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A small company, in a small town, in the United States, is leading the way in one of the 'hottest' sectors of the optical business, polarised sunglass lenses.
International Polarizer with only 14 employees in the town of Marlborough, Massachusetts, produces over one million square feet of polariser sheet annually, and expanding all the time. The majority of the 14 employees are engineers and professionals who set up the process and monitor it for quality. Although small in size, International Polarizer as the name implies, is an international company. Its largest market is in Asia, closely followed by the United States and Europe. International Polarizer was started in 1985 by Dick Phillips, a professor of physics and electrical engineering. Dick has a PhD in physics from the University of Michigan and is an expert in the transmission of light. He worked in the optical business for several years at Foster Grant, a major supplier to the over the counter sunglass market. When both Foster Grant and American Optical, who also made polarised sheet and sunglasses, either faltered or gave up the sunglass business entirely, Dick saw an opportunity. At that point in time there was only one major supplier of polarised sheet left: Polaroid made sheet primarily for use in their own sunglasses. International Polarizer does not make or sell sunglasses; it is the largest supplier in the world of polarised sheet to the open market. Dick, who has a strong entrepreneurial spirit, after leaving Foster Grant, looked for a location to start his own business. He found the building where International Polarizer is presently located and started the company. The making of polarised sheet, although a well-established process, is not easy to do. In the past, for various reasons polarised lenses were never well understood by the dispenser and never very popular in prescription eyewear. Today that situation is changing as more lens makers and sunglass manufacturers are educating the dispenser and the public to the benefits of polarization. Moreover, it is in the area of prescription sunwear that polarised lenses are getting a lot of attention these days. For polarised lenses, when used in a correct setting, make a dramatic difference to the wearer. Sunglass manufacturers who produce inexpensive drugstore variety sunglasses or fitovers can convert the polarised sheet into lenses, cutting it into the individual shapes they desire. Higher priced sunglasses use the thicker sheet and cut and form it in designer frames as plano sunglasses. The purpose of polarised lenses is to reduce 'glare', an over abundance of reflected light. Light when it is being reflected off of any surface is scattered and creates a glare that limits vision and creates a washed out perception of colour. Ordinary sunglass lenses reduce the amount of light transmitted to the eye in proportion to their darkness, but do not reduce glare. Glare, being reflected light, is light scattered in all directions, unlike transmitted light coming from a particular source, the sun. Reflected light coming off of a horizontal surface is the best example of glare. Water provides a perfect example of just such a horizontal surface. With polarised lenses it is possible to eliminate the reflected glare and see below the surface of the water. That is why polarised sunglasses are the fisherman's best friend. Glare coming off of other surfaces is reduced also, but at different efficiencies depending on the shape and orientation of the surface reflecting the light. Polarization in sunglass lenses gives a very demonstrable and dramatic effect to the viewer. When it is combined with UV and blue blocking it makes an excellent sunglass lens, reducing strain and fatigue on the eye and allowing for sharper more pleasant and comfortable vision. Not many people have the know how, technology, and machinery to compete in this complicated field. Dick, using many of his own ideas, developed machinery and a process that yields high quality high performance polarised sheet. The efficiency of the polarization is claimed to be 99 per cent plus (Dick says nothing is 100 per cent). The factory is small, compact and neat. It consists of the business office, a research and development laboratory, a process and quality control area and the machinery to make and colour the polarised sheet.
The sheet is made up of many layers of plastic and coatings (as many as 17) in effect laminated together.There is a carrier sheet of plastic material that becomes the polariser film. Then the film is encapsulated in layers of plastic and scratch resistant coatings that make up the polarised sheets.
Wide rolls of material run through the process in batches producing the polarised sheet in the different colours and thicknesses that the company makes. The sheet is dyed to different colours, dark grey being the company's and the world's most popular. In addition the company makes as standard colours, medium brown (its second best seller), medium grey, retina-guard (greenish grey), blue glare-guard (a 96 per cent blue light blocker), sportsmen's yellow (brown/yellow), haze fighter, and vermilion.
The wide rolls are placed on a slitting machine and slit into rolls of 17in x 400ft, or standard rolls 52mm, 60mm, and 71mm wide to accommodate the various sizes needed for sunglass lenses. International Polarizer also forms wafers in different base curves (i.e., 6.00D, 4.00D.) to be used by the plastic lens casters in making polarised ophthalmic lenses. In this case the wafers are baked out from the polarised sheet and moulded into either a semifinished or finished lens with CR-39 or some other monomer cast around it.
In order to explain the process of manufacturing polarised sheet Dick uses the analogy of a plate of spaghetti. The base sheet of plastic that is usually poly vinyl alcohol is like a plate of spaghetti with the molecules all scrambled up. The PVA sheet is then 'stretched', causing the molecules to all line up in parallel like pieces of spaghetti straightened out lying next to each other. Iodine crystals that are poured onto the PVA sheet run down in the channels between the lined up molecules. This creates the polarised sheet that can be thought of as a kind of venetian blind, only allowing the light through in one axis. In mounting sunglass lenses that axis is always mounted along the horizontal or 180° axis. As these facts are better understood and as the quality and variety of polarised lens products available increases, the demand for polarised lenses increases. International Polarizer, as a small company in a small town, is happy to continue to play a leading role in filling that demand. |