Evaluation of Fabrication Errors on the Performance of Injection Molded Light Pipes (Waveguides) 2001-01-0863
This paper examines the consequences of fabrication effects on the performance of injection molded plastic light pipes for distributive automotive lighting. It discusses the magnitude of these effects on propagating and output light. Molding errors, such as sinks, voids, flow lines, knit lines, and warpage, will be examined through computer modeling and measurement of sample distributive lighting systems.
Two example light pipe systems will be presented, an instrument cluster pointer system and a regional distributive interior lighting system. For the pointer system, computer modeling results, such as total light output and output exitance distributions will be presented. Modeling results will be presented for both an error free system and system that include the aforementioned molding errors. These results will be compared to determine the output light loss and redistribution. For the regional interior lighting system, total output and exitance measurements of fabricated light pipe systems will be presented for comparison and to illustrate the effects of errors.
Since it is impossible or impractical to eliminate all injection molding fabrication errors from manufactured light pipe systems, this paper will conclude with a discussion of the circumstances under which individual errors should be diminished or eliminated.