While indoor LED lighting and LCD displays are on opposite sides of the spectrum, they often share a common problem, light leaking. Light leaking may not be an official terminology, but it adequately describes the problem of light emitting from an enclosure or housing where it is not intended.
Ambient lighting fixtures, such as fluorescent, LED, or incandescent have areas or joints where the designer wants to contain the light – or prevent a light leak. This can be addressed with lightweight foam materials to create a light leak gasket. Most lighting fixtures require components, including foam, to be UL listed which may include UL 1570 (fluorescent), UL 1571 (incandescent), UL 1572 (HID) and UL 94 (flame rating). Stockwell Elastomerics inventories HT-870, HT-800, HT-820silicone foams which are UL listed for the above lighting fixture specifications. These materials, as well as BF-1000, BF-2000 and F-12 low density silicone foams are UL 94 listed and most meet UL 94V-0. Additionally, silicone foams are UV and ozone resistant and withstand the effects of outdoor conditions and electrical enclosure environments for many years.
Handheld electronics also use gaskets to prevent light leaking from the display or illuminated buttons. The typical material for display gaskets is Poron microcellular urethane foam. Industrial grade Poron foams are available in a wide range of thicknesses and firmnesses that help designers make a good fit in tight electronic devices. 3M 9795B is a unique double coated adhesive that uses a black PET layer as opposed to the traditional transparent PET to help mitigate light piping thru the PET layer. Stockwell Elastomerics offers 3M 9795B and 3M 467 (2 mil thick) as suggested adhesive options for light leak gaskets.