| 摘要 |
PURPOSE:To keep a stable position of a mirror by absorbing expansion and contraction of the distance due to a difference of linear expansion coefficients between the mirror and a fixing table by attaching the mirror by combination of a hard ball and a spring force. CONSTITUTION:A mirror 6 is put on tables 2 with its reflective surface 7 contacting to spacers 5 through which the mirror contacts with hard balls 4. From the other side, springs 9 push plungers 8 against it. The balls and the plungers are present on one straight line and only compression acts on the mirror..Next, screws A of the table 2 are fastened by a regular torque and screws B are slightly loosened to move the ends 10 of the tables. The center P of the ball 4 moves to a point P' with a point A as the center. When a moving angle is theta, an angle made between a line AP and the perpendicular from the point A to the mirror 6 is alpha, a length of the line AB is l1, a quantity of movement of the mirror x1=l1{cosalpha-cos(alpha+theta)}. For moving the mirror by x1 when the length of the line AB is l2, the mirror is moved l2/l1 times at the point B. The screw B of a position adjusting plate is fastened. By this constitution, the stable position can be maintained even if the ambient temperature changes and the modulation of a crossing angle of two mirrors can be done easily. |
