Sol-Grid: The Next Wave in Polarized Lens Technology
What is polarized light?
When light waves are reflected they becomes polarized. To the eye this is seen as glare. Only polarized lenses can block or absorb this blinding glare.
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1928 - The “low tech” solution - PVA film
Current polarized lenses are constructed by laminating, molding or embedding a thin-film polarizing filter within a glass or optical plastic lens substrate. Today’s polarizing film technology is essentially the same as it was over 80 years ago when Edwin Land discovered a way to cheaply produce a film that would absorb polarized light and reduce glare. This “polarizing film” is made from polyvinyl alcohol (PVA) plastic (think, clingy food wrap) dyed with iodine or other dichroic materials.
Stretching the plastic film aligns these dichroic dye (iodine) molecules generally in the same direction to form a pattern of parallel lines. This pattern or “grid” becomes the polarizing filter. When reflected polarized light or glare strikes the filter the aligned molecules in the film absorb (block) light in that particular direction, eliminating the glare. This was a great advancement in the field of optics 80 years ago, but this “low tech” solution has limitations.
Problems with current polarized lens technology
Today’s polarized lenses only work effectively when the lenses are dark (high density) and are on "low base" curve or flat substrates. The iodine/dichroic dyes that enable the absorption of polarized light are in fact dark in color and thereby also block a significant amount of useful visible light. PVA based polarizers must be tinted in order to absorb glare.
Other problems associated with conventional methods of polarized “sun- lens” manufacture is the inconsistent or non-uniform stretching of the polarizing film material (PVA) as well as the warping of the film when laminated and thermoformed or “bent” and cast to the desired base curve of the lens. When producing a lens with this method the laminated material is heated and “bent” over a form. This thermoforming process induces stress into the materials and deforms the “parallel” grid or line pattern which produces the polarizing filter. The parallel pattern of molecules which were formed by stretching the film in one direction are warped out of alignment which makes the polarizing filter far less efficient and introduces aberrations and artifacts into the lens, creating an undesirable, inconsistent polarizing filter across the field of view which can be distracting and dangerous for the consumer making this method inherently “unpredictable".
This undesirable effect is also noticeable in cast CR39 lens blanks as seen here. (see image below of actual sample) Note the "bent" edges of the film. The polarizing filter grid lines follow this arc and therefor the azimuth does not remain in parallel alignment.
Another problem associated with the current manufacturing process is waste. This type of production is not a precise or efficient method of manufacture, i.e.: Stretching a thin “cling wrap” type material uniformly and consistently is problematic and produces an undesirable amount of waste materials which translates to an increase in costs.
These inconsistencies and lack of predictability lead to lower yields and higher levels of waste from defects in the manufacture of “film” based polarizing filters. In short, Low Tech equals Higher Costs, Unpredictability and Waste. In addition, with today’s PVA film based polarizers, it is impossible to compensate for the base curve of the lens and adjust the filter to yield a consistent polarizer across the entire field of view.
2010 - The "high tech" solution - film-less polarizers
The Sol-Grid polarizer is a state of the art nanotechnology precisely generating the polarizing pattern or "grid" of nanowires directly on the lens substrate so there is no need for film. Sol-Grid applies the pattern in perfect alignment, compensating and correcting
for lens geometry while maintaining perfect azimuth across the entire field of view. Sol-Grid technology can be applied to virtually any lens substrate or geometry including high base, asymmetric, spherical, toric and lenses and shields.
Jumping out of the box
Sol-Grid polarization technology is a quantum leap in the field of polarization. Sol-Grid technology is a high efficiency film-less polarizer that provides superior polarization, maintaining perfect azimuth and achieving an industry first tint-less (virtually clear) polarized lens. Sol-Grid has been awarded a patent #US7771045 marking the first major breakthrough in polarized lens technology in almost a century with exceptional levels of polarizing performance and visible light transmittance. In addition, Sol-Grid allows possible applications where conventional polarizing films simply can not such as gradients and multi-zone polarizers.
Sol-Grid Polarized: Getting Wired
It's not rocket science... it's harder!
While the rest of the world is going wireless, we are getting wired. Nanowires to be precise. Nanowires are sub-wavelength structures so small that more than 1500 of them could be stacked on top of each other and still not equal the diameter of a human hair.
In fact, Sol-Grid nanowire structures used to form our polarizing grid are so small that the width of only 30 strands of DNA placed side by side would "almost" equal the height of just one nanowire.
Sol-Grid is the world's first “film- less” polarized lens technology, eliminating the need for PVA film and all the problems associated with it. Instead, Sol-Grid imprints a sub-wavelength nanowire grid directly on any substrate or lens geometry in precise alignment, optically corrected and oriented for perfect azimuth across the entire field of view.
Sol-Grid Technology: 1 concept - 2 methods of manufacture
Method One: Thermoformed Laminate
The first method, Sol-Grid 1 is a "bridge" technology taking advantage of the existing manufacturing capabilities of current factories. Sol-Grid 1 is a laminated product incorporating a pre-distorted nanowire grid imprinted directly on the laminate
compensating for the end product geometry and aligned so that after thermoforming the lens blank will exhibit perfect azimuth across the entire field of view. (see image below)
(pre-distorted nanowire grid pattern)
Method Two: Preformed Imprinted Lens Blank (molded or cast)
The second method, Sol-Grid 2 directly imprints the preformed lens substrate with sub-microscopic nanowires in precise alignment, optically corrected and oriented for perfect azimuth directly on any lens geometry. Sol-Grid 2 can be applied on either the concave or convex surface and may also be placed in the center of a spherical laminate. (see image below)
How does Sol-Grid do it?
The Sol-Grid polarizer is produced by an advanced form of micro-lithography, nanoprinting or laser micromachining. The major advantage of the Sol-Grid process is that the nanowire’s directionality and configuration can be precisely controlled.
In conventional polarizers, the directionality of the polarizing material is affected by the heating and stretching of the PVA polymer film. Due to this “stretching” method, there is no way to produce anything but “somewhat” parallel wires which can get out of alignment in the thermoforming production process of conventional polarizing sun lenses.
Sol-Grid technology enables the manufacturer to precisely apply a Sol-Grid polarizer to virtually any lens geometry suitable for consumer optical requirements while correcting for the base curve and power of the lens, maintaining perfect azimuth; which means a more efficient and effective polarized lens with no distortions or aberrations across the entire field of view, even on high base curves.
Other advantages of Sol-Grid polarizers include design options Edwin Land couldn’t even imagine and are impossible with conventional polarized technology such as partial, area and gradient polarized lenses, low density/ tint-less lens designs, multi and variable axis polarizers.
Due to this precise and predictable manufacturing process, the Sol-Grid Polarizer is a superior method of manufacture generating better yields with far less defects and waste, providing exceptional polarizing performance, manufacturing ease and design flexibility, while lowering the costs of production.
S&P Waves
Unpolarized light has both s and p polarization. Light having s-polarization, with a polarization axis that is parallel to the nanowires is reflected from the surface of the Sol-Grid polarizer.
Light having orthogonal polarization or p-polarization is transmitted through the nanowire grid and substrate achieving large contrast ratios and highest visible light transmission possible.
Customizable Performance
Sol-Grid polarized technology offer improved contrast ratios, maximum glare reduction and high visible light transmission with unparalleled versatility. Choose from high density dark sunlenses or low density tint-less lenses perfect for any polarized Rx application. In addition Sol-Grid includes a built in AR treatment that can not wear off and is 98% (est.) effective in reducing rear reflection as well as superior IR and UV protection depending on the substrate and desired performance characteristics.
The Rx Option
Sol-Grid polarizers can be applied to virtually any lens geometry or prescription. Sol-Grid is not limited by base curve or power since the azimuth can be corrected for any lens design. Sol-Grid makes Rx polarized practical. Sol-Grid is the first and only polarized technology that has the potential to produce a tint-less virtually clear polarized lens!
In Production
Sol-grid utilizes existing injection molding and lens coating manufacturing techniques and equipment. Sol-Grid technology eliminates the use of the PVA film, thereby eliminating the dependence on limited supplies from the few factories that manufacture this outdated material. Sol-Grid eliminates the waste and uncertainty of production yields and costs by providing a precise, predictable and repeatable manufacturing process.
In the Market
Sol-Grid offer unique marketing opportunities. Exclusivity, unequaled performance and versatility with customized performance to meet modern consumer demands. The Sol-Grid process allows the manufacturer to specify the features and characteristics of the lens product to suit their client’s needs. Mirrors, coatings, tints, variable densities, photochromics, these are just a few of the possible variations of Sol-Grid polarized lenses.
Why Sol-Grid Polarized?
Polarized lenses offer the consumer greater comfort and reduced eye strain. Given Sol-Grid's superior quality, performance and unique industry first film-less and tint-less characteristics, Sol-Grid technology offers exciting and unique marketing opportunities in both sunlens and Rx. We think the choice is crystal clear.
Sol-Grid polarized lens technology. Simply the most advanced polarized technology available anywhere.
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