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AIFP

Arthroscopicallyimplantable force probe ®

Designed for medical research, this sensor canmeasure forces in living tissues. Micro-machined,heat treated stainless steel is used to create the tinyelliptical spring structure, which deforms elasticallyunder load.A thermally matched strain gauge bonded to thesteel probe provides a sensitive, linear output pro-portional to applied force. The elliptical cross sectionand ultra-flexible, flat tape cable keep the deviceanchored and oriented within fibrous materials.Specialized instruments have been developed tobury the transducer within tissue substance. Asuture eyelet in the wall of the probe facilitatesremoval. The device is fully encapsulated with vacuum deposited, biocompatible parylene forprotection against saline.Applications include orthopaedic research, tactilesensing, and feedback for electrical muscle stimula- tion.

Approximately the size of a No. 2 pencilpoint, the patented AIFP is designed for placement in very tight areas.

Electrical SpecificationsMechanical Specifications

Excitation 14 milliamps D.C. Full scale (FS) 16 N * Sensitivity 30 mV/ma/N Length 5 mm
section break Non-Linearity +/- 1.5% over 1/2 FS+/- 2.5% over FS Cross section elliptical1.4 mm by1.8 mm Hysteresis 0.3% FS Repeatability 0.3% FS Leads Polyimide andcopper tape cable,20 cm long Temp. Coeff. - Offset +/- .013% FS/C deg. - Span + .0125%/N/C deg. Transverse stiffness Approx. 1.5 N/micron

*

Full scale range may be tailored for specific applications. Fatigue life Approx. 1 million cyclesat 1/2 FS U.S. Patent Nos. 4,993,428 & 5,083,573 and Patents Pending

MicroStrain

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