A usually tabular representation of a particular patent claim compared against an alleged infringing product or invalidating reference(s). The left-hand column usually has each claim limitation or element, the right hand column describes what feature of the accused product or reference meets or fails to meet that limitation and how. A carefully written claim chart will break out sub-elements that may require specific evidence that they are present. Sometimes an extra discussion column is added to the table, for example discussing law or claim construction issues from the prosecution history. Claim charts are also drafted in other formats.
Claim charts are typically required by courts as part of the written submissions in patents cases. They are also a normal part of any assertion of infringement and usually exchanged in patent licensing discussions. See Claim.