CAFC says District Court Erred in Claim Construction in Blackbird Patent Case

On Monday, July 16th, the Court of Appeals for the Federal Circuit issued a precedential decision in Blackbird Tech v. ELB Electronics, which vacated an earlier judgment of non-infringement of a patent asserted by Blackbird in the District of Delaware. The Federal Circuit panel of Chief Judge Sharon Prost and Circuit Judge Kimberly Moore determined that the district court had erred at construing the claim term “attachment surface” in finding non-infringement of the asserted claims. Circuit Judge Jimmie Reyna dissented in this case.

The patent-at-issue is U.S. Patent No. 7086747, titled Low-Voltage Apparatus for Satisfying After-Hours Lighting Requirements, Emergency Lighting Requirements, and Low Light Requirements. Issued in August 2006, it covers an energy-efficient lighting apparatus having a ballast cover, a plurality of ballast cover holes, a circuit board having a plurality of light-emitting diodes (LEDs) which protrude through the ballast cover holes, wherein the lighting apparatus is connected to a wall switch and the illumination of the LEDs is based upon the position of the wall switch. The resulting invention provides a lighting apparatus which meet after-hours or emergency lighting requirements more efficiently and conveniently for commercial building environments.

Blackbird first asserted the ‘747 patent against ELB Electronics in a patent infringement complaint filed in January 2015. An amended complaint filed by Blackbird in July 2016 alleged that ELB infringed upon the ‘747 patent through the sale of LED tube light components of an energy-efficient lighting apparatus that retrofits an existing light fixture with a ballast cover and is coupled to a wall switch. Judge Richard Andrews signed a stipulated order of non-infringement in February 2017 following a claim construction opinion filed the previous December where the court construed the term “attachment surface” to mean “layer of the housing that is secured to the ballast cover.” Although Blackbird stipulated to the non-infringement judgment, it appealed the claim construction findings from Delaware district court.

In finding that the district court erred in construing the claim term, the Federal Circuit majority found that the plain language of the “attachment surface” claim term did not require it to be secured to the ballast cover. The claim introducing the “attachment surface” term also recites a fastening mechanism for securing the attachment surface to the illumination surface. In construing “attachment surface” to require such securing to the ballast cover, the district court read in an extra fastening mechanism into the claim, the Federal Circuit majority held. Further, the prosecution history of the ‘747 patent supported the fact that the fastening mechanism wasn’t technologically significant and therefore shouldn’t have been read in as a claim limitation. The Federal Circuit cited a claim amendment made during the patent’s prosecution in which the applicant eliminated a requirement that a fastening mechanism secures the attachment surface to the ballast cover. The panel majority vacated the Delaware judgment and adopted Blackbird’s construction of “attachment surface” to mean “layer of the housing to which the illumination surface is secured.”

Judge Reyna’s dissent held that the district court properly construed the “attachment surface” claim. The plain language of the claim, which expressly describes a lighting apparatus for retrofit with an existing light fixture having a ballast cover, “implicitly requires that the attachment surface be secured to the ballast cover to achieve the retrofit function” when read in the context of the specification. The word “retrofit” written into the claim’s preamble implied securing the lighting apparatus to something, making it reasonable to conclude that the “attachment surface” was involved in achieving the retrofit function.

In not recognizing that the attachment surface is described throughout the specification as securing the lighting apparatus to the ballast cover, the majority gave no meaning to “attached” beyond what was already in the claim language, Judge Reyna argued. He also noted that the majority’s construction opened the door for the ‘747 patent to be rendered invalid for failure to satisfy the written description requirement. The majority’s construction doesn’t disclose how the apparatus is installed, then the claim language doesn’t disclose how the retrofit function is to be achieved.


Warning & Disclaimer: The pages, articles and comments on do not constitute legal advice, nor do they create any attorney-client relationship. The articles published express the personal opinion and views of the author as of the time of publication and should not be attributed to the author’s employer, clients or the sponsors of

Join the Discussion

No comments yet.