| 摘要 |
An endoscope illumination optical system includes a surface light source, a positive first lens element, a positive second lens element, in this order from the surface light source. The endoscope illumination optical system satisfies the following conditions: 0.40<f/D<0.53 (1) 0.40<0.5·D·θ<0.56 (2) wherein f: the combined focal length of the positive first lens element and the positive second lens element; D: the maximum diameter of the surface light source; R1: the radius of curvature of a first surface, of the positive first lens element, facing toward the surface light source; R2: the radius of curvature of a second surface, of the positive first lens element, facing toward a surface to be illuminated; n1: the refractive index of the positive first lens element; d1: the thickness of the positive first lens element; andθdesignates an angle defined as (1+0.85d1/R2)(1−1/n1)/R1−1.05/R2.
|
