Patent ID: 7642525

Claim:
A fluorescent observation apparatus, comprising: a light source; a beam splitting device selectively reflecting light from the light source; an objective for illuminating or observing a specimen; a stage for fixing the specimen; a wavelength selection device for selecting a desired wavelength range based on rays that pass through the beam splitting device; and a detector for detecting light that passes through the wavelength selection device, wherein the following conditions are satisfied: λ1−λ2≧180 nm, |Δ1−Δ2|<0.2 μm, wherein λ1 is the longest wavelength and λ2 is the shortest wavelength in illuminating the specimen using two or more wavelengths, and Δ1 and Δ2 are the focal point on the optical axis of the objective with respect to λ1 and λ2 respectively.