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Polarization is a phenomenon which verifies transverse nature of light and all other electromagnetic waves. Polarization is firm evidence of this transverse nature. An ordinary beam of light consists of a large number of waves emitted by the atoms of the light source. Each atom produces a wave having some particular orientation of the electric field vector E, corresponding to the direction of atomic vibration. The direction of polarization of each individual wave is defined to be the direction in which the electric field is vibrating.
Polarizing sheets
A polarizing sheet (rather, light polarizing sheet) made up of a sheet of a polymer, especially a phenoxyether polymer, laminated at least on one surface of a light-polarizing film and a transparent conductive layer formed by vacuum metal evaporation etc. on a surface of a film or sheet to the light-polarizing film, wherein the film or sheet has specified ranges of retardation value, heat distortion temperature, average visible light transmittance, water vapor permeability, Izod impact strength and degree of swelling in solvents. Polarizing sheet must have following physical properties:
1. Retardation value: not more than 30 millimicrons;
2. Heat distortion temperature: not lower than 80° C.;
3. Average visible light transmittance: not less than 75%;
4. Water vapor permeability: not higher than 30 g/m2 ; 24 hr.;
5. Degree of swelling on a surface in a solvent: not more than 0.5%.
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Waves and Optics