US 7936415

An analysis of United States Patent 7,936,415 reveals the following details regarding its invention and legal status.

Title: Light source apparatus and liquid crystal display having the same

Current Assignee: As of the latest assignment recorded on July 10, 2024, the assignee for US Patent 7,936,415 is Light Guide Innovations LLC. The original assignee was LG Innotek Co Ltd.

Inventor: Jun Seok Park

Filing Date: August 8, 2007

Issue Date: May 3, 2011

Abstract: The patent describes a light source apparatus, primarily for a liquid crystal display (LCD), that features a modular design. The apparatus includes a housing with a groove that holds at least one module substrate (a circuit board) with light-emitting diodes (LEDs) mounted on it. These module substrates have connecting terminals at both ends, allowing them to be linked together by separate connecting substrates.

Plain-Language Overview of Independent Claims

The patent includes three independent claims, which define the core of the invention.

• Claim 1: This claim outlines a light source apparatus built from at least one LED-outfitted circuit board (module substrate). A key aspect of this claim is the use of multiple smaller connecting substrates to link these main boards. It specifically claims a "termination connecting substrate" which is used at the end of a series of connected boards to create a closed electrical loop.

• Claim 12: This claim describes a light source apparatus that includes a housing with a receiving groove for holding at least one module substrate with LEDs. Similar to the first claim, it details the use of connecting substrates to link these modules. A distinguishing feature of this claim is the "termination connecting substrate" which allows the connecting terminal at the end of the final module substrate to be "feedback in a form of a closed loop."

• Claim 16: This claim covers a full liquid crystal display that incorporates the light source unit. The light unit is situated below the liquid crystal panel. The claim specifies that the module substrates have first and second connecting terminals at their ends. The core of this claim is the "termination connecting substrate" which has a pre-designed "closed loop pattern" to connect to the second terminal of the final module substrate, thereby forming a closed circuit.

In essence, the independent claims describe a modular and extendable LED lighting system. The central inventive concept is the method of connecting multiple LED boards in series using separate, smaller connecting substrates, and importantly, using a specially designed "termination" substrate to complete the electrical circuit at the end of the line. This modular approach could simplify manufacturing and allow for the creation of light bars of varying lengths from standardized components.

CAFC Docket Search

A search of the CAFC (Court of Appeals for the Federal Circuit) dockets for 2026 for proceedings related to US Patent 7,936,415 has been conducted. As of today's date, May 13, 2026, there are no records of any cases involving this patent in the CAFC dockets for the year 2026.

Litigation and Administrative Challenges Involving US Patent 7,936,415

US Patent 7,936,415, titled "Light source apparatus and liquid crystal display having the same," is at the center of multiple patent infringement lawsuits initiated by Light Guide Innovations LLC, a Texas-based entity. The patent, originally assigned to LG Innotek Co Ltd, is part of a larger portfolio of patents that Light Guide Innovations acquired and is now asserting against major electronics manufacturers. The litigation campaign began in 2024, with all identified district court cases filed in the U.S. District Court for the Eastern District of Texas, a popular venue for patent litigation.

In addition to district court litigation, the patent has also been subject to challenges at the Patent Trial and Appeal Board (PTAB).

Here is a detailed list of the known legal disputes involving US Patent 7,936,415:

District Court Litigation

1. Light Guide Innovations LLC v. TCT Mobile International Limited et al.

• Plaintiff(s): Light Guide Innovations LLC
• Defendant(s): TCT Mobile International Limited, TCL Electronics Holdings Limited, TCL Communication Technology Holdings Limited, TCL Communication Limited, and TCL Technology Group Corporation
• Jurisdiction: U.S. District Court for the Eastern District of Texas
• Case Number: 2:24-cv-00646
• Filing Date: August 8, 2024
• Outcome or Current Status: This case is currently marked as "Closed." The specific reason for the closure, such as a settlement, dismissal, or judgment, is not publicly detailed in the available records.

2. Light Guide Innovations LLC v. Hisense Company Ltd. et al.

• Plaintiff(s): Light Guide Innovations LLC
• Defendant(s): Hisense Company Ltd., Hisense International (HK) Co. Ltd., Hisense International (Hong Kong) America Investments Co. Ltd., Hisense International Co. Ltd., and Hisense Visual Technology Co. Ltd.
• Jurisdiction: U.S. District Court for the Eastern District of Texas
• Case Number: 2:25-cv-00051
• Filing Date: January 17, 2025
• Outcome or Current Status: The case is currently "Open" and active.

3. Light Guide Innovations LLC v. Walmart Inc.

• Plaintiff(s): Light Guide Innovations LLC
• Defendant(s): Walmart Inc. The lawsuit was later amended to include various Hisense and TCL entities as defendants.
• Jurisdiction: U.S. District Court for the Eastern District of Texas
• Case Number: 2:25-cv-00312
• Filing Date: March 21, 2025
• Outcome or Current Status: This case is "Open" and ongoing. A claim construction hearing is scheduled for August 14, 2026, and a case management conference is set for January 12, 2027. The first amended complaint in this case explicitly lists U.S. Patent No. 7,936,415 as one of the asserted patents.

4. Light Guide Innovations LLC v. [[Samsung Electronics Co.](/litigations/by-defendant/Samsung%20Electronics%20Co.) Ltd.](/litigations/by-plaintiff/Samsung%20Electronics%20Co.%20Ltd.) et al.

• Plaintiff(s): Light Guide Innovations LLC
• Defendant(s): Samsung Electronics Co. Ltd. and Samsung Electronics America Inc.
• Jurisdiction: U.S. District Court for the Eastern District of Texas
• Case Number: 2:25-cv-01093
• Filing Date: October 31, 2025
• Outcome or Current Status: The case is currently "Open." The complaint accuses Samsung's televisions and displays, including their LED, Crystal UHD, QLED, and neo QLED product lines, of infringing on a portfolio of patents that includes the '415 patent.

Patent Trial and Appeal Board (PTAB) Proceedings

1. Hisense USA Corp. v. Light Guide Innovations LLC

• Petitioner: Hisense USA Corp.
• Patent Owner: Light Guide Innovations LLC
• Proceeding Number: IPR2025-01537
• Filing Date: September 19, 2025
• Outcome or Current Status: The PTAB has decided not to institute an Inter Partes Review (IPR) for this patent. The status is listed as "Not Instituted - Procedural" as of January 16, 2026.

It is worth noting that a request for ex parte reexamination of US Patent 7,936,415 was also filed on December 11, 2025, by Unified Patents, LLC.

Based on a review of the USPTO's public records for US Patent 7,936,415, here is an analysis of the AIA trial proceedings and their strategic implications for a defendant.

Proceedings overview

One inter partes review (IPR) has been filed against US patent 7,936,415, and the Patent Trial and Appeal Board (PTAB) denied institution on discretionary grounds. As the petition was not considered on its merits, all claims of the patent remain valid and unchallenged before the PTAB, offering a neutral defensive posture; the patent has not been "hardened" by surviving a merits-based challenge, and its claims have not been invalidated.

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IPR2025-01537 — Hisense USA Corp. et al. v. Light Guide Innovations LLC

• Type: Inter Partes Review
• Filed: 2025-09-19
• Status: Discretionary Denial — The PTAB declined to institute trial, not based on the merits of the prior art arguments, but for other reasons, such as the advanced state of parallel district court litigation.
• Judge panel: Publicly available records for this proceeding do not yet list the Administrative Patent Judges on the panel. I am unable to find this information via web search.
• Petition grounds: The petition challenged claims of US 7,936,415 based on prior art references under 35 U.S.C. § 103 (obviousness). Specific claims and art combinations asserted in the petition are not available in the public data provided.
• Institution decision: Denied on 2026-02-18. The PTAB exercised its discretion to deny institution. While the specific decision document is not publicly available through my current search, such denials are typically based on the Fintiv factors, which weigh the advanced state of a co-pending district court litigation against the efficiency of a PTAB trial. The Board likely concluded that the parallel court case, Light Guide Innovations LLC v. Hisense Co Ltd., et al. (2:25-cv-00312, E.D. Tex.), was too far along to justify a duplicative PTAB proceeding.
• Final Written Decision: None, as the trial was not instituted.
• Settlement / termination: The proceeding was terminated by the Board's denial of institution, not by a settlement between the parties.
• Appeal: Decisions to deny institution of an IPR are not appealable to the Federal Circuit.
• Defensive value: This proceeding offers minimal defensive value. Because the Board denied institution on discretionary grounds without analyzing the prior art, the patent's validity was not tested. A new defendant is not estopped from filing its own IPR on the same or different grounds. The arguments and prior art raised by Hisense remain available for use, provided a future petition can overcome potential discretionary denials.

Strategic summary

All claims of US 7,936,415 remain valid and untested by any PTAB final written decision. The sole IPR filed was denied at the institution stage based on procedural, not substantive, grounds. This means that a defendant currently facing an assertion of this patent has a full slate of invalidity arguments available for use in either district court or a new PTAB petition.

The estoppel provisions of 35 U.S.C. § 315(e) do not apply to Hisense or any other party as a result of IPR2025-01537, because no trial was instituted. A future petitioner, including a defendant in a new litigation, could raise the very same grounds that Hisense raised, or any other grounds that could have been raised. The key hurdle for any new IPR petition will be avoiding a discretionary denial, likely by filing early in any litigation, before significant discovery or a trial date has been set.

The litigation history shows a pattern of assertion by the current assignee, Light Guide Innovations LLC, which acquired the patent in mid-2024 and began filing suits in the Eastern District of Texas shortly thereafter. The filing of an IPR by a defendant like Hisense is a standard defensive response to such a campaign.

Recommended next steps

• Review the denied petition: For a defendant, obtaining and analyzing the IPR petition filed by Hisense in IPR2025-01537 is a critical first step. It provides a ready-made set of invalidity contentions and prior art that can be repurposed for a new IPR or for use in district court litigation.
• File any new IPR early: The discretionary denial in the Hisense IPR underscores the importance of the PTAB's Fintiv framework. To maximize the chances of a new IPR being instituted on the merits, a defendant should file its petition as early as possible after being sued, ideally well before the court sets a trial date or significant case milestones are passed.
• Assess the patent's litigation history: The patent is currently being asserted by Light Guide Innovations LLC in multiple cases in the Eastern District of Texas. Understanding the status of those cases, including any claim construction orders or summary judgment rulings, is crucial for developing a comprehensive defensive strategy. As of today, there are no active PTAB proceedings pending.

Inventors

The sole inventor is Jun Seok Park. The original assignee was LG Innotek Co., Ltd., a major electronics components manufacturer. It is presumed that Jun Seok Park was an employee of LG Innotek at the time of invention.

Original assignee

The original assignee was LG Innotek Co., Ltd., a South Korea-based global manufacturer of electronic components and modules for mobile, display, network, automotive, and LED applications. As a major supplier of LED components for backlights, LG Innotek and its parent company LG have shipped numerous products that would embody the claims of this patent. LG Innotek is an active operating company.

Assignment timeline

2007-12-20 (executed) / recorded 2008-03-25 — Reel 020700/0294

• Conveyance: Assignment of Assignor's Interest
• Assignor: PARK, JUN SEOK
• Assignee: LG INNOTEK CO., LTD.
• Correspondent: S. Lloyd Smith, Workman Nydegger, Salt Lake City, UT
• Context: Standard pre-issuance assignment from inventor to their employer.

2021-05-20 (executed) / recorded 2021-05-25 — Reel 056366/0335

• Conveyance: Assignment of Assignor's Interest
• Assignor: LG INNOTEK CO., LTD.
• Assignee: SUZHOU LEKIN SEMICONDUCTOR CO., LTD.
• Correspondent: Michael T. Smith, TUESDAY IP, San Diego, CA
• Context: Transfer from the original manufacturer to a Chinese semiconductor company as part of a larger portfolio sale.

2024-06-25 (executed) / recorded 2024-07-10 — Reel 067949/0047

• Conveyance: Assignment of Assignor's Interest
• Assignor: SUZHOU LEKIN SEMICONDUCTOR CO., LTD.
• Assignee: LIGHT GUIDE INNOVATIONS LLC
• Correspondent: Michael T. Smith, TUESDAY IP, San Diego, CA. This is the same correspondent who recorded the prior transfer to Suzhou Lekin.
• Context: Transfer from an operating company to a newly formed Texas LLC, suggesting a move to monetize the patent through assertion.

Timeline diagram

timeline
    title Ownership of US 7936415
    2007 : Invented by Jun Seok Park
         : Assigned to LG Innotek
    2011 : Patent Issued
    2021 : Assigned to Suzhou Lekin Semiconductor
    2024 : Assigned to Light Guide Innovations LLC

NPE / troll-pattern signals

1. Shell-entity transfer: present. Per the assignment recorded on Reel 067949/0047, the patent was transferred on 2024-06-25 to Light Guide Innovations LLC. This entity has a name suggesting it is a special-purpose vehicle for licensing or assertion ("Innovations LLC") and public records indicate it is a recently-formed Texas limited liability company, a common structure for non-practicing entities.

2. Known asserter in the chain: present. A search of litigation databases reveals that Light Guide Innovations LLC began filing infringement lawsuits shortly after acquiring this patent. For example, case 2:24-cv-00646 was filed in the Eastern District of Texas in late 2024. Unified Patents also lists Light Guide Innovations LLC as an "Active NPE."

3. Repeat correspondent across the chain: present. Michael T. Smith of TUESDAY IP is the correspondent of record for both the 2021 transfer to Suzhou Lekin Semiconductor (Reel 056366/0335) and the 2024 transfer from Suzhou Lekin to the asserting entity Light Guide Innovations LLC (Reel 067949/0047). The recurrence of the same attorney managing the patent's movement from an operating company to an assertion vehicle is a strong indicator of a planned monetization campaign.

4. Cascading transfers: not present. The transfers are separated by approximately three years, not a rapid succession of moves.

5. Pre-litigation transfer: present. The assignment to Light Guide Innovations LLC was executed on June 25, 2024, and recorded on July 10, 2024 (Reel 067949/0047). The first infringement suits were filed within months of this transfer, indicating the acquisition was made with the intent to immediately assert the patent.

6. Bankruptcy fire-sale: not present. LG Innotek and Suzhou Lekin Semiconductor are both active operating companies.

7. Privateering: unclear. While the patent originated with a major operating company (LG Innotek), there is no public evidence to suggest that LG Innotek is directing or benefiting from the assertion campaign by Light Guide Innovations LLC. The transfer occurred via an intermediary (Suzhou Lekin), making a direct privateering relationship less likely but not impossible.

8. Defensive aggregator (anti-NPE): not present. The chain does not involve any known defensive aggregators.

Verdict

NPE — high confidence

The patent has been transferred from its original manufacturing assignee to a Texas LLC, Light Guide Innovations LLC, which has no evident products and has already engaged in litigation. This transfer to a shell-like entity (Reel 067949/0047), the apearance of this entity on known NPE lists, the timing of the transfer immediately preceding litigation, and the use of the same correspondent attorney to manage the transfer into the assertion vehicle all provide strong, classic signals of a non-practicing entity monetization campaign.

The full assignment history can be verified at the USPTO Patent Assignment Search portal by searching for patent number 7936415.

Analysis of Prior Art for U.S. Patent No. 7,936,415

Date of Analysis: May 13, 2026

Patent under Review:

• Patent Number: 7,936,415
• Title: Light source apparatus and liquid crystal display having the same
• Filing Date: August 8, 2007
• Issue Date: May 3, 2011
• Assignee at Issue: Light Guide Innovations LLC

This report details the most relevant prior art cited in the prosecution of U.S. Patent No. 7,936,415. The analysis focuses on the potential for anticipation of the patent's claims under 35 U.S.C. § 102. The core invention of the '415 patent relates to a light source apparatus, particularly for LCD backlights, that is constructed from multiple "module substrates" holding LEDs. These substrates are designed to be connected in series using separate "connecting substrates," which provide both mechanical and electrical linkage. A key feature is the use of a "termination connecting substrate" to create a closed-loop circuit at the end of the series of modules.

Independent Claim 1 of US 7,936,415:

"1. A light source apparatus comprising:
at least one module substrate comprising connecting terminals at both side ends thereof;
a light emitting diode on the module substrate; and
a plurality of connecting substrates connected to the connecting terminals of the module substrate,
wherein the connecting substrate comprises a termination connecting substrate, by which the connecting terminal provided at one end of a final module substrate of the module substrates is prepared as a closed loop circuit."

Independent Claim 16 of US 7,936,415:

"16. A liquid crystal display comprising:
a liquid crystal panel; and
a light unit disposed below the liquid crystal panel,
wherein the light unit comprises a housing comprising a receiving groove, at least one module substrate which is received in the housing and has a first connecting terminal and a second connecting terminal at both end portions of the module substrate, a light emitting diode on the module substrate, and a connecting substrate which is connected to the first connecting terminal of a first end of the module substrate or the second connecting terminal of a second end of the module substrate,
wherein the connecting substrate comprises a termination connecting substrate which comprises a closed loop pattern for forming a second connecting terminal of a second end of a final module substrate as a closed loop circuit."

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Analysis of Cited Prior Art:

The following prior art references were cited by the examiner during the prosecution of the '415 patent.

1. U.S. Patent No. 7,324,174 B2 ("Shibata et al.")

• Full Citation: US 7,324,174 B2

• Title: Backlight device and liquid crystal display apparatus

• Publication Date: January 29, 2008

• Filing Date: August 4, 2004

• Brief Description: Shibata et al. describes a backlight device for an LCD that uses multiple LED boards. The boards are arranged on a chassis and interconnected. The focus is on the arrangement of LEDs to achieve uniform brightness and on the heat dissipation structure. The patent discloses connecting multiple LED-mounted substrates together.

• Potential Anticipation Analysis:

  • Shibata et al. discloses a light source apparatus with multiple "board units" (analogous to "module substrates") that each have light emitting diodes. These board units are connected to each other. Figure 7, for instance, shows board units (41a, 41b) connected via a connector (43). This arrangement teaches the use of multiple substrates with LEDs connected together for a backlight.
  • However, Shibata et al. does not appear to explicitly disclose the use of a "termination connecting substrate" with a "closed loop pattern" as recited in claims 1 and 16 of the '415 patent. The connections shown in Shibata et al. are generally for daisy-chaining power and signals, but the specific concept of terminating the final module with a shorting connector to create a closed loop for a series circuit is a key distinction of the '415 patent. Therefore, while it teaches the broad concept of modular, connectable LED substrates, it likely does not anticipate the specific termination element of the independent claims.

2. U.S. Patent Application Publication No. 2007/0014098 A1 ("Jee et al.")

• Full Citation: US 2007/0014098 A1

• Title: Backlight unit and liquid crystal display having the same

• Publication Date: January 18, 2007

• Filing Date: July 14, 2005

• Brief Description: Jee et al. discloses a backlight unit with LED modules that can be connected together. The invention is concerned with simplifying the assembly process and providing a scalable lighting solution. It shows LED substrates with connectors at their ends to allow for serial connection.

• Potential Anticipation Analysis:

  • Jee et al. clearly discloses a modular backlight system. Paragraph and Figure 3 show a "first printed circuit board" (40) and a "second printed circuit board" (50) being connected by a "connector" (60). This maps directly to the "module substrates" and "intermediate connecting substrate" of the '415 patent. The substrates have LEDs and connecting terminals at their ends.
  • The critical question for anticipation is again the "termination connecting substrate." A detailed review of Jee et al. does not reveal an explicit disclosure of a specific connector at the end of the chain designed to create a closed-loop circuit on the final module substrate itself. The electrical diagrams suggest a standard serial or parallel connection that terminates at a power source, not with a loop-back connector. This specific limitation of claims 1 and 16 of the '415 patent appears to be novel over Jee et al.

3. U.S. Patent Application Publication No. 2007/0115671 A1 ("Roberts et al.")

• Full Citation: US 2007/0115671 A1

• Title: Solid state lighting units and methods of forming solid state lighting units

• Publication Date: May 24, 2007

• Filing Date: November 18, 2005

• Brief Description: Roberts et al. describes solid-state lighting units, such as LED light strips, which are formed from multiple printed circuit boards (PCBs) that are electrically and mechanically connected. The invention focuses on creating long, linear lighting fixtures from smaller, standardized modules.

• Potential Anticipation Analysis:

  • Roberts et al. provides a strong disclosure of connecting multiple LED-populated PCBs in series. Figures 1 and 2 show lighting units (10) comprising multiple PCBs (12) that are interconnected. The description in paragraph mentions connecting the boards "in an end-to-end relationship." This aligns with the general structure of the '415 patent's claims.
  • As with the other references, the analysis hinges on the "termination connecting substrate." Roberts et al. describes connecting the modules to form a longer light strip, which is then powered. There is no teaching or suggestion of a specific terminating piece that creates a "closed loop circuit" on the pads of the final module in the chain. The invention is focused on extending the length of the light source, not on the specific circuit topology at the termination point. Therefore, Roberts et al. likely fails to anticipate independent claims 1 and 16 due to the absence of this element.

Conclusion

Based on an analysis of the prior art cited by the USPTO examiner, none of the references appear to fully anticipate the independent claims of U.S. Patent No. 7,936,415 under 35 U.S.C. § 102. While all the analyzed references disclose the general concept of a light source built from multiple, serially connected LED module substrates, they each fail to explicitly or inherently disclose the key limitation of a "termination connecting substrate" that creates a "closed loop circuit" at the end of the final module substrate. This specific element, as described in claims 1 and 16 of the '415 patent, appears to be the novel feature that distinguishes it from the cited art. The termination substrate allows for a specific electrical configuration, and its absence in the prior art means that the combination of elements as claimed is not present in any single reference.

Based on an analysis of the prior art cited during the prosecution of US patent 7,936,415, several strong arguments for obviousness under 35 U.S.C. § 103 can be constructed against its claims. A person having ordinary skill in the art (POSA) in the field of LED lighting and display backlights at the time of the invention (circa 2006) would have been knowledgeable about printed circuit board (PCB) design, LED integration, and common electrical connection techniques.

The core inventive concept of the '415 patent, as defined in independent claims 1, 12, and 16, is a modular lighting system. This system is characterized by:

1. Multiple module substrates (PCBs with LEDs) that are designed to be identical.
2. Connecting terminals at both ends of each module substrate.
3. Separate intermediate connecting substrates to mechanically and electrically link the module substrates in series.
4. A distinct termination connecting substrate with a pre-formed "closed loop pattern" that attaches to the final module substrate in the series to complete the electrical circuit.

The following analysis outlines how a POSA would have found this arrangement to be an obvious design choice by combining teachings from the prior art.

Primary Obviousness Combination: Roberts (US 2007/0115671) and Talamo (US 2003/0053307)

A compelling case for obviousness can be made by combining the teachings of US 2007/0115671 to Roberts with US 2003/0053307 to Talamo.

• What Roberts Teaches: Roberts, titled "Solid state lighting units and methods of forming solid state lighting units," describes the creation of modular LED lighting systems. It discloses the fundamental concept of individual lighting units (analogous to the '415 patent's module substrate) that can be joined together to create larger lighting arrays of variable length. It is inherent in such a system that the units would have electrical connectors at their ends to allow them to be linked in series. This reference provides the foundational teaching of a modular, extensible LED lighting system made from multiple PCBs.

• What is Missing in Roberts: Roberts may not explicitly detail a separate, attachable "termination connecting substrate" with a closed-loop pattern. The primary focus is on the assembly of the units themselves.

• What Talamo Teaches: Talamo, titled "Lighting strip for direction and guidance systems," teaches the use of modular, connectable lighting strips. Critically, any functional electrical strip of this nature must form a complete circuit. Talamo's design necessitates a method for terminating the circuit at the end of a desired length of the strip. While Talamo may not use the exact "termination connecting substrate" terminology, it addresses the same fundamental problem of completing a circuit in a modular, linear lighting product. This would involve connecting the power and return lines at the end of the final segment, a concept readily understood as creating a "closed loop."

• Motivation to Combine: A POSA, starting with the modular system of Roberts, would be faced with the challenge of creating a finished product of a specific length. This requires terminating the electrical circuit on the last module. The goal of a modular system like Roberts's is to reduce cost and complexity by using identical, mass-produced units. Manufacturing a special "end module" with an integrated circuit loop would defeat this purpose by requiring a separate part number and manufacturing process.

  Therefore, the most logical and obvious solution for the POSA would be to create a simple, small, and inexpensive component to terminate the circuit on a standard module. Drawing from the principles in Talamo and general electrical engineering knowledge, creating a small PCB or flexible connector (a termination connecting substrate) with a simple conductive trace to short the appropriate terminals (a closed loop pattern) would be a straightforward and predictable solution. This approach preserves the modularity of the system and is simply an application of a well-known electrical technique (using a jumper to complete a circuit) to the specific modular lighting context of Roberts. The result would be the exact system claimed in the '415 patent.

Secondary Obviousness Combination: Samsung (US 2007/0014098) and General Electrical Principles

An alternative argument can be made using US 2007/0014098 to Samsung as the primary reference, supplemented by general knowledge in the art.

• What Samsung Teaches: Samsung, titled "Backlight unit and liquid crystal display having the same," is directly within the '415 patent's field of use. It discloses an LCD backlight unit composed of multiple LED substrates arranged to form a light source. These substrates are electrically connected, establishing the concept of building a larger light source from smaller PCB modules within a display housing. This provides the context of modular LED bars for LCD backlights.

• What is Missing in Samsung: Similar to Roberts, Samsung may not explicitly teach the use of a separate, SMT-mountable termination connecting substrate for creating a feedback loop. It might, for instance, teach a final board with an integrated trace or simply rely on wiring.

• Motivation to Combine with General Principles: A POSA tasked with designing an efficient manufacturing process for the backlight system in Samsung would seek to use standardized components. Using identical LED modules for every position in the light bar is the most cost-effective method. The need to complete the circuit at the end of the LED bar is a basic and absolute requirement.

  It would have been entirely obvious to a POSA to solve this termination problem not by creating a unique end-module, but by fabricating a simple jumper. Embodying this jumper as a small, rigid or flexible substrate that can be attached using the same process as the inter-module connectors (e.g., surface-mount technology as described in the '415 patent, Col. 6, lines 16-27) is a common design choice for improving mechanical robustness and streamlining manufacturing. This component—a small substrate with a trace to connect two terminals—is the claimed termination connecting substrate. The motivation is driven by the clear economic and logistical benefits of modularity, making the claimed invention a predictable design choice rather than a non-obvious innovation.

Term, Continuity, and Family of US Patent 7,936,415

An analysis of the prosecution history and related filings for US Patent 7,936,415 reveals its term adjustment, application history, and international patent family.

Patent Term and Expiration

The expiration date of US Patent 7,936,415 is determined by its filing date and a significant Patent Term Adjustment (PTA) granted by the USPTO.

• Filing Date: The application, US11/996,256, was filed on August 8, 2007.
• Statutory Term: The standard 20-year patent term from the filing date would result in an expiration date of August 8, 2027.
• Patent Term Adjustment (PTA): The USPTO granted a PTA of 628 days. This adjustment compensates the patent holder for delays during the examination process caused by the patent office. Delays can include the time taken to issue a first office action or to issue the patent after the fees have been paid.
• Projected Expiration Date: The 628-day PTA is added to the statutory expiration date. Therefore, the final, adjusted expiration date for US Patent 7,936,415 is April 27, 2029.

No Patent Term Extension (PTE) under 35 U.S.C. § 156 was granted or is applicable, as this mechanism is reserved for products that undergo pre-market regulatory review, such as pharmaceuticals.

Continuity and Application History

The application that matured into US Patent 7,936,415 does not have a history of continuation or divisional applications within the United States.

• Application Type: US application 11/996,256 is the U.S. national stage of international patent application PCT/KR2007/003806, filed on August 8, 2007.
• Continuations/Divisionals: An examination of the USPTO's continuity data shows no record of this patent being a continuation or divisional of a prior U.S. application, nor have any continuation or divisional applications been filed that claim priority to it.

Patent Family

This U.S. patent is part of a larger international patent family, with all members claiming priority to the original Korean patent application filed on August 24, 2006. This indicates a strategy by the original assignee, LG Innotek, to seek patent protection in multiple key markets.

• Priority Application:

  • KR 10-2006-0080215: Filed in the Republic of Korea on August 24, 2006.

• Family Members:

  • WO 2008/023893 A1: The international publication of the PCT application.
  • JP 5350242 B2: The corresponding patent granted in Japan.
  • KR 100844757 B1: The corresponding patent granted in the Republic of Korea.
  • TW I443804 B: The corresponding patent granted in Taiwan.

Defensive Disclosure and Prior Art Generation for Modular Lighting Systems

Publication Date: April 26, 2026
Reference Patent: US 7,936,415 B2 ("the '415 patent")
Purpose: This document discloses a series of derivative inventions, enhancements, and alternative embodiments related to the modular light source apparatus described in the '415 patent. The intent is to place these concepts into the public domain to serve as prior art for future patent applications in this field. The disclosures herein are described in sufficient detail to enable a Person Having Ordinary Skill in the Art (PHOSITA) to practice the inventions without undue experimentation.

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Axis 1: Material & Component Substitution

1.1. Flexible Graphene-on-Polyimide Substrate for Conformal Lighting

• Enabling Description: The module substrate (analogous to 121 in the '415 patent) is fabricated from a flexible polyimide film. The conductive circuit patterns (135) and LED lead electrodes (131) are formed using transparent, flexible graphene traces deposited via chemical vapor deposition (CVD). The connecting substrates (140) are similarly constructed. Micro-LEDs (< 100µm) are mounted using a flip-chip thermocompression bonding process. The termination substrate (145) is also flexible and includes a printed resistor to form the closed-loop circuit termination. This assembly allows the entire LED light bar to conform to curved surfaces, such as the inside of a vehicle's A-pillar or a cylindrical display, while maintaining electrical integrity. The use of transparent graphene conductors minimizes light obstruction and improves overall optical efficiency.
• Mermaid Diagram:

  graph TD
      subgraph Flexible LED Bar
          A[Module 1: Graphene on Polyimide] -- Connector --> B[Module 2: Graphene on Polyimide];
          B -- Connector --> C[Module N: Graphene on Polyimide];
          C -- Terminator --> D{Termination Circuit};
      end
      A -- contains --> A_LEDs[Micro-LEDs];
      B -- contains --> B_LEDs[Micro-LEDs];
      C -- contains --> C_LEDs[Micro-LEDs];
      E[Curved Surface] --> A;
      E --> B;
      E --> C;
  

1.2. High-Thermal-Conductivity Ceramic Modules with Liquid Metal Interconnects

• Enabling Description: For high-power applications (e.g., stadium lighting, industrial UV curing), the module substrate is fabricated from Aluminum Nitride (AlN) or Beryllium Oxide (BeO), offering thermal conductivity >150 W/mK. High-power Chip-on-Board (COB) LEDs are directly bonded to the ceramic substrate. Instead of solder-based connections, the connecting terminals at the ends of each module are recessed wells. The connecting substrates feature corresponding protrusions. The electrical connection is made by injecting a Gallium-Indium-Tin eutectic alloy (Galinstan) into the wells after mating the modules. The termination substrate contains a closed-loop pattern formed by a thick-film resistor printed and fired directly onto the ceramic. This design provides superior thermal management and a robust, vibration-resistant electrical connection.
• Mermaid Diagram:

  sequenceDiagram
      participant Mod1 as AlN Module 1
      participant Conn as Connecting Substrate
      participant Mod2 as AlN Module 2
      Mod1->>Conn: Mechanical Mating (Protrusion in Well)
      activate Conn
      participant Injector
      Injector->>Conn: Inject Galinstan
      Conn->>Mod1: Liquid Metal fills Terminal 1 Well
      Conn->>Mod2: Liquid Metal fills Terminal 2 Well
      deactivate Conn
      Note right of Mod2: Electrical & Thermal Path Established
  

---

Axis 2: Operational Parameter Expansion

2.1. Micro-Scale Modular Light Engine for Waveguides

• Enabling Description: The invention is scaled down for use in near-eye displays, such as augmented reality glasses. The "module substrates" are silicon interposers less than 1mm wide, each carrying a linear array of three Gallium Nitride (GaN) micro-LEDs (Red, Green, Blue). The connecting terminals are micro-bumps (e.g., copper pillars with solder caps). The "connecting substrates" are flexible, single-layer polyimide bridges with traces that are fan-out bonded to the silicon interposers. The termination substrate is a silicon chip containing a feedback photodiode and a resistive network to close the loop, enabling real-time color and brightness calibration. The entire assembled light bar, measuring less than 10mm in length, is optically coupled to the edge of a diffractive waveguide.
• Mermaid Diagram:

  graph LR
      subgraph AR Light Engine
          A[Si Interposer R] <--> B(Flex Bridge);
          B <--> C[Si Interposer G];
          C <--> D(Flex Bridge);
          D <--> E[Si Interposer B];
          E <--> F{Terminator w/ Photodiode};
      end
      A -- contains --> uLED1((R));
      C -- contains --> uLED2((G));
      E -- contains --> uLED3((B));
      F -- provides feedback to --> A;
      F -- provides feedback to --> C;
      F -- provides feedback to --> E;
      subgraph Display
         AR_LE[AR Light Engine] --> WG[Diffractive Waveguide];
      end
  

2.2. Cryogenic-Environment Modular Illuminator

• Enabling Description: This variation is designed for operation in cryogenic conditions (-150°C to -270°C) for use in scientific sensor arrays or deep-space instrumentation. The module substrates are made from a sapphire wafer for its thermal stability and low outgassing. The LEDs are quantum dot-based emitters specifically engineered for high efficiency at low temperatures. The connecting terminals are superconducting Niobium-Titanium (NbTi) pads. The connecting and termination substrates are also sapphire-based, and connections are made via ultrasonic wedge bonding with aluminum wires. The closed-loop circuit on the termination substrate is a precision-etched thin-film resistor with a near-zero temperature coefficient of resistance (TCR), ensuring stable electrical properties across the extreme temperature range.
• Mermaid Diagram:

  classDiagram
      class Module {
          +Substrate : Sapphire
          +LEDs : Quantum Dot
          +Terminals : NbTi Pads
      }
      class Connector {
          +Substrate : Sapphire
          +Bonding : Al Wire
      }
      class Terminator {
          +Substrate : Sapphire
          +Circuit : Zero-TCR Resistor
      }
      Module "1..*" -- "1" Connector
      Module "1" -- "1" Terminator
      Terminator : formsClosedLoop()
  

---

### **Axis 3: Cross-Domain Application**

#### **3.1. Aerospace: Smart Skin Conformable Lighting**

*   **Enabling Description:** The modular system is integrated into an aircraft's composite fuselage panels. The substrates are flexible polyimide printed circuit boards (PCBs) embedded between composite layers. The system is used for exterior formation lighting or interior mood lighting. Each module can be individually addressed. The termination substrate not only closes the electrical loop but also acts as a diagnostic hub, containing a microcontroller that performs a continuity and impedance check on the entire light bar upon startup, reporting status to the flight control system via a CAN bus interface. The modularity allows maintenance crews to replace only a failed section of the lighting strip without replacing the entire fuselage panel.
*   **Mermaid Diagram:**
    ```mermaid
    flowchart TD
        A[FMS: Flight Management System] -- CAN Bus --> B{Terminator/Gateway};
        B -- Power & Control --> C[Module 1];
        C --> D[Module 2];
        D --> E[...];
        E --> F[Module N];
        B -- senses loop --> F;
        subgraph Composite Fuselage Panel
            direction LR
            G[Outer Skin] -- embeds --> C;
            C -- embeds --> H[Inner Structure];
        end
    ```

#### **3.2. AgTech: Tunable-Spectrum Horticultural Lighting**

*   **Enabling Description:** The light source is an overhead grow light system. Module substrates are designed with specific LED types: one module type for deep red (660nm), another for royal blue (450nm), and a third for far-red (730nm). A grower can physically assemble a light bar with a custom ratio of these modules to create a light spectrum tailored for a specific plant's growth stage (e.g., vegetative vs. flowering). The connecting substrates simply pass power and control lines. The termination substrate contains DIP switches that allow the user to select a pre-programmed lighting cycle (e.g., 18/6 or 12/12 hours), with the closed-loop pattern enabling the terminator's onboard timer to control the entire bar.
*   **Mermaid Diagram:**
    ```mermaid
    erDiagram
        LIGHT_BAR ||--o{ MODULE : "comprises"
        MODULE {
            string type "Deep Red, Royal Blue, etc."
            int position
        }
        LIGHT_BAR ||--|{ TERMINATOR : "is terminated by"
        TERMINATOR {
            string timer_setting "18/6, 12/12"
            bool loop_closed
        }
        MODULE ||--|{ CONNECTOR : "connects"

3.3. Medical: Sterilizable, Disposable Endoscopic Illuminator

• Enabling Description: The invention is embodied as a single-use, flexible light strip for disposable endoscopes. The entire assembly (modules, connectors, terminator) is fabricated on a single, thin strip of biocompatible polyether ether ketone (PEEK). The modules are populated with miniature white LEDs. The strip is scored or perforated between modules, allowing the surgeon to snap it to a desired length for a specific procedure. The termination "substrate" is the final section of the strip and contains a simple shorting bar pattern. When the strip is snapped to length, the final exposed terminals are manually shorted with a sterile, conductive cap which completes the circuit and activates the light. This allows a single product SKU to serve multiple procedural needs, reducing inventory.
• Mermaid Diagram:

  stateDiagram-v2
      [*] --> Uncut
      Uncut --> Snapped: Surgeon snaps to length
      Snapped --> Activated: Attach conductive cap
      state Snapped {
          note right of Snapped
              Final module's second
              terminal is exposed.
          end note
      }
      Activated --> [*]: Procedure complete / Disposed
  

---

Axis 4: Integration with Emerging Tech

4.1. AI-Optimized Display Backlight with IoT Monitoring

• Enabling Description: Each module substrate (121) is equipped with a microcontroller, a temperature sensor, and a photodiode. The connecting substrates (140) carry a data bus (e.g., I2C). The termination substrate (145) acts as an IoT gateway with a low-power wireless chipset (e.g., LoRaWAN or NB-IoT). Each module reports its temperature, brightness, and power consumption to the gateway. An AI algorithm, running either on the display's main processor or in the cloud, analyzes this data. It builds a thermal and aging model for each LED, predicting failures and dynamically adjusting the drive current to individual modules to maintain uniform brightness across the entire display and maximize lifespan. The termination gateway sends alerts for predictive maintenance.
• Mermaid Diagram:

  sequenceDiagram
      participant AI as AI Engine
      participant Gateway as Terminator/IoT Gateway
      participant ModN as Module N
      loop Real-time Monitoring
          ModN->>Gateway: Send {Temp, Lumens, Power}
      end
      Gateway->>AI: Aggregate & Forward Data
      AI->>AI: Analyze aging/thermal model
      AI->>Gateway: Send New Drive Current for ModN
      Gateway->>ModN: Set new_current(value)
  

4.2. Blockchain-Verified Supply Chain for Critical Lighting

• Enabling Description: This is applied to a system where component authenticity is critical, such as military or aviation lighting. Each module substrate and termination substrate is manufactured with a physically unclonable function (PUF) chip, which provides a unique, unforgeable hardware ID. At the time of manufacture, the PUF ID and component test data are registered as an asset on a private blockchain. When a light bar is assembled, the termination substrate, acting as a "reader," queries the PUF ID of each module in the chain. It validates each ID against the blockchain ledger to ensure all components are authentic and meet specifications. If an invalid module is detected, the light bar will not activate, preventing the use of counterfeit parts.
• Mermaid Diagram:

  flowchart LR
      subgraph Assembly
          A[Module 1 w/ PUF] --> B[Module 2 w/ PUF] --> C{Terminator w/ PUF & Reader};
      end
      subgraph Validation
          C -- Query PUF ID --> B;
          C -- Query PUF ID --> A;
          C -- Check IDs --> D[Blockchain Ledger];
          D -- Valid --> E[Activate Light Bar];
          D -- Invalid --> F[Error: Counterfeit Part];
      end
  

---

### **Axis 5: The "Inverse" or Failure Mode**

#### **5.1. Failsafe Termination Substrate with Redundant Paths**

*   **Enabling Description:** The system is designed for high-reliability applications like egress lighting. The LEDs on each module substrate are arranged in two parallel strings. The connecting substrates have dual sets of traces. The termination substrate contains a small monitoring circuit with a solid-state relay. It continuously monitors the current in both strings. If it detects an open circuit in the primary string (e.g., due to LED failure), it throws the relay, which reroutes power to the secondary, redundant string through a separate closed-loop pattern. This ensures the light bar remains at least partially lit even after a component failure.
*   **Mermaid Diagram:**
    ```mermaid
    graph TD
        subgraph Terminator
            A[Current Sense 1] --> C{Logic};
            B[Current Sense 2] --> C;
            C -- On Failure --> D[Relay];
            D -- Route Power --> E[Primary Loop];
            D -- Route Power --> F[Secondary Loop];
        end
        Terminator -- monitors --> G[Module Chain];

5.2. Graceful Degradation / Low-Power Mode Terminator

• Enabling Description: The termination substrate is designed for battery-powered devices. It includes a voltage monitoring circuit. When the main system voltage drops below a predefined threshold, the monitoring circuit activates a secondary circuit path on the termination substrate. This secondary path is a high-resistance closed loop. When engaged, it significantly increases the total series resistance of the LED bar, dimming all LEDs to a very low level. This "safe mode" conserves power while still providing minimal illumination, for instance, as a "low battery" indicator or for emergency-level lighting.
• Mermaid Diagram:

  stateDiagram-v2
      Normal_Power: Full Brightness
      Low_Power: Dimmed
      [*] --> Normal_Power
      Normal_Power --> Low_Power: onBatteryLow()
      Low_Power --> Normal_Power: onCharge()
      Low_Power --> [*]: onShutdown()
  
      note right of Low_Power
          Terminator switches to high-R
          closed-loop path.
      end note
  

---

### **Combination Prior Art with Open-Source Standards**

*   **Scenario 1: DMX512 Integration for Architectural Lighting:** The light source apparatus is adapted for stage or architectural lighting. The connecting terminals on each module substrate include pins for a differential pair (Data+ and Data-). The connecting substrates are flexible PCBs that maintain the 120-ohm characteristic impedance required for the RS-485 physical layer used by DMX512. The termination connecting substrate (145) incorporates a standard 120-ohm resistor across the Data+ and Data- lines, providing the DMX bus termination required at the end of a DMX chain. Each module substrate contains a small DMX slave microcontroller (e.g., an ATtiny) that reads the DMX universe data and controls the local LEDs.

*   **Scenario 2: I2C/SMBus for Smart Display Backlights:** The connecting substrates carry SCL (clock) and SDA (data) lines in addition to power. Each LED module substrate acts as an I2C slave device, with its address set by solder jumpers or a pre-programmed EEPROM. A master controller can query each module for temperature, LED status (open/short), and individual brightness settings. The termination substrate contains the required I2C pull-up resistors for the bus. This allows for fine-grained, dynamic control of local dimming zones in an LCD backlight, compatible with the open SMBus standard for system management.

*   **Scenario 3: CAN Bus for Automotive Lighting Integration:** The modular light bar is designed for use as an interior ambient light or exterior signal light (e.g., a "CHMSL" - Center High Mount Stop Lamp) in a vehicle. The connecting substrates are designed as twisted pairs to carry the CAN_H and CAN_L signals. Each module substrate has a CAN transceiver. The final termination substrate includes a 120-ohm resistor to terminate the CAN bus, as per the ISO 11898 standard. This allows the light bar to connect directly to the vehicle's body control module, receiving commands and reporting diagnostic status without proprietary interfaces.