Federal Circuit Rejects District Court’s Overly Narrow Claim Construction in LED Patent Infringement Case

On October 16, the U.S. Court of Appeals for the Federal Circuit issued a ruling in CAO Lighting, Inc. v. Feit Electric Co., Ltd. vacating a summary judgment entered by the Central District of California that found Feit Electric did not infringe semiconductor light source patent claims asserted by CAO Lighting. In so ruling, the Federal Circuit found that the district court erred in construing the claim term “first reflective layer,” and in requiring that the claimed first reflective layer be composed of a different material than the substrate upon which the layer is deposited.

CAFC Not Compelled to Limit Broad Claim Term by Narrow Limitation in Separate Claim

In June 2020, CAO Lighting filed a patent infringement suit in Central California district court asserting claims from U.S. Patent No. 6465961, Semiconductor Light Source Using a Heat Sink with a Plurality of Panels. The ‘961 patent claims a semiconductor light source for illuminating a space while efficiently dissipating heat and relates to Light Emitting Diode (LED) technology. The district court conducted a Markman hearing in September 2021 in which the court construed the claim term “reflective layers” as “distinct layers of material that reflect light emitted by said active layer.”

Following Markman, Feit Electric moved for summary judgment of noninfringement, arguing that CAO Lighting identified a boundary between layers as the first reflective layer and not a distinct layer of material. Although CAO Lighting identified a patterned portion of the claimed sapphire substrate as the reflective layer, Feit Electric countered that the substrate and first reflective layer were claimed in the ‘961 patent as separate limitations. After ordering supplemental briefing on the construction of claim terms related to epitaxial layers, or crystalline layers grown on top of another crystal that determines the formed layer’s orientation, the district court granted Feit Electric’s summary judgment ruling because the first reflective layer and the substrate in the accused products were not composed of different materials.

On appeal, the Federal Circuit reviewed the Central California district court’s claim construction de novo as it was based entirely on intrinsic evidence from the patent itself. Reading the claims of the ‘961 patent, the Federal Circuit noted that the claim language did not require the claimed reflective layers to be epitaxial. For example, canceled claim 7 of the ‘961 patent, the independent claim from which CAO Lighting’s asserted claim depends, specifically recites an epitaxial layer whereas claim 8 of the ‘961 patent simply refers to reflective layers. Citing to its 2014 ruling in Ancora Technologies v. Apple, the Federal Circuit declined to limit the broader term from claim 8 by the narrower interpretation contained within claim 7.

Case Remanded So Parties Can Address Infringement Under Proper Claim Construction

Feit Electric contended that the ‘961 patent only mentions reflective layers in the context of a vertical-cavity surface-emitting laser (VCSEL). Although the ‘961 patent’s specification describes the reflective layers of a VCSEL as epitaxial, the Federal Circuit cited several cases, including Williamson v. Citrix Online (2015), for the premise that claimed inventions are not limited to preferred embodiments included in the specification unless the inventor makes it clear that the specification is of equal scope to the claims. Because no such clear language existed in the specification, the Federal Circuit concluded that the claimed first reflective layer need not be epitaxial.

The Federal Circuit’s correction of the district court’s claim construction also led the appellate court to reverse the lower court’s finding that the first reflective layer and substrate must be composed of different materials. The district court had so concluded because claim 7 required a buffer layer mitigating differences in material properties between the substrate and epitaxial layers. However, because the Federal Circuit concluded that the claimed reflective layers need not be epitaxial, the “other epitaxial layers” of claim 7 did not encompass the reflective layers of claim 8 such that the first reflective layer was required to be composed of a different material than the sapphire substrate.

Finally, the Federal Circuit nixed Feit Electric’s arguments that the district court’s summary judgment ruling could be affirmed on other grounds. Feit Electric’s first argument, that the patterned substrate must be epitaxial to meet the claimed first reflective layer, was undone by the appellate court’s reversal on claim construction. As to Feit Electric’s argument that the first reflective layer and the substrate cannot be the same component, the Federal Circuit noted that both of those limitations were contained within different claims. However, because the district court’s dismissal of this argument also rested upon its erroneous claim construction, the Federal Circuit remanded this issue to the district court to give both parties an opportunity to properly address it.