Doctrine of equivalents and prosecution history estoppel in the wake of Festo case

Presented by: Deepak Gupta

(Festo Corp. v Shoketsu

Kinzoku Kogyo Kabushiki

Co., 535 U.S. 722 (2002) )

Teaser

Imagine two United States patents, both with

the same inventor, the same drawings, the

same written description, the same claims,

the same filing date, and the same issuance

date.

Is there any difference between these

two imaginary patents?

Purpose of Patent System

•The main purpose of the patent system is to promote the progress of science and useful arts.

•Patent law achieves this by performing two functions:

•1. The patentee is given a market monopoly through which he can profit from his invention.

•2. The invention is disclosed to public where public can learn from the invention and build upon it.

•There is a constant push-pull going on

between these two functions.

•i.e., a patentee seeks to maximize the scope of

patent, whereas the public benefits from

limiting the scope of the patent so that more

inventions can be brought out.

Legal concepts involved

•1. Doctrine of equivalents (DOE) – It seeks to

broaden the scope.

•2. Doctrine of Prosecution History Estoppel

(also known as file-wrapper Estoppel) – It

seeks to narrow the scope.

Types of Infringements

•Courts have recognized two types of infringement:

o1. Literal infringement - It exists when the accused device

falls within the literal language of the claim.

o2. The doctrine of equivalents.

DOE

Doctrine of equivalents

•Brief history:

1. Use of concept for first time – Winans v. Denmead (1853).

2. Use of term for first time - McCormick v. Talcott.

Form vs substance(Winans v Denmead)

When a patentee describes a machine then by law he actually covers, not only the precise forms he has described but all other forms which embody his invention.

Graver Tank & Manufacturing Co. v. Linde Air Products Co.

•This doctrine was finally ratified in the 1950

Supreme Court decision of Graver Tank

Mfg. Co. v. Linde Air Products Co.

•Fundamentally, pioneer patents were to be

given a broader range of protection than an

improvement patent.

•Definition of the doctrine of equivalents:

It is an infringement of a patent claim even if it is not literally infringed if the allegedly infringing device or process "performs substantially the same function in substantially the same way to achieve the same result" as the patented invention.

“Function/way/result" test

Image

•The technology at issue was the

production of dyes. 

•Hilton Davis’ had a patent using an

‘ultrafiltration’ process. 

•Warner-Jenkinson developed a similar

dye production process

Warner-Jenkinson Company v Hilton

Davis Chemical Co. [520 U.S. 17(1997)]

Warner-Jenkinson Company v Hilton Davis Chemical Co. [520 U.S. 17(1997)]

•The Supreme Court upheld the viability of the

DOE but imposed two important limitations

on its application.

•First Limitation:

•"Element by Element" Test

•Second Limitation:The second was to enhance the role of prosecution

history in limiting the scope of protection to be given under the doctrine.

This is the known as the doctrine of Prosecution

History Estoppel (also known as file-wrapper

Estoppel).

Image

Festo Corp. v Shoketsu Kinzoku Kogyo Kabushiki Co. [535 U.S. 722]

•Festo Corporation owns two patents for an improved magnetic rodless cylinder:

1. the Stoll Patent; and

2. the Carroll Patent.

•After the examiner rejected the original claims for indefiniteness under 35 U.S.C. §112, so Festo Corp. amended the original claims.

•Shoketsu Kinzoku Kogyo Kabushiki Co.(SMC) made a device similar to Festo's with some changes.

•Since SMC's device falls outside of the literal claims of the two Festo patents, the question at issue is

whether SMC infringed the patents under the doctrine of equivalents.

•The District Court found that Festo's amendments were not related to the examiner's §112 rejections or to avoid prior art, it therefore declined to apply the prosecution history estoppel, and granted Festo's summary judgment motion on the infringement of the Carroll patent.

•A panel of the Court of Appeals for the Federal Circuit affirmed.

•The Supreme Court granted certiorari, remanded to

the Federal Circuit for further consideration in light

of the Court's intervening Warner-Jenkinson

decision.

•After a decision by the original panel on remand,

the Federal Circuit ordered rehearing en banc and

reversed the District Court's ruling.

•The en banc court held that:

•1. Prosecution history estoppel arises from any

amendment that narrows a claim to comply

with the Patent Act, not only from amendments

made to avoid prior art.

Federal Circuit on Festo case

•2. Second, the Federal Circuit analyzed whether

a voluntary claim amendment--one not

required by the examiner or made in response to

a rejection by an examiner for a stated reason -

creates prosecution history estoppel.

1.Furthermore, the court held that when estoppel applies, it stands as a complete bar against any claim of equivalence for the element that was amended.

US Supreme Court

How does it affect our work

•The Festo decision creates some practical problems in drafting patent applications for use in the United States.

•The limitation on the application of the doctrine of equivalents after Festo can be taken care of by avoiding limiting the claims during prosecution for reasons relating to patentability.

•One way would be by filing multiple applications. However, this may be impracticable in many circumstances

Our Work

•1. Prior art search needs to done more thoroughly. A full appreciation of the prior art should help in drafting claims that do not need to be amended during prosecution.

•2. Make sure that the claims are clear and fully enabled before they are filed. Since, unclear or un-enabled claims may need to be amended under the requirements of 35 USC § 112. These amendments may cause the invocation of a prosecution history estoppel as an amendment related to patentability.

•3. When amending claims during prosecution

if possible make an argument for the

patentability of the claims prior to

amendment and state that the reason for

limitation is for commercial, financial or

other reasons not related to patentability.

•4. Consider the possibility of using multiply

dependent claims to create a large number of

claim moieties to cover multiple aspects of

the invention in relatively narrow terms.

Freedom to operate search

•Festo is important for such cases. Whatever, the patentee surrenderd during prosecusion is open for use by others.

•Patent procesuing history is accesible from Patent Application Information Retrieval offered by USPTO.

(http://portal.uspto.gov/external/portal/pair)