Legal Definitions - literal infringement

Literal infringement occurs in patent law when an accused product or process contains every single element described in at least one claim of an existing patent. It means there is a direct, "word-for-word" match between the language used in the patent's claims and the features or steps present in the allegedly infringing item or method. Essentially, the accused item or process directly incorporates each and every component or step outlined in the patent's legal description of the invention, leaving no room for interpretation about equivalents.

• Example 1: Mechanical Device

  Imagine a patent for a "self-adjusting wrench" that includes claims for:

  1. A handle with a fixed jaw.
  2. A movable jaw.
  3. A worm screw mechanism to adjust the movable jaw.
  4. A spring-loaded locking pin to secure the adjustment.

  A new wrench comes to market that features a handle with a fixed jaw, a movable jaw, a worm screw mechanism for adjustment, and a spring-loaded locking pin that secures the adjustment. Because this new wrench incorporates every single one of the elements precisely as described in the patent's claims, it would likely be found to literally infringe the patent.

• Example 2: Software Process

  Consider a patent for a "secure data transfer method" with claims specifying the following steps:

  1. Receiving a data packet from a source device.
  2. Encrypting the data packet using a specific cryptographic algorithm (e.g., AES-256).
  3. Adding a unique digital signature to the encrypted packet.
  4. Transmitting the signed, encrypted packet over a secure network protocol.
  5. Verifying the digital signature upon receipt by a destination device.

  If a competing software application is developed that performs data transfer by executing all five of these exact steps in the same sequence and manner described in the patent claims, it would constitute literal infringement. The application doesn't just achieve a similar result; it implements the patented method step-by-step as defined.