Optical color wavelength eyes

There are two major photosensitive cells in the human retina: rod-shaped cells and cone-shaped cells.

Rod-shaped cells are responsible for low-lighting visual perception, can feel the size and shape of the object, and cone-shaped cells ensure color perception.

There are three types of cone-shaped cells. The peak photosensitivity values of cone-shaped cells are red, green, and blue in the spectrum, but they all have weak responses to other visible bands. There are 7 million cone-shaped cells in human retina flat, most of which are red and a few are green, the "blue" cone-like cells have the least

There are three kinds of unnecessary photosensitive cells in the retina of the eyes, namely red blood cell, green cell and Blue Cell, which respectively contain red-sensitive visual pigment, green-sensitive visual pigment and blue-sensitive visual pigment. The three optical pigments are sensitive to red, green, and blue light respectively. After receiving the intense stimulation of three different light colors, the red, green, and blue visual signals are generated respectively. Light of other colors can stimulate these cells to different degrees and generate different color signals. When the three color sensing cells are stimulated to the same extent, they produce white signals. After comprehensive analysis of the visual neural system, these color signals will produce different colors in the visual center of the brain. People with normal colors can distinguish over one hundred different colors.

The color of an object is determined by the color of the light reflected after the light is directed to the object. The color of the reflected light is related to the nature of the substance, depending on the wavelength of the main absorption range of the substance, which wavelengths are reflected.

For example, when a white light is shining on an object, if the object reflects almost all the light, the three photosensitive cells (red, green, and blue) in the eyes receive a color of approximately equal intensity, in our minds, we feel that this object is white.

If the object absorbs almost all incoming light and no light reaches the eyes, the three photosensitive cells are not stimulated, and the object is black.

If the object absorbs a large amount of light that is not in the red color range, the reflected light is almost red, and only the red photosensitive cells feel the light signal,
Blue and green photosensitive cells are not sensitive to this light (poor response), so we can see red objects in our minds.

The penetration ability of electromagnetic waves is related to the frequency. For example, X-rays are also related to many factors. Generally, they have high frequency Penetration ability, low frequency Penetration ability, and strong diffraction ability.

The 850nm infrared filter indicates that the filter blocks the incoming light from the 850nm band and only allows the incoming light from the 850nm band. This blocks the visible light and the infrared light below the 850nm wavelength.

Infrared: http://qicai.fengniao.com/219/2198095.html#2

Infrared video: http://qicai.fengniao.com/topic/2196147.html

The infrared wavelength is long, the diffraction effect is obvious, and the penetration capability is poor. The thermal effect is obvious.

Ultraviolet rays and infrared rays have the opposite characteristics in these directions. The ultraviolet rays have short wavelength, poor diffraction effect, strong penetration ability, low thermal effect, and obvious chemical effect. Therefore, UV disinfection is usually used instead of heating.
Color Sunglasses: mainly rely on the absorption of light to reduce the intensity of sunlight. Add different colored compounds to the glass to make sunglasses of different colors, and they absorb different wavelengths of light. Coated Sunglasses: glass lenses are coated with a layer of metal film, relying on the lens reflection of the sun to protect the eyes.