In a November 6, 2024 opinion in Certain Computing Devices Utilizing Indexed Search Systems and Components Thereof, the U.S. International Trade Commission (“ITC”) held that statements, disclaimers, and positions taken during the prosecution of a later patent apply to the construction and interpretation of the same term in an earlier related patent. Using this standard, the Commission found no violation of Section 337 of the Tariff Act of 1930, because a disputed claim term’s scope in an earlier asserted patent was narrowed by the applicant’s disclaimer in a later related patent.

The Asserted Patents and Claims

X1 Discovery, Inc. initiated the ITC investigation by filing a complaint against seven respondents, alleging violations of Section 337 based on infringement of U.S. Patent Nos. 8,498,977 (“the ’977 Patent”) and 8,856,093 (“the ’093 Patent”). These patents relate to systems and methods for efficient search indexing. The patents share a common specification and claim priority to the same parent application shown below. In addition, the ’093 Patent had a child patent, U.S. Patent No. 9,633,139 (“the ’139 Patent).

Key claims in the’977 Patent contain the phrase “wherein the first string and the second string are non-adjacent in at least one of the identified documents,” as shown below:

1. A computerized method of selectively executing a command, the method comprising:

. . .

identifying a first group of the plurality of documents including the first string,

identifying a second group of the plurality of documents including the second string, and

identifying one or more of the plurality of documents that are included in both of the first and second groups, wherein the first string and the second string are non-adjacent in at least one of the identified documents.

19. A search apparatus stored on a non-transitory computer-readable medium, the search apparatus comprising instructions configured to be executed by a computing device in order to perform operations comprising:

. . .

incrementally identifying a set of one or more of the documents included in both the first group of documents and the second group of documents as each successive character of the first search string and the second search string is received respectively in the first search field, wherein the first string and the second string are non-adjacent in at least one of the identified documents; and

displaying an indication of at least one of the identified documents.

Of particular interest here, in a November 2015 Response to an Office Action regarding the application for the ’139 Patent ― a response filed over two years after the ’977 Patent issued ― the applicant sought to avoid a rejection of the claims based on prior art by stating that “[t]here is no teaching or suggestion of searching content of a document itself, such that the search results would include ‘the first partial search string and the second partial search string [are] non-adjacent in at least one of the identified documents.’” (Emphasis added.)

Claim Interpretation and The Accused Products

The products accused of infringing the ’093 and ’977 Patents in the ITC included electronic devices utilizing software with two search features. In a motion for summary determination of non-infringement, the respondents argued that the statements made during prosecution of the ’139 Patent applied to the claims of the earlier issued ’977 Patent , and required that the claims applied only to software that searched the contents of a document. The respondents provided evidence that the accused software did not search the contents of documents, and therefore did not infringe the claims. X1 Discovery did not provide any contrary evidence regarding this feature of the accused products. Thus, the respondents’ non-infringement argument turned on the interpretation of this specific claim language.

Summary Determination

In his Initial Determination, ALJ Elliot denied summary determination of non-infringement of the ’093 Patent, finding genuine disputed issues of material fact. However, ALJ Elliot granted summary determination of non-infringement of the ’977 Patent based on his claim construction of the disputed term “non-adjacent in at least one of the identified documents.” In doing so, ALJ Elliot found there was a disclaimer of the scope of this disputed term in the later-filed ’139 Patent. ALJ Elliot applied the disclaimer to the same term in the ’977 Patent and found non-infringement.

X1 Discovery sought review of the Initial Determination’s summary finding of noninfringement of the ’977 Patent.

Application of a Disclaimer From a Later Patent to an Earlier Related Patent

X1 Discovery argued that Federal Circuit precedent does not support applying disclaimers from a later patent to an earlier patent. The Commission, however, did not agree. Relying on Federal Circuit rulings in Capital Machine Co. v. Miller Veneers and Microsoft Corp. v. Multi-Tech Systems, Inc., the Commission held that a disclaimer from a later patent applies to the same term in an earlier related patent.

In Capital Machine Co., the Federal Circuit held that the prosecution histories for three of the six asserted patents included applicant statements that disclaimed the scope of the common claim term “a flitch.” The Federal Circuit applied the disclaimer from the later patents to the earlier patents, citing Microsoft and stating “[w]e have held that the prosecution history regarding a claim term is pertinent when interpreting the same term in both later-issued and earlier-issued patents in the same family.”

Applying this standard to the facts in the investigation, the Commission found the scope of the term that appeared in both the ’977 and ’139 Patents was limited to searching the content of a document. The Commission found that the November 2015 Office Action Response in the later-issued ’139 Patent included clear and convincing statements that searching the contents of a document is required for the “non-adjacent in at least one of the identified documents” claim limitation. The Commission further found that the disclaimer from the later ’139 Patent applied to the same term in the earlier related ‘977 Patent.

In view of this interpretation of the claims, and the uncontroverted evidence regarding the accused products, the Commission found there was no violation with respect to the ’977 patent because the accused software did not search the contents of documents.

Takeaways

A prosecution history disclaimer can apply to all uses of a claim term in a patent family ― regardless of when the statement was made. This is almost certainly the case for related patents that share the same specification.

In assessing the interpretation of claims in a patent, practitioners should include a careful analysis of the prosecution history of any child applications. Statements made in prosecution of later filed continuation patents may reveal limitations of the claims not identified in the file history of the patent itself or its parent applications.