US Patent 7174558 Memory device

A memory device for recording, playback, and erasure of data through the application of an optical head along a memory medium includes a head carriage and a carriage lock. The head carriage moves the optical head along the surface of the memory medium, and the carriage lock prevents movement of the head carriage in response to a specific shock force. The carriage lock utilizes mechanical energy received from the shock force itself to prevent the movement of the head carriage.