What Happened
Patent claims are the numbered sentences at the end of a patent that define what's protected. Everything else—the description, drawings, examples—is context. The claims are the legal boundaries.
Why It Matters
Infringement is determined by comparing the accused product to the claims, not to the whole patent. If your product has every element of a claim, you infringe. If it's missing even one element, you don't.
Claim language matters enormously. "Comprising" means "including but not limited to"—other elements can be added without avoiding infringement. "Consisting of" means exactly those elements—nothing more. Small word choices have big consequences.
Claims can be broad or narrow. Broad claims cover more but are more vulnerable to invalidity challenges. Narrow claims are harder to design around but easier to get granted. Good patents have both—broad claims for maximum coverage and narrow fallback claims for validity.
What You Should Know
If you're reading patents, focus on the claims. The description helps interpret them, but the claims define the protection.
If you're drafting patents, invest heavily in claim drafting. This is where the value is created. Test claims against competitor products. Anticipate prior art. Think about enforcement.
If you're evaluating patent risk, do a proper claim chart analysis. Map each claim element to your product. Don't rely on general impressions.
Claims are the patent. Understand them.