All you need to know about file wrapper analysis for patent invalidation search

Patent File Wrapper, as the name suggests, is a file that wraps all the documents involved in prosecution as well as opposition (if any) of a particular patent application. It is the complete documentation of a patent application comprising all the documents related to a patent such as drawings, block diagrams, forms, receipts, etc. Any communication being written or oral that happens between the examiner and the applicant gets recorded in the File Wrapper. The File Wrapper is also popularly known as File History or Prosecution History.

Extracting The Patent File Wrapper
File History of patents can generally be extracted from the official websites of the national Intellectual Property Offices. For example, File Wrapper of US patents can be downloaded from Public Pair website and File Wrapper of a European patent can be downloaded from EP Register of Espacenet. File Wrapper serves as an authentic source of information and proves to be helpful in developing a thorough understanding of the prosecution history.

How To Effectively Study File Wrapper?
An effective and in-depth analysis of the File Wrapper is required during the invalidation study of a patent. File Wrapper includes many documents. Some documents such as issue notification, Issue fee payment, electronic acknowledgment receipt, filing receipt, etc. are not important from the perspective of invalidation. Therefore, some researchers prefer to selectively extract the relevant files which are useful for conducting invalidation search. For a better understanding of prosecution history, we only need to analyze documents pertaining to specification, claims, rejections, arguments, amendments, appeals, a notice of allowance, and opposition proceedings (if any). All these amendments, rejections, and arguments help us in developing a deep understanding of the reason for the grant of the patent and the same help during the invalidation study of the patent under investigation. Further, the File History documents the complete search strategy of the examiner including keywords, classifications, and queries executed. The citations including those disclosed by the applicant as well as cited by the examiner during the examination can also be extracted from Information Disclosure Statement (IDS).

Insights Provided By A File Wrapper To Conduct Invalidation Search
Novelty or Inventive Step
To conduct a good invalidation search, it is most important to comprehend the novelty as well as the inventive step of the invention on the basis of which the patent application materializes into a grant. Most of the time, the novel aspect of the subject patent is present in the “Notice of allowance” issued to a patent application; if not so, then we need to inspect all the rejections given by the examiner and the amendments that the claims of the patent under investigation have gone through. Generally, before a claim is granted, it goes through a series of amendments and once the claim(s) is modified up to the satisfaction of the examiner, it gets granted. Most possibly, the final amendment, after which the application is granted, contains the reason for issuance of the notice of allowance.
There may be times when the reason for grant is neither mentioned in arguments nor in the notice of allowance. In such a situation, we should look for appeals made by the applicant to the concerned appeal board such as PTAB. As 35 U.S. Code § 134 provides to an applicant, whose claims have been twice rejected, to appeal from the decision of the primary examiner to the Patent Trial and Appeal Board. If there exists such an appeal in File History of a patent, the reason for the grant can be extracted from the decision of the appeal board on such appeal.

Opposition Proceedings
Opposition proceedings (if any) famously known as Post-Grant review are also an important part of a File Wrapper. While conducting an invalidation search one needs to ensure that the claims which have been picked up for the study are the updated granted claims. As it is a possibility that the claim(s) could have been opposed and the applicant could have been persuaded to amend the claims to keep patent in-force. One more thing to notice here is that during the opposition proceedings, an applicant is allowed to file multiple Auxiliary Requests and/or the main request containing amended claims to be used during the proceedings, in case the original claims do not meet the patentability requirements.

Relevant Keywords & Classification
File wrapper includes “search information including classification” which provides the information of classifications used by the examiner while conducting the search. These classifications can be utilized for conducting an invalidation search. The information of keywords and synonyms used by examiner given in “Examiner Search Strategy and Results” is also helpful in conducting an invalidation search.

Detail of Cited References
The file wrapper provides the information of references cited by the applicant and examiner. Some references are discussed by the examiner in “non-final rejections” and “final rejections”. It is a very important step in the invalidation search to analyze all the cited references. Analysis of cited references gives a clear indication that which aspect of the claim is not covered by these references and a searcher can focus on that missing aspect to find a relevant reference.

A Real Scenario In Which 102 Prior Art Is Obtained Only By Carefully Analyzing The File Wrapper
Here is a scenario in which we have found a killer prior art by carefully analyzing the file wrapper. The subject patent was related to LCD (Liquid crystal diodes) and we have also analyzed the litigation data in which so many products are infringing on the invention of the subject patent. After analyzing subject patent and litigation data, we have analyzed the file wrapper to ensure the novel element of the subject patent. We have read all the arguments between examiner and applicant discussed in “Non-final Rejections” and “Final Rejections”. In non-final rejections, some patents were discussed and while analyzing those patents in detail, we have come across a patent which was covering all the elements of the claim. However, that text was not discussed by the examiner. That patent was disclosing various embodiments related to LCD. The examiner discussed one embodiment which was not covering the novel element of the claim whereas the text analyzed by us was some different embodiment which was covering all the concept of the subject patent.
We have further continued our search with different strategies such as keyword, classification, inventor, assignee, spider (i.e. forward and backward citation search), and NPL to uncover all existing promising references. Finally, we have noticed that there is only a single 102 prior art reference and that reference was already discussed in non-final rejections of file wrapper. Apart from that, we have also come across some 103 prior art as we believe to uncover all the solutions which can be utilized to invalidate a patent.
From this scenario, we have noticed that file wrapper analysis is very important for conducting an invalidation search. In some scenarios, a careful analysis of file wrapper can provide you a promising prior art at the very initial stage of a project that was missed by the examiner. Also, it provides a lot of insights that are very important for invalidation search.

We have concluded that File Wrapper analysis is an essential part of an invalidation study. A detailed study of File History may reveal loopholes in the prosecution of a patent. It helps in understanding the technical as well as legal boundaries drawn around an invention. As the File Wrapper analysis helps in conducting the study in an efficient manner, the importance of File Wrapper analysis must not be underestimated while conducting an invalidation study. Also, careful analysis of file wrapper helps in providing killer prior art.

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