Apparatus for detecting a proper wearing status of a safety belt of a safety belt assembly in a motor vehicle includes a sensor device which is at least partially disposed in or on the safety belt and configured to output a sensor value as a function of a dependency on a disposition of the safety belt. An evaluation device determines in response to the sensor value output by the sensor device, whether an occupant of the motor vehicle properly wears the safety belt.

A piezoelectric micromachined ultrasonic transducer (pMUT) device may include a piezoelectric membrane transducer designed to have lower sensitivity to residual stress and reduced sensitivity to geometric variations arising from the backside etching process used to release the membrane. These designs allow some of its key feature to be adjusted to achieve desired characteristics, such as pressure sensitivity, natural frequency, stress sensitivity, and bandwidth.

A sound transducer has a diaphragm cup, a transducer element, and a housing, the diaphragm cup having a diaphragm and a wall. The diaphragm, the wall, and at least one housing part are formed in one piece as a fiber-plastic composite component. At least one first region of the fiber-plastic composite component is reinforced with fibers, and at least one second region of the fiber-plastic composite component is free of fibers, so that waves in the fiber-plastic composite component are at least partly reflected at a transition from the at least one first region to the at least one second region.

A sound transducer has a diaphragm cup, a transducer element, and a housing, the diaphragm cup having a diaphragm and a wall. The diaphragm, the wall, and at least one housing part are formed in one piece as a fiber-plastic composite component. At least one first region of the fiber-plastic composite component is reinforced with fibers, and at least one second region of the fiber-plastic composite component is free of fibers, so that waves in the fiber-plastic composite component are at least partly reflected at a transition from the at least one first region to the at least one second region.

Ultrasonic transducers that include membrane films and perforated baseplates. An ultrasonic transducer includes a baseplate having a conductive surface with a plurality of apertures, openings, or perforations formed thereon or therethrough, and a membrane film having a conductive surface. The membrane film is positioned adjacent to the apertures, openings, or perforations formed on or through the baseplate. By applying a voltage between the conductive surface of the membrane film and the conductive surface of the baseplate, an electrical force of attraction can be created between the membrane film and the baseplate. Varying this applied voltage can cause the membrane film to undergo vibrational motion. The dimensions corresponding to the size and/or shape of the apertures, openings, or perforations formed on or through the baseplate can be varied so that different regions of the baseplate produce different frequency responses, allowing the net bandwidth of the ultrasonic transducer to be increased.

Ultrasonic transducers that include membrane films and perforated baseplates. An ultrasonic transducer includes a baseplate having a conductive surface with a plurality of apertures, openings, or perforations formed thereon or therethrough, and a membrane film having a conductive surface. The membrane film is positioned adjacent to the apertures, openings, or perforations formed on or through the baseplate. By applying a voltage between the conductive surface of the membrane film and the conductive surface of the baseplate, an electrical force of attraction can be created between the membrane film and the baseplate. Varying this applied voltage can cause the membrane film to undergo vibrational motion. The dimensions corresponding to the size and/or shape of the apertures, openings, or perforations formed on or through the baseplate can be varied so that different regions of the baseplate produce different frequency responses, allowing the net bandwidth of the ultrasonic transducer to be increased.

This invention provides a noise absorption method and device with an adjustable conical shaped annular aperture on a Helmholtz resonator composed of a Helmholtz resonant cavity, a resonance control package, a sensing & actuating modules and a controller. The resonant cavity harvests noise energy by tracking of the noise resonance frequency which is achieved by adjusting the aperture openness between a movable conical shell and the resonant cavity according to a resonance control algorithm of combination of FFT (Fourier Fast Transform) adjustment and PLL (Phase-Locked Loop control) adjustment.

Meanwhile, the controller applies a driving current into a coil attached to the movable conical shell based on DXHS (Delayed-X Harmonic Synthesizer) algorithm, so that harvested noise energy on the movable conical shell can be absorbed with maximum efficiency. Additionally, a part of the noise energy is dissipated by resonant air friction flowing through the annular aperture on the cavity.

This invention provides a noise absorption method and device with an adjustable conical shaped annular aperture on a Helmholtz resonator composed of a Helmholtz resonant cavity, a resonance control package, a sensing & actuating modules and a controller. The resonant cavity harvests noise energy by tracking of the noise resonance frequency which is achieved by adjusting the aperture openness between a movable conical shell and the resonant cavity according to a resonance control algorithm of combination of FFT (Fourier Fast Transform) adjustment and PLL (Phase-Locked Loop control) adjustment.

Meanwhile, the controller applies a driving current into a coil attached to the movable conical shell based on DXHS (Delayed-X Harmonic Synthesizer) algorithm, so that harvested noise energy on the movable conical shell can be absorbed with maximum efficiency. Additionally, a part of the noise energy is dissipated by resonant air friction flowing through the annular aperture on the cavity.

A one-piece diaphragm and ring for a stethoscope chestpiece is disclosed herein. The one-piece diaphragm and ring includes a diaphragm portion having a flat disk shape; and a ring portion connected to an outer periphery of the diaphragm portion, the ring portion being integrally formed with the diaphragm portion, and the ring portion configured to be attached to a rim of a chestpiece body portion. A chestpiece of a stethoscope that includes the one-piece diaphragm and ring is also disclosed herein.

A one-piece diaphragm and ring for a stethoscope chestpiece is disclosed herein. The one-piece diaphragm and ring includes a diaphragm portion having a flat disk shape; and a ring portion connected to an outer periphery of the diaphragm portion, the ring portion being integrally formed with the diaphragm portion, and the ring portion configured to be attached to a rim of a chestpiece body portion. A chestpiece of a stethoscope that includes the one-piece diaphragm and ring is also disclosed herein.