US Patent 10279962 Tamper-evident thermoformed packaging

A package having a lid seated on a base where the edge of the seated lid is generally inaccessible, and where the edge is made accessible by a movement of a tamper-evident tab. The base and lid are configured so that opening of the tamper-evident tab locks the tab in the opened position. The inner edge of the tamper-evident tab is joined to the base by a hinge. The tamper-evident tab includes a protrusion that extends inwardly beyond the hinge. The lid includes a retention feature overlying the tamper-evident tab. The protrusion interacts with the retention feature to provide an audible indication when the tamper-evident tab is opened and to retain the tamper-evident tab in the opened position. The protrusion may be configured to lift the lid when the tamper-evident tab is in the opened position.