DCT
8:23-cv-00096
Huang v. Meta Platforms Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Xiaohua Huang (California), Pro Se
- Defendant: Meta Platforms, Inc. (California); Best Buy Co., Inc. (Minnesota); Walmart, Inc. (Arkansas); Amazon.com, Inc. (Washington)
- Plaintiff’s Counsel: Pro Se
- Case Identification: 8:23-cv-00096, M.D. Fla., 06/07/2023
- Venue Allegations: Plaintiff alleges venue is proper based on Defendants' sales of accused products through retail stores and facilities in the district, and the residence and employment of Meta engineers and researchers in Orlando, Florida.
- Core Dispute: Plaintiff alleges that virtual reality headsets sold by Meta and re-sold by other defendants, as well as networking routers and cell phones sold by Amazon, Walmart, and Best Buy, infringe three patents related to high-speed, low-power semiconductor memory circuits.
- Technical Context: The patents relate to the design of Content Addressable Memory (CAM) cells and priority encoding logic, foundational technologies for enabling rapid data searching and processing in high-performance integrated circuits used in networking equipment, processors, and other advanced electronics.
- Key Procedural History: The complaint states that two of the patents-in-suit (U.S. Patent Nos. 6,744,653 and 6,999,331) expired in July 2022. It also references a prior lawsuit filed by the Plaintiff against Amazon in 2019 (Case 3:19-cv-5853) asserting these same two patents, which may limit the scope of recoverable damages to the pre-expiration period.
Case Timeline
| Date | Event |
|---|---|
| 2001-10-04 | Priority Date for ’653 and ’331 Patents |
| 2004-03-04 | Priority Date for RE45,259 Patent |
| 2004-06-01 | ’653 Patent Issued |
| 2006-02-14 | ’331 Patent Issued |
| 2014-11-25 | RE45,259 Patent Issued |
| 2019 | Plaintiff filed complaint against Amazon (3:19-cv-5853) |
| 2022-07 | ’653 and ’331 Patents Expired |
| 2023-06-07 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Reissued Patent No. RE45,259 - Hit Ahead Hierarchical Scalable Priority Encoding Logic and Circuits
- Patent Identification: RE45,259, "Hit Ahead Hierarchical Scalable Priority Encoding Logic and Circuits," issued November 25, 2014.
The Invention Explained
- Problem Addressed: In content addressable memory (CAM), multiple entries may match a search query simultaneously (a "multi-hit"). The system must then select the single highest-priority address from these hits. Conventional logic for this "priority encoding" can be slow, especially as the number of entries in the memory grows, creating a performance bottleneck. (RE45,259 Patent, col. 1:26-48).
- The Patented Solution: The invention discloses a "Hit Ahead Priority Encoding" (HAPE) architecture. This system uses a multi-level, hierarchical structure where a "hit signal" is generated first in each logic block to quickly inform the next level's priority encoding process. This allows priority to be determined in parallel across different levels, aiming to improve speed and make the circuit design more flexible and scalable for very large memories. (RE45,259 Patent, Abstract; col. 2:7-14).
- Technical Importance: The described technique aims to accelerate a critical function in high-performance CAMs, which are essential components in applications like network routers that require extremely fast data lookups. (RE45,259 Patent, col. 1:15-19).
Key Claims at a Glance
- The complaint asserts at least independent claim 29 (Compl. ¶12).
- Essential elements of claim 29 include:
- A content addressable memory (CAM) system, comprising:
- one or more columns comprising a plurality of circuit segments;
- at least one of the circuit segments configured to generate a first circuit segment output based on whether at least one of a plurality of circuit segment inputs received by the at least one of the circuit segments corresponds to a first logic level;
- at least one of the one or more columns configured to generate first address information based on a selected one of the first circuit segment outputs that corresponds to a second logic level, to set a node to a third logic level in response to a first input signal, and to subsequently change the node to a fourth logic level in response to one or more of a plurality of second input signals.
- The complaint does not explicitly reserve the right to assert dependent claims.
U.S. Patent No. 6,744,653 - CAM Cells and Differential Sense Circuits for Content Addressable Memory (CAM)
- Patent Identification: 6,744,653, "CAM Cells and Differential Sense Circuits for Content Addressable Memory (CAM)," issued June 1, 2004.
The Invention Explained
- Problem Addressed: The patent describes conventional CAMs as being potentially slow and power-intensive. A "wired-OR" design requires a single mismatched bit's transistor to discharge the entire row's "match line," a slow process for large rows. Further, discharging the match lines for all non-matching rows consumes significant power. (’653 Patent, col. 1:53–col. 2:11).
- The Patented Solution: The invention proposes a CAM cell design that includes not only a standard "output transistor" coupled to a "match line," but also a "dummy transistor" coupled to a separate "dummy line." This structure enables a differential sense circuit to rapidly detect a small voltage difference between the match line and the dummy line to determine a match/mismatch, rather than waiting for the match line to be fully discharged. This is intended to increase speed and reduce power consumption. (’653 Patent, Abstract; col. 2:24-38).
- Technical Importance: By enabling faster, low-voltage-swing sensing, this design addresses key performance limitations in CAMs, making them more suitable for high-speed, power-sensitive applications. (’653 Patent, col. 2:18-23).
Key Claims at a Glance
- The complaint asserts at least independent claim 1 (Compl. ¶17).
- Essential elements of claim 1 include:
- A content addressable memory (CAM) cell comprising:
- a memory cell operable to store a bit value; and
- a comparison circuit coupled to the memory cell and configured to detect the bit value stored in the memory cell, the comparison circuit including
- an output transistor coupled to a match line and configured to provide a drive for the match line based on the detected bit value, and
- a dummy transistor coupled to a dummy line and configured to provide a drive for the dummy line based on an inverted detected bit value, wherein the match line and dummy line are used to detect output values provided by other CAM cells also coupled to the match and dummy lines.
- The complaint does not explicitly reserve the right to assert dependent claims.
Multi-Patent Capsule: U.S. Patent No. 6,999,331 - CAM Cells and Differential Sense Circuits for Content Addressable Memory (CAM)
- Patent Identification: 6,999,331, "CAM Cells and Differential Sense Circuits for Content Addressable Memory (CAM)," issued February 14, 2006.
- Technology Synopsis: As a continuation of the ’653 Patent, this patent addresses the same technical challenges of speed and power consumption in conventional CAMs. It likewise discloses the use of dummy CAM cells and differential sensing circuits to enable faster and more power-efficient detection of match/mismatch states. (’331 Patent, col. 1:5-11, col. 2:18-24).
- Asserted Claims: The complaint asserts at least independent claim 1 (Compl. ¶22).
- Accused Features: The complaint alleges that "Networking Routers, cell phones including but not limited to Cisco ASR1000 Series Aggregation Services Routers and Pixel 5 etc." contain a "circuit and logic function which have infringed at least claim 1." (Compl. ¶22).
III. The Accused Instrumentality
Product Identification
- The complaint names several categories of accused products:
- Virtual and augmented reality hardware, "including but not limited to Meta Quest Pro, Oculus Quest 2 etc.," are accused of infringing the ’RE259 Patent (Compl. ¶¶7, 12).
- Networking routers, "including but not limited to Cisco ASR1000 Series Aggregation Services Routers," are accused of infringing the ’653 and ’331 Patents (Compl. ¶¶17, 22).
- Cell phones, "such as google cell phone" and "including but not limited Pixel5, Pixel6 etc.," are accused of infringing the ’653 and ’331 Patents (Compl. ¶¶9, 17, 22).
Functionality and Market Context
- The complaint offers minimal detail on the technical operation of the accused products. It alleges that the Meta VR products contain an "IC with the function which read the claim 29" of the ’RE259 Patent, and that customers use the "function of image sensor and Digital to Analog convertor" (Compl. ¶¶7, 13). For the routers and cell phones, it alleges that they contain infringing circuitry used for a "networking security function ACL" (Access Control List) (Compl. ¶¶18, 23). The complaint does not provide further technical specifics on how these alleged functions map to the patent claims.
No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
The complaint does not provide claim charts or a detailed, element-by-element breakdown of its infringement theories. The analysis below is based on the complaint's more general allegations.
RE45,259 Patent Infringement Allegations
| Claim Element (from Independent Claim 29) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A content addressable memory (CAM) system, comprising: one or more columns comprising a plurality of circuit segments | The "circuit and logic design found in the IP block of the chip used in VR system of Meta Platforms, Inc." (Compl. ¶6). | ¶6 | col. 14:1-12 |
| at least one of the circuit segments configured to generate a first circuit segment output based on whether at least one of a plurality of circuit segment inputs...corresponds to a first logic level | The "circuit and logic function" within the accused VR hardware (Compl. ¶12). The complaint does not specify the functionality further. | ¶12 | col. 14:13-19 |
| at least one of the one or more columns configured to generate first address information based on a selected one of the first circuit segment outputs...to set a node to a third logic level...and to subsequently change the node to a fourth logic level... | The "circuit and logic function" within the accused VR hardware (Compl. ¶12), and the "function of image sensor and Digital to Analog convertor" (Compl. ¶13). | ¶¶12, 13 | col. 14:20-30 |
’653 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A content addressable memory (CAM) cell comprising: a memory cell operable to store a bit value; and a comparison circuit... | The "circuit and logic function" contained within accused networking routers and cell phones (Compl. ¶¶17, 18). | ¶¶17, 18 | col. 18:14-18 |
| an output transistor coupled to a match line and configured to provide a drive for the match line based on the detected bit value | The "circuit and logic function" associated with the "networking security function ACL" (Compl. ¶18). | ¶18 | col. 18:20-23 |
| a dummy transistor coupled to a dummy line and configured to provide a drive for the dummy line based on an inverted detected bit value... | The "circuit and logic function" associated with the "networking security function ACL" (Compl. ¶18). | ¶18 | col. 18:24-29 |
- Identified Points of Contention:
- Factual Specificity: A primary issue will be whether the complaint's allegations provide sufficient factual detail to be plausible. The complaint asserts that the accused products contain infringing "circuit and logic" and "functions" but does not specify what those circuits are or how they operate in a manner that meets the specific limitations of the asserted claims.
- Technical Questions: What evidence does the complaint provide that the accused products, which serve broad functions like virtual reality and network security, contain the specific "dummy transistor" and "differential sense" architecture required by claim 1 of the ’653 patent? Similarly, what is the factual basis for alleging that the accused VR headsets implement the multi-level "hit ahead" priority encoding structure of claim 29 of the ’RE259 patent?
V. Key Claim Terms for Construction
The Term: "dummy transistor coupled to a dummy line" (from claim 1 of the ’653 Patent)
Context and Importance: This phrase captures the core of the asserted invention in the ’653 patent. The infringement analysis will depend on whether any circuit within the accused routers and phones can be characterized as a "dummy transistor" and "dummy line" used for differential sensing. Practitioners may focus on whether this requires a dedicated, structurally similar replica circuit or if any form of reference signal generation qualifies.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: Claim 1 describes the dummy transistor's function as providing a drive "based on an inverted detected bit value," which could suggest a functional rather than purely structural definition. (’653 Patent, col. 18:24-27).
- Evidence for a Narrower Interpretation: The specification repeatedly describes and depicts the dummy transistor as having a "physical dimension that is the same as output transistor 240" or a specific fraction thereof, and being "located near output transistor 240." This language, along with figures like FIG. 2E, suggests a specific, physically proximate, and dimensionally related circuit element, not just any reference generator. (’653 Patent, col. 5:61-64; Fig. 2E).
The Term: "circuit segment" (from claim 29 of the ’RE259 Patent)
Context and Importance: The definition of "circuit segment" is fundamental to the hierarchical structure claimed in the ’RE259 patent. The dispute will likely center on what level of granularity this term implies and whether functional blocks within the accused VR chips meet the definition.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language is abstract, referring to a "plurality of circuit segments" within "one or more columns," which could be argued to cover various logical or physical partitions within a larger circuit. (’RE259 Patent, col. 14:13-14).
- Evidence for a Narrower Interpretation: The detailed description and figures illustrate "circuit segments" as specific hardware blocks performing priority encoding and hit generation (e.g., blocks 201, 202, 203 in FIG. 2a). This may support an interpretation requiring a specific hardware implementation rather than a more abstract functional grouping. (’RE259 Patent, Fig. 2a; col. 3:20-41).
VI. Other Allegations
- Indirect Infringement: The complaint alleges inducement of infringement for all three patents. It asserts that Defendants' customers infringe by using the accused devices, such as by using the "function of image sensor and Digital to Analog convertor" in the VR headsets or the "networking security function ACL" in routers and phones (Compl. ¶¶13, 18, 23). The complaint does not allege specific facts regarding Defendants' intent, such as citations to user manuals or marketing materials that instruct users on the infringing use.
- Willful Infringement: The complaint does not explicitly plead "willful infringement," but it does seek enhanced damages and attorney fees under 35 U.S.C. §§ 284 and 285 (Compl. ¶¶14, 19, 24). The complaint alleges that for the Google cell phones sold by Best Buy and Walmart, "both seller and the manufacture were informed in the year of 2021" about the infringement (Compl. ¶9). This allegation of pre-suit knowledge may be used to support a claim for enhanced damages against those defendants for those specific products.
VII. Analyst’s Conclusion: Key Questions for the Case
- A primary issue will be one of pleading sufficiency: will the court find the complaint's generalized allegations that the accused products contain infringing "circuit and logic" sufficient to state a plausible claim for relief under the Twombly/Iqbal standard, or will it require more specific factual allegations detailing how the accused products practice the claimed inventions?
- A key evidentiary question will be one of technical mapping: assuming the case proceeds, can the plaintiff demonstrate that the complex integrated circuits within commercial products like the Meta Quest or Pixel phones incorporate the specific, low-level circuit architectures claimed in the patents, such as the "dummy transistor" for differential sensing or the "hit ahead" hierarchical logic?
- A central question for damages will be the impact of patent expiration: for the ’653 and ’331 patents, which expired in July 2022, the dispute will focus on establishing the existence and quantum of damages accrued only during the pre-expiration period of alleged infringement.