US 9,808,141 B2
Endoscope
Nobuhiko Sone, Tokyo (JP); and Hideyasu Takato, Tokyo (JP)
Assigned to OLYMPUS CORPORATION, Tokyo (JP)
Filed by OLYMPUS CORPORATION, Tokyo (JP)
Filed on May 28, 2015, as Appl. No. 14/724,177.
Application 14/724,177 is a continuation of application No. PCT/JP2014/063513, filed on May 21, 2014.
Claims priority of application No. 2013-108141 (JP), filed on May 22, 2013.
Prior Publication US 2015/0257630 A1, Sep. 17, 2015
Int. Cl. G02B 23/24 (2006.01); G02B 23/26 (2006.01); A61B 1/06 (2006.01); A61B 1/00 (2006.01); A61B 1/05 (2006.01)
CPC A61B 1/00096 (2013.01) [A61B 1/00 (2013.01); A61B 1/05 (2013.01); A61B 1/0676 (2013.01); G02B 23/243 (2013.01); G02B 23/2423 (2013.01); G02B 23/26 (2013.01)] 9 Claims
OG exemplary drawing
 
1. An endoscope comprising:
an observation optical system provided in a distal end of an insertion portion, the observation optical system including a plurality of lenses and having a function that allows a magnified observation close to a subject; and
a plurality of illumination optical systems provided in the distal end of the insertion portion, the plurality of illumination optical systems each including a plurality of lenses and illuminating the subject with illuminating light,
wherein the plurality of illumination optical systems include a first illumination optical system and a second illumination optical system different from the first illumination optical system,
each of the first and second illumination optical systems satisfies the following conditional expression (3),
in a close observation in which a distance between a distal end face of the insertion portion and the subject is an arbitrary distance of from 1.5 mm to 2.5 mm, where ITM is a maximum brightness within an observation view field angle and ITC is a center brightness, and
in a normal observation in which the distance between the distal end face of the insertion portion and the subject is 50 mm, where IWC is a center brightness and IWS is a brightness at a position of 80% of a maximum view angle, the following conditional expressions are satisfied:
0.3<ITC/ITM<0.45  (1);
0.15<IWS/IWC<0.25  (2); and
0.3<fLfTLIH<0.6  (3),
where fL is a focal length of each of the entire illumination optical systems, fT is a focal length of the entire observation optical system in a maximum magnification, φL is an outer diameter of a lens that is farthest on an object side of each illumination optical system, and IH is a maximum image height of the observation optical system.