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Proceedings Paper

A characterization of UV effects on optical silicones used in opto-electronic devices and new developments in resistant materials
Author(s): Bill Riegler; Randall Elgin; Rob Thomaier
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Paper Abstract

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.

Paper Details

Date Published: 9 February 2007
PDF: 11 pages
Proc. SPIE 6478, Photonics Packaging, Integration, and Interconnects VII, 64780F (9 February 2007); doi: 10.1117/12.699166
Show Author Affiliations
Bill Riegler, NuSil Technology LLC (United States)
Randall Elgin, NuSil Technology LLC (United States)
Rob Thomaier, NuSil Technology LLC (United States)

Published in SPIE Proceedings Vol. 6478:
Photonics Packaging, Integration, and Interconnects VII
Allen M. Earman; Ray T. Chen, Editor(s)

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