Edwin Land and polarized light
As a boy, Land was fascinated by light. In particular, he was drawn to the natural phenomenon of light polarization.
Polarization refers to a physical property of light waves. As the waves move forward, they vibrate vertically, horizontally, and at all angles in between. A polarizer acts like a slatted screen, with long, thin, parallel openings. These invisible slats stop all angles of light except those parallel to the openings. By doing so, polarizers provide the ability to select light waves with particular orientations.
Natural polarizers were effective at reducing glare and measuring angles of reflectivity, but they were large and expensive. Land imagined important uses for synthetic polarizers, if they could be produced. Almost from the start of his work, around age 13, Land was searching for a product that would improve vehicle safety during nighttime driving: If polarizers could be placed in headlights and windshields, then they could be used to prevent the disturbing glare from oncoming vehicles’ headlights. Moreover, because glare would be eliminated, headlights could be made brighter, thereby increasing the safety of nighttime driving.
In 1926, Land enrolled at Harvard University to study physics, but his desire to conduct research caused him to leave after only a few months in search of more practical opportunities. He moved to New York City, where he studied physical optics independently at the New York Public Library and conducted experiments secretly at Columbia University. There, he worked to develop a synthetic polarizer.
Land’s experiments built on those of the British chemist and surgeon William Herapath (1820–1868). Herapath had sought, with little success, to produce large synthetic crystals that would mimic the natural crystals that were the most useful polarizers available at the time. Land recognized an alternative, and he worked to arrange a mass of microscopic crystals to produce the same effect. He created fine polarizing crystals, suspended them in liquid lacquer, and aligned them using an electromagnet. He then pulled a sheet of celluloid (a thin, clear plastic) through this solution to make a continuous sheet of crystals. As the lacquer dried, the crystals retained their orientation, and the result was a polarizing sheet that was thin, transparent, and pliable.
In 1929, Land applied for his first patent, a method for producing his polarizing sheets. He returned to Harvard in the same year but left again before completing his undergraduate degree to focus on his emerging business. By 1930, Land had identified a more promising way to manufacture polarizing sheets: Instead of using electromagnets, he could apply the tiny crystals to a plastic sheet and, by stretching it, achieve parallel alignment of the crystals. Although it took several years to perfect, this method resulted in the commercial production of polarized sheets.
In 1932, Land and George W. Wheelwright, III (1903–2001), a Harvard colleague, formed Land-Wheelwright Laboratories in Cambridge, Massachusetts, to manufacture polarizers. The company’s inexpensive polarizers were used in photographic filters, glare-free sunglasses, and stereoscopic products that gave the illusion of three-dimensional (3-D) images. 3-D movies were created by applying polarizers to projectorsand viewing glasses. The company also invented a new product called a vectograph that combined two still images taken from slightly different positions and printed as oppositely-polarized images; using polarized glasses, viewers saw a 3-D image of the subject.
In 1937, Land-Wheelwright became a public company named Polaroid Corporation after the trade name for the firm’s polarizing films. While Land’s dream of anti-glare vehicle systems was never implemented by automakers, the company was making a good business on polarizing films.
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