The invention operates by having the user apply pressure to the actuating means either manually, e.g., squeezing a pump handle, or through an electrical means, e.g., an electric motor. This results in the diaphragm being upwardly distorted. According to the patent, the upward distortion of the diaphragm creates negative pressure in the nipple region sufficient to simulate lactation. Id., col. 1, ll. 54-57. The negative pressure is confined to the nipple region and the upper portion of the pump body by a valve that closes when negative pressure is created, but opens as the pressure is being relieved. Opening of the valve allows the milk, which was trapped in the pump body while in the negative-pressure state, to flow into a receiving container. The nursing mother’s milk is accumulated by repeatedly applying and releasing pressure to the actuating means, thereby repeatedly creating and relieving negative pressure in the nipple region and the body of the pump.

The court construed the claim limitation “diaphragm disposed in the body” as a diaphragm that is “disposed of or mounted entirely within the body of the pump.” Id., slip op. at 19. To arrive at its claim construction, the court referenced the patent specification’s description of the first, in terms of its appearance in the patent, of two disclosed embodiments and explained that the specification uses the phrase “in the body” to describe a diaphragm that is contained entirely within the body of the pump. Id., slip op. at 18. To confirm its claim construction, the court compared the first embodiment to the second, which did not have a diaphragm contained entirely within the body of the pump. In the second embodiment, the upper portion of the diaphragm was located outside of the body of the pump and the remaining portions were located inside of the body of the pump. The court noted that for the second embodiment the specification did not recite the “in the body” language, as it did for the first embodiment, but uses the phrase “mounted thereon” to describe the location of its diaphragm. Id.

As a result of its requiring the diaphragm to be entirely within the body of the pump, the district court granted summary judgment of non-infringement to TFY.

We agree with Cannon that the district court improperly added the limitation “entirely” in its interpretation of the claim limitation “diaphragm disposed in the body.” As an initial matter, we note that the term “in” is a simple, non-technical term, and that under its ordinary meaning, a “diaphragm disposed in the body” includes both diaphragms contained entirely and partially in the body. See Brown v. 3M, 265 F.3d 1349, 1352 (Fed. Cir. 2001) (recognizing that claim terms may not be technical terms of art, and do not require elaborate interpretation). For example, a trash bag is “in” a trashcan even though a portion of it is hanging outside of the trashcan.

Moving on from the question of plain meaning, we next address whether there is any justification for deviating from it. As discussed in Phillips v. AWH Corp., 415 F.3d 1303, 1316-17 (Fed. Cir. 2005), we may depart from the plain meaning of a claim term when the patentee has acted as a lexicographer or when the patentee has clearly limited the scope of the invention through a disclaimer in the specification or prosecution history. We conclude that neither situation occurred here.

As the district court recognized, the patent uses the phrase “in the body” in one instance to describe a diaphragm that is contained entirely within the body of the pump, and the phrase “mounted thereon” in another instance to describe a diaphragm that is contained partially within the body of the pump. These two cited instances, however, do not clearly indicate that the patentee intended to assign a more narrow definition to the phrase “in the body” than it would otherwise possess. See, e.g., Elekta Instrument S.A. v. O.U.R. Scientific Int’l, 214 F.3d 1302, 1307 (Fed. Cir. 2000) (for a patentee to act as its own lexicographer defining a claim term differently from its ordinary meaning, the specification must clearly indicate the patentee’s intent to do so)... [T]he specification uses different words to highlight the different ways that a diaphragm may be placed in the body of the pump. Moreover, contrary to TFY’s position, the specification unambiguously uses the phrase “in the body” in the “Summary of the Invention” section to refer to diaphragms that are contained both entirely and partially in the body of the pump. ’850 patent, col. 2, ll. 16-24. And the fact that the specification contains figures of embodiments that are both entirely and partially in the body is a strong indication that the claims were intended to encompass both.

Our review of the prosecution history also does not clearly indicate that the patentee intended to disclaim coverage in the claims for diaphragms that are not contained entirely within the body of the pump. See Omega Eng’g v. Raytek Corp., 334 F.3d 1314, 1325-26 (Fed. Cir. 2003) (requiring a disclaimer of subject matter in the prosecution history to be “clear and unmistakable”).

The case was remanded back to district court in light of the revised claim construction.

The hint for prosecutors is to be explicit if acting as a lexicographer, and to avoid, if possible, using a term or phrase in claims that was used to distinguish embodiments, as the wrong construction the district court held to in this case was understandable, even if not legally correct. It may be helpful to act explicitly as a lexicographer for something in a specification, so as to be able to point to that instance as a counterpoint to where ordinary definition was intended.