| 摘要 |
PROBLEM TO BE SOLVED: To provide a window panel made of a resin which can be manufactured with a small amount of a material, is inexpensive and lightweight, and can obtain a distorsionless visual field. SOLUTION: This window panel 10 made of the resin is thickest at a central section 10c and is made continuously thinner toward a peripheral edge section 10a from the central section 10c. The broken lines shown in Fig. 1 (a) are contour lines connecting the portions equal in thickness respectively, and the thickness is made continuously thinner at a fixed ratio toward the peripheral edge section 10a from the central section 10c in all directions. The surface 10d and the back face 10e of the window panel 10 made of the resin are formed into smooth curved faces curved in the same direction.
|
