JG Tech LLC v. Thruvision Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: JG Technologies LLC (Alabama)
  • Defendant: Thruvision Limited (United Kingdom)
  • Plaintiff’s Counsel: KENT & RISLEY LLC
• Case Identification: 2:23-cv-00092, E.D. Tex., 03/07/2023
• Venue Allegations: Venue is alleged to be proper on the basis that the Defendant is a foreign corporation.
• Core Dispute: Plaintiff alleges that Defendant’s passive security screening systems infringe a patent related to the detection of objects by analyzing their attenuation of background electromagnetic radiation.
• Technical Context: The technology concerns a "Negative Radar" approach for detecting objects, including those with low-radar-profiles, by observing the "shadow" they cast in a field of ambient electromagnetic radiation, rather than detecting reflected signals.
• Key Procedural History: The complaint highlights an unusual prosecution history, noting the patent application was subject to a U.S. Air Force-requested secrecy order for approximately eight years. Plaintiff also notes it previously sued the U.S. Government for using the patent-in-suit via Defendant's technology, a case that resulted in a stipulated judgment in Plaintiff's favor and of which Defendant allegedly had notice.

Case Timeline

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

U.S. Patent No. 7,952,511 - “Method and Apparatus for the Detection of Objects Using Electromagnetic Wave Attenuation Patterns”

• Patent Identification: U.S. Patent No. 7,952,511, issued May 31, 2011.

The Invention Explained

• Problem Addressed: The patent describes the limitations of traditional radar, which relies on detecting reflected signals (echoes) and is thus vulnerable to "stealth" technologies designed to absorb or deflect such signals (Compl. ¶¶16-17; ’511 Patent, col. 1:8-13, 1:33-44). It also notes that existing beam-interruption security sensors are limited because they monitor a narrow "line of sight" and require an object to fully block the beam to be detected (Compl. ¶20; ’511 Patent, col. 2:42-45).
• The Patented Solution: The invention proposes a method of "Negative Radar" that detects an object not by its reflection, but by the "shadow" or attenuation it creates in a pre-existing field of electromagnetic radiation (’511 Patent, col. 2:36-41). This method turns an object's absorptive properties into a means of detection. The system can monitor a large volume of space and can use either an active transmitter or passive background sources, such as cosmic microwave background radiation or terrestrial heat emissions, as the illumination source (Compl. ¶21; ’511 Patent, col. 4:8-15).
• Technical Importance: This approach provided a potential countermeasure to military stealth technology, which was a significant area of development and concern at the time of the invention (Compl. ¶18; ’511 Patent, col. 2:1-6).

Key Claims at a Glance

• The complaint asserts infringement of at least independent claim 16 (Compl. ¶42).
• Claim 16 recites a method with the following essential elements:
  • defining expected characteristics of diffuse source electromagnetic background radiation to be received at a receiver;
  • attenuating at least a portion of diffuse source electromagnetic background radiation received at the receiver by a presence of an object; and
  • detecting the attenuation to indicate a presence of the object. (’511 Patent, col. 16:16-24).
• The complaint states that Plaintiff may assert other claims, including dependent claims, at a later stage (Compl. ¶42).

III. The Accused Instrumentality

Product Identification

The complaint identifies the accused instrumentalities as Defendant’s "passive millimeter wave detection and passive terahertz detection equipment" (Compl. ¶37). It refers to these generally as the "Exemplary Defendant Products" and notes they are identified in a chart (Exhibit B) which is incorporated by reference but not attached to the publicly filed complaint (Compl. ¶42).

Functionality and Market Context

The complaint alleges that Defendant’s technology is used for applications such as employee screening at Dallas/Fort Worth International Airport (Compl. ¶4). Its function is described as "passive," suggesting the systems operate by receiving ambient electromagnetic waves in the millimeter and terahertz spectra to detect objects, rather than by actively transmitting a signal (Compl. ¶37). The complaint also alleges that this technology was procured and used by the U.S. Government (Compl. ¶36).

IV. Analysis of Infringement Allegations

The complaint alleges infringement of at least claim 16 of the ’511 Patent but incorporates by reference a claim chart exhibit that was not filed with the public version of the complaint (Compl. ¶¶42, 48). No probative visual evidence provided in complaint. A summary of the infringement theory, based on the complaint's narrative, is as follows:

The complaint alleges that Defendant's passive detection systems meet the limitations of claim 16 (Compl. ¶¶37, 42). The infringement theory appears to be that the accused systems establish a baseline of ambient millimeter and/or terahertz wave radiation in a given area (the "defining expected characteristics" step). When a person or object enters this area, they block or absorb a portion of that ambient radiation (the "attenuating" step). The system then registers this decrease in received radiation to identify the presence of the person or object (the "detecting the attenuation" step).

Identified Points of Contention

• Scope Questions: The complaint alleges infringement by systems used for security screening, whereas the patent's primary examples involve detecting military aircraft (’511 Patent, figs. 1-3, 8-13). A potential issue is whether the patent's claims, interpreted in light of the specification, can be read to cover the field of personnel security screening.
• Technical Questions: What evidence demonstrates that the accused systems operate on the specific principle of detecting attenuation of "background radiation" as claimed, rather than another technical method, such as detecting thermal emissions from a person's body against a cooler background? The complaint does not detail the precise operational mechanism of the accused products (Compl. ¶37).

V. Key Claim Terms for Construction

• The Term: "diffuse source electromagnetic background radiation" (’511 Patent, col. 16:18-19).

  • Context and Importance: This term defines the medium the invention uses for detection and is central to the scope of Claim 16. The dispute may turn on whether the specific radiation detected by Defendant’s passive systems qualifies under this definition. Practitioners may focus on this term because its construction will determine whether the claim is limited to natural ambient sources or can also cover environments with scattered man-made signals.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification suggests "background radiation" can originate from various sources, including "man-made satellites, for example GPS satellites and the Iridium satellite constellation" and "earth (terrestrial) background radiation" (’511 Patent, col. 4:15-18, 4:50-51).
    • Evidence for a Narrower Interpretation: The claim uses the term "background," and the specification repeatedly discusses natural sources like "3 degree K black body radiation" from the sky, suggesting a primary focus on omnipresent, naturally occurring radiation (’511 Patent, col. 4:12-13).

• The Term: "defining expected characteristics" (’511 Patent, col. 16:18).

  • Context and Importance: This is the first active step of the claimed method. Its construction is critical for determining whether the accused systems' baseline calibration process constitutes "defining" as required by the claim.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification discusses a simple goal of detecting "a normal pattern of illumination" or a "background or normal radiation pattern," which could be interpreted as a simple baseline measurement (’511 Patent, col. 3:21-22, 8:11-12).
    • Evidence for a Narrower Interpretation: The patent also discloses more complex techniques, such as using "adaptive background analysis techniques... to differentiate dynamic effects from static effects," which could support a construction requiring a more sophisticated predictive or analytical process (’511 Patent, col. 4:60-62).

VI. Other Allegations

• Indirect Infringement: The complaint alleges induced infringement, asserting that Defendant provides "product literature and website materials" that instruct and encourage customers to use the accused products in an infringing manner (Compl. ¶¶46-47).
• Willful Infringement: The willfulness allegation is based on alleged actual knowledge of the ’511 Patent and its infringement. The complaint alleges two sources of knowledge: (1) notice served on Defendant on July 10, 2020, in a prior lawsuit against the U.S. Government that involved the same patent and Defendant's technology (Compl. ¶43); and (2) a pre-suit notice letter with a claim chart sent by Plaintiff to Defendant dated February 18, 2023 (Compl. ¶44). The complaint alleges that Defendant’s infringement continued despite this knowledge (Compl. ¶49).

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

• A core issue will be one of definitional scope: can the term "diffuse source electromagnetic background radiation", which is described in the patent in contexts like detecting stealth aircraft against cosmic radiation, be construed to cover the ambient millimeter and terahertz waves allegedly used by Defendant's indoor security screening systems?
• A key evidentiary question will be the precise technical operation of the accused Thruvision products. The case will require factual development to determine if these systems function by detecting the attenuation of background radiation as claimed, or if they operate on a different principle not covered by the patent's claims.
• A central question for damages will be willfulness and the impact of prior litigation: what is the legal effect of the prior lawsuit against the U.S. Government, in which Defendant was given notice but declined to participate? The court will need to determine if this history, culminating in a judgment against the government, establishes that Defendant's alleged post-notice infringement was objectively reckless, potentially warranting enhanced damages.