US Patent 7400342 Optical observation apparatus with video device

An optical observation apparatus includes: an optical system which produces an image of an object being observed and a video device (7) for recording the image and producing an image signal. The video device (7) includes a first memory (71) for temporarily storing the image signal, a second memory (73) in data communication (77) with the first memory (71), and a control device (75) in communication (76A, 76B) with both memories (71, 73) for controlling the storage procedure in the first memory and data transfer from the first to the second memory. The control device (75) controls the storage procedure and the data transfer so that overwriting of such data already stored for a given period of time in the first memory (71) is effected and that transfer of the content of the first memory (71) to the second memory (73) takes place as a reaction to a trigger signal.