D and 3D acquisition must be adjusted. The 2D electrodes, which are not currently being acquired, can still be driven with the same stimulus, so that the signal transmitted through the 2D grating can be used. 170 The excited electric field – which influences the measured values ​​of the 3D frame electrodes – is independent of which of the 2D electrodes of the 2D grid is used. 170The data can be acquired at a single point in time. This has the advantage that the evaluation of the 3D frame electrode measurement data can be performed completely independently of the 2D acquisition, since the 3D measurement is only influenced by the external appearance of the 2D grid, i.e., how the 2D electrodes are activated, and not by the internal 2D signal processing. Furthermore, activating even the electrodes that are not currently being acquired results in the aforementioned effect of suppressing the influence of mutual capacitance between the activated electrodes.

[0032] Since this approach allows self-capacitance measurements to be performed on the 2D grid electrodes for up to 100% of the time, they are not limited by time-division multiplex 3D scanning as in the prior art solution, and there is no additional delay for the detection of the first touch.

[0033] A first example of a resulting control and acquisition sequence is shown in the timing diagram of Fig. Figure 6 shows, which also includes notes on the different timing phases and an EAC.

[0034] The signal '2D mXT Self-Cap - Node A' can be controlled in the same way as in a pure 2D touch sensing system (see Fig. 3) Simultaneously, 3D measurements can be performed by measuring the electrical potential, for example at the end of the acquisition phases. Q1 and Q2 can be obtained where the signal '2D mXT Self-Cap' is used as a Tx stimulus.

[0035] Fig. Figure 15 illustrates a standard rectangular touch panel 170 with a 2D grid of horizontal and vertical conductive sensor lines or electrodes and surrounding 3D Rx frame electrodes 110 until 140 Each of the electrodes is galvanically connected to a terminal block. 510connected, which itself is connected to an electrical node in a circuit 520 is connected.

[0036] Fig. Figure 16 illustrates a standard rectangular touch panel 170 with a 2D grid of horizontal and vertical conductive sensor lines or electrodes, some of which are permanently connected to electrical nodes of type A or type B, and some, for example, electrodes 530 , 540 and 560 , can be achieved through appropriate multiplexers 570 They can be multiplexed between nodes of type A or type B. As can be seen, each of the available electrodes could be permanently assigned to one of the 2D or 3D acquisition circuits. For example, to create a frame similar to the electrodes 110 until 140 from Fig. 15 instead of the electrode 540 to form the electrode 580The 3D scanning circuitry can be variably assigned. Any suitable fixed, configurable, or mixed configuration is possible according to the specific requirements of an application.

[0037] Fig. Figure 17 illustrates another embodiment with a standard rectangular touch panel. 170 with a 2D grid of horizontal and vertical conductive sensor lines or electrodes and surrounding 3D Rx corner electrodes 610 , 620 , 630 , 640 .

[0038] Fig. Figure 18 illustrates standard capacitive touch buttons 650 and a standard capacitive slide electrode arrangement 660 and 3D-Rx frame electrodes 110 until 140 .

[0039] Fig.Figure 10 shows a possible state diagram for switching between a) GestIC® mid-range position and gesture detection using measurement data, for example from frame electrodes, together with self-capacitance float detection from measurement data, for example from the 2D electrode grid, and b) a pure touch and float detection mode that is active as long as a touch of the 2D electrode grid is detected. Switching to the latter mode is only necessary upon initial touch detection and possibly for each type of calibration scan.

[0040] In an alternative implementation, 3D measurements are also performed while one or more contacts are being detected. For example, they are performed while self-capacitance measurements are carried out on the 2D electrode grid, which can be done repeatedly and alternately with measurements of mutual capacitance.

[0041] The pre-loading sub-phases P1_A2 and P1_B2, as well as P2_A2 and P2_B2, can have the same start time and / or the same stop time, but this is not required. For example, we see in Fig. 6, that P1_A2 begins before P1_B2 - the start of P1_B2 is when the 3D Rx terminal panel signal jumps to Vdd - and then P1_A2 and P1_B2 overlap for some time until P1_B2 ends, as in Fig. 6 specified, or P1_A2 ends (in Fig. 6 not visible). The following section presents non-preferred variants of the proposed approach, along with their advantages and disadvantages. Nested capture:

[0042] Table 1 shows the different phases or time slots of an EAC for 2D Virtual Earth (Node A) and 3D CVD measurements (Node B). In this preferred approach, according to various embodiments, both 2D and 3D acquisition occur during the phases. Q1 and Q2Alternatively, these two phases could also be used for 3D acquisition, with the “2D mXT Self Cap” signal only providing a stimulus for these 3D CVD measurements, i.e., the 2D lines during the phases Q1 and Q2 not be captured. Instead, 2D capture would take place during the extended phases P1_A1 and P2_A1. This is shown in the alternative time diagram of Fig. Figure 7 illustrates this. After the acquisition phases for 2D and 3D measurements have been separated in time, the signals on the electrodes that are not currently being acquired can be selected to support the current measurement. For example, the terminals for 3D acquisition could be set to a constant electrical potential during the 2D acquisition phase, as shown in Figure 7. Fig. 7 shown, or they could be at the same electrical potential as the connection fields for the 2D electrodes (in Fig.(7 not shown) can be controlled. This approach can be interpreted as nesting 2D and 3D measurements within an EAC, where the 2D grid or parts of it are driven with a Tx stimulus for 3D acquisition, while it is not used for 2D self-capacitance measurements. A potential drawback could be that this additional part of the stimulus increases the overall power consumption and electromagnetic emission compared to that in Fig. 6 preferred approaches increased.

[0043] Other potential drawbacks of this nested acquisition solution include: 1) Analog-to-digital conversion: The sampling time instances for 2D / floating measurements and 3D GestIC® are nested. This means that either the ADC timings for 2D / floating and 3D measurements must be controlled individually, or—for the common timing of all ADCs—each other resulting digital sample must be discarded; that is, the 2D / floating measurement sample is discarded while the 3D GestIC® measurement sample is retained, and vice versa. The latter would roughly double the ADC conversion speed requirements. Considering that, due to EMC limitations, the system is typically operated at 40 to 50 kHz, the resulting maximum sampling frequency would still only be 200 kHz.

[0044] 2) Signal settling time: Due to the interleaved measurements, the time available for signal adjustment is reduced compared to the preferred approach or a 2D / 3D-only system operating at the same carrier frequency. This can be relevant for larger displays with ITO electrodes and higher operating frequencies. However, higher carrier frequencies are not currently anticipated for the state-of-the-art approach, considering EMC limitations and the resulting selection of operating frequencies (40-50 kHz).

[0045] 2D VE self-capacitance measurements with pre-charge to V VE_high and V VE_low Instead of setting the 2D acquisition nodes to V during the pre-loading phases P1_A2 and P2_A2, respectively PC,high = Vdd and V PC,low In addition to controlling Vss, they can also be controlled by other electrical potentials. For example, they can be controlled by V PC,high = V VE_high and V PC,low = V VE_lowcan be controlled, for example in Fig. 8 shows where the electric potential during the phases P1 or P2 is constant. Since the nodes were already controlled to these voltages during the respective preceding acquisition phases, active control may not even be required, and the connection fields can alternatively be set in Tristate mode. This is in Fig. 6a further illustrates this. Fig. Figure 6b shows an exemplary system configuration for such measurements. In this embodiment, the integrator includes an operational amplifier configured as an integrator. 710 on, where the inverting input is connected to the sensor electrode 720 can be coupled and the non-inverting input can be selectively connected either to Vv E_high or V VE_low can be coupled.

[0046] 2D CVD self-capacitance measurements: Instead of the 2D sensor nodes during the phases Q1 and Q2 To actively control them, an alternative approach is to set them to a high impedance under DC current, similar to the 3D-CVD sensor nodes. Furthermore, the pre-charge potentials to which the connection fields are controlled during phases P1_A2 and P2_A2 could be used to improve sensitivity as V dd or V ss be elected.

[0047] To limit the number of sensing lines for 2D self-capacitance measurements while simultaneously performing medium-range 3D measurements—for example, due to a limited number of analog receive channels—two or more 2D sensing lines could be short-circuited to the same electrical node for sensing. When connecting adjacent lines, floating positioning should still be possible with sufficient accuracy if only a few lines, such as two or three, are connected. In the extreme case, all horizontal, all vertical, or all 2D sensing lines would be connected to a single 2D sensing node. This would, of course, no longer allow for 2D position estimation, but only proximity and (initial) touch detection. The capacitive load of the electrode grid would also be a factor. 170 would probably be a challenge for signal control.

[0048] The various embodiments offer a number of advantages over the prior art time-division multiplexing solution: The 2D response time for first touch remains as short as with a pure 2D touch detection system, meaning there would be no additional delay in detecting the first touch. Unlike the state-of-the-art approach, where 2D scans can only be performed for, say, 2 out of 10 ms, the proposed solution eliminates this limitation. First touch response time is crucial for both user experience and marketing—it's a key selling point.

[0049] With the current state-of-the-art solution, the 2D measurement time is very limited – it is only sufficient to achieve reliable detection upon initial contact. The proposed solution, due to time-division multiplexing, eliminates this time limitation, thus significantly improving the signal-to-noise ratio (SNR) of the 2D signals, enabling, for example, near-range hover detection. By combining position estimation at medium range using, for example, GestIC® with simultaneous 2D hover detection, a gradual transition between medium range (coarser resolution) and near range (finer resolution) becomes possible.

[0050] Electromagnetic emission is very important to customers. Both the state-of-the-art approach and the proposed approach provide an electrical stimulus 100% of the time. However, only the proposed approach ensures that the analog information generated by this stimulus is 100% accessible for both 2D and 3D acquisition. For example, the state-of-the-art approach only provides this access 83% of the time. Conversely, this means that with the proposed approach, we could reduce the amplitude of the stimulus signal and thus decrease emission while still achieving the same signal-to-noise ratio (SNR) as the state-of-the-art approach.

[0051] Improved noise immunity for 3D measurements: Digital low-pass filters typically expect input values ​​sampled at regular time intervals. Their filter performance degrades when samples are missing, as is the case with state-of-the-art time-division multiplexing (TDM) systems. With the proposed approach, data acquisition remains continuous, and therefore the noise suppression of the digital filter is equivalent to the case without TDM. Fig. 19.

[0052] Simplification of the overall acquisition system I: Since the acquired data appears as if it were obtained with a 2D-only or 3D-only system in higher-level algorithms, algorithmic advancements can be more easily distributed across a broader product range: A distinction between 2D-only / 3D-only systems and the proposed approach would become obsolete. This enables shorter development cycles.

[0053] Simplification of the overall acquisition system II: Typical capacitive acquisition systems use an adaptive frequency selection algorithm that allows switching to a different carrier frequency if the noise level at the current one is too high. Since both the 2D and 3D systems operate at the same carrier frequency in the proposed approach, only one algorithmic instance is required to find the best or a suitable carrier frequency.

[0054] The proposed approach utilizes maXTouch® silicon for 2D and 3D position and gesture detection. Furthermore, such a solution can support multi-stage virtual ground potentials, for example, by employing a 6-bit digital-to-analog converter. This allows for better optimization of the drive signal's shape during phases Q1_A1, Q2_A1 (and potentially also P1_A1 and P2_A1) to optimize electromagnetic emission. Regarding 2D detection performance, it is essential that the node potential decreases or increases substantially during Q1 and Q2, respectively, and ultimately reaches a defined value—as achieved by driving the nodes to specific stop values ​​during Q1_A2 and Q2_A2.

[0055] The electrodes of the 2D electrode grid can be connected to the same circuit as the GestIC electrodes, or they can be connected to one or more other circuits. In the latter case, a signaling connection must be established between the two or more circuits. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 2016 / 0261250 A1

[0004]

Claims

[1] Sensor system that combines a first detection system and a second detection system; wherein the sensor system is configured to provide control signals to electrodes of the first detection system and the second detection system, wherein the control signals have a control sequence consisting of a repetition of an elementary detection cycle, each elementary detection cycle having two successive main phases, wherein the sensor system is configured to control a node A, which is coupled to at least one electrode of the first detection system, to a first electrical potential during a pre-charging phase of the first main phase for at least some time during the pre-charging phase of the first main phase, and to control node A to a first intermediate electrical potential for at least some time during a detection phase of the first main phase, and to control a node B, which is coupled to at least one electrode of the second detection system, to a second electrical potential for at least some time during the pre-charging phase of the first main phase, and subsequently to switch node B to high impedance at direct current for at least some time during the detection phase of the first main phase, and wherein during a second main phase the sensor system is configured to control node A to a third electrical potential for at least some time during a pre-charging phase of the second main phase, and to control node A to a second intermediate electrical potential for at least some time during a detection phase of the second main phase, and to control node B to a fourth electrical potential for at least some time during the pre-charging phase of the second main phase, and then to switch node B to high impedance at direct current for at least some time during the detection phase of the second main phase. wherein the first detection system is still configured to perform an electrical measurement at node A, and the second detection system is further configured to perform an electrical measurement at node B. [2] Sensor system according to claim 1, wherein the first detection system is further configured to perform an electrical measurement at node A while node A is controlled to the first or second intermediate electrical potential, and wherein the second detection system is further configured to measure an electrical potential at node B, which is reached after switching node B to high impedance under direct current. [3] Sensor system according to one of claims 1 to 2, wherein the first intermediate electrical potential is lower than the first electrical potential and wherein the second intermediate potential is higher than the third electrical potential. [4] Sensor system according to one of claims 1 to 2, wherein the first electrical potential is higher than the second intermediate electrical potential and wherein the third electrical potential is lower than the first intermediate electrical potential. [5] Sensor system according to one of claims 1 to 2, wherein the first electrical potential is equal to the second intermediate electrical potential and wherein the third electrical potential is equal to the first intermediate electrical potential. [6] Sensor system according to one of claims 1 to 5, wherein the sensor system is configured to control node A to the first or third electrical potential during a second time interval during each pre-charging phase after a first time interval, and to control node A to the second or first intermediate electrical potential after a third time interval during each detection phase. [7] Sensor system according to claim 6, wherein the sensor system is configured to switch node A into tristate after the second time interval. [8] Sensor system according to any one of claims 1 to 7, wherein the sensor system is configured to control node B to the second or fourth electrical potential during each pre-charging phase after a fourth time interval during a fifth time interval and then to switch node B into tristate, and to keep node B high-impedance with direct current during each sensing phase. [9] Sensor system according to one of claims 1 to 2 or 6 to 8, wherein the first electrical potential and the second electrical potential are equal and wherein the third electrical potential and the fourth electrical potential are equal. [10] Sensor system according to claim 6, wherein a time interval in which node A is at the first or third electrical potential and in which node B is at the second or fourth electrical potential overlap. [11] Sensor system according to any one of claims 1 to 10, wherein the sensor system is configured to keep node A at the first electrical potential during the pre-charging phase of the first main phase, and to control node A to the first intermediate potential during the sensing phase of the first main phase and wherein during the pre-charging phase of the second main phase node A is held at the third electrical potential and during the acquisition phase of the second main phase node A is controlled to the second intermediate electrical potential. [12] Sensor system according to any one of claims 1 to 11, wherein each of the electrical nodes is galvanically coupled or connected to a port of an integrated circuit, wherein each of these ports is connected to a terminal array of a chip assembly. [13] Sensor system according to any one of claims 1 to 12, wherein node A is used for touch and / or levitation detection. [14] Sensor system according to any one of claims 1 to 13, wherein node B is used for position and gesture detection in the medium range. [15] Sensor system according to any one of claims 1 to 14, wherein analog-to-digital converters are configured to sample during the detection phases. [16] Sensor system according to any one of claims 1 to 15, wherein the sensor system is designed to detect the position of at least one object on, in front of or near a touch panel. [17] Sensor system according to any one of claims 1 to 16, wherein a carrier frequency defined by switching between the first and third electrical potential is between 1 kHz and 1000 kHz. [18] Sensor system according to any one of claims 1 to 17, wherein the system has one or more nodes A and each node A is connected to electrodes of a touch panel. [19] Sensor system according to any one of claims 1 to 18, wherein the system has one or more nodes B and at least one node B is connected to electrodes of a touch panel. [20] Sensor system according to any one of claims 1 to 17, wherein the system has one or more nodes A and at least one node B connected to electrodes of the second detection system located near a touch panel. [21] Sensor system according to one of claims 1 to 17, wherein node A is part of a first microcontroller for 2D touch and hover detection and node B is part of a second microcontroller for 3D position and gesture detection in the medium range. [22] Sensor system according to any one of claims 1 to 17, wherein nodes A and B are part of a microcontroller for joint 2D touch and hover detection and 3D position and gesture detection. [23] Sensor system according to claim 22, wherein the sensor system enables a seamless transition between 3D mid-range position detection, 2D floating position detection and touch position detection. [24] Sensor system according to any one of claims 1 to 17, wherein an electrode connected to node A is used for touch and / or levitation detection. [25] Sensor system according to one of claims 1 to 17 or 24, wherein an electrode connected to node B is used for non-contact 3D position and / or gesture detection. [26] Method for combining a first detection method and a second detection method, wherein the method comprises: Supplying control signals to electrodes, wherein the control signals form a control sequence consisting of a repetition of an elementary sensing cycle, each elementary sensing cycle (EAC) consisting of two successive main phases; wherein, during a first main phase, a node A coupled to at least one electrode is controlled to a first electrical potential for at least some time during a pre-charging phase of the first main phase, and, during a detection phase of the first main phase, node A is controlled to a first intermediate electrical potential for at least some time during the detection phase of the first main phase, and node B is controlled to a second electrical potential for at least some time during the pre-charging phase of the first main phase, and subsequently node B is switched to high impedance with direct current for at least some time during the detection phase of the first main phase, and wherein, during a second main phase, node A is controlled to a third electrical potential for at least some time during a pre-charging phase of the second main phase, and, during a detection phase of the second main phase, node A is controlled to a second intermediate electrical potential for at least some time during the detection phase of the second main phase, and node B is controlled to a fourth electrical potential for at least some time during the pre-charging phase of the second main phase, and afterwards node B is switched to high impedance with direct current for at least some time during the detection phase of the second main phase. Performing an electrical measurement at node A, and Performing an electrical measurement at node B. [27] Method according to claim 26, further comprising performing an electrical measurement at node A while node A is controlled to the first or second intermediate electrical potential, and measuring an electrical potential at node B that is reached after node B has been switched to high impedance with direct current. [28] Method according to one of claims 26 to 27, wherein the first intermediate electrical potential is lower than the first electrical potential and wherein the second intermediate potential is higher than the third electrical potential. [29] Method according to one of claims 26 to 27, wherein the first electrical potential is higher than the second intermediate electrical potential and wherein the third electrical potential is lower than the first intermediate electrical potential. [30] Method according to one of claims 26 to 27, wherein the first electrical potential is equal to the second intermediate electrical potential and wherein the third electrical potential is equal to the first intermediate electrical potential. [31] Method according to one of claims 26 to 30, wherein during each pre-charging phase, after a first time interval, node A is controlled to the first or third electrical potential during a second time interval, and during each detection phase, node A is controlled to the second or first intermediate electrical potential after a third time interval. [32] Method according to claim 31, wherein after the second time interval node A is switched to tristate. [33] Method according to one of claims 26 to 32, wherein during each pre-charging phase, after a fourth time interval, node B is controlled to the second or fourth electrical potential during a fifth time interval, and then node B is switched to tristate, and node B is held high-impedance with direct current during each detection phase. [34] Method according to one of claims 26 to 27 or 31 to 33, wherein the first electric potential and the second electric potential are equal and wherein the third electric potential and the fourth electric potential are equal. [35] Method according to claim 31, wherein a time interval in which node A is at the first or third electrical potential and node B is at the second or fourth electrical potential overlaps. [36] Method according to one of claims 26 to 35, wherein during the pre-charging phase of the first main phase the node A is held at the first electrical potential and during the detection phase of the first main phase the node A is controlled to a first electrical intermediate potential, and wherein during the pre-charging phase of the second main phase the node A is held at the third electrical potential and during the detection phase of the second main phase the node A is controlled to the second electrical intermediate potential. [37] Method comprising the operation of one of the sensor systems according to claims 1 to 25.