材料微觀分析光學(xué)原理

1、電子顯微分析Electron MicroscopySun YaUniversityThe center for nanotech researchLight Microscopes v.sElectron Microscopes2Electron Micrscopy, SYSU, S RenSept.2012Optic microscopy3Electron Micrscopy, SYSU, S RenSept.2012像的元素色彩明暗對比（襯度）4Electron Micrscopy, SYSU, S RenSept.2012增強(qiáng)襯度的方法樣品表面腐蝕，增加不同組織之間反射方向的差別（晶界及

2、點(diǎn)陣缺陷選擇腐蝕、物相選擇腐蝕、點(diǎn)陣取向選擇腐蝕等）改變光路，選擇性成像。（明場、暗場像，偏振光成像，掠射光成像等）施加濾色片5Electron Micrscopy, SYSU, S RenSept.2012Bright field image6Electron Micrscopy, SYSU, S RenSept.2012Dark field image7Electron Micrscopy, SYSU, S RenSept.2012Tolanskyerference Contrast完整結(jié)構(gòu)導(dǎo)致的襯度8Electron Micrscopy, SYSU, S RenSept.2012Volu

3、me fractionArea fraction9Electron Micrscopy, SYSU, S RenSept.2012Line fraction10Electron Micrscopy, SYSU, S RenSept.2012Pofraction11Electron Micrscopy, SYSU, S RenSept.2012成像的三個特質(zhì) 像的分辨率 Higher resolution 景深（場深）Higherdepth of field HigherDepth of focus12Electron Micrscopy, SYSU, S RenSept.20121），分辨率1

4、3Electron Micrscopy, SYSU, S RenSept.20121）分辨率 Airys ringsDiffraction of a wave by any circularrture leadsto a set of cones, which appear as concentric rings when imaged.The centralense spot (the Airy Disc) contains84% of the totalensity.14Electron Micrscopy, SYSU, S RenSept.2012Critical distance rd

5、15Electron Micrscopy, SYSU, S RenSept.2012像分辨率Resolution of imagination 0.61N.A.r最小分辯距：d數(shù)字孔徑 N.A.=n Sin n= refractive index of the medium.=wavelength of the light.=half the acceptance angle of the lens.透鏡孔徑角 2Electron Micrscopy, SYSU, S RenSept.201216有效放大倍數(shù)人眼最小分辯距離 L0.2 mm有效放大倍數(shù)MeMe * rd L0.2 mmTypi

6、cally , rd =0.2 um,Me = 100017Electron Micrscopy, SYSU, S RenSept.2012Me 0.2 mm/ rdSizes of cells and their components drawn on alogarithmic scale, indicating the range ofreadily resolvable objectshe light andelectron microscope.18Electron Micrscopy, SYSU, S RenSept.20122），場深（景深） Depth of field Dobi

7、croscopy,therangeofdistanceatthespecimen parallel to the illuminating beam inwhich the object appears to be in focus.19Electron Micrscopy, SYSU, S RenSept.2012影響景深的 相機(jī)與物體的距離距離越大，景深越大 聚焦的距離聚焦距離越大，景深越大 光闌的大圈）圈數(shù)值越大），景深越大光闌越20Electron Micrscopy, SYSU, S RenSept.2012景深與分辨率的關(guān)系高分辨率 大視角，大光闌大景深 小視角，闌21Electr

8、on Micrscopy, SYSU, S RenSept.20123），Depth of focusicroscopy,therangeofdistanceat the image plane (i.e. the eyece,camera,orphotographicplate)inwhich a well focussed object appears to be in focus.22Electron Micrscopy, SYSU, S RenSept.2012Spherical aberration 球差Spherical aberration arises because a thin lens brings rays at its periphery to focus at a shorterfocal distan