| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a spectroscopic instrument in which a change in dispersion characteristics is sufficiently small even when a temperature change is generated. <P>SOLUTION: The spectroscopic instrument includes a first group dispersion element and a second group dispersion element which are arranged in the incident order of a forward beam. When it is defined that an emission angle of the forward beam from the first group dispersion element at a first temperature T<SB POS="POST">1</SB>is θ<SB POS="POST">4</SB>, an emission angle of the forward beam from the first group dispersion element at a second temperature T<SB POS="POST">2</SB>different from the first temperature T<SB POS="POST">1</SB>is θ'<SB POS="POST">4</SB>, a difference θ'<SB POS="POST">4</SB>-θ<SB POS="POST">4</SB>of the emission angles is Δθ<SB POS="POST">4</SB>, an emission angle of a beam along an optical path through which the forward beam at the first temperature T<SB POS="POST">1</SB>is emitted from the second group dispersion element, which is also a reverse beam at the second temperature T<SB POS="POST">2</SB>, is θ"<SB POS="POST">5</SB>, an incident angle of the forward beam at the first temperature T<SB POS="POST">1</SB>on the second group dispersion element is θ<SB POS="POST">5</SB>, and the difference θ"<SB POS="POST">5</SB>-θ<SB POS="POST">5</SB>of the emission angle and the incident angle is Δθ<SB POS="POST">5</SB>, the Δθ<SB POS="POST">4</SB>is approximately equal to the Δθ<SB POS="POST">5</SB>. <P>COPYRIGHT: (C)2012,JPO&INPIT |
