Hahn-schickard-gesellschaft Fur Angewandte Forschung E.v.

Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.

Alfons Dehé

Achim Bittner

Daniel Biesinger

Lenny Castellanos

Frank Hedrich

Sophie Billat

Rebecca Wienbruch

Jürgen Wöllenstein

Ananya Srivastava

Christian Weber

A method for detecting aerosol particles in ambient air with a photoacoustic gas sensor, wherein an analysis volume is present in the beam path of a modulable emitter such that the emitter can use modulable radiation to excite aerosol particles in the analysis volume to form sound pressure waves which are detectable by means of the sensor. Using the modulable emitter, the analysis volume is irradiated with the modulated radiation to generate sound pressure waves. The generated sound pressure waves are measured by the sensor, whereby the presence and/or concentration of the aerosol particles in the ambient air is determined on the basis of the measurement results. In some embodiments, the aerosol particles are bioaerosols, such as pollen, spores, bacteria and viruses.

Method for detecting aerosol particles in ambient air, involves irradiating analysis volume with radiation modulated with modulation frequency to generate sound pressure waves

In a first aspect, the invention relates to a photoacoustic gas sensor comprising a gas-fillable detection chamber and a reference chamber arranged laterally adjacent to each other and connected by a sensor channel. A sensor located at or in the sensor channel allows measurement of the photoacoustic signals. Both chambers are preferably located in a plane perpendicular to the emitted IR radiation of the IR emitter which is also comprised. The gas sensor is also formed from a multilayer substrate. In further aspects, the invention also relates to a method of manufacturing a gas sensor and a method of analyzing gas with a gas sensor.

MEMS-based photoacoustic cell

The invention relates to a modulatable infrared emitter comprising a MEMS heating element and an actuator, wherein the actuator triggers shape and/or structure changes of the MEMS heating element. Said change in shape and/or structure of the MEMS heating element may vary the ratio of the emitting area to the total area, thereby producing a change in intensity of the emitted infrared beam. The invention further relates to a manufacturing method for the infrared emitter, a method for modulated emission of infrared radiation using the infrared emitter, and preferred uses of the infrared emitter. In further preferred aspects the invention relates to a system comprising the infrared emitter and a control device for regulating the actuator.

Modeling the emission intensity of an IR emitter by varying the emission surface

The invention relates to a MEMS transducer comprising a vibratable membrane for generating or receiving pressure waves in a fluid in a vertical direction, wherein the vibratable membrane is supported by a carrier and the vibratable membrane exhibits two or more vertical sections which are formed parallel to the vertical direction and comprise at least one layer of actuator material. The end of the vibratable membrane is preferably connected to an electrode, such that the two or more vertical sections can be induced to vibrate horizontally by driving the at least one electrode, or such that an electrical signal can be generated at the at least one electrode when the two or more vertical sections are induced to vibrate horizontally.

MEMS transducer with improved performance

The invention relates to a modulatable infrared emitter comprising an aperture structure, a structured micro-heating element, and an actuator, wherein the aperture structure and the structured micro-heating element are movable relative to each other in parallel planes by means of the actuator to modulate the intensity of emitted infrared radiation. The invention further relates to methods of manufacturing the infrared emitter, a method of modulating emission of infrared radiation using the infrared emitter, and preferred uses of the infrared emitter. In further aspects the invention relates to a system comprising the infrared emitter and a control device for regulating the actuator.

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Reutlingen, Germany

Alfons Dehé