Patent Infringement Doctrine of Equivalents

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Patent InfringementDoctrine of Equivalents

• Prof. Loren
• Fall 2005

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Infringement

• Step one
• Construe the claims
• Sources of information
• Cannons of Construction
• Markman hearings judge issues ruling (subject
  to de novo review on appeal)
• Step two
• Compare the accused product/process
• Every element must be present either
• Literally (literal infringement)
• An equivalent (doctrine of equivalents)

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Tension -Dont want the patent grant to be
hollow -Need to provide notice to the public of
patentees rights to exclude
Claim
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• Catch Phrases from Graver Tank (1950)
• Substantially the same function, substantially
  the same way,
• to reach substantially the same result
  (the function, way, result test)
• Prevent insubstantial changes and substitutions
  from escaping infringement liability
• known interchangeability an important factor

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Warner-Jenkinson v. Hilton Davis (1997)

• Whats the critical claim language?
• Is accused infringer literally within the claim?
• How well does the accused process perform?
• Why isnt this a slam dunk for the patentee?

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Warner-Jenkinson

• Prosecution history estoppel Patentee cannot
  use Doctrine of Equivalents to recapture subject
  matter that she gave up during prosecution to
  obtain the claim from the PTO

Claim
Amended
Proposed claim
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Warner-Jenkinson

• BUT NOTE Narrowing amendments create an
  estoppel only when they are made to address a
  concern that arguably would have rendered the
  claimed subject matter unpatentable

Amended Claim
Amended
Proposed claim
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Warner-Jenkinson

• Hilton Davis ultrafiltration through a
  membrane having a nominal pore diameter of 5-15
  Angstroms under a hydrostatic pressure of
  approximately 200 to 400 p.s.i.g. to thereby
  cause separation
• PTO What about Booth patent, which shows a pH
  above 9.0?
• Hilton Davis ultrafiltration through a
  membrane having a nominal pore diameter of 5-15
  Angstroms under a hydrostatic pressure of
  approximately 200 to 400 p.s.i.g., at a pH from
  approximately 6.0 to 9.0, to thereby cause
  separation

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Warner-Jenkinson

• We place the burden on the patent-holder to
  establish the reason for an amendment required
  during patent prosecution.
• Where no explanation is established the court
  should presume that the PTO had a substantial
  reason related to patentability and
  prosecution history would bar the application of
  the doctrine of equivalents as to that element.

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Warner-Jenkinson

• What about the role of intentional copying as a
  restraint on DOE?
• What time-frame should we use for assessing
  equivalency?
• Determination of equivalence is
• an objective inquiry,
• determined on an element-by-element basis

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Another limit on DOE
Aspect surrendered Upon amendment
(Amended) Claim
Wilson Sporting Goods Co. v. David Geoffrey
Assoc. (Fed. Cir. 1990) Note 1 p. 236
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Festo v. SMC (2002)

• Technology -- piston-driven carriage system
• What are the critical claim elements?
• Pair of sealing rings
• Sleeve made of magnetizable material
• What prompted the amendments that produced these
  critical claim elements?
• Section 112
• What does the accused product have?
• Single sealing ring w/ 2-way lip
• Non-magnetizable sleeve

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Festo

• Trial court no pros. history estoppel,
  equivalent infringement plaintiff wins
• Fed Cir (eventually, en banc)
• estoppel can be created by any patentability
  requirement
• once found, estoppel is a complete bar to
  equivalent infringement as to that element
• What happens at the Supreme Court?
• What reasons for amendment create estoppel?
• Does an estoppel create an absolute bar?

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Festo

• After amendment, as before, language remains an
  imperfect fit for invention. The narrowing
  amendment may demonstrate what the claim is not
  but it may still fail to capture precisely what
  the claim is. -p.243

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So, what equivalents are left?

• Situation element in a claim was amended for
  reasons of patentability, defendant is alleged
  to have infringed. As to the amended element,
  the defendants product is alleged to have an
  equivalent

New technologies, sheds new light.
equivalents unforeseeable at the time of the
amendment and beyond a fair interpretation of
what was surrendered.
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Johnson Johnston (Fed. Cir. 2002)
Disclosed but not claimed

• Claim says
• Aluminum
• Defendant uses
• Steel
• What is the problem for infringement under DOE
  claim?

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Should disclosed but not claimed material be
within the DOE?

• Maxwell
• DOE may not be used
• PTO was deprived of opportunity to consider
  patentability of unclaimed material

• YBX Magnex
• Rule in Maxwell only applicable if the disclosed
  but unclaimed material is distinct from the
  claimed invention
• Overruled by JJ

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Equivalents barred By prior art
Equivalents disclosed but not claimed
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Whats the effect on claim drafting behavior?

• Claim everything you disclose
• Disclose only what you claim
• Judge Raders answer to that?
• Goals
• Notice function of patent claims
• Protective function of DOE
• DOE should not capture equivalents that the
  patent drafter reasonably could have foreseen
  during the application process and included in
  the claims

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Judge Radars view of the proper use of DOE
claim