Most of the information received that a person perceives with the help of vision, and the eyes are able to work normally under very different lighting. However, with excess light, the eyes need to be protected. To do this, use sunglasses, which reduce the flow of light that reaches the retina and filter out the UV waves. Yes, with this task, these glasses deal successfully.
However, often the eyes are not prevented by the bright light itself, but its reflection in the surface of the water, snow, wet asphalt. Under these conditions, ordinary glasses, even with antireflective coatings, do not produce the expected effect – glasses with special polarizing goggles are required.
What is polarization?
In developing the polarization technology, the characteristics of the movement of a light wave were used.
It has been found that the highlights, which are reflected from the flat surfaces of light, in contrast to the ordinary rays of the sun, have a horizontal polarization, i.e. the light wave oscillations occur mainly in the horizontal plane. Therefore, if we use special filters that cut horizontally oriented waves and leave only vertically oriented, the brightness effect can be removed.
Then the polarizer filter
The main element of polarizing glasses is a polarizing filter – it is a thin film of liquid crystal located between layers of plastic or glass. Their molecules are oriented in a certain way, and between the columns of molecules are formed parallel vertical slits – optical axes, and light passes only through them.
The features of bias filters have long been used by professional photographers, varying with the help of color depth and contrast. Thus, a qualitative polarized photo-camera cuts up to 95% of polarized light.
The cost and quality of the glass depends on the materials they are made of, and the products of known manufacturers (Polaroid, Salmo, Ray Ban) will be more expensive than the unknown Chinese products. Buy a cheaper model, should be cautious: because the optical axis bias defect in their filters can be offset in relation to their operating position, and the benefits of these points will be slightly.
Today for the production of polarized glasses are used:
unknown to plastic science;
certified plastic (for example, with ANSI Z87.1 certificate);
special polymer CR-39;
other proprietary materials (ORMA, Trivex, etc.).
All of these materials have their own shortcomings and advantages.
As you can see, modern polymer models have less weight and greater impact resistance and as a result may be better than glass – and more expensive than them. If you choose low-cost glasses, they will not last more than a season, or even less. Although, in some cases, this is exactly what you need: for example, if you go skiing for the first time in a few years and years, do not plan on repeating this adventure.
Check polarizing glasses before or not, it’s quite simple: take two pairs of glasses and stack the glasses on each other at a 90-degree angle: the lens should be completely opaque. You can also look through the lens by rotating the glasses around your axis, on the phone screen, a calculator, a monitor – any LCD. When you turn 90 degrees, you should see nothing on this display.
Polaroid Polarization Polarization Layer
The latest models of polarized glasses are chameleon glasses, which darken or light depending on the lighting conditions, the ultraviolet content of sunlight and the ambient temperature.
Polarization glasses with dioptre are rare. This is due to the fact that, ideally, each pair of corrective glasses should be made individually, after which a polarizing filter is applied to the lens with diopters, and then the lens is obscured. Of course, the cost of a quality product will be quite high. Therefore, those who can not see the vision can wear glasses with a polarizer in conjunction with lenses or use polarizing coating for corrective glasses: these cushions are attached to the rim and, if necessary, fall on the glasses. Before lowering the liner, you need to wipe them carefully, and glasses of glasses, otherwise in the side light will be visible every grain of dust between the glasses and patches.