What are the strange phenomena when wearing a polarizer?
How does a polarizer work?
We all know that light travels in straight lines, and that's the particle nature of light. At the same time, light also travels in the form of a wave, which is the wave of light, so light has wave-particle duality, which is called a light wave. Lightwave has a vibration in all directions, and the direction of vibration of the reflected light will be deflected. Polarized lenses take advantage of this. The core of the polarized lens is polarized film. Polarizing films are dichroic, and transparent films that allow light to pass parallel to the direction of the optical axis, while light perpendicular to this direction is absorbed. This phenomenon is called polarization of light. The light that passes in the same direction of vibration is called polarized light. The reflected light is absorbed because it is perpendicular to the transmission axis of the polarizing film after being reflected. Polarized lenses use this principle namely, to eliminate very effectively strong reflection light and scattered color light, making the light becomes downy, so the scene that the human eye sees is clear and natural.
To persuade people to buy polarizers for sunglasses, Dr. Land rented a hotel room and placed a fish tank on the windowsill. Its goldfish disappearing in the late afternoon sun. Dr. Land called over the general manager of American Optical to meet, handed each of them a piece of the polarizer, and goldfish were immediately visible. Dr. Land told them that they should be using polarized lenses for sunglasses from now on, and American Optical took his advice. To this day, opticians still do similar tests when they show customers the wonders of polarized lenses.
The function and roles of polarized lenses
Since polarized lenses have such a unique design principle, then in life, what function does it have? Polarized lenses can reduce glare. It can be worn while driving, fishing, skiing, water skiing, or cycling to improve the clarity of the field of vision. Polarized sunglasses can also improve visual comfort for patients undergoing cataract surgery and the elderly who are sensitive to light. Polarized lenses have limitations: While driving, be aware that digital displays such as LEDs, GPS, and cell phone screens in the car may not be visible with polarized glasses. Therefore, polarized sunglasses should not be used for pilots, crew.
Why do you see a rainbow when you wear polarizers?
After buying polarized sunglasses, some people will say: Put them on to look at the windshield of a car. It shows a rainbow. In fact, this is a normal phenomenon, which proves that the lens is polarized light. Because some car glass has film. Car film is generally metal film, and if the metal film is not smooth enough, polarized sunglasses will produce stripes or rainbow. Better quality car film will not. Another possibility is that the car's film is not well affixed, there are some small bubbles that can not be seen with the naked eye. When light is refracted with a polarizer, spots or colored light appear.
Why are some very expensive designer sunglasses not polarized?
When introducing the kind of sunglasses, everyone should already know that polarized sunglasses are only a kind of sunglasses and do not represent the "best" sunglasses. Polarized sunglasses have disadvantages in some areas. For example, the color is not rich enough, and the materials of the lenses are limited. Some fashion brands, while ensuring that the protective effect of sunglasses, give more attention to decorative function, so the lenses are not polarized lenses. At the same time, some brands, such as Gucci, BOSS, Zegna, Rayban, and so on, will have models with or without polarized lenses, for users with different needs to choose from.