| 摘要 |
PROBLEM TO BE SOLVED: To provide a concave diffraction mirror which has excellent slit imaging performance for all wavelengths in the visible range and is suitably mass-produced, and a spectral device using the same. SOLUTION: Disclosed is the concave diffraction mirror having a reflecting surface which is concave and aspherical and has a diffraction grating formed on a surface, the concave diffraction mirror being characterized in that the diffraction grating is plane-symmetrical with respect to a reference surface passing the center point of the reflecting surface and being in a dispersion direction of the diffraction grating and has a shape linear in a direction orthogonal to the reference surface when projected in a tangent plane direction on a virtual tangent plane at the center point of a virtual reference spherical surface passing the center point, where the sectional shape of the reflecting surface in a reference surface direction is smaller in curvature than the reference spherical surface on one side with respect to the center point as the separation distance from the center point increases, and larger in curvature than the reference spherical surface on the other side as the separation distance from the center point increases. COPYRIGHT: (C)2009,JPO&INPIT
|
