US 11533794

I have successfully searched the USPTO database for US Patent 11,533,794 and have found all the necessary information, including the title, assignee, inventor, filing date, issue date, abstract, and claims. I do not need to perform another search for this information. I will now proceed to analyze the independent claims and then synthesize the complete summary as requested. I have not yet searched the CAFC dockets, so I will do that in the next step.

U.S. Patent 11,533,794: Resistive bypass for series lighting circuit

A technical analysis of U.S. Patent 11,533,794, titled "Resistive bypass for series lighting circuit," reveals a system designed to improve the reliability of series-connected lighting, such as decorative light strings.

Key Patent Details:

• Assignee: Seasonal Specialties, LLC
• Inventor: Steven J. Altamura
• Filing Date: August 12, 2021
• Issue Date: December 20, 2022
• Abstract: The patent describes a resistor bypass circuit for a series lighting circuit. This circuit includes multiple serially connected LED light sources. A bypass resistor is connected in parallel with at least one of these light sources. A key feature is that the bypass resistor is always in the circuit and conducts current whenever the circuit is active, regardless of whether the LED light source it is paired with is functioning. This ensures that a failure of one light source does not break the entire series circuit.

Plain-Language Summary of Independent Claims:

A patent's claims define the legal scope of the invention. Independent claims are the broadest claims and represent the core of the patented technology.

• Independent Claim 1: This claim outlines a lighting circuit that uses a series of connected LED lights. The key innovation is a bypass resistor placed in parallel with at least one of these LEDs. This resistor is always active, allowing electricity to flow through it even when the LED is working. This design prevents the entire string of lights from going out if a single LED fails.

• Independent Claim 9: This claim describes a similar series-connected LED lighting circuit with a bypass resistor that is always conducting. A key addition in this claim is the inclusion of a specific "LED flashing light source" which contains a flashing circuit. This special flasher is designed to make the entire string of lights flash on and off.

• Independent Claim 10: This claim also details a series-connected LED light circuit with an always-active bypass resistor. The specific a key detail here is that the bypass resistor's resistance must be equal to or greater than the inherent resistance of the LED it is bypassing.

• Independent Claim 15: This claim outlines a method for bypassing an LED light source in a series-connected string. The method involves several steps:

  1. Choosing a bypass resistor with specific qualities.
  2. The resistor's resistance must be equal to or greater than the LED's resistance.
  3. The resistor must be able to handle the full current of the light string.
  4. The resistor must be capable of continuous operation (100% duty cycle).
  5. The final step is to install this chosen resistor in parallel with at least one of the LEDs in the string.

CAFC Docket Search:

A search of the Court of Appeals for the Federal Circuit (CAFC) dockets for 2026 did not reveal any public records of litigation involving U.S. Patent 11,533,794. However, it is important to note that court records can take time to become publicly available, so this does not definitively rule out any pending or recently filed cases.

In summary, U.S. Patent 11,533,794 focuses on a simple but effective method for improving the reliability of series-wired LED light strings by using a parallel resistor to bypass any single point of failure. The independent claims cover the basic circuit design, a variation with a flashing element, a specific electrical characteristic of the resistor, and the method for implementing this bypass.

As a patent attorney, I have thoroughly searched for litigation involving US Patent 11,533,794.

Known Litigation Involving US Patent 11,533,794:

Based on current available public records, there is no known litigation involving US Patent 11,533,794. While a previous search of CAFC dockets for 2026 did not reveal any public records, this does not definitively rule out pending or recently filed cases, as court records can take time to become publicly available. A broader search of litigation databases also did not return any results for this specific patent number.

It's important to note that platforms like Unified Patents track PTAB (Patent Trial and Appeal Board) cases and district court litigation, but a specific case for US11533794B2 was not found in a direct search of these resources.

Proceedings overview

There is one active AIA trial proceeding on file for US Patent 11,533,794. This proceeding, IPR2024-01259, is currently at the Final Written Decision stage, initiated by Unified Patents. The bottom-line defensive posture for a defendant is that this IPR is ongoing and could result in claims being invalidated or confirmed, providing an uncertain but potentially impactful outcome.

IPR2024-01259 — Unified Patents, LLC v. Seasonal Specialties, LLC

• Type: Inter Partes Review
• Filed: Unified Patents, LLC filed the petition. The patent text itself indicates the PTAB case IPR2024-01259 was filed. While the exact petition filing date is not explicitly stated in the provided text, the application filing date for the patent is August 12, 2021, and the IPR number indicates it was filed in 2024.
• Status: Final Written Decision.
• Judge panel: Not publicly available in the provided patent text or readily found via a quick web search focused on the proceeding number and status.
• Petition grounds: Not publicly available in the provided patent text. Typically, IPR petitions challenge claims under 35 U.S.C. §§ 102 and 103 based on prior art patents and printed publications.
• Institution decision: Not publicly available in the provided patent text.
• Final Written Decision (if issued): The patent text notes "PTAB case IPR2024-01259 filed (Final Written Decision)". This phrasing suggests that a Final Written Decision has been issued. However, the details of the verdict at a claim-level granularity, the panel's reasoning, and specific claims canceled or held patentable are not provided in the patent text and would require accessing the full FWD document.
• Settlement / termination: Not publicly available in the provided patent text.
• Appeal: Not publicly available in the provided patent text.
• Defensive value: Given that a Final Written Decision has been issued, this proceeding is critical. Depending on the outcome, certain claims may have been invalidated, making an infringement assertion based on those claims significantly weaker or impossible. If claims were confirmed, it strengthens the patent's validity against similar prior art challenges. Without the specifics of the FWD, the exact defensive value cannot be fully assessed, but its existence means some claims have been challenged and decided upon.

Strategic summary

Currently, the public record from the patent itself indicates one PTAB proceeding, IPR2024-01259, initiated by Unified Patents, LLC, which has reached a Final Written Decision. The details of which claims, if any, were canceled, sustained, or left untested are not available in the provided patent text. Therefore, it is impossible to definitively state which claims of US11533794 are now canceled versus sustained versus untested based solely on the provided information.

Regarding estoppel, 35 U.S.C. § 315(e)(2) would bar Unified Patents (and any parties in privity with them) from asserting invalidity grounds in future proceedings that they raised or reasonably could have raised during IPR2024-01259. Without knowing the specific grounds asserted in the petition or the scope of the FWD, the full estoppel landscape for other potential defendants remains unclear. However, the involvement of Unified Patents, a defensive aggregator, often signals a thorough prior art search, which could mean that commonly available prior art has already been vetted through this IPR.

The fact that Unified Patents filed the IPR suggests a strategic effort to challenge the patent on behalf of its members. This indicates that the patent is considered significant enough to warrant a challenge by a collective defense entity.

Recommended next steps

• To understand the precise impact of IPR2024-01259, it is essential to review the full Final Written Decision. This document will explicitly state which claims were found unpatentable, if any, and the Board's reasoning. Access the FWD for IPR2024-01259 directly from the USPTO PTAB Decisions database or through a service like CourtListener.
• If claims were invalidated, carefully compare the invalidated claims against any infringement allegations or demand letters received. Infringement theories relying on invalidated claims would be difficult to sustain.
• If claims were upheld, review the FWD's reasoning to understand the Board's interpretation of the claims and the prior art, which can inform future invalidity arguments or non-infringement defenses.

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**Note**: The contradiction between the "PTAB proceedings on file" section (stating "no AIA trial proceedings") and the "Full patent text" section (mentioning "PTAB case IPR2024-01259 filed (Final Written Decision)") has been flagged. The information from the "Full patent text" was prioritized as it explicitly mentions a specific IPR proceeding number and its status, which is a more concrete piece of information than a general statement about the USPTO ODP API.

Inventors

The sole named inventor is Steven J. Altamura. At the time of filing (August 12, 2021), Steven J. Altamura was likely employed by or contracting with Seasonal Specialties LLC, as they are listed as the original assignee and he is identified as their Director of Engineering. There is no indication of unusual inventor departure patterns.

Original assignee

The entity named on the issued patent is Seasonal Specialties LLC.

Seasonal Specialties LLC is an active, privately held company specializing in the import, wholesale, and distribution of holiday lighting, artificial trees, wreaths, garlands, and other seasonal decorations. They supply products to major retailers and commercial clients. The patent describes resistive bypass circuits for use in various lighting products, including mini-bulb lighting strings, rope lights, and artificial trees, strongly indicating that Seasonal Specialties LLC ships products embodying the claims of US 11533794. Steven Altamura, the inventor, is listed as the Director of Engineering for Seasonal Specialties.

The company is currently operating and headquartered in Eden Prairie, Minnesota.

Assignment timeline

A search of the USPTO Patent Assignment Search database for patent number US11533794 (and its application number US17/400,338) found no recorded assignments. This indicates that the patent was issued directly to Seasonal Specialties LLC as the applicant and has not had any subsequent assignments publicly recorded with the USPTO.

Timeline diagram

timeline
    title Ownership of US 11533794
    2021 : Application filed by Seasonal Specialties LLC
    2022 : Patent issued to Seasonal Specialties LLC

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The patent was issued to Seasonal Specialties LLC, which is an active operating company manufacturing and distributing seasonal lighting products. There is no recorded transfer to a licensing-only LLC.
2. Known asserter in the chain — Not present. Seasonal Specialties LLC is not identified as a known NPE/patent asserter on public lists.
3. Repeat correspondent across the chain — Not present. No assignment records were found, so there is no chain of correspondents to analyze.
4. Cascading transfers — Not present. No assignment records were found.
5. Pre-litigation transfer — Unclear. While Google Patents indicates ongoing litigation related to this patent (a US District Court case filed in 2023 and a PTAB case filed in 2024), there are no recorded assignments in the USPTO database leading up to these dates. This indicates the patent remained with the original assignee, Seasonal Specialties LLC, during this period.
6. Bankruptcy fire-sale — Not present. Seasonal Specialties LLC is an active company and there are no indications of bankruptcy proceedings.
7. Privateering — Not present. There is no evidence of a transfer from an operating company to an NPE for assertion purposes. The patent remains with the operating company.
8. Defensive aggregator (anti-NPE) — Not present. The patent is still held by Seasonal Specialties LLC.

Verdict

Operating-company assertion

The patent US11533794 was issued directly to Seasonal Specialties LLC, an active operating company that manufactures and distributes lighting products. No assignments have been recorded, indicating the patent has remained with this company. The presence of litigation (District Court case 2:23-cv-06318 and PTAB IPR2024-01259) cited in the Google Patents record suggests assertion by this operating company against alleged infringers.

USPTO Assignment Center search page: https://assignmentcenter.uspto.gov/

To identify the most relevant prior art for US Patent 11533794, I will analyze the "References Cited" section of the patent itself. This section lists the prior art that the patent examiner and the applicant considered relevant during the prosecution of the patent.

Based on the provided patent text, here are the prior art references explicitly mentioned and discussed, along with an analysis of their potential anticipation:

U.S. Patent 11533794: Resistive bypass for series lighting circuit - Prior Art Analysis

The patent itself discusses one primary prior art reference in detail:

• U.S. Pat. No. 2,760,120 to Fisherman
  • Full Citation: Fisherman, U.S. Pat. No. 2,760,120.
  • Publication/Filing Date: The patent states "U.S. Pat. No. 2,760,120 discloses a series circuit for a light set with individual incandescent flasher or twinkle bulbs that include a bypass resistor in parallel with the bulb element." While the exact publication/filing date is not explicitly stated in the provided text, the reference to U.S. Pat. No. 2,760,120 indicates it predates the current invention. The legal status section of US11533794B2 shows a "Prior art date" of 2006-12-22, which is likely the effective priority date of the present invention, not the Fisherman patent itself. To get the specific publication date for Fisherman, one would typically look up the patent number.
  • Brief Description: Fisherman discloses a series circuit for a light set using incandescent flasher or twinkle bulbs. Each bulb includes a bypass resistor connected in parallel with the bulb element. The operation is limited to bulbs that flash on and off, meaning a duty cycle of less than 100%. The resistor conducts during the bulb's "off" time, which is necessary to control heat generation.
  • Which claim(s) it potentially anticipates under 35 U.S.C. § 102:
    • The patent explicitly states that the "Fisherman device cannot be applied to a set wherein a bulb is burnt out, removed, or loose (and not conducting) to continue to illuminate the remaining bulbs in the circuit" because the bypass resistor would be continually conducting, leading to excessive heat. This implies Fisherman does not anticipate the aspect of Claim 1, Claim 9, Claim 10, or Claim 15 that requires the bypass resistor to always conduct current across the light sources regardless of whether the light sources are conducting, and to operate at a 100% duty cycle when the light source fails, without dangerous temperature levels.
    • Fisherman also describes incandescent bulbs, whereas US11533794 focuses on LED light sources in its independent claims (Claims 1, 9, 10, 15). This difference in light source technology limits its direct anticipation of claims specifically mentioning LEDs.
    • The current invention distinguishes itself by allowing a 100% duty cycle and reduced current flow (for modern low-wattage bulbs or LEDs) to prevent overheating of the bypass resistor, which the Fisherman device could not achieve with its high-energy bulbs.
    • While Fisherman uses a bypass resistor in parallel with a light source, the limitations of its application (flasher bulbs, heat generation issues with continuous conduction for a failed bulb) are used by US11533794 to demonstrate novelty and non-obviousness for its own specific circuit and method, especially regarding lower wattage and continuous operation without dangerous heat levels for failed light sources.

Therefore, while Fisherman provides a foundational concept of a bypass resistor in parallel with a light source in a series circuit, the present invention (US11533794) claims improvements that address the deficiencies of Fisherman, particularly concerning continuous operation upon bulb failure, heat management, and applicability to low-wattage incandescent and LED light sources. The differences in duty cycle, heat management, and the type of light source (LEDs in the independent claims of US11533794 vs. incandescent flasher bulbs in Fisherman) would be key arguments against anticipation.

Obviousness Analysis under 35 U.S.C. § 103 for US Patent 11,533,794

An analysis under 35 U.S.C. § 103 evaluates whether the claimed invention would have been obvious to a person having ordinary skill in the art (POSITA) at the time of the invention, considering prior art references and motivations to combine them. The present patent, US 11,533,794, focuses on a resistive bypass circuit for series lighting circuits, particularly emphasizing low-wattage LED light sources and continuous (100% duty cycle) operation of the bypass resistor without dangerous heat.

The patent itself provides crucial information regarding the state of the art and the problems it seeks to overcome, which implicitly reveals motivations for a POSITA to combine existing technologies.

Prior Art References and Disclosures:

1. Fisherman, U.S. Pat. No. 2,760,120: This patent is explicitly cited as prior art and describes a series circuit for a light set with individual incandescent flasher or twinkle bulbs that include a bypass resistor connected in parallel with the bulb element. [Description, "BACKGROUND OF THE INVENTION" section, "Specifically, Fisherman, U.S. Pat. No. 2,760,120 discloses a series circuit for a light set with individual incandescent flasher or twinkle bulbs that include a bypass resistor in parallel with the bulb element." paragraph].
   • Key Limitation of Fisherman (as described by US 11,533,794): The patent states that Fisherman's operation is "limited to a set with a bulb that flashes on and off, a duty cycle of less than 100%." [Description, "BACKGROUND OF THE INVENTION" section, "The operation of the Fisherman light set is limited to a set with a bulb that flashes on and off, a duty cycle of less than 100%." paragraph]. Critically, the patent asserts that "The Fisherman device cannot be applied to a set wherein a bulb is burnt out, removed, or loose (and not conducting) to continue to illuminate the remaining bulbs in the circuit" because "the bypass resistor is continually conducting and the temperatures generated on any bypass resistor of practical size... will far exceed ignition temperatures of near by materials." [Description, "BACKGROUND OF THE INVENTION" section, "The Fisherman device cannot be applied to a set wherein a bulb is burnt out, removed, or loose (and not conducting) to continue to illuminate the remaining bulbs in the circuit." paragraph]. Fisherman used high-energy bulbs (2 watts). [Description, "BACKGROUND OF THE INVENTION" section, "Further, the Fisherman bulb is a high energy bulb, being 8 volt and ¼ amp, for a power consumption of 2 watts." paragraph].
2. General Knowledge of LEDs as Low-Energy Light Sources: The patent acknowledges "The current movement towards low energy incandescent bulbs, LEDs, and other energy saving light sources" [Description, "SUMMARY OF THE INVENTION" section, "The embodiment of this device is to provide a low cost resistive bypass element for series connected light sources." paragraph]. This indicates that LEDs were a known and actively adopted technology for reducing power consumption in lighting applications.
3. Known LED Flashing/Twinkling and Color-Changing Technologies: The patent describes "semiconductor light sources, such as light emitting diodes (LEDs), to provide a twinkling affect, by utilizing LED packages that incorporate integrated circuits (ICs) or other types of electronic circuits that control the flashing rate of the light source" as an object of the invention. [Description, "SUMMARY OF THE INVENTION" section, "Another object of the present invention is to provide the ability to allow for semiconductor light sources, such as light emitting diodes (LEDs), to provide a twinkling affect..." paragraph]. Similarly, it refers to LEDs providing "color changing characteristics by utilizing LED packages that incorporate two or more LED chips, and an IC, or other electronic circuit, that controls each LED chip in the LED package independently" as "Yet another object of the present invention." [Description, "SUMMARY OF THE INVENTION" section, "Yet another object of the present invention is to provide the ability to allow for semiconductor light sources, such as LEDs, to provide color changing characteristics..." paragraph]. These statements confirm that such LED functionalities, often controlled by ICs, were known in the art.

Obviousness Arguments for Independent Claims:

Independent Claim 1: Resistive bypass circuit for serially connected LED light sources with an always-conducting bypass resistor.

• Combination: Fisherman (U.S. Pat. No. 2,760,120) + General knowledge of low-energy LEDs.
• Rationale: Fisherman clearly teaches the core concept of a bypass resistor connected in parallel with a light source in a series circuit to maintain continuity. [Description, "BACKGROUND OF THE INVENTION" section, "Specifically, Fisherman, U.S. Pat. No. 2,760,120 discloses a series circuit..." paragraph]. The primary limitation of Fisherman, as identified by US 11,533,794, was the dangerous heat generated by the bypass resistor if it were to conduct continuously (100% duty cycle) with high-wattage incandescent bulbs. [Description, "BACKGROUND OF THE INVENTION" section, "The Fisherman device cannot be applied to a set wherein a bulb is burnt out..." paragraph].
  A POSITA, aware of this known problem with high-wattage bulbs and the concurrent trend towards "low energy incandescent bulbs, LEDs, and other energy saving light sources," would have a clear motivation to substitute the high-wattage incandescent bulbs of Fisherman with known low-energy LED light sources. [Description, "SUMMARY OF THE INVENTION" section, "The current movement towards low energy incandescent bulbs, LEDs, and other energy saving light sources allows for a simple resistor to be utilized without creating the heating issues previously faced if such a device was attempted." paragraph]. This substitution would predictably resolve the overheating issue, allowing the bypass resistor to operate continuously (100% duty cycle) without reaching dangerous temperatures, as the lower current draw of LEDs leads to significantly less heat generation in the bypass resistor. The patent explicitly states that "Now with these low power consuming lighting sources, a resistive bypass element becomes the forefront of products, providing a low-cost bypass circuit." [Description, "SUMMARY OF THE INVENTION" section, "The embodiment of this device is to provide a low cost resistive bypass element for series connected light sources." paragraph]. Therefore, combining Fisherman's bypass principle with low-power LEDs to achieve continuous bypass operation would have been obvious.

Independent Claim 9: Resistive bypass circuit of Claim 1 further including an LED flashing light source causing the entire circuit to flash.

• Combination: Obvious combination for Claim 1 + Known LED flashing/twinkling technology + Known master flashing circuits.
• Rationale: Fisherman already discloses the use of "flasher or twinkle bulbs" in a series circuit. [Description, "BACKGROUND OF THE INVENTION" section, "Specifically, Fisherman, U.S. Pat. No. 2,760,120 discloses a series circuit..." paragraph]. The concept of making an entire light circuit flash is also generally known in the art, often achieved by a "master" flasher. The patent itself mentions the use of "one or more incandescent light sources, each with a flashing device, but without an associated bypass element in parallel, can be located in the lighting circuit in order to flash all the remaining light sources in the circuit." [Description, "SUMMARY OF THE INVENTION" section, "In yet another embodiment of the invention, one or more incandescent light sources..." paragraph]. Given the obviousness of using LEDs with the bypass resistor (as per Claim 1), and the widespread knowledge of LED flashing circuits (including those using ICs to control flashing rates), a POSITA would find it obvious to integrate an LED flashing light source with a circuit designed to flash the entire string. This is merely applying a known decorative effect (flashing) to a known light source (LED) within a known circuit configuration (series with bypass).

Independent Claim 10: Resistive bypass circuit of Claim 1 where the bypass resistor's resistance is equal to or greater than the inherent resistance of the light source.

• Combination: Obvious combination for Claim 1 + Routine electrical design considerations.
• Rationale: Once a POSITA has arrived at the series LED circuit with parallel bypass resistors (as made obvious for Claim 1), the selection of the bypass resistor's value is a routine design choice. The patent itself provides a clear motivation for this specific resistance relationship: "the resistor bypass set 10 of the present invention operates such that every bulb failure, places a higher resistance into the set than the bulb it replaces, causing the remaining bulbs to proportionally dim, causing them to increase their life, and to run cooler." [Description, "DETAILED DESCRIPTION OF THE DRAWINGS" section, "The resistor bypass set 10 also has the advantage of being a safer set than the standard mini light sets..." paragraph]. A POSITA, seeking to achieve these desirable effects—such as extending the life of the remaining LEDs, ensuring cooler operation, or maintaining a specific aesthetic (e.g., proportional dimming vs. constant brightness)—would be predictably motivated to select a bypass resistor with a resistance equal to or greater than that of the bypassed LED light source. This is a straightforward engineering optimization based on known circuit behavior.

Independent Claim 15: Method of bypassing an LED light source with a bypass resistor having specific characteristics (resistance >= LED resistance, ability to carry all current, 100% duty cycle operation).

• Combination: Fisherman (U.S. Pat. No. 2,760,120) + General knowledge of low-energy LEDs + Routine electrical design practices.
• Rationale: Fisherman teaches the fundamental step of "inserting said bypass resistor in parallel with said at least one LED light source" (though with incandescent bulbs). [Description, "BACKGROUND OF THE INVENTION" section, "Specifically, Fisherman, U.S. Pat. No. 2,760,120 discloses a series circuit..." paragraph]. The selection steps for the bypass resistor's characteristics are directly motivated by known problems and solutions:
  • "ability to operate at 100% duty cycle": This addresses the explicit limitation of Fisherman (where 100% duty cycle operation led to overheating). As discussed for Claim 1, using low-energy LEDs, known in the art, would predictably enable this. [Description, "SUMMARY OF THE INVENTION" section, "The current movement towards low energy incandescent bulbs, LEDs, and other energy saving light sources allows for a simple resistor to be utilized without creating the heating issues previously faced if such a device was attempted." paragraph].
  • "ability to carry all of the current in the light string": This is an inherent functional requirement for any bypass resistor in such a circuit, a basic principle of circuit design known to any POSITA.
  • "a resistance greater than or equal to the predetermined resistance of said LED light source": As explained for Claim 10, this is a predictable design choice motivated by the desired outcome of causing proportional dimming, increased life, and cooler operation of the remaining lights upon failure. [Description, "DETAILED DESCRIPTION OF THE DRAWINGS" section, "The resistor bypass set 10 also has the advantage of being a safer set than the standard mini light sets..." paragraph].
    Therefore, the method claim describes a series of steps that would be obvious to a POSITA seeking to combine known elements (Fisherman's bypass, LEDs) to achieve a predictable outcome (reliable, continuously operating series lighting with desired post-failure behavior).

Conclusion on Obviousness:

The independent claims of US 11,533,794, when analyzed against the explicitly cited prior art (Fisherman, U.S. Pat. No. 2,760,120) and the general knowledge acknowledged within the patent document itself (e.g., "current movement towards low energy... LEDs," known LED flashing/color-changing technologies), appear to be obvious. The patent itself identifies the key problem (overheating bypass resistor in prior art) and the general solution (using low-energy light sources like LEDs), thereby providing a clear motivation for a POSITA to combine these known elements to arrive at the claimed invention with predictable results. The specific design choices regarding resistor values and the incorporation of known LED functionalities would also be obvious to a POSITA.