Fiberoptic Sensor Technologies, Inc.

Northern Telecom Limited

Daniel L Vokovich

Marek T Wlodarczyk

Charles D Anderson

Albert M Straub

Theodore R Mabrey

The invention is related to numerous improvements for fiber optic measuring systems, and principally those utilizing a deformable diaphragm for sensing pressure. One feature of the invention is particularly oriented to automotive engine combustion chamber pressure measurement. For that application, a sensing tip shielding technique is described using a sintered metal porous plug, which reduces temperature fluctuations experienced at the sensing tip and shields the sensing tip from corrosive materials. A technique for compensation of a fiber optic pressure sensor is also described. In that method, a referencing wavelength is partly reflected and partly transmitted past a filter coating at the sensing end of the optical filament. This technique of the sensor provides improved calibration.

Fiber optic pressure sensor systems

A fiberoptic based sensor for patient care use. The sensor includes a catheter placed transcutaneously into a blood vessel which is connected to an external measuring head. A sensing tip of the catheter includes a pressure sensing element and an oxygen saturation measuring element. Features of the invention include novel tip designs, measuring head features, and approaches for enhancing measurement though correlation of the saturation and pressure readings.

Fiberoptic blood pressure and oxygenation sensor

The invention is related to numerous improvements for fiber optic measuring systems, and principally those utilizing a deformable diaphragm for sensing pressure. One aspect of the invention is providing temperature compensation for diaphragm characteristics. Temperature measurement can be achieved by using a light signal having a wavelength distribution which overlaps the cut-off characteristics of a filter positioned at the fiber sensing end. Shifting in the cut-off characteristic in response to temperature modulates the intensity of the reflected back temperature compensation signal. In another approach, temperature is measured through its differential effect on light signals having different launching conditions. With either approach, the temperature measurement is used to calibrate the output of the pressure sensitive diaphragm.

A mechanism for withdrawing magnetic recording tape from a tape carrier (e.g. a cartridge) is disclosed. A boom member supports at least two levers. In the at rest (unengaged) position, rollers, supported by the levers, are positioned in a recess in the tape cartridge and are positioned interior of the tape. When activated, the boom member pivots about its pivot point, thus moving the levers attached to it. The levers move generally away from the cartridge and the rollers attached to the levers engage the tape and pull tape out of the cartridge. The roller supporting ends of the levers engage a lever guide member in such a fashion that the at least two levers move apart. In this manner, a suitable transducer mounted adjacent the lever guide member, can have tape wrapped around itself (less than 360.degree.) for subsequent recording on or playback from the tape. This mechanism is suitable for use with an internal elastic-belt-drive cartridge; when used with such a cartridge, the reels of the cartridge must be driven in their normal manner when extracting tape from the cartridge. The cartridge must also be driven in its normal manner when tape is being fed back into the cartridge. This mechanism is also suitable for use with a non internal elastic-belt-drive cartridge.

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Ann Arbor, MI, United States of America

Daniel L Vokovich