第二章研究细胞的方法 第一节显微镜技术
第二章 研究细胞的方法 第一节 显微镜技术
显微镜与分辨率 1.明视距离 物体在人眼视网膜上成像的大小和 物体与眼睛的距离有关。物体离眼睛 的距离越近,枧网膜上的物像就越大 但眼睛的曲光度就随之增大,眼部肌 肉就越发疲劳。经测试在物体离人眼 25cm时,看物体又清楚,眼肌也不疲 劳,因此把人眼正常工作距离定为 25cm,称之为明视距离
一、显微镜与分辨率 1.明视距离： 物体在人眼视网膜上成像的大小和 物体与眼睛的距离有关。物体离眼睛 的距离越近，视网膜上的物像就越大， 但眼睛的曲光度就随之增大，眼部肌 肉就越发疲劳。经测试在物体离人眼 25cm时，看物体又清楚，眼肌也不疲 劳，因此把人眼正常工作距离定为 25cm，称之为明视距离
a1 Normal eye (6)Myopic (ye ()Hyperopic eye Defect of vision
2、分辨力和光镜的分辨极限 分辨力( Resolution):又叫分辨本 领,是指将邻近两点清晰区分辨认的 能力。 microscop cone of ill n and therefore on both he cond the objective lens. It is he formula s a co where 0= half the angular width of the cone of ondenser lens from a typical point in the specimen ses a con since the maximum width is 180 rays each point of the ns the refractive index of the medium specimen usually air or oil) separating the LIGHT specimen from the objective and ondenser lenses 2. the wavelength of light used (for white light, a figure of 0.53 um is commonly assumed) NUMERICAL APERTURE: n sin e in the aperture, the greater the resolution and the quation above is called the numerical aperture brighter the image (brightness is important in of the lens (NA) and is a function of its fluorescence microscopy ). However this advan collecting ability For dry lenses this cannot be tago is obtained at the exponse of vory shor more than 1, but for oil-immersion lenses it can working distances and a very small depth of field be as high as 1. 4. The higher the numerical
2、分辨力和光镜的分辨极限 分辨力（Resolution）：又叫分辨本 领，是指将邻近两点清晰区分辨认的 能力
分辨极限( Limit of resolution) 对可见光来说,能清楚分辨出相邻两点 之间的最小间隔为02um R=0.61/n.sin0 =0.61×0.5um/1.5×1 0.2um
分辨极限（Limit of resolution） 对可见光来说，能清楚分辨出相邻两点 之间的最小间隔为0.2m。 R ＝ 0.61 / n .sin ＝ 0.61×0.5 m / 1.5×1 ＝ 0.2 m