Patent ID: 6716162
Filing Date: 2004-04-06
Classification: A61B

Abstract:
A fluorescent endoscope apparatus comprising a stimulating light projecting means for irradiating a living-tissue subject with stimulating light, and a photographing means formed of an optical element for transferring the autofluorescent light emitted from the live-subject tissue upon irradiation thereof by stimulating light and a photographing element for photographing the autofluorescent light transferred thereto by said optical element, wherein:said optical element is constructed so that the relationship of the normal-tissue fluorescent light of a strength K, which is the strength of the autofluorescent light emitted from the normal tissue of the live-tissue subject that has been transferred through said optical element and received by the photographing element, to the optical-element fluorescent light of a strength B, which is the strength of the fluorescent light emitted by said optical element when the reflected stimulating light reflected from the living tissue subject upon irradiation thereof by stimulating light is propagated through said optical element, satisfies the condition expressed by the formula: K&gE;BÃ—104; said photographing element is provided with a stimulating light cutoff filter for selectively cutting off said stimulating light; said stimulating light cutoff filter is provided with a panel of optical glass and a multiple layer dielectric film formed thereon; said optical element comprises a plurality of optical element components; and wherein said multiple-layer dielectric film and at least one of said optical element components through which the autofluorescent light is passed and which is disposed between said multiple-layer dielectric film and the living-tissue subject has properties satisfying the condition expressed by the following formulae: &lgr;ex>&lgr;80+(8/15)Ã—(&lgr;80âˆ’&lgr;05) Where: &lgr;ex=the wavelength of the stimulating light &lgr;80=the wavelength at which the optical element exhibits the transmittance of 80% &lgr;05=the wavelength at which the optical element exhibits the transmittance of 5%.