Patent ID: 7889434

Claim:
A zoom lens for endoscopic devices comprising: a lens mount; a plurality of lens units including a fixed first lens unit, a second lens unit and a fixed third lens unit arranged in the lens mount at an axial distance from each other, wherein the second lens unit is movable relative to the first lens unit and the third lens unit, a first fluid chamber formed in the lens mount between the first lens unit and the second lens unit; a first fluid conduit coupled to the first fluid chamber; a second fluid chamber formed in the lens mount between the second lens unit and the third lens unit; and a second fluid conduit coupled to the second fluid chamber, wherein a focal length of the zoom lens is hydraulically and/or pneumatically variable by varying an amount of fluid in one or more of the first fluid chamber or the second fluid chamber via one or more of the first fluid conduit or the second fluid conduit, and wherein the distance between the second lens unit and the first lens unit and the distance between the second lens unit and the third lens unit are hydraulically variable and/or the focal length of the lens units is pneumatically variable wherein a spring element is arranged in each of the first fluid chamber and the second fluid chamber between the plurality of lens units.