Polarisers are used to analyse or create polarised light. Using a dicroitic polymer sheet base, we can offer a wide range of options including sizes, polarisation and light transmission.

Common applications:

  • Contrast enhancement display filters
  • Sunlight readable touch screens
  • Photography
  • Stress analysis of glass and plastics
  • Optical sensors and safety light curtains
  • 3D projection systems
  • Ophthalmology

The original material, patented in 1929 and further developed by Edwin Land as the H-type, is a polyvinyl alcohol (PVA) polymer impregnated with iodine. During manufacture, the PVA polymer chains are stretched such that they form an array of aligned, linear molecules in the material. The iodine dopant then attaches to the PVA molecules, making them conductive along the length of the chains. Light polarised parallel to the chains is absorbed, and light polarised perpendicular to the chains is transmitted.

The H-type technical range of polariser was made by Polaroid up until December 2004, when the former owners of 3M closed the production of iodine based polariser material.

With extensive experience and knowledge in the field of iodine based polariser, Optical Filters was a long-standing and value added reseller for Polaroid. Although these polarisers have been retired, we continue to source and manufacture the best quality PVAL based technical polarisers such as, linear and circular polarisers as alternatives to the old Polaroid range. We also offer new variations to suit modern applications and markets.

In addition to the supply of the filter material in sheets, we offer full manufacturing service to cut and finish parts to final size. Full optical lamination in glass and plastic is also available.

Un-polarised light is a complex mixture of random wavefronts transverse to the line of travel. Linear polarizing filters selectively absorb light vibrations in certain planes. When light passes through a linear polariser, its vibrations are confined to a single linear plane.

A circular polariser is a combination of a linear polariser and a ¼ wave retarder oriented at 45° that twists the light into a circular form. A ray of unpolarised light passing through the linear polariser becomes polarised at 45° to the axis of the retarder. When this polarised light ray passes through the retarder, its vibration direction moves in a helical pattern. After the light ray is reflected from a specular surface, the sense of rotation of the vibration reverses. This rotation is then stopped and in return, sent through the retarder. The light ray is now linearly polarised in a plane 90° to its original polarisation plane, and is absorbed by the linearly polarised component of the circular polariser.

Circular polarisers are highly effective at eliminating sun light "wash out" caused by ambient light reflected from the display.

Retarders are made of bi-refringent material. The phase shift is dependent on the orientation of the material producing a modified polarised state. For example, to create a circular polariser the phase must be a ¼ wavelength.

3D Polariser filters

For passive 3D imaging, two images must be separated for each of the viewers' eyes, typically done by projecting images through linear polarisers, which are at perpendicular angles. The viewer wears linear polarised glasses at complimentary angles to the projected images so that each eye can only see the appropriate image.

Please contact us for more information on the supply of the linear polariser filters for this 3D application.

Photo elastic Stress Analysis

Utilizing polarised light is imperative otherwise, invisible stress in transparent material can be seen. It shows both the location and intensity of the stress. For example, in injection molding, extruded sheets and cast plastics.

Please contact us for more information on the supply of the polarisers for this stress analysis.

Polarised Sunlight readable touch screens

Sunlight readability is a big problem with resistive touch screens. The combination of badly index matched air gaps and reflective ITO coating results in a barely readable display.

The addition of a polariser and, in some applications a retarder as well, dramatically improves the contrast ratio of resistive touch screen displays. Typical applications that benefit from this technology are portable equipment, marine on deck displays, outdoor displays, avionics head down displays and in-vehicle HMI.