The main function of the optical system is to image the object. An illuminated object or a self-luminous object can be regarded as composed of countless object points, and each object point emits a spherical wave, like a concentric light beam centered on the object point.
The concept of perfect image and perfect point: If a spherical wave is still a spherical wave (concentric beam) after passing through the optical system, the midpoint of the beam is the perfect image point. The image formed by all points on the object after passing through the optical system is called a perfect image.
Virtual reality of objects and images:
Intersection point of incident light rays: real object point Intersection point of extended line of
incident light rays: virtual object point
Intersection point of outgoing light rays: real image point Intersection point of extended line of
outgoing light rays: virtual image point
Real image:
Real virtual image:
virtual real image:
Virtual image:
1. Spherical optical imaging system
Knowing the radius of curvature of the spherical surface, the refractive index n and n', and the object space coordinates of light rays and L and U, find the L' and U' of the image side.
The derivation is as follows:
It can be seen that when L is constant, L' is a function of U. Therefore, light rays with different aperture angles emitted by the same object point have different L' values after refraction. This shows that the light wave surface is no longer a light wave surface after passing through the spherical optical system, so the imaging is not perfect. This phenomenon is called "spherical aberration" and is an inherent defect of spherical optical systems.
As shown below:
2. Paraxial spherical optical system
1. Optical path calculation
When the aperture angle is very small, I, I', and U' are very small, then the light in a very small area near the optical axis becomes the paraxial region, and the light in the paraxial region becomes the paraxial ray.
Then replace the sine of the angle with the corresponding radian value, we have
2. Properties of paraxial spherical optical system
2.1, Refractive Surface Imaging
1，垂直轴放大率：
2, 轴向放大率：
3, 角放大率：
4, 以上三者关系：
5，拉赫不变量：
2,2, coaxial spherical (multiple spherical) system
过渡公式：
