Patent questions,
plain answers.

A patent is a legal right granted by the government that lets an inventorinventorThe person who actually conceived the invention. Listed on the patent regardless of who owns it.Read more → exclude others from making, using, or selling their invention for a limited time — typically 20 years from the filing datefiling dateThe day the patent application was submitted to the USPTO. Sets the priority date for prior-art comparisons.Read more →. In exchange, the inventor publicly discloses exactly how the invention works. It's a deal: you teach the world your secret, and the government gives you a temporary monopoly.

Only what's written in the claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more → — the numbered paragraphs at the end of every patent. The abstractabstractA short summary at the front of the patent describing the invention. Not legally binding.Read more →, drawings, and description exist to explain the invention, but they have no legal force. If a competitor's product doesn't match every element of at least one claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more →, there's no infringementinfringementMaking, using, selling, or importing a patented invention without permission from the patent holder.Read more →. This is why 'what a patent doesn't cover' is just as important as what it does.

Utility patents (the most common kind) last 20 years from the application filing datefiling dateThe day the patent application was submitted to the USPTO. Sets the priority date for prior-art comparisons.Read more →, provided maintenance feesmaintenance feesPeriodic fees the USPTO charges to keep a granted utility patent in force (3.5, 7.5, 11.5 years post-grant). Miss one and the patent expires early.Read more → are paid at 3.5, 7.5, and 11.5 years. Design patents last 15 years from grant (no maintenance fees). After expiration, anyone can freely use the invention — which is why generic drugs, open-source designs, and expired tech become available to the public.

Patents protect inventions and functional processes (20 years, expires). Trademarks protect brand identifiers — names, logos, slogans — as long as they're in use (potentially forever). Copyrights protect creative expression — writing, music, art, software code — automatically at creation, for the author's life plus 70 years. A smartphone might involve all three: patents on the hardware, trademarks on the brand, and copyrightcopyrightLegal protection for original creative works (books, code, art). Automatic at creation. Different from patents, which protect inventions.Read more → on the operating system code.

Yes. Once a patent expires, the invention enters the public domainpublic domainThe status of an invention no longer protected by any IP rights — anyone can use it freely. Patents enter the public domain after expiration.Read more → and anyone can freely use, make, or sell it. This is exactly why generic pharmaceuticals exist — the active compound's patent has expired. Aspirin, the zipper, nylon, the telephone — all expired patents that the world now uses freely.

Prior artprior artEarlier patents, publications, or products that existed before this patent's filing date. Patent claims must be novel over the prior art.Read more → is any evidence that an invention was already publicly known before the patent application was filed. This includes earlier patents, academic papers, products already on the market, or even a YouTube video. If prior art exists that anticipates every element of a claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more →, that claim is invalid. Searching prior art is the core of patent litigationlitigationA lawsuit over patent infringement. Litigated patents often signal commercial importance.Read more → — and why patent examiners spend most of their time doing prior art searches.

ClaimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more → are the legal boundaries of a patent — think of them like a property line drawn in words. Each claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → is a single sentence (however long) that defines one version of the invention. Independent claims stand alone. Dependent claims add narrower limitations to an earlier claim. To infringe a patent, a product or process must match every element of at least one claim. Change one element and you may fall outside the claim.

An independent claimindependent claimA claim that stands alone — doesn't reference other claims. Defines the broadest scope of the invention.Read more → defines the invention on its own — it contains all the elements needed to stand alone. A dependent claimdependent claimA claim that adds a limitation to another claim. Narrower in scope but easier to enforce.Read more → references and narrows a previous claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → by adding more specific limitations. Dependent claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more → are narrower in scope but harder to invalidate, since they require proving all elements of the parent claim plus the additional limitation are in the prior artprior artEarlier patents, publications, or products that existed before this patent's filing date. Patent claims must be novel over the prior art.Read more →.

No — you can file 'pro se' (self-represented) at the USPTO. However, claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → drafting is highly technical and consequential: poorly written claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more → are either too narrow (easy to design around) or too broad (easy to invalidate). Most inventors who self-file end up with weak protection. A registered patent attorney or agent is worth the cost for anything commercially significant.

No. US patents only provide protection within the United States. For international protection, inventors use the PCT (Patent Cooperation Treaty) process, which lets you file one international application and then enter national phases in up to 150+ countries. Each country grants its own patent independently — there is no single 'world patent.'

A provisional applicationprovisional applicationA simplified, lower-cost patent application that establishes a filing date. Must be converted within 12 months.Read more → is a lower-cost, informal filing that establishes a priority datepriority dateThe earliest date used to compare the patent against prior art. Usually equals the filing date.Read more → without starting the 20-year clock. You have 12 months to file a full non-provisional application claiming that priority date. Provisionals let you say 'patent pending,' test the market, and refine your claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more → — but they never become patents on their own.

Search USPTO's patent database (patents.google.com is often more usable), the European Patent Office's Espacenet, or Google Patents. Search by keywords, inventorinventorThe person who actually conceived the invention. Listed on the patent regardless of who owns it.Read more → name, or assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →. Remember: a patent only blocks use during its term — if it's expired, you're free. PatentBrief explains landmark patents in plain English, which is a good starting point for understanding a technology space.