Ndm Corporation v. Hayes Products, Inc., and Joseph H. Johnson

NDM Corporation appeals from a judgment in a patent infringement action that various claims of medical electrode patents which had been assigned to NDM were invalid for obviousness. We affirm.

NDM began, in 1969, to develop medical electrodes for use in the electrocardiographic monitoring of heart patients. Initially, NDM attempted to manufacture a “dry” electrode that would be activated by moisture in the patient’s skin, rather than by application of a “wet” electrode gel. These efforts proved unsuccessful and NDM subsequently decided to develop an improved “wet” electrode.

The first product of these efforts was U.S. Patent No. 3,696,807 (“the ’807 patent”), filed on February 13, 1970, issued on October 10, 1972. In laymen’s terms, the ’807 medical electrode patent was a rigid, nonconductive electrode gel cup which had a snap fastener mounted in its base. An elastic sheet covered the cup. This elastic, when pressed against a patient’s skin, would adhere, forming a seal. Because of this seal, electrolyte gel remained in the cup, rather than leaking and causing the electrode to become loose. The snap fastener provided conduction. Increased adhesion facilitated long-term cardiac…