Basic Principles Of Sunglasses

High quality sunglasses are a very effective light regulator. Sunglasses can adjust external light to fit the human eye. In the next section, we will
We will introduce various techniques used by sunglasses manufacturers to adjust light. In order to better understand these technologies, it is necessary to first have some knowledge about light.
A beam of light has a certain amount of electromagnetic energy. The size of waves is measured by wavelength. The wavelength range of visible light is 400 to 700 nanometers. The energy of light waves is inversely proportional to their wavelength, and the shorter the wavelength, the higher the energy. In visible light, purple light has the highest energy and red light has the lowest energy, while ultraviolet light is above the visible light spectrum. In fact, natural light contains a large amount of ultraviolet radiation. Due to the high energy of ultraviolet rays, they can cause damage to your cornea and retina. What is glare?
The unit of measurement for brightness or intensity of light is lumens. For example, indoors, the intensity of most artificial light ranges from 400 to 600 lumens. If outdoors in bright sunlight, the brightness will fluctuate greatly, with a brightness of 1000 lumens in shaded areas, and 6000 lumens in places with large cement fields such as highways. Below a brightness of 3500 lumens, our human eyes feel very comfortable. When the brightness of direct or reflected light reaches 4000 lumens, the human eye begins to struggle to receive light. When we try to look at these bright areas, we only see white flashes, which are called glare. In order to reduce the discomfort caused by a large amount of light entering the eyes, we began to squint. Once the brightness reaches 10000 lumens, your eyes begin to completely filter out the light due to the received light being too strong. Exposure to such strong light for too long can cause damage, leading to temporary or even permanent blindness. On sunny days, a large area of snow can reflect light with a brightness of up to 12000 lumens. If we look directly at these lights without any protective measures, it will lead to "snow blindness".
Visible light is the light that the human eye can perceive. The visible light we see emitted by the sun appears colorless, also known as white light. In fact, it is composed of a mixture of colored light of multiple frequencies. All colored light mixed within the spectrum of visible light is colorless, i.e. white. (For detailed information, please refer to the principle of light).
We have two basic ways to see colors. One way is that an object itself can emit a certain frequency of light, for example, neon lights display colors in this way; Another way is for objects to absorb light of all other frequencies and only reflect light of a certain frequency, or to reflect light of multiple frequencies. These light waves are mixed and perceived as one color of light, such as painted objects displaying colors in this way. For example, to see yellow light, one way is for an object to emit light with a yellow frequency directly; Another way is to absorb the blue part of the spectrum and reflect the red and green parts of the light, which are mixed and perceived by the human eye as yellow light.