The claims decide it
Patent infringement is measured against the claims, the numbered sentences at the end of the patent that define its scope. Generally, a product infringes a claim only if it includes every element of that claim, either literally or through a close equivalent. A competitor's product can look very similar and still fall outside the claims, or look different and fall inside them. The usual working tool is a claim chart, which maps each element of a claim to evidence about the accused product, often drawn from teardowns, manuals, or public technical documents. The meaning of key claim words is frequently disputed, and the court may have to decide it.
Checking your own position first
Before accusing anyone, look hard at your own patent. Is it in force, with maintenance fees paid? Who owns it on the USPTO record, and are there licenses that might already cover the competitor? Have you marked your own products, since failing to mark can limit damages for the period before the other side was notified? Also consider the prior art the other side might raise, because an accusation can prompt a validity challenge in court or at the USPTO. Pull the prosecution history as well, because arguments made to the examiner can narrow how the claims are read.
Deciding how to move
Sending a demand letter carries risk of its own. A letter that threatens litigation can allow the recipient to file first, asking a court to declare that it does not infringe, potentially in a court it prefers. It can also prompt a challenge to the patent's validity. Some owners start with a licensing approach, while others prepare a complaint before sending anything at all. We review the patent, the accused product, and your goals, whether that is stopping sales, collecting royalties, or negotiating a business arrangement, and help plan an approach that fits them.
