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Drawing from previous studies published in SAE, a software program describes physical progress of water intrusion into or released from a lamp assembly. This program, based on test data, calculates condensation quantity and clearing time. It calculates moisture exchange between a lamp assembly and ambient, considering the moisture contained in the air inside of the lamp and moisture stored on the wall surface or in the materials. This program is applicable to different scenarios, such as initial humidity conditions of a lamp assembly, lamp size, type, venting type and test performance specifications. The significance of the program application in guiding test performance will also be addressed.

The effect of water vapor transfer from plastic materials commonly used in automotive lighting assemblies can be experimentally measured. This is accomplished by isolating this phenomenon from other mechanisms effecting water vapor concentration in the lamp. Quantifying this effect helps to address design considerations for liquid water and water vapor egress in the lighting assembly. The relevance of the current moisture clearing type test required in the industry is discussed in light of the empirical results for this effect.

Currently, there is still no standardized method to measure LED flux in automotive lighting. Usually, LED manufacturers provide a lumen range (or bin) for a given type of LED. However, with the increased usage of high-flux LEDs, the need for an absolute lumen value is becoming important for optical design of automotive lamps. The knowledge of an LED lumen value is necessary for more precise lamp designs. Three different types of measurements for LED flux were compared. These three measurement methods are: 1). 2π flux integrating sphere; 2). 4π flux integrating sphere; and 3). Goniometer. In this paper, we will discuss the results from these three methods, and conclude with recommendations on the preferred methods and parameters critical for accurate LED flux measurements.

Certain conditions promote water vapor to condense on available surfaces within an automotive lighting assembly. Certain surfaces are more susceptible to water condensation than others. This is due partially to temperature gradients in the lamp and possibly water vapor concentration gradients. This study demonstrates that humidity gradients exist in an automotive lamp. How humidity gradients affect the likelihood of surface condensation for a particular interior surface of a lamp will also be addressed.