Polarized
lens technology is one of the most revolutionary applications of science and
optics that eliminates annoying glare and eye fatigue.
Basically,
Polarized eye candy for your eyes! After years of research and refinement, Polarized
was perfected by combining advanced polycarbonate technology and processes with
cutting edge coatings, turning conventional thinking on its head. Polar Polarized
ensures the complete and thorough elimination of glare, polarized light and harmful
UV rays and provides excellent eye protection. Its unique light absorption and
molecular properties enhance contrast and depth perception while maintaining
color integrity and minimizing eye strain.
Perceived
benefits include realized visual acuity, enhanced sharpness, reduced glare and
managed polarity. But don’t take our word for it, see for yourself.
Cutting-Edge Polarized Material
- Polycarbonate
injected at extraordinary pressure to maximize optical clarity and visual
acuity – eliminates eye fatigue and minimizes distortion.
- Unparalleled
protection – Polarized Polycarbonate is rugged (up to 5 times more impact
resistant than standard glass).
- Multi-layered
polarizing film and patented processing technology – enhanced, distortion
free vision and maximum polarized glare reduction.
- Lightweight
performance – significantly lighter than glass (perfect for athletes and
extended wear).
- 100% UV
Protection, blocks 99.9% of polarized light.
- Polarized lenses
are at the core of polarized platform and incorporate superior scratch
resistant protection, ultimate impact resistance and ultra lightweight
comfort.
Linear
polarizers
Linear polarizers can be divided into two general categories: absorptive
polarizers, where the unwanted polarization states are absorbed by the device, and beam-splitting
polarizers, where the unpolarized beam is split into two beams with
opposite polarization states
Wire-grid polarizer
A wire-grid polarizer converts an unpolarized beam into one
with a single linear polarization. Coloured arrows depict the electric field
vector. The diagonally-polarized waves also contribute to the transmitted
polarization. Their vertical components are transmitted, while the horizontal
components are absorbed and reflected. (This is not clearly shown.)
The simplest linear polarizer in concept is the
wire-grid polarizer,
which consists of a regular array of fine parallel metallic wires, placed in a
plane perpendicular to the incident beam. Electromagnetic waves which have a
component of their
electric fields aligned parallel to the wires induce
the movement of
electrons
along the length of the wires. Since the electrons are free to move in this
direction, the polarizer behaves in a similar manner to the surface of a
metal when reflecting
light; and the wave is reflected backwards along the incident beam (minus a
small amount of energy lost to
joule
heating of the wire).
[1]
For waves with electric fields perpendicular to the wires, the electrons
cannot move very far across the width of each wire; therefore, little energy is
reflected, and the incident wave is able to pass through the grid. Since
electric field components parallel to the wires are reflected, the transmitted
wave has an electric field purely in the direction perpendicular to the wires,
and is thus
linearly polarized. Note that the polarization
direction is
perpendicular to the wires; the notion that waves
"slip through" the gaps between the wires is incorrect.
[2]
For practical use, the separation distance between the wires must be less
than the
wavelength
of the radiation, and the wire width should be a small fraction of this
distance. This means that wire-grid polarizers are generally only used for
microwaves
and for far- and mid-
infrared light. Using advanced
lithographic
techniques, very tight pitch metallic grids can be made which polarize visible
light. Since the
degree of polarization depends little on
wavelength and angle of incidence, they are used for broad-band applications
such as projection.
Absorptive
polarizers
Certain
crystals,
due to the effects described by
crystal
optics, show
dichroism, preferential absorption of light which is
polarized in particular directions. They can therefore be used as linear
polarizers. The best known crystal of this type is
tourmaline.
However, this crystal is seldom used as a polarizer, since the dichroic effect
is strongly wavelength dependent and the crystal appears coloured.
Herapathite
is also dichroic, and is not strongly coloured, but is difficult to grow in
large crystals.
A
Polaroid polarizing filter functions similarly
on an atomic scale to the wire-grid polarizer. It was originally made of
microscopic herapathite crystals. Its current
H-sheet form is made from
polyvinyl
alcohol (PVA) plastic with an
iodine doping. Stretching of the sheet during manufacture
causes the PVA chains to align in one particular direction.
Valence
electrons from the iodine dopant are able to move linearly along the
polymer chains, but not transverse to them. So incident light polarized
parallel to the chains is absorbed by the sheet; light polarized
perpendicularly to the chains is transmitted. The durability and practicality
of Polaroid makes it the most common type of polarizer in use, for example for
sunglasses,
photographic filters, and
liquid crystal displays. It is also much
cheaper than other types of polarizer.
A modern type of absorptive polarizer is made of elongated silver
nanoparticles embedded in thin (≤0.5 mm) glass plates. These polarizers
are more durable, and can polarize light much better than plastic Polaroid
film, achieving polarization ratios as high as 100,000:1 and absorption of
correctly-polarized light as low as 1.5%.
[3]
Such glass polarizers perform best for short-wavelength
infrared light,
and are widely used in
optical fiber communications.
Beam-splitting
polarizers
Beam-splitting
polarizers split the incident beam into two beams of differing linear
polarization. For an ideal polarizing beamsplitter these would be fully polarized,
with orthogonal polarizations. For many common beam-splitting polarizers,
however, only one of the two output beams is fully polarized. The other
contains a mixture of polarization states.
Unlike absorptive polarizers, beam splitting polarizers do not need to
absorb and dissipate the energy of the rejected polarization state, and so they
are more suitable for use with high intensity beams such as
laser light. True
polarizing beamsplitters are also useful where the two polarization components
are to be analyzed or used simultaneously.
Polarization
by reflection
A stack of plates at Brewster's angle to a beam reflects off
a fraction of the
s-polarized light at each surface, leaving a
p-polarized
beam. Full polarization at Brewster's angle requires many more plates than
shown. The arrows indicate the direction of the electrical field, not the
magnetic field, which is perpendicular to the electric field
When light reflects at an angle from an interface between two transparent
materials, the reflectivity is different for light polarized in the
plane of incidence and light polarized
perpendicular to it. Light polarized in the plane is said to be
p-polarized,
while that polarized perpendicular to it is
s-polarized. At a special
angle known as
Brewster's angle, no
p-polarized light is
reflected from the surface, thus all reflected light must be
s-polarized,
with an electric field perpendicular to the plane of incidence.
A simple linear polarizer can be made by tilting a stack of glass plates at
Brewster's angle to the beam. Some of the
s-polarized light is reflected
from each surface of each plate. For a stack of plates, each reflection
depletes the incident beam of
s-polarized light, leaving a greater
fraction of
p-polarized light in the transmitted beam at each stage. For
visible light in air and typical glass, Brewster's angle is about 57°, and
about 16% of the
s-polarized light present in the beam is reflected for
each air-to-glass or glass-to-air transition. It takes many plates to achieve
even mediocre polarization of the transmitted beam with this approach. For a
stack of 10 plates (20 reflections), about 3% (= (1-0.16)
20) of
the
s-polarized light is transmitted. The reflected beam, while fully
polarized, is spread out and may not be very useful.
A more useful polarized beam can be obtained by tilting the pile of plates
at a steeper angle to the incident beam. Counterintuitively, using incident
angles greater than Brewster's angle yields a higher degree of polarization of
the
transmitted beam, at the expense of decreased overall transmission.
For angles of incidence steeper than 80° the polarization of the transmitted
beam can approach 100% with as few as four plates, although the transmitted
intensity is very low in this case.
[4]
Adding more plates and reducing the angle allows a better compromise between
transmission and polarization to be achieved.
Birefringent
polarizers
Other linear polarizers exploit the
birefringent
properties of crystals such as
quartz and
calcite. In these crystals, a beam of unpolarized light
incident on their surface is split by
refraction
into two rays.
Snell's law holds for one of these rays, the
ordinary
or
o-ray, but not for the other, the
extraordinary or
e-ray.
In general the two rays will be in different polarization states, though not in
linear polarization states except for certain propagation directions relative
to the crystal axis. The two rays also experience differing
refractive
indices in the crystal.
A
Nicol
prism was an early type of birefringent polarizer, that consists of a
crystal of calcite which has been split and rejoined with
Canada
balsam. The crystal is cut such that the
o- and
e-rays are in
orthogonal linear polarization states.
Total internal reflection of the
o-ray
occurs at the balsam interface, since it experiences a larger refractive index
in calcite than in the balsam, and the ray is deflected to the side of the
crystal. The
e-ray, which sees a smaller refractive index in the
calcite, is transmitted through the interface without deflection. Nicol prisms
produce a very high purity of polarized light, and were extensively used in
microscopy,
though in modern use they have been mostly replaced with alternatives such as
the
Glan–Thompson prism,
Glan–Foucault prism, and
Glan–Taylor prism. These prisms are not true
polarizing beamsplitters since only the transmitted beam is fully polarized.
A
Wollaston prism is another birefringent polarizer
consisting of two triangular calcite prisms with orthogonal crystal axes that
are cemented together. At the internal interface, an unpolarized beam splits
into two linearly polarized rays which leave the prism at a divergence angle of
15°–45°. The
Rochon and
Sénarmont
prisms are similar, but use different optical axis orientations in the two prisms.
The Sénarmont prism is air spaced, unlike the Wollaston and Rochon prisms.
These prisms truly split the beam into two fully polarized beams with
perpendicular polarizations. The
Nomarski
prism is a variant of the Wollaston prism, which is widely used in
differential interference
contrast microscopy.
Thin film polarizers
Thin-film linear polarizers are glass substrates
on which a special
optical coating is applied.
Interference effects in the film
cause them to act as beam-splitting polarizers. The substrate for the film can
either be a plate, which is inserted into the beam at a particular angle, or a
wedge of glass that is cemented to a second wedge to form a cube with the film
cutting diagonally across the center.
Thin-film polarizers generally do not perform as well as Glan-type
polarizers, but they are inexpensive and provide two beams that are about
equally well polarized. The cube-type polarizers generally perform better than
the plate polarizers. The former are easily confused with Glan-type birefringent
polarizers.
The History of Polarized Sunglasses
People have realized the importance of keeping the sun
from your eyes for thousands of years. Primitive versions of sunglasses have
been found around the world.
People have realized the importance of keeping the sun from
your eyes for thousands of years. Primitive versions of sunglasses have been
found around the world. Most notably were the smoke tinted glasses worn by
Chinese judges in the 14th century. The reasons for wearing sunglasses,
however, have changed. Today, we now know that sun rays have UV and blue light
which can cause long-term and short-term eye problems. They include cataracts
and even forms of eye cancers.
Modern-day sunglasses were first created in the late 1920s by Sam Foster, who
sold them in Atlantic City, New Jersey. They soon became popular among the
general population, celebrities, and the military. In fact, the Army
commissioned an optical firm to create special sunglasses for their Air Corps
pilots to protect their vision while they were in the sky.
Polarized sunglasses were first made in the late 1930s by the Ray Ban company
as an anti-glare aviator sunglass. The sunglasses were made in a specially
designed shape to give the pilot’s optimal shade from the sun as previous
designs allowed some light in when the pilot looked down at their instrument
panel. The glasses were given to all pilots free as a part of their uniform. A
year after they were made, the polarized sunglasses became available for
purchase for the general public.
Polarization in sunglasses is a popular feature in sunglasses now. They are a
predominating favorite among people who spend a lot of time around the water.
The polarized lens reduces the glare from the reflecting light in the water.
The polarization is applied to sunglasses in three different ways. The cheapest
method is to have a film of polarized filtering applied to the outer coating of
the sunglasses. The filter can also be placed between the lens’s layers. The
most expensive and newest way is to combine the filter with the lens material.
This process is done by adding the filter to the lens while it is still liquid.
It delivers the highest visual quality.
Polarized sunglasses have now become the name of quality with specification it
has but they had a history behind their popularity. The Roman emperor Nero
watched gladiator flights with the help of emeralds. Chinese in 12 century used
flat panels to protect their eyes. But now people use tined lens. This effort
was made by James Avscough in mid 18 century.
Polarized sunglasses first introduced in 1936 by Edwin H. Land. He used to make
patented Polaroid filter to make these sunglasses as an effective protective
cover against harmful rays and light glare. He further explain his work with
the rule of light passing through these lens in single plane and this make the
sunglasses to eliminate the rays of glare from actual light rays. Normal
sunglasses allow to pass light in many planes and they cannot minimize the
glare effect of light on your eyes but only polarized sunglasses.
This was just beginning of the industry now know as polarized sunglasses
industry. The best brands for these sunglasses are ray ban, Gucci, Prada .
Browse through our stellar collection of lenses and frames for women and you’ll
see the oversized designer sunglasses that look deliciously different on the
well-known celebrities that look for them as often as you do. after all,
looking good in the sun isn’t just a matter of good skin tone or a fancy
wardrobe. You need to accent your face with eyewear that compliments everything
else well. this is why we carry a wide selection of the most popular styles
from companies like bvlgari, giorgio armani, christian dior, tom ford, and many
others.
These aren’t cheap copies of designer sunglasses either. What good is wearing a
name-brand eyewear manufacturer if you aren’t wearing the real thing, the
styles that are exclusively original, with all the premium elements including
the familiar temple logo designs you see so often.
still, focus online creates value by working with these companies to find the
best deals of sunglasses and eyewear within their outstanding collection of
accessories. These are savings we pass on to you, so that you can enjoy a look
that turns heads when you venture outdoors for a little fun in the sun.
Designer sunglasses are something you shouldn’t have to worry about, and our
endless choices help take some of the guesswork out of knowing whether you’re
getting styles and materials you can trust. so, if you want to capture a look
that’s hot for her, take the time to browse our best models and find one that
speaks to you.
at focus online, we know guys look great in polarised sunglasses , and guys
like to show off a quality pair of glasses that are hot for him when he’s
outside in the sun. Sex appeal is an important component of men’s eyewear,
because it reveals something about the character of the guy who’s wearing a
particular pair of lenses, a particular style of frame.
Protecting your eyes from the harsh rays of sunlight is another consideration
for anyone looking into polarised sunglasses. Spending time outside shouldn’t
be hazardous to your health, and that’s why we only select brands and styles
that adhere to some pretty high standards in terms of uv protection. Beyond the
urge to look “cool,” the best brands’ sunglasses create a whole new look for
you, one that usually matches your personality or a quality of your character
that makes each pair uniquely your own. it’s like having a signature style that
says, “this is who i am, and i’m proud of it.” that’s the feeling you connect
with when you find a pair of polarised sunglasses that suits your style. With
over 300 pieces of quality men’s eyewear to choose from, you won’t have trouble
finding something you like. What’s more, we have the brands that men ask for
most often, like carerra, persol, marc jacobs, oakley, and ray ban. Our men’s
collection of polarised sunglasses cover a wide range of outdoor activities,
and the quality of these original frames and lenses is beyond compare. see for
yourself why focus online has become a trusted name in online eyewear over the
last few years. Notice how well the colours and styles of each vendor’s product
line blend in with today’s “hot for him” fashions. Our job is to help you
create a look that shows the world who you really are, and our commitment to
bringing you the latest styles and widest selection makes that job easier for
you, the customer.
For More detail visit our websites:
http://www.focus-online.com/mens/carrera-sunglasses.html
http://www.focus-eyewear.co.uk/
Why have we chosen ray ban sunglasses as part of our growing collection of
designer lenses for women? it’s not hard to understand, once you know the
facts. ray ban is one of the most respected names in performance-
level
eyewear for active lifestyles and sports enthusiasts. There’s a healthy bit of
technology that goes into making premium lenses and frames for this type of
audience, but as you know, we’re more interested in turning heads with fashion
statements rather than engineering details. Therefore, it makes sense that we’d
want the brands we feature to look good on people.
http://www.focus-
eyewear.co.uk/
