Optical Systems for Multi-Sensor Endoscopes

An objective lens system for at least one of a front-pointing and side-pointing camera sensors of a multi-sensor endoscope, the objective lens system comprising:

• a front and a rear sub-systems separated by a stop diaphragm, wherein
• said front sub-system comprises a first front negative lens and a second front positive lens, and
• said rear sub-system comprises a first rear positive lens, an achromatic sub-assembly (optionally, a compound achromatic sub-assembly) comprising a second rear positive lens and a third rear negative lens,
• wherein the following condition is satisfied:
• f(first rear positive lens)≦1.8f, where f is the composite focal length of the total lens system and f(first rear positive lens) is the focal length of said first rear positive lens.

A tip section of a multi-sensor endoscope comprising an optical system comprising:

• a front-pointing camera sensor;
• a front objective lens system;
• a side-pointing camera sensor;
• and
• a side objective lens system,
• wherein at least one of said front and side objective lens systems comprises a front and a rear sub-systems seperated by a stop diaphragm,
• said front sub-system comprises a first front negative lens and a second front positive lens,
• said rear sub-system comprises a first rear positive lens, an achromatic sub-assembly (optionally, a compound achromatic sub-assembly) comprising a second rear positive lens and a third rear negative lens, wherein the following conditions are satisfied:
• f(first rear positive lens)≦1.8f, where f is the composite focal length of the total lens system and f(first rear positive lens) is the focal length of said first rear positive lens.