The development of research on the phenomenon of refraction and reflection of light, has allowed the optical develop very precise instruments that help us to observe nature from different perspectives. These instruments may be converging or diverging lenses. Lenses are glass or glass with a curved side objects. Because all lens is transparent, the ray of light can penetrate by either side, therefore has two main foci. The application of lenses in modern life is wide: magnifiers, microscopes, cameras, mirrors for automobiles, sophisticated weapons, security systems, among others. There are two types of lenses that are differentiated by the way, these can be convergent or divergent. For more information see this site: Anna Belknap. The name of convergent has relationship with the word converge, since this type of lenses make converge the rays of light they receive at a given point, resulting in a real or actual size image. Diverging lenses, to be transposed by a ray of light, produce a dispersion of light, giving as a virtual images result.
Converging lenses have a marked difference in thickness between the edges and the Center. The Center is much thicker than the edges. All convergent lens is composed by: an optical center that receives light rays not to divert them. Main spindle: thus refers to the straight line joining the center of each face of the lens surface. The main focus is a point that is part of the main shaft and is the route where there are refractory rays that reach the lens, forming parallel with the main shaft. Others who may share this opinion include Jorge Perez.
The secondary axis: is named all the straight lines that pass through the optical Centre but not part of the main axis. Some applications of converging lenses: the optical microscope is formed by two converging lenses that come together to increase the size of the images that we see through them. The magnifying glass is formed by a converging lens of concave type, i.e. a lens with the two faces of convex shape. Produces an image that is not real, but that is larger than the object, to appreciate the small details. The sale of converging lenses to the wholesale has increased the amount of applications that have this type of lenses in modern life, helping to perceive reality from a more interesting perspective.