Doctrine of Equivalence Supplement: Johnston v. IVAC Corp. (JWB)

The Case

• Turner developed thermometer probe cover that stays on, owned by AMEC
• District Court of Southern California -- summary judgment that IVAC's thermometer probe covers do not infringe
• Summary judgment when the defendant carries of burden of "pointing out to the district court that there is an absence of evidence to support the nonmoving party's case"
  • IVAC convinced court that AMEC failed to prove infringement literally or by equivalence

Patent

• AMEC: metal probe had sharp metal hook to keep probe cover on
• IVAC: ring on metal probe to keep probe cover on via friction (intentionally left out sharp edge to allow probe cover to be removed)

Ruling

• Affirmed
• To establish infringement of a patent, every limitation set forth in a claim must be found in an accused product or process exactly or by a substantial equivalent

Literal Infringement

• Mere assertion of similarity in the patented and accused devices is insufficient to create a genuine factual issue
• Where a claim does not read on an accused device exactly, there can be no literal infringement

Section 112 (Means Plus Function)

• An element of a claim described as a means for performing a function, if read literally, would encompass any means for performing the function
• Section 112 Paragraph 6 operates to cut back on the types of means which could literally satisfy the claim language
• It does not extend the element to equivalent functions

Doctrine of Equivalents

• AMEC does not assert a friction fit is equivalent to an inscription fit
• Instead, AMEC asserts that IVAC devices perform inscription fit with equivalent structure
  • No evidence for such a claim