Two types of infringement exist for any patent claim: literal infringement
and infringement under the doctrine of equivalents.
On a side note, if a specification discloses an algorithm in functional terms, arguably the accused device would only infringe if it employs an identical algorithm because literal infringement
under [section] 112 [paragraph] requires identity of function.
and ruling on literal infringement
on summary judgment, district courts
(59) The court found, however, that [section] 112, paragraph 6, equivalence differs from the doctrine of equivalents in that [section] 112, paragraph 6, equivalence may lead only to a finding of literal infringement
. (60) As previously noted, no support for this reading can be found in the statute.
occurs when every element of the claim, as construed by the court, is found exactly in the accused device." (9) When an accused device does not literally infringe a patent, the courts may find the accused infringer to have infringed a patent under the doctrine of equivalents.
CTC's model X500 pasta maker was ruled a literal infringement
of claim 6 of the Popeil patent, the claim that includes an egress opening in the extrusion chamber.
claim) precludes a finding of literal infringement
1998) ("Literal infringement
requires that the accused device contain each limitation of the claim exactly; any deviation from the claim precludes a finding of literal infringement
." (citing Cole v.
Although it found no literal infringement
, the Federal Circuit panel affirmed the district court's finding of infringement under the doctrine of equivalents.(162) Judge Schall observed that even when an accused device does not literally infringe a patent claim, it may still infringe under the doctrine of equivalents "if the differences between the claim and the accused device are insubstantial."(163) The district court had found that differences between the use of multiple random numbers and a multistep process of the WMS 400 and the single random number and direct process of selecting a reel stop position claimed by the Telnaes patent were insubstantial.(164)
1987) (in banc) (reasoning that, if the test for literal infringement
relied upon the literal breadth of means-plus-function language in the claims, then "any and every means which performs the function specified in the claim [would] literally satisf[y] that limitation").
to literal infringement
would link the scope of the patent to the extent
(19) Graver Tank held that not to recognize any infringement beyond literal infringement
"would be to convert the protection of the patent grant into a hollow and useless thing." (20) The Court further recognized that to do otherwise "would be subordinating substance to form" (21) and would permit one to "practice a fraud on a patent." (22) After endorsing the doctrine of equivalents as a necessary component of patent law, Graver Tank articulated the test for applying the doctrine commonly known as the "function-way-result" test.