Infrared is widely used in military, artificial satellite, industry, health, scientific research, etc., so the problem of infrared pollution also arises. Infrared is a kind of thermal radiation, which can cause high temperature damage to the human body. Stronger infrared rays can cause skin damage similar to a scald, initially burning and then causing burns. There are several different cases of infrared damage to the eye. Infrared rays with a wavelength of 13000Å to 7500Å have a high transmittance to the cornea, which can cause damage to the retina of the eye. Especially the infrared rays near 11000Å can directly cause retinal burns without damage to the anterior media (corneal lens, etc.) of the eye. Infrared rays with wavelengths above 19000Å are almost completely absorbed by the cornea, causing corneal burns (turbidity, vitiligo). The energy of infrared rays with wavelengths greater than 14000Å is mostly absorbed by the cornea and intraocular fluid, and cannot penetrate the iris. Only infrared rays below 13000Å can penetrate the iris and cause iris damage. Long-term exposure to infrared rays may cause cataracts in the human eye.

 

Infrared rays can be manufactured artificially, and are also widely present in nature. They are also generated during the welding process, which endangers the welder's eye health; ordinary organisms will radiate infrared rays, and the macroscopic effect reflected is heat.

The reason for the generation of heat is the irregular motion of the particles that make up the matter. This movement also radiates electromagnetic waves, most of which are infrared.

 

1. There is almost no sunlight at night, but all materials on the earth radiate infrared rays, some are strong and some are calm. Infrared photography is to receive infrared rays emitted by various substances and then display them, but it does not take photos by emitting infrared rays.

2. Infrared perspective and night vision use different properties of infrared light respectively. The previous night vision is because the human eye cannot see infrared rays, but specially designed cameras and night vision devices are specially designed to accept infrared rays, so we feel that it is pitch black, but the camera can capture things. Because there is actually infrared everywhere, it's a bright light for infrared cameras and night vision devices.

Perspective uses infrared frequencies that are lower than visible light, and can pass through some fabrics (such as blended cotton and nylon) that visible light cannot pass through. Therefore, through a certain selection of filtering, the images behind these fabrics can be obtained.