视场光阑与孔径光阑定义.doc

Chapter V Field stop and aperture stop 视场光阑与孔径光阑 Field stop and aperture stop 视场光阑与孔径光阑 Filed of view 视场 Vignetting and field lens 渐晕与场镜 Telecentric system 远心系统 Depth of focus and depth of field 焦深与景深 Stray light in lenses 透镜中的杂散光 Aperture stop: The stop close to lens limits the size of the bundles of rays of axis point. It determines the amount of light reaching any given point in the image, therefore controls the brightness of image (image plane). Field stop: Just front of the focal plane limits the angle at which the incident bundles can get through to this plane (image plane). It determines the extent of the object or the field. (Field stop is usually made to coincide with image.) 二、Entrance pupil and exit pupil : The image of aperture stop formed by preceding it. : The image of aperture stop formed by following it. The image of this stop, as formed by the lens is found to lie at the position . *Since is inside the focal plane, its image lies in the object space and is virtual and erect, PL called entrance pupil. * lies in the image space, called exit pupil. `*,, are pairs of conjugated points. Any ray in the object space directed through one of these points will after refraction pass through its conjugate point in the image space. 三、Chief ray Any ray in the object space that passes through the center of entrance pupil is called chief ray. After refracting also pass through the center of the exit pupil.*Chief ray is a central ray of oblique rays. preliminary design of an optical instrument, must determine which one actually does the limiting? The entrance pupil of the centric system is the image of the aperture stop formed by all lenses preceding it. The exit pupil is the image formed by all lenses following it. 四、Stop between two lenses Chief ray pass through the entrance pupil, the stop and the exit pupil. How to determine aperture stop? 五、?Two lenses with no stop  The periphery of any lens in system is a potential stop. Object at infinity, : ent