Specially formulated diffusion filter materials have successfully optimized the legibility of miniature display viewing areas, providing brighter and more enhanced images for a variety of applications ranging from rugged military and automotive electronics to cell phones, notebook computers, and video cameras. Industrial instruments and avionics can also benefit from this technology.

Optical Quality, Acrylic Diffusion Filter Materials enhance miniature color displays used in rugged vehicle systems and military combatant ground systems, such as this one used by the U.S. Army's Force XXI Battle Command Brigade. Image courtesy of TRW, Inc.

Diffusion filters work by efficiently scattering light from a direct backlit light to the display surface. Strong light is diffused so that light particles scatter uniformly, filling the entire viewing area of the display. As a result, images are much sharper and easier to read.

This optical quality acrylic diffusion filter material, Clarex®, provides the flexibility, size, thickness (ranging from 0.012"to 0.080"), and transmissive properties required depending on the space available between the display surface and the bulb. The diffusers are pure white with a color temperature of 6750K that eliminates color shift.

Manufactured using proprietary technology, the diffusers are created using a combination of embossed surfaces (matte finish on both sides) and proprietary light scattering additives, which are added to the material during the casting process. The amount of additive changes the transmissive properties by altering the amount of diffussed light (the scattering of light that eliminates hot spots or dark spots) and through light (the amount of light allowed to pass through the sheet). Conventional diffusors simply provide transmission properties using either the embossing or additive methods, but not both. Combining these methods allows for the fabrication of sheets with varying thicknesses and light transmission properties ranging from 45 to 93 percent. Cast acrylic is considered a high impact, weatherable material ideally suited for ruggedized and portable equipment.

This work was done by Mark Bogin for Astra Products, Inc.For more information on diffusion materials, e-mail mbogin@astraproducts. com, or contact Astra Products, Inc. at P.O. Box 479, Baldwin, NY 11510, (631) 242-1612, or fax (631) 242-1620. Visit the company on-line at www.astraproducts.com.


Photonics Tech Briefs Magazine

This article first appeared in the January, 2004 issue of Photonics Tech Briefs Magazine.

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