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US 5,328,551 AGranted
Method of making high output strain gage
AssigneeEaton Corporation
InventorJohn Kovacich
Life of this patent
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Abstract
A method of making a foil-type electrical resistance strain gage having a gage factor of at least 4. A PtW foil is adhesively bonded to a polyimide substrate with an FEP adhesive cured under heat and pressure. The foil is spin-coated with a positive photoresist, masked, and exposed to ultraviolet light. The exposed photoresist is then developed, permitting wet etching of the foil to form a gage pattern on the substrate, which is then preferably cured.
Claims7
A method of making high output strain gages comprising:
- (a) providing a substrate or base of plastic material;
- (b) providing a thin foil of material consisting essentially of an alloy of tungsten and platinum (PtW) and adhesively bonding the foil to the substrate with a chemically inert adhesive;
- (c) applying heat and pressure to said adhesive bonding;
- (d) applying a photoresist coating to said foil;
- (e) masking said photoresist to a desired gage pattern and exposing the unmasked portion;
- (f) developing the unmasked photoresist and forming a gage pattern on said foil of said photoresist;
- and,
- (g) wet etching said foil with a mixture of nitric acid, hydrochloric acid, and water and forming a gage pattern with bonding pads in said adhesive and said substrate;
- (h) attaching electrical leads to said bonding pads.
6 more elements
Dependencies are inferred from the claim text.