Cordis Europa N.v.

Microtel, B.v.

U.S. Philips Corporation

Johnsondiversey, Inc.

Piet Bergveld

Gerrit Koning

Adrianus J Sprenkels

Wouter Olthuis

Gerardus Rudolph Langereis

A system for characterizing a liquid comprises a sensor for providing an electrical output signal depending on a characteristic of the liquid, and a processing unit for processing the output signal of the sensor to obtain characterizing data of the liquid. The sensor is made as a single sensor/actuator device and can be connected in a plurality of manners to the processing unit. In at least some of these connecting manners the processing unit is adapted to actuate the sensor/actuator device and to process the output signal of the sensor/actuator device to obtain different characterizing data of the liquid.

System and methods for characterizing a liquid

This invention provides an electroacoustic transducer and a method of making it. The transducer according to the invention comprises a substrate of a semiconductor material with a recessed portion. A membrane is stretched across the recessed portion, which membrane is set in vibration in response to an input signal comprising audio and/or ultrasonorous frequencies. A pair of electrodes is provided, which form a capacitor, and between which an electric field is present. The electrodes are so arranged relatively to the membrane that the capacitance of the capacitor can vary under the influence of vibrations of the membrane, so that acoustic signals are converted into electric signals. A layer of an electrically insulating material functions as a carrier for an electric charge to provide an auxiliary electric field between the electrodes. The transducer is characterized in that the peripheral edge of the substrate, which is raised relatively to the recessed portion, has a set of openings formed in it, each extending through the substrate. The membrane is attached through the openings to the peripheral edge.

Electroacoustic transducer of the so-called 'electret' type, and a

An in vivo electrochemical monitoring device is formed by a catheter-like member which terminates in a closed end having a wall with a fixed opening to admit fluid to be tested, such as blood in an artery. An electrochemical sensor, such as an ISFET device for monitoring the concentration of a particular ion in blood, is mounted inside the tube at a fixed location below the opening preferably a larger sensing chamber. An infusion channel in the tube is arranged to flood the sensor with a fluid of known chemical properties so that the sensor output can be calibrated. Under pressure the calibration fluid expels the test fluid out of the tube or chamber via the fixed opening. A method of constructing a suitable chamber on an ISFET wafer is also disclosed.

Method of making an electrochemical sensing cell

An in vivo electrochemical monitoring device is formed by a catheter-like member which terminates in a closed end having a wall with a fixed opening to admit fluid to be tested, such as blood in an artery. An electrochemical sensor, such as an ISFET device for monitoring the concentration of a particular ion in blood, is mounted inside the tube at a fixed location below the opening preferably a larger sensing chamber. an infusion channel in the tube is arranged to flood the sensor with a fluid of known chemical properties so that the sensor output can be calibrated. Under pressure the calibration fluid expels the test fluid out of the tube or chamber via the fixed opening. A method of constructing a suitable chamber on an ISFET wafer is also disclosed.

Electrochemical sensing apparatus with in situ calibration

A device for measuring a quantity which influences a field-effect transistor which is included in a measuring circuit as a variable resistance. To compensate for temperature-dependent changes of the field-effect transistor, an auxiliary signal, having a frequency located outside the frequency range of the quantity to be measured, is applied to the transistor. The two signals are separated from one another again after having been processed by the measuring circuit.

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Enschede, Netherlands

Piet Bergveld