US Patent 7093945 Imaging apparatus for endoscopes

An imaging apparatus for endoscopes has an objective optical system forming an image of an object and a holding frame retaining the objective optical system. The objective optical system is provided with optical filters which reduce a transmittance in a particular wavelength region of illumination light irradiating the object to 0.1% or less and has a light passage preventing device blocking light passing through a clearance between the outside surfaces of the optical filters and the inside surface of the holding frame retaining the optical filters.