Opto-electronic devices such as LEDs, optical sensors, LCDs and color filters have the need for optically
transparent encapsulants or adhesives. Maintaining the highest transmission possible of the
encapsulant/adhesive throughout the life of the device is a critical criteria for the device designer. Silicones
as encapsulants/adhesives in opto-electronic devices have been used throughout the last decade1, 2. The high
light flux and associated heat proved too much for the traditional epoxies. Data confirms silicone
encapsulants/adhesives provide longer optical transmission life than epoxy encapsulants3.
Almost all optical devices have some interaction with UV wavelengths. Manufacturers of Blue LEDs with
wavelengths near 405nm, and other LEDs that emit wavelengths deeper into the UV (365-399nm), have
concerns about the effects of this radiation on the light transmission of the encapsulant over time. LCD and
sensor devices may have UV radiation from the sun to contend with. This paper looks at many different
encapsulants/adhesives, silicone, epoxy and acrylate, for their change in optical transmission due to a 680-68000J/cm2 dose of radiation with the following spectral output: 34% in the UVA (320-399nm), 17% in the
UVB (280-319nm), and 49% concentrated at 405nm and 450nm. All samples were prepped and exposed
the same way so that comparisons between the samples would be meaningful. Results show that silicones
perform better than acrylates, which perform better than epoxies, and not all silicones perform equally.
Data will be provided of the best performing materials and a discussion of future work given the
understanding of the chemistry.