US 5,113,868 A · Ultraminiature pressure sensor with addressable read-out circuit

Abstract

A capactive pressure sensor suitable for making highly sensitive, low pressure measurements is disclosed. The sensor may be mounted into a 0.5 mm OD catheter suitable for multipoint pressure measurements from within the coronary artery of the heart. The sensor employs a transducer which consists of a rectangular bulk silicon micro-diaphragm several hundred microns on a side by two microns thick, surrounded by a supporting bulk silicon rim about 12 microns thick. Both the diaphragm and the rim are defined by a double diffusion etch-stop technique. The transducer fabrication process features a batch wafer-to-glass electrostatic seal followed by a silicon etch, which eliminates handling of individual small diaphragm structures until die separation and final packaging. An addressable read-out interface circuit may be used with the sensor to provide a high-level output signal, and allows the sensor to be compatible for use on a multisite catheter having only two electrical leads.

Claims20

Dependent claims

A pressure sensing catheter system, comprising:

(a) a catheter;
(b) a pressure sensor at a predetermined location of the catheter;
and
(c) signal conduit means within the catheter for providing a path for signals to be passed between an external monitor and the pressure sensor, the signal conduit means including only two electrical conductors which are connectable to the external monitor,
the pressure sensor including (1) pressure transducer means for converting a sensed pressure into a first electrical signal which is detectable over the signal conduit means by an external monitor, (2) first switching means for selectively controlling when the first electrical signal is generated, and (3) means responsive to at least one command signal from the external monitor for selectively activating the first switching means at a distinct interval of time,
whereby the external monitor may receive separately in time the first electrical signal generated by the pressure sensor.

3 more elements

A microminiature pressure-sensing system, comprising:

an electrically-powered microminiature pressure-sensing apparatus for producing first and second electrical signals at distinct intervals of time, the first signal bearing information about ambient pressure sensed by the apparatus, and the second signal containing information about ambient temperature sensed by the apparatus;
and
signal conduct means for providing a path for electrical power and for the first and second electrical signals to be passed between an external monitor and the pressure-sensing apparatus, the signal conduit means including only two distinct electrical conductors which extend between the apparatus and the external monitor,
the pressure-sensing apparatus including (1) pressure transducer means for converting a sensed pressure at the apparatus into the first electrical signal, (2) first switching means for applying the first electrical signal to the signal conduit means, (3) temperature transducer means for converting an ambient temperature level sensed at the apparatus into a second electrical signal is detectable over the signal conduit means by an external monitor, (4) second switching means for selectively controlling when the second electrical signal is generated, (5) means responsive to command signals from the external monitor for selectively activating the first and second switching means at distinct intervals in time, whereby the first and second signals are transmitted over the two distinct electrical conductors at different intervals in time, whereby the first and second signals do not interfere with one another.

1 more element

Dependencies are inferred from the claim text.

Ultraminiature pressure sensor with addressable read-out circuit

Life of this patent

Ultraminiature pressure sensor with addressable read-out circuit

Life of this patent

Abstract

Claims20