Siemens Aktiengesellschaft

Gunther Grabner

Reinhard Lerch

Dietrich Stephani

Fritz Breimesser

A touch selection pad contains a matrix of tactile sensors each of which contains a composite material with a pressure and direction-dependent electric conductivity and a dielectric material forming a capacitor. These are provided with column electrodes and row electrodes. When touched, each of the sensors creates a series circuit comprising a resistor formed of the composite material and a capacitor formed from the dielectric having a capacitance of preferably at least 50 pF. In this matrix of tactile sensors, the pressure-dependent resistance together with the associated fixed capacity serves as the measuring variable. The touch pad due to the small spacing between the sensors has a high resolution. It can be produced in a simple manner by sequentially depositing layers on a metalized carrier by means of a thin-film technique. The row and column electrodes can be etched out of a metalized plastic cover layer and a metalized carrier, respectively, by micro structuring techniques.

Touch selection pad and method of manufacture

An ultrasonic transducer comprises a support body, a piezoelectric layer of a material with a relatively high dielectric constant and high acoustic impedance, a first impedance matching layer and a second impedance matching layer (10). The first matching layer consists of silicon.

Ultrasonic transducer

An ultrasonic sensor for determining objects in air or other gaseous media is disclosed. The sensor comprises a first ultrasonic transducer having a piezoelectric transmitter. A reflector is provided having a concave surface facing the first ultrasonic transducer which forms a segment of an ellipsoid. The reflector has two focal points, the first of which is closer to the reflector and the second of which is near the object to be detected. Between the first ultrasonic transducer and the reflector, a second ultrasonic transducer is provided which is arranged at the first focal point of the reflector. Preferably, the surface of the second ultrasonic transducer facing the reflector forms a spherical segment. By this arrangement, an increase of the receiving aperture is achieved, and objects can be determined which have a normal to the reflection surface inclined with respect to the axis of the sound lobe by an object position angle which is substantially larger than .+-.3.degree.. Additionally, objects with a curved reflection surface can be determined unambiguously.

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Heroldsbach, Germany

Gunther Grabner