Military Night Vision Goggles

Lens coating:

Different coatings can bring different gains, such as filtering out more interfering light, improving the user experience, protecting the lens, extending the service life, etc.

1. Coating can increase the transmittance of the glass and improve the brightness of observation; reduce the glare and ghosting of the lens and improve the contrast of observation.

2. Common anti-reflection film colors are red film, blue film and green film, and their transmittance is: red film < blue film < green film. Full surface multilayer coating (FMC) is the best coating.

3. When purchasing optical equipment, pay attention to the degree of reflection of the lens. The dimmer the reflection, the better the coating, and vice versa.

1. Why coating?

When light passes through the optical glass lens of the telescope, the light will not only refract, but also reflect. Reflection will cause light loss, resulting in darker imaging. If there are multiple lenses, more light will be reflected, and this light loss is quite large. If the internal extinction is not good, part of the light reflected multiple times will penetrate the eyepiece and enter the eye, resulting in a lower contrast image, and the image will feel gray and foggy. Therefore, coating is needed to reduce reflection. By controlling the material of the film, the reflected light can be weakened or enhanced to achieve the effect of anti-reflection or anti-reflection, so as to increase the transmittance of the lens or prism and improve the observation brightness. However, for prisms that reflect light, the higher the reflectivity, the better, and coating is also needed to improve performance. Different lens functions require different coating solutions.

The professional knowledge contained in coating is difficult to explain and relatively boring. We will not talk about the specific optical principles. It is enough to understand the common coatings and be able to distinguish good telescopes. Common anti-reflection film colors are red film, blue film and green film; from the perspective of technology, it can be roughly divided into four types: full-surface single-layer coating (FC), multi-layer anti-reflection anti-reflection film and broadband film (MC) and full-surface multi-layer coating (FMC).