Mitsubishi Denki Kabushiki Kaisha

Kouki Asari

Izumi Mikami

Aki Sasaki

Kenichi Nishiguchi

Eiichi Sakai

Hiromichi Mori

The control of a mirror's shape, such as for use in large reflecting telescopes, is associated with discrete points so as to avoid incurring constraints and exerting undesirable stress on the reflecting mirror through control unrelated to the mechanical characteristics. Thus, a reflecting mirror is approximated by a non-constrained circular plate having a similar mechanical structure, and an eigenfunction value arithmetic unit calculates values of Bessel-Fourier functions which are eigenfunctions of free vibrations of the circular plate. Using these function values, a mode displacement identification unit approximates a required mirror displacement, which is necessary to correct for wavefront distortion, with a linear combination up to a prescribed mode of vibration of the eigenfunction. A support mechanism command unit controls an actuator so that the value of the linear combination function equals the amount of mirror displacement at a position supported by a reflecting mirror support mechanism.

Shape control apparatus for reflecting mirrors

A reflecting mirror, wherein mirror segments are fused together thereby composing the reflecting mirror by formulating square sums of displacements at a plurality of sampling points on a mirror surface of the reflecting mirror as a function of a thermal expansion coefficient vector having components of deviations of thermal expansion coefficients of the respective mirror segments from the average thermal expansion coefficients of all the mirror segments, positions of the components corresponding to arranging positions of the respective mirror segments; generating a stochastic process wherein the smaller the square sum of the displacement of the thermal expansion coefficient vector, the larger the probability whereby the thermal expansion coefficient vector appears, by a computer using random numbers; selecting the thermal expansion coefficient vector minimizing the square sum of the displacement from the appeared thermal expansion coefficient vectors; and arranging and fusing together the mirror segments in accordance with the components thereof.

Fused segment reflecting mirror

A method of fabricating a reflecting mirror, wherein mirror segments are fused together thereby composing the reflecting mirror comprising, formulating square sums of displacements at a plurality of sampling points on a mirror surface of the reflecting mirror as a function of a thermal expansion coefficient-vector having components of deviations of thermal expansion coefficients of the respective mirror segments from the average thermal expansion coefficients of all the mirror segments, positions of the components corresponding to arranging positions of the respective mirror segments; generating a stochastic process wherein the smaller the square sum of the displacement of the thermal expansion coefficient vector, the larger the probability whereby the thermal expansion coefficient vector appears, by a computer using random numbers; selecting the thermal expansion coefficient vector minimizing the square sum of the displacement from the appeared thermal expansion coefficient vectors; and arranging and fusing together the mirror segments in accordance with the components thereof.

Method of fabricating a reflecting mirror

The present invention relates to a method of fabricating a reflection mirror formed by sticking together a plurality of mirror segments for use on a reflecting telescope or the like. The mirror segments are arranged so that the thermal deformation of the reflecting mirror is limited to the least possible extent. The method comprises steps of: setting a plurality of sample points on the mirror surface; developing a matrix connecting a coefficient of the thermal expansion (CTE) vector having the deviations of the respective CTEs of the mirror segments from the average CTEs obtained by averaging the CTEs of the mirror segments as components corresponding to the respective positions of the mirror segments with the displacements of the sample points; selecting a vector making the sum of squares of the displacements a minimum among those obtained by rearranging the components of the CTE vector; and arranging the mirror segments according to the positions of the components of the selected vector.

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Amagasaki, Japan

Kouki Asari