Patent Litigation Defense · Equitable Doctrines
Patent Laches
Can a patent owner wait years to sue and still recover full damages? SCA Hygiene Products v. First Quality Baby Products (Supreme Court 2017) answered yes — laches cannot bar damages within the 6-year statutory period. Here's what the doctrine still does and what it doesn't.
The rule post-2017
Laches cannot bar patent damages within the 6-year limitations period of 35 U.S.C. § 286. A defendant who benefited from years of patent-owner delay cannot use that delay to wipe out damages claims within the statutory window. But delay can still affect equitable relief — and equitable estoppel (a related but stronger defense) remains fully available.
SCA Hygiene Products v. First Quality Baby Products (2017)
How the law changed
Before SCA Hygiene
Federal Circuit (Aukerman 1992 en banc): 6+ years of delay created a rebuttable presumption of laches. Laches could bar damages even for infringement within the § 286 6-year window. Defendants regularly asserted laches based on prosecution and post-issuance delay.
After SCA Hygiene (2017)
Supreme Court (7-1): laches cannot bar legal damages within § 286's 6-year period. Congress already balanced the interests by enacting the 6-year limitations period; equitable laches cannot shrink the statutory window. Aukerman overruled on this point. 6 years of delay no longer creates a presumption that bars damages.
What laches still does after SCA Hygiene
Equitable relief (injunctions)
Courts retain discretion in the eBay four-factor test. A patent owner who waited 8 years before suing, during which the defendant built substantial infrastructure relying on the patent owner's silence, may face a court that considers that delay in weighing the balance of hardships or irreparable harm factors. Laches doesn't automatically deny injunctions post-SCA, but the facts underlying laches are relevant to equitable discretion.
Equitable accounting
Certain equitable accounting remedies (including disgorgement of profits in some theories) may be affected by laches because they are equitable in nature. SCA Hygiene specifically addressed the legal damages claim under § 284; the opinion left open questions about purely equitable relief.
Prejudice in eBay analysis
Economic prejudice — a defendant who invested millions building a business in part relying on a patent owner's prolonged silence — is a legitimate factor in the eBay balance of hardships. Courts can and do consider this without calling it 'laches.'
Legal damages within 6 years
Laches categorically cannot bar compensatory patent damages (§ 284) for infringement within the 6 years before the complaint. This is the core holding of SCA Hygiene.
Enhanced damages (willfulness)
Delay in filing suit does not convert non-willful infringement into willful infringement — a defendant who continues infringing after receiving notice may be willful, but the patent owner's delay in filing suit has no bearing on the defendant's state of mind.
Related defense
Equitable estoppel vs. laches
Equitable estoppel is a separate and more powerful defense that survived SCA Hygiene intact. It can bar all relief — including damages — but requires more than delay.
Laches (post-SCA Hygiene)
- ·Unreasonable delay in asserting rights
- ·Material prejudice to defendant
- ·Cannot bar damages within § 286 6-year period
- ·May affect equitable relief discretion
Equitable estoppel (A.C. Aukerman)
- ·Patentee communicated it would not enforce rights (affirmative act OR misleading silence)
- ·Infringer reasonably relied on that communication
- ·Material harm from reliance
- ·Can bar ALL relief including damages — even within 6-year period
FAQ
Patent laches questions
What is patent laches and what did SCA Hygiene v. First Quality hold?
Patent laches is an equitable defense against a patent infringement claim based on the patent owner's unreasonable delay in filing suit, to the prejudice of the alleged infringer. Before 2017, laches could bar a patent owner from recovering damages even for infringement within the 6-year statutory window under 35 U.S.C. § 286. SCA Hygiene Products Aktiebolag v. First Quality Baby Products, LLC (Supreme Court 2017) changed this: the Court held, 7-1, that laches cannot bar a legal claim for patent infringement damages that accrued within the 6-year limitations period. The Court reasoned that laches is an equitable defense that operates in the absence of a statutory limitations period — once Congress sets a limitations period (§ 286's 6 years), laches cannot shrink it further. The decision overruled the Federal Circuit's A.C. Aukerman Co. v. R.L. Chaides Construction (1992 en banc) ruling to the extent Aukerman permitted laches to bar damages within the statutory period.
Does laches still apply in patent cases after SCA Hygiene?
Yes, in limited ways. After SCA Hygiene (2017): (1) Laches cannot bar legal damages for infringement within the 6-year statutory period under § 286. (2) Laches MAY still affect equitable relief — courts retain discretion to consider delay in the eBay four-factor injunction analysis, particularly the 'balance of hardships' factor. A patent owner who waited 8 years before suing, during which the defendant built a manufacturing plant based partly on the patent owner's silence, may find that the court exercises discretion to deny a permanent injunction on equitable grounds even after winning on liability. (3) Laches may still affect equitable accounting remedies. (4) Equitable estoppel — a separate defense — is still available and can bar all relief, including damages. Unlike laches (which rests on delay alone), equitable estoppel requires: (a) the patent owner communicated (expressly or by silence) that it would not assert its rights; (b) the infringer reasonably relied on that communication; (c) the infringer was materially harmed by the reliance.
What is the difference between laches and equitable estoppel in patent law?
Laches and equitable estoppel are related but distinct defenses. Laches requires: (1) unreasonable delay by the patentee in asserting rights after knowing of infringement; and (2) material prejudice to the defendant (evidentiary prejudice — lost witnesses, faded memories — or economic prejudice — investments made in reliance). After SCA Hygiene, laches cannot bar damages within 35 U.S.C. § 286's 6-year period. Equitable estoppel (A.C. Aukerman, 1992 en banc) requires all the laches elements PLUS a separate element: the patentee must have communicated something — by affirmative act or misleading silence — that led the infringer to reasonably believe the patentee had abandoned or would not assert its patent rights. The defendant must have relied on that communication in a way that caused material harm. Equitable estoppel, if proven, can bar ALL relief — including damages that would otherwise fall within § 286. It is a stronger defense than laches but has an additional requirement. Courts may consider both defenses simultaneously; the elements often overlap in the facts.
What is the 6-year patent damages limitation period?
35 U.S.C. § 286 provides that 'no recovery shall be had for any infringement committed more than six years prior to the filing of the complaint or counterclaim for infringement in the action.' This is a rolling 6-year window — the patent owner can recover damages for infringement that occurred within the 6 years immediately before the lawsuit was filed. Infringement that occurred more than 6 years before the complaint is not compensable, regardless of when the patent owner discovered it. The § 286 period is a statute of limitations, not a statute of repose — it does not extinguish the underlying patent right, only the damages claim for older infringement. A patent that issues today can be infringed in 15 years, and at that point the owner can sue and recover 6 years of back damages from the suit date forward. SCA Hygiene confirmed that laches cannot shrink this 6-year window; defendants cannot use delay as a basis to bar recovery for infringement within it.
Why might a patent owner delay enforcing a patent?
Patent owners delay enforcement for many legitimate reasons, and post-SCA Hygiene, delay within the 6-year § 286 period no longer creates a laches defense. Common legitimate reasons: (1) Building the infringement case — collecting evidence, acquiring samples of the accused product, obtaining claim construction positions. (2) Business relationship concerns — the infringer may be a customer, supplier, or partner, and the patent owner is trying to negotiate a license before suing. (3) Financial constraints — patent litigation is extremely expensive ($3M–$10M+ for a complex case through trial); patent owners may wait until they have resources. (4) Claim scope uncertainty — waiting for clearer claim construction guidance from related cases or for the patent to strengthen through related proceedings. (5) Portfolio strategy — coordinating enforcement with multiple patents or multiple infringers. Delay beyond 6 years before suit may affect equitable relief discretion and opens up an equitable estoppel defense, so patent owners should document the reasons for any delay in a contemporaneous file.