Patent ID: 6947091

Claim:
A focussing and focal length adjusting device for an optical lens system in an endoscopic video camera, comprising: a drive device for a focussing lens of the lens system, the drive device comprising a focussing sleeve encompassing the focussing lens, the focussing lens having an optical axis; two parallel strip-like piezoelectric bending actuators arranged to lie opposite one another on both sides of the focussing sleeve symmetrically to and along the optical axis, a free end of each said actuator being connected to the focussing sleeve by a respective joint member; an automatic focussing circuit for producing a focus adjusting signal which can be supplied to the piezoelectric actuators, the focussing circuit comprising a picture focussing acquisition device operative to acquire a degree of an in-focus position of the focussing lens, and a comparative device operative to compare the acquired degree of focussing with an earlier degree of focussing, the comparison producing an input signal for a voltage generator; an electromotoric zoom drive connected to a zoom objective of the optical lens system; and a zoom control circuit which with a manually inputted zoom signal produces a focal length adjusting signal for the zoom drive, wherein from a vertical synchronous impulse (V Sync ), obtained as a direct signal from camera electronics or extracted from a video signal by way of an extraction circuit, a time window is produced which is supplied to the focussing circuit and the zoom control circuit, the focussing circuit sending the focus adjusting signal to the piezoelectric actuator of the drive device and the zoom control circuit, and the focal length adjusting signal to the zoom drive only within a vertical blanking interval provided by the time window, wherein the voltage generator produces a focusing voltage corresponding to a focusing lens position and synchronously applies the voltage to both bending actuators.