lens - a transparent glass body that is limited to spherical or cylindrical surface.There are such kinds of it: convex and concave.
structure of glass bodies
concave (diverging lens) and convex (collective) are composed of a wide and thin parts.The scattering is the wide part of the edges and thin in the center and a collective lens - on the contrary.
We place such glass body on Wednesday, where the refractive index higher than the refractive index of the above-mentioned lenses.Then diffuser get collective properties - and vice versa.
center of the sphere, part of which is the surface of the body, called the center of curvature.If one surface of the flat, then say he is at infinity.
straight line connecting the centers of curvature of the surfaces, which have a spherical shape, is defined as the main optical axis.It is perpendicular to the surface of the lens at the points through which it passes.The point lying on the optical axis in the center, an optical center.Any line that can pass through such a center at right angles to the main axis, is considered to be incidental.
point, where all the rays which, in turn, are parallel to the optical axis after emerging from the lens is called a focus.A point where the extension going rays that are scattered called imaginary focus diverging lens.
distance from the center (meaning the optical center) to the focus of the glass body is the focal length.The plane that is drawn through the point of focus and, in turn, extends perpendicular to the optical axis, called focal.
In order to make the imaging lens in the scattering of an object, which enables the lens, it is necessary to build the image of its extreme points.It should be remembered that the rays that fall on the glass body to be parallel to the main optical axis, when they come and go through the focus.A rays that fall on the lens through the focus, after the beam will be used in parallel.If the ray misses the optical center, after withdrawing from it will move in the same direction, that is, will not be refracted.
If we denote the distance from the object to the lens by b, and the distance from the lens to the image - in v, with the focal length of the mark V, then the following equation is true:
1 / b + 1 / v = 1 / V.
Such an equation is considered to be the formula of the lens.It is necessary to determine the distance to the image at a different location with respect to the subject of the glass body.
If this distance will eventually come out negative, it indicates that the image of the object is on the same side of the lens as the object.Therefore, if it is diverging lens, the focal length in the last formula should be taken with a minus sign, as the negative value can not be avoided.
quantities which focal length, according to the optical power.It is measured in diopters.Knowing the dimensions of the image, which gives the lens, and the object size can be determined linear magnification which gives the glass body.This increase is the ratio of image height to the height of the object itself.
diffuser.Imaging
subject is at infinity.Then the image of the subject will be in focus of the imaginary.Its dimensions and parameters can only assume, since the exact value can not be achieved.
subject is a short distance from the glass body.For a diverging lens, which would not have been the subject of his image will always be on the same side of the lens, where it is the object itself.The image will be reduced, and the imaginary straight.
