| 摘要 |
PROBLEM TO BE SOLVED: To realize illumination with little irregularity in a view field by using a diffusion plate as a surface light source together with an optical element having a one-dimensional periodical structure in a transmissive illumination apparatus for a stereomicroscope for observation in a wide magnification range. SOLUTION: The transmissive illumination apparatus for a stereomicroscope includes, successively from the light source, at least a collector lens, a diffusing plate and a convex lens 4b, and has an optical element 7 having a one-dimensional periodical structure disposed near the lens 4b which is disposed nearest to the observation side 5. The angleαat which the optical element 7 having the one-dimensional periodical structure divides the incident beam is in the range satisfying 0.5D/L<tanα<0.9D/L, wherein D is the effective diameter of a two-dimensional light source and L is the distance from the optical element having the one-dimensional periodical structure to the secondary light source. COPYRIGHT: (C)2004,JPO
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