Optical Imaging System

Based on studying various propagation phenomena of light, various optical instruments have been designed and manufactured, such as microscopes for observing small objects, telescopes for observing distant objects, cameras, video cameras and so on.

There is usually an optical system in optical instruments, and its function is to image the observed object for observation by the human eye, or to detect it with photoelectric devices in the optics of prism.

Optical systems usually consist of one or more optical elements. Each optical element is composed of a medium with a certain refractive index surrounded by a spherical, plane or aspherical surface.

An optical system in which the center of surface curvature of each optical element constituting the optical system is on the same straight line is called a coaxial optical system, and the straight line is called the optical axis.

There are also non-coaxial optical systems (e.g., spectrometer systems that include dispersive prisms or dispersive gratings).

All optical elements in an optical system are composed of spherical surfaces and are called spherical systems.

If an optical system contains an aspheric surface, it is called an aspheric system.

A single lens is the basic unit of a coaxial spherical system.

Lenses can be divided into two categories according to different shapes: the first category is called a converging lens or a positive lens, which is characterized by a thick middle and a thin edge; the second category is a diverging lens or a negative lens, which is characterized by thin middle and thick sides.

According to the propagation law of light and wavefront, the propagation of light beam through the lens is studied.