Lens system

Abstract

A lens system comprises a first lens group and a second lens group, and is configured to form an image at a first magnification and at a second magnification. The lens system has a common optical axis in both magnifications. The lens system is further configured to form an intermediate image between the first lens group and the second lens group at the first magnification. The intermediate image formed in the first magnification is further imaged onto an optical detector. In the first magnification, the second lens group acts as a relay lens imaging the intermediate image onto the optical detector. In the second magnification, the first and second lens groups together form an image on the optical detector without forming an intermediate image.

1 . A lens system comprising:
 a first lens group and a second lens group configured to form an image at a first magnification and at a second magnification,   wherein the lens system has a common optical axis in both magnifications, and   wherein the lens system is further configured to form an intermediate image between the first lens group and the second lens group only at the first magnification and, at the first magnification, the second lens group acts as a relay lens and is configured for imaging the intermediate image onto an optical detector.   
     
     
         2 . The lens system of  claim 1 , wherein the first magnification is associated with a macroscopic view and the second magnification is associated with a microscopic view. 
     
     
         3 . The lens system of  claim 2 , wherein the absolute value of the first magnification is at least 100 times smaller than the absolute value of the second magnification. 
     
     
         4 . The lens system of  claim 2 , wherein the first lens group has a focal length F 1  and the second lens group has a focal length F 2  and the first lens group and the second lens group are at a distance of D 12 , and wherein the focal length F 1  of the first lens group is smaller than the distance D 12 . 
     
     
         5 . The lens system of  claim 4 , wherein the focal length F 1  of the first lens group and the focal length F 2  of the second lens group comply with |F 2 /F 1 |>1. 
     
     
         6 . An optical biopsy device comprising:
 an inserting tube to be inserted into a body; and   a lens system secured in a tip end of the inserting tube having a first lens group and a second lens group configured to form an image at a first magnification and at a second magnification, wherein the lens system has a common optical axis in both magnifications, and wherein the lens system is further configured to form an intermediate image between the first lens group and the second lens group only at the first magnification.   
     
     
         7 . The optical biopsy device of  claim 6 , further comprising a switchable lens system configured for switching between the first magnification and the second magnification. 
     
     
         8 . The optical biopsy device of  claim 7 , wherein the switchable lens system is configured to work according to an electro-wetting principle. 
     
     
         9 . The optical biopsy device of  claim 7 , wherein the switchable lens system is configured to work by displacing a lens. 
     
     
         10 . The optical biopsy device of  claim 6 , wherein the second lens group consists of at least one fixed lens and one switchable lens. 
     
     
         11 . The optical biopsy device of  claim 6 , further comprising an image sensor, wherein the image formed by the lens system is imaged on to the image sensor. 
     
     
         12 . The optical biopsy device of  claim 6 , further comprising:
 a fiber bundler configured for relaying the image formed by the lens system; and   a console optically coupled to the fiber bundler and configured for reading out the image formed.   
     
     
         13 . The optical biopsy device of  claim 6 , further comprising:
 a single scanning fiber configured for reading out the image formed by the lens system; and   a console optically coupled to the single scanning fiber and configured for reconstructing the image formed.