Another Friendly Reminder from the CAFC – Use of “the Present Invention” is Clear and Unequivocal Evidence of Disavowal

by Mintz Levin - Global IP Matters

Disavowal can occur when a patent holder disavows the full scope of claim terms in the specification or during prosecution (e.g., through the doctrine of prosecution history estoppel).  In either event, disavowal requires clear and unequivocal evidence that the claimed invention includes or does not include a particular feature.  However, “clear and unequivocal” does not mean “explicit.”  Last week, in the case of Poly-America, L.P. v. API Industries, Inc., the Federal Circuit explained that “an inventor may disavow claims lacking a particular feature when the specification describes ‘the present invention’ as having that feature.”  Similarly, the court explained that “an inventor may disavow claims lacking a particular feature when the specification distinguishes or disparages prior art based on the absence of that feature.”

Case Overview:

In the case, Poly-America asserted U.S. Patent No. 8,702,308 for an elastic drawstring trash bag against API Industries’ “conventional” drawstring trash bags (i.e., trash bags where the width of the bottom of the bag and the width of the opening at the top of the bag are the same size).  Although the width of the opening at the top of the patented trash bag was restricted in two of the independent claims to be less than the width of the bottom, independent Claim 10 only required that the two panels and drawstrings of the trash bag be “inseparably joined together at a first short seal and at a second short seal” (emphasis added).  Poly-America asserted that the short seals of Claim 10 only required “a seal that inseparably welds or joins” the drawstrings and the panels of the bag.  However, the Federal Circuit disagreed.

The court noted how the specification stated that “it is important to note that one of the characteristics of the present invention is a reduction in upper width … resulting from the extended short seals” (emphasis in original).  The court also noted how the Abstract stated that “[w]hen the bag of the present invention is in a relaxed state, the reduced upper opening width of the elastic drawstring bag is therefore less than bag proper width,” and that “[e]mbodiments of the elastic drawstring bag contemplated by the present invention have an upper opening with a width that is less than 97% of the width of the rest of the bag (by virtue of the extended short seals).”  The court discussed how the specification explained that prior art bags are difficult to secure over trash can lips, and that the use of extended short seals reduces the width of the opening of the bag, thereby making it easy to fit around a trash can.  Additionally, the court explained that Poly-America distinguished all of the claims from the prior art during prosecution by stating that “[t]he ‘relaxed upper opening width’ of Schneider is the exact same as the ‘bag proper width,’ not less than the ‘bag proper width’ as required by Applicant’s independent claims” (emphasis in original).  Poly-America argued that the terms “relaxed upper opening” and a “bag proper width” were not recited in Claim 10.  However, the court opined that this fact was irrelevant because it was clear that all of the claimed trash bags had a “relaxed upper opening” and a “bag proper width,” when considered in light of the specification.

Ultimately, the court concluded that the specification and the prosecution history “provide clear and unequivocal evidence that the inventor intended to disavow any claim scope encompassing short seals that are not inwardly extended.”  Although the Federal Circuit technically held that the combination of specification and prosecution history provided a restricted claim scope, it is possible that claims may be given a narrowed interpretation based on any one of (a) describing a feature as being part of “the present invention” in the specification, (b) disparaging prior art for lacking a feature, regardless of whether the feature is explicitly claimed, or (c) distinguishing the claims over prior art by asserting that the prior art lacks a feature.


Although a patent applicant may potentially circumvent some prosecution history estoppel issues through the use of a properly-filed continuation or divisional application, the Federal Circuit opinion in Poly-America provides clear caution that the use of the term “present invention” in the specification may be fatal.  Describing the distinctions and benefits of inventions over the art, on the other hand, can be very advantageous.  For example, advantages over the prior art can provide evidence of secondary factors and help to show that the invention is not obvious.  As another example, for those facing subject matter eligibility rejections, advantages over the prior art can help demonstrate that the claimed invention is not routine, conventional, or well known.However, in order to mitigate any adverse effects of discussing an invention’s advantages, benefits over the prior art should be couched within non-limiting modifiers.  For example, benefits can be described with respect to some embodiments, but not all (e.g., “in some implementations of the current subject matter,” “in certain embodiments,” etc.).  Further, during prosecution, patent applicants should separately argue claims with differing features unless the applicant wants to simultaneously limit the scope of all of the claims.

[View source.]

DISCLAIMER: Because of the generality of this update, the information provided herein may not be applicable in all situations and should not be acted upon without specific legal advice based on particular situations.

© Mintz Levin - Global IP Matters | Attorney Advertising

Written by:

Mintz Levin - Global IP Matters

Mintz Levin - Global IP Matters on:

Readers' Choice 2017
Reporters on Deadline

"My best business intelligence, in one easy email…"

Your first step to building a free, personalized, morning email brief covering pertinent authors and topics on JD Supra:
Sign up using*

Already signed up? Log in here

*By using the service, you signify your acceptance of JD Supra's Privacy Policy.
Custom Email Digest
Privacy Policy (Updated: October 8, 2015):

JD Supra provides users with access to its legal industry publishing services (the "Service") through its website (the "Website") as well as through other sources. Our policies with regard to data collection and use of personal information of users of the Service, regardless of the manner in which users access the Service, and visitors to the Website are set forth in this statement ("Policy"). By using the Service, you signify your acceptance of this Policy.

Information Collection and Use by JD Supra

JD Supra collects users' names, companies, titles, e-mail address and industry. JD Supra also tracks the pages that users visit, logs IP addresses and aggregates non-personally identifiable user data and browser type. This data is gathered using cookies and other technologies.

The information and data collected is used to authenticate users and to send notifications relating to the Service, including email alerts to which users have subscribed; to manage the Service and Website, to improve the Service and to customize the user's experience. This information is also provided to the authors of the content to give them insight into their readership and help them to improve their content, so that it is most useful for our users.

JD Supra does not sell, rent or otherwise provide your details to third parties, other than to the authors of the content on JD Supra.

If you prefer not to enable cookies, you may change your browser settings to disable cookies; however, please note that rejecting cookies while visiting the Website may result in certain parts of the Website not operating correctly or as efficiently as if cookies were allowed.

Email Choice/Opt-out

Users who opt in to receive emails may choose to no longer receive e-mail updates and newsletters by selecting the "opt-out of future email" option in the email they receive from JD Supra or in their JD Supra account management screen.


JD Supra takes reasonable precautions to insure that user information is kept private. We restrict access to user information to those individuals who reasonably need access to perform their job functions, such as our third party email service, customer service personnel and technical staff. However, please note that no method of transmitting or storing data is completely secure and we cannot guarantee the security of user information. Unauthorized entry or use, hardware or software failure, and other factors may compromise the security of user information at any time.

If you have reason to believe that your interaction with us is no longer secure, you must immediately notify us of the problem by contacting us at In the unlikely event that we believe that the security of your user information in our possession or control may have been compromised, we may seek to notify you of that development and, if so, will endeavor to do so as promptly as practicable under the circumstances.

Sharing and Disclosure of Information JD Supra Collects

Except as otherwise described in this privacy statement, JD Supra will not disclose personal information to any third party unless we believe that disclosure is necessary to: (1) comply with applicable laws; (2) respond to governmental inquiries or requests; (3) comply with valid legal process; (4) protect the rights, privacy, safety or property of JD Supra, users of the Service, Website visitors or the public; (5) permit us to pursue available remedies or limit the damages that we may sustain; and (6) enforce our Terms & Conditions of Use.

In the event there is a change in the corporate structure of JD Supra such as, but not limited to, merger, consolidation, sale, liquidation or transfer of substantial assets, JD Supra may, in its sole discretion, transfer, sell or assign information collected on and through the Service to one or more affiliated or unaffiliated third parties.

Links to Other Websites

This Website and the Service may contain links to other websites. The operator of such other websites may collect information about you, including through cookies or other technologies. If you are using the Service through the Website and link to another site, you will leave the Website and this Policy will not apply to your use of and activity on those other sites. We encourage you to read the legal notices posted on those sites, including their privacy policies. We shall have no responsibility or liability for your visitation to, and the data collection and use practices of, such other sites. This Policy applies solely to the information collected in connection with your use of this Website and does not apply to any practices conducted offline or in connection with any other websites.

Changes in Our Privacy Policy

We reserve the right to change this Policy at any time. Please refer to the date at the top of this page to determine when this Policy was last revised. Any changes to our privacy policy will become effective upon posting of the revised policy on the Website. By continuing to use the Service or Website following such changes, you will be deemed to have agreed to such changes. If you do not agree with the terms of this Policy, as it may be amended from time to time, in whole or part, please do not continue using the Service or the Website.

Contacting JD Supra

If you have any questions about this privacy statement, the practices of this site, your dealings with this Web site, or if you would like to change any of the information you have provided to us, please contact us at:

- hide
*With LinkedIn, you don't need to create a separate login to manage your free JD Supra account, and we can make suggestions based on your needs and interests. We will not post anything on LinkedIn in your name. Or, sign up using your email address.