Landmark Patent Cases

The question

Can a combination of known elements be obvious to try — even without a specific teaching or suggestion to combine them?

The holding

Yes. The Supreme Court rejected the rigid 'teaching-suggestion-motivation' (TSM) test the Federal Circuit had used to find combinations non-obvious. Combinations of existing elements are obvious when there are recognizable incentives to combine them and when the combination would have been obvious to try.

What it changed

KSR dramatically increased the number of patent claims invalidated as obvious. The 'obvious to try' standard means that patents on incremental improvements — combining two known technologies — face much harder scrutiny. Post-KSR, examiners and courts use a flexible, common-sense approach to obviousness rather than requiring a specific prior art suggestion to combine.

The question

Who interprets the meaning of patent claim terms — the judge or the jury?

The holding

Judges, not juries, construe (interpret) the meaning of patent claims. Claim construction is a matter of law, decided by the judge in a 'Markman hearing' before trial.

What it changed

Markman hearings became a pivotal battleground in patent litigation. The outcome of a Markman hearing — what the claims mean — often determines whether infringement is found. Parties spend enormous resources briefing claim construction. The Federal Circuit reviews claim construction de novo (from scratch), which led to high reversal rates for years.

The question

Is a patent owner automatically entitled to a permanent injunction once infringement is proven?

The holding

No. A patent owner seeking a permanent injunction must satisfy the traditional four-factor equitable test: (1) irreparable injury; (2) inadequacy of money damages; (3) balance of hardships favoring the plaintiff; and (4) no harm to the public interest.

What it changed

eBay eliminated the near-automatic injunction rule that had made patent litigation extremely powerful for non-practicing entities (patent trolls). Before eBay, a judgment of infringement almost guaranteed an injunction — forcing a settlement at any price. After eBay, operating companies infringing patents of NPEs (who don't make products and can't claim irreparable harm from competition) rarely face injunctions. Only parties who actually compete with infringers typically get them.

The question

When can a court award up to treble (3x) damages for willful patent infringement, and what standard applies?

The holding

Enhanced damages under § 284 should be reserved for 'egregious cases of misconduct' — deliberate or wanton infringement. Courts may award enhanced damages based on the circumstances at the time of infringement; a defendant cannot escape liability solely by raising a post-hoc invalidity defense.

What it changed

Halo relaxed the prior Seagate standard, which required the plaintiff to prove both subjective recklessness and objective recklessness by clear and convincing evidence. Now, a finding that the defendant knew of the patent and deliberately infringed can support enhanced damages, even if the defendant had some invalidity defense.

The question

Does a patent owner's sale of an authorized product exhaust its patent rights downstream — even for method patents?

The holding

Yes. Once a patent owner (or licensee) sells an authorized product that embodies the essential features of a patent — including a method patent — the patent rights are exhausted. The buyer can use, resell, and incorporate the product without infringing the patent.

What it changed

Quanta significantly limited the ability of patent holders to control downstream uses of products they have already sold or licensed. It applied exhaustion to method patents (not just product patents), closing a loophole chip manufacturers had tried to exploit by licensing component makers but then asserting method patents against customers who incorporated those components.

The question

How indefinite does a patent claim have to be before it is invalid? What is the correct legal standard?

The holding

A patent claim is indefinite under § 112(b) if it fails to 'inform, with reasonable certainty, those skilled in the art about the scope of the invention.' This is a tougher standard than the prior Federal Circuit rule (which only invalidated claims that were 'insolubly ambiguous').

What it changed

Nautilus strengthened the definiteness requirement, making it easier to challenge vague claim terms. Common targets: claims using 'substantially,' 'about,' 'approximately,' or relative terms without defined reference points. Claims with functional language that doesn't clearly distinguish what is and isn't covered are now more vulnerable.

The question

When a patent applicant narrows a claim during prosecution (to overcome a rejection), can they later argue the narrowed claim covers territory they surrendered?

The holding

No — but the complete bar rule is wrong. When a patentee narrows a claim by amendment, there is a presumption (rebuttable) that they surrendered all territory between the original and amended claim scope. The patentee can rebut this presumption by showing the narrowing was unrelated to patentability.

What it changed

Prosecution history estoppel is the doctrine that prevents patentees from recapturing, through the doctrine of equivalents, claim scope they surrendered during prosecution. Festo established that narrowing amendments create a presumptive bar — but it's rebuttable. This incentivizes careful claim drafting: don't narrow claims unless you have to, and document why any narrowing is unrelated to patentability.

The question

Can software that performs an abstract financial intermediation function be patented simply by implementing it on a computer?

The holding

No. Abstract ideas implemented on a generic computer are not patentable. The two-step Mayo/Alice test: (1) does the claim recite an abstract idea, law of nature, or natural phenomenon? If yes, (2) does it contain an 'inventive concept' that transforms the abstract idea into a patent-eligible application?

What it changed

Alice invalidated thousands of software and business-method patents and made the subject-matter eligibility of software patents the central battleground in patent prosecution. The USPTO rejections applying Alice caused software patent grant rates to plummet and forced applicants to draft claims emphasizing specific technical improvements rather than functional outcomes.