PTAB Decision: Blackbird Tech LLC v. ELB Electronics, Inc., 2018 WL 3421094 (Fed. Cir. 2018).
Background: Blackbird is the owner of U.S. Patent 7,086,747, which is directed to energy efficient lighting apparatuses. Blackbird sued for infringement of claim 12 of the '747 patent in the District of Delaware. Claim 12 reads:
12. An energy-efficient lighting apparatus for retrofit with an existing light fixture having a ballast cover, comprising:
a housing having an attachment surface and an illumination surface; ...
and
a fastening mechanism for securing the attachment surface of the lighting apparatus to the illumination surface ....
(emphasis added)
Issue: The parties disputed the meaning of the claim term "attachment surface," specifically whether the attachment surface must be secured to the ballast cover of the existing light fixture. Blackbird proposed the construction "layer of the housing to which the illumination surface is secured," meaning the attachment surface is only secured to the housing's illumination surface. Defendants proposed "layer of the housing that is secured to the ballast cover and to which the illumination surface is secured," meaning the attachment surface must be secured to both the illumination surface and the ballast cover of the existing fixture.
Outcome: Judge Richard G. Andrews of the district court determined that the proper construction of "attachment surface" was "layer of the housing that is secured to the ballast cover." In view of His Honor's claim construction, Blackbird stipulated to infringement, and the district court entered judgement in favor of the defendants. Blackbird appealed the judgement of infringement based on the district court's construction of "attachment surface."
Circuit Judge Moore authored the Federal Circuit majority opinion in Blackbird, joined by Chief Judge Prost, with Circuit Judge Reyna dissenting. The majority held that the district court erred in its claim construction of "attachment surface" and adopted Blackbird's original construction of "layer of the housing to which the illumination surface is secured." The majority vacated and remanded the case.
Specifically, the majority held that the claim limitation "attachment surface" did not require securing the attachment surface to the ballast cover because the plain language of the claim does not require it and because the specification and prosecution history provide no suggestion that this form of fastening merits requires that the form be read into claim 12.
The only fastening mechanism claim 12 recites secures the attachment surface to the illumination surface—it does not refer to any other fastening mechanism. A second fastening mechanism should not be read into the limitations of the claims, even though it is discussed in the specification. The discussion of fastening the attachment surface to the ballast cover in the specification should not be imported into the claim. The specification never refers to the second fastening mechanism as the "present invention," an "essential element" of the invention, or uses any other language that would lead a person of skill in the art to believe this fastening mechanism is critical to the invention. The Court said that even though the fastener for securing the attachment surface to the ballast cover is described in the Summary of the Invention, that is not determinative. The Court said that in the past, when limitations were read into the claim, it was not merely because of the presence of those elements in the Summary of the Invention, but something more—specific language making clear those limitations were important.
Because there is no evidence in the specification that the fastener connecting the attachment surface to the ballast cover is "important, essential, or critical" to the invention, the majority refused to read it into claim 12 as a claim limitation.
The final ground for the court's reasoning ("and possibly the most important reason") was the prosecution history related to claim 12. The limitation of a fastener for connecting the attachment surface to the ballast cover was expressly eliminated from claim 12 during prosecution. Because the fastener for securing the attachment surface to the ballast cover was "undisputedly and unequivocally deleted from the claim," the majority held it was not a limitation in the current claim.
The Court dismissed the Defendant's argument that the preamble requires reading in fastening the attachment surface to the ballast cover for the claim to achieve its "retrofit" function. The majority said that as an apparatus claim, claim 12 is structurally complete. An apparatus claim does not need to include all the elements necessary for installation of the claimed structure. The claim does not (and is not required to) describe how the lighting apparatus is installed.
Circuit Judge Reyna would have affirmed the district court's construction of "attachment surface" to mean "layer of the housing that is secured to the ballast cover."
Judge Reyna stated that by construing the attachment surface to mean the layer of the housing to which the illumination surface is secured, the majority failed to give meaning to the terms "retrofit" and "having a ballast cover." Therefore, the majority gave the patent owner protection that is broader than that supported by the specification.
Judge Reyna also stated the disclosures in the claims and specification, when taken collectively and combined with the lack of intrinsic evidence showing the attachment surface secured to anything but the ballast cover, teach a skilled artisan that the attachment surface is secured to the ballast cover of the existing light fixture.
Judge Reyna also disagreed with the majority's choice to ignore function in construing "attachment surface." In addition, Judge Reyna pointed out that because the majority's opinion did not describe how the lighting apparatus is to be secured to an existing light fixture, it effectively reads out the retrofit function of both claims 12 and 29 (the method of retrofitting). If "attachment surface" is not construed to include securement to the ballast cover, then method claim 29 fails to disclose how to achieve the retrofit function. As a result, the majority's construction may invite written description and enablement challenges.
Finally, Judge Reyna found the majority's reliance on the prosecution history misplaced. The prosecution history did not explain the purpose or effect of the amendment on claim scope. Judge Reyna stated the amendment is ambiguous as to the scope of the disputed claim limitation and should not affect the proper construction of "attachment surface." "An ambiguous amendment, such as here, should not negate the evidence in the specification and the conclusion implicit in the claim language that the attachment surface is secured to the ballast cover."
Prosecution Takeaway: If a limitation is described in the Summary of the Invention section of the specification, it is not, per Blackbird, automatically read into the claims. However, such a limitation is not necessarily read out of the claims either. There is an inherent tension in claim construction between what is in the specification (beyond what is claimed) and the claims themselves.
It has long been recognized that "a court may not read into a claim a limitation from a preferred embodiment, if that limitation is not present in the claim itself." Bayer AG v. Biovail Corp., 279 F.3d 1340, 1348 (Fed. Cir. 2002). On the other hand, "when the preferred embodiment is described in the specification as the invention itself, the claims are not necessarily entitled to a scope broader than that embodiment." SciMed Life Sys. v. Advanced Cardiovascular Sys., 242 F.3d 1337 (Fed. Cir. 2001) (quoting Modine Mfg. Co. v. United States Int'l Trade Comm'n, 75 F.3d 1545, 1551 (Fed. Cir. 1996)).
The tension between these two principles was apparent in this case. The two-judge majority held the limitation should not be read in, but two judges (one district court judge and one Federal Circuit dissenter) read the limitation into the claims.
For patent drafters and prosecutors, the lesson of Blackbird is to carefully consider using phrases such as "the present invention is" or "an essential element of the invention is." Any time the patent describes "the present invention" or an "essential element" of the invention, the inventor risks disclaiming any subject matter that does not fall within the description.
However, if the description is just "disclosing" an apparatus, without claiming it is the current invention, it appears that at least one panel of the Federal Circuit will not limit the patent claims to that description. This is true even if the description is located in the Summary of the Invention—per Blackbird, precise location within the patent is not determinative. Although, it is worth considering that leaving unclaimed terms out of the Summary of the Invention could further help the patent owner avoid incorporation of such terms into the claims.
Pre-litigators and litigators, as well as third party analysts, should seek to find language in the specification such as "the present invention is" or emphasis on "essential" or "critical" elements in the patents they analyze. If a narrow claim construction is desired, that language can be accentuated in claim construction arguments. A patent owner may wish to have a narrower construction to avoid a holding of unpatentability/invalidity before the PTAB or a U.S. district court. However, if a broad claim construction is desired, that language will have to be addressed and minimized.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
