| 摘要 |
PURPOSE:To simply obtain an accurate electromagnetic lens by laminating an insulation sheet base where small piece conductor foils are printed at a prescribed density distribution via a foamed styrol. CONSTITUTION:Disk form conductor foils 12 having a diameter of 2mm are printed on a thin sheet insulation circular face board 10 to form dielectric boards 4A-4M. The distribution density of the foils 12 are changed at each concentrical zone to be high at the center of the dielectric board, and the width of the concentric zone is changed according to the diameter of each dielectric board. The dielectric boards 4A-4M are laminated with a foamed styrol in-between and formed as a sphere. Then the density of the foil 12 is high at the center of the sphere and the foil density and the specific dielectric constant are reduced isometrically toward the peripheral, then an electromagnetic lens 2 is formed. Thus, the simple lens is obtained with high accuracy in comparison with a conventional lens with concentrical spherical foamed styrol having different metallic grain density.
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