headphone

Abstract

We provide headphones that accurately determine the wearer's characteristics in a way that is both high-quality and gentle on the ears. [Solution] A headphone 1 is positioned in the ear 6 of the wearer 5 and inserted at least partially into the ear canal 7, comprising a MEMS acoustic transducer 2 that generates and detects ultrasound 3, and a control unit 4 that analyzes ultrasound 9 reflected by tissue structure to determine the wearer 5's physical function, particularly cardiac function and / or respiratory function.

Description

Technical Field

[0001] The present invention relates to a headset, particularly an on-ear headset, an over-ear headset, and / or an in-ear headset, comprising at least one acoustic transducer for generating and detecting at least ultrasonic waves, and a control unit capable of determining at least one characteristic of a wearer of the headset, particularly a body function, preferably a cardiac function and / or a respiratory function, and / or identifying the identity, and / or performing authentication of the wearer based on the generated and detected ultrasonic waves.

Summary of the Invention

Problems to be Solved by the Invention

[0002] The problem of the present invention is to provide a headset capable of reliably determining the characteristics of a wearer with high measurement quality and / or in an ear-friendly manner.

Means for Solving the Problems

[0003] This problem is solved by a headset, a method, and / or the use of a MEMS acoustic transducer having the features of the independent claims. Advantageous or preferred embodiments are the subject matter of the respective dependent claims.

[0004] A headset is proposed. Herein, the headset can be an on-ear headset, an over-ear headset, and / or an in-ear headset. In that case, the on-ear and over-ear headsets are worn over the ears. The in-ear headset is a headset that is at least partially inserted into the external auditory canal of a user or wearer.

[0005] The headset comprises at least one acoustic transducer for generating and detecting at least ultrasonic waves.

[0006] Furthermore, the headphones include a control unit that, based on generated and detected ultrasound, can determine at least one characteristic of the headphone wearer, particularly physical function, preferably cardiac function and / or respiratory function, and / or identify their identity and / or authenticate the wearer. Thus, the headphones can be used to determine vital functions such as the wearer's pulse rate and / or respiratory rate. Additionally or alternatively, the wearer can be identified by using the headphones. The present invention will be described below primarily based on the measurement of physical functions. Additionally or alternatively, the wearer's identity can also be identified. Additionally or alternatively, the wearer can also be authenticated.

[0007] At least one acoustic transducer is a MEMS acoustic transducer capable of generating at least ultrasound within a broadband spectrum. A MEMS acoustic transducer may be a broadband MEMS acoustic transducer. Additionally or alternatively, a MEMS acoustic transducer may be a broadband MEMS acoustic transducer. Additionally or alternatively, a MEMS acoustic transducer may be a MEMS broadband acoustic transducer. Additionally or alternatively, a MEMS acoustic transducer may be a MEMS broadband ultrasonic transducer. Additionally or alternatively, a MEMS acoustic transducer may be a MEMS broadband ultrasonic speaker. For simplicity, the following description will refer only to MEMS acoustic transducers, even if they are MEMS broadband transducers, MEMS broadband ultrasonic transducers, and / or MEMS broadband ultrasonic speakers, etc.

[0008] Because a broadband spectrum can be generated using a MEMS acoustic transducer, a wide range of ultrasound frequencies or measurement frequencies become available for measuring bodily functions. The MEMS acoustic transducer has the ability to generate various ultrasounds with diverse frequencies across a broadband spectrum, thereby making a wide range of ultrasound measurement frequencies available. When measuring bodily functions, ultrasound is emitted and interacts with tissues, the ear, the auditory canal, etc. The resulting altered ultrasound, i.e., reflected ultrasound, is then detected and evaluated again, from which bodily functions are determined. The MEMS acoustic transducer offers the possibility of measuring bodily functions using a wide range of ultrasound frequencies. The MEMS acoustic transducer can generate high-quality ultrasound across the entire broadband spectrum for measuring bodily functions.

[0009] By using a MEMS acoustic transducer capable of generating ultrasound across a broadband spectrum, i.e., a broadband MEMS acoustic transducer, higher resolution, measurement accuracy and / or quality, and / or reliable physical function measurements can be achieved. The ability to generate ultrasound across a broadband spectrum, i.e., the feasibility of the MEMS acoustic transducer generating ultrasound of various frequencies from a broadband spectrum, allows for individual adjustment of the measured frequency of the emitted ultrasound for each ear canal, ear, or wearer. Because the shape of the ear canal and ear varies from wearer to wearer, it may be preferable to select an ultrasound frequency tailored to a specific ear canal, ear, or wearer for reliable physical function measurements. The ultrasound frequency used to measure physical function also varies depending on how and where the headphones are worn. For example, different frequencies may be preferred for on-ear or over-ear headphones compared to in-ear headphones.

[0010] By utilizing a MEMS acoustic transducer capable of generating ultrasound from a broadband spectrum, reliable physical function measurements can be performed for various wearers with different ear canals and ear structures. The MEMS acoustic transducer can generate ultrasound from a broadband spectrum, or ultrasound across a broadband spectrum, with high quality. The MEMS acoustic transducer can provide numerous frequencies, or even all frequencies, from the broadband spectrum. These frequencies can be used to measure individual physical functions.

[0011] A MEMS speaker is advantageous if it can generate a broadband spectrum that includes both audible wavelength and ultrasonic spectra, as it can produce both audible and ultrasonic sound waves. These sound waves from the broadband spectrum that can be generated by a MEMS acoustic transducer can fall within a frequency range from 3kHz, 4kHz, or 15kHz or higher to 40kHz, 80kHz, or 100kHz or lower. A broadband speaker capable of generating sounds in the audible and ultrasonic ranges has the advantage of covering a wider frequency range. This frequency range is broad, for example, from 3kHz to 100kHz, enabling the generation of audible sound waves, allowing users to listen to music or other audio through headphones. On the other hand, a MEMS acoustic transducer can generate ultrasonic waves from a broadband spectrum up to 100kHz for use in measuring bodily functions. Furthermore, the availability of a wider frequency range increases the amount of information available during measurement. It is possible to generate ultrasonic waves at various measurement frequencies from the broadband spectrum, which can then be used to perform a variety of measurements.

[0012] Furthermore, it is advantageous that the control unit and / or MEMS speaker is designed and / or configured to generate a measurement signal from ultrasound having at least one measurement frequency from a broadband spectrum in order to determine physical function. The measurement signal can then be used to measure physical function. The measurement signal is emitted and interacts with the ear, e.g., tissue and / or the external auditory canal, and returns as reflected ultrasound. Here, the reflected ultrasound is detected. By comparing the emitted measurement signal with the detected reflected ultrasound, physical function can be determined. In this case, the measurement signal may represent one or more measurement frequencies derived from a broadband spectrum that can be generated through the MEMS acoustic transducer.

[0013] It is advantageous for the control unit and / or MEMS speaker to be designed and / or configured such that the ultrasonic measurement signal generated by the MEMS acoustic transducer includes one or more, particularly discrete, measurement frequencies. In this case, the broadband spectrum shows one or more peaks, i.e., measurement frequency peaks, brought about by one or more measurement signals. The measurement signals are characterized by very narrow individual frequencies within the broadband spectrum. When the peaks of the measurement signals are clearly defined, evaluation can be facilitated because the reflected ultrasonic can be easily compared to the measurement signals and measurement frequency peaks. Furthermore, this leads to a high signal-to-noise ratio and improved measurement accuracy because unwanted frequencies that cause noise can be easily suppressed.

[0014] It is even more advantageous if the ultrasonic measurement signal includes a continuous measurement frequency, thereby exhibiting a broad measurement frequency spectrum within a broadband spectrum. A broad measurement frequency spectrum has the advantage of being able to collect more information about the reflected signal, which enables detailed analysis. In addition, a continuous and broad measurement frequency spectrum allows for the measurement of various wearer physical functions across a wide spectrum, without the need to match the measurement frequency to a specific ear shape.

[0015] A discrete measurement frequency, i.e., a measurement signal with at least one measurement frequency peak, may be advantageous in that it allows for the isolation of the target / specific signal range for analysis, thereby improving the identification of signal patterns or changes. A continuous measurement frequency spectrum allows for the acquisition of comprehensive and informative data for more accurate analysis of complex reflections and interactions.

[0016] The advantage of discrete measurement frequencies lies in the fact that sharp peaks within the frequency band facilitate evaluation. The advantage of continuous spectra lies in the fact that they allow for detailed analysis of complex signals by utilizing a wide range of broadband spectra.

[0017] It is advantageous for the control unit and / or MEMS speaker to be designed and / or configured such that the width of at least one measured frequency peak of the measured signal is less than 3 kHz, 2 kHz, or 1 kHz. A narrow measured frequency peak allows for precise frequency selection and facilitates the suppression and / or identification of noise and unwanted signal components. This improves analytical accuracy and the overall signal quality as the relevant frequency band is detected more clearly and restrictively. In this case, the measured signal is very narrowband but originates from a broadband spectrum. The measured signal with the measured frequency peak may be in the range between, for example, 3 kHz and 100 kHz. For example, a MEMS acoustic transducer can generate a measured signal with a measured frequency peak of 30 kHz and a width of 2 kHz.

[0018] The narrow bandwidth of the measurement frequency peak optimizes sensitivity to subtle changes and / or patterns in the target signal and reflected ultrasound. Simultaneously, this focusing reduces the signal processing load, as it eliminates the need to consider unimportant data, thereby reducing the rate of error and improving measurement reliability.

[0019] Furthermore, it is advantageous if the control unit and / or MEMS acoustic transducer is designed and / or configured such that the frequency bandwidth of the measured frequency spectrum of the measured signal is 1 kHz or higher, or 5 kHz or higher, or 10 kHz or higher, or 20 kHz or higher, or 30 kHz or higher, or 40 kHz or higher, or 50 kHz or higher, or 60 kHz or higher, or 70 kHz or higher, or 80 kHz or higher. Additionally or alternatively, the measured frequency spectrum of the measured signal may exhibit a frequency bandwidth of less than 70 kHz, or less than 60 kHz, or less than 50 kHz, or less than 40 kHz, or less than 30 kHz, or less than 20 kHz, or less than 10 kHz. In this case, the upper limit is naturally greater than the lower limit. For example, the measured frequency spectrum of the measured signal may exhibit a frequency bandwidth from 30 kHz to 55 kHz. In this case, the frequency bandwidth is 25 kHz. A wider frequency bandwidth allows more frequencies to be used for measurement, thus enabling the collection or measurement of more information.

[0020] It is advantageous for a MEMS acoustic transducer to be designed and / or configured such that the sound pressure level of the sound waves that can be generated in a broadband spectrum is 50 dB or higher, preferably 55 dB or higher, and particularly preferably 70 dB or higher. Furthermore, these sound pressure levels are gentle on the ear and / or tissue.

[0021] According to an advantageous development of the present invention, the MEMS acoustic transducer is designed and / or configured such that the sound pressure level of the sound waves that can be generated within a broadband spectrum is 90 dB or less, preferably 85 dB or less, and particularly preferably 80 dB or less. Limiting the sound pressure level reduces the burden on hearing and improves ease of use for the wearer, even in the case of continuous monitoring. This is particularly important in long-term use. This sound pressure level does not damage the ear and / or tissue.

[0022] Furthermore, it is advantageous for MEMS acoustic transducers to be designed and / or configured such that the sound waves that can be generated within a broadband spectrum exhibit sound pressure levels with a deviation of ±10 dB, and especially ±5 dB, around the mean value, particularly across the entire broadband spectrum. Smaller deviations in sound pressure levels lead to higher measurement accuracy and improved reliability of physical function monitoring. In particular, the measured frequency spectrum of the measured signal may exhibit this deviation across its entire frequency range.

[0023] Furthermore, it is advantageous for MEMS acoustic transducers to be designed and / or configured such that the sound waves they can generate within a broadband spectrum exhibit a continuous spectrum, particularly across the entire broadband spectrum. This allows the MEMS acoustic transducer to generate audible sound waves, for example, by forming all frequencies within the broadband spectrum from 3 kHz to 100 kHz. On the other hand, all ultrasounds up to 100 kHz, for example, can be used for measuring bodily functions. As a result, multiple frequencies become available for measurement.

[0024] It is advantageous for headphones and / or control units to have a modulator capable of integrating and / or modulating electrical signals corresponding to audible sound waves and electrical signals corresponding to measurement signals in the ultrasonic band. This allows sound waves in both the audible and ultrasonic frequency bands to be generated from the modulated signal via the same MEMS acoustic transducer, enabling efficient output of both types of signals. As a result, audible sound waves and ultrasound can be generated simultaneously and / or together from the MEMS acoustic transducer. This integration reduces system complexity by eliminating the need for separate acoustic transducers for the two frequency bands. At the same time, it minimizes the required space, which is particularly advantageous in compact devices such as headphones. Furthermore, the modulation allows for precise control of the signal components, improving the quality and efficiency of the generated sound waves. This offers broad utility in various applications, such as audio output and vital sign monitoring.

[0025] It is advantageous for the headphones and / or the control unit to include a signal generator that can generate a temporal discrete pulse signal, chirp signal, sweep signal, and / or multi-tone signal for generating ultrasonic waves for the purpose of determining body functions. By using chirp signals and sweep signals, an effective analysis of tissue reflections becomes possible, and the measurement accuracy is improved by covering a wider frequency range. By using these signals, it is possible to generate ultrasonic waves that particularly have a continuous spectrum.

[0026] It is advantageous for the headphones to include an MLS signal generator that can generate an M-sequence signal. Based on this, the MEMS acoustic transducer can generate at least ultrasonic waves within a broadband spectrum. It is advantageous for the signal generator to include an MLS signal generator or to be an MLS signal generator. Therefore, the signal generator can also generate an M-sequence signal in addition to or as an alternative to a temporal discrete pulse signal, chirp signal, sweep signal, and / or multi-tone signal for generating ultrasonic waves.

[0027] When measuring using the headphones or when executing a procedure, a so-called M-sequence signal (MLS signal) can be used. The M-sequence signal is a pseudo-random bit sequence corresponding to a pulse with a uniform distribution of spectral energy density over a wide frequency band and a narrow autocorrelation. As a result, all frequencies within the frequency band are excited simultaneously, enabling a complete determination of the acoustic impulse response of the external auditory canal. The technical advantages lie in the uniform spectral excitation and the ability to determine the transmission characteristics of the ear without the need for prior calibration.

[0028] In this method, ultrasonic waves generated from the M-sequence signal are radiated into the external auditory canal by an acoustic transducer unit such as an MEMS acoustic transducer unit. The echo signal or reflected ultrasonic waves reflected within the ear can be measured by the same or another acoustic transducer unit. By evaluating the ratio of the propagation time and amplitude between the transmission signal and the echo signal, the characteristics of the user can be determined.

[0029] The M series signals are generated in digital form and then filtered. The filtering serves to adapt the frequency band of the signals to each measurement scenario, particularly by removing audible frequencies and shifting the usable range into the ultrasonic band. The resulting signal waveform exhibits a uniform energy distribution over the desired frequencies. As a result, intermodulation distortion is dispersed over a wide band and thus does not pose a problem for measurement purposes.

[0030] After filtering, the signal is converted into an electrical transmission signal by a digital / analog converter and output to the acoustic transducer unit. The acoustic echo signal changed by reflection and absorption in the ear is digitized by an analog / digital converter and sent to the processing unit. The impulse response of the system can be determined by the cross-correlation of the transmission signal and the received signal. This includes all the acoustic characteristics of the external auditory canal and serves as the basis for determining physiological parameters.

[0031] Furthermore, the processing unit and / or the control unit can perform spectral analysis such as Fourier analysis, wavelet analysis, periodogram analysis, etc. to determine the time-varying characteristics of the impulse response and frequency response. Additionally or alternatively, the processing unit and / or the control unit can also perform cepstrum analysis. This enables the detection of even the smallest changes in the acoustic behavior of the ear caused by pulsation, breathing, head movement, etc. By using cepstrum analysis, for example, the characteristics of the wearer can be distinguished with very high precision.

[0032] The processing unit referred to here may be the control unit. Alternatively, the control unit may include the processing unit.

[0033] A special advantage of the present invention is that measurements can be performed without relying on the geometric shape of the ear canal, the precise positioning of the headphones, and pre-calibration to specific measurement frequencies assigned to the wearer. Since the M-sequence signal excites all frequencies within the frequency band simultaneously, anatomical differences are automatically taken into account, thereby eliminating the need for individual calibration.

[0034] By using a single acoustic transducer unit that operates alternately as a speaker and microphone, system miniaturization and high-precision measurements can be achieved. At the same time, by integrating it into commercially available headphones, it can be used discreetly and continuously. Thus, the present invention enables a robust, wideband, and calibration-free measurement method for determining a user's personal or physiological characteristics using acoustic signals in the ultrasonic band.

[0035] It is advantageous to generate M-sequence signals using an MLS signal generator. MLS signal generators typically implement a linear feedback shift register (LFSR) that generates a defined bit sequence with a maximum period length. This allows for accurate reproduction of the signal waveform and creates a precise reference for cross-correlation with echo signals.

[0036] M-sequence signals have a period length of 2 n It is advantageous to generate the signal using a linear feedback shift register with a value of -1. Here, the number of bits n in the shift register is in the range of 8 to 16. A larger value of n results in higher frequency resolution and signal-to-noise ratio.

[0037] It is advantageous for the generated ultrasound to be generated and / or processed at a sampling rate between 50 kHz and 200 kHz, particularly 96 kHz. The sampling rate determines the highest measurable frequency (Nyquist limit) and the temporal resolution of the measurement. At 96 kHz, the ultrasound band up to 48 kHz is covered, allowing for accurate detection of the acoustic properties of the ear beyond the audible range.

[0038] In an advantageous development of the present invention, the M-sequence signal generated through the MLS signal generator is filtered by at least one filter unit. This generates a digital transmission signal that produces ultrasound. Filtering refers to frequency-selective adjustment of the signal to suppress unwanted frequencies. Digital filtering removes audible frequencies and adjusts the spectral shape of the signal to suit the measurement purpose. This generates an acoustic transmission signal that is ultrasound. Since this signal is entirely in the ultrasonic band, the measurement does not interfere with the user's life.

[0039] It is advantageous to have at least one filter unit performing bandwidth limiting. This removes frequencies, particularly in the audible range. This prevents the measurement signal from being acoustically perceived by the user and reduces interference with the reproduced signal.

[0040] Furthermore, it is advantageous to have at least one filter unit perform pre-distortion. Pre-distortion compensates for the frequency-dependent sensitivity of the speaker and microphone. This linearizes the entire transfer function and improves the quality of the reconstructed impulse response.

[0041] The filter unit is preferably designed as a digital filter device that processes data signals generated from M-sequence signals in real time. In this case, the filter unit can be implemented as a software module within a processing unit or control unit, or as an independent hardware component. Signal processing is preferably performed by digital filter structures particularly suitable for embedded systems due to their stability and computational efficiency, especially Butterworth filters and bi-quadratic filters. Here, filter parameters can be dynamically adjusted to suit each measurement scenario, and the usable frequency band, for example, the ultrasonic band between 20 kHz and 75 kHz, can be precisely limited. Digital implementation of the filter unit enables highly reproducible and low-loss signal formation, thereby ensuring that the transmitted signal exhibits a constant spectral energy density over the desired frequency band.

[0042] In a preferred embodiment, the filter unit comprises a combination of high-pass, low-pass, and / or band-pass filters that can be cascaded or connected in parallel. This allows for the deliberate tuning of the M-sequence signal to suppress noisy low-frequency components and unwanted harmonic components. By using a Butterworth filter with the flattest amplitude characteristics in the passband, the impact on the phase position of the M-sequence signal is minimized. This is important for subsequent cross-correlation and impulse response determination. Furthermore, the bi-quadrature filter structure allows for flexible adjustment of the slope and attenuation, so that the filter characteristics can be optimized to match the electroacoustic characteristics of the acoustic transducer unit using it. Thus, the filter unit contributes significantly to the linearity and accuracy of the overall measurement method.

[0043] A MEMS acoustic transducer is advantageous if it comprises at least one piezoelectric element and a diaphragm coupled to at least one piezoelectric element. Here, the at least one piezoelectric element and the diaphragm are coupled to each other via a reinforcing plate, allowing the diaphragm to be displaced planarly to generate ultrasonic waves. The arrangement of the piezoelectric element with the diaphragm enables the efficient generation of high-frequency ultrasonic waves, contributing to improved signal quality and accurate detection. The planar coupling of the diaphragm and at least one piezoelectric element via the reinforcing plate allows for the generation of very stable ultrasonic waves with a continuous spectrum in the frequency band.

[0044] According to an advantageous development of the present invention, the MEMS acoustic transducer is positioned so that when headphones are used for a predetermined purpose, ultrasound is emitted into the wearer's ear canal. Direct emission into the ear canal ensures high signal quality and enables accurate detection of vital parameters by measuring specific reflections within the ear canal.

[0045] It is advantageous to be able to generate and detect ultrasound using the same MEMS acoustic transducer. Additionally or alternatively, the headphones may also be equipped with a microphone and / or another MEMS acoustic transducer, which can detect the ultrasound generated by the MEMS acoustic transducer.

[0046] Furthermore, a method is proposed for determining the physical function, particularly cardiac and / or respiratory function, of a wearer of headphones, especially on-ear headphones, over-ear headphones, and / or in-ear headphones. In this method, the headphones may exhibit at least one of the features described above and / or below. Furthermore, at least one of the features described above and / or below may be used in this method depending on its characteristics and / or application.

[0047] This method uses a MEMS acoustic transducer in headphones, particularly a broadband MEMS acoustic transducer, to generate ultrasound from a broadband spectrum. Ultrasound is used to measure bodily functions. Since ultrasound originates from a broadband spectrum, the MEMS acoustic transducer can generate these ultrasounds from a broadband spectrum. This makes a wide range of ultrasound frequencies available for measuring bodily functions.

[0048] In this method, ultrasound is detected using a MEMS acoustic transducer, particularly a broadband MEMS acoustic transducer, and / or another microphone.

[0049] Furthermore, the headphone's control unit determines the wearer's physical capabilities based on the generated and detected ultrasound waves.

[0050] To determine bodily function, it is advantageous for the MEMS acoustic transducer to emit a measurement signal with one or more measurement frequencies from a broadband spectrum that can be generated. This allows for flexible selection of measurement frequencies within the broadband spectrum, thus meeting specific requirements for the analysis and detection of bodily function. Furthermore, the use of various frequencies to adjust signal quality to various anatomical and physical conditions improves the robustness and versatility of the system.

[0051] It is advantageous if at least one measurement signal is generated, and that the ultrasound exhibits one or more measurement frequency peaks within a broadband spectrum. Generating measurement frequency peaks allows for targeted analysis, thereby minimizing noise and improving signal quality. This can improve the signal-to-noise ratio because a narrowband measurement signal is emitted, making it easier to detect noise and background noise. This helps to reliably and efficiently identify specific patterns or changes in reflected signals. Furthermore, an emitted measurement signal with one or more measurement frequency peaks within a broadband spectrum generates reflected signals that exhibit similarly sharp peaks, which simplifies evaluation.

[0052] Additionally or alternatively, it is advantageous if a single measurement signal is generated and its ultrasound contains a particularly continuous measurement frequency spectrum within a broadband spectrum. A continuous measurement frequency spectrum has the advantage of building a broader database that enables more comprehensive analysis. Multiple measurements can be performed simultaneously by emitting multiple frequencies for measurement at the same time. By utilizing the entire broadband spectrum, complex reflections and interactions of ultrasound with tissues and surfaces can be detected in more detail. This improves the versatility and adaptability of the system to various applications. A broad measurement frequency spectrum within a broadband spectrum automatically includes measurement frequencies that yield optimal measurement results.

[0053] It is advantageous for the control or processing unit to perform Fourier analysis, wavelet analysis, or spectrogram analysis before determining at least one feature. Additionally or alternatively, the processing unit may perform cepstrum analysis to determine at least one feature. Additionally or alternatively, these analyses may be performed individually or in combination for authentication purposes. These analyses are used to convert the echo signal into a frequency band, thereby allowing for the identification of spectral changes. Thus, resonance shifts or attenuation changes containing physiological information are detected.

[0054] It is advantageous for the control unit to execute a search program and / or search algorithm that determines the appropriate measurement frequency for the headphone wearer. Optimal signal quality and measurement accuracy are achieved by adjusting to the wearer's individual circumstances, such as the specific anatomical structure of the ear canal and / or individual tissue characteristics. This function allows for the dynamic and / or automatic adjustment and / or optimization of the measurement frequency of the measurement signal to suit the wearer, improving the reliability of detecting bodily functions such as pulse rate and respiratory rate. Furthermore, it becomes easier to wear as it does not require manual calibration or adjustment. System operation becomes simpler for the user, and consistent performance is guaranteed. For example, the search program and / or search algorithm may be executed so that the control unit tries multiple measurement frequencies and then selects the frequency that yields the best results. For example, the control unit can try all measurement frequencies from 20 kHz to 100 kHz in 1 kHz increments.

[0055] Furthermore, it is advantageous to generate ultrasound in which the width of at least one measured frequency peak in the broadband spectrum of the measured signal is less than 3 kHz, 2 kHz, or 1 kHz. This ensures that the measured signal is sufficiently narrowband but originates from a broadband spectrum that can be generated through a MEMS acoustic transducer. Since reflected ultrasound also exhibits a narrowband spectrum, the sharper the measured signal, the easier the evaluation becomes.

[0056] Additionally or alternatively, ultrasound can be generated with a measurement frequency spectrum bandwidth greater than 5kHz, 10kHz, 20kHz, 30kHz, 40kHz, 50kHz, 60kHz, 70kHz, or 80kHz and / or less than 80kHz, or less than 70kHz, or less than 60kHz, or less than 50kHz, or less than 40kHz, or less than 30kHz, or less than 20kHz, or less than 10kHz, or less than 5kHz. In this case, the upper limit is greater than the lower limit. This allows for the simultaneous emission of multiple frequencies for measurement, or the emission of a wide measurement signal corresponding to a wide measurement frequency spectrum, thus enabling the collection of more information.

[0057] It is advantageous to generate ultrasound with a sound pressure level of 50 dB or higher, preferably 55 dB or higher, and particularly preferably 70 dB or higher. A uniform and sufficiently high sound pressure level ensures robust signal quality, enabling accurate analysis even when the signal-to-noise ratio is low.

[0058] It is advantageous to generate ultrasound with a sound pressure level of 90 dB or less, preferably 85 dB or less, and particularly preferably 80 dB or less. Limiting the sound pressure level minimizes the burden on hearing and makes the device easier to wear, thus supporting continuous monitoring. Using a sound pressure level in the range of approximately 50 dB to 90 dB allows for reliable measurements without damaging the ear and / or tissues.

[0059] It is particularly advantageous if the sound pressure level exhibits a deviation of ±10 dB, especially ±5 dB, around the average value, across the entire frequency range of the measured frequency spectrum. A small deviation in sound pressure level ensures a stable and reliable measurement environment for monitoring vital parameters.

[0060] Furthermore, it is advantageous to generate ultrasound that exhibits a continuous spectrum within the measured frequency spectrum, particularly across its entire frequency bandwidth. A continuous spectrum increases information density and expands the possibilities for evaluation, resulting in more accurate and consistent measurement results. In contrast to discrete spectra, a continuous spectrum makes multiple frequencies available for measurement.

[0061] It is advantageous to generate ultrasound using a signal generator. Using a signal generator allows for precise control and optimization of the ultrasonic signal, improving measurement quality.

[0062] To generate audible sound waves and ultrasound, it is advantageous that the corresponding electrical signals are integrated and / or modulated by a modulator, where this modulated signal is then sent to and converted by a MEMS acoustic transducer. This signal combination allows for the efficient use of the MEMS acoustic transducer, enabling the simultaneous generation of both frequency bands, i.e., audible sound waves and ultrasound.

[0063] It is advantageous for the measurement signal to be emitted at intervals of 30 microseconds to 300 milliseconds, particularly between 1 microsecond and 100 milliseconds. Emitting the measurement signal in this temporal manner allows for flexible adaptation to specific usage requirements. Shorter intervals between signals increase temporal resolution, making it particularly suitable for accurate detection of rapid changes. Simultaneously, longer intervals between measurement signals can reduce power consumption.

[0064] According to an advantageous development of the present invention, ultrasound is generated using chirp signals, sweep signals, and / or multitone signals within the measurement spectrum and / or broadband spectrum. This makes it possible to generate ultrasound in the aforementioned frequency band and / or continuous spectrum.

[0065] Furthermore, it is advantageous for ultrasound to be generated and detected by the same MEMS acoustic transducer to determine bodily functions. This reduces the number of required components and improves system efficiency. This is particularly advantageous in compact, portable devices such as headphones. Additionally or alternatively, the headphones may also include another MEMS acoustic transducer and / or another microphone for detecting reflected ultrasound.

[0066] It is particularly advantageous when audible sound waves and ultrasound are generated by the same MEMS acoustic transducer, where it is preferable that the audible sound waves are generated simultaneously with and / or together with the ultrasound. Generating both sound waves with the same acoustic transducer reduces the need for separate components, enabling a more compact structure. This is particularly advantageous in portable devices such as headphones.

[0067] It is advantageous for the MEMS acoustic transducer to generate audible sound waves, preferably simultaneously with ultrasound. Simultaneous generation of audible sound waves and ultrasound enables the versatile use of the acoustic transducer and enhances the functionality of headphones. This allows, for example, headphones to be used for listening to music while simultaneously measuring bodily functions.

[0068] According to an advantageous development of the present invention, physical function is evaluated by an algorithm and / or evaluation program, where it is preferable that the algorithm and / or evaluation program is executed by a control unit. The use of an algorithm for signal processing enhances the accuracy and efficiency of cardiac and respiratory signal analysis and improves the reliability of the continuous monitoring system.

[0069] The use of particularly broadband MEMS acoustic transducers is proposed for headphones and / or methods for determining physical function. In this case, the headphones and / or methods exhibit at least one of the features described above and / or below. Furthermore, the MEMS acoustic transducer exhibits at least one of the features described above and / or below for use in accordance with the headphones and / or methods described herein.

[0070] One of the characteristics of broadband ultrasonic sensor technology is that systems equipped with broadband MEMS acoustic transducers can generate very short pulses that possess both high information density and high energy density. This is due to the unique properties of broadband signals.

[0071] The Fourier transform exhibits an inverse relationship in pulsed signals. The duration of a pulse, especially a time-discrete pulse, is inversely proportional to its bandwidth. Therefore, broadband MEMS acoustic transducers can generate very short pulses, enabling measurements with high temporal resolution.

[0072] In cardiac and / or respiratory monitoring, the principle of function is based on the following steps: A MEMS acoustic transducer continuously emits short, broadband ultrasonic pulses toward the ear canal. The sound waves interact with the volume of air and tissue within the ear. As blood flows through the blood vessels in the ear, subtle movements (volume changes) and changes in tissue density occur. These changes affect the reflected ultrasound.

[0073] The microphone in the headphones, particularly a MEMS acoustic transducer emitting ultrasound, another microphone, and / or another MEMS acoustic transducer detect the reflected waves and record them at a high sampling rate to detect the details of short pulses. The signal is then processed for extraction. In the process, algorithms can remove interference and other artifacts, and determine abnormalities in cardiac and / or respiratory functions, such as pulse rate, heart rate, or respiratory rate.

[0074] Broadband MEMS acoustic transducers offer significant advantages in measuring bodily functions. By generating extremely short pulses, signals can be detected with high resolution, providing detailed information about reflected signals. This allows for the accurate identification of subtle and rapid changes in tissue and blood flow. Furthermore, because broadband ultrasound penetrates tissue at different depths depending on the frequency, it contributes to the acquisition of richer data and improves the accuracy of pulse rate measurement.

[0075] Using broadband MEMS acoustic transducers enables signal processing techniques such as frequency band analysis and adaptive filtering, further enhancing the ability to extract pulse components from noisy data. Furthermore, the use of broadband signals improves the signal-to-noise ratio because the frequency distribution allows for easier identification of the actual pulse wave signal from background noise. This improves the clarity and reliability of physical function measurements. These techniques allow for the extraction of additional information from the received signal, improving the accuracy and reliability of ToF measurements. Additionally, broadband ultrasound can compensate for and adapt to environmental variations such as temperature and humidity changes, which can affect sound velocity and thus impair the accuracy of propagation time measurements.

[0076] This method is non-invasive and allows for comfortable continuous monitoring by using low sound pressure levels that prevent potential discomfort for the wearer. The high energy density of the pulses allows for limiting sound pressure levels without compromising measurement quality, thus improving ease of use for the user.

[0077] Functionally, it offers high tolerance to slight changes in sensor position, ensuring consistent measurement accuracy even when the equipment is not perfectly aligned. The high information density generated through broadband ultrasound also improves the calibration process, allowing for more precise adjustments to accommodate individual differences in ear canal and tissue characteristics.

[0078] The broadband ultrasonic MEMS acoustic transducer can distinguish between the direct signal path and the reflected signal path based on frequency components, thereby improving its ability to handle multipath effects (the phenomenon of a signal being reflected from multiple surfaces). This improves the accuracy of identifying relative positions in space.

[0079] A shorter pulse duration allows the system to generate sharper and more detailed images. A shorter pulse means a smaller pulse width relative to distance, contributing to improved resolution of fine features and motion.

[0080] Furthermore, broadband ultrasonic signals are less susceptible to interference and noise compared to narrowband signals, improving the clarity of the received signal. This is a crucial advantage in accurately measuring propagation time.

[0081] Broadband MEMS acoustic transducers offer high resolution and accuracy in time-of-flight applications. Improved handling of multipath and reflection effects, enhanced signal quality, refined temporal and spatial resolution, improved material interaction, and the potential for advanced signal processing combine to enhance system capabilities for gesture recognition accuracy, distance measurement, and object characterization in various environments.

[0082] Broadband MEMS acoustic transducers can generate ultrasound across a wide frequency range. This means that the acoustic transducer does not emit a single fixed frequency, but rather emits sound waves across a continuous spectrum (e.g., from at least 20 kHz to 40 kHz, or up to 60 kHz, or 80 kHz, or up to 100 kHz). In this case, the spectrum can be a continuous spectrum, especially in the measurement spectrum. This multi-frequency, or continuous, frequency spectrum improves the resolution of the signal because different frequencies penetrate tissue at different depths and exhibit different reflections on different surfaces. This allows for more precise detection and analysis of details, which is particularly useful in monitoring cardiac and respiratory function.

[0083] Short pulses in the ultrasound bandwidth allow for accurate identification and analysis of rapid bodily changes such as heart rate. A wide range of frequencies increases the amount of information in the reflected signal, improving the accuracy of measurements such as pulse rate and respiratory rate. Furthermore, the signal bandwidth reduces background noise (interference), allowing for easy and reliable detection of the actual signal.

[0084] The broadband MEMS acoustic transducer offers strong resistance to even slight changes in sensor position. Even if headphones or a headset shift slightly within the ear, the acoustic transducer can continue accurate measurements. This is a significant advantage in portable devices, as it eliminates the need for precise positioning of the instrument to obtain accurate results. Furthermore, the diversity of additional data ensures superior calibration and accuracy, as the instrument adjusts to individual differences in the user's ear canal.

[0085] It is also proposed and advantageous to use an M-sequence signal to determine and / or authenticate at least one characteristic of the wearer. Here, the M-sequence signal is preferably designed and / or generated in accordance with the preceding and / or subsequent descriptions. The M-sequence signal is used for the method described above and / or subsequent descriptions. The technical advantage of this use is that the calibration process is unnecessary because the M-sequence signal is available regardless of the anatomical structure or the placement of the device in the ear canal. By utilizing the M-sequence signal, it is possible to generate a transmission sound wave for measurement and determination.

[0086] An M-sequence signal (MLS signal) is a deterministic pseudo-random digital signal defined by a bit sequence generated using a linear feedback shift register (LFSR). This shift register has a maximum period length of 2 n A sequence of -1 is generated, where n is the number of bits in the register. The number of bits is preferably in the range of 8 to 16, which balances signal resolution, period duration, and computational load.

[0087] An M-sequence signal consists of a time-dependent sequence of discrete values ​​that typically take on two states, 0 and 1. For further digital processing, the signal is transformed into a symmetrical form, where the values ​​are centered around the zeros, for example, -1 and +1. This allows for the mathematically stable application of digital filters and linear signal processing in floating-point representations. Each value of the signal is output at a constant time interval determined by the sampling rate. The sampling rate is typically between 50 kHz and 200 kHz, preferably 96 kHz, which provides a usable frequency bandwidth up to 48 kHz.

[0088] A key characteristic of M-sequence signals is their flat frequency spectrum. They exhibit a nearly uniform spectral energy density across the entire frequency band used. As a result, all frequency components are excited simultaneously with equal energy, allowing for the complete and simultaneous detection of the system's transfer function. The autocorrelation function of an M-sequence signal approximates the Dirac impulse function or the Kronecker delta function. The cross-correlation between the transmitted and received signals allows for the accurate reconstruction of the system's impulse response. This characteristic is particularly advantageous in broadband measurement methods, as it allows for the determination of the entire system response in a single measurement cycle.

[0089] To adapt to each measurement scenario, the digital M-sequence signal is filtered. Filtering is preferably performed by a digital filter unit that frequency-selectively adjusts the signal and optimizes it for the measurement range. The filter unit may comprise a combination of cascaded or parallel high-pass, low-pass, and band-pass filters. Preferably, a digital Butterworth filter with a flat amplitude characteristic, or a bi-order filter structure with adjustable slope and attenuation, is used. These filter structures ensure low-loss and phase-stable signal processing.

[0090] Filtering is performed specifically to limit the frequency spectrum of the signal to a desired operating range. This involves removing audible frequencies, thereby shifting the signal to the ultrasonic band. The upper frequency limit is preferably set between 40 kHz and 100 kHz, while the lower frequency limit may be between 20 kHz and 75 kHz. This ensures high spectral resolution and measurement accuracy while preventing the acoustic transmission signal from being heard by the user. The resulting signal waveform is a smoothed, continuous digital transmission signal with a uniform energy distribution across the desired frequency band.

[0091] In addition to bandwidth limiting, the filter unit can pre-distort the signal with frequency dependence to compensate for the nonlinear frequency response and frequency-dependent sensitivity of electroacoustic transducers, particularly speakers and microphones. This achieves linearization of the entire system's transfer function and improves the accuracy of impulse response determination.

[0092] The digital transmission signal generated by the filter unit has a smoothed, nearly sinusoidal structure and can be converted to an analog electrical transmission signal via a digital-to-analog converter. The signal is then radiated as an acoustic signal from an acoustic converter unit, such as a MEMS acoustic converter unit. The filtered M-sequence signal maintains its deterministic and periodic characteristics even after smoothing, and is therefore still clearly identifiable in cross-correlation analysis.

[0093] The main technical advantages of M-sequence signals are their broad bandwidth, the fact that they require no calibration, and their robust excitation signal. Because all frequencies are excited simultaneously and uniformly, there is no need for individual calibration to suit the user or the shape of the ear canal. Only the shape of the measured impulse response is affected by anatomical differences or changes in instrument position; the method itself is not compromised.

[0094] Furthermore, M-sequence signals distribute unavoidable intermodulation distortion across a broad spectrum. Since these distortion components are below the audible range, they do not pose a problem in measurement techniques. This achieves high interference immunity, allowing the signal to be accurately evaluated even in nonlinear system operation.

[0095] Furthermore, the mathematical structure of the signal enables efficient implementation. M-sequences can be generated with minimal computational load in software or hardware, making them suitable for resource-constrained embedded systems. The repetition of the signal at each period length allows for continuous time-series measurements, enabling real-time detection of changes in impulse and frequency responses.

[0096] Therefore, M-sequence signals are suitable excitation signals for broadband measurement methods, particularly for determining transfer functions, impulse responses, and physiological or biometric features. They combine high spectral coverage, reproducibility, robustness, and no calibration required, all within a single deterministic signaling principle.

[0097] Further advantages of the present invention are described in the following embodiments. Figures are shown below. [Brief explanation of the drawing]

[0098] [Figure 1] This is a schematic cross-sectional view of an in-ear headphone equipped with a MEMS acoustic transducer. [Figure 2] This is a schematic cross-sectional view of headphones in the form of over-ear or on-ear headphones equipped with a MEMS acoustic transducer. [Figure 3] This is an exemplary broadband spectral diagram of a broadband MEMS acoustic transducer in the ultrasonic band. [Figure 4] This is an illustrative diagram showing a measurement signal emitted from a broadband MEMS acoustic transducer to measure bodily function, where the measurement signal is a frequency peak. [Figure 5]This is an exemplary diagram representing a measurement signal emitted from a broadband MEMS acoustic transducer to measure bodily function, where the measurement signal is a broadband spectrum. [Figure 6] This is a schematic cross-sectional view of a MEMS acoustic transducer equipped with a piezoelectric element coupled to a diaphragm. [Figure 7] This is a schematic cross-sectional view of a MEMS acoustic transducer, which includes two piezoelectric elements coupled to a diaphragm. [Modes for carrying out the invention]

[0099] The embodiment shown in Figure 1 illustrates headphones 1 in the form of in-ear headphones positioned in the ears 6 of a wearer 5. Headphones 1 are inserted at least partially into the ear canal 7. Headphones 1 include an acoustic transducer 2, which is a MEMS acoustic transducer 2 used to generate and detect ultrasound 3. The acoustic transducer 2 is positioned so that the generated ultrasound 3 is radiated into the ear canal 7 of the ear 6.

[0100] As can be seen from the embodiment in Figure 1, the headphones 1 are equipped with a control unit 4 that processes detected ultrasound 3 in order to determine the physical functions of the wearer 5. These physical functions include, for example, cardiac function and respiratory function. These functions can be detected by analyzing the ultrasound 9 reflected by tissue structure.

[0101] Furthermore, the headphones 1 are equipped with a signal generator 19 that can generate various signal waveforms, such as chirp signals, sweep signals, and multitone signals, which are used to form ultrasonic waves 3. By utilizing these signal waveforms, ultrasonic waves 3 having a continuous spectrum can be generated, for example.

[0102] As shown in Figure 1, the acoustic transducer 2 is designed to generate sound waves 3 from a broadband spectrum 10. The broadband spectrum 10 can extend, for example, to a frequency band from 3 kHz to 80 kHz. This wide frequency coverage has the advantage that a variety of frequencies can be used for measurement. By using the broadband spectrum 10, the signal-to-noise ratio can be improved.

[0103] Additionally or alternatively, headphones 1 can generate ultrasound 3 having a sound pressure level 12 within a broadband spectrum 10, preferably between 50 dB and 80 dB. This limitation of sound pressure level 12 contributes to measurement stability and ensures comfortable use by minimizing strain on hearing.

[0104] Furthermore, the headphones 1 shown here are equipped with a modulator 20. By utilizing the modulator 20, it is possible to simultaneously generate sound waves 3 within the audible frequency spectrum, i.e., audible sound waves 3, and sound waves 3 within the ultrasonic spectrum, i.e., ultrasonic waves 3. In this process, the modulator 20 can integrate or modulate the corresponding electrical signals, so that the MEMS acoustic transducer 2 generates audible sound waves and ultrasonic waves 3 from them. This makes it possible to listen to music and measure bodily functions simultaneously.

[0105] The embodiment shown in Figure 2 illustrates headphones 1 designed as either over-ear or on-ear headphones. Headphones 1 include a MEMS acoustic transducer 2 designed to generate and detect ultrasound 3. These ultrasounds 3 are emitted into the ear canal 7 of the wearer's ear 6, thereby enabling the detection of reflections of these waves in tissue structures. The reflected ultrasound 9 is detected through the acoustic transducer 2 and subjected to further analysis.

[0106] As is clearly visible in Figure 2, the control unit 4 is integrated into the headphones 1. This control unit 4 is used to evaluate the ultrasound 9 reflected by the eardrum 8 and / or surrounding tissue structures. This makes it possible to monitor the wearer's physical function, particularly cardiac and respiratory function. Using ultrasound 3 to determine these vital parameters allows for the accurate detection of subtle changes in tissue and blood flow. This supports a detailed analysis of cardiac and respiratory signals.

[0107] The headphones 1 also include a signal generator 19 capable of generating various types of signals, such as chirp and sweep signals. These signals can be used to generate a measurement signal 21 via ultrasound 3. Additionally, the measurement spectrum may exhibit a sound pressure level 12 with a deviation of ±10 dB, particularly ±5 dB. This improves the accuracy of identifying changes in blood flow and tissue movement. This is particularly advantageous in reliable monitoring of cardiac and respiratory function.

[0108] Furthermore, the MEMS acoustic transducer 2 is designed to generate ultrasound 3 in a broadband spectrum 10. Such a broadband spectrum 10 enhances flexibility in signal processing and enables the detailed detection of various tissue structures using a variety of measurement frequencies. This improves the ability to detect minute movements and ensures high measurement accuracy.

[0109] Additionally or alternatively, headphones 1 are designed such that the sound pressure level 12 of the generated ultrasound is preferably between 50 dB and 80 dB. This limitation of sound pressure level 12 contributes to measurement stability and minimizes hearing strain. This improves ease of use for the wearer 5 and allows for extended use of headphones 1.

[0110] The embodiment shown in Figure 2 therefore illustrates headphones 1 equipped with ultrasonic technology and a control unit 4 for accurately detecting the vital functions of the wearer 5. The combination of broadband ultrasound and optimized sound pressure levels 12 provides a reliable solution for continuously monitoring the physical functions of the wearer 5.

[0111] Figure 3 shows an example of a broadband spectrum 10 that can be generated through the MEMS acoustic transducer 2. The horizontal axis represents frequency 11 in Hertz (Hz), and the vertical axis represents sound pressure level 12 in decibels (dBSPL, which means "sound pressure level" expressed in dB). The broadband spectrum 10 shown in this example covers a range of approximately 20 kHz to 80 kHz. By using the MEMS acoustic transducer 2, it is also possible to generate particularly low frequencies 11. This allows the broadband spectrum 10 to reach 3 kHz, and not only ultrasound 3 but also audible sound waves 3 can be generated.

[0112] In particular, the broad frequency band coverage in the range of 3kHz to 80kHz offers advantages when detecting different types of tissue and can improve the resolution of measurement data.

[0113] Such a broadband spectrum 10 improves the adaptability of physical function measurements to various wearers 5 of the headphones 1. Various wearers 5 of the headphones 1 also have different ear canal shapes 7. These different ear canal shapes can be accommodated by selecting different measurement frequencies from the broadband spectrum 10 that are particularly suitable for the specific shape of the ear canal 7. Furthermore, the headphones 1 may not be in the configuration shown in Figures 1 and 2. Especially during sports, the headphones 1 may shift. In this case, optimal measurement results may not be obtained from the measurement frequencies of the ultrasound 3 emitted for measurement. The MEMS acoustic transducer 2 makes a large number of measurement frequencies from the broadband spectrum 10 available for measurement.

[0114] Here, we further show the sound pressure level 12 that the sound wave 3 generated by the MEMS acoustic transducer 2 can exhibit. According to Figure 3, the sound wave 3 has a sound pressure level 12 of at least 50 dB, preferably 70 dB to 100 dB, or 90 dB or less, thus ensuring sufficient signal quality.

[0115] The broadband spectrum 10 of the MEMS acoustic transducer 2 shown in Figure 3 exhibits a bandwidth and sound pressure level 12 for frequencies 11 in the ultrasonic band ranging from approximately 20 kHz to 80 kHz. The MEMS acoustic transducer 2 can generate sound waves 3 in this wide frequency band, i.e., the broadband spectrum 10. This enables accurate detection of tissue and blood reflexes related to the monitoring of vital parameters such as cardiac and respiratory function. The flexible use of the broadband spectrum 10 is particularly advantageous because the measurement frequency used can be adjusted to suit specific measurement requirements.

[0116] The broad coverage of the ultrasonic bandwidth allows for flexible frequency adjustment and / or selection of measurement frequencies, which helps in the identification of different tissue structures. This is particularly advantageous in the ear canal 7 of the wearer 5. Additionally, the ability to select measurement frequencies from the broadband spectrum 10 improves the signal-to-noise ratio. The optimal measurement frequency can be selected from the broadband spectrum 10, where the selection of the measurement frequency depends on the anatomical structure of the wearer 5 and the placement of the headphones 1.

[0117] By utilizing the MEMS acoustic converter 2, a continuous broadband spectrum 10 shown here can be generated.

[0118] Figures 4 and 5 each show measurement signals 21 that can be used to determine physical function.

[0119] Figure 4 shows a measurement signal 21 having a measurement frequency that exhibits a measurement frequency peak. This means that an ultrasonic wave 3 exhibiting a specific frequency 11 is emitted as the measurement signal 21. Here, the measurement signal 21 is schematically represented in both Figures 4 and 5. Naturally, this measurement signal 21 may have a certain width, for example, 3 kHz. When this measurement signal 21 is generated, other ultrasonic waves 3 with other frequencies 11 are also generated, but these exhibit lower sound pressure levels 12. The measurement signal 21 shown in Figure 4 may exhibit a measurement frequency of, for example, 30 kHz. This 30 kHz can be adjusted to suit the specific anatomical structure of the wearer 5 and / or the specific wearing position of the headphones 1. If the wearer 5 of the headphones 1 is a different person, the measurement signal 21 may exhibit a frequency of, for example, 38.5 kHz due to the different anatomical structure. The measurement signal 21 emitted from the MEMS acoustic transducer 2 may exhibit multiple measurement frequencies, each with a corresponding measurement frequency peak. This allows for multiple measurements to be performed simultaneously.

[0120] Figure 5 shows the measurement signal 21 exhibiting a measurement frequency spectrum. To measure bodily functions, the MEMS acoustic transducer 2 emits the measurement signal 21, exhibiting a broad measurement frequency spectrum as shown in Figure 5. For example, the measurement signal 21 ranges from 20 kHz to 45 kHz. This broad measurement frequency spectrum allows for the simultaneous acquisition and / or measurement of multiple pieces of information.

[0121] As is clear from Figure 5, the measurement signal 21 exhibits a continuous measurement frequency spectrum, enabling the acquisition and / or measurement of diverse information. Furthermore, the measurement signal 21 having the measurement frequency spectrum shown here can exhibit a sound pressure level 12 with a deviation of ±10 dB, particularly ±5 dB. Moreover, the measurement signal 21 shown in Figure 5 can also be adjusted at frequency 11 to match the wearer 5. In Figure 5, only one measurement signal 21 is shown. Alternatively, measurements can be performed using multiple measurement signals 21, each having its own measurement frequency spectrum.

[0122] To set and / or select the optimal frequency 11 of the measurement signal 21, the control unit 4 may execute, for example, a search program and / or a search algorithm. This allows, for example, various measurement frequencies of the measurement signal 21 to be tried and evaluated. The control unit 4 can then select the optimal measurement frequency of the measurement signal 21 that yields the best results. For example, the control unit 4 can select the measurement frequency that exhibits the highest signal-to-noise ratio.

[0123] The embodiment shown in Figure 6 is a schematic cross-sectional view of a MEMS acoustic transducer 2 comprising a piezoelectric element 13 coupled to a diaphragm 14. The piezoelectric element 13 generates vibrations, which are emitted as ultrasonic waves 3 by the diaphragm 14. This arrangement makes it possible to efficiently generate high-frequency sound waves 3 that can be used to accurately detect bodily functions such as heart and respiratory signals.

[0124] As can be seen in Figure 6, the diaphragm 14 is connected to the piezoelectric element 13 via a reinforcing plate 16. The presence of the reinforcing plate 16 ensures that the vibrations of the piezoelectric element 13 are uniformly transmitted to the diaphragm 14. This allows the diaphragm 14 to be displaced in a planar manner, enabling uniform and stable radiation of ultrasonic waves 3. The reinforcing plate 16 thus improves the quality of acoustic radiation and contributes to improving the efficiency and range of the MEMS acoustic transducer 2. Furthermore, the planar displacement allows for the generation of broadband ultrasonic waves 3.

[0125] Furthermore, the piezoelectric element 13 is connected to the coupling element 15 via the spring element 18.

[0126] Furthermore, the acoustic transducer 2 is placed on the carrier unit 17, which forms a stable base for the entire system and holds components such as the piezoelectric element 13, diaphragm 14, reinforcing plate 16, and spring element 18 in place.

[0127] The embodiment of the MEMS acoustic transducer 2 shown in Figure 6 thus exhibits a compact and efficient structure that enables high acoustic output and accurate signal transmission through the interaction of the piezoelectric element 13, diaphragm 14, reinforcing plate 16, spring element 18, and carrier unit 17. The combination of these components ensures high signal quality and the ability to generate a uniform, continuous, and / or stable ultrasonic spectrum. This is advantageous for continuously monitoring the vital parameters of the wearer 5 of the headphones 1.

[0128] The embodiment shown in Figure 7 is a schematic cross-sectional view of a MEMS acoustic transducer 2 comprising at least two piezoelectric elements 13a and 13b, each coupled to a common diaphragm 14. The arrangement of the two piezoelectric elements 13a and 13b enables symmetrical excitation of the diaphragm 14, resulting in uniform and stable emission of the generated ultrasonic waves 3.

[0129] The diaphragm 14 is connected to piezoelectric elements 13a and 13b via a reinforcing plate 16. The presence of the reinforcing plate 16 ensures that vibrations from the piezoelectric elements are uniformly transmitted to and amplified by the diaphragm 14.

[0130] Here, spring elements 18 are positioned between the piezoelectric elements 13a and 13b and the coupling element 15, respectively. Each piezoelectric element 13a and 13b is connected to the coupling element 15 via the spring elements 18.

[0131] By utilizing the MEMS acoustic transducer 2 shown in Figures 6 and 7, ultrasonic waves 3 can be generated and / or detected. For example, ultrasonic waves 3 can be generated and reflected ultrasonic waves 9 can be detected using the same MEMS acoustic transducer 2. However, the headphones 1 may be equipped with at least two MEMS acoustic transducers 2. In that case, the first MEMS acoustic transducer 2 generates ultrasonic waves 3, and the second MEMS acoustic transducer 2 detects reflected ultrasonic waves 9. By utilizing at least one MEMS acoustic transducer 2, it is also possible to generate audible sound waves, for example, to play music. Since ultrasonic waves 3 are inaudible, bodily functions can be determined while music or other sounds are being played. [Explanation of Symbols]

[0132] 1 Headphones 2. Acoustic Converters / MEMS Acoustic Converters 3. Sound waves / ultrasound 4. Control Unit 5. Wearer 6 Ears 7 Ear canal 8 Eardrum 9 Reflected ultrasound 10. Broadband Spectrum 11 Frequencies 12 Sound pressure levels 13 Piezoelectric element 14 Diaphragm 15 coupling elements 16 Reinforcement plate 17 Carrier Unit 18 Spring element 19. Signal Generator 20 Modulators 21 Measurement signal

Claims

1. Headphones (1), in particular on-ear headphones, over-ear headphones, and / or in-ear headphones, At least one acoustic transducer (2) for generating and detecting ultrasound (3), A headphone comprising a control unit (4) capable of determining at least one characteristic of the wearer (5) of the headphones (1), particularly physical function, preferably cardiac function, respiratory function, and / or identifying the wearer (5), and / or performing authentication of the wearer (5), based on the generated and detected ultrasound (3), The headphones are characterized in that the at least one acoustic transducer (2) is a MEMS acoustic transducer (2) capable of generating at least ultrasound (3) within a broadband spectrum (10).

2. The headphones according to claim 1, wherein the MEMS acoustic transducer (2) can generate a broadband spectrum (10) including an audible wavelength spectrum and an ultrasonic spectrum, and is capable of generating audible sound waves (3) and ultrasonic waves (3) as sound waves (3), and the MEMS acoustic transducer (2) can preferably generate sound waves (3) having a broadband spectrum (10) from 3 kHz, 4 kHz, or 15 kHz or higher to 40 kHz, 80 kHz, or 100 kHz or lower.

3. The headphones according to any one of the claims, characterized in that the control unit (4) and / or the MEMS acoustic transducer (2) are designed and / or configured to generate a measurement signal (21) from ultrasound (3) having at least one measurement frequency from the broadband spectrum (10) for determining the physical function.

4. The control unit (4) and / or the MEMS acoustic transducer (2) ensure that the ultrasonic (3) of the measurement signal (21) includes one or more, particularly discrete, measurement frequencies, so that the measurement signal (21) exhibits one or more measurement frequency peaks within the broadband spectrum (10), and / or The headphones according to any one of the claims, characterized in that the ultrasonic (3) of the measurement signal (21) includes a continuous measurement frequency, and is designed and / or configured such that the measurement signal (21) exhibits a wide measurement frequency spectrum within the broadband spectrum (10).

5. The headphones according to any one of the claims, characterized in that the control unit (4) and / or the MEMS acoustic transducer (2) are designed and / or set such that the width of at least one measurement frequency peak of the measurement signal (21) is less than 3 kHz, 2 kHz, or 1 kHz.

6. The headphones according to any one of the claims, characterized in that the control unit (4) and / or the MEMS acoustic transducer (2) are designed and / or set such that the frequency width of the measured frequency spectrum of the measured signal (21) is 1 kHz or more, or 5 kHz or more, or 10 kHz or more, or 20 kHz or more, or 30 kHz or more, or 40 kHz or more, or 50 kHz or more, or 60 kHz or more, or 70 kHz or more, or 80 kHz or more, and / or less than 70 kHz, or less than 60 kHz, or less than 50 kHz, or less than 40 kHz, or less than 30 kHz, or less than 20 kHz, or less than 10 kHz.

7. The headphones according to any one of the claims, characterized in that the MEMS acoustic transducer (2) is designed and / or set such that the sound pressure level (12) of the sound waves (3) that can be generated within the broadband spectrum (10) is 50 dB or more, preferably 55 dB or more, and particularly preferably 70 dB or more.

8. The headphones according to any one of the claims, characterized in that the MEMS acoustic transducer (2) is designed and / or set such that the sound pressure level (12) of the sound waves (3) that can be generated within the broadband spectrum (10) is 90 dB or less, preferably 85 dB or less, and particularly preferably 80 dB or less.

9. The headphones according to any one of the claims, characterized in that the MEMS acoustic transducer (2) is designed and / or configured such that the sound waves (3) that can be generated within the broadband spectrum (10) exhibit a sound pressure level (12) having a deviation of ±10 dB, particularly ±5 dB, around the mean value, especially across the entire broadband spectrum (10).

10. The headphones according to any one of the claims, characterized in that the MEMS acoustic transducer (2) is designed and / or configured such that the sound waves (3) that can be generated within the broadband spectrum (10) exhibit a continuous spectrum, particularly over the entire broadband spectrum (10).

11. The headphones according to any one of the claims, characterized in that the headphones (1) and / or the control unit (4) are equipped with a signal generator (19) capable of generating time-discrete pulse signals, chirp signals, sweep signals, and / or multitone signals for generating ultrasound (3) for determining physical function.

12. The headphones according to any one of the claims, characterized in that the headphones (1), in particular the signal generator (19), comprises an MLS signal generator capable of generating an M-sequence signal, and the MEMS acoustic transducer (2) is capable of generating at least the ultrasound (3) within the broadband spectrum (10) based thereon.

13. The headphones (1) and / or the control unit (4) are equipped with a modulator (20) capable of integrating and / or modulating an electrical signal corresponding to the audible sound wave (3) and an electrical signal corresponding to the measurement signal (21) in the ultrasonic band, and the MEMS acoustic transducer (2) is capable of generating sound waves (3) in the audible frequency band and the ultrasonic band from these modulated signals, as described in any one of the claims.

14. The headphones according to any one of the claims, wherein the MEMS acoustic transducer (2) comprises at least one piezoelectric element (13) and a diaphragm (14) coupled to the at least one piezoelectric element (13), and the at least one piezoelectric element (13) and the diaphragm (14) are coupled to each other via a reinforcing plate (16), so that the diaphragm (14) can be displaced in a planar manner to generate the ultrasonic waves (3).

15. The headphones according to any one of the claims, characterized in that the MEMS acoustic transducer (2) is arranged so that when the headphones (1) are used for a predetermined purpose, the ultrasonic waves (3) are radiated into the ear canal of the wearer (5).

16. The same MEMS acoustic transducer (2) generates the audible sound waves (3) and the ultrasonic waves (3), and / or The same MEMS acoustic transducer (2) can be used to generate and detect the ultrasonic waves (3), and / or The headphones according to any one of the claims, characterized in that the headphones (1) are equipped with a microphone and / or another MEMS acoustic transducer (2), thereby enabling detection of the ultrasonic waves (3) and / or ultrasonic waves (3) generated by the other MEMS acoustic transducer (2).

17. A method for determining and / or identifying and / or authenticating at least one characteristic, in particular physical function, preferably cardiac function and / or respiratory function, of a wearer (5) of headphones (1), especially on-ear headphones, over-ear headphones, and / or in-ear headphones, The MEMS acoustic transducer (2) of the headphones (1) generates at least ultrasound (3) from a broadband spectrum (10), and the MEMS acoustic transducer (2) and / or another microphone detect the ultrasound (3). A method wherein a control unit (4) of the headphones (1) detects at least one feature of the wearer (5) of the headphones (1) based on the generated and detected ultrasound (3).

18. The method according to claim 17, characterized in that, using the MEMS acoustic transducer (2), a measurement signal (21) having one or more measurement frequencies is emitted from a broadband spectrum (10) that can be generated by the MEMS acoustic transducer (2) in order to determine the physical function.

19. A single measurement signal (21) is generated, and its ultrasound (3) exhibits one or more measurement frequency peaks within a broadband spectrum (10), and / or The method according to any one of the claims, characterized in that a single measurement signal (21) is generated, and the ultrasound (3) exhibits particularly continuous measurement frequency peaks within the broadband spectrum (10).

20. The method according to any one of the claims, characterized in that the ultrasonic waves (3) generated by the MEMS acoustic transducer (2) are generated using an M-sequence signal.

21. The method according to any one of the claims, characterized in that the control unit (4) executes a search program and / or search algorithm used to determine the measurement frequency of the measurement signal (21) suitable for the wearer (5) of the headphones (1).

22. Ultrasound (3) is generated such that the width of at least one measurement frequency peak of the measurement signal (21) is less than 3 kHz, 2 kHz, or 1 kHz, and / or The method according to any one of the claims, characterized in that ultrasound (3) is generated, the frequency width of the measured frequency spectrum being greater than 5 kHz, 10 kHz, 20 kHz, 30 kHz, 40 kHz, 50 kHz, 60 kHz, 70 kHz, or 80 kHz and / or less than 80 kHz, or less than 70 kHz, or less than 60 kHz, or less than 50 kHz, or less than 40 kHz, or less than 30 kHz, or less than 20 kHz, or less than 10 kHz, or less than 5 kHz.

23. The method according to any one of the claims, characterized in that ultrasonic waves (3) having a sound pressure level (12) of 50 dB or more, preferably 55 dB or more, and particularly preferably 70 dB or more are generated.

24. The method according to any one of the claims, characterized in that ultrasonic waves (3) are generated having a sound pressure level (12) of 90 dB or less, preferably 85 dB or less, and particularly preferably 80 dB or less.

25. The method according to any one of the claims, characterized in that ultrasonic waves (3) exhibiting a continuous spectrum within the measurement frequency spectrum are generated.

26. The method according to any one of the claims, characterized in that the ultrasonic waves (3) are generated using a signal generator (19).

27. The method according to any one of the claims, characterized in that, in order to generate audible sound waves (3) and ultrasonic waves (3), corresponding electrical signals are integrated and / or modulated using a modulator (20), and the modulated signals are sent to a MEMS acoustic transducer (2) for conversion.

28. The method according to any one of the claims, characterized in that the measurement signal (21) is emitted at intervals of 30 microseconds to 300 milliseconds, particularly at intervals of 1 microsecond to 100 milliseconds.

29. The method according to any one of the claims, characterized in that the ultrasound (3) is generated using a chirp signal, a sweep signal, and / or a multitone signal within the measurement spectrum and / or broadband spectrum (10).

30. The method according to any one of the claims, characterized in that the ultrasound (3) is generated and detected by the same MEMS acoustic transducer (2) in order to determine the aforementioned physical function.

31. The method according to any one of the claims, characterized in that the audible sound wave (3) and the ultrasonic wave (3) are generated using the same MEMS acoustic transducer (2), and it is preferable that the audible sound wave (3) and the ultrasonic wave (3) are generated simultaneously and / or together.

32. The method according to any one of the claims, characterized in that the physical function is evaluated by an algorithm and / or evaluation program, and the algorithm and / or evaluation program is preferably executed by the control unit (4).

33. Use of a particularly broadband MEMS acoustic transducer (2) for a method for determining headphones (1) and / or physical function according to any one of the claims, wherein the MEMS acoustic transducer (2) preferably exhibits at least one feature described in the claim and relating to the MEMS acoustic transducer (2).

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