dissenting.
On Scimed’s motion for summary judgment, the district court, in faithful adherence to this court’s admonitions, decided the threshold issue of claim interpretation as a question of law. Advanced Cardiovascular Systems, Inc. v. Scimed Life Systems, Inc., 697 F.Supp. 354, 359, 8 USPQ2d 2002, 2005 (D.Minn.1988). There was no disputed question of material fact as to this issue. Id. The district court’s judgment was procedurally proper, and it requires appellate review on its merits. Thus I must dissent from the panel majority’s treatment of the issue as not amenable to summary resolution.
Both parties agreed that the sole question with respect to claim interpretation was the meaning of the words “formed integral” in representative claim 10:
10. In a dilating catheter assembly for use with a radiographic contrast liquid, a flexible tubular member and having proximal and distal ends, said tubular member having an inflatable annular portion formed integral therewith adjacent the distal end and a fitting carried by the proximal end and means permitting the introduction of a radiographic contrast liquid for inflating said inflatable annular portion and the removal of said radiographic contrast liquid to deflate said annular portion.
and the words “formed therein” in representative claim 11:
11. In a dilating catheter assembly, a first flexible tubular member formed of a flexible plastic material and serving as an inner catheter, a second flexible tubular member, said second tubular member encasing said first tubular member so that said first and second tubular members are coaxially aligned, said first and second tubular members having proximal and distal ends, said second tubular member having a balloon-shaped portion formed therein adjacent the distal end and a fitting carried by the proximal ends for permitting insertion and withdrawal of a fluid for inflating and deflating the balloon-shaped portion of the second tubular member.
(Emphases added.)
The district court, reviewing the undisputed facts of the specification and the prosecution history, held as a matter of law that “formed integral” and “formed therein” mean that the claims are directed to a single-piece construction of balloon and catheter tube. The court observed that the patent specification describes the balloon and catheter as a single tube of plastic material, and that the specification emphasizes that this unitary construction from a single tube is a principal advantage of the invention. The court quoted some of ACS’s many statements to this effect in the prosecution history: in distinguishing the Nozick reference, that applicant “has provided a balloon-shaped portion which is formed from the same tubular member” (emphasis added by the district court); in distinguishing the Taricco reference, that *1075“[i]n applicant’s novel construction, the balloon shaped portion is formed of the same tubular member which forms the tubular member of the catheter assembly”; in distinguishing the Gruntzig reference, that the ACS structure has “a balloon shaped portion formed therein” and “[s]uch an inflatable balloon like portion formed integral with the tubular member is an important feature of applicants’ invention”; that Gruntzig’s balloon is “a separate element” which needed to be cemented onto the tube, and “is certainly an inferior type of construction to applicants’ integral construction.” Advanced, 697 F.Supp. at 357-58, 8 USPQ2d at 2003-04.
The specification states that “the balloon-like portion 43 is formed by expanding that portion of [the outer tube] to its elastic limit”, describes the invention as “the outer tubular member having a balloon formed therein”, and states the advantages of avoiding the use of adhesive to attach a separate balloon. In distinguishing the Glover reference, ACS told the examiner that Glover’s heat shrinkable plastic catheter does not show applicants’ “novel structure” wherein the same heat-shrinkable plastic is used “for forming a balloon-shaped portion adjacent to the outer end” of the catheter.
The district court concluded that “these comments show that what ACS relied on for its distinctiveness was the fact that in its catheter, the balloon was not a separate element from the tube and did not require adhesives to join the two parts.” Id. at 360, 8 USPQ2d at 2006. The court observed that the examiner refused to allow what is now claim 10 until ACS reinstated the words “integral therewith” after “formed”. Id. at 357-58, 360, 8 USPQ2d at 2004, 2006. Referring to ACS’s proposed claim construction, the district court remarked:
It is significant to note that nowhere in the prosecution history of the patent does the definition that ACS urges appear. In its numerous attempts and opportunities to correspond with the Patent Examiner, ACS never refers to integral as meaning “completing and continuing the structure.” [emphasis in original]
Id. at 360, 8 USPQ2d at 2006.
Accompanied by detailed explanation of its analysis and reasons, the district court held that the claim terms “formed integral” and “formed therein” mean that the balloon and the catheter tube are made of the same tube.
The panel majority grounds its rejection of the district court’s judgment in part on the court’s having relied on statements in the prosecution history about the Nozick and Taricco references, without reading the entire references. The majority states that the district court erred in that it relied on “only part of the patent’s prosecution history”, based on the absence of the full text of these references from the materials provided to the district court.
The Nozick and Taricco references were cited during the patent examination, are discussed in the correspondence between the inventors and the examiner during patent prosecution (which correspondence was of record before the district court), and were referred to in Scimed’s motion for summary judgment. . ACS did not assert before the district court that the prosecution history was prejudicially incomplete. Further, ACS does not now state that it was precluded from providing these references to the district court. If there was a material omission from the record, it should have been raised before the district court. Jamesbury Corp. v. Litton Indus. Prods., Inc., 839 F.2d 1544, 1549, 5 USPQ2d 1779, 1783 (Fed.Cir.), cert. denied, — U.S.-, 109 S.Ct. 80, 102 L.Ed.2d 57 (1988).
ACS does not argue that the full texts of the omitted references raise any issue of material fact, or change anything at all. Indeed, ACS does not contradict Scimed’s statement that “There has never been any dispute that Nozick and Taricco disclose catheters with glued on balloons.” The panel majority’s reliance on this circumstance to vacate the district court’s judgment is unwarranted. Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 248, 106 S.Ct. 2505, 2510, 91 L.Ed.2d 202 (1986) (“Factual *1076disputes that are irrelevant or unnecessary-will not be counted.”) Further, it is inappropriate to criticize (and reverse) the district court for not studying documents that neither party provided to it.
Nor is it a fair criticism to hold, as a fatal flaw in the proceeding, that the district court “refused to consider ACS’s extrinsic evidence”. In a detailed opinion the district court gave persuasive weight to ACS’s statements in the specification and prosecution history, and did not adopt the positions of ACS’s expert witness and its inventors. The district court wrote that although “ACS might be able to call experts” (in addition to those already called) who would testify in support of ACS’s proposed claim interpretation, ACS is “es-topped by that history to urge a broader definition” than that set forth in the prosecution history. Advanced, 697 F.Supp. at 360, 8 USPQ2d at 2006. No error has been assigned to this statement of law.
The purpose of expert testimony is to provide assistance to the court in understanding, when the claims are technologically complex or linguistically obscure, how a technician in the field, reading the patent, would understand the claims. Snellman v. Ricoh Co., 862 F.2d 283, 287, 8 USPQ2d 1996, 2000 (Fed.Cir.1988), cert. denied, — U.S.-, 109 S.Ct. 3199, 105 L.Ed.2d 707 (1989). Directly to this point, ACS’s own witness Duane Dickens, testifying as an expert, stated that “integral” is used in its ordinary meaning, and is “not a common term of art in the catheter design field”. We reiterated in Howes v. Medical Components, Inc., 814 F.2d 638, 643, 2 USPQ2d 1271, 1273-74 (Fed.Cir.1987) that ordinary words in claims that “are not technical terms or terms of art” do not require expert evidence. See Id. at 644, 2 USPQ2d at 1274 (interpreting the words “joined” and “extending freely” in their ordinary meaning).
The district court not only received the expert’s testimony, but correctly held that this testimony could not change the meaning of the common terms used, as understood in light of the specification, the prosecution history, and the prior art. See General Elec. Co. v. United States, 572 F.2d 745, 751, 198 USPQ 65, 70 (Ct.Cl.1978):
Since the patentee is his own lexicographer, no genuine issue of fact as to the meaning of a claimed term can be found to exist where the meaning is made incontrovertibly clear elsewhere in the patent or in the file wrapper.
(Citation omitted).
In my view the district court correctly interpreted the claims. ACS argues before us that the court gave insufficient weight to Duane Dickens’ legal conclusion as to how he would interpret the claims, and to a dictionary definition of “integral”. This argument goes to the issue of correctness of the court’s conclusion of law, and does not negate the propriety of summary judgment of the question of claim interpretation when the facts are undisputed. Molinaro v. Fannon/Courier Corp., 745 F.2d 651, 654, 223 USPQ 706, 707 (Fed.Cir.1984).
Since the panel majority holds that material facts are in dispute, and thus that summary judgment was inappropriate, the issue of claim interpretation will presumably be determined by the jury, along with the issue of infringement.** With inade*1077quate guidance from this court as to how the district court erred in its legal analysis, our decision will raise fresh uncertainty as to the propriety of summary judgment on the issue of claim interpretation, and can only diminish use of this valuable tool,
The question of infringement was also decided on summary judgment, see Anderson v. Liberty Lobby, 477 U.S. 242, 251, 106 S.Ct. 2505, 2512, 91 L.Ed.2d 202 (1986) ("summary judgment should be granted where the evidence is such that it 'would require a directed verdict for the moving party”’) (quoting Sartor v. Arkansas Natural Gas Corp., 321 U.S. 620, 624, 64 S.Ct. 724, 727, 88 L.Ed. 967 (1944)); but since that judgment is also vacated, I have commented only on the legal issue of claim interpretation. The panel majority, however, has reproduced drawings of the accused device, taken from ACS’ brief. The drawings, which appear to be ACS's adaptations, relate to the question of infringement, literal or by equivalents. See, e.g., SRI Int’l v. Matsushita Elec. Corp. of Am., 775 F.2d 1107, 1118, 227 USPQ 577, 583 (Fed.Cir.1985) (in banc):
It is only after the claims have been construed without reference to the accused device that the claims, as so construed, are applied to the accused device to determine infringement, [emphasis in original]