US 12,379,580 B2
Lens having a fixed focal length and constant overall length for auto focus applications including five lens groups of ++--+, -++-+, -+++-, -++--, +-+--, +-++- or ++++- refractive powers
Dietmar Stuible, Wetzlar (DE); Sigrun Kammans, Herborn (DE); and Stefan Roth, Lahnau (DE)
Assigned to Leica Camera AG, Wetzlar (DE)
Filed by Leica Camera AG, Wetzlar (DE)
Filed on Nov. 19, 2021, as Appl. No. 17/530,636.
Application 17/530,636 is a continuation of application No. 16/333,938, granted, now 11,209,621, previously published as PCT/DE2017/100798, filed on Sep. 18, 2017.
Claims priority of application No. 10 2016 117 547.1 (DE), filed on Sep. 18, 2016.
Prior Publication US 2022/0075142 A1, Mar. 10, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. G02B 15/24 (2006.01)
CPC G02B 15/24 (2013.01) 9 Claims
OG exemplary drawing
 
1. A lens system with a fixed focal length, comprising: five lens groups, wherein three lens groups are mounted in a stationary manner and two lens groups are mounted in a displaceable manner along an optical axis, wherein the lens system comprises the following lens groups in order from an object side of the lens system to an image side:
a first lens group, as viewed from an object side, that is arranged in a stationary manner having a positive refractive power,
a second lens group configured as a focusing front group that is arranged in a displaceable manner,
a third lens group having a negative refractive power and containing a stationary iris diaphragm, an aperture of which is adjustable, the third lens group being arranged in a stationary manner,
a fourth lens group configured as a focusing back group that is arranged in a displaceable manner, and
a fifth lens group having a positive refractive power that is arranged in a stationary manner relative to an imaging plane in a lens barrel and both the focusing front group and the focusing back group are movable jointly relative to one another and to the lens groups arranged in a stationary manner in order to focus the fixed focus length lens system on objects at different object distances.