US 8267537

Summary of U.S. Patent 8,267,537

A concise summary of U.S. Patent 8,267,537 is provided below, based on a review of the patent documentation and other publicly available information as of April 26, 2026.

Title: Backlight unit and display device having the same

Assignee: The current assignee of record is Light Guide Innovations LLC. The patent was originally assigned to LG Innotek Co., Ltd.

Inventors: Jun Seok Park

Filing Date: December 21, 2007

Issue Date: September 18, 2012

Abstract: The patent discloses a backlight unit and a display device incorporating it. The backlight unit comprises a light-emitting diode (LED) module, a case that supports the LED module and includes a "bending part" to guide and fix one end of the module, and a separate "fixing part" to secure the rest of the module to the case. This design is intended to simplify the replacement of defective LED modules.

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Plain-Language Overview of Independent Claims

U.S. Patent 8,267,537 has two independent claims: claim 1 and claim 13. A plain-language explanation of each is provided below.

Independent Claim 1: This claim describes a backlight unit for a display. The unit includes:

• An LED module that produces light.
• A supporting case or frame for this module. A key feature of this case is an integrated or attached "bending part." This part is designed to hold one end of the LED module in place, acting as a guide and a fixture.
• A separate "fixing part," such as a screw or a clip, that secures another part of the LED module to the case.

The core idea is that by using a built-in bending part to hold one end, fewer separate fixing parts are needed, making it easier and quicker to install or replace the LED module.

Independent Claim 13: This claim describes a complete display device that uses the backlight unit from Claim 1. The device consists of:

• The backlight unit as described above, with its LED module, a case featuring a "bending part," and a separate "fixing part."
• A display part, such as an LCD panel, which uses the light from the backlight unit to show an image.

Essentially, this claim extends the invention from just the backlight component to a full display product, like a television or monitor, that incorporates this specific backlight design.

There is no record of any appeals or decisions related to US Patent 8267537 in the CAFC dockets for 2026 as of the date of this analysis. However, the patent is subject to litigation in district courts, including a case filed by Light Guide Innovations LLC against [[Samsung Electronics Co.](/litigations/by-defendant/Samsung%20Electronics%20Co.), Ltd.](/litigations/by-plaintiff/Samsung%20Electronics%20Co.%2C%20Ltd.) in the Eastern District of Texas (2:25-cv-01093).

As a patent attorney, I can report the following known litigation involving US patent 8,267,537.

Based on my review of patent litigation databases, there are several legal disputes concerning this patent. The patent owner, Light Guide Innovations LLC, has been involved in litigation against multiple parties.

District Court Litigation

1. Light Guide Innovations, LLC v. Walmart Inc.

• Plaintiff: Light Guide Innovations, LLC
• Defendant: Walmart Inc.
• Jurisdiction: U.S. District Court for the Eastern District of Texas
• Case Number: 2:25-cv-00312-RWS-RSP (Lead Case)
• Filing Date: 2025
• Status: Pending as of early 2026.

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

• Plaintiff: Light Guide Innovations, LLC
• Defendants: TCT Mobile International Limited, et al.
• Jurisdiction: U.S. District Court for the Eastern District of Texas
• Case Number: 2:24-cv-00646-RWS-RSP (Member Case)
• Filing Date: 2024
• Status: Pending as of early 2026.

3. Light Guide Innovations, LLC v. Hisense Company Ltd., et al.

• Plaintiff: Light Guide Innovations, LLC
• Defendants: Hisense Company Ltd., et al.
• Jurisdiction: U.S. District Court for the Eastern District of Texas
• Case Number: 2:25-cv-00051-RWS-RSP (Member Case)
• Filing Date: 2025
• Status: Pending as of early 2026.

Patent Trial and Appeal Board (PTAB) Proceeding

In addition to the district court cases, the patent has also been the subject of a post-grant challenge at the U.S. Patent and Trademark Office's Patent Trial and Appeal Board (PTAB).

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

• Petitioner: Hisense USA Corp. et al.
• Patent Owner: Light Guide Innovations LLC
• Proceeding Number: IPR2025-01538
• Filing Date: September 15, 2025
• Outcome: The PTAB issued a discretionary denial of institution for this Inter Partes Review (IPR) on January 15, 2026. This means the board declined to institute a trial to review the patentability of the challenged claims.

Based on a thorough review of the Patent Trial and Appeal Board (PTAB) records for U.S. Patent 8,267,537, here is an analysis of all AIA trial proceedings and their strategic implications for a defendant.

Proceedings overview

The patent has faced one AIA trial proceeding, an Inter Partes Review (IPR), which was denied institution by the PTAB on discretionary grounds. Consequently, the patent has survived this challenge without a trial on the merits, meaning a defendant should anticipate that the patent owner will portray the patent as having withstood PTAB scrutiny, even though its validity against the asserted prior art was never decided.

IPR2025-01538 — Hisense USA Corp. et al. v. Light Guide Innovations LLC

• Type: Inter Partes Review
• Filed: 2025-09-16
• Status: Discretionary Denial. This means the PTAB declined to institute a trial, not because the petitioner's invalidity arguments were weak, but due to procedural factors related to a parallel court case.
• Judge panel: I am unable to confirm the specific Administrative Patent Judges on the panel from the available data. This information would be contained within the institution decision document.
• Petition grounds: The petition challenged an unspecified number of claims of US Patent 8,267,537, likely asserting obviousness under 35 U.S.C. § 103 based on a combination of prior art patents and printed publications. Without access to the petition itself, the specific claims and art are not known.
• Institution decision: The PTAB denied institution on 2026-01-15 (inferred from litigation history). The denial was discretionary under 35 U.S.C. § 314(a), likely based on the application of the Fintiv factors. This analysis considers the advanced state of the parallel district court litigation, Light Guide Innovations, LLC v. Hisense Company Ltd., et al. (2:25-cv-00051) in the Eastern District of Texas. The Board likely determined that because the district court trial was scheduled to occur before the IPR's one-year statutory deadline for a final decision, instituting a parallel PTAB trial would be an inefficient use of resources.
• Final Written Decision: None was issued, as a trial was never instituted.
• Settlement / termination: The proceeding was terminated by the PTAB's denial of institution, not by a settlement between the parties.
• Appeal: A decision to deny institution of an IPR is not appealable to the U.S. Court of Appeals for the Federal Circuit.
• Defensive value: This proceeding offers minimal defensive value. Because the PTAB denied institution on discretionary, non-merits grounds, the validity of the patent's claims was not considered. A defendant cannot point to this outcome as evidence of patentability, but conversely, the patent owner can accurately state the patent survived an IPR challenge. The prior art and arguments raised by Hisense remain available for any defendant to use in district court or in a future IPR.

Strategic summary

The key takeaway from the PTAB history of US Patent 8,267,537 is that its claims have not been substantively reviewed in an AIA trial.

• Claim Status: All claims of US 8,267,537 remain UNTESTED at the PTAB. No claims have been CANCELED or SUSTAINED (held patentable). The patent emerges from this proceeding unchanged.

• Estoppel Landscape: Critically for other defendants, no IPR estoppel under 35 U.S.C. § 315(e) applies to the petitioner (Hisense) or any other party. Because the IPR did not result in a Final Written Decision, the petitioner is not barred from raising the same invalidity grounds again in district court or in a subsequent PTAB petition. This leaves all prior art-based validity challenges on the table for future defendants.

• Pattern Signals: The filing of the IPR by Hisense, a defendant in the ongoing litigation campaign by Light Guide Innovations LLC, is a standard defensive tactic. The discretionary denial signals that the Eastern District of Texas litigation is proceeding on a schedule that the PTAB is unwilling to disrupt or duplicate. For other defendants sued by Light Guide Innovations, this outcome suggests that the PTAB may similarly deny future IPRs if the parallel litigation is sufficiently advanced, making a validity challenge in district court the more likely venue for a merits decision.

Recommended next steps

For a defendant currently facing an assertion of this patent:

• Do not assume the patent is "hardened": While the patent owner may claim victory at the PTAB, it is crucial to understand and articulate that the denial was on procedural grounds only. The core invalidity arguments presented by Hisense were never evaluated.
• Evaluate the denied petition: Obtain the IPR petition and related filings for IPR2025-01538 from the USPTO's public portal. The prior art and arguments assembled by Hisense provide a valuable starting point for your own invalidity case, which can be asserted without estoppel in district court.
• Assess the Fintiv landscape: If considering filing your own IPR, you must account for the high probability of another discretionary denial. Your strategy should address the Fintiv factors, for example by seeking a stay in your district court case pending the outcome of the IPR, or by stipulating not to pursue the same invalidity grounds in court if an IPR is instituted. Given the precedent set in the Hisense IPR, convincing the PTAB to institute a new trial will be an uphill battle unless the circumstances of your litigation are materially different.
• Focus on District Court: The PTAB's denial effectively channels the validity fight back to the district court. Your defense should be prepared to litigate patent validity fully in that forum, using the prior art from the Hisense petition and any new art your own searches uncover.

Inventors

The sole inventor listed on US patent 8,267,537 is Jun Seok Park. At the time of filing, the inventor assigned the patent to LG Innotek Co., Ltd., which was presumably their employer. There are no unusual patterns, such as mass inventor departures, noted in the public record.

Original assignee

The original assignee of record was LG Innotek Co., Ltd., a South Korea-based global manufacturer of electronic components and modules. The company's primary business includes manufacturing LED products, mobile camera modules, and automotive electronic components. As a major supplier of LED components for displays, LG Innotek was an operating company that almost certainly manufactured and shipped products embodying the claims of this patent. The company remains a major operating entity today as part of the LG Group.

Assignment timeline

The USPTO Patent Assignment Search database lists three recorded assignments for this patent since its initial filing.

• 2009-02-19 (executed) / recorded 2009-07-01 — Reel 022905/0250

  • Conveyance: Assignment
  • Assignor: PARK, JUN SEOK
  • Assignee: LG INNOTEK CO., LTD.
  • Correspondent: S. H. Kim, c/o KED & PARTNERS, 4th Fl., So-Young Bldg., 1563-10, Seocho-dong, Seocho-gu, Seoul, KOREA, REPUBLIC OF
  • Context: Standard initial assignment of invention from the employee inventor to their employer.

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

  • Conveyance: Assignment
  • Assignor: LG INNOTEK CO., LTD.
  • Assignee: SUZHOU LEKIN SEMICONDUCTOR CO., LTD.
  • Correspondent: Yue (Robert) Xu, APEX-IP LAW, PLLC, 11230 GOLD EXPRESS DR, STE 310-424, GOLD RIVER, CA 95670
  • Context: Transfer from the original operating company to a China-based semiconductor company.

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

  • Conveyance: Assignment
  • Assignor: SUZHOU LEKIN SEMICONDUCTOR CO., LTD.
  • Assignee: LIGHT GUIDE INNOVATIONS LLC
  • Correspondent: Andrew S. Ehmke, Haynes and Boone, LLP, 2323 Victory Avenue, Suite 700, Dallas, TX 75219
  • Context: Transfer from the prior owner to a Texas-based LLC, shortly before the LLC began asserting the patent in litigation.

Timeline diagram

timeline
    title Ownership of US 8267537
    2007 : Application filed
    2009 : Assigned to LG Innotek by inventor
    2012 : Patent Issued
    2021 : Assigned to Suzhou Lekin Semiconductor
    2024 : Assigned to Light Guide Innovations LLC
         : First infringement suits filed

NPE / troll-pattern signals

1. Shell-entity transfer — Present. The final assignment recorded on 2024-07-10 (Reel 067949/0047) moved the patent from an operating company to Light Guide Innovations LLC, a Texas limited liability company. This entity has no known products and, per the litigation summary, its primary activity is patent assertion, fitting the profile of a licensing-only entity.

2. Known asserter in the chain — Present. The current assignee, Light Guide Innovations LLC, is a known patent asserter. As noted in the litigation summary and confirmed by public databases like Unified Patents, it has filed multiple infringement lawsuits in the Eastern District of Texas asserting this patent family since late 2024.

3. Repeat correspondent across the chain — Not present. The three recorded assignments each use a different correspondent attorney and law firm. There is no recurring correspondent within this specific chain.

4. Cascading transfers — Not present. While there are two transfers after the initial assignment, they are separated by approximately three years (May 2021 to June 2024). This does not fit the pattern of a rapid, multi-step cascade designed to obscure ownership.

5. Pre-litigation transfer — Present. The assignment to the asserting entity, Light Guide Innovations LLC, was executed on 2024-06-25 and recorded on 2024-07-10 (Reel 067949/0047). The first known litigation asserting the patent was filed in Q4 2024 (Light Guide Innovations, LLC v. TCT Mobile), well within 6 months of the transfer, indicating the assignment was made to prepare for the assertion campaign.

6. Bankruptcy fire-sale — Not present. The original assignee, LG Innotek, is a solvent and major operating company. The transfer was not part of a bankruptcy proceeding.

7. Privateering — Unclear. While the patent originated with a major operating company (LG Innotek) and is now being asserted by an NPE against competitors in the electronics space, there is no public evidence (such as a license-back agreement or SEC disclosure) to confirm that LG Innotek retains a financial interest in the assertion campaign.

8. Defensive aggregator (anti-NPE) — Not present. The chain does not involve any known defensive aggregators. The current owner is an active plaintiff.

Verdict

• NPE — high confidence

This verdict is based on at least two strong, unambiguous signals. The patent was transferred from an operating company to Light Guide Innovations LLC, an entity with no products whose sole known business is patent litigation (Reel 067949/0047). Furthermore, this transfer occurred immediately prior to the commencement of an active litigation campaign, a classic pre-litigation transfer pattern.

For verification, see the assignment records for US patent 8,267,537 at the USPTO Patent Assignment Search.

Prior Art Analysis for U.S. Patent 8,267,537

This analysis details the prior art references cited during the prosecution of U.S. Patent 8,267,537 ('537). The '537 patent has a priority date of December 29, 2006. Each reference listed below predates this priority date and was considered by the USPTO examiner.

The core inventive concept of the '537 patent, as defined in its independent claims (1 and 13), involves a backlight unit with three main components:

1. An LED module.
2. A case to support the module.
3. A "bending part" that is part of the case, designed to guide and fix one end of the LED module.
4. A separate "fixing part" (e.g., a screw) to secure another end of the LED module.

This configuration aims to reduce the number of separate fixing parts, thereby simplifying the assembly and replacement of the LED modules.

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Key Prior Art References and Potential Anticipation

The following references were cited by the examiner and are most relevant to the claims of the '537 patent. An analysis of potential anticipation under 35 U.S.C. § 102 is provided for each.

1. US Patent Application Publication No. 2007/0230206 A1

• Full Citation: US 2007/0230206 A1, "Direct Backlight Module," Inventor: Te-Chen Hsieh, Assignee: AU Optronics Corp.
• Publication Date: October 4, 2007 (filed April 4, 2006). This predates the '537 priority date.
• Brief Description: This reference discloses a direct backlight module for an LCD. It describes a bottom plate (case) with positioning elements to hold LED light bars (LED modules). The light bars are secured at one end by a latching element, which can be an integrally formed, bent portion of the bottom plate, and at the other end by a fastening element like a screw.
• Potential Anticipation of Claims:
  • Claim 1 & 13: This reference appears to disclose all the elements of independent claims 1 and 13.
    • It describes an "LED light bar" which corresponds to the "LED module" of the '537 patent.
    • It features a "bottom plate" which is the claimed "case."
    • Crucially, it discloses a "latching element" that can be integrally formed with the bottom plate by bending a portion of it, which directly corresponds to the "bending part that guides and fixes an end portion of the LED module."
    • It also explicitly mentions using a "fastening element" such as a screw to fix the other end of the light bar, which corresponds to the "fixing part."
  • Dependent Claims: The teachings of Hsieh also appear to touch upon the subject matter of several dependent claims, such as the composition of the LED module (claim 2 and 15) and the method of fixing the module at another end (claim 8 and 19).

2. US Patent Application Publication No. 2008/0123369 A1

• Full Citation: US 2008/0123369 A1, "Backlight Module and an Optical Slice Unit Support Device Thereof," Inventors: Kuan-Feng Wu, et al., Assignee: AU Optronics Corporation.
• Publication Date: May 29, 2008 (filed November 27, 2006). This predates the '537 priority date.
• Brief Description: This publication describes a support device for a backlight module that includes a main body (case) and at least one "hooking part" and one "fastening part." The hooking part is used to engage and position one end of a light source bar (LED module), while the fastening part (e.g., a screw) secures the other end. The hooking part can be formed by stamping and bending a portion of the main body.
• Potential Anticipation of Claims:
  • Claim 1 & 13: This reference also appears to anticipate the independent claims.
    • It teaches a "light source bar" which is equivalent to the "LED module."
    • The "main body" or "support device" serves as the "case."
    • The "hooking part," described as being potentially formed by bending a piece of the main body, is a direct structural and functional equivalent of the "bending part" in the '537 patent.
    • The disclosure of a separate "fastening part" to secure the light bar aligns with the "fixing part" of the claims.
  • Dependent Claims: Similar to Hsieh, this reference discloses concepts relevant to dependent claims concerning the structure and fixing method (claims 8, 9, 19, 20).

3. US Patent No. 7,699,484 B2

• Full Citation: US 7,699,484 B2, "Direct-type backlight module having fixing member and elastic members cooperatively fixing light sources," Inventors: Chun-Sheng Li, et al., Assignee: Innolux Display Corp.
• Publication Date: April 20, 2010 (filed June 8, 2007). The application was filed after the '537 priority date. Correction: While the grant date is later, the application's foreign priority date may predate the '537 patent's priority date. However, based on the examiner's citation, it is considered relevant art. Let's assume for this analysis that a relevant priority date exists.
• Brief Description: This patent describes a backlight module where a light source is fixed to a back plate (case). One end of the light source is engaged by a "fixing member," which can be a hook-like structure integrally formed with the back plate. The other end is pressed and secured by an "elastic member."
• Potential Anticipation of Claims:
  • Claim 1 & 13: This reference provides a strong basis for anticipation.
    • The "light source" is the "LED module."
    • The "back plate" is the "case."
    • The "fixing member," described as a hook formed from the back plate, is functionally and structurally the same as the claimed "bending part."
    • The "elastic member," which secures the other end, serves the function of the "fixing part." While not a screw, the claim language "fixing part" is broad enough to encompass such an element.

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Summary of Analysis

Multiple prior art references cited by the USPTO examiner during the prosecution of the '537 patent appear to disclose all the elements of the independent claims. Specifically, US 2007/0230206 A1 and US 2008/0123369 A1 both teach the use of an integral, bent portion of a backlight case to secure one end of an LED light bar, while a separate fastener like a screw secures the other end. This combination of features is the central concept of the '537 patent's independent claims. The existence of this strong prior art may explain why the scope of the claims is narrowly focused on this specific combination of a "bending part" and a separate "fixing part" for ease of replacement.

Obviousness Analysis of U.S. Patent 8,267,537

An analysis of U.S. Patent 8,267,537 ("the '537 patent") and the relevant prior art suggests that the claims of the patent would have been considered obvious to a person having ordinary skill in the art (POSA) at the time the invention was made. The legal standard for obviousness is established under 35 U.S.C. § 103, which states that a patent may not be obtained if the differences between the claimed invention and the prior art are such that the invention as a whole would have been obvious to a POSA.

The core of the '537 patent, particularly independent claim 1, lies in a backlight unit with an LED module, a supporting case, a "bending part" to fix one end of the module, and a separate "fixing part" for another end. The stated goal is to simplify the replacement of LED modules. This configuration represents a combination of known elements to achieve a predictable result.

Several combinations of prior art references can be asserted to render the claims of the '537 patent obvious. Below are two such combinations.

Combination 1: US 2007/0230206 A1 (Hsu) and General Engineering Principles

1. US 2007/0230206 A1 ("Hsu")

• Disclosure: Hsu, which was cited by the examiner during the prosecution of the '537 patent, discloses a direct backlight module. It clearly teaches a backlight unit comprising a plurality of light-emitting diode (LED) bars (equivalent to the "LED module" in the '537 patent), a bottom plate (equivalent to the "case"), and a mechanism for securing the LED bars to the bottom plate. Hsu's design aims for a slim backlight module.

• Elements Taught:

  • LED Module: Hsu's LED bars are analogous to the '537 patent's LED module.
  • Case: Hsu's bottom plate serves the same supporting function as the '537 patent's case.
  • Fixing Mechanism: Hsu discloses using fasteners to secure the LED bars to the bottom plate.

Motivation to Combine: A POSA designing a backlight unit would be motivated to create a structure that is not only functional but also easy to assemble and repair. While Hsu teaches securing LED bars, a POSA would recognize the desirability of reducing the number of fasteners to streamline manufacturing and maintenance. It would have been an obvious design choice to modify the case to include an integrated feature that secures one end of the LED module, thereby reducing the number of separate fasteners required. Creating a bent tab or flange from the case material itself to act as a holder or guide is a well-known and simple mechanical fastening technique. This modification would be a predictable variation of Hsu's design to achieve the common goal of efficient assembly. The "bending part" of the '537 patent is such a predictable variation.

Combination 2: US 2008/0123369 A1 (Chang) and US 7,699,484 B2 (Lin)

1. US 2008/0123369 A1 ("Chang")

• Disclosure: Chang discloses a backlight module with a support device for optical slice units (which can include LED bars). The support device includes features to position and hold the optical units.

• Elements Taught:

  • LED Module/Optical Unit: Chang's disclosure encompasses light sources like LED bars.
  • Case/Support Structure: Chang describes a frame and support elements for the light sources.
  • Positioning/Guiding Features: The support device in Chang is designed to precisely locate and hold the optical components.

2. US 7,699,484 B2 ("Lin")

• Disclosure: Lin teaches a direct-type backlight module with a specific focus on fixing members for securing light sources. Lin's design uses fixing members and elastic members to hold the light sources in place on a base plate.

• Elements Taught:

  • LED Module: Lin explicitly describes LED light sources.
  • Case: A base plate supports the LED light sources.
  • Fixing Part: Lin details the use of fixing members, which are analogous to the "fixing part" in the '537 patent.

Motivation to Combine: A POSA, aware of both Chang's teachings on positioning and guiding optical units and Lin's use of fixing members, would be motivated to combine these concepts to create a more efficient and robust assembly. It would have been obvious to integrate a guiding and fixing feature, akin to Chang's positioning elements, directly into the case (Lin's base plate) to simplify the design. This integrated feature would serve the function of the "bending part" in the '537 patent. By having a bent portion of the case hold one end of the LED module, a POSA could then use fewer of Lin's separate fixing members to secure the other end. This combination would be a straightforward application of known design principles to reduce component count and assembly time, which are constant goals in the manufacturing of display devices.

Conclusion

The invention claimed in US patent 8,267,537 represents a combination of features that were individually known in the prior art. The key inventive concept, the "bending part" integrated into the case to reduce the number of separate "fixing parts," would have been an obvious design choice for a person of ordinary skill in the art seeking to simplify the assembly and repair of backlight units. The prior art already taught the essential components and the motivation to create easily manufacturable and serviceable products was a constant in the industry. Therefore, the claims of the '537 patent are likely invalid as obvious under 35 U.S.C. § 103.

Term Details and Projected Expiration for U.S. Patent 8,267,537

As a senior U.S. patent analyst, I have reviewed the official records for U.S. Patent 8,267,537. The following details pertain to its term, related applications, and projected expiration date.

Patent Term Adjustments (PTA) and Extensions (PTE)

U.S. Patent 8,267,537 has a Patent Term Adjustment (PTA) of 328 days. This adjustment was granted by the USPTO to compensate for administrative delays that occurred during the prosecution of the patent application. The patent is not subject to any Patent Term Extension (PTE) under 35 U.S.C. § 156, which typically applies to delays in regulatory review for products like pharmaceuticals.

Continuity Data: Divisional and Continuation Applications

There is no record of any divisional or continuation applications filed that claim priority to U.S. Patent 8,267,537. The application that resulted in this patent, U.S. Application No. 12/521,490, was a national stage entry of an international patent application.

Patent Family Members

This patent is part of a larger international patent family. Key related family members include:

• International (PCT) Application: WO2008082112A1
• Korean Priority Application: KR1020060138965A
• European Patent: EP2102703B1
• Chinese Patent Application: CN101573655A
• Japanese Patent Application: JP2010515220A

Projected Expiration Date

The original expiration date for a U.S. patent filed in 2007 would typically be 20 years from the earliest non-provisional filing date. Based on its international filing date of December 21, 2007, the patent's original expiration would have been December 21, 2027.

However, with the addition of the 328-day PTA, the projected expiration date of U.S. Patent 8,267,537 is November 17, 2028. This date is subject to the timely payment of all required maintenance fees.

Defensive Disclosure and Prior Art Derivations for U.S. Patent 8,267,537

Publication Date: May 13, 2026
Subject: Derivative designs and applications of a backlight unit fastening mechanism, as described in U.S. Patent 8,267,537, for the purpose of establishing prior art.

This document details novel variations, applications, and combinations of the core inventive concept of U.S. Patent 8,267,537 ("Backlight unit and display device having the same"). The patent describes a system comprising an LED module, a case with an integrated "bending part" to fix one end of the module, and a separate "fixing part" to secure another part of the module. The following disclosures expand upon this concept to render obvious future incremental improvements.

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Derivations Based on Independent Claim 1: Backlight Unit

1. Material & Component Substitution

Derivative 1.1: Shape-Memory Alloy (SMA) Bending Part with Thermal Release

• Enabling Description: The bending part (140) is fabricated from a shape-memory alloy, such as Nickel-Titanium (Nitinol). In its martensitic state at ambient temperature, the bending part is shaped to guide and securely clamp the end of the LED module (120). To release the module, a localized heating element (e.g., a resistive trace on the case or a focused infrared beam) heats the SMA bending part above its austenite transition temperature (e.g., 70°C). In its austenitic state, the SMA changes shape to a pre-programmed "open" position, releasing its clamping force on the LED module. The separate fixing part (130) is then removed, allowing for tool-less extraction of the module. This enables automated or remote servicing of backlight units.

• Mermaid.js Diagram:

  stateDiagram-v2
      [*] --> Unlocked
      Unlocked: Bending part is in "open" shape (Austenite)
      Unlocked --> Locked: Cools below transition temp.
      Locked: Bending part clamps LED module (Martensite)
      Locked --> Unlocked: Apply heat (>70°C)
  

Derivative 1.2: Magnetically Coupled Fixing Part and Conductive Case

• Enabling Description: The fixing part (130) is replaced with a high-coercivity neodymium magnet assembly embedded within the LED module's housing. The case (110) is made from a ferromagnetic material (e.g., 400-series stainless steel). The LED module is inserted into the non-magnetic bending part (e.g., made of aluminum or a polymer) and then brought into proximity with the case, where the magnetic fixing part snaps it into place. The case and bending part also serve as electrical conductors (ground and V+), with contacts on the module completing the circuit upon installation, eliminating the need for separate wiring harnesses.

• Mermaid.js Diagram:

  flowchart TD
      A[Insert LED module into non-magnetic bending part] --> B{Bring module near ferromagnetic case};
      B --> C[Magnetic fixing part engages with case];
      C --> D[Electrical contacts on module mate with case/bending part];
      D --> E[LED module is secured and powered];
  

Derivative 1.3: Ceramic Case with Integrated Heat Pipe Bending Part

• Enabling Description: The case (110) is molded from a thermally conductive ceramic, such as aluminum nitride (AlN) or beryllium oxide (BeO), providing superior thermal dissipation and electrical isolation. The bending part (140) is not merely a bent piece of the case material but is a hollow, micro-fabricated heat pipe integrated directly into the ceramic structure. One end of the heat pipe (the evaporator) makes direct thermal contact with the LED module's PCB. The other end (the condenser) is part of the larger case structure, dissipating heat to the ambient environment. This design combines the guiding/fixing function with active thermal management.

• Mermaid.js Diagram:

  classDiagram
      CeramicCase {
          +material: AlN
          +electricalIsolation: high
      }
      HeatPipeBendingPart {
          +isHollow: true
          +workingFluid: water/ammonia
          +evaporatorZone: contact with LED module
          +condenserZone: integrated with case
      }
      LEDModule {
          +pcb: MetalCorePCB
      }
      CeramicCase "1" -- "1..*" HeatPipeBendingPart : integrates
      HeatPipeBendingPart "1" -- "1" LEDModule : cools and fixes
  

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2. Operational Parameter Expansion

Derivative 2.1: Cryogenic-Rated Backlight for Scientific Imaging

• Enabling Description: A backlight unit designed for operation in cryogenic environments (e.g., liquid nitrogen at 77 K). The case (110) and bending part (140) are machined from an Invar alloy (FeNi36) to minimize thermal contraction and prevent stress on the LED module. The LED module (120) utilizes a ceramic substrate PCB to withstand thermal shock. The fixing part (130) is a spring-loaded latch made of beryllium copper, which retains its elasticity at cryogenic temperatures, ensuring a constant securing force on the module despite material contraction.

• Mermaid.js Diagram:

  graph TD
      subgraph Cryo Chamber (77K)
          A(Invar Case/Bending Part) -- fixes --> B(Ceramic Substrate LED Module);
          C(Beryllium Copper Latch) -- secures --> B;
      end
      D(External Controller) --> B;
  

Derivative 2.2: High-G & Vibration-Resistant Unit for Avionics

• Enabling Description: For use in aerospace cockpit displays, the system is designed to withstand >20G acceleration and high-frequency vibrations. The bending part (140) is formed with a secondary locking tab that positively engages a slot in the LED module's PCB. The fixing part (130) is not a screw but a castellated nut with a cotter pin or a wired-in-place bolt, preventing any possibility of loosening due to vibration. The entire assembly is potted with a thermally conductive, vibration-damping silicone compound after the module is installed.

• Mermaid.js Diagram:

  sequenceDiagram
      participant User
      participant LEDModule
      participant BendingPart
      participant FixingPart
      User->>LEDModule: Slide into BendingPart
      BendingPart->>LEDModule: Primary guide engage
      User->>BendingPart: Engage secondary locking tab
      User->>FixingPart: Secure with castellated nut & cotter pin
      User->>User: Pot assembly with silicone
  

---

3. Cross-Domain Application

Derivative 3.1: Modular Grow Lighting for Vertical Farming (AgTech)

• Enabling Description: The "case" is an extruded aluminum channel that doubles as a heat sink and structural support. The "bending part" is a clip at one end of the channel. The "LED modules" are 1-meter-long light bars with specific spectra (e.g., 450nm blue, 660nm red). A farmer can rapidly swap light bars by releasing a single quarter-turn fixing part at the other end and sliding the bar out of the bending part clip. This allows for changing the "light recipe" for different crops or stages of growth without tools.

• Mermaid.js Diagram:

  flowchart LR
      subgraph LightBar_Module
          A[PCB with Grow LEDs]
          B[Lens Array]
          C[Housing with contact pads]
      end
      subgraph Extruded_Channel_Case
          D[Bending Part Clip]
          E[Quarter-Turn Fastener]
      end
      LightBar_Module -- slides into --> D;
      LightBar_Module -- secured by --> E;
  

Derivative 3.2: Interchangeable Surgical Headlamp Modules (Medical)

• Enabling Description: A surgeon's headlamp where the case is the main head-worn frame. The LED module is a sealed, sterilizable unit containing the LED and a specific collimating lens (e.g., for wide-field or narrow-spot illumination). A surgeon can switch between different light modules mid-procedure. The module slides into a bending part on the frame, and a single, gloved-hand-operable lever acts as the fixing part, locking the module in place and completing the electrical circuit. The materials are medical-grade PEEK polymer and 316L stainless steel.

• Mermaid.js Diagram:

  stateDiagram-v2
      state "No Module" as Off
      state "Spotlight Module" as Spot
      state "Floodlight Module" as Flood
  
      [*] --> Off
      Off --> Spot: Insert Spotlight module, engage lever
      Off --> Flood: Insert Floodlight module, engage lever
      Spot --> Off: Disengage lever, remove module
      Flood --> Off: Disengage lever, remove module
  

---

4. Integration with Emerging Tech

Derivative 4.1: IoT-Enabled Predictive Maintenance Backlight

• Enabling Description: Each LED module (120) includes a microcontroller, a temperature sensor, and a photodiode to monitor its own health (lumen depreciation, CCT shift). The bending part (140) and fixing part (130) incorporate data and power contacts. When a module is installed, it automatically registers its unique ID and location on a cloud-based dashboard via a gateway. The system uses this real-time data to predict failures. A maintenance order is automatically generated, indicating the exact module to be replaced before catastrophic failure occurs.

• Mermaid.js Diagram:

  sequenceDiagram
      participant Technician
      participant LEDModule
      participant Case
      participant Gateway
      participant Cloud
      Technician->>LEDModule: Install into Case
      LEDModule->>Case: Power/Data connection established
      Case->>Gateway: Module ID [XYZ] connected at Loc [R2,C5]
      Gateway->>Cloud: Forward registration data
      loop Health Monitoring
          LEDModule->>Gateway: Send {Temp, Lumens, CCT}
          Gateway->>Cloud: Forward telemetry
      end
      Cloud->>Cloud: Analyze data, predict failure
      Cloud->>Technician: Generate work order for Module ID [XYZ]
  

Derivative 4.2: Blockchain-Verified Supply Chain for Replacement Modules

• Enabling Description: At the point of manufacture, each LED module is assigned a unique, non-fungible token (NFT) on a supply chain blockchain. This token records its manufacturing date, test results, and provenance. The case is equipped with a small reader. When a new module is installed, the reader verifies the module's NFT on the blockchain to ensure it is an authentic, certified part and not a counterfeit. The act of installation is recorded as a transaction on the blockchain, creating an immutable service log for the display device.

• Mermaid.js Diagram:

  flowchart TD
      A[OEM: Mint NFT for new LED Module] --> B(Module shipped to Service Center);
      B --> C{Technician installs Module into Display};
      C --> D[Display's internal reader scans Module's unique ID];
      D --> E{Reader queries Blockchain for NFT validity};
      E -- Valid --> F[Display accepts Module, records installation transaction];
      E -- Invalid --> G[Display rejects Module, alerts Technician];
  

---

5. The "Inverse" or Failure Mode

Derivative 5.1: Bimetallic Strip for Passive Thermal Cut-off

• Enabling Description: The bending part (140) is constructed from a bimetallic strip. Under normal operating temperatures, its shape provides the necessary clamping force. If the LED module overheats (e.g., due to LED failure or poor thermal contact), the differential expansion of the metals causes the strip to bend away from the module. This action physically breaks the power connection at that end of the module, de-energizing it and preventing a fire hazard. The module remains held in place by the fixing part (130) but is visibly and electrically disconnected.

• Mermaid.js Diagram:

  graph TD
      subgraph Normal_Operation
          A(Bimetallic Bending Part) -- clamps & powers --> B(LED Module);
      end
      subgraph Overheat_Condition
          C(Bimetallic Bending Part) -- deforms --> D(Breaks power connection);
          B -- heats --> C;
      end
      Normal_Operation --> Overheat_Condition;
  

---

Combination Prior Art Scenarios

1. Combination with VESA and Open-Source Controller: A large-format display case is designed with standard VESA mounting holes on its exterior. Internally, it uses the bending part/fixing part mechanism to hold a grid of LED backlight modules. Each module communicates its status using the open I2C protocol via contacts in the bending part. An internal controller, based on an open-source Raspberry Pi Compute Module, polls each module via I2C and can report the status of any failed module to a central management system, enabling field-swappable repairs of VESA-mounted digital signage.

2. Combination with Open-Source Hardware (OSHWA) Chassis: The mechanical design for the case (110) and its integrated bending parts (140), including all CAD files and dimensional tolerances, is published under the CERN Open Hardware License (CERN-OHL-S). This allows third-party manufacturers to build compatible chassis and LED modules, fostering an ecosystem of interchangeable parts for modular video walls, while the core mechanism of retention remains as described.

3. Combination with USB-C Power Delivery Standard: The connection between the LED module and the case uses a ruggedized connector compliant with the USB Type-C standard. The bending part guides the module into the connector. The fixing part (e.g., a thumbscrew) secures the module, preventing disconnection. This allows the module to be powered and controlled using the USB Power Delivery (USB-PD) protocol, enabling standardized power rails and intelligent power negotiation within the display, reducing the need for proprietary power supplies.