DCT

4:09-cv-01315

Yufa v. TSI Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 4:09-cv-01315, N.D. Cal., 09/18/2012
  • Venue Allegations: Venue is alleged based on Defendant conducting business, including sales, through a branch office within the Northern District of California.
  • Core Dispute: Plaintiff alleges that Defendant’s particle counting and monitoring systems infringe a patent related to methods and apparatus for wirelessly communicating particle measurements using digital signal processing.
  • Technical Context: The technology involves high-sensitivity particle counters used for contamination control in environments like semiconductor fabrication and pharmaceutical manufacturing, where air and liquid purity are critical.
  • Key Procedural History: This First Amended Complaint was filed following a court order. The patent-in-suit, U.S. Patent No. 6,346,983, was the subject of an Ex Parte Reexamination which concluded on August 14, 2012. The reexamination resulted in the cancellation of original claims 1-5 and the amendment of claims 6-8, which are the claims now asserted in this action. This reexamination history will likely be central to interpreting the scope of the asserted claims.

I.A. Case Timeline

Date Event
1998-01-29 ’983 Patent Priority Date
2002-02-12 ’983 Patent Original Issue Date
2002-06-01 Publication describing ’983 Patent in "CleanRooms" magazine
2008-10-01 TSI Incorporated acquires "Adams Instruments"
2012-08-14 ’983 Patent Reexamination Certificate (US 6,346,983 C1) Issued
2012-09-18 First Amended Complaint Filing Date

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

  • Patent Identification: U.S. Patent No. 6,346,983, titled "Method and Wireless Communicating Particle Counting and Measuring Apparatus," issued February 12, 2002. The claims-at-issue were amended by Ex Parte Reexamination Certificate US 6,346,983 C1, issued August 14, 2012.

II.A. U.S. Patent No. 6,346,983 - "Method and Wireless Communicating Particle Counting and Measuring Apparatus"

II.A.1. The Invention Explained

  • Problem Addressed: The patent describes prior art particle counters as suffering from two key deficiencies: 1) reliance on wired connections between sensors and processing units, which limits mobility and introduces electromagnetic noise, and 2) use of analog comparison methods to measure particle size, which limits sensitivity and accuracy (’983 Patent, col. 3:21-39).
  • The Patented Solution: The invention discloses an apparatus with a remote sensor that communicates wirelessly with a central data processing system (’983 Patent, Abstract). Critically, instead of comparing analog signal amplitudes to a reference voltage, the patented method converts a detected analog signal into a digital pulse whose duration corresponds to the particle's size. It then measures this duration by counting the number of high-frequency "strobe pulses" that fit within the main pulse, a digital technique intended to increase precision (’983 Patent, col. 10:15-30).
  • Technical Importance: This approach sought to provide more flexible and sensitive particle monitoring for "clean room" environments, which are essential for manufacturing advanced semiconductors and other contamination-sensitive products (’983 Patent, col. 3:6-14).

II.A.2. Key Claims at a Glance

  • The complaint asserts infringement of claims 6, 7, and 8, with claim 6 being the sole independent claim asserted (Compl. ¶10).
  • The essential elements of the amended independent claim 6 are:
    • a current-voltage conversion means
    • an amplifying means
    • an analog-digital form pulse duration conversion means, providing conversion of voltage signals to a digital form pulse without using a reference voltage to convert each signal
    • a strobe pulse generating means
    • a conjunction means, for forming strobe pulse packages
    • a selecting, sorting and counting means for processing the strobe pulse packages
  • The complaint asserts dependent claims 7 and 8, which add further limitations to the system's connections (’983 C1 Patent, col. 2:20-32).

III. The Accused Instrumentality

III.A. Product Identification

  • The complaint accuses a wide range of TSI products, including the "R-Series" remote models; AEROTRAK Handheld, Portable, and Remote Particle Counters (e.g., models 9303, 9306, 9310, 9500, 7110); the BIOTRAK Real-Time Viable Particle Counter; and the overarching "Facility Monitoring System" (Compl. ¶16, ¶18).

III.B. Functionality and Market Context

  • The accused products are described as particle counters and monitoring systems used for contamination control (Compl. ¶16). The complaint's central technical allegation is that Defendant’s "Facility Monitoring System" utilizes devices that provide "Pulse Width Modulation (PWM) which '... encod[es] an analogue value as a digital pulse where the on time is proportional to the value. ...'" (Compl. ¶18). This PWM functionality is the primary feature alleged to practice the core of the patented method. The complaint provides a screenshot of a webpage from the Defendant, described as Exhibit J, to support its allegations regarding the accused "TSI AEROTRAKTM Remote 4-20 mA Sensors Life Science" products (Compl. ¶18).

IV. Analysis of Infringement Allegations

The complaint references a "Claim comparison chart" in Exhibit G, which was not provided with the pleading (Compl. ¶17). The following table synthesizes the infringement allegations from the complaint's narrative.

'983 Patent Infringement Allegations

Claim Element (from Independent Claim 6) Alleged Infringing Functionality Complaint Citation Patent Citation
an analog-digital form pulse duration conversion means, providing conversion of each of said voltage value signals to a digital form pulse without using a reference voltage... Defendant's systems allegedly use "Pulse Width Modulation (PWM)" which "encod[es] an analogue value as a digital pulse where the on time is proportional to the value." ¶18 col. 1:19-23 (Reexam)
a selecting, sorting and counting means, providing the selection and sorting of said strobe pulse packages... The accused products are identified as "Particle Counters," which are used to count and measure particles. The complaint alleges these products provide "non-analog processing of the detected signals." ¶11, ¶16, ¶31 col. 2:13-19 (Reexam)
Other elements of Claim 6 (e.g., current-voltage conversion, amplifying, strobe pulse generation, conjunction means) The complaint does not provide specific detail for analysis of these elements, instead alleging generally that the products operate and are structured in compliance with the claims. ¶16, ¶30 col. 1:24 - col. 2:12 (Reexam)
  • Identified Points of Contention:
    • Scope Questions: A primary dispute may concern the meaning of "without using a reference voltage," a phrase added during reexamination. The question for the court will be whether the accused PWM systems, which may use reference voltages for timing or other functions, fall within the scope of this limitation.
    • Technical Questions: The complaint's allegations focus on PWM as the infringing conversion step but provide no specific facts on how the accused products perform the subsequent, required steps of using a "strobe pulse generating means" and a "conjunction means" to create and count "strobe pulse packages". A key question is whether the accused systems perform these specific functions or use a different digital counting technique.

V. Key Claim Terms for Construction

  • The Term: "without using a reference voltage"
  • Context and Importance: This limitation was added to independent claim 6 during reexamination and was likely critical to overcoming prior art rejections. Its construction will be central to the infringement analysis. Practitioners may focus on this term because it appears to be the primary patentability distinction and, therefore, a key non-infringement argument.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: A party could argue the phrase should be interpreted in the context of the problem solved by the patent—avoiding the specific analog amplitude comparison shown in the prior art, where a signal's voltage level is directly compared to a series of reference voltages to "bin" the particle size (’983 Patent, col. 2:20-29, Fig. 1).
    • Evidence for a Narrower Interpretation: A party could argue the plain language requires the absolute absence of any reference voltage in the conversion process. The reexamined claim contrasts with the original specification, which does not heavily emphasize this feature, potentially suggesting the term was a sharp disclaimer made during prosecution to secure the patent.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges inducement based on Defendant’s technical and marketing documents, such as "Introduction To Interfaces Used In Facility Monitoring Systems" and "Facility Monitoring System Design Recommendations," which allegedly instruct customers on how to use the accused systems in an infringing manner (Compl. ¶18).
  • Willful Infringement: The willfulness claim is based on alleged pre-suit knowledge. The complaint alleges that Plaintiff had telephonic and written communications with Defendant’s representatives regarding the patent and the alleged infringement prior to the lawsuit (Compl. ¶¶ 11-13). It further alleges that Defendant had knowledge from a June 2002 article describing the patent in "CleanRooms" magazine, an industry publication (Compl. ¶25, ¶26).

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

  • A core issue will be one of claim construction: how narrowly will the court construe the limitation "without using a reference voltage," which was added during reexamination? The viability of the infringement claim may depend on whether this phrase is interpreted to only forbid prior art analog amplitude comparisons or if it precludes any use of a reference voltage in the accused devices' signal processing circuits.
  • A key evidentiary question will be one of technical proof: can the Plaintiff provide evidence that the accused PWM-based systems perform the specific, multi-step process recited in claim 6, particularly the generation and counting of "strobe pulse packages"? The complaint's allegations are more detailed regarding the initial signal conversion than the subsequent digital processing steps.
  • The case also presents a question of willfulness based on notice: will the Plaintiff's alleged pre-suit communications as a pro-se inventor and a publication in an industry trade magazine be sufficient to establish the knowledge and intent required for a finding of willful infringement?