The function of lens in optics system is: focusing, collimating, imaging. The lenses usually require an anti-reflection coating to reduce the reflection of the lens surface, which reduces the loss of light energy and makes the imaging clearer.

A lens is an optical component made of a transparent substance (such as glass, crystal, etc.) that affects the wavefront curvature of light. It is a device that can polymerize or disperse light, and it has a real image and a virtual image. Widely used in security, car wear, digital cameras, lasers, optical instruments and other fields.

Various ordinary colorless optical lenses materials including fused silica, calcium fluoride, magnesium fluoride, silicon, germanium, zinc selenide, etc.; and plano-convex lenses of various wavelength, Double convex lens, plano-concave lens, double concave lens, super Hemispherical lenses, microsphere lens, meniscus lenses, cylindrical mirrors, rod mirrors, glued mirrors, etc.

The imaging rule of lens and convex lens

1. The lens is represented by a lens symbol (two V-shaped marks at two ends of a line segment), to draw the main optical axis, and to mark the optical center and focus.

According to the intersection of two refracted rays of the three special rays of the lens (generally the light of the optical center and the light parallel to the main optical axis), the characteristics of the image formed by the lens (such as real and virtual images, sizes, upside down, etc.).

1. When the lens image is formed, all the light from the point on the object that is incident on the lens is imaged at the same position, blocking a part does not affect the imaging of other rays directed at the lens, so the complete image can still be seen, but because the light that hits the image is reduced, so the brightness of the image on the screen is dimmed.

2. Convex lens imaging rule

(1) One condition for the convex lens to form real image is that the object distance is far than the focal length.

(2) Conjugated imaging means that the object distance and the image distance can be interchanged. In both cases, the inverted real image is enlarged and reduced.

4. Looking at the timepiece outside the double focal length through the convex lens, the image of the second hand is still rotating clockwise. Because the inverted real image is still in the normal direction when checking upside down, so it is still clockwise.