Infringement & the Doctrine of
Equivalents I
Class Notes: February 27, 2003
Law 677 | Patent Law | Spring 2003
Professor Wagner
Today’s Agenda
1. Basics of Infringement
2. The Doctrine of Equivalents
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The Basics of Infringement
1. The patent right: the right to exclude others
from . . .
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•
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Making
Using
Selling
Offering to sell
Importing
2. Categories of Infringement
a) Direct Infringement
b) Indirect Infringement [March 20]
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The Basics of Infringement
1. The patent right: the right to exclude others
from . . .
•
•
•
•
•
Making
Using
Selling
Offering to sell
Importing
2. Categories of Infringement
a) Direct Infringement
b) Indirect Infringement [March 20]
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The Basics of Infringement (2)
1. Forms of Direct Infringement
a) Literal infringement
b) Infringement via the Doctrine of Equivalents
Literal Infringement => consider this claim . . .
1. A writing implement comprising:
A wooden cylinder with a hollow core
A cylinder of graphite in said hollow core
A small cylinder of eraser material attached to one end of the
wooden cylinder
Which of the following infringes the claim:
•
•
•
A wooden pencil with a small metal clip for shirt-pocket
storage
A plastic pencil (body made of plastic)
A pencil without an eraser
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The Doctrine of Equivalents
Winans v Denmead (1853)
• What was significant about the Winans invention?
• Why did the Court find infringement by Denmead?
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The Doctrine of Equivalents
Graver Tank v Linde (1950)
• Technology: welding fluxes
• Invention: alkaline earth metal + calcium fluoride
• Accused: non-alkaline earth metal + calcium fluoride
Why are these facts relevant to infringement?
1. Alkaline and non-alkaline metals performed similarly
2. The prior art suggested that even non-alkaline metals
would work
3. No evidence of independent testing by Linde
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The Doctrine of Equivalents
The Influence of Graver Tank - establishes modern DOE
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The test for DOE: when the accused device performs “substantially
the same function in substantially the same way to achieve
substantially the same result” (“Function-Way-Result test”)
“What determines equivalency must be determined against the
context of the patent, the prior art, and the particular circumstances
of the case”
“Equivalence, in the patent law, is not the prisoner of a formula and
is not an absolute to be considered in a vacuum.”
“An important factor is whether persons reasonably skilled in the art
would have known of the interchangeability of an ingredient not
contained in the patent with one that was.”
A finding of equivalence is a determination of fact
“The record contains no evidence that [the accused device] was
developed as the result of independent research experiments.”
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The Doctrine of Equivalents
Graver Tank, continued.
• How does the majority describe the purpose/use of
the DOE?
o Would a patent without DOE be a “hollow and useless thing”?
• What is the dissent’s primary objection?
o Why does the dissent note the possibility of ‘reissue’?
• Are you convinced?
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The Doctrine of Equivalents
Warner-Jenkinson v Hilton Davis (1997)
o Key limitation: “a pH of approximately 6.0 to 9.0”
o Accused process: pH of 5.0
• Question 1: Does the DOE survive the 1952 Act?
• Question 2: What are the boundaries of the DOE?
o The court “establishes” the “all-elements-rule”: the DOE is
to be applied on an element-by-element basis. (Note that
this had been the law of the Federal Circuit since 1987.)
– Does the ‘all elements rule’ reconcile the tension
between the DOE and the notice function of claims?
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The Doctrine of Equivalents
Warner-Jenkinson v Hilton Davis (1997)
1. The court declines to determine the appropriate
‘linguistic framework’ for the DOE
2. The DOE remains a question of fact, but see ‘famous
footnote 8’ (p. 898)
3. Whether the DOE applies is unrelated to the mental
state of the infringer (Why?)
4. Prosecution history estoppel (PHE) survives, with a new
‘presumption’. (Why?)
5. The DOE may apply to any technology, whether known
or unknown at the time of filing. (Why is this
important?)
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The Doctrine of Equivalents
What is the ‘best’ argument or explanation for
the DOE?
1. Equity/Fairness: An inventor’s rights would be
valueless without DOE.
2. Furtherance of the Law’s Purpose: Allowing
‘equivalent’ copies of patented inventions
undermines the entire system.
3. (Broad) Claim Construction: we presume patentees
have patented all they are entitled to.
Does any of these justify the costs of the DOE?
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Next Class
Infringement & the Doctrine of
Equivalents II
The All Elements Rule
Means-Plus-Function Claims
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