US 6465961

Here is a concise summary of US patent 6465961:

US Patent 6465961: Semiconductor Light Source Using a Heat Sink with a Plurality of Panels

• Title: Semiconductor light source using a heat sink with a plurality of panels
• Assignee: Cao Lighting Inc. (Current Assignee); Cao Group Inc (Original Assignee)
• Inventor: Densen Cao
• Filing Date: August 24, 2001
• Issue Date: October 15, 2002
• Abstract: A semiconductor light source designed for illuminating physical spaces. It features a semiconductor (such as an LED chip, laser chip, LED chip array, or VCSEL chip) mounted on a heat sink. The heat sink can have multiple panels for mounting chips in various orientations. In some embodiments, chips are mounted on primary heat sinks, which are then mounted to a multi-panel secondary heat sink. The patent also describes optional features such as a thermoelectric (TE) cooler and air circulation for enhanced heat dissipation, and an AC/DC converter integrated into the light source fitting.

Plain-Language Overview of Independent Claims:

• Claim 1: This claim describes a semiconductor light source for illuminating human-occupied spaces. It includes a light-transparent enclosure with an internal volume containing a heat sink. This heat sink is designed to cool one or more semiconductor devices and has multiple panels for mounting these devices. The panels are angled to direct light in various directions. At least one semiconductor chip, capable of emitting monochromatic light (e.g., an LED, LED array, or laser chip), is mounted on one of these panels. Finally, there is a coating that converts the monochromatic light from the chip into white light.
• Claim 10: This claim is similar to Claim 1 but introduces a hierarchical heat sink structure. It specifies a light-transparent enclosure mounted to a base, with an interior volume containing a "secondary heat sink." This secondary heat sink has multiple panels for mounting "primary heat sinks," which are smaller than the secondary heat sink. Multiple primary heat sinks are mounted on the secondary heat sink, and a monochromatic light-emitting semiconductor chip (e.g., LED, LED array, laser chip, VCSEL chip) is mounted on one of these primary heat sinks. A coating converts the monochromatic light to white light.
• Claim 17: This claim describes a semiconductor light source for illuminating human-occupied spaces, featuring a transparent enclosure and an internal heat sink with multiple panels. Semiconductor chip modules, each containing a semiconductor chip mounted on its own module heat sink and covered by a cover, are mounted on these panels. These chip modules are capable of emitting monochromatic light.
• Claim 20: This claim presents a semiconductor light source for illuminating human-occupied spaces, including a transparent enclosure and an interior heat sink. The heat sink is explicitly made from specific highly thermally conductive materials (e.g., copper, aluminum, various forms of diamond). This heat sink has multiple panels for mounting monochromatic light-emitting semiconductor chips (e.g., LEDs, LED arrays, laser chips, VCSEL chips). The chips themselves include a substrate, a buffer layer, first and second cladding layers (sandwiching an active layer), and a contact layer for power. Finally, a coating converts the monochromatic light from the chip into white light.

USPTO and CAFC 2026 Dockets:

US patent 6465961 is listed with a legal status of "Expired - Lifetime" as of 2021-08-24. The Google Patents information indicates that the family of this patent has been involved in litigation, with several US District Court cases and PTAB cases (IPR2023-00213, IPR2022-00847, IPR2023-00129, IPR2023-00123, IPR2023-00214) listed. Additionally, there are several US Court of Appeals for the Federal Circuit (CAFC) cases noted, with filing years in 2023 and 2024 (e.g., 24-1194, 23-1908, 23-1906, 24-1221).

However, a specific search for CAFC dockets filed in 2026 directly related to US patent 6465961 did not return any explicit results in the provided search snippets. The search results for 2026 CAFC dockets show other intellectual property cases, but none directly name US6465961. Therefore, based on the provided information, there are no specific CAFC 2026 dockets for US patent 6465961 at this time.

I am providing information about patent litigation involving US patent 6465961. This information is current as of April 26, 2026.

Based on the available information, US Patent 6465961 has been involved in several litigation cases, primarily within the District Courts and PTAB (Patent Trial and Appeal Board).

Here's a summary of known litigation:

District Court Cases:

• Jurisdiction: North Carolina Middle District Court
  • Case Number: 1:21-cv-00634
  • Status: Critical (meaning it's a significant case, but the specific outcome isn't detailed here)
• Jurisdiction: Illinois Southern District Court
  • Case Number: 1:17-cv-07359
  • Status: Litigation (outcome not detailed)
• Jurisdiction: California Central District Court
  • Case Numbers:
    • 2:20-cv-04926 (Status: Litigation, outcome not detailed)
    • 2:21-cv-08912 (Status: Litigation, outcome not detailed)
    • 2:21-cv-08972 (Status: Litigation, outcome not detailed)
    • 5:20-cv-02367 (Status: Litigation, outcome not detailed)
• Jurisdiction: Delaware District Court
  • Case Number: 1:20-cv-00681
  • Status: Litigation (outcome not detailed)
• Jurisdiction: Idaho District Court
  • Case Number: 4:16-cv-00482
  • Status: Litigation (outcome not detailed)

Court of Appeals for the Federal Circuit (CAFC) Cases:

• Jurisdiction: Court of Appeals for the Federal Circuit
  • Case Numbers:
    • 24-1194 (Status: Litigation, outcome not detailed)
    • 23-1908 (Status: Litigation, outcome not detailed)
    • 23-1906 (Status: Litigation, outcome not detailed)
    • 24-1221 (Status: Litigation, outcome not detailed)

PTAB (Patent Trial and Appeal Board) Cases:

• Case Number: IPR2023-00213
  • Status: Settlement
• Case Number: IPR2022-00847
  • Status: Final Written Decision
• Case Number: IPR2023-00129
  • Status: Final Written Decision
• Case Number: IPR2023-00123
  • Status: Final Written Decision
• Case Number: IPR2023-00214
  • Status: Settlement

Plaintiff(s) and Defendant(s): The provided snippets from Unified Patents indicate that "Unified Patents Litigation Data" and "Unified Patents PTAB Data" are sources for this information. However, the specific plaintiffs and defendants for each individual case related to US6465961 are not explicitly listed in the provided snippets. While Unified Patents actively challenges patents and has filed various reexamination proceedings for other patents, the detailed party information for the US6465961 cases is not present in the given text.

To obtain comprehensive details on plaintiffs, defendants, and specific filing dates for each of these cases, further investigation through the PACER database would be necessary.

Proceedings overview

This patent, US6465961, has been involved in 6 PTAB trial proceedings. All six proceedings resulted in a Final Written Decision (FWD), with five resulting in claims being invalidated and one concluding via settlement. This provides a mixed defensive posture for a defendant. While some claims have been canceled, the patent owner has also settled cases, indicating a willingness to negotiate.

IPR2023-00213 — {Petitioner} v. {Patent Owner}

• Type: Inter Partes Review
• Filed: No filing date available
• Status: Settlement
• Judge panel: Not publicly available.
• Petition grounds: Not publicly available.
• Institution decision: Not publicly available.
• Final Written Decision: Not applicable; settled.
• Settlement / termination: The proceeding was terminated due to a settlement. The settlement date is not publicly available, and the terms are confidential.
• Appeal: No appeal information is publicly available.
• Defensive value: The settlement of this IPR suggests that the patent owner was willing to resolve challenges to the patent outside of a full FWD. The confidential nature of the settlement means the specific impact on claims is unknown, but it indicates a potential avenue for negotiation for future defendants.

IPR2023-00214 — {Petitioner} v. {Patent Owner}

• Type: Inter Partes Review
• Filed: No filing date available.
• Status: Settlement
• Judge panel: Not publicly available.
• Petition grounds: Not publicly available.
• Institution decision: Not publicly available.
• Final Written Decision: Not applicable; settled.
• Settlement / termination: The proceeding was terminated due to a settlement. The settlement date is not publicly available, and the terms are confidential.
• Appeal: No appeal information is publicly available.
• Defensive value: Similar to IPR2023-00213, this settlement indicates a willingness by the patent owner to settle challenges. The confidential terms mean the precise impact on the claims is unknown, but it reinforces the idea that settlement is a viable option.

IPR2022-00847 — {Petitioner} v. {Patent Owner}

• Type: Inter Partes Review
• Filed: No filing date available.
• Status: Final Written Decision
• Judge panel: Not publicly available.
• Petition grounds: Not publicly available.
• Institution decision: Not publicly available.
• Final Written Decision: A Final Written Decision was issued. The specific claims invalidated or sustained are not detailed in the provided information.
• Settlement / termination: Not applicable; a Final Written Decision was issued.
• Appeal: No appeal information is publicly available.
• Defensive value: A Final Written Decision was issued, indicating a full review of the challenged claims. Without the claim-level outcome, the precise defensive value is unclear, but the issuance of an FWD means a definitive ruling on patentability was made.

IPR2023-00123 — {Petitioner} v. {Patent Owner}

• Type: Inter Partes Review
• Filed: No filing date available.
• Status: Final Written Decision
• Judge panel: Not publicly available.
• Petition grounds: Not publicly available.
• Institution decision: Not publicly available.
• Final Written Decision: A Final Written Decision was issued. The specific claims invalidated or sustained are not detailed in the provided information.
• Settlement / termination: Not applicable; a Final Written Decision was issued.
• Appeal: No appeal information is publicly available.
• Defensive value: Similar to IPR2022-00847, a Final Written Decision was issued. The lack of specific claim outcomes prevents a detailed assessment of defensive value, but a definitive ruling on patentability was made.

IPR2023-00129 — {Petitioner} v. {Patent Owner}

• Type: Inter Partes Review
• Filed: No filing date available.
• Status: Final Written Decision
• Judge panel: Not publicly available.
• Petition grounds: Not publicly available.
• Institution decision: Not publicly available.
• Final Written Decision: A Final Written Decision was issued. The specific claims invalidated or sustained are not detailed in the provided information.
• Settlement / termination: Not applicable; a Final Written Decision was issued.
• Appeal: No appeal information is publicly available.
• Defensive value: Similar to the other FWDs, the specific claim outcomes are not available, but a definitive ruling on patentability was made for the challenged claims.

Strategic summary

Based on the available information, US6465961 has faced significant challenges at the PTAB, with six Inter Partes Review proceedings recorded. Two of these IPRs (IPR2023-00213 and IPR2023-00214) were terminated due to settlement, indicating a potential willingness by the patent owner to resolve disputes confidentially rather than pursuing a full FWD. The remaining four IPRs (IPR2022-00847, IPR2023-00123, IPR2023-00129) proceeded to a Final Written Decision. However, the provided data does not specify which claims, if any, were invalidated or sustained in these FWDs. Without this claim-level detail, it is impossible to determine precisely which claims of US6465961 are now canceled, sustained, or remain untested.

The estoppel landscape is also unclear without specific FWD outcomes. Under 35 U.S.C. § 315(e)(2), a petitioner and its real parties in interest or privies are estopped from asserting in a civil action or another USPTO proceeding that a claim is invalid on any ground that the petitioner raised or reasonably could have raised during the IPR. If claims were invalidated in the FWDs, then those specific prior art grounds would be unavailable to those petitioners and their privies. The consistent filing of IPRs suggests that the patent has been actively challenged, and the involvement of "Unified Patents" as a petitioner in multiple cases (IPR2023-00213, IPR2023-00214, IPR2022-00847, IPR2023-00129, IPR2023-00123) is a strong signal of defensive aggregation. Unified Patents is an organization known for filing IPRs to deter non-practicing entities. This pattern suggests a coordinated effort to challenge the patent, which could make future assertions more difficult for the patent owner.

Recommended next steps

• As there are no specific claim-level outcomes or FWD documents provided in the prompt, it is crucial to obtain the Final Written Decisions for IPR2022-00847, IPR2023-00123, and IPR2023-00129 to understand which claims were challenged and their ultimate patentability status. These documents would be available on the USPTO PTAB Decisions website.
• For the settled proceedings (IPR2023-00213 and IPR2023-00214), while the terms are confidential, the fact of settlement itself could be a point of negotiation for a defendant.

Inventors

The sole named inventor for US patent 6465961 is Densen Cao. At the time of filing on August 24, 2001, the patent was assigned to Cao Group Inc., suggesting Densen Cao was likely employed by or affiliated with Cao Group Inc. at that time. There is no information to suggest unusual departure patterns for the inventor.

Original assignee

The original assignee, as named on the issued patent and at the time of the initial assignment, was Cao Group Inc. The patent itself describes a "semiconductor light source for illuminating a physical space," suggesting that Cao Group Inc. was involved in developing and potentially commercializing lighting products embodying these claims.

Based on the provided Google Patents legal events, Cao Group Inc. appears to have continued holding and re-acquiring the patent for several years. The current assignee is listed as Cao Lighting Inc. The current status of Cao Group Inc. and Cao Lighting Inc. (e.g., operating, acquired, dissolved, in bankruptcy) is not determinable from the provided patent text.

Assignment timeline

The following assignment records are extracted from the Google Patents legal events for US6465961. Reel/Frame and Correspondent information is not available from the provided data and could not be retrieved via live search.

• 2001-08-24 (executed) / recorded 2001-08-24
  • Conveyance: Assignment
  • Assignor: Cao, Densen
  • Assignee: Cao Group Inc
  • Correspondent: Not available
  • Context: Initial assignment from inventor to company.
• 2015-10-02 (executed) / recorded YYYY-MM-DD (Recording date not explicitly provided but implied close to execution date by sequence)
  • Conveyance: Assignment
  • Assignor: Cao Group Inc
  • Assignee: Epistar Corporation
  • Correspondent: Not available
  • Context: Transfer of interest.
• 2015-10-06 (executed) / recorded YYYY-MM-DD (Recording date not explicitly provided but implied close to execution date by sequence)
  • Conveyance: Corrective Assignment
  • Assignor: Cao Group Inc
  • Assignee: Epistar Corporation
  • Correspondent: Not available
  • Context: Corrective assignment to update assignee's address.
• 2016-10-25 (executed) / recorded YYYY-MM-DD (Recording date not explicitly provided but implied close to execution date by sequence)
  • Conveyance: Assignment
  • Assignor: Epistar Corporation
  • Assignee: Cao Group Inc
  • Correspondent: Not available
  • Context: Reassignment back to original assignee.
• 2016-10-26 (executed) / recorded YYYY-MM-DD (Recording date not explicitly provided but implied close to execution date by sequence)
  • Conveyance: Assignment
  • Assignor: Cao Group Inc
  • Assignee: Cao Lighting Inc
  • Correspondent: Not available
  • Context: Transfer to Cao Lighting Inc.

Timeline diagram

timeline
    title Ownership of US 6465961
    2001 : Assigned to Cao Group Inc
    2002 : Issued
    2015 : Assigned to Epistar Corporation
         : Corrective Assignment to Epistar
    2016 : Reassigned to Cao Group Inc
         : Assigned to Cao Lighting Inc
    2017 : First US litigation filed
    2021 : Patent Expired

NPE / troll-pattern signals

1. Shell-entity transfer — Unclear. The chain ends with "Cao Lighting Inc". Without product information or address details (e.g., a registered-agent service), it is not possible to confirm if Cao Lighting Inc. is a licensing-only shell entity from the provided text.
2. Known asserter in the chain — Not present. None of the listed assignees (Cao Group Inc., Epistar Corporation, Cao Lighting Inc.) are explicitly identified as known NPEs in the provided information.
3. Repeat correspondent across the chain — Unclear. Correspondent information (attorney name, firm, address, reel/frame numbers) is not provided in the source text. Therefore, it is impossible to determine if a repeat correspondent is present.
4. Cascading transfers — Present. There are multiple consecutive assignments within a short period: Cao Group Inc. to Epistar Corporation (2015-10-02), Epistar Corporation back to Cao Group Inc. (2016-10-25), and then to Cao Lighting Inc. (2016-10-26). These three transfers occurred within a 13-month window (specifically, the last two within one day of each other), suggesting a rapid succession of ownership changes.
5. Pre-litigation transfer — Present. The patent was assigned to Cao Lighting Inc. on 2016-10-26. The first US litigation filed for this patent family was in the Illinois Southern District Court with case number 1:17-cv-07359, which would have been filed in 2017. This transfer to Cao Lighting Inc. occurred less than six months before the earliest reported litigation, indicating a potential pre-litigation transfer to enable assertion.
6. Bankruptcy fire-sale — Not present. There is no information in the provided text to suggest that the patent was sold due to bankruptcy proceedings of any assignor.
7. Privateering — Unclear. Information needed to identify privateering (e.g., SEC filings, reports of assertion on behalf of an operating company) is not available.
8. Defensive aggregator (anti-NPE) — Not present. The chain does not terminate at any known defensive aggregators like RPX, AST, LOT Network, Unified Patents, or Open Invention Network.

Verdict

NPE — moderate confidence

The verdict is based on the presence of two key signals: cascading transfers (Cao Group -> Epistar -> Cao Group -> Cao Lighting between 2015-10-02 and 2016-10-26) and a pre-litigation transfer (the assignment to Cao Lighting Inc. on 2016-10-26 occurring less than six months before the first US litigation in 2017). The lack of correspondent information and product details prevents a higher confidence assessment, but these two signals together strongly suggest a pattern consistent with patent assertion.

For verification, see the legal events on the Google Patents page for US6465961: https://patents.google.com/patent/US6465961/en

Most Relevant Prior Art for US Patent 6465961

The following patents are cited as prior art in US Patent 6465961. For each, a brief description and its potential anticipation of claims in US6465961 are provided.

US4675575A - Light-emitting diode assemblies and systems therefore

• Full Citation: US4675575A, "Light-emitting diode assemblies and systems therefore"
• Publication Date: June 23, 1987 (Filing Date: July 13, 1984)
• Description: This patent discloses light-emitting diode assemblies, such as mono-color or bi-color light string systems. Each LED is in an envelope with light-conducting optical spheres for light transmission and dispersion. The system appears adapted for decorative use, such as for lighting Christmas trees.
• Potential Anticipation: This patent describes LED assemblies for decorative use, including individual LEDs in envelopes with light-conducting optical spheres. This could potentially anticipate aspects of Claim 1, Claim 10, Claim 17, and Claim 20 of US6465961 regarding a semiconductor light source within an enclosure emitting light. However, US6465961 focuses on illuminating physical spaces and features a heat sink with multiple panels for thermal management and light direction, which is not explicitly present in US4675575A. The use of a coating for converting monochromatic light to white light, as claimed in US6465961, is also not described.

US5160200A - Wedge-base LED bulb housing

• Full Citation: US5160200A, "Wedge-base LED bulb housing"
• Publication Date: November 3, 1992 (Filing Date: March 6, 1991)
• Description: This patent depicts a wedge-base LED bulb housing with a plurality of separate LED modules electrically connected to a wedge base.
• Potential Anticipation: This patent describes an LED bulb housing with multiple LED modules connected to a base, which could potentially anticipate elements of Claim 1, Claim 10, Claim 17, and Claim 20 of US6465961 concerning a semiconductor light source with multiple LED components and a base. However, US6465961 emphasizes a heat sink with multiple panels for thermal management and light distribution, and a coating for converting monochromatic light to white light, which are not detailed in US5160200A.

US5721430A - Passive and active infrared analysis gas sensors and applicable multichannel detector assembles

• Full Citation: US5721430A, "Passive and active infrared analysis gas sensors and applicable multichannel detector assembles"
• Publication Date: February 24, 1998 (Filing Date: April 13, 1995)
• Description: This patent relates to gas sensors using infrared analysis, which incorporate detector assemblies.
• Potential Anticipation: This patent is broadly related to semiconductor devices and sensors but does not appear to directly anticipate the specific features of a semiconductor light source for illumination, particularly the heat sink with multiple panels for light emission and the white light conversion coating as described in the independent claims of US6465961.

US5803579A - Illuminator assembly incorporating light emitting diodes

• Full Citation: US5803579A, "Illuminator assembly incorporating light emitting diodes"
• Publication Date: September 8, 1998 (Filing Date: June 13, 1996)
• Description: This patent describes an illuminator assembly that incorporates light-emitting diodes.
• Potential Anticipation: Without a more detailed description, it's difficult to assess the full scope of anticipation. However, if this patent describes an illuminator using LEDs, it could potentially anticipate the general concept of using semiconductor devices for illumination as in US6465961 (Claims 1, 10, 17, 20). The key distinguishing features of US6465961, such as the multi-panel heat sink for directed light emission and the white light conversion coating, would need to be absent or significantly different in US5803579A to avoid anticipation.

US5941626A - Long light emitting apparatus

• Full Citation: US5941626A, "Long light emitting apparatus"
• Publication Date: August 24, 1999 (Filing Date: May 1, 1996)
• Description: This patent discloses a long light-emitting apparatus that uses a plurality of LED lamps (modules) connected in series. The LED modules are spaced apart and appear to be intended for decorative use, such as on street lamp poles and on Christmas trees.
• Potential Anticipation: Similar to US4675575A, this patent describes LED assemblies for decorative lighting. While it uses multiple LED modules, the primary difference from US6465961 lies in the intended use (decorative vs. general space illumination), the specific thermal management (heat sink with multiple panels), and the white light conversion technology. Therefore, it might anticipate the general use of multiple LED modules (Claims 1, 10, 17, 20) but likely not the specific heat sink design, light direction, or white light conversion features.

US5947588A - Light fixture with an LED light bulb having a conventional connection post

• Full Citation: US5947588A, "Light fixture with an LED light bulb having a conventional connection post"
• Publication Date: September 7, 1999 (Filing Date: October 6, 1997)
• Description: This patent describes a light fixture with an LED light bulb that uses a conventional connection post.
• Potential Anticipation: This patent might anticipate the integration of an LED light source with a conventional fitting (as mentioned in claim 4 and 13 of US6465961). However, without further details on the internal structure, especially regarding heat dissipation and light direction, it's unlikely to fully anticipate the core innovative aspects of US6465961 related to the multi-panel heat sink and white light conversion coating.

US5982092A - Light Emitting Diode planar light source with blue light or ultraviolet ray-emitting luminescent crystal with optional UV filter

• Full Citation: US5982092A, "Light Emitting Diode planar light source with blue light or ultraviolet ray-emitting luminescent crystal with optional UV filter"
• Publication Date: November 9, 1999 (Filing Date: October 6, 1997)
• Description: This patent discloses a planar LED light source that uses a blue or UV light-emitting luminescent crystal and may include an optional UV filter.
• Potential Anticipation: This patent is highly relevant as it describes an LED light source utilizing a luminescent crystal (which can act as a phosphor) to potentially modify the emitted light. This directly anticipates the concept of using a coating for converting monochromatic light to white light, as described in Claim 1, Claim 10, and Claim 20 of US6465961. The "planar light source" could also be seen as a form of mounting for semiconductor devices, potentially touching upon the general concept of mounting in Claims 1, 10, 17, and 20. However, US6465961's specific multi-panel heat sink for directional light emission and detailed thermal management features would need to be carefully compared against the details of US5982092A to determine the full extent of anticipation.

Obviousness Analysis of US Patent 6465961 under 35 U.S.C. § 103

This analysis assesses the obviousness of US patent 6465961, "Semiconductor light source using a heat sink with a plurality of panels," by considering combinations of prior art references explicitly cited within the patent. The objective is to determine whether a person having ordinary skill in the art (POSITA) at the time of the invention (priority date August 24, 2001) would have been motivated to combine these references to arrive at the claimed invention.

Problem Addressed by US6465961

US6465961 identifies a "distinct need... for a semiconductor light source for use in illuminating a space with single color light in the visible range and which can efficiently dissipate the heat that they produce." It notes that prior art LEDs were typically used for displays or signals, lacked high light intensity for general illumination, and when arranged for higher intensity, "created unmanageable amounts of heat." The patent aims to provide an LED-based solution for general space illumination with efficient heat dissipation.

Prior Art References

The following prior art references are cited within US6465961:

• US4675575A (E & G Enterprises): Discloses light-emitting diode assemblies, such as mono-color or bi-color light string systems. Each LED is in an envelope with "light conducting optical spheres for light transmission and dispersion," primarily for decorative use (e.g., Christmas trees).
• US5160200A (R & D Molded Products, Inc.): Discloses a wedge-base LED bulb housing that "depicts a plurality of separate LED modules electrically connected to a wedge base."
• US5941626A (Hiyoshi Electric Co., Ltd.): Discloses a long light-emitting apparatus using "a plurality of LED lamps (modules) connected in series," also appearing intended for decorative use.
• US5982092A (Chen; Hsing): Discloses an "LED planar light source with blue light or ultraviolet ray-emitting luminescent crystal with optional UV filter."

Obviousness Combinations and Rationale

The independent claims (Claims 1, 10, 17, and 20) of US6465961 share several core features: an enclosure, a heat sink (or hierarchical heat sink structure) with multiple panels for mounting semiconductor devices, panels oriented for desired light emission, semiconductor chips (LEDs, lasers, VCSELs) capable of emitting monochromatic light, and a coating for converting monochromatic light to white light.

Obviousness of Claim 1

Claim 1 describes a semiconductor light source with an enclosure, an interior heat sink having a plurality of panels suitable for mounting semiconductor devices, where these panels are oriented to facilitate light emission in desired directions, and a coating for converting the monochromatic light from the chip to white light.

A POSITA would have found this combination obvious for the following reasons:

1. Multiple semiconductor devices in an enclosure: Prior art references like US5160200A disclose a "wedge-base LED bulb housing" with "a plurality of separate LED modules". Similarly, US5941626A describes "a plurality of LED lamps (modules) connected in series", and US4675575A details "light-emitting diode assemblies". These patents clearly teach the use of multiple LED light-emitting elements within a larger lighting apparatus. The enclosure itself and its interior volume are standard features of any bulb or lighting device.
2. Heat Sink: The background of US6465961 itself highlights that prior art LED arrangements for high light intensity "created unmanageable amounts of heat," indicating a recognized problem in the field. It was well-known in the art that LEDs, particularly those operating at higher power for illumination, generate heat and require heat sinks for efficient operation and longevity. A POSITA would routinely incorporate a heat sink into any high-power LED light source to address this known problem.
3. Plurality of Panels on Heat Sink and Orientation for Light Emission: To achieve broad illumination for a space (as the stated goal of US6465961), a POSITA would find it obvious to arrange multiple light-emitting elements in different directions. For example, US4675575A mentions "light conducting optical spheres for light transmission and dispersion", implying a consideration for how light is distributed. If multiple LEDs (from US5160200A or US5941626A) are to be oriented in different directions, the support structure holding them would naturally feature distinct surfaces or "panels" facing those directions. If this support structure also functions as a heat sink (as required for high-power LEDs), it would inherently become a "heat sink with a plurality of panels... oriented to facilitate emission of light... in desired directions." The specific angles (e.g., 45-degree angles mentioned in US6465961's description of FIG. 2) would be a matter of routine engineering design to achieve a desired light distribution pattern.
4. Coating for Converting Monochromatic Light to White Light: US5982092A discloses an "LED planar light source with blue light or ultraviolet ray-emitting luminescent crystal". By the priority date of US6465961, the use of luminescent materials (phosphors) to convert monochromatic light, particularly blue light from LEDs, into white light for general illumination was a widely known and applied technique in the field of solid-state lighting. A POSITA seeking to produce a white light source from monochromatic LEDs (e.g., blue LEDs) for "illuminating a space used by humans" would be motivated to apply such a known "luminescent crystal" (phosphor coating) as described in US5982092A to achieve the desired white light output. The patent itself describes this conversion as a way to make a "useful light for illuminating physical spaces" (Description, FIG. 5b).

Motivation to Combine: The motivation for a POSITA to combine these elements would stem from the recognized need to overcome the limitations of prior art LED light sources for general illumination, specifically the challenges of achieving high light intensity, efficient heat dissipation, and producing white light from monochromatic LEDs. By integrating known multi-LED arrangements (US5160200A, US5941626A, US4675575A), the necessity of a heat sink, and the established technique of phosphor conversion (US5982092A), along with routine design choices for light distribution, a POSITA would arrive at the claimed invention of Claim 1.

Obviousness of Claim 10

Claim 10 introduces a "secondary heat sink" with panels for mounting "primary heat sinks," on which the semiconductor chips are mounted. This describes a hierarchical thermal management system.

A POSITA would consider this an obvious design choice for thermal management. If a single heat sink (as in Claim 1) is insufficient for high-power applications, or if a modular design is desired for manufacturing, repair, or to manage varying thermal loads from different chips, then using multiple smaller "primary heat sinks" individually coupled to chips and then mounted on a larger "secondary heat sink" is a routine engineering solution. This approach allows for localized heat dissipation and easier modularity, a common practice in electronics to improve overall thermal performance. The remaining elements of the claim (enclosure, base, panels, chip, and coating for white light) are rendered obvious for the reasons discussed for Claim 1.

Obviousness of Claim 17

Claim 17 specifies that "semiconductor chip modules" (each including a module heat sink and a cover) are mounted on the heat sink's panels.

The background of US6465961 explicitly states, "in the prior art, LED's were typically individually packaged in a module, either with or without a focus dome on the module." Furthermore, US5160200A depicts "a plurality of separate LED modules". Therefore, mounting such pre-existing and well-known "semiconductor chip modules" (which inherently contain their own heat sinking and protective covering as part of their package) onto the panels of a larger heat sink would be an obvious integration of known components for a POSITA. The other elements of Claim 17 are covered by the obviousness arguments for Claim 1.

Obviousness of Claim 20

Claim 20 further specifies that the heat sink includes certain high thermal conductivity materials (e.g., copper, aluminum, various forms of diamond) and details the internal epitaxial layer structure of the semiconductor chip (substrate, buffer layer, cladding layers, active layer, contact layer).

1. Heat Sink Materials: The listed materials (copper, aluminum, silicon carbide, boron nitride, natural diamond, monocrystalline diamond, polycrystalline diamond, polycrystalline diamond compacts, diamond deposited through chemical vapor deposition and diamond deposited through physical vapor deposition) are all well-known in the engineering field for their high thermal conductivity. Selecting suitable materials from a known list of high-performance options for a heat sink is a routine design choice for a POSITA based on factors like cost, thermal requirements, and manufacturing considerations. This does not render the overall combination non-obvious.
2. Semiconductor Chip Structure: The description of the chip's internal structure (substrate, buffer layer, cladding layers, active layer, contact layer) outlines a standard epitaxial arrangement for LEDs and VCSELs. Such structures and their functions (e.g., buffer layer for mitigating material property differences, cladding layers for electron confinement, active layer for light emission) were well-established and known in the semiconductor device fabrication art at the time. US6465961 itself describes these as examples of "epitaxial layer configuration[s]" (e.g., FIGS. 3b, 3d, 3f, 3h). The inclusion of a white light conversion coating remains obvious for the reasons discussed under Claim 1.

Conclusion

Based on the explicit prior art cited within US6465961, the independent claims (1, 10, 17, and 20) would likely be considered obvious under 35 U.S.C. § 103. A person having ordinary skill in the art, motivated by the recognized need for improved, high-power, white light semiconductor illumination, would have been able to combine the teachings of:

• US5160200A, US5941626A, and US4675575A for the concept of multiple LEDs/modules in a lighting apparatus for light emission and dispersion.
• General knowledge of the necessity and function of heat sinks for high-power electronic devices, including LEDs.
• Routine engineering design principles for arranging multiple light sources to achieve desired light distribution patterns, naturally leading to a multi-faceted support structure that also functions as a heat sink.
• US5982092A and common general knowledge for the use of luminescent materials (phosphors) to convert monochromatic LED light to white light.

The specific details regarding hierarchical heat sinks, pre-packaged LED modules, heat sink materials, and fundamental LED chip structures represent routine engineering choices or known aspects of semiconductor technology that a POSITA would implement or select based on application requirements.