Lemelson is the assignee of approximately 185 unexpired patents and many pending patent applications of the late Jerome H. Lemelson. The patents at issue here generally involve machine vision and automatic identification bar code technology and are asserted to be entitled to the benefit of the filing date of two Lemelson patent applications filed in 1954 and 1956.

In its ruling, the CAFC went on to describe in some detail Lemelson's technique of generating a stream of continuation-in-part filings. Lemelson practically coined the patent game phrase "file early, file often".

Symbol also asserted that the patents were unenforceable for prosecution laches and inequitable conduct before the U.S. Patent and Trademark Office (“PTO”). Id. at 1151.

Previously, Lemelson had moved to dismiss the case, arguing that there was no case or controversy between the parties and that Symbol’s cause of action for prosecution laches failed to state a claim upon which relief could be granted. The district court concluded that there was a sufficient case or controversy, but it dismissed Symbol’s prosecution laches claim. Symbol Techs., Inc. v. Lemelson Med., Educ. & Research Found., No. 99-CV-0397 (D. Nev. Mar. 21, 2000) (“Symbol I”).

Symbol filed an interlocutory appeal to this court under 28 U.S.C. § 1292(b), and we agreed to consider “whether, as a matter of law, the equitable doctrine of laches may be applied to bar enforcement of patent claims that issued after an unreasonable and unexpected delay in prosecution even though the applicant complied with pertinent statutes and rules.” Symbol Techs., Inc. v. Lemelson Med., Educ. & Research Found., 277 F.3d 1361, 1363 (Fed. Cir. 2002) (“Symbol II”). We reversed the district court’s judgment, rejecting Lemelson’s arguments that prosecution laches was limited to claims arising out of interference proceedings and that the passage of the 1952 Patent Act with its provisions for filing continuation and continuation-in-part applications foreclosed the application of laches. Id. at 1365-66. We held instead that Symbol’s defense of prosecution laches was legally viable, and we remanded the case to the district court for further proceedings to determine the relevant facts.

Upon remand, the court conducted a bench trial from November 2002 to January 2003, followed by post-trial briefing that concluded in June 2003. In a decision issued in January 2004, the court held that Lemelson’s patents were indeed unenforceable due to prosecution laches, invalid for lack of enablement, and not infringed by Symbol’s products. First, although acknowledging that Symbol had not demonstrated that Lemelson intentionally stalled in securing the patents, the court stated that “unreasonable delay alone is sufficient to apply prosecution laches without the requirement that Lemelson intended to gain some advantage by the delay.” Symbol III, 30 F. Supp. 2d at 1156 (citing In re Bogese II, 303 F.3d 1362, 1369 (Fed. Cir. 2002)). The court also applied the doctrine of prosecution laches because Symbol had presented “strong evidence . . . of intervening private and public rights.” Id. at 1157. Accordingly, it held that “Lemelson’s 18 to 39 year delay in filing and prosecuting the asserted claims under the fourteen patents-in-suit . . . was unreasonable and unjustified and that the doctrine of prosecution laches renders the asserted claims unenforceable.” Id. at 1155.

We agree with Symbol that the court did not abuse its discretion in holding that Lemelson’s patents are unenforceable under the doctrine of prosecution laches. The doctrine of prosecution laches is an equitable defense, Symbol II, 277 F.3d at 1366 (quoting P.J. Federico, Commentary on the New Patent Act, 75 J. Pat. & Trademark Off. Soc’y 161, 215 (1993)), and we review the judgment of the district court on that issue for an abuse of discretion, Bridgestone/Firestone Research v. Auto. Club, 245 F.3d 1359, 1361 (Fed. Cir. 2001). This court has earlier held in this case that prosecution laches may render a patent unenforceable when it has issued only after an unreasonable and unexplained delay in prosecution. Symbol II, 277 F.3d at 1363, 1368. We did not set forth any firm guidelines for determining when such laches exists, but left this determination to the district court on remand, as the defense exists as an equitable doctrine. In so doing, however, we discussed precedent such as Woodbridge v. United States, 263 U.S. 50 (1923), and Webster Electric Co. v. Splitdorf Electrical Co., 264 U.S. 463 (1924), wherein the Supreme Court applied the doctrine of prosecution laches to render patents unenforceable. Although those cases involved a nine-and-a-half-year delay and an eight-year delay, respectively, the Court later held that the presumptive two-year time limit referred to in Webster was dictum because it was not directly applicable to the issue of laches on which the case was decided. Thus, there are no strict time limitations for determining whether continued refiling of patent applications is a legitimate utilization of statutory provisions or an abuse of those provisions. The matter is to be decided as a matter of equity, subject to the discretion of a district court before which the issue is raised.

There are legitimate grounds for refiling a patent application which should not normally be grounds for a holding of laches, and the doctrine should be used sparingly lest statutory provisions be unjustifiably vitiated. The doctrine should be applied only in egregious cases of misuse of the statutory patent system.

[R]efiling an application solely containing previously-allowed claims for the business purpose of delaying their issuance can be considered an abuse of the patent system. See Bogese, 303 F.3d at 1368-69 (discussing Ex parte Hull, 191 USPQ 157 (Bd. Pat. App. & Interfs. 1975)). In particular, multiple examples of repetitive refilings that demonstrate a pattern of unjustifiably delayed prosecution may be held to constitute laches.

So, prosecution laches is ultimately not a matter of statute, but of judicial discretion.

The Court laid out legitimate reasons for continuations: 1) divisionals; 2) unexpected advantages not previously appreciated; 3) broadening claim scope; 4) anything other than "unduly successive or repetitive". So, illegitimate continuations are rather like pornography: hard to define, but the Court knows it when it sees it.

Filing a divisional application in response to a requirement for restriction is one such legitimate reason for refiling a patent application. Given one’s entitlement to claim an invention in various ways, and the PTO’s practice of limiting its examination of an application to only one of what it considers to be several inventions, it cannot, without more, be an abuse of the system to file divisional applications on various aspects that the PTO has considered to be separate and distinct from each other. See 35 U.S.C. § 121 (2000); 37 C.F.R. § 1.142 (2005); see also Manual of Patent Examining Procedure §§ 803, 818 (8th ed., rev. 2 2004). That is so even when one defers the filing of a divisional application until just before the issuance of the parent application. Such action is expressly allowed by statute. 35 U.S.C. § 121. Moreover, one might legitimately refile an application containing rejected claims in order to present evidence of unexpected advantages of an invention when that evidence may not have existed at the time of an original rejection. Commonly, and justifiably, one might refile an application to add subject matter in order to attempt to support broader claims as the development of an invention progresses, although entitlement to an earlier filing date for any claimed subject matter may of course be necessary to avoid a statutory bar created by intervening events outlined in 35 U.S.C. §§ 102 and 103. One may also refile an application even in the absence of any of these reasons, provided that such refiling is not unduly successive or repetitive.

Patent grant duration changed from 17 years from issuance to 20 years from filing in 1995, rendering the Lemelson syndrome of stretching priority date back decades a thing of the past.