| 摘要 |
PROBLEM TO BE SOLVED: To inexpensively obtain an lighting optical system which has a better light distribution characteristic and is simple in structure. SOLUTION: In a lighting optical system, a disc-shaped opal glass 131 is arranged so as to closely contact a tip end face of an optical fiber bundle 14 while the surface thereof is flush with the tip end face 33 of a scope. A light beam emitted from the optical fiber bundle 14 is transmitted through a transparent glass layer of the opal glass 131 and enters an opal layer. The light beam incident into the opal layer is diffused by component microscopic particles to allow irradiation of illumination light with a better light distribution characteristic outside expanding to a wider angle side. Thus, the observation peripheral part of an endoscope also can be lighted with a sufficient brightness.
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