Back to results
US 6,275,048 B1Granted
Capacitive sensor arrangement for a liquid or gaseous medium, and method of making the same
AssigneeDaimlerChrsyler AG
InventorWalter Milli
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeDaimlerChrsyler AG
InventorWalter Milli
Estimating the term…
A capacitive sensor for measuring characteristics of liquid or gaseous media has at least two outer carrier boards and a spacer plate that keeps the two outer boards at an exact dimensionally stable spacing from each other. A sensor capacitor is formed by a hollow space in the spacer plate flanked by two metal coatings forming capacitor plates on the inwardly facing surfaces of the outer boards. Two or more capacitors can be formed by stacking the desired number of boards and spacer plates. Ports are provided for the medium to flow into the hollow space or spaces preferably in the spacer plates. Further ports for pressure equalization inside and outside the sensor are formed either laterally in spacer plate margins or directly in the outer boards. A multitude of such sensors is manufactured simultaneously by printed circuit board techniques that provide the required capacitor plate forming coatings on the inwardly facing surfaces of the boards and the required conductor leads as well as metal screening against adverse field influences. The individual plates and boards are stacked, aligned and bonded and then cut along connector strips to form the individual sensors. Lead-through contacts are formed prior to the cutting.
A capacitive sensor for measuring a characteristic of a liquid or gas, said capacitive sensor comprising at least two carrier boards carrying printed circuit elements, at least one spacer plate between said at least two carrier boards for spacing said carrier boards from each other, a hollow space in said at least one spacer plate, said printed circuit elements comprising metal coatings on inner board surfaces facing said hollow space, said metal coatings forming capacitor plates, at least one first port positioned in said sensor for said liquid or gas to enter into said hollow space inside said sensor, at least one second port positioned in said sensor spaced from said first port for permitting said liquid or gas to exit from said hollow space for pressure equalization in said hollow space relative to pressure outside said hollow space whereby, in operation, said liquid or gas forms a dielectric between said capacitor plates, and wherein said printed circuit elements further comprise conductor leads connected to said capacitor plates for retrieving sensed signals from said capacitor plates.
A method for manufacturing a capacitive sensor having at least one spacer plate between two carrier boards and a hollow space formed by said spacer plate between said carrier boards carrying printed circuit elements including metal coatings forming capacitor plates facing each other across said hollow space to form a sensor capacitor for measuring a characteristic of a liquid or gas in said hollow space, said method comprising the following steps:
Dependencies are inferred from the claim text.