Patent ID: 7319896
Filing Date: 2008-01-15
Classification: A61B,G02B

Abstract:
1. A capsule endoscope comprising: a light source; an objective optical system that forms an image of an object that is illuminated by the light source; an image pickup device that receives the image formed by the objective optical system; and a transparent cover that is positioned in front of the objective optical system; wherein the following conditions are satisfied: where θ/2 is the half-field angle, as measured from the optical axis of the objective optical system, that corresponds to the maximum image height of an object; a b f is the focal length of the objective optical system; X ΔI is the average value of the curvature of field of the tangential image surface T and the sagittal image surface S of the objective optical system at the half-field angle θ/2, where θ/2 is measured from the optical axis and the curvature of field is measured from the paraxial image plane.