How Big a Role does the Specification Play in Construction of Patent Claims?

Bernadette McGann and Kumiko Ide | July 14, 2011


 先週金曜日に下された、CAFCのRetractable Technologies v. Becton, Dickinson判決は、明細書中で曖昧な記載がされている場合、裁判所は、クレームを狭く解釈する恐れがあるため、特許権者にとって危険であることを示す。裁判所がクレームを狭く解釈する可能性をできるだけ低くするための明細書記載についてのレッスンは以下の3つである。

(1)   明細書の「発明の背景(Background of the Invention)」のセクションにおいて、先行技術は発明の特定の特徴を開示していないことについてコメントすることを控える。裁判所は、そのコメントについて、クレーム発明は、その特徴を必要としていると解釈し、クレームをそれに応じて限定する可能性がある。

(2)   明細書の「課題を解決するための手段(Summary of the Invention)」のセクションにおいて、クレーム中に記載されていない発明の特徴を説明することを控える。上記と同じように、裁判所は、そのコメントについて、クレーム発明は、その特徴を必要としていると解釈し、クレームをそれに応じて限定する可能性がある。

(3)   主クレームの用語ができるだけ広く解釈されるように、クレーム用語を狭く定義するいくつかの従属クレームを記載する

The CAFC’s decision last Friday in Retractable Technlogies v. Becton, Dickinson demonstrates the risk of a loosely-worded specification for the patentee – specifically, the risk that a court might use to construe claims narrowly.  Here are three lessons for writing the specification and claims in a way that reduces the risk that a court will construe the claims narrowly:

(4)   In the “Background of the Invention” section of the specification, do not comment that the prior art fails to disclose a certain feature of the invention – a court could construe that comment to mean that the claimed invention requires that feature and limit the claims accordingly.

(5)   In the “Summary of the Invention” section of the specification, do not describe the invention as including a feature that is not recited in the claims – again, a court could construe that comment to mean that the claimed invention requires that feature and limit the claims accordingly.

(6)   Increase the likelihood that a term in the main claim will be construed broadly by including several dependent claims that define the claim term narrowly.


The Retractable Technologies, Inc. (hereinafter RTI) patents are directed towards retractable syringes, which are medical syringes, wherein the needle retracts into the syringe body after the syringe is used.  This reduces the risk of accidently resticking.





 24 – Compressed spring

32 – Retainer

42 – Cutting tip

In retraction syringes, the retraction mechanism is a combination of the needle holder and the spring.  The needle holder contains a circular head, and the clamping or frictional force on the head holds the needle holder in position.  When the plunger is depressed, this causes the retraction mechanism to activate and release the needle.  (Figure 2)

RTI sued Becton, Dickinson & Co. (hereinafter BD) for infringement alleging that two of BD syringes infringed several claims in several patents.  A jury trial held that the BD syringes infringed. 

BD appealed the final judgment of the district court.  BD challenges the construction of the claimed terms “retainer member” and “body” by the district court.  BD also challenges the district court excluding from the claim scope “cutting”, as a mechanism for retracting a needle.

Representative Claim 43 of U.S. Patent No. 7,351,224

43.   A syringe assembly having a retractable needle that is rendered unusable after a single injection of fluid into a patient, the assembly comprising:

a hollow syringe body comprising a barrel and having a front end portion and a back end portion, the back end portion further comprising at least one radially extending member providing finger grips for the syringe body;

a retraction mechanism disposed in the front end portion, the retraction mechanism further comprising a needle holder having a head portion, an elongated needle holding portion, and a longitudinally extending fluid passageway through the head portion and the elongated needle holding portion, the head portion further comprising an inner head, a continuous retainer member surrounding the inner head, and a bridging portion disposed between the continuous retainer member and the inner head, wherein said bridging portion couples the continuous retainer member and the inner head to form a fluid seal between the fluid passageway and the barrel prior to retraction, and a compressed retraction spring surrounding at least part of the elongated needle holding portion and biasing the inner head toward the back end portion prior to retraction;

a retractable needle extending into the front end portion of the body through an opening in the front end portion of the body, the retractable needle being held in fixed relation to the elongated needle holding portion of the needle holder and in fluid communication with the longitudinally extending fluid passageway through the head portion and the needle holding portion;

a plunger reciprocally disposed inside the barrel and forming a variable chamber between the plunger and the needle holder prior to and during injection, the plunger being receivable into the barrel through the back end portion of the body and comprising an outer wall, a retraction cavity disposed inwardly of the outer wall, a plunger seal element providing sliding, sealed engagement between the plunger and the barrel and preventing fluid leakage between the plunger and the barrel, the plunger seal element being restrained from sliding longitudinally along the outer wall of the plunger, and a back end with an end cap having an outer periphery; and

a barrier disposed in the front end portion of the body that limits forward motion of the needle holding portion and the retractable needle relative to the body as the plunger is depressed inside the barrel during injection and retraction;

wherein the continuous retainer member is releasable from the inner head of the needle holder when the plunger is further depressed inside the barrel following injection.

Representative Dependent Claim 57 of U.S. Patent No. 7,351,224

The syringe assembly of claim 43 wherein the body comprises a one-piece barrel.

District Court Proceedings

The district court construed the term “retainer member” as “a non-retractable part of the retraction mechanism that uses some clamping or frictional force to keep the needle in the projecting position until that clamping or frictional force is released.  The district court also construed that the claimed “retainer member” and the “needle holder” need not be two separate parts.

The district court held that the term “body” as “a hollow outer structure that houses the syringe’s components” and concluded that the term “body” was not limited to a one-piece structure. 

The district court concluded that the patents did not disclaim the use of “cutting” as a mechanism for retracting a needle.  The district court concluded that “whether the accused devices’ use of ‘cutting’ fell within the scope of the claims was a question of fact, not a matter of claim construction.”

The Law

  • To ascertain the scope and meaning of the asserted claims, we look to the words of the claims themselves, the specification, the prosecution history, and any relevant extrinsic evidence. Phillips v. AWH Corp., 415 F.3d 1303, 1315-1317 (Fed. Cir. 2005) (en banc).
  • Claim language must always be read in view of the written description.  Id. at 1315.
  • Any presumption created by the doctrine of claim differentiation will be overcome by a contrary construction dictated by the written description or prosecution history.  Seachange Int’l, Inc. v. C-COR, Inc., 413 F.3d 1361, 1369 (Fed. Cir. 2005). 
  • There is a fine line between construing the claims in light of the specification and improperly importing a limitation from the specification into the claims.  Phillips, 415 F.3d at 1323.
  • In reviewing the intrinsic record to construe the claims, we strive to capture the scope of the actual invention, rather than strictly limit the scope of the claims to disclosed embodiments or allow the claim language to become divorced from what the specification conveys is the invention. Id. at 1323-24.


Retainer Member

BD argued that retainer member and needle holder must be separate pieces because the claims recite them as separate claim limitations, the specification discloses the retainer member as a separate part from the holder member and that connecting the two pieces via a tack weld, i.e., bridge embodiment, is different than forming the elements as a single piece. 

The CAFC disagreed with BD and affirmed the district court construction.  The CAFC cited as support for the district court construction several passages of the specification and cited RTI claim language.  The CAFC also held that the prosecution history does not contradict the construction of the district court. “The asserted claims lack language that limits the needle holder or the retainer member to elements that are ‘made of’ one piece.”  RTI v. BD, at 14-15.

The CAFC disagreed with BD’s arguments with regards to the bridge embodiment.  The specification disclosed that the retainer member and the inner head of the needle holder can be connected by a weld (i.e., bridge), and retraction occurs when the weld is ruptured or separated.  The CAFC held that by welding the two elements, there is one piece and that the action of rupture, fractured or otherwise separated resulted in the elements being two pieces. 





66a – Retainer member

73 – Bridge/welding connection

72a – Inner head


BD argues that the specification defines the invention as being “one-piece body” and that the specification criticizes the syringes of the prior art for containing a two-piece body.  BD also argues that claim differentiation does not apply in light of the written descriptions’ limiting statements. 

The CAFC agreed with BD and reversed the district court.  The court noted that the independent claim recites body, that dependent claims limit the scope of the body to a one-piece body, and there were no claims expressly reciting a body that contains multiple pieces.  “Thus, while the claims can be read to imply that a ‘body’ is not limited to a one-piece structure, that implication is not a strong one.”  RTI v. BD, at 15-16.

First, the CAFC noted that the background section of the specification stated that the prior art failed to recognize a retractable syringe that can be molded as an one piece outer body.  Next, the Summary of the invention section of the specification stated that “the invention is a retractable tamperproof syringe”, and that this syringe “features a one piece hollow body.”  See U.S. Patent No. 7,351,224, Col. 3, lines 16-18.  The CAFC also noted that each of the embodiments disclosed contained a one-piece body.  Thus, there was no disclosure directed towards a body consisting of multiple pieces or indication that the body is anything other than a one-piece body.  Lastly, the CAFC held that while the claims leave open the possibility that the recited body may encompass a syringe body composed of more than one piece, the intrinsic evidence define the term as being a
one-piece body.

  • Specification expressly recited that “the invention” has a body construed as a single structure. 
  • The one-piece body feature expressly distinguishes “the invention” from the prior art. 
  • All the disclosed embodiments possess a one-piece body.

“Thus, a construction of ‘body’ that limits the term to a one-piece body is required to tether the claims to what the specifications indicate the inventor actually invented.”  RTI v. BD, at 17.


  • To disavow claim scope, the specification must contain expressions of manifest exclusion or restriction, representing a clear disavowal of claim scope.  Epistar Corp. v. Int’l Trade Comm’n, 566 F.3d 1321, 1335 (Fed. Cir. 2009)
  • In general, statements about the difficulties and failures in the prior art, without more, do not act to disclaim claim scope.  Spine Solutions, Inc. v. Medtronic Sofamor Danek USA, Inc., 620 F.3d 1305, 1315 (Fed. Cir. 2010)


BD argued that the specification expressly criticized and distinguished prior art devices that operate by methods other than friction.  BD argued that these statements disclaim devices that operate by “cutting” and thus, the claims should be construed as excluding a “cutting” mechanism.

The CAFC held that the claims language, the specification and the prosecution history did not contain a clear expression disavowing the “cutting” mechanism, and thus affirmed the district court.  The CAFC held that the bridge embodiment wherein the bridge is ruptured, fractured or otherwise separated, indicated that at least some form of “cutting” falls within the scope of the invention.  The CAFC noted that the Background section of the specification did not expressly disavow a cutting mechanism but rather discussed particular problems with the prior art, such as the need for flexing or breaking of internal parts by the plunger or the need for a diaphragm on the plunger to penetrate the needle holding member and spring.

Merely discussing the problems of the prior art, without a clear manifestation to exclude or restrict the claims, will not limit claim scope.

Concurring Opinion

The concurring opinion by Judge Plager reiterated and focused on disclosure of the specification.  According, he held that the focus of claim construction should be to construe the claims in light of what the actual invention is, as disclosed by the intrinsic evidence.  “[T]he claims cannot go beyond the actual invention that entitles the inventor to a patent.” RTI v. BD, concurring opinion at 2.  The specification is the heart of the patent.  In colloquial terms, you should get what you disclose.  Arlington Industries, Inc. v. Bridgeport Fittings, Inc., 632 F.3d 1246, 1252 (Fed. Cir. 2011).


The dissent, written by Chief Judge Rader asserted that the majority misconstrued the term body.  The dissent held that Phillips holds that the claims themselves, not the written description proportion of the specification, define the invention.  The dissent agrees that claims do not stand alone and must be read in light of the specification, but holds that in the present case, the specification does not rebut the strong presumption created by the claim language that the body does not contain a one-piece structural limitation. 

Suggested Alternative Course of Action:

When drafting the specification, the Drafter should be careful with regards to making definitive statements that can be construed as defining “the invention.”  In the case at hand, the specification recited that “The syringe structure features a one piece hollow outer body having a longitudinally extending wall which is stepped.”  See U.S. Patent No. 5,632,733, Col. 2, lines 45-47, the first paragraph after the header “Summary of the Invention”.  Furthermore, the specification did not present any alternative embodiments of the body feature. 

Therefore, presenting only one embodiment coupled with a definitive statement that the invention is X, may limit claim scope and can affect claim construction under the doctrine of claim differentiation.

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