X1 Discovery Inc v. Microsoft Corp

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: X1 Discovery, Inc. (Delaware)
  • Defendant: Microsoft Corporation (Washington)
  • Plaintiff’s Counsel: Goodwin Procter LLP
• Case Identification: 8:23-cv-02415, C.D. Cal., 12/19/2023
• Venue Allegations: Plaintiff alleges venue is proper in the Central District of California because Defendant is subject to personal jurisdiction, transacts business, offers infringing products for sale, and maintains regular and established places of business in the district.
• Core Dispute: Plaintiff alleges that Defendant’s Microsoft Windows operating systems and Microsoft Surface computing devices, which include "Microsoft Search" functionality, infringe three patents related to methods for incremental, "as-you-type" computer searching.
• Technical Context: The technology at issue concerns real-time search systems that update and display results incrementally as a user types characters into a search field, a foundational feature of modern desktop and operating system search interfaces.
• Key Procedural History: The complaint alleges that Defendant had pre-suit knowledge of the asserted patent family since at least December 4, 2008, based on a Microsoft patent application that cited the earliest-issued patent-in-suit. This allegation forms the basis for claims of willful infringement.

Case Timeline

Date	Event
2002-09-03	Earliest Priority Date for ’035, ’139, and ’490 Patents
2008-05-06	’035 Patent Issued
2008-12-04	Microsoft patent application citing ’035 Patent filed
2017-04-25	’139 Patent Issued
2020-02-04	’490 Patent Issued
2023-10-01	’035 Patent Expired
2023-10-01	’139 Patent Expired
2023-12-19	Complaint Filed
2024-11-08	’490 Patent Expires

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 7,370,035 - Methods and Systems for Search Indexing, Issued May 6, 2008

The Invention Explained

• Problem Addressed: The patent’s background describes conventional search applications as "slow and cumbersome," requiring a user to type a full search term, initiate the search, and then review the results, a process described as a "deliberative and tedious strategy" (’035 Patent, col. 1:43-46, 2:4-6; Compl. ¶20).
• The Patented Solution: The invention discloses a method for "incremental or reactive searching" where search results are "provided or narrowed substantially immediately after each character in a search string is entered by a user" (’035 Patent, col. 2:13-16). This provides immediate feedback. The solution specifically addresses multi-term queries by receiving a first and second search string separated by a "string separator character" and displaying only the documents that contain words beginning with both strings (’035 Patent, col. 2:23-31; Compl. ¶22).
• Technical Importance: This "as-you-type" search functionality represented a significant improvement in user interface efficiency and search speed compared to the traditional "type-click-wait" search model (Compl. ¶21).

Key Claims at a Glance

• The complaint asserts independent claim 10 (Compl. ¶42).
• The essential elements of claim 10 include:
  • A method of performing a search, comprising:
  • receiving a first search string in a first search field;
  • in response, incrementally locating a first group of documents having a word that begins with the first search string;
  • receiving a second search string in the same search field, separated from the first by a string separator character;
  • in response, incrementally locating a second group of documents having a word that begins with the second search string; and
  • displaying an indication of documents included in both the first and second groups.
• The complaint reserves the right to assert dependent claims (Compl. ¶19).

U.S. Patent No. 9,633,139 - Methods and Systems for Search Indexing, Issued April 25, 2017

The Invention Explained

• Problem Addressed: The ’139 Patent addresses the same problems as its parent '035 Patent: the slow and inefficient nature of conventional search engines that require users to execute discrete search commands and review static result lists (’139 Patent, col. 1:38-45; Compl. ¶28).
• The Patented Solution: The invention builds on the incremental, multi-string search method by adding a specific refinement: the system identifies documents where "the first partial search string and the second partial search string are non-adjacent in at least one of the identified documents" (’139 Patent, col. 2:46-52). This allows the system to find documents where the search terms appear separately, not just contiguously, while still updating results incrementally as the user types (’139 Patent, Abstract; Compl. ¶30).
• Technical Importance: This approach improves search relevance by identifying documents where key terms are conceptually related but not necessarily located next to each other, a limitation of simpler search algorithms (Compl. ¶31-32).

Key Claims at a Glance

• The complaint asserts independent claim 23 (Compl. ¶52).
• The essential elements of claim 23 include:
  • A method of performing a search, comprising:
  • receiving first and second partial search strings in a search field, separated by a string separator character;
  • incrementally searching for a first group of documents corresponding to the first string and a second group corresponding to the second string; and
  • updating search results as each successive character of the strings is received by identifying documents included in both groups, "wherein the first partial search string and the second partial search string are non-adjacent in at least one of the identified documents."
• The complaint reserves the right to assert dependent claims (Compl. ¶19).

U.S. Patent No. 10,552,490 - Methods and Systems for Search Indexing, Issued February 4, 2020 (Multi-Patent Capsule)

• Technology Synopsis: The ’490 Patent describes a computing system designed to solve the problem of slow conventional searching by using an "index data structure comprising associations between files and character strings" (’490 Patent, col. 2:20-24, 5:29-32; Compl. ¶37). The system performs an incremental, multi-string search against this index, updating results as a user types and identifying files where the search strings are non-adjacent, thereby improving search speed and accuracy (Compl. ¶38, ¶14).
• Asserted Claims: The complaint asserts independent claim 1 (Compl. ¶62).
• Accused Features: The complaint accuses Microsoft's search functionality, which uses an index to store and retrieve data, of infringing the claimed system (Compl. ¶62).

III. The Accused Instrumentality

Product Identification

The complaint identifies two categories of accused instrumentalities: "Accused Laptop Products" (Microsoft Surface Laptop Go 3, Surface Laptop Go 2, Surface Laptop 5, Surface Laptop Studio, and Surface Laptop Studio 2) and "Accused Windows Products" (Microsoft Windows 10, Windows 11, and Windows 365) (Compl. ¶16). The allegedly infringing software component within these products is identified as "Microsoft Search" (Compl. ¶3, ¶42).

Functionality and Market Context

The Accused Products are computer hardware and operating systems that provide users with file and information search capabilities through the Microsoft Search software (Compl. ¶16, ¶42). The complaint alleges that this search functionality, which provides real-time results as a user types, is central to the user experience of the Windows operating system and Surface devices (Compl. ¶3, ¶4). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint references claim chart exhibits that were not provided. The infringement theories are therefore summarized in prose based on the complaint’s narrative allegations.

'035 Patent Infringement Allegations

The complaint alleges that the Microsoft Search feature infringes at least claim 10 of the ’035 Patent (Compl. ¶42). The narrative infringement theory suggests that when a user enters two or more words separated by a space into a Microsoft Search field, the system performs the claimed method. It is alleged that the system incrementally locates a first set of documents matching the first word, incrementally locates a second set matching the second word, and displays results that are common to both sets, mirroring the steps of claim 10 (Compl. ¶22, ¶42).

'139 Patent Infringement Allegations

The infringement allegation for the ’139 Patent centers on claim 23 and is an extension of the theory for the ’035 Patent (Compl. ¶52). The complaint alleges that Microsoft Search not only performs an incremental, multi-string search but also identifies and displays documents where the entered search terms are "non-adjacent" (Compl. ¶30). This alleges that the accused search functionality can find a document where, for example, a first search term appears in the title and a second search term appears later in the body text (Compl. ¶31).

Identified Points of Contention

• Scope Questions: Does the term "string separator character" as used in the patents read on a common space character used to separate words in a typical search query? The patents describe treating punctuation marks as separators, which may raise the question of whether the claims were intended to cover standard multi-word searches or only those using more specific, designated separators (’139 Patent, col. 2:61-64).
• Technical Questions: What evidence demonstrates that Microsoft Search performs the claimed multi-step process of first "incrementally locating" a group for the first string and then separately "incrementally locating" a group for the second string? An alternative technical approach could involve a single incremental search operation for the composite query, which may not align with the claim language.

V. Key Claim Terms for Construction

The Term: "incrementally locating" / "incrementally searching"

• Context and Importance: This is the central concept of the asserted claims. Its construction will determine the required timing and frequency of search updates. Practitioners may focus on this term because the difference between updating after every single keystroke versus updating after a brief pause in typing could be dispositive for infringement.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification describes providing the user with "substantially immediate feedback as the search string is being entered" to allow the user to "quickly decide" whether to modify the string, which may support a construction focused on the user's perception of real-time feedback rather than a rigid technical requirement (’035 Patent, col. 2:16-21).
  • Evidence for a Narrower Interpretation: The same passage states that results are provided "substantially immediately after each character in a search string is entered," which could support a narrower construction requiring a distinct search or filtering operation upon every individual character input (’035 Patent, col. 2:13-16).

The Term: "non-adjacent"

• Context and Importance: This term is a key limitation in claim 23 of the ’139 Patent. The infringement analysis for this patent will depend on whether Microsoft Search is found to perform a search for terms that are not next to each other in a manner covered by this term.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The claim language itself, "wherein the first partial search string and the second partial search string are non-adjacent in at least one of the identified documents," does not specify a degree of separation, which could support a broad interpretation covering any result where the terms are not contiguous (’139 Patent, col. 11:62-64).
  • Evidence for a Narrower Interpretation: The patent does not appear to provide an explicit definition for "non-adjacent." A defendant may argue that, in the context of the invention, the term requires a specific technical mechanism beyond a standard Boolean "AND" search, which also returns results where terms are not contiguous.

VI. Other Allegations

• Indirect Infringement: The complaint alleges both inducement and contributory infringement (Compl. ¶46, ¶56). Inducement is alleged based on Microsoft providing "installation/technical manuals, troubleshooting guides, and/or product tutorials" that instruct end-users on how to use the allegedly infringing search methods (Compl. ¶47, ¶57). Contributory infringement is alleged based on Microsoft providing the Accused Products with the Microsoft Search software, which is a component that allegedly contributes to the direct infringement by end-users (Compl. ¶48, ¶58).
• Willful Infringement: Willfulness is predicated on alleged pre-suit and post-suit knowledge. The complaint alleges Microsoft has known of the patent family since at least December 4, 2008, the filing date of a Microsoft patent application that cited the ’035 Patent (Compl. ¶44, ¶54, ¶64). Knowledge is also alleged from the date of the complaint's filing (Compl. ¶44).

VII. Analyst’s Conclusion: Key Questions for the Case

• A core issue will be one of definitional scope: can the claimed term "string separator character," which the patents associate with punctuation, be construed to cover the common space character used in virtually all multi-word searches? The answer could significantly impact the breadth of the claims.
• A key question of claim construction will be the meaning of "incrementally." Must the accused system perform a new search operation upon every single keystroke to infringe, or is it sufficient to provide a user experience of real-time updates, such as by searching after a brief pause in typing?
• A central evidentiary question will be one of technical operation: does Microsoft Search perform the specific, multi-step process of locating a first group of documents for a first string and a second group for a second string before displaying their intersection, as the claims require, or does it achieve a similar result through a different, non-infringing technical method?