Sensirion Ag

Mettler-toledo Ag

Eidgenossische Technische Hochschule Zurich Nichtmetallische Werkstoffe

Christoph Kleinlogel

Felix Mayer

Ludwig Julius Gauckler

Francesca Venturini

Ralph Steiner-Vanha

Martin Goedickemeier

Claudio Vanoni

An optochemical sensing device has source that emits radiation of a first and a second predetermined intensity, a detector, and a sensitive element that comprises a signal substance. To measure an analyte in a measurement medium, the sensitive element is contacted with the analyte. A first raw signal, which is dependent on the analyte content is obtained by exciting the signal substance with radiation of the first predetermined intensity. At a later time, a second raw signal is also obtained. A comparison of the raw signals yields a comparison value, which is compared against a predetermined limit value. If the comparison value exceeds the limit value, the radiation source is set at the first intensity. If the comparison value is smaller than the limit value, the radiation source is set at the lower second intensity. Using the lower radiation intensity prolongs the life of the sensitive element.

Method of operating an optochemical sensor

A semiconductor wafer () is structured such that fine structures (), such as membranes, bridges or tongues, with a thickness d&#x3c;&#x3c;D are formed, wherein D designates the thickness of the semiconductor wafer (). Then particles of a desired material are applied. A temporal or spatial temperature gradient is generated in the semiconductor wafer (), e.g. by progressive heating. In such a heating process the fine structures heat up more quickly and become hotter than the remaining wafer because they have a smaller heat capacity per area and cannot carry off heat as quickly. In this manner, the fine structures can be heated to a temperature that allows a sintering of the particles. For coating the semiconductor wafer () is brought into a reactor (). A precursor compound of a metal is provided and fed to the reactor (), where a reaction takes place during which the metal is transformed to a final compound and is deposited in the form of particles on the semiconductor wafer ().

Method for applying selectively a layer to a structured substrate by the usage of a temperature gradient in the substrate

The invention relates to a flow sensor comprising a substrate with integrated heat source and temperature sensors. Solder bumps are arranged on the heat source and the temperature sensors and the substrate is attached to the outside of a tube using flip chip technology. Preferably, the outside of the tube is structured for being wetted at appropriate positions by the solder. This allows to assemble the sensor easily and accurately.

Flow sensor and method for producing the same

The invention relates to a process for production of a sintered oxide ceramic of composition Ce M D O with dense structure without open porosity or with a predetermined porosity. The first doping element M is at least one element of the group consisting of the rare earths but M&ne;Ce, alkali and earth alkali metals. The educts are used with a second doping element D of at least one metal of the group consisting of Cu, Co, Fe, Ni and Mn, in the submicron particle size or as a salt solution, and sintered at a temperature in the range of 750-1250&deg; C. into an oxide ceramic with extremely fine structure of a grain size of maximum around 0.5 &mgr;m.

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Zurich, Switzerland

Christoph Kleinlogel