Patent ID: 8167794
Filing Date: 2012-05-01
Classification: A61B

Abstract:
1. An endoscope for detecting fluorescence emitted by a plurality of fluorescent labeling materials introduced into living tissue, comprising: an illumination unit; and an observation unit; wherein the illumination unit generates near-infrared illumination light that includes a wavelength band for excitation of the fluorescent labeling materials; the observation unit includes an objective optical system, an excitation light blocking filter, a wavelength tunable filter, and a detector; the combination of the excitation light blocking filter and the wavelength tunable filter passes light in the visible region, and has a passband in the infrared region which allows the fluorescence emitted from the fluorescent labeling material that is under observation to pass through, wherein a peak transmittance wavelength for the passband varies in accordance with the tuning of the wavelength tunable filter; and the spectral transmittance of said combination satisfies the following conditions: where T3 is the average transmittance within the visible wavelength range of 400 nm≦λ≦650 nm, T4 is the transmittance for the wavelengths within a range 20 nm above and 20 nm below the wavelength range of the excitation light generated by the illumination unit, T5 is the transmittance at the peak transmittance wavelength for an infrared passband, d5 is the infrared passband's full width as measured at 50% of the peak transmittance, and λ is the wavelength of light incident onto the wavelength tunable filter.