dissenting.
The majority affirms the Final Determination of the United States International Trade Commission (“Commission”) that the Intervenors do not infringe United States Patent Nos. 5,860,267 (the “'267 patent”), 6,023,907 (the “'907 patent”), and 6,182,410 (the “'410 patent”), which claim systems and methods of joining floorboards and which are owned by Aloe.1 The majority concludes that the Commission correctly construed the claims at issue *1376as requiring “play,” or space between a locking groove on a first panel and a locking element of a panel adjacent to the first panel. The Commission’s determination of non-infringement resulted from that claim construction because none of the Interve-nors’ accused products exhibit the required play. I respectfully dissent. I do so because I am unable to agree with the majority that play is a limitation of the claims at issue.
The majority arrived at the conclusion that the asserted claims require play by relying on statements made by the paten-tee in the '907 patent specification.2 The statements identified in the majority’s opinion describe play and criticize prior art flooring systems. The majority concludes that these statements compel it to limit the scope of the claims. It further relies on the prosecution history of a parent patent common to the asserted patents, United States Patent No. 5,706,621 (the “'621 patent”). It does so for confirmation of its decision to restrict the asserted claims.
It is always important to bear in mind controlling claim construction principles. Claim interpretation begins with the intrinsic evidence, i.e., the claims themselves, the written description, and, if in evidence, the prosecution history. CCS Fitness, Inc. v. Brunswick Corp., 288 F.3d 1359, 1366 (Fed.Cir.2002). The terms used in a claim bear a “heavy presumption” that they have the ordinary meaning that would be attributed to those words by persons skilled in the relevant art. Id. at 1366. An accused infringer may overcome this “heavy presumption” and narrow a claim term’s ordinary meaning, but it may not do so by pointing to a preferred embodiment disclosed in the specification or prosecution history. Id. In my view, the majority has allowed the accused infringer to narrow the scope of the claims to a preferred embodiment disclosed in the specification.
I begin with the language of the claims. As the majority points out, the asserted claims do not expressly recite play. On appeal, the Intervenors argue that, despite this omission, the claim terms “displace” and “disassemble” require that the mechanical connections between the floorboards have play.3 They further argue that the claim terms “locking member,” “locking groove,” “locking strip,” and “locking element” are means-plus-function terms and that the only corresponding structure disclosed in the specification is a flooring system that includes play. I only analyze the disputed claim terms. Vivid Techs., Inc. v. American Science & Eng’g, Inc., 200 F.3d 795, 803 (Fed.Cir.1999) (“[Ojnly those terms need be construed that are in controversy, and only to the extent necessary to resolve the controversy”).
I turn first to the term, “displace,” which is recited in claim 1 of the '907 patent in the two following phrases: “the two panels are ... displaceable in relation to each other in the direction of the adjacent joint edges” and “displacing the new panel relative to the second panel.”4 '907 *1377patent, col. 10, II. 50 & 65-66. The ordinary meaning of the term “displace” is “to remove from the usual or proper place.” Merriam Webster’s Collegiate Dictionary 335 (10th ed.1999); See Texas Digital Sys., Inc. v. Telegenix Inc., 308 F.3d 1193, 1202 (Fed.Cir.2002) (holding that a court may consult a dictionary, encyclopedia, or treatise to help inform the court of the ordinary meaning of a word). In the patents’ context, when one displaces a floorboard, one slides the board relative to an adjacent board. Thus, the ordinary meaning of this term is not restricted to flooring systems that have play.
Regardless, a court may restrict the ordinary meaning of a claim term in one of four ways. CCS Fitness, 288 F.3d at 1366. First, a claim term will not receive its ordinary meaning if the patentee acted as his or her own lexicographer and clearly set forth a definition of the disputed term in either the specification or prosecution history. Id. at 1366. Second, a claim term also will not receive its ordinary meaning if the term “chosen by the paten-tee so deprives the claim of clarity” as to require resort to other intrinsic evidence for a definite meaning. Id. at 1367. Third, if the patentee phrased a claim term in means-plus-function format, the term will only cover the corresponding structure disclosed in the specification, as well as equivalents thereto. Watts v. XL Sys., Inc., 232 F.3d 877, 880-81 (Fed.Cir.2000). Finally, and most relevant to this case, a claim term will not carry its ordinary meaning if the intrinsic evidence shows that the patentee limited the scope of the claims. Id. at 882 (“One purpose for examining the specification is to determine if the patentee has limited the scope of the claims.”); Bayer AG v. Elan Pharm. Research Corp., 212 F.3d 1241, 1252 (Fed.Cir.2000) (stating that the prosecution history may only be used to restrict the claims if it includes a clear and unmistakable exclusion or restriction of the claims).
The Intervenors, on appeal, do not argue that Alloc set forth a definition of the term “displace” in either the specification or the prosecution history requiring us to deviate from the plain meaning of the term. They also do not argue that the term “displace” deprives the claims of clarity requiring resort to other intrinsic evidence for a definite meaning. Additionally, there is no contention that the term “displace” is expressed in means-plus-function language. Rather, the parties dispute whether the patentee limited the meaning of the term through statements made in the specification of the '267, '907, and '410 patents or in the prosecution history of the '621 patent. I remain unconvinced that the intrinsic evidence shows that Alloc limited the scope of the claims.
The majority relies on several statements in the patent specification to limit the claims to systems and methods of joining floorboards that have play. In my view, the majority erroneously imports a play limitation into the claims from the common specification of the three patents at issue. Doing so contravenes our well-established doctrine prohibiting the addition of such limitations. Comark Communications v. Harris Corp., 156 F.3d 1182, 1186 (Fed.Cir.1998). As we have noted in the past, there is a very fine line between “examining the specification [ ] to determine if the patentee has limited the scope of the claims,” see Watts, 232 F.3d at 882, and improperly importing a limitation from a patent specification into a claim, see Comark, 156 F.3d at 1186. A specification may only be used to limit a claim if a patentee has disavowed or disclaimed scope of coverage, by using words or expressions of manifest exclusion or restriction, representing a clear disavowal of claim scope. Teleflex, Inc. v. Ficosa N. Am. Corp., 299 F.3d 1313, 1325 (Fed.Cir.2002). In my view, the specification does *1378not include any expressions of manifest restriction requiring us to limit the claims.
The majority identifies three statements in the specification where play is discussed. The first statement provides, in pertinent part, as follows:
Thus, the invention provides a system for making a joint along adjacent joint edges of two building panels, especially floor panels, ... said system being characterized in ... that the panels, when joined together, can occupy a relative position in said second direction where a play exists between the locking groove and a locking surface on the locking element that is facing the joint edges and is operative in said second mechanical connection....
'907 patent, col. 8, II. 59-67 & col. 4, II. 15-19. This statement does not evince an expression of manifest restriction to systems or methods of joining floorboards that have play, nor is it a clear disavowal of claim scope. The statement does not describe a method of joining floorboards. Rather, it refers to just one embodiment, specifically, a system of floorboards that has play. Therefore, it cannot be used to limit the methods claimed in the '907 and '267 patents. It also cannot be used to limit the systems claimed in the '410 patent because the statement employs the word “can.” “Can” and “may” are commonly used by patentees to show that a limitation is permissive. Even if we interpret the word “can” to mean “are able to,” as the administrative judge interpreted it, the statement still is permissive and does not require that play exist between two floorboards.
We have, in the past, relied on statements made in a patent specification to restrict a claim’s scope. Such statements have, for example, identified a structure and stated that the structure was employed “for all embodiments of the present invention contemplated and disclosed herein.” SciMed Life Sys., Inc. v. Advanced Cardiovascular Sys., Inc., 242 F.3d 1387, 1343 (Fed.Cir.2001). The statements, however, have always been clear expressions of manifest exclusion or restriction. We have also found claims to be limited in cases where a patentee described only those embodiments that included a particular feature and expressly distinguished the invention over prior art based on the fact that the prior art lacked the identified feature. See O.I. Corp. v. Tekmar Co., 115 F.3d 1576, 1581 (Fed.Cir.1997).
In this case, the statement from the '907 patent specification is not a clear expression of manifest restriction that requires all embodiments to have play or that limits the claims to only those systems of floorboards that have play. Neither is this a case, as the majority suggests, where only one embodiment is disclosed and where the patentee criticized prior art because it does not include play. I think the majority’s contention that the patentee criticized prior art systems without play is misplaced. The prior art reference, to which the majority refers, Swedish reference SE 450,141, discloses panels that are held together by mechanical clips on the underside of the panels. The '907 patent also discusses prior art systems that use glue to hold adjacent panels together. '907 patent, col. 2. II. 25-27. The patent criticizes these systems for several reasons, but most importantly because their panels are not displaceable once they have been assembled and cannot be disassembled without being damaged. Id. at col. 3, II. 1-21. These systems are not displaceable and cannot be disassembled because their panels are mechanically or chemically held together, not merely because there is no space between the locking groove and locking element. The '907 patent does not criticize these prior art systems, which use mechanical clips and glue, for lacking play. The patentee’s statements do not evidence *1379an attempt to disclaim systems and methods of joining floorboards that do not have play.
The second statement cited by the majority is as follows:
In order to permit raking up previously laid, joined floor panels in a simple way, a preferred embodiment of the invention is characterized in that when the groove panel is pressed against the strip panel in the second direction and is turned anglularly [sic] away from the strip, the maximum distance between the axis of rotation of the groove panel and the locking surface of the locking groove closest to the joint edges is such that the locking element can leave the locking groove without contacting the locking surface of the locking groove. Such a disassembly can be achieved even if the aforementioned play between the locking groove and the locking surface is not greater than 0.2 mm.
’907 patent, col. 5, II. 18-29. This statement is made with respect to a preferred embodiment. The preferred embodiment relates to the disassembly of a floorboard system that has play of 0.2mm or more.5 As noted, disassembly is not required by most of the asserted claims, and statements, such as this one, relating to disas-sembly do not inform our construction of the term “displace.”6
Since two of the asserted claims require disassembly through unlocking adjacent panels or through a locking element leaving a locking groove, the parties dispute the meaning of disassembly. In my view, it also does not require a play limitation. Although the specification refers to play with respect to disassembly, the reference is in a preferred embodiment that describes how to take up floor panels in a simple way where the locking groove does not contact the locking surface of the locking groove. '907 patent, col. 5, II. 18-29. The specification also- discloses that the panels can be quickly and conveniently disassembled without reference to play. Id. at col. 4, II. 51-54. The second statement, therefore, does not limit the disputed claim terms.
The third statement cited by the majority is as follows:
When the panels 1 and 2 are joined together, they can however occupy such a relative position in the direction D2 that there is a small play A between the locking surface 10 and the locking groove 14. This mechanical connection in the direction D2 allows mutual displacement of the panels 1, 2 in the direction of the joint, which considerably facilitates the laying and enables joining together the short sides by snap action.
'907 patent, col. 7, II. 38-45. This statement should not be considered out of context. It should be read in light of the paragraph before it, which describes in some detail the locking members but does not describe play. Again, this statement uses the permissive “can,” which suggests that play is not required. In addition, it uses the word “however,” suggesting that the configuration is an alternative to the *1380configuration described in the preceding paragraph. None of these statements utilize expressions of manifest restriction; therefore, they do not restrict the claims.
Finally, I turn to the claim terms “locking member,” “locking groove,” “locking strip,” and “locking element.” The Inter-venors argue that these are means-plus-function terms because they do not recite sufficient structure to maintain the presumption that they are not 35 U.S.C. § 112, ¶ 6 claim terms. The word “means” is not used with respect to these terms in claims 19, 23, and 39 of the '267 patent or in claims 1 and 2 of the '907 patent, and therefore there is a presumption that section 112, ¶ 6 does not apply.7 Personalized Media Communications, LLC v. Int’l Trade Comm’n, 161 F.3d 696, 703-04 (Fed.Cir.1998) (“[T]he failure to use the word ‘means’ creates a presumption that § 112, ¶ 6 does not apply ... ”). The presumption can only be overcome if the Interve-nors show that the claimed term “fails to recite sufficiently definite structure or else recites a function without reciting sufficient structure for performing that function.” CCS Fitness, 288 F.3d at 1369 (internal quotes omitted).
In this case, “to lock” is a function. However, a “lock” is a structure that took its name from its function. Personalized Media, 161 F.3d at 703 (“Many devices take their names from the functions they perform. The examples are innumerable, such as ‘filter,’ ‘brake,’ ‘clamp,’ ‘screwdriver,’ or ‘lock.’ ”). The term “member,” as Alloc contends, means “a constituent part of a whole.” Merriam Webster’s Collegiate Dictionary 12A (10th ed.1999). It is well known in the mechanical arts that a lock typically has several parts that interconnect. Therefore, a locking member refers to a part of a lock and recites structure rather than function. The same is true for the terms “locking groove,” “locking strip,” and “locking element.” As such, these terms maintain their ordinary meanings and do not require play.
The majority also relies on the prosecution history of the '621 patent application to support its conclusion that the '907 patent specification limits the asserted claims. I do not think, however, that the prosecution history evidences a clear and unmistakable exclusion or restriction of the claims, as required by our precedent. Bayer, 212 F.3d at 1252. Specifically, the majority relies on statements made by the inventor during prosecution of the '621 patent distinguishing the claims over a pri- or art reference called Trotter. The '621 patent claims that were pending at the time the statements were made (claims 1-20) included an express limitation of play. Therefore, the statement by the patentee that “Trotter also does not teach or suggest a system wherein two panels, when *1381joined together, occupy a relative position where a play exists” is an accurate statement and does not relate to claims that do not include the same element. Statements such as these made during the prosecution of a parent application can only apply to continuation applications if the parent and child patents contain the same claim limitations. Biovail Corp. Int’l v. Andrx Pharms., Inc., 239 F.3d 1297, 1301 (Fed.Cir.2001) (“When multiple patents derive from the same initial application, the prosecution history regarding a claim limitation in any patent that has issued applies with equal force to subsequently issued patents that contain the same claim limitation.”); see Desper Prods., Inc. v. QSound Labs, Inc., 157 F.3d 1325, 1339 n. 6 (Fed.Cir.1998) (holding that this rule also applies to divisional applications). These particular statements, however, cannot apply to the '907, '267, or '410 patent claims because they do not share the express play limitation that was in claim 1 of the '621 patent at the time the statements were made. Advanced Cardiovascular Sys., Inc. v. Medtronic, Inc., 265 F.3d 1294, 1306-07 (Fed.Cir.2001) (“Medtronic provides no plausible reason why the prosecution histories of either the '273 or '548 patents are relevant to the construction of claim 3 of the '233 patent. Notably, there are no common claim terms in dispute. Indeed, the present case involves the absence of a claim term.”).
After the Examiner of the '621 patent application issued a Notice of Allowance, the inventor realized that he could remove the play limitation and his claims would still be novel over the prior art. This led him to add claims 21-23 to the '621 patent application. These claims excluded the limitation of play. The response to the Examiner’s Office Action stated with respect to claim 22:
New independent claim 22 is substantially the same as independent claim 1 except that it does not define the play that exists between the locking groove and the locking surface. As such, displacement of the panels is still facilitated in a direction along the joints which is what is believed to be meant by the Examiner’s Statement of Reasons for the indication of allowable subject matter. Accordingly, claim 22 is also patentable over the cited prior art.
These statements do not represent a clear and unmistakable disclaimer or restriction to systems that have play. To the contrary, they suggest that claim 22 does not require play. In fact, the doctrine of claim differentiation suggests that two claims that are identical except for one element presumptively differ in scope. Kraft Foods, Inc. v. Int’l Trading Co., 203 F.3d 1362, 1368 (Fed.Cir.2000) (stating that claim differentiation creates a presumption that each claim in a patent has a different scope). In this case, claim 1 and claim 22 are identical except that claim 22 excludes the play limitation. This suggests that they do in fact differ in scope. Moreover, the phrase, “play that exists,” which concerns the majority, merely mirrors the language in claim 1 of the '621 patent and does not indicate that play in fact exists as an element of claim 22.
Even if these last statements do place a limit on claim 22, this limitation would not apply to the '907, '267, or '410 patent claims because they do not share a common term that has been limited. Instead, the patentee effectively imported a limitation into claim 22 through the prosecution history. Advanced Cardiovascular, 265 F.3d at 1306-07. The same limitation is not necessarily imported into to the subsequent claims in a related patent.
In light of this claim construction, I would vacate the Final Determination of the Commission that the Intervenors do not infringe the '267, '907, and '410 patents. In addition, I would remand the *1382case to the Commission for further proceedings regarding infringement, validity, and domestic industry. Since the majority rejects this claim construction, I do not address those issues. To do so would be a mere academic exercise.
For the foregoing reasons, I respectfully dissent.
. As the majority has done, in the interest of clarity, I refer to Alloc, Inc., Berry Finance N.V., and Valinge Aluminium, AB, collectively as Alloc.
. Again, as the majority has done, I refer only to the '907 patent specification throughout this opinion, except where otherwise indicated. The patent specifications of the '267, '907, and '410 patents are identical.
. While many of the claims require "displacement,” most of the asserted claims do not require "disassembly.” In fact, only claims 1 and 39 of the '410 patent require that adjacent panels be able to "unlock” or that a locking element be able to "leave” a locking groove. The word "disassemble” does not appear in the claims.
.The term "displace” is also employed in claims 19, 23, and 39 of the '267 patent and claims 1, 26, and 39 of the '410 patent. Claim 1 of the '907 patent, however, is representative of these claims.
. Even if play is required, as the majority holds, it should be defined for purposes of disassembly as a space of 0.2mm or more between a locking groove on a first panel and a locking element of a panel adjacent to the first panel. With respect to displacement, no limit on the amount of play is disclosed in the specification. As such, play should be defined as a space greater then 0mm that allows displacement. The majority points to no evidence, much less substantial evidence, that supports the Commission's finding of no literal infringement. 5 U.S.C. § 706.
. For example, the method recited in claim 1 of the '907 patent does not include disassem-bly as one of the claimed steps. Only claims 1 and 39 of the '410 patent claim an edge lock and a flooring system that allow disassembly of adjacent panels.
. Claims 1, 26, and 39 of the '410 patent do use the word ''means.” See Personalized Media, 161 F.3d at 703 (stating that the word "means” in a patent claim triggers a presumption that the element is expressed as a means-plus-function limitation). Claim 1 is representative and recites the function as (1) "forming a first mechanical connection for locking said adjacent edges to each other in a vertical direction” and (2) "forming a second mechanical connection for locking said adjacent edges to each other in a horizontal direction at right angles to said edges.” '410 patent, col. 10, II. 42-46. The structure disclosed in the specification that corresponds to this function is the tongue and groove to form the first mechanical connection for locking the edges in the vertical direction and the locking strip and locking groove to form the second mechanical connection for locking the edges in a horizontal direction. Id. at col. 1, II. 36-37. See B. Braun Medical v. Abbott Labs., 124 F.3d 1419, 1424. (Fed.Cir.1997) (“Structure disclosed in the specification is 'corresponding' structure only if the specification or prosecution history clearly links or associates that structure to the function recited in the claim.”). These structures, as discussed below, do not require play.