concurring in the result.
I believe that (1) application of the reverse doctrine of equivalents presents a factual (not a legal) issue; (2) there is a question whether MEI’s device literally infringes the claims in suit; and (3) the reverse doctrine of equivalents and prosecution history estoppel having been raised as a defense to literal infringement, there is sufficient doubt about the relevant facts and circumstances to call for a full trial and to make erroneous the grant of summary judgment below. In a comparable recent case, in which there was similar doubt as to the relevant facts bearing on equivalents, we overturned a summary judgment and directed that a trial be had. Palumbo v. Don-Joy Co., 762 F.2d 969, 973-77, 226 USPQ 5, 7-10 (Fed.Cir.1985). I concur with the majority of the court that we should do the same here, especially since the District Court seems to have treated application of equivalents as essentially a legal issue.
But I do not agree that this court should decide on this appeal the issue of prosecution estoppel against appellee as a matter of law. Rather, that question, too, should be remitted for trial, as was done with respect to the prosecution history questions in Palumbo, supra, 762 F.2d at 976-77, 226 USPQ at 10, and in Lemelson v. TRW, Inc., 760 F.2d 1254, 225 USPQ 697 (Fed.Cir.1985). In my view, the meaning and impact in this case of the cited prosecution history is sufficiently uncertain that explanatory testimony and fuller ventilation could well be helpful.
I add explicitly that (a) I believe that the trial court dispensed with a jury trial here for no other reason than that it wrongly concluded that there were no disputed factual issues needing any type of trial, (b) there never has been in this case, and is not now, any question relating to the so-called “complexity exception” to the right to a jury trial, (c) the “complexity exception” issue was neither raised nor briefed nor argued by either side in this case, and (d) it would be wholly gratuitous, unnecessary, and inappropriate to decide that issue in this case.