放大倍率与分辨率 ·放大倍率 一人眼从显微镜目镜中所见的被观察物尺寸与原 物尺寸的比值。 一人眼明视距离除以物镜焦距。 分辨率 一区分两个相邻点的能力 ·放大倍率上限？ 11
放大倍率与分辨率 • 放大倍率 – 人眼从显微镜目镜中所见的被观察物尺寸与原 物尺寸的比值。 – 人眼明视距离除以物镜焦距。 • 分辨率 – 区分两个相邻点的能力 • 放大倍率上限？ 11
人眼的分辨率 μ=133 Object μ1 Image 4=1.38 Iris is a variable μ=1.38-1.41 aperture that adjusts intensity of Optic nerve detects signal light allowed in. projected onto retina by curved lens. ~0.2 mm 25 cm distance 12
人眼的分辨率 12 ~0.2 mm @ 25 cm distance
Ro .612λ 二 M nsina R (a) (b) (c) 13
13 𝑅0 = 0.612𝜆 𝑛𝑠𝑖𝑛𝛼 𝑀
透镜的分辨率极限 Ro 0.612元 M nsina nsin:.数值孔径(numerical aperture,NA) Visible Light:~6000 A X-rays: λ0.5-2.5A Electrons: λ~0.05A 14
透镜的分辨率极限 14 ∆𝑟0= 𝑅0 𝑀 = 0.612𝜆 𝑛𝑠𝑖𝑛𝛼 nsin: 数值孔径(numerical aperture, NA)
有效放大倍率 Resolution of naked eye Effective magnification= Resolution of microscope Effective magnification (Mn: resolution of eye 0.2mm ≈1333× max.resolution of LOM 0.00015mm M's >Mr make the image bigger,but do not provide any additional details.This is termed "empty magnification. 15
有效放大倍率 15