DCT
8:19-cv-00955
Uniloc 2017 LLC v. Microsoft Corp
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Uniloc 2017 LLC (Delaware)
- Defendant: Microsoft Corporation (Washington)
- Plaintiff’s Counsel: Feinberg Day Alberti Lim & Belloli LLP
- Case Identification: 8:19-cv-00955, C.D. Cal., 05/20/2019
- Venue Allegations: Venue is alleged to be proper based on Defendant's commission of infringing acts and its regular and established places of business within the Central District of California.
- Core Dispute: Plaintiff alleges that Defendant’s Microsoft Surface Go products, which incorporate USB-C ports, infringe a patent related to detecting the connection of devices on a communication bus using wave reflection principles.
- Technical Context: The technology at issue involves methods for detecting the presence of connected peripherals on high-speed data buses, a fundamental function for modern interfaces like USB that are ubiquitous in consumer and enterprise electronics.
- Key Procedural History: Subsequent to the filing of this complaint, the sole independent claim asserted, Claim 1 of the ’541 patent, was challenged in an inter partes review. The Patent Trial and Appeal Board instituted the IPR and ultimately found the claim unpatentable. A certificate cancelling Claim 1 was issued on October 15, 2021 (IPR2020-00102). This cancellation is dispositive of the infringement allegations as originally pleaded in the complaint.
Case Timeline
| Date | Event |
|---|---|
| 2000-06-20 | ’541 Patent Priority Date |
| 2002-12-24 | ’541 Patent Issue Date |
| 2019-05-20 | Complaint Filing Date |
| 2019-05-20 | Date of Uniloc's notice letter to Microsoft |
| 2021-10-15 | IPR Certificate issued cancelling Asserted Claim 1 |
II. Technology and Patent(s)-in-Suit Analysis
- Patent Identification: U.S. Patent No. 6,498,541, "Communication Bus System And Apparatus And Device For Use In Such A System," issued December 24, 2002.
The Invention Explained
- Problem Addressed: The patent describes conventional methods for detecting device connection and disconnection on a bus system (like USB) as potentially causing "a delay in disconnection and reduced transmission capacity" because they may require a dedicated "period of 'silence'" on the bus ('541 Patent, col. 2:51-56). The goal is to reduce the time needed for this detection ('541 Patent, col. 2:61-63).
- The Patented Solution: The invention proposes using wave reflection to detect the presence of a connected device. A station transmits a "wave signal" down the transmission line and employs a "wave splitter" to separate the outgoing wave from any "returning wave" that is reflected back from the connector end ('541 Patent, col. 2:16-24; Fig. 2). If a properly terminated device is connected, the impedance matches the line and there is substantially no reflection; if no device is connected (an open circuit), a reflection occurs. A control unit then operates the system differently based on whether a reflection is detected, thereby determining the connection status ('541 Patent, Abstract).
- Technical Importance: The proposed solution offers a method to determine connection status that could, in principle, operate in real-time without interrupting data flow on the bus, thus improving overall system efficiency and responsiveness ('541 Patent, col. 2:61-63).
Key Claims at a Glance
- The complaint asserts independent claim 1 ('Compl. ¶9).
- The essential elements of Claim 1 are:
- A method of controlling a bus communication system, wherein the connection of a station to the bus system via a connector is detected by:
- transmitting a transmitted wave signal via the connector
- and splitting of a return wave received at the connector,
- the bus system being operated in accordance with presence or absence of the further station
- dependent on non-detection and detection of a reflection of the transmitted wave signal respectively.
- The complaint does not explicitly reserve the right to assert dependent claims.
III. The Accused Instrumentality
Product Identification
- The complaint names the "Microsoft Surface Go" as an exemplary accused device, along with other Microsoft devices that "perform a method of controlling a bus communication system" in a similar manner (collectively the "Accused Infringing Devices") (Compl. ¶6, ¶12).
Functionality and Market Context
- The accused functionality resides in the devices' USB-3.1 (also known as USB-C) interface, which the complaint identifies as a "bus communication system" (Compl. ¶14). The complaint alleges that these devices implement the "Receiver Detection" (or "Rx Detect") protocol of the USB 3.1 standard to determine if a device is connected to the USB-C port (Compl. ¶16). A screenshot from a product teardown identifies a "Parade Technologies PS87430 (likely USB host switch)" chip as a component involved in this functionality (Compl. p. 5). The complaint alleges this Rx Detect process involves sending a signal and detecting changes in voltage/impedance that it characterizes as detecting a reflected wave, which in turn informs the system's link management operations (Compl. ¶17-18).
IV. Analysis of Infringement Allegations
’541 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| transmitting a transmitted wave signal via the connector | The Accused Infringing Devices are alleged to implement the USB 3.1 Rx Detect protocol, which "requires the transmitter to transmit a wave signal via the connector to the receiver." A diagram from the USB specification illustrates this process (Compl. p. 6). | ¶16 | col. 6:1-2 |
| and splitting of a return wave received at the connector, | The complaint alleges that the Accused Infringing Devices "split a return wave," which it defines as "a change in the common voltage mode is reflected back to the transmitter." A USB PHY is said to detect this change at its transmitter. | ¶17 | col. 6:1-3 |
| the bus system being operated in accordance with presence or absence of the further station | The complaint alleges the system operates based on connection status, citing the USB specification that a transmitter detects "far end receiver termination... and inform[s] the link layer so the connect status can be factored into link operation and management." | ¶18 | col. 6:3-5 |
| dependent on non-detection and detection of a reflection of the transmitted wave signal respectively. | Detection is alleged to be based on the rate of voltage change on the line, which differs depending on whether a terminated receiver is present. The complaint frames this impedance-based detection as the "detection of a reflection." | ¶18 | col. 6:5-9 |
- Identified Points of Contention:
- Scope Questions: A primary question for the court would be whether the accused "Rx Detect" protocol, which functions by measuring the RC time constant (rate of voltage change) on a line, falls within the scope of the patent's claim to "splitting of a return wave" and detecting a "reflection." The patent's disclosure suggests a "wave splitter" apparatus (Fig. 2, 24) and "traveling waves" ('541 Patent, col. 2:5), which may suggest a different technical mechanism than the time-domain voltage measurement described in the USB standard.
- Technical Questions: What evidence does the complaint provide that the accused devices perform a "splitting" of a wave? The complaint alleges this (Compl. ¶17), but the cited USB specifications (e.g., Compl. p. 6-8) describe detecting whether a termination impedance is present by measuring a voltage ramp. A key factual dispute would likely concern whether this measurement process is technically equivalent to the "splitting" action described in the patent.
V. Key Claim Terms for Construction
- The Term: "splitting of a return wave"
- Context and Importance: The plaintiff's infringement theory hinges on mapping the accused USB "Rx Detect" protocol to this claimed step. The construction of this phrase is therefore critical; if construed narrowly to require a specific type of signal-separating circuit, the infringement case may be weakened. Practitioners may focus on this term because the accused functionality (measuring a voltage ramp) does not appear to involve a "splitter" in the conventional RF sense.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent states that an upstream station "spits off the returning wave (if any) from the transmitted wave" ('541 Patent, col. 2:22-24). A party could argue that this supports a functional definition, where any method that successfully distinguishes a return signal from a transmitted signal to determine connection status meets the "splitting" limitation.
- Evidence for a Narrower Interpretation: The patent consistently refers to an apparatus, a "wave splitter (24)," that performs this function ('541 Patent, Fig. 2; col. 6:15). An exemplary circuit for this splitter is provided in Figure 3, which operates by subtracting signals ('541 Patent, col. 5:51-54). A party could argue "splitting" should be limited to the types of separating or subtracting circuits disclosed, not the different mechanism of observing a charge time.
VI. Other Allegations
- Indirect Infringement: The complaint alleges induced infringement based on Microsoft providing instructions to users through "training videos, demonstrations, brochures, installation and user guides," and support websites, which allegedly instruct on the use of the infringing USB-C functionality (Compl. ¶20). Contributory infringement is also alleged, on the basis that portions of the accused devices are especially made for infringement and are not staple articles of commerce (Compl. ¶21).
- Willful Infringement: The complaint alleges willfulness based on Microsoft's purported knowledge of the '541 patent from a letter sent by Uniloc on May 20, 2019, the same day the complaint was filed. This allegation appears to be based on alleged post-suit knowledge (Compl. ¶22).
VII. Analyst’s Conclusion: Key Questions for the Case
- A dispositive procedural question, arising after the complaint's filing, is the effect of the cancellation of asserted Claim 1 in IPR2020-00102. As the sole independent claim asserted in the complaint has been invalidated by the USPTO, the infringement allegations as pleaded appear to be rendered moot.
- A core issue, had the claim survived, would be one of definitional scope: can the claim term "splitting of a return wave," which the patent describes in the context of a "wave splitter" circuit, be construed to cover the accused "Rx Detect" protocol, which determines device presence by measuring the rate of voltage change on the line?
- A related evidentiary question would be one of technical mechanism: does the accused system's measurement of an RC time constant constitute the detection of a "reflection" of a "transmitted wave signal" as those terms are understood in the context of the patent's disclosure, or is there a fundamental mismatch in the underlying physical principles of operation?