Often in the course of analyzing a patent, one or more claim terms are difficult to interpret in light of the patent specification, and so in that case it can sometimes be helpful to review the patent’s prosecution history (aka “file wrapper” or “file history”) to ascertain the proper scope for ambiguous terms. Additionally, during prosecution the applicant or the applicant’s representative may disclaim specific scope, whether through explicitly doing so during arguments and/or through making a narrowing amendment to a claim to overcome an examiner rejection. The patent owner will likely be precluded from invoking the doctrine of equivalents to broaden the scope of the claim to cover subject matter ceded by this narrowing amendment. This is often called “prosecution history estoppel”, and it is an important reason to normally include prosecution history review as part of a complete patent analysis. There are many other reasons to review a patent’s prosecution history, many having to do with review of applicant patent practitioner conduct or procedural issues.
However, when reviewing the prosecution history specifically to facilitate determination of claim interpretation, one can narrow the scope of the review in order to hasten the review process, and this allows for review of only specific documents in the overall history’s collection of documents. I have found through practice that using a browser with search result highlighting, one can quickly gather the relevant prosecution history documents from the USPTO’s Public PAIR system.
For this example, I have picked my handy favorite patent number 7654321 (it’s also in a technology area outside of my comfort zone).
1. Use PAIR to pull up information on the patent under review, then select the “Image File Wrapper” tab.
2. Next use the browser’s search result highlighting to find the prosecution history documents of interest. There are mostly documents that you can safely ignore in this review, and I have found a specific set of keywords that I leverage which are helpful in collecting the relevant documents. These keywords are “claim” (for claims and the final index of claims), “amend” (for amendments and arguments), “reject” (for examiner rejection), “allow” (for notice of allowance and the associated examiner feedback), “interview” (for outcome and information pertaining to an interview between the examiner and the applicant), “disclaim” (for a terminal disclaimer, because an applicant might argue claim scope), and “action” (in case an office action was missed through searching for “reject”). The first three keywords will capture everything in the majority of cases. Obviously, for a more thorough prosecution history review, you’ll want to review other documents, such as those pertaining to abandonment, information disclosure statements, petitions, declarations, and the like. However, in a review which concentrates on specific claim term interpretation, only this limited subset of documents will be of particular relevance. For each document of interest, select the associated checkbox in the far right-hand PDF column.
3. Once all desired documents have been selected, activate the PDF button in the top row and save this PDF file (with whatever name you find helpful) so you can review its contents.
4. Review the downloaded PDF file. While it is helpful to have context of the examiner’s rejection rationale, it is only important what the applicant (or representative) files, argues, and amends.
The associated PDF file is available for download, if you’d like to see more detail: US7654321 (ser no 11616583) – partial file history.
In this example case, only 20% of the total prosecution history documents need to be acquired and reviewed using the method described above.