| 摘要 |
PURPOSE:To reduce size, weight and cost by forming the secondary mirror in the form of a spherical mirror which is easily workable and inspectable, forming only the primary mirror in the form of an aspherical mirror, and using fiber reinforced plastics (CFRP) having a small coefft. of thermal expansion in forming at least one thereof. CONSTITUTION:The curved face of the primary mirror for converging a ray 6 incident parallel to an axis 3 always at the point D on the axis 3 is expressed by the equations 5, 6, where alpha, r1, r2 are expressed by the equations 1-4. Here a master mold 7 of a convex shape having the curved surface 9 of the primary mirror expressed by the equations 5, 6 is made by numerically controlled working of a metal. A fiber reinforced plastic CFRP8 is coated in laminar superposition as shown by (b) on the mold 7 and the plastic is separated from the mold 7, whereby the CFRP8 of a concave shape having the face 9 shown in (c) is obtd. Aluminum or the like is directly deposited by evaporation on such curved face, and the face is immediately usable as the curved face of the primary mirror. The reduction in the size, weight and cost of the reflecting optical system is thus made possible. |
