Choose the right sunglasses

Sunglasses to prevent sunlight intense stimulation caused damage to the human eye vision care products, sunglasses With the improvement of people's material and cultural level, but also as a special ornaments of beauty or reflect personal style.

Contains ultraviolet sun's rays reach the earth's surface, the cornea and lens of the human eye is most susceptible to UV damage eye tissue, and "cataract" is closely related eye diseases. Due to the increase in the environmental destruction of the ozone layer, as well as summer outdoor activities, the damage of ultraviolet radiation on the human eye can not be ignored. Wearing sunglasses is a better way, but pay special attention to the choice of sunglasses to protect the eye from UV damage.

In accordance with the provisions of the international standards, the sunglasses are classified as personal eye protection products category, because wearing sunglasses in the summer, the main function is to block the glare of the sun. However, the international standard sunglasses again subdivided into "fashion mirror" and "general purpose with a mirror." Relatively low standard of "fashion mirror" the quality requirements. Because "fashion mirror" main outstanding style, the wearer focus is decorated, rather than protection function. Standard of "general purpose with mirror" the quality requirements are more stringent, including UV protection, as well as diopter prism index requirements.

The pair of sunglasses looks very simple, there are two color glass or plastic that is in some kind of plastic or metal frame. What could be more simple? In fact, the two glass lenses can produce a lot of difference when you use sunglasses, these differences will you have a great. In this article, you will understand the differences that do exist between the various sunglasses. A good pair of sunglasses must have the following four functions:

Prevent sunlight UV irradiation:

UV can damage the cornea and retina, quality sunglasses can completely eliminate UV irradiation.

Prevent glare irradiation:

When the eye receives too much light, it will naturally shrink the iris. Once the iris shrink to limit state, then people need to squint. If the light is still too much, for example, snow reflects sunlight, will be on the retinal damage. Quality sunglasses can filter out up to 97% into eyes light in order to avoid injury.

Prevent glare irradiation:

Certain surfaces, such as water, can reflect a lot of light, and the highlights will disrupt the line of sight or hidden objects. Quality polarized sunglasses can utilize technology to completely eliminate such glare, we will introduce later polarizing technology.

Eliminate specific frequencies of light:

Certain frequency of light will blur the line of sight, and some other frequencies of light can enhance the contrast. Sunglasses to choose the correct color, to make it better in specific circumstances.

If the sunglasses do not provide UV protection, it will take you more exposure in the UV light. The cheap sunglasses filter out a portion of the light, causing your iris to open to receive more light. This also allow more ultraviolet light to enter, and increases the damage caused by ultraviolet rays on the retina. Thus, a variety of sunglasses indeed there is a difference. For the specific use of the environment, the selection of appropriate, high-quality sunglasses will provide maximum protection for you.

Sunglasses lens color determines the lenses can absorb part of the light spectrum which. Manufacturers use different colors to produce a specific effect of the use.

Common color gray is good, at the same time reduce the brightness, color distortion is minimized. Grey lenses provide glare protection, makes it the ideal choice for driving and general use.

Yellow or golden lens can reduce the blue, while allowing more light passes through the lens of the other frequencies. Blu-ray can rebound and dispersed a lot of light, and thus be able to produce a blue haze of glare effect. In fact, yellow can eliminate the blue portion of the spectrum, such that all objects appear to be bright and clear. This is why the anti-Snowblind sunglasses are generally yellow reasons. These colors make the color perception a little distortion, and therefore the kind of color sunglasses are not suitable for those who need to accurately identify the color of the activities.

Amber and brown are also a good general-purpose color. They can reduce glare effects, in addition to other than ultraviolet, its unique molecules can absorb higher frequency color, such as blue. Studies have shown that long-term near-ultraviolet light (such as blue and purple) irradiation, is one of the causative factors for cataracts. In fact, Sun Tiger have a special version called Blue Blockers, owns the patent. Such sunglasses with yellow lenses can cause color distortion, but it will increase the contrast and sharpness.

The green lenses FILTRATING part of the Blu-ray, can reduce glare effect. All color lenses, green lenses provide the highest contrast and visual sharpness, so popular.

Green or blue background, purple and rose-colored lenses can provide the best contrast of objects. Therefore, they are a good choice for hunting and water skiing.

Many sunglasses manufacturers use a process called constant density to the lens dyeing. This is the oldest sunglasses manufacturing process, the glass or polycarbonate mixture material have the same color. Thus such in the process of manufacturing lenses, the color is inside the lens. Molecular plating the surface of the pure polycarbonate layer absorbs light, but also a dyeing method. The most commonly used method is to a polycarbonate lens dyeing lenses were immersed in a special liquid containing a coloring substance, so that the coloring substance will be slowly absorbed by the plastic. If you want a darker, simply extend the lens immersed in liquid.

Polarization: lightwave from the sun and artificial light bulbs, etc., are vibrated in various directions and spread. Regardless of whether the light is being propagated, reflection, divergence, or refraction, when the light rays toward the direction of one or more planar vibration, we say that the light polarization. The polarization process can be naturally occurring, and can also be artificial excitation. Each time you observe see the glare when the lake is a natural example of polarization. Glare reflected from the surface of the lake is not able to pass through the lake "filter" light, which is why even though the lake is very clear and not be able to see objects under the lake.

The polarization filters are generally made up in a transparent plastic or glass surfaces by a layer of chemical film plating. Generally, the compounds used in the molecules between are naturally arranged in parallel. When they are uniformly coated on the lens, these molecules form a tiny lens, able to absorb all direction and they are arranged in the same light.

Forcing you must wear sunglasses, the vast majority of glare from a horizontal surface, such as the surface of the water and highway. When the light reaches the one surface, the polarization of the reflected light will be the same as the direction and angle of the surface. Thus, a high level of a reflective surface, such as lake, can produce a large number of the horizontal polarized light. Therefore, sunglasses polarized lenses are fixed at an angle, so that the only vertically polarized light can through the lens. You can observe this principle by the following method: wear polarized sunglasses, and then observed a horizontal surface, such as a car's hood. Head slowly to the left or right tilt. You will find that the glare from the surface will become bright as your line of sight angle adjustment.

Before buying, you can do a simple test to identify its authenticity. Find a reflective surface, and then took the sunglasses to observe the surface through a lens. Slowly rotate the sunglasses ninety degrees, the observed decrease or increase reflected glare. If the sunglasses are polarized sunglasses, you will see significantly reduce glare.

Aspects of sunglasses when exposed to sunlight below, the color will darken sunglasses or prescription glasses are called color glasses. Discolored glasses by Corning developed in the late 1960s, and by the Transitions companies in the 1990s to promote the use of. Lenses main principle dependent on the ultraviolet a special chemical reaction.

Photochromic lenses containing millions of molecules of certain substances (e.g., silver chloride or silver halide). When the absence of ultraviolet radiation, visible light can penetrate these molecules, while the visible light is artificial light, the general part. However, when exposed to ultraviolet sunlight, these molecules will pass through a chemical process, so that their shape is changed. The new molecular structure will absorb part of the visible light, so that the lenses darken. The number of molecules of the shape change will change with the change in intensity of the UV.

Specular reflection

The reflective sunglasses lenses as reflective like a mirror. The lenses are coated with a very thin layer of the reflective coating - Because this layer of coating is very sparse, so it is referred to as a half-silvered surface. The term "half-silvered" stems from the reflection of the lenses above molecular very sparse, and their number is only about half of the number of molecules in the opaque mirror lenses become. At the molecular level, the reflective elements are uniformly dispersed in the surface of the lens, forming a uniform layer of thin film, but only half of the lens area of ​​the film cover. Half of the silver side reflects about half the light to reach its surface, while the other half of the light directly through. Usually, the mirror coatings is gradual, gradually changing the coating color depth from top to bottom. This can strengthen the resilience of sunglasses from the top of the light, while allowing more light injection from below and horizontal direction. This means that when you are driving, sunglasses block the sun's rays at the same time, also allows you to see the instrument panel. Sometimes the coating is a dual gradient, the maximum depth of the color of the upper and lower portions of the lens the lens intermediate is clear. The reflective sunglasses key problem is that the coating can easily be scratched. Obviously, sunglasses manufacturers have not been able to successful in the reflective surface of the film coated with scratch-resistant layer. Thus, anti-scratch layer is coated on the surface of the lens, and the reflection film is coated on the anti-scratch layer.

Scratch resistant protective layer

Glass is a natural anti-scratch, but the vast majority of plastics are not. In order to solve this problem, manufacturers have developed a series of methods, the plated surface of the lens layer of transparent and strong film. The type of film is composed by the diamond-like carbon film and polycrystalline diamond sintered body substances. Through the ionization process, a thin layer, but very wear-resistant film is formed on the lens surface.

Anti-reflective coating

Sunglasses, a common problem emerges glare, glare back light to the back of the lens, and reflection to your eyes produce. The role of the anti-reflective protective coating is to reduce this lens light reflection. With scratch-resistant protective layer anti-reflective coating layer lens is very sturdy, thin film. The refractive index of the antireflection coating material from between the air and the glass. This makes the strength of the film inner surface and an outer surface of the reflected light is almost equal. When the wavelength of light from the film has a thickness of approximately one quarter, the light reflected from the surface of the film inside and outside, respectively will cancel each other by destructively interfere, thereby minimizing glare you see. The antireflection coating may also be coated on the front surface of the refractive lenses and sunglasses to eliminate lens reflective glare produced by the "hot spots".

Anti-UV coating

One of the causes of some of the most serious diseases of the eye: ultraviolet light. Depending on the frequency and wavelength of ultraviolet light was divided into two categories: UV-A and UV B.

Eye as a natural protection mechanism, the People of the cornea of ​​the eye can absorb all of the UV-B, and most of the ultraviolet A. However, there are still a part of the UV-A reaches the lens of the eye. Long to absorb UV-A may cause cataracts, a small amount through the cornea to UV-A reaching the retina can lead to macular degeneration, macular degeneration cause of blindness in elderly people over the age of 65. Long-term exposure to strong ultraviolet eyes cause cancer or actinic keratitis, retinal burns. This often happens in the winter snow, sunny outdoor snow surface reflective sun glare, which is usually known as snow blindness.

Sunglasses have a good anti-UV coating can eliminate ultraviolet radiation, you must ensure that your sunglasses to filter out 100% of two UV. Sunglasses should be indicated on the label of the sunglasses provide UV protection of the extent to which, and you need 100% protection.

The sunglasses of use and maintenance:

The New Share sunglasses to be adjusted by the staff before leaving comfortable to wear. Closing the mirror when you fold the glasses on the left foot.

Glasses wearing and Abstract, hands, grasp the temples, positive outward picked.

When not in use lens cleaning cloth, and placed in a special bag, beware of lenses and frames a hard object to scratch or squeeze a long time.

Frame or lens stained with dust, sweat, grease, cosmetics, and other warm water and clean with a neutral detergent, then dry soft cloth.

Prohibit water on for a long time, soaked in water and placed in fixed at exposure to sunlight; against the length of time the current metal edge.

Plate sunglasses used for some time, or set aside some time there may be a slight deformation is a normal phenomenon, the decision of the plate material properties. Dealer executive the rack adjustment can be restored as new.

Good maintenance of your glasses correctly, can be durable and lasting.