《应用光学.-.常见的像差》由会员分享，可在线阅读，更多相关《应用光学.-.常见的像差（76页珍藏版）》请在金锄头文库上搜索。
1、6.8 The Illuminance Equation For Image Points Off The Axis: is the image field angle of view E is the marginal illuminance(边缘光照度)E0 the axial illuminance(轴上光照度)K is the radio of clear aperture (通光孔径)betweenthe oblique(倾斜的) beam and the axial beamChapter 7 Image Quality Of Optical System常见的像差7.1 Intr
2、oduction( 简介) n1) Two requirements for the imaging properties (成像性能)of the system:nThe first requirement includes the effective focal length(有效焦距)，the object and image distance(物距和像距), the magnification(放大率), the entrance pupil (入瞳)position and distance, etc.nThe second requirement includes the imag
3、e quality of the optical system. nThe image formed by the system should be similar to the object, and should be clear (清晰) enough and distort (变形) as small as possible.2) Two type of the aberrations(像差):nThe first type of aberrations are suitable for the measurement of an optical instrument which is
4、 already produced(制造完成后).nThe second type of aberrations are suitable for the design stage(设计阶段).Resolution Measurement1 nThe so-called resolution power of an optical system is the smallest distance which can be resolved by the systemn系统所能分辨的最小的间隔所能分辩的最小间隔，可以代表系统成像的清晰度空间频率Fig. 7.1 Resolution test pl
5、ate nIn the actual measurement, a resolution test plate(分辨率板) is used to be the object. Then the smallest distance(mm)on the image plane which can be resolved by the system will be the resolution power (分辨能力) of the system. nSometimes the reciprocal(倒数)is also used to represent the resolution power:
6、nThe spatial frequency(空间频率): =1/ (7.1)，the unit of is lp/mm. modulation transfer function (MTF) Star Test1 nIf the image is not ideal or is a blur(one object point can not be imaged as a perfect image point according to wave optics), the size and the energy distribution (分布) of the blur (光斑) can be
7、 used to estimate the image quality of the system. n根据弥散斑的大小和能量分布的情况，就 可以评价系统像质的优劣。Geometrical optics2 nGeometrical aberration (几何像差)， Wave front aberration(波像差)，Spot diagram(点列图)，Geometry OTF（ Optics Transfer Function）(几何光学传 递函数), etc. 单色光像差有五种： 球差Spherical aberration 彗差Coma,comatic aberration 像散As
8、tigmatism 场曲Curvature of field 畸变Distortion复色光像差有两种： 轴向色差The axial chromatic aberrations 垂轴色差The lateral chromatic aberrations几何像差几何像差: :Physics optics2nPoint Spread Function(点扩散函数,点列 图)，Relative central luminous intensity(相对中心光强)，Physical OTF(Optics Transfer Function)(物理光学 传递函数), etc. 7.2 Color Dis
9、persion(色 散) And Chromatic Aberrations(色差)n1) The Define Of Color Dispersion(色散)nFor a certain medium the difference n( ) of two index of the indexes for two different wavelengths, is called the color dispersion(色散).nWe select the difference ( ) of two indexes of two special wavelengths, (C光) and (F
10、光), to represent the color dispersion, which is called mid-dispersion (中部色散).Chromatic Aberrations(色差)兰兰绿绿红红l lF F - -l lFCFC l lc c AFAF AcAc 轴向（位置）色差定轴向（位置）色差定 义为：义为：The Axial Chromatic Shifts (轴向色差) 较长较长 ;较较短 较较大; 较较小 nBecause of the fact that the index of refraction varies as a function of the w
11、avelength of light, the focal length also varies with wavelength.nThe image points of different wavelengths locate along the axis in turn, and the distance along the axis between the image points of different wavelengths represent the axial chromatic shifts(轴向色差). nUsually, the distance along the ax
12、is between two image points of wavelength F and wavelength C is called the axial chromatic aberration(轴 向色差).nWe use and to represent the paraxial image distances of wavelengths F and C, then the axial chromatic aberration can be defined as (7.2). 称为色差校正不 足称为色差校正过 渡若AF和AC重合，则称为光学系统对F光(兰)和C光(红)消色差。消色
13、差系统消色差系统是指对是指对两种两种色光色光消轴向（位置）消轴向（位置） 色差的系统。色差的系统。位置色差的性质类似于球差 。光学系统只能对一个孔径的光线进行校正 色差。一般情况下对一般情况下对0.70.7孔径孔径的光线校正位置色差的光线校正位置色差 。随着接收器的不同，应取接近接收器有 效波段边缘的波长进行校色差B BA Ay yz zF F y yz zc c 垂轴色差The lateral color aberrations (垂轴色差) 较高; 较低。nFrom the equation we can see that since the effective focal length
14、of the lens varies with the wavelength the image height y will also vary with the wavelength.nThe differences of the image heights of different wavelength lights are the so- called lateral color aberrations(垂轴色差 ).nUsually, the lateral color aberration is defined on the paraxial image surface of D l
15、ight, and it is just the distance vertical to the axis between two image points of wavelength C and F. We use and to represent the image heights of wavelengths F and C, then the lateral chromatic aberration can be defined as(7.3). 7.3 The Axial Monochromatic Aberration(轴上点的单色 像差) Spherical Aberratio
16、n( 球差)Fig.7.4nIn Fig.7.4 we can see that the rays emitted from one object point will not intersect at(相交于) one point after refraction, or the system forms a blur( 模糊的) image. Usually, we use spherical aberration to denote the spread of the rays intersection along the axisn(用球差表示光线与光轴的交点沿光轴方向 的离散程度). 2）球差的表达式：nThe axial spheri
