| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical system that has its characteristics changed little with respect to temperature changes, even when it uses a lens changing its optical characteristics by temperatures changes. SOLUTION: The state of this optical system changes from a state (a) to a state (b) when the temperature rises, as shown in Figure. The focal length of the collector lens 3 becomes large, and the focusing position moves from (a) to the right side as illustrated. At the same time, an expandable material 7 expands by heat, and a slider 8 moves to the right bringing an end 4 of the optical fiber to the focusing position moved to the right in the Figure. The thermal expansion coefficient and the length of the expandable material 7 are determined, in advance, so that the end of the optical fiber 4 always comes to the focusing position, even if the focal length 3 of the collector lens 3 changes by temperature changes and the focusing position changes, as a result. COPYRIGHT: (C)2006,JPO&NCIPI
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