Control unit for an ultrasonic transducer and method for operating an ultrasonic transducer

Abstract

A control unit (1) for an ultrasonic transducer (100) comprises an excitation element (2) and a feedback element (3). The excitation element (2) is configured to apply a burst signal (11) to the ultrasonic transducer (100) to generate and transmit an ultrasonic signal (105). The excitation element (2) is further configured to apply an attenuation signal (12) to the transducer (100) to attenuate a periodic membrane displacement (4) after the transmission of the ultrasonic signal (105). The feedback element (3) is configured to generate the attenuation signal (12) by determining peak locations (41) of a membrane displacement (4) after the membrane excitation has ceased. The feedback element (3) is further configured to generate the attenuation signal (12) as a sequence of pulses such that each pulse is centered around a peak location (41).The feedback element (3) is configured to adaptively adjust the widths of the pulses of the damping signal (12) based on a factor of the absolute maximum or minimum values ​​of the membrane deflection (4). Furthermore, an ultrasonic transducer (100), a method for operating an ultrasonic transducer (100), a method for using an ultrasonic transducer (100), an electronic component, a computer-implemented method for operating a control device, a data processing device, a computer program and a computer-readable storage medium are specified.

Description

[0001] The disclosure relates to a control unit for an ultrasonic transducer and a method for operating such an ultrasonic transducer. Furthermore, the present disclosure relates to an ultrasonic transducer, a method for using an ultrasonic transducer, an electronic component, a computer-implemented method for operating a control unit, a data processing device, a computer program, and a computer-readable storage medium.

[0002] Piezoelectric ultrasonic transducers are typically used for both transmitting and receiving ultrasonic signals. Such transducers can be used as distance sensors, for example, in motor vehicles. However, these transducers usually continue to emit ultrasound even after the initial excitation of the ultrasonic signal has ceased. This is primarily due to a continuous movement of the diaphragm, also known as after-vibration. In general, after-vibration hinders the transducer's detection of a reflected ultrasonic signal because the diaphragm's after-vibration overlaps with the diaphragm displacement caused by the incoming ultrasonic signal.

[0003] Document US 4,580,251 describes an ultrasonic transducer in which the housing is adapted to dampen any ring-down upon receiving the reflected ultrasonic signal. Documents US 6,731,596 B2, GB 2,593,477 A, and LIU, Xinxin[ua]: Reducing ring-down time of pMUTs with phase shift of driving waveform. In: Sensors and Actuators A: Physical, Vol. 281, 2018, pp. 100–107. ISSN 0924-4247(P); 1873-3069(E). DOI: 10.1016 / j.sna.2018.08.039, describe ultrasonic transducers and methods for operating them in which ring-down is dampened.

[0004] Ultrasonic transducers and methods for operating them, in which ringing is reduced by damping, are also known from publications JP 2022 - 73 087 A and DE 10 2010 039 017 A1.

[0005] One task to be solved is to specify a control unit that enables an improved ultrasonic transducer, in particular improved distance measurement. Another task to be solved is to specify a method for operating such an improved ultrasonic transducer, in particular improved distance measurement.Other tasks to be solved include, among others, the specification of an ultrasonic transducer comprising such a control unit, a method for using such an ultrasonic transducer for distance measurement, an electronic component comprising such a control unit, a computer-implemented method for operating such a control unit, a data processing device comprising means for carrying out the computer-implemented method, a computer program comprising instructions enabling a computer to carry out the computer-implemented method, and a computer-readable storage medium for storing the computer program.

[0006] These problems are solved, among other things, by a control unit comprising the features of claim 1, or by a method comprising the features of claim 19. Further problems are solved, among other things, by an ultrasonic transducer comprising the features of claim 22, a method comprising the features of claim 23, an electronic component comprising the features of claim 24, a computer-implemented method comprising the features of claim 26, a device comprising the features of claim 27, a computer program comprising the features of claim 28, and storage media comprising the features of claim 29.

[0007] The control unit for an ultrasonic transducer includes an excitation element and a feedback element.

[0008] The excitation element is configured to apply a burst signal to the transducer in order to generate and transmit an ultrasound signal. The excitation element is further configured to apply an attenuation signal to the transducer in order to dampen any periodic diaphragm displacement following the transmission of the ultrasound signal.

[0009] The feedback element is configured to generate the damping signal by determining peak positions of a membrane displacement after the membrane excitation has ceased. The feedback element is further configured to generate the damping signal as a sequence of pulses, with each pulse centered around a peak position. The feedback element is also configured to adaptively adjust the widths of the damping signal pulses based on a factor of the absolute maximum or minimum values ​​of the membrane displacement.

[0010] In particular, the excitation element is designed to excite the transducer or a diaphragm of the transducer in order to generate and transmit an ultrasonic wave, which is the ultrasonic signal. This excitation induces a vibration or a periodic diaphragm displacement. The diaphragm is preferably in resonance and vibrates in a transmission mode. This transmission mode therefore has a relatively low power loss, which enables efficient generation of the ultrasonic signal.

[0011] The burst signal used to excite the transducer and generate the ultrasound signal is, for example, a sequence of pulses, preferably rectangular pulses. This burst signal is applied, for example, to a piezoelectric element of the transducer, which is configured to generate a mechanical movement from the electronic burst signal. In this case, the piezoelectric element can excite the diaphragm.

[0012] The damping signal is generated, in particular, by determining the peak positions of a membrane displacement signal, which is, in particular, an electrical or electronic signal corresponding to the membrane displacement. Using the membrane displacement signal, the membrane displacement can, for example, be analyzed, processed, and / or evaluated by software. Specifically, the peak positions of the membrane displacement can be determined by evaluating the membrane displacement signal.

[0013] Raw data of the attenuation signal is generated, for example, by the feedback element. The attenuation signal can then be derived from this raw data. Specifically, the raw data of the attenuation signal encompasses all the information related to the attenuation signal. Thus, in this case as well, the feedback element can generate the attenuation signal. For example, the feedback element is configured to generate the attenuation signal and store raw data of the attenuation signal for subsequent reconstruction.

[0014] During operation of the transducer, the transmitted ultrasound signal is reflected by an object whose distance is to be measured. The reflected ultrasound signal is detected by the transducer, preferably by the diaphragm, which is excited to vibrate by the incoming reflected ultrasound signal. The transducer converts the mechanical movement of the diaphragm into an electronic signal, in particular the diaphragm displacement signal, which can be processed, for example, by a digital signal processor to determine the distance to the object.

[0015] Since the reflected ultrasound signal typically has a lower intensity than the transmitted ultrasound signal, the membrane deflection induced by the reflected ultrasound signal is relatively small. Therefore, the reverberation must be efficiently damped to make the membrane sensitive to the reflected ultrasound signal.

[0016] To achieve this, the feedback element is configured to generate a damping signal. Preferably, the damping signal comprises a sequence of pulses, each pulse having a width and centered around a peak point of the diaphragm deflection. This means, in particular, that the pulses of the damping signal are applied to the diaphragm during the reverberation phase when the diaphragm deflection is at a peak point, i.e., a local minimum or maximum. This allows the damping signal to act particularly effectively on the diaphragm deflection, since the diaphragm has a comparatively low velocity at the peak points and is therefore sensitive to the pulses of the damping signal. This makes it possible to use the transducer for distance measurements where the object to be measured is located relatively close to the transducer.For example, the converter can efficiently detect objects that are less than 10 cm, less than 5 cm, or less than 4 cm away.

[0017] The adaptation of the damping signal pulses, hereinafter also referred to as damping pulses, to the peak positions is achieved in particular by the feedback element, which is configured to determine the peak positions of the diaphragm deflection, especially by means of the diaphragm deflection signal. Preferably, the peak positions are timestamps. This means, in particular, that the feedback element calculates and determines a temporal sequence of the damping pulses as a damping signal, so that the feedback element determines at what time a damping pulse is to be applied to the transducer or the transducer's diaphragm.

[0018] The control unit described here is advantageously designed to generate a damping signal using information, namely the peak positions of the reverberation, provided by the feedback element. This allows the damping signal to be generated relatively easily. For example, only a few electronic components, such as a processor, comparators, buffers, and a clock, are sufficient to determine the peak positions and generate the damping signal from them. Therefore, this control unit has relatively low hardware requirements.

[0019] Furthermore, the control unit and its functions can be implemented, at least partially, on an application-specific integrated circuit (ASIC), a microcontroller, a field-programmable gate array (FPGA), or similar device, optionally incorporating analog-to-digital converters for signal processing. Alternatively, the control unit and its functions can be implemented, at least partially, on a computer with suitable signal acquisition hardware. This allows for cost-effective manufacturing of the control unit and the converter. In particular, at least some steps of a control process performed by the control unit can be implemented as computer software executable on these devices.

[0020] Furthermore, generating the damping signal advantageously requires no optimization process or similar, but can simply be generated from peak points of the diaphragm displacement, for example, via the diaphragm displacement signal. This allows the damping signal to be obtained in a particularly short time. It is possible that simply observing the after-ringing is sufficient to identify the peak points and generate the damping signal from them.

[0021] This allows the damping signal to be easily and quickly adapted to changing environmental conditions. For example, changes in temperature, ambient pressure, or humidity can alter the transducer's resonant frequency and thus its transmission mode. Consequently, the damping signal may need to be adjusted to the new environmental conditions to effectively suppress ringing. Due to the short convergence time of the control unit described here, an adapted damping signal can be generated particularly quickly, making the transducer suitable for applications with varying environmental conditions, such as a distance sensor for vehicles. Furthermore, ambient noise can also be taken into account.

[0022] The damping signal can be adjusted, for example, using a closed-loop feedback method, where the adjustment is performed automatically within a closed control loop. In this case, the feedback element is preferably configured to automatically adjust the damping signal when a change in the vibration characteristic is detected, for example, due to a change in environmental conditions. Alternatively, open-loop adaptation of the damping signal is also possible.

[0023] Furthermore, the control unit and the procedures performed by the control unit described here can be used for existing converters with minimal adjustments, as expensive modeling and calibration can be avoided.

[0024] According to at least one embodiment of the control unit, the feedback element is further configured to monitor at least one vibration characteristic of the transducer's diaphragm during operation. For example, the vibration characteristic is monitored after the ultrasonic signal is emitted. This means, in particular, that the vibration characteristic is monitored when the damping signal is applied and / or during the diaphragm's after-vibration.

[0025] The feedback element is further configured to generate an adjusted damping signal when the vibration characteristic changes above a predefined threshold. Such a change in the vibration characteristic can occur, in particular, when the transducer's environmental conditions, such as temperature, pressure, or the like, change.

[0026] The vibration characteristic is, for example, an envelope function of the periodic membrane displacement, which can be represented by a measurable electrical signal. This envelope function corresponds to the amplitude of the measurable electrical signal, which in turn corresponds to the membrane displacement—that is, the membrane displacement signal. The envelope function is generated, for example, by digitizing raw data of the membrane displacement, such as the amplitude, and applying one or more digital filters. In particular, the envelope function corresponds to energy stored in a mode of the resonating membrane.

[0027] During normal operation of the transducer, distance measurements can be performed using the envelope function. For example, the transducer's envelope function is used as a baseline for calibration when no object is present. If an object is subsequently placed within the transducer's measuring range, the envelope function may deviate slightly from the baseline, indicating that the periodic diaphragm deflection has changed due to the object's reflected ultrasonic signal. Preferably, the distance to the object is determined from the envelope function deviation using a digital signal processor.

[0028] In particular, the threshold value is a means of distinguishing whether the change in the envelope function is caused by a change in the environmental conditions or by an object in the measurement range.

[0029] Preferably, the vibration characteristic, such as the envelope function, is monitored within a specific monitoring range. This monitoring range corresponds, for example, to a sub-range of the measuring range corresponding to small distances to the transducer, such as less than 5 cm. This monitoring range corresponds, in particular, to the diaphragm's reverberation time. Here and in the following, the diaphragm's reverberation time is defined as the period during which the diaphragm reverberates but no damping signal is applied.

[0030] Preferably, the adapted damping signal is generated by the feedback element when the envelope function changes in the monitoring area and the change is above the threshold.

[0031] It is possible for the adjusted damping signal to be generated as soon as the threshold is exceeded. It is also possible to calculate an average value from several threshold exceedances over multiple decay periods.

[0032] Preferably, the feedback element is configured to generate the adapted attenuation signal between the application of two successive burst signals to the transducer. In other words, the adapted attenuation signal is generated in one measurement cycle of the transducer, also referred to as a measurement acquisition.

[0033] A measurement is, in particular, the time interval between the excitation of the transducer to transmit the ultrasonic signal and the reception of the reflected ultrasonic signal. Specifically, during a measurement, the burst signal is applied to the transducer for an excitation period and the attenuation signal for an attenuation period. In other words, a measurement represents a time interval that includes the excitation period, the attenuation period, and the decay period. During transducer operation, for example, 15 measurement sessions per second can be performed.

[0034] According to at least one embodiment, the excitation element is configured to provide the burst signal and the attenuation signal in a common pulse sequence. This means, in particular, that the attenuation signal directly follows the burst signal.

[0035] According to at least one embodiment, the excitation element is configured to provide at least the damping signal in at least one positive state, at least one negative state, and at least one neutral state. For example, the damping signal in a positive state corresponds to a positive voltage value of the electrical damping signal.

[0036] For example, in a negative state, the damping signal corresponds to a negative voltage value of the electrical damping signal. Conversely, in the neutral state, the damping signal corresponds to a voltage value of the electrical damping signal that is essentially zero. The neutral state is achieved, in particular, by applying a high impedance to one output of the excitation element, so that essentially the entire voltage drops across the impedance.

[0037] In particular, the excitation element is configured to apply a pulse of the damping signal in the positive state when the corresponding peak position of the membrane displacement or membrane displacement signal is a local minimum. At this local minimum, the membrane displacement or membrane displacement signal exhibits a negative amplitude relative to a baseline of the membrane displacement or membrane displacement signal at which the membrane is at rest.

[0038] In particular, the excitation element is configured to apply a pulse of the damping signal in the negative state when the corresponding peak of the diaphragm displacement or diaphragm displacement signal is a local maximum. At this local maximum, the diaphragm displacement or diaphragm displacement signal exhibits a positive amplitude relative to the baseline of the diaphragm displacement or diaphragm displacement signal.

[0039] In particular, the excitation element is configured to apply the damping signal in the neutral state when the diaphragm displacement or the diaphragm displacement signal has a zero crossing. At the zero crossing point, the amplitude of the diaphragm displacement or the diaphragm displacement signal is essentially zero with respect to the baseline of the diaphragm displacement or the diaphragm displacement signal.

[0040] Preferably, the damping signal has a 180° phase shift relative to the periodic diaphragm displacement or the diaphragm displacement signal. Additionally or alternatively, the damping signal has a 180° phase shift relative to the burst signal.

[0041] Advantageously, the membrane deflection can be efficiently damped if the damping signal includes counter-pulses that counteract the membrane deflection at the peak points.

[0042] According to at least one embodiment, the control unit includes a clock generator configured to provide a clock signal, in particular based on the electronic signal of the diaphragm deflection. The peak positions are determined using the clock signal.

[0043] Preferably, the time resolution of the clock generator is at least ten times higher than the operating frequency of the ultrasonic transducer. For example, the operating frequency of the ultrasonic transducer is between 50 kHz and 100 kHz, for example 80 kHz. In this case, the time resolution is, for example, 1 ms. -1 .

[0044] The clock and clock signal provide, in particular, a temporal resolution for the control unit and / or for processes or computer-implemented procedures or algorithms, such as a control algorithm, executed by the control unit. The clock may also include a counter. For processing and / or storing the peak positions, timestamps generated by the clock are assigned to the peak positions and optionally stored. In this way, specific pulses of the damping signal can be advantageously assigned to specific peak positions of the diaphragm deflection.

[0045] According to at least one embodiment, the excitation element comprises a first intermediate memory configured to store raw data of the burst signal and the attenuation signal. For example, timestamps for pulses of the burst signal and / or the attenuation signal are stored in the first intermediate memory. Using the timestamps and the clock signal, a temporal sequence of pulses, which constitute the burst signal and / or the attenuation signal, can be generated.

[0046] Preferably, the excitation element comprises a signal generator which is configured to generate the burst signal and / or the attenuation signal as a temporal sequence of pulses using the raw data and the clock signal.

[0047] According to at least one embodiment, the feedback element is configured to determine peak positions of the membrane deflection by detecting zero crossings of the membrane deflection and calculating an average between two adjacent zero crossings. In particular, the feedback element is configured to determine peak positions of the membrane deflection by detecting zero crossings of the membrane deflection by sensing zero crossings of an electrical or electronic signal that is induced by and corresponds to the membrane deflection, i.e., the membrane deflection signal.

[0048] The zero crossing points are determined, for example, using a comparator and a clock signal. The comparator compares, for example, the membrane displacement signal corresponding to the membrane deflection with the zero point. Specifically, each time the comparator detects the membrane displacement signal as zero, a timestamp provided by the clock signal is assigned to define the zero crossing point of the membrane displacement. The membrane displacement signal is, for example, an electrical signal generated by the piezoelectric element based on the mechanical membrane displacement.

[0049] For example, if a first zero crossing is recorded at a time 10 arbitrary time units and a second zero crossing is recorded at a time 20 arbitrary time units, the corresponding peak point is approximately at a time 15 arbitrary time units.

[0050] By using a comparator to determine the zero crossing points and calculating the peak points from the zero crossing points, the peak points can be easily determined.

[0051] According to at least one embodiment of the control unit, the feedback element is configured to generate the damping signal such that it includes pulses with a width that is less than half a period of the periodic membrane deflection.

[0052] If the pulse is in a positive state, for example, the width indicates the duration for which the pulse remains in that positive state. If, for instance, we assume that half a period of the periodic membrane displacement includes a local minimum, and this period is the time interval between two zero crossings adjacent to the local minimum, then the corresponding pulse of the damping signal is in the positive state for a time interval equal to the width of the pulse centered around the local minimum, i.e., the peak location. At other times within that period, the damping signal is in the neutral state, meaning it is essentially zero.

[0053] If, for example, a first zero crossing is detected at a time of 10 arbitrary time units and a second zero crossing at a time of 20 arbitrary time units, the corresponding peak, i.e., the local minimum, occurs at approximately a time of 15 arbitrary time units. In this case, the width of the pulse, which is particularly in the positive state, is less than 10 arbitrary time units, since half the period of the periodic membrane displacement is 10 arbitrary time units.

[0054] It is possible that all pulses of the attenuation signal have the same width. However, it is also possible that different pulses of the attenuation signal differ in their width.

[0055] For example, it is possible that at least one or every pulse has a width that differs from all the widths of the other pulses in the attenuation signal. It is also possible that the attenuation signal comprises groups of pulses, each containing at least two pulses, where within each group all pulses have the same width and the widths of the pulses in different groups differ from each other.

[0056] By adjusting the pulse widths of the damping signal, it is advantageously possible to effectively dampen the diaphragm's after-vibration. In particular, it is possible to excite a damping mode for efficient energy dissipation by adjusting the pulse widths of the damping signal accordingly.

[0057] For example, the widths of the pulses of the damping signal can be adaptively adjusted based on a factor of the absolute maximum or minimum value of the membrane deflection in each time interval, i.e., each measurement recording.

[0058] According to at least one embodiment, the feedback element comprises an edge detection unit configured to determine the edge orientation of the periodic membrane deflection at a zero crossing point. In particular, the damping signal is adjusted depending on the edge orientation.

[0059] For example, at a specific zero crossing point, the edge of the membrane displacement signal corresponding to the membrane displacement is negative, meaning it has a negative gradient. In this case, the peak that precedes the zero crossing point is a local maximum, and the peak that follows the zero crossing point is a local minimum. Based on this information, the feedback element is specifically designed to generate the damping signal such that, relative to the specified zero crossing point, the damping signal exhibits a negative pulse at the position of the preceding peak and a positive pulse at the position of the subsequent peak.

[0060] For example, at another specific zero crossing point, the edge of the membrane displacement signal corresponding to the membrane displacement is positive, meaning it has a positive gradient. In this case, the peak preceding the zero crossing point is a local minimum, and the peak following the zero crossing point is a local maximum. Based on this information, the feedback element is specifically configured to generate the damping signal such that, relative to the specific zero crossing point, the damping signal exhibits a positive pulse at the position of the preceding peak and a negative pulse at the position of the subsequent peak.

[0061] According to at least one embodiment, the feedback element includes a second intermediate memory configured to store the peak positions and the edge orientation. It is also possible for the zero crossings to be stored in the second intermediate memory, allowing the peak positions to be calculated from the zero crossings as described above. In particular, the peak positions and / or zero crossings are stored as timestamps determined using the clock signal. For example, the peak position and / or the zero crossing and the associated edge orientation are stored as a pair of values ​​in the second intermediate memory. This data can be raw data of the attenuation signal from which the attenuation signal can be constructed.

[0062] It is also possible to store pulse widths in the second buffer. In this case, the peak location and / or the zero crossing location, the associated edge orientation, and the corresponding pulse widths can be stored as a triplet of values ​​in the second buffer.

[0063] Furthermore, the feedback element includes a processing unit configured to determine the damping signal based on the data stored in the second intermediate memory. Preferably, the processing unit is connected to the first intermediate memory and configured to store the generated damping signal in the first intermediate memory, so that the excitation element can apply the damping signal to the transducer.

[0064] It is possible that the second intermediate storage and the processing unit are implemented in a single component.

[0065] According to at least one embodiment, the excitation element for applying and / or the feedback element for generating the damping signal is configured to comprise a first part and a second part. The first part comprises pulses of a first type, and the second part comprises pulses of a second type. In particular, the pulses of the second type have a smaller width than the pulses of the first type. Preferably, the second part is applied following the first part. The width of the second type can be adaptively adjusted based on a factor of the absolute maximum or minimum value of the diaphragm deflection.

[0066] For example, the first part is a fixed portion of the damping signal. In this case, the first part is not adjusted when the damping signal is adjusted after a threshold-exceeding change in the vibration characteristic is detected. The second part, in this case, is preferably a variable portion of the damping signal, which is adjusted after a threshold-exceeding change in the vibration characteristic is detected. By adjusting only one portion of the damping signal, namely the second portion, the adjustment can be performed particularly quickly.

[0067] It is possible that the first part and the second part have the same amplitude. It is also possible that the first and / or second part has the same amplitude as the burst signal.

[0068] For example, the pulses of the first part of the damping signal each have a width corresponding to half a period of the periodic diaphragm deflection. In this case, the first part can correspond to the burst signal with a phase shift of 180°. This has the advantage that the energy of the transmit mode can be effectively dissipated. In this case, the second part is preferably configured to excite a damping mode different from the transmit mode, as described below. By exciting the first part before the second part, the excitation of the damping mode can be facilitated.

[0069] According to at least one embodiment, the pulses of the damping signal can vary in position, width, shape, energy, phase, and modulation. This means, in particular, that the excitation element for applying and / or the feedback element for generating the damping signal is configured such that the pulses of the damping signal can vary in position, width, shape, energy, phase, and modulation. Specifically, the pulses of the second type can vary in at least one of the aforementioned parameters.

[0070] According to at least one embodiment, the control unit is configured to excite a damping mode by applying the damping signal, which exhibits a higher energy dissipation than the transmit mode excited by applying the burst signal. The damping mode and / or the transmit mode are preferably stable modes or intrinsic modes of the transducer or the transducer diaphragm, or of a vibrating system of the transducer formed by the diaphragm together with a transducer housing.

[0071] In particular, the oscillating system and, further preferably, the housing of the transducer are adapted so that the transmit mode and the attenuation mode are stable.

[0072] Preferably, when the diaphragm vibrates in transmit mode, it is excited in a central region. More preferably, when the diaphragm vibrates in damping mode, it is also excited in peripheral regions surrounding the central region. In a top view of the diaphragm, these peripheral regions can form a ring or frame surrounding the central region. In particular, the peripheral regions are in contact with the housing, which advantageously enables high energy dissipation.

[0073] Furthermore, a method for operating an ultrasonic transducer is disclosed. The transducer comprises, in particular, a control unit described herein according to one or more of the embodiments described above. Thus, all features disclosed for the control unit are also disclosed for the method, and vice versa.

[0074] According to at least one embodiment, the method for operating an ultrasonic transducer comprises a step of exciting a diaphragm of the transducer to generate and transmit an ultrasonic signal by applying a burst signal to the diaphragm. In a subsequent step, the diaphragm is attenuated by applying an attenuation signal to the diaphragm. In particular, the attenuation signal is generated by determining peak locations of a diaphragm displacement after the excitation of the diaphragm has ceased, wherein the attenuation signal comprises a temporal sequence of pulses, each pulse being centered around a peak location. In particular, the attenuation signal is generated by determining peak locations of a diaphragm displacement signal, which is, in particular, an electrical or electronic signal corresponding to the diaphragm displacement.The membrane deflection can be analyzed, processed and / or evaluated, for example, by using software to analyze the membrane deflection signal.

[0075] For example, the attenuation signal follows directly after the burst signal. For example, the burst signal and the attenuation signal are provided together as a sequence of pulses.

[0076] According to at least one embodiment of the method, in a further step a vibration characteristic of the membrane is monitored and the damping signal is adjusted if the vibration characteristic changes above a predetermined threshold.

[0077] The vibration characteristic, for example, is an envelope function that corresponds to the amplitude of the membrane deflection.

[0078] A change in the vibration characteristics can be caused by a change in the environmental conditions surrounding the transducer. Such environmental conditions can include temperature, ambient pressure, or similar factors. Therefore, the transducer can be used in applications with fluctuating environmental conditions.

[0079] According to at least one embodiment of the method, the peak points of the membrane deflection are determined by detecting zero crossing points of the membrane deflection and calculating an average value between two adjacent zero crossing points.

[0080] Furthermore, an ultrasonic transducer is specified. The transducer comprises, in particular, at least one control unit described herein according to one or more of the embodiments described above. Therefore, all features disclosed for the control unit are also disclosed for the transducer, and vice versa.

[0081] In particular, when operating a transducer that includes a control unit as described herein, efficient damping of diaphragm resonance is possible. Thus, the ultrasonic transducer can be used for distance measurements where the distance to the object is less than 10 cm, preferably less than 5 cm or even less than 4 cm.

[0082] Furthermore, a measuring arrangement for measuring a distance to an object is specified. The measuring arrangement includes, in particular, a transducer described herein according to one or more of the embodiments described above. Therefore, all features disclosed for the transducer are also disclosed for the measuring arrangement and vice versa.

[0083] Preferably, the measuring arrangement comprises exactly one ultrasonic transducer, which includes a control unit as described herein. This means that the measurement of the object can be carried out with exactly one transducer for transmitting the ultrasonic signal and for receiving the reflected ultrasonic signal.

[0084] Furthermore, a method for using an ultrasonic transducer and / or a measuring arrangement for distance measurement is disclosed. The method for using an ultrasonic transducer and / or a measuring arrangement specifically utilizes a transducer and / or a measuring arrangement described herein according to one or more of the embodiments described above. Therefore, all features disclosed for the ultrasonic transducer and / or the measuring arrangement are also disclosed for the method for using an ultrasonic transducer and / or a measuring arrangement, and vice versa.

[0085] In particular, the distance between the transducer and the object to be measured is between 3 cm and 2 m inclusive. The distance is, for example, less than 10 cm, less than 6 cm, or less than 5 cm.

[0086] Furthermore, an electronic component is specified. The electronic component comprises, in particular, at least one control unit described herein according to one or more of the embodiments described above. All features disclosed for the control unit are therefore also disclosed for the electronic component, and vice versa.

[0087] The control unit is preferably part of an electronic component. The electronic component includes or is, for example, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a computer with means for signal generation and acquisition.

[0088] The control unit includes, for example, the excitation element, the feedback element, and the clock generator. A driver for generating an electronic signal from the damping signal and the burst signal, as well as the comparator, can be individual components of the electronic device. It is also possible that the driver and / or the comparator are part of the control unit.

[0089] The electronic component can further comprise an analog-to-digital converter (ADC) and at least one filter unit. The ADC and filter unit digitize the electrical signal supplied by the piezoelectric element, which corresponds to the membrane deflection, and process it for evaluation, for example, to perform a distance measurement. This evaluation can be carried out by a digital signal processor, which can be part of the electronic component or a separate, additional electronic component.

[0090] The electronic component is preferably part of the converter and is configured to control and regulate the converter. Optionally, the electronic component can evaluate measurement results from the converter.

[0091] Preferably, the electronic component can be used for various converters and applications. Thus, the control unit and the electronic component described herein are advantageously suitable for different converters, requiring little to no adaptation to these converters.

[0092] Furthermore, a computer-implemented method for operating a control unit is disclosed. In particular, the method is designed to operate a control unit described herein according to one or more of the embodiments described above. This means that all features disclosed for the control unit are also disclosed for the computer-implemented method, and vice versa.

[0093] According to at least one embodiment, the computer-implemented method comprises a step of providing the burst signal and the attenuation signal by reading raw data of the burst signal and the attenuation signal stored in the first intermediate memory, and generating the burst signal and the attenuation signal to be provided. For example, the burst signal and the attenuation signal are generated by the signal generator.

[0094] In a further step of the computer-implemented method, the raw data of the damping signal are generated by determining peak points of a diaphragm displacement signal. The diaphragm displacement signal corresponds in particular to the diaphragm displacement.

[0095] In particular, at least some of the steps performed by at least one part of the control unit, especially the first intermediate storage, the signal generator, the comparator, the edge detection unit, the arithmetic unit, the second intermediate storage, and a threshold unit, which were described above, for example, in connection with one or more embodiments of the control unit, the electronic component, or the method for operating a converter, can be executed by the computer-implemented method. Thus, preferably all the respective features of these elements disclosed above are also disclosed for the computer-implemented method.

[0096] In particular, the computer-implemented method includes a control algorithm with a closed control loop. Alternatively, the method can also include a fixed sequence as a control system with an open control loop.

[0097] In the case of a closed-loop control algorithm, the procedure includes a step to adjust the damping signal when, for example, a change in the vibration characteristic above a threshold is detected, as described above. The change in the vibration characteristic is, for example, the result of a change in environmental conditions. The change in the vibration characteristic above a threshold is specifically detected by the threshold unit. Such an adaptive closed-loop control approach has the advantage of being adaptable to any context and provides a beneficial control method for reducing the after-ringing of ultrasonic transducers and a method for operating such a transducer to increase the accuracy of distance measurement by reducing the minimum measurable distance.

[0098] Furthermore, a data processing device is described, which includes means for carrying out the computer-implemented method. The computer-implemented method can be executed on the data processing device. Therefore, all features disclosed for the computer-implemented method are also disclosed for the data processing device, and vice versa.

[0099] The data processing device can be a processor for a computer. The computer can further include suitable means, for example, hardware, for signal generation and acquisition. Alternatively, the data processing device can be part of, or an element of, a microcontroller, an application-specific integrated circuit (ASIC), or a field-programmable gate array (FPGA). The data processing device can, for example, be part of the electronic device or the control unit.

[0100] Furthermore, a computer program is disclosed. The computer program includes, in particular, instructions which, when executed by a computer, cause the computer to execute the computer-implemented method disclosed above. Therefore, all features disclosed for the computer-implemented method are also disclosed for the computer program, and vice versa. For example, the data processing device is part of the computer. The computer may include or be a microcontroller, an application-specific integrated circuit (ASIC), or a field-programmable gate array (FPGA), and / or preferably includes means configured for signal generation and acquisition.

[0101] Furthermore, a computer-readable storage medium is specified. In particular, the computer program described above is stored on the computer-readable storage medium. Therefore, all features disclosed for the computer-implemented method and the computer program are also disclosed for the computer-readable storage medium, and vice versa.

[0102] Further advantages and advantageous embodiments and developments of the control unit, transducer, measuring arrangement, method for operating a transducer, and method for using an ultrasonic transducer described herein will become apparent from the following exemplary embodiments, which are shown in conjunction with schematic drawings. Identical elements, similar elements, or elements with the same effect are designated with the same reference numerals in the figures. The figures and the proportions of the elements depicted in the figures are not to be considered as being to scale. Rather, individual elements may be exaggerated in size for better clarity and / or comprehensibility.

[0103] The figures show: Fig. Figure 1 shows a schematic illustration of an ultrasonic transducer described herein according to an exemplary embodiment; Fig. Figure 2 shows a block diagram illustrating a control unit for an ultrasonic transducer described herein according to a first embodiment; Fig. Figure 3 illustrates a change in the vibration modes of a transducer diaphragm caused by a damping signal according to the exemplary embodiment; Fig. Figure 4 shows a block diagram illustrating a control unit for an ultrasonic transducer described herein according to a second embodiment; Fig. Figure 5 shows a raw signal of an electronic signal corresponding to the amplitude of a membrane displacement as a function of time, according to a first example; Fig. Figure 6 shows a burst signal and an attenuation signal, which is shown in Fig. 5 shows the membrane deflection; Fig. Figure 7 illustrates an envelope function derived from the one in Fig. The membrane deflection shown in section 5 is generated; Fig. Figure 8 shows a raw signal of an electronic signal corresponding to the amplitude of a membrane deflection as a function of time, according to a second example; Fig. Figure 9 illustrates an envelope function derived from the one in Fig. The membrane deflection shown in section 8 is generated; Fig. Figure 10 shows a raw signal of an electronic signal corresponding to the amplitude of a membrane deflection as a function of time, according to a third example; Fig. Figure 11 illustrates an envelope function derived from the one in Fig. The membrane deflection shown in 10 is generated; Fig. Figure 12 illustrates a closed-loop control algorithm that can be implemented on a control unit 1 described herein.

[0104] The ultrasound transducer 100 according to the in Fig. The embodiment shown in Figure 1 comprises a housing 103. A membrane 104 is arranged on a bottom surface of the housing. The transducer 100 further comprises a piezoelectric element 102, which is configured to convert at least one electrical signal into a mechanical movement in order to excite the membrane 104.

[0105] The transducer 100 further comprises a control unit 1 that provides a burst signal 11 to excite a vibration or periodic membrane displacement 4 in the membrane 104. As a result, the transducer 100 emits an ultrasonic signal 105.

[0106] The transducer 100 is, for example, designed to measure the distance to an object. The ultrasound signal 105 is reflected by the object. The reflected ultrasound signal can be detected by the transducer 100 because it causes the membrane 104 to vibrate. This periodic membrane displacement 4, caused by the reflected ultrasound signal, can be converted into an electrical signal by the piezoelectric element 102. By measuring the time between the emission of the ultrasound signal 105 and the reception of the reflected ultrasound signal, the distance to the object can be measured, assuming a constant and known speed of sound.

[0107] To achieve precise distance measurement results, the membrane 104 must be sensitive to the reflected ultrasound signal; that is, the membrane 104 preferably remains essentially stationary. However, after excitation by the burst signal 11, the membrane 104 continues to oscillate. This movement of the membrane 104 after excitation is also referred to as after-oscillation. Particularly when measuring distances to nearby objects, for example, at distances of less than 10 cm or closer, the after-oscillation must be dampened, as it would otherwise interfere with the reflected ultrasound signal, making precise distance measurement difficult.

[0108] To achieve efficient damping of the reverberation, the control unit 1 is configured to generate a damping signal 12 based on the reverberation behavior of the diaphragm 104 and to apply the damping signal 12 to the diaphragm 104. Preferably, the damping signal 12 excites a damping mode 44 in the diaphragm 104, which has a higher energy dissipation than the transmit mode 43, which is excited by the burst signal 11 to generate the ultrasonic signal 105. More preferably, the housing 103 is designed such that both the transmit mode 43 and the damping mode 44 are stable, thus enabling both efficient generation of the ultrasonic signal 105 and efficient damping.

[0109] The control unit 1 according to a first embodiment, as it is described in Fig. Figure 2 includes an excitation element 2, which is configured to apply the burst signal 11 to the converter 100. The excitation element 2 is further configured to apply the attenuation signal 12 to the converter 100.

[0110] The attenuation signal 12 preferably comprises a plurality of pulses, each having a width 16 (see Fig. 3). In Fig. Figure 3 shows in particular electronic membrane deflection signals corresponding to the membrane deflection 4, 43, 44 and the damping signal 12.

[0111] The control unit 1 is configured to apply the damping signal 12 in three states: a positive state 13, a negative state 15, and a neutral state 14. A pulse is defined, for example, by the fact that the damping signal 12 is in a positive state 13 or a negative state 15 for a certain time, resulting in the corresponding width 16.

[0112] The pulses of the damping signal 12 are centered around peak points 41 of the periodic diaphragm displacement 4 during the after-ringing of the transmit mode 43. At the peak points 41, the diaphragm 104 has a relatively low velocity, which makes the influencing of the diaphragm displacement 4 particularly effective.

[0113] At the peak points 41, the attenuation signal 12 has an amplitude opposite to the diaphragm deflection 4 in the transmit mode 43. That is, if a particular peak point 41 is a local maximum, the attenuation signal 12 is in the negative state 15, and if another particular peak point 41 is a local minimum, the attenuation signal 12 is in the positive state 13. Between the positive state 13 and the negative state 15, the attenuation signal 12 is in the neutral state 14, in which the amplitude of the attenuation signal 12 is essentially zero.

[0114] The width 16 of the pulses of the damping signal 12 is less than half a period 45 of the periodic membrane displacement 4 during the after-ringing. The period 45 is a time interval that lies, for example, between two peak points 41.

[0115] The damping signal 12 changes the mode of the membrane deflection 4, as shown in Fig. Figure 3 illustrates this. This means that at the peak points 41, energy is transferred from the transmit mode 43 to the damping mode 44. During the after-ringing phase, the diaphragm 4 vibrates in the transmit mode 43 if no damping is applied. By applying the damping signal 12, the energy of the diaphragm displacement 4 can therefore be transferred to the damping mode 44 with increased energy dissipation. The application of the damping signal 12 thus enables efficient energy dissipation.

[0116] As in Fig. As shown in Figure 2, the excitation element 2 includes a first intermediate storage unit 21 in which raw data for the damping signal 12 are stored. For example, the first intermediate storage unit 21 stores the peak positions 41 of the diaphragm displacement 4 or the diaphragm displacement signal, the pulse width 16, and the state 13, 14, 15 of the damping signal 12 at each peak position 41. The damping signal 12 can be constructed from this information.

[0117] In particular, the peak positions 41 are timestamps and the widths 16 are measured in arbitrary time units. To assign timestamps to the peak positions 41 and to generate the attenuation signal 12 as a temporal sequence of pulses, the control unit 1 includes a clock generator 5. The clock generator 5 provides a clock signal that serves as the time resolution of the control unit 1.

[0118] Preferably, the time resolution is at least ten times higher than the frequency of the ultrasound signal 105. For example, the ultrasound signal 105 has a frequency between 50 kHz and 100 kHz, for example 80 kHz. In this case, the time resolution of the clock generator is, for example, 1 ms. -1 .

[0119] The excitation element 2 comprises a signal generator 22, which is configured to generate the damping signal 12 from the raw data stored in the first buffer 21 and the clock signal provided by the clock 5. The signal generator 22 generates, for example, a sequence of integers, where each integer represents one of the states 13, 14, 15 of the damping signal 12 at each time according to the clock signal.

[0120] The signal generator 22 is connected to a driver 6, which can be part of the excitation element 2 and / or the control unit 1. It is also possible that the driver 6 is a separate element.

[0121] The driver 6 includes, in particular, a plurality of switches with which the sequence of numbers provided by the signal generator, i.e., the damping signal 12, is converted into an electrical or electronic signal that is applied to the piezoelectric element 102. For example, each state 13, 14, 15 of the damping signal 12 is assigned a voltage of the electrical signal.

[0122] Similar to the damping signal 12, the burst signal 11 can be generated from the raw data stored in the first buffer 21 by the signal generator 22 and the clock 5. The burst signal 11 can also be converted into an electrical or electronic signal by the driver 6 and then applied to the piezoelectric element 102.

[0123] To generate the damping signal 12 from the diaphragm deflection 4, i.e., the diaphragm deflection signal, during the reverberation, the control unit 1 further comprises a feedback element 3. The feedback element 3 is specifically designed to determine the peak locations 41, so that pulses of the damping signal 12 can be assigned to the peak locations 41.

[0124] The peak points 41 are determined by means of a comparator 31. The comparator 31 can be part of the feedback element 3 and / or the control unit 1, or it can be a separate component. The comparator 31 is configured to compare an electrical signal provided by the piezoelectric element 102, corresponding to a membrane displacement 4, with a zero value. At these times, the periodic membrane displacement 4 includes a zero crossing point 42.

[0125] Each peak location 41 can be calculated from the adjacent zero crossings 42 by taking the average of these zero crossings 42. For example, a period between two zero crossings 42, corresponding to the period 45 of the periodic membrane displacement 4, is 10 arbitrary time units. In this example, a first zero crossing 42 can occur at a time interval of 10 arbitrary time units, and a second zero crossing 42 can occur at 20 arbitrary time units. Thus, the corresponding peak location 41 is at 15 arbitrary time units.

[0126] The feedback element 3 further comprises an edge detection unit 32, which is configured to determine at each zero crossing point 42 whether an edge of the membrane displacement 4 or of the membrane displacement signal is rising or falling. From this information, it can be determined whether the preceding and the following peak point 41 correspond to a minimum or a maximum of the membrane displacement 4.

[0127] For example, if the membrane displacement or the membrane displacement signal 4 is decreasing at a specific zero crossing 42, i.e., exhibits a negative gradient, then the preceding peak 41 corresponds to a local maximum and the subsequent peak 41 to a local minimum. If, at another specific zero crossing 42, the membrane displacement 4 or the membrane displacement signal is increasing, i.e., exhibits a positive gradient, then the preceding peak 41 corresponds to a local minimum and the subsequent peak 41 to a local maximum. From this information, the state 13, 15 of the damping signal 12 at each peak 41 can be determined as described above.

[0128] The feedback element 3 further comprises a processing unit 34 and a second buffer 33, which can also be a single element. The processing unit 34 is configured to calculate the raw data for the attenuation signal 12 from the information provided by the comparator 31 and the edge detection unit 32. The second buffer 33 is configured to store the information provided by the comparator 31 and the edge detection unit 32 and make it available to the processing unit 34. The second buffer 33 can also be configured to store the raw data of the attenuation signal 12. The first and second buffers 21, 33 can be interconnected or even constitute a single storage element.

[0129] The control unit 1 is preferably part of an electronic component 200. The electronic component 200 is, for example, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a computer with suitable hardware for signal generation and acquisition. The control unit 1 includes, for example, the excitation element 2, the feedback element 3, and the clock generator 5. The driver 6 and the comparator 31 can be separate elements of the electronic component. It is also possible that the driver 6 and / or the comparator 31 are part of the control unit 1.

[0130] The electronic component further comprises an analog-to-digital converter (ADC) 7 and at least one filter unit 8. The ADC 7 and the filter unit 8 digitize the electrical signal supplied by the piezoelectric element 102, which corresponds to the membrane deflection 4, and process it for evaluation, for example, to perform a distance measurement. This evaluation can be carried out by a digital signal processor 101, which can be part of the electronic component or a separate, additional electronic component.

[0131] The control unit 1 according to the in Fig. The second embodiment shown in Figure 4 essentially comprises the same features as the control unit 1 according to the first embodiment and is additionally configured to adjust the damping signal 12 if, for example, the environmental conditions of the transducer 100 change. For instance, the temperature and / or ambient pressure of the transducer's environment may change. This can occur, for example, when the transducer is used in a car.

[0132] Such a change in environmental conditions can alter the resonant frequency of the transducer's diaphragm 104, which can change the transmit mode 43 and the diaphragm displacement 4 during reverberation. As a result, the damping signal 12 may not provide sufficiently efficient damping to enable precise measurements of small distances. Therefore, an adjustment of the damping signal 12 is desirable.

[0133] The electronic component or control unit 1 further comprises a threshold unit 35, which is configured to detect whether a vibration characteristic of the membrane deflection 4 exceeds a predefined threshold value. If the threshold value is exceeded, the threshold unit 35 triggers an adjustment of the damping signal 12. The adjustment of the damping signal 12 is carried out, for example, by generating a new damping signal 12 by means of the feedback element 3, as described in connection with the first embodiment.

[0134] The vibration characteristic 40 is preferably an envelope function that corresponds to the amplitude of the membrane displacement 4 during the after-vibration. The envelope function is preferably generated by the ADC 7 and the filter unit 8.

[0135] In the Fig. Figures 5 to 11 illustrate the effect of adjusting the attenuation signal.

[0136] Fig. Figure 5 shows the amplitude of the membrane displacement 4 during operation as raw data of a membrane displacement signal corresponding to the membrane displacement 4. The membrane displacement signal is, for example, acquired and provided by the piezoelectric element 102 as a result of the membrane displacement 4.

[0137] During an excitation period of 51 of operation, the burst signal 11 is applied (see below). Fig. 5 and Fig. 6). The burst signal 11 comprises a sequence of alternating rectangular pulses to excite the transmit mode 43 and to generate the ultrasound signal 105.

[0138] Following the excitation period 51, the diaphragm deflection 4 is damped during a damping period 52 using the damping signal 12. At a stop point 54 at the end of the damping period 52, the damping signal 12 is terminated to prevent re-excitation of the diaphragm 104 in the opposite direction. After the damping period 52 has ended, the diaphragm 104 may still exhibit residual vibrations during a reverberation period 53, in which no signal is applied to the piezoelectric element 102.

[0139] The attenuation signal 12 comprises a first part 121 and a second part 122. In the first part 121, the attenuation signal comprises 12 pulses of a first kind 123, and in the second part 122, the attenuation signal comprises 12 pulses of a second kind 124.

[0140] The pulses of the first kind 123 are counter-pulses to the pulses of the burst signal 11, that is, the first part 121 corresponds to a burst signal 11 that is phase-shifted by 180°.

[0141] The pulses of the second type 124 vary in their width. In particular, the second part 122 is generated by the feedback element 3, as described above.

[0142] The first part 121 can reduce the initial energy of the resonating membrane 104, making the membrane 104 more sensitive to damping by the second part 122.

[0143] Fig. Figure 7 shows the vibration characteristic 40 as an envelope function, which is determined from the diaphragm displacement 4. Curve 46 corresponds to a free envelope function, which results when no object is located within a measurement area. Curve 47 corresponds to an object envelope function, which results when an object, the distance to which is to be measured, is located in front of the transducer 100. From the difference between curves 46 and 47, the digital signal processor can calculate the distance to the object.

[0144] As in Fig. As can be seen in Figure 7, the damping by the damping signal 12 is efficient, since curve 47 can be clearly distinguished from curve 46.

[0145] In the Fig. 8 and Fig. For example, in case 9 the environmental conditions of converter 100 have changed so much that the damping is insufficient. A comparison of the Fig. 8 and Fig. Figure 6 shows that the amplitude of the membrane deflection 4 is greater during the decay period 53. A comparison of the Fig. 7 and Fig. Figure 9 shows that the distance to the object cannot be measured because curves 46 and 47 are not clearly distinguishable.

[0146] Small distances cannot be measured accurately because the reflected ultrasound signal must be detected during the decay period 53. The threshold unit 35 therefore monitors the vibration characteristics, preferably within a monitoring range that corresponds to the decay period.

[0147] In the Fig. 10 and Fig. 11. The attenuation signal 12 is adapted to the new environmental conditions. A comparison of the Fig. 10 and Fig. Figure 8 shows that during the decay period 53, the amplitude of the membrane deflection 4 is again reduced. A comparison of the Fig. 11 and Fig. Figure 9 shows that the distance to the object cannot be measured precisely because curves 46 and 47 are not clearly distinguishable. Therefore, an accurate measurement of the distance to the object is possible again.

[0148] Fig. Figure 12 illustrates a closed-loop control algorithm for operating a control unit 1 described here. In step 301, raw data of the burst signal 11 and the damping signal 12 are provided, for example by the first intermediate storage 21.

[0149] In step 302, the burst signal 11 and the attenuation signal 12 are generated by the signal generator 22.

[0150] Steps 301 and 302 provide the burst signal 11 and the attenuation signal 12. The burst signal 11 and the attenuation signal 12 are applied to a piezoelectric element 102 or a membrane 104 of a transducer 100.

[0151] In a further step 303, the vibration characteristic 40 is determined from the membrane deflection signal. In a further step 304, it is determined whether a change in the vibration characteristic 40 exceeds the specified threshold.

[0152] If the threshold is exceeded, a modified damping signal 12 is generated from the membrane deflection signal in step 305 by determining peak points 41 of the membrane deflection signal. This data can be provided in a subsequent execution of step 301.

[0153] If the threshold is not exceeded, step 301 can be executed without adjusting the attenuation signal 12. Therefore, step 301 can follow step 304.

[0154] The invention is not limited to the exemplary embodiments described by reference to them. Rather, the invention encompasses every new feature and every combination of features, including in particular every combination of features in the claims and every combination of features in the exemplary embodiments, even if that feature or combination itself is not explicitly stated in the claims or exemplary embodiments. References 1 control unit 2 Stimulating element 3 Feedback element 4 Membrane deflection 5 Clock generators 6 drivers 7 Analog-to-Digital Converters 8 filter units 11 Burst signal 12 Attenuation signal 13 positive condition 14 Neutral state 15 negative condition 16 Pulse width 21 first buffer 22 Signal generator 31 Comparator 32 Flank detection units 33 second buffer 34 computing units 35 Threshold unit 40 Vibration characteristics 41 Peak point 42 Zero crossing point 43 transmit mode 44 Damping mode 45 Period of periodic membrane displacement 46 free envelope function 47 Object Envelope Function 50 Time 51 Excitation duration 52 Damping duration 53 Reverberation time Stop 54 100 ultrasound transducers 101 Signal processor 102 piezoelectric element 103 cases 104 Membran 105 Ultrasound signal 121 first part of the attenuation signal 122 second part of the attenuation signal 123 Pulse of the first kind 124 Pulse type II 200 electronic components 301...305 Procedure steps 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 4 580 251

[0003] US 6 731 596 B2

[0003] GB 2 593 477 A

[0003] JP 2022 - 73 087 A

[0004] DE 10 2010 039 017 A1

[0004] Cited non-patent literature

[0000] Reducing ring-down time of pMUTs with phase shift of driving waveform. In: Sensors and Actuators A: Physical, Vol.281,2018,S.100-107. ISSN0924-4247(P);1873-3069(E).DOI:10.1016 / j.sna.2 018.08.039

[0003]

Claims

[1] Control unit (1) for an ultrasonic transducer (100), comprising: - a stimulus element (2) which is configured to, to apply a burst signal (11) to the transducer (100) in order to generate and transmit an ultrasonic signal (105), and to apply a damping signal (12) to the transducer (100) in order to dampen a periodic membrane deflection (4) after sending the ultrasound signal (105), - a feedback element (3) that is set up to, to generate the damping signal (12) by determining peak points (41) of a membrane displacement (4) after the membrane excitation has ceased, and to generate the damping signal (12) as a sequence of pulses such that each pulse is centered around a peak point (41), wherein the feedback element (3) is configured to adaptively adjust the widths of the pulses of the damping signal (12) based on a factor of the absolute maximum or minimum values ​​of the membrane deflection (4). [2] Control unit (1) according to claim 1, wherein the feedback element (3) is further configured to monitor at least one vibration characteristic (40) of a diaphragm (104) of the transducer (100) during operation and to generate an adapted damping signal (12) when the vibration characteristic (40) changes above a predetermined threshold. [3] Control unit (1) according to claim 2, wherein the adapted damping signal (12) is generated between the application of two successive burst signals (11). [4] Control unit (1) according to one of the preceding claims, wherein the excitation element (2) is configured to provide the burst signal (11) and the attenuation signal (12) in a common pulse sequence. [5] Control unit (1) according to one of the preceding claims, wherein the excitation element (2) is configured to provide at least the damping signal (12) in at least one positive state (13), at least one negative state (15) and at least one neutral state (14), wherein the excitation element (2) is configured to apply a pulse of the damping signal (12) in the positive state (13) when the corresponding peak point (41) of the diaphragm displacement (4) is a local minimum, to apply a pulse of the damping signal (12) in the negative state (15) when the corresponding peak point (41) of the diaphragm displacement (4) is a local maximum, and to apply the damping signal (12) in the neutral state (14) when the diaphragm displacement (4) includes a zero crossing. [6] Control unit (1) according to one of the preceding claims, further comprising a clock generator (5) configured to provide a clock signal, wherein the peak positions (41) are determined by means of the clock signal. [7] Control unit (1) according to claim 6, wherein a time resolution of the clock generator (5) is at least ten times higher than an operating frequency of the ultrasonic transducer (100). [8] Control unit (1) according to one of the preceding claims, wherein the excitation element (2) comprises a first intermediate storage unit (21) which is configured to store raw data of the burst signal (11) and the attenuation signal (12). [9] Control unit (1) according to claim 8 and claim 6 or 7, wherein the excitation element (2) further comprises a signal generator (22) which is configured to generate the burst signal (11) and the attenuation signal (12) as a temporal pulse sequence using the raw data of the burst signal and the attenuation signal and the clock signal. [10] Control unit (1) according to one of the preceding claims, wherein the feedback element (3) is configured to determine peak points (41) of the membrane deflection (4) by detecting zero crossing points (42) of the membrane deflection (4) and calculating an average value between two adjacent zero crossing points (42). [11] Control unit (1) according to claim 6 and claim 10, wherein the zero crossing points (42) are determined by means of a comparator (31) and the clock signal. [12] Control unit (1) according to one of the preceding claims, wherein the feedback element (3) is configured to generate the damping signal (12) such that it comprises pulses with a width that is less than half a period of the periodic membrane deflection (4). [13] Control unit (1) according to one of the preceding claims in conjunction with claim 5, wherein the feedback element (3) comprises an edge detection unit (32) configured to determine an edge orientation of the periodic membrane deflection (4) at a zero crossing point (42), and wherein a state (13, 14, 15) of the attenuation signal (12) is adapted depending on the edge orientation. [14] Control unit (1) according to claim 13, wherein the feedback element (3) comprises - a second intermediate memory (33) configured to store peak locations (41) and edge orientation, and - a computing unit (34) which is set up to determine the attenuation signal (12) on the basis of data stored in the second intermediate storage (33). [15] Control unit (1) according to one of the preceding claims, wherein the damping signal (12) comprises a first part (121) and a second part (122), wherein in the first part (121) the damping signal comprises pulses of a first kind (123) and in the second part (122) the damping signal comprises pulses of a second kind (124), where pulses of the second kind (124) have a smaller width than pulses of the first kind (123), and the second part (122) is created following the first part (121). [16] Control unit (1) according to claim 15, wherein the feedback element (3) is configured to adapt the second part (122) of the damping signal (12), and the first part (121) is a fixed part which remains unadapted by the feedback element (3). [17] Control unit (1) according to claim 16, wherein the feedback element (3) is configured to adaptively adjust a width of the second type pulses (123) on the basis of a factor of the absolute maximum or minimum value of the membrane deflection (4). [18] Control unit (1) according to one of the preceding claims, wherein the control unit (1) is configured to excite an attenuation mode (44) by applying the attenuation signal (12), which has a higher energy dissipation than a transmit mode (43) which is excited by applying the burst signal (11). [19] Method for operating an ultrasonic transducer (100) comprising a control unit (1) according to any of the preceding claims, comprising the steps - Excitation of a membrane (104) of the transducer (100) to generate and emit an ultrasound signal (105) by applying a burst signal (11) to the membrane (104), - Damping of the membrane (104) after sending the ultrasound signal (105) by applying a damping signal (12), wherein the damping signal (12) is generated by determining peak locations (41) of a membrane displacement (4) after termination of the excitation of the membrane, wherein the damping signal (12) comprises a temporal sequence of pulses, each pulse being centered around a peak location (41). [20] The method of claim 19, further comprising the following steps - Monitoring a vibration characteristic (40) of the membrane, and - Adjusting the damping signal (12) when the vibration characteristic (40) changes above a predetermined threshold. [21] Method according to claim 19 or 20, wherein peak points (41) of the membrane deflection (4) are determined by detecting zero crossing points (42) of the membrane deflection (4) and calculating an average value between two adjacent zero crossing points (42). [22] Ultrasonic transducer (100) comprising a control unit (1) according to any one of claims 1 to 18. [23] Method for using an ultrasonic transducer (100) according to claim 22 for a distance measurement in which a distance between the transducer (100) and an object is determined, wherein the distance is between 3 cm and 2 m inclusive. [24] Electronic component (200) comprising at least one control unit (1) according to any one of claims 1 to 18. [25] Electronic component (200) according to claim 24, comprising a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or a computer with means for signal generation and acquisition. [26] Computer-implemented method for operating a control unit (1) according to any one of claims 1 to 18, comprising the following steps: Providing a burst signal (11) and an attenuation signal (12) by - Reading raw data of the burst signal (11) and the attenuation signal (12) from a first intermediate storage (21), and - Generating the burst signal (11) and the damping signal (12) by the signal generator (22); generating the raw data of the damping signal (12) by determining peak locations (41) of a membrane deflection signal. [27] Data processing device comprising means for carrying out the computer-implemented method according to claim 26. [28] Computer program comprising instructions which, when the program is executed by a computer, cause the computer to execute the computer-implemented method according to claim 26. [29] Computer-readable storage medium on which the computer program according to claim 28 is stored.

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