CPC A61B 1/00186 (2013.01) [A61B 1/00096 (2013.01); A61B 1/05 (2013.01); G02B 5/28 (2013.01); G02B 23/243 (2013.01); G02B 23/2484 (2013.01)] | 20 Claims |
1. An optical filter system for inclusion into a distal end section of a video endoscope with an electronic sensor arranged in an image plane in the distal end section for receiving image light, the optical filter system comprises:
an objective lens system including at least a first lens, a second lens, and a third lens that are arranged in order from an object side to receive the image light and to pass the image light to the image sensor;
an optical filter optically located between the first lens and the second lens of the objective lens system, the optical filter being planar on both sides, wherein one side is an object side and the other side is an image side, the optical filter including a coating having a variable transmission that varies along a radius originating_from a center of a_central region of the optical filter to and extending to a peripheral region of the optical filter to transmit a predetermined wavelength of light from the central region to the peripheral region and block excitation light while allowing fluorescence light to pass.
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