BASIC LAW FOR
INFRINGEMENT ANALYSIS
Present By:
Daniel J. Kluth, shareholder
Edward J. Brooks III, officer
Schwegman, Lundberg, Woessner & Kluth, P.A.
April 26th, 2001
Copyright: The Schwegman Institute Opinion Seminar Series
What We’ll Cover/Infringement
Analysis
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The When/Why/How of Opinions
Rules of Claim Construction
Literal Infringement
Infringement under the Doctrine of
Equivalents
• Practical Tips for Opinion Practice
What We Won’t Cover Today
• Validity Analysis
• Enforceability Analysis
Overview
• Determining Infringement is a Two-Step
Process
– Claim Construction
• Determining the Meaning of the claim
terms and the scope of the claims
– Comparison of the Properly Construed
Claims to the Accused Device
Who is Asking for an Opinion
and Why?
• Offensive Purpose
– Charge of Infringement
– Support a Cease and Desist Letter
– Support a Complaint filed in Court
• Defensive Purpose
– Charged with Infringement
– Design Around
– Protect Against Willful Infringement
• Market Clearance/Due Diligence
– Assess the Risk of Liability
– Assess the Value of Patent
Competent Opinion
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Outside Independent Counsel
In Writing
List the Facts/Applicable Law
Apply the Facts to the Law
Timeliness
What is the Basis of the Opinion
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Alleged Infringed Patent
File History of the Patent
All Prior Art Cited during Prosecution
A reliable description of the Accused
Device
• Other Possible Evidence
• Reliance on Legal Authority/Scientific
Principals
Liability for the Patent Attorney
• Thoroughness
• Diligence
• Objectiveness
Rules of Claim
Construction/Markman
• Claim Construction as a Matter of Law
• Intrinsic Evidence
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Claim language
Written Description
Accompanying Drawings
Prosecution History
• Extrinsic Evidence
• Inventor/Expert Testimony
• Treatises/Technical Articles
Vitronics/Donaldson/SRI Int’l
• Claim terms are to be given their ordinary and customary
meaning in the field of invention
• When the specification explains and defines a term used in
the claims, without ambiguity or incompleteness, stop there
• Means Plus Function Claims
• Prosecution History Estoppel
Mechanics of Claim Construction
• Claims Chart
– Claims
– Specification
– File History
• Claim Paragraphs
• Support in The Specification
Literal Infringement Analysis
• Applying the Properly Construed Claims to the Accused
Product or Process
• The question of infringement is a question of fact for a jury
• Each and every element must read on the accused device
• Each claim stands on its own
• Means-Plus-Function claims, the accused device must
perform the identical function required by the claim
limitation, and must have identical or equivalent structure
to that disclosed in the specification
Mechanics of Claim Comparison
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Claims Comparison Chart
Copying
Public Notice
Ambiguous/Vague Claims
Reverse Doctrine of Equivalents
• Literal Infringement—The Doctrine in Reverse
• Occurs when all the claim elements of an asserted patent
are “literally” found in the accused device
• May, nevertheless not infringe if the product or process the
product or process is so far changed in principle from a
patented article that if performs the same or similar
function in a substantially different way
• One should return to the specification and claim
interpretation to clearly articulate the substantiality of these
differences
Infringement under Doctrine of
Equivalents
• Equitable Doctrine
• Affords protection to inventions where a product avoids
the literal language of the claim by making a noncritical
change
• Each element contained in a patent claim is deemed
material to defining the scope of the patented invention
• Determine if the differences between the elements of the
claimed invention and the suspect infringing device or
process are “insubstantial”
• Question of Fact
Function-Way-Result/Graver
Tank
• Function-Way-Result Test
– Does the non-literally infringing element perform substantially the
same function, in substantially the same way, to obtain the same
result
• All Element Test/Pennwalt
– Can an equivalent can be found within the Accused Device for
every limitation in the claim
• Hypothetical Claim Test/Wilson Sporting Goods
Another Approach/Hilton Davis
• Substantiality of the Differences
• Were elements of the accused and claimed devices
were known to be interchangeable at the time of
infringement
• If the substitute was not known to be
interchangeable, would the ordinary artisan would
have considered the change insubstantial at the
time of infringement/Pennwalt
Substantiality of
Differences/Timing
• Substantiality of the differences is to be
based on resolving the question of whether
the accused product or process contains
elements identical or equivalent to each
claimed element of the patented invention
• The proper time for evaluating equivalency
is at the time of infringement, not at the
time the patent issued
Other Factors
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Copying
Design Around
Pioneering aspects of the invention
Significant Advantage
Prior Art/File History Estoppel
• Warner Jenkinson/Wilson Sporting Goods/Festo
• Limits the range of permissible equivalents is
limited by the prior art and the file history
• Statements made by the USPTO examiner or the
patent applicant which shed some light on the
scope of the claims
Effect
• Prosecution history estoppel precludes a patentee
from obtaining coverage of subject matter that has
been relinquished during the prosecution
• Complete bar to the application of the doctrine of
equivalents to any claim elements narrowed
during patent prosecution in order to achieve
patentability
• Presumption that the limitation was added for
reasons related to patentability
Unsettled Legal Issues
• Means-Plus-Function language is interpreted to
cover the corresponding structure, material, or acts
described in the specification, and the equivalents
thereof ???
• Only those equivalents expressly set for in the
specification
Festo?
• Certiorari Granted
• Amendments Related to Patentability
– changes needed not only to overcome the prior art
– Changes needed to overcome indefiniteness rejections
• All amendments potentially raise the specter of restricting
the applicant’s available protection under the doctrine of
equivalents
Portfolio IP Presentation given by Tom F. Brennan
jkalis@slwk.com