English
Español1. Non imaging optics and related concepts
1.1 Non imaging optics
Unlike traditional imaging optics in the past, non imaging optics focus not on the ability of the light source to image on the target plane and the quality after imaging, but mainly on the energy utilization rate of the light source and the specific distribution of this energy in azimuth and space. As shown in Figure 1, in imaging optical systems, the main transmission is the light intensity and position information of the object points, while in non imaging optical systems, the main transmission, recombination, and distribution of the object point energy are carried out.
Figure 1 Functional schematic diagram of imaging optics and non imaging optics
1.2 Energy collection rate
Non imaging optics mainly focuses on energy distribution. If a non imaging optical device model is established as shown in Figure 2, it can be clearly seen that the plane represented by A is the incident aperture area, while the plane where A is located is the exit aperture area. Below, we assume that the output aperture area A of the device can allow all light to pass through this area and emit. The ratio c between the incident beam area and the output beam area is the energy collection rate. In general, the maximum energy collection rate in a 2D system is C2D=l/sin, while in a rotationally symmetric 3D system, the maximum collection rate is C3D=1/sin2 θ。 The concept of energy collection rate is mainly applied in the evaluation of non imaging optical systems.
Figure 2 Concept of Energy Collection Rate
1.3 Geometrical optics
At present, Geometrical optics has been widely used in the design of optical systems. The design of imaging optics and non imaging optics must be based on the theory of Geometrical optics. There are four basic laws in Geometrical optics, namely, the straight line propagation law of light, the independent propagation law, the refraction law and the reflection law.
(1) The law of linear propagation of light. This law mainly explains the problem that in a uniform and isotropic medium, light propagates along a straight line.
(2) The law of independent propagation of light. When beams of light emitted by different light sources pass through a point located in space in various directions, they are independent of each other and do not affect each other.
(3) The law of reflection of light. When the three types of rays, namely incident, reflected, and projected, are located in the same plane, the absolute value of the reflection angle is equal to the incident angle and the sign is opposite, while the incident and reflected rays will be located on both sides of the normal of the projection point.
(4) The law of refraction of light. Similar to the law of reflection, when three types of light rays are located in the same plane, the ratio of the sine of the incident angle to the refractive angle is not related to the size of the angle, but mainly depends on the specific properties of the medium.
