Endoscope system for fluorescent observation

Abstract

An endoscope system is disclosed for detecting fluorescent light emitted in the near-infrared region by a plurality of fluorescent labeling materials introduced into a living tissue. An illumination system generates illumination light in the wavelength range 600 nm-2000 nm which serves as excitation light for the plurality of fluorescent labeling materials, and a detection system that can separately detect different ones of the plurality of fluorescent light emissions that are emitted at different wavelengths from among the plurality of fluorescent labeling materials is provided. The endoscope system may include a conventional-type endoscope having an insertion section, or a capsule endoscope that wirelessly transmits image data. By superimposing the image data obtained using reflected light in the visible region and fluorescent light emitted by the fluorescent labeling materials, improved diagnostic capabilities are provided.

1 - 30 . (canceled) 
     
     
         31 . An endoscope system for detecting fluorescences emitted by a plurality of fluorescent labeling materials introduced into living tissue, comprising:
 an illumination system; and   an observation system;   
       wherein
 the illumination system generates an excitation light for the fluorescent labeling materials; 
 the observation system includes an objective optical system, an excitation light cut-off filter, a wavelength tunable filter and a detector; 
 the wavelength tunable filter is formed as an etalon that includes a plurality of transparent substrates arranged so as to form a gap between said transparent substrates, the surfaces of the substrates that face each other across the gap have semi-transparent films, at least two of which have a spectral transmittance and the following conditions are satisfied:
   T1≧80% and
 
   T2≦35%,
 
 
 
       where
 T1 is the average transmittance in the wavelength region of 400 nm≦λ≦650 nm, and 
 T2 is a transmittance in the wavelength band having a lower boundary that is 50 nm shorter than the peak transmittance wavelength of the shortest fluorescence wavelength, and an upper boundary that is 50 nm longer than the peak transmittance wavelength of the longest fluorescence wavelength. 
 
     
     
         32 - 33 . (canceled) 
     
     
         34 . The endoscope system according to  claim 31 , wherein the etalon includes at least three semi-transparent base substrates. 
     
     
         35 - 43 . (canceled)