The Doctrine of Claim Differentiation: Who Got It Right in Retractable Technologies?

Chief Judge Randall Rader of the Federal Circuit

One of the canons in the perplexing world of patent claim construction is the doctrine of claim differentiation.  As stated in the seminal 2005 claim construction case of Phillips v. AWH Corp., this doctrine holds that “the presence of a dependent claim that adds a particular limitation gives rise to a presumption that the limitation in question is not present in the independent claim.”  But the recent case of Retractable Technologies, Inc. v. Becton, Dickinson & Co. saw a split panel of the Federal Circuit take very divergent views on whether the “presumption” created by this doctrine was rebutted by other facts.  In my opinion, dissenting Chief Judge Rader’s  view is correct.  Rader explained that the “strong presumption” created by this doctrine was not rebutted by the facts in this case.  Conversely, the view of Judge Lourie (writing for the panel majority that included Judge Plager) was that this “implication [was] not a strong one” and won’t hold up under careful scrutiny.

In Retractable Technologies, the claimed invention related to retractable syringes, i.e., medical syringes that feature a needle that retracts into the syringe body after the syringe is used.  Independent Claim 1 of U.S. Pat. No. 7,351,224 (the “’224 patent”) recited a “syringe comprising a hollow body,” while independent Claim 43 of the ’224 patent recited a syringe assembly which comprised a “hollow syringe body.”  Dependent Claim 14 of the ’224 patent recited “[t]he syringe of claim 1 comprising a one-piece barrel,” while dependent Claim 57 recited “[t]he syringe assembly of claim 43 wherein the body comprises a one-piece barrel.”  In other words, both dependent Claim 14, as well as dependent Claim 57, were limited to a “one-piece” structure for the “hollow [syringe] body.”  And under the doctrine of claim differentiation, that would raise the “strong presumption” that the “hollow [syringe] body” of independent Claims 1 and 43 need not be a “one-piece” structure, but could also be a “multi-piece” structure.

Whether the term “body” encompassed “multi-piece” structures became the crux of the claim construction issues in Retractable Technologies.  The District Court for Eastern Texas, apparently applying the doctrine of claim differentiation, construed independent Claims 1 and 43 to cover a “body” which might be a “multi-piece” structure.  Accordingly, the District Court denied post-trial motions by the alleged infringer (Becton Dickinson or “BD”) to overturn the jury verdict that BD infringed these Claims of the ‘224 patent.

Judge Lourie (writing for the panel majority) reversed the District Court, ruling that the term “body” was limited to a “one-piece” structure in light of the ‘224 patent specification (as well as the specifications of two other patents that were asserted to be infringed).  In fact, Judge Lourie’s opinion barely acknowledges that the doctrine of claim differentiation was in play (only stating that BD argued that “claim differentiation does not apply in light of the written description’s limiting statement [in the ‘224 patent specification]”).  While noting that the some of the dependent Claims of the ‘224 patent limited the “body” to a “one-piece body,” Judge Lourie also observed that “none of the claims expressly recite a body that contains multiple pieces.”  Accordingly, while the claims could “be read to imply that the body’ [wasn’t] limited to a one-piece structure, that implication [wasn’t] a strong one.”

Instead, Judge Lourie reached for another canon of claim construction from the Phillips case, namely “the claim language must always be read in view of the written description” in the patent specification.  In this regard, Judge Lourie noted the following facts from the ‘224 patent specification (as well as the other patent specifications) that suggested the term “body” was limited to one-piece structures:  (1) describing the prior art as “fail[ing] to recognize” that a retractable syringe could be molded as a one piece outer body; (2) the Summary of the Invention section stated that the syringe “features a one piece hollow body”; and (3) “each syringe embodiment” was described as “contain[ing] a one-piece.” In contrast, the “[patent] specifications [including that of the ‘224 patent] do not disclose a body that consists of multiple pieces or indicate that the body is anything other than a one-piece body.”  Accordingly, “while the claims leave open the possibility that the recited ‘body’ may encompass a syringe body composed of more than one piece, the specifications tell us otherwise.”

In Judge Plager’s concurring opinion, the doctrine of claim differentiation is conspicuous by the absence of any mention of this claim construction canon.  Instead, Judge Plager focused almost exclusively on the alleged “curse of indefinite and ambiguous claims, divorced from the written description, that we regularly are asked to construe, and the need for more stringent rules to control the curse.”  In other words, Judge Plager viewed the claim construction issue in Retractable Technologies as being one of “written description” under 35 U.S.C. § 112, first paragraph, and possibly (though ambiguously stated) of “indefiniteness” under 35 U.S.C. § 112, second paragraph.

But what about the “presumption” under the doctrine of claim differentiation against importing limitations into the independent claim(s) which are recited in the dependent claim(s) (as Chief Judge Rader figuratively “screamed” in his blistering dissent)? Instead, Chief Judge Rader referred to another claim construction canon from the Phillips case:  the claims themselves, not the written description portion of the specification, define the claimed invention.  In referring to yet another claim construction canon from Phillips (claim language is to be given its ordinary and customary meaning), Chief Judge Rader observed that “neither party contends that ‘body’ has a special, technical meaning in th[is] field of art.”  That meant that the claim construction required “little more than the application of the widely accepted meaning of commonly understood words,” i.e., did not mean that the term “body” was limited to one-piece structures.

Instead, and firmly relying upon the doctrine of claim differentiation, Chief Judge Rader pointed to the claim language as evidencing that the term “body” was not limited to one-piece structures.  In fact, Chief Judge Rader observed that the “presumption” created by this doctrine is “especially strong when the limitation in dispute is the only meaningful difference between an independent and dependent claim, and one party is urging that the limitation in the dependent claim should be read into the independent claim” (citing the 2003 Federal Circuit decision in SunRace Roots Enterprise Co. v. SRAM Corp.)

While Chief Judge Rader agreed that the claims “must be read in light of the specification,” he further stated that nothing in the patent specifications (including that of the ‘224 patent) rebutted the “strong presumption” created by the claim language that “body” does not contain a one-piece structural limitation.  In sum, construing the claim term “body” in these patents (including the ‘224 patent) as being limited to a one-piece structure was viewed by him as “contrary to the ordinary and customary meaning of the word ‘body,’ violat[ing] the doctrine of claim differentiation, and lack[ing] support in the patents at issue.”

Admittedly, the patent applicant in Retractable Technologies might have avoided this claim construction conundrum by specifically exemplifying multi-piece “body” embodiments in the patent specifications, and especially by avoiding such limiting references in the Summary of the Invention section (which unfortunately has created another faulty “presumption” in the minds of some judges that the claimed invention is somehow limited by what is described in this section).  The patent applicant in Retractable Technologies may also have dangerously flirted with a potential lack of “enablement” issue under 35 U.S.C. § 112, first paragraph, in not specifically exemplifying multi-piece “body” embodiments.  But Chief Judge Rader is on solid footing in arguing that the “presumption” created by the doctrine of claim differentiation mandates strongly against reading limitations of the dependent claims into the independent claims, and wasn’t effectively rebutted with respect to the term “body.” For the panel majority (through Judge Lourie) to say that this “implication is not a strong one” in Retractable Technologies defies the facts, logic, and most significantly, binding Federal Circuit precedent.

© 2011 Eric W. Guttag.