Infrared Reflective Bulb Shield Com-Corp Industries Tier 1-2 automotive metal stamping and manufacturing Isatec Technical Center Captive tooling, engineering and process design Illume Affiliated advanced research and development company

Introduction Illume researches solution Isatec designs manufacturing process Com-Corp has a problem

Com-Corp’s Bulb Shield Automotive headlamp requires light shielding Automotive headlamp requires light shielding Bulb shield component Bulb shield component Metal stampingMetal stamping Decorative nickel chrome platingDecorative nickel chrome plating New light bulbs and lamp designs were causing bulb shield to overheatNew light bulbs and lamp designs were causing bulb shield to overheat

Bulb shield orientation Figure 1 Cross section of a headlamp with bulb shield (2) installed in front of bulb (1) and reflector (3)

Bulb shield interior coating High temperature black paint High temperature black paint Applied to shield interior surface to prevent unwanted reflectionsApplied to shield interior surface to prevent unwanted reflections With paint Without paint

Bulb shield temperature Mechanical Actions Mechanical Actions Proximity to bulbProximity to bulb Lack of air flowLack of air flow Thermodynamic Actions Thermodynamic Actions Electromagnetic radiation absorbed by the shieldElectromagnetic radiation absorbed by the shield  Interior coating reflectivity  Exterior coating low emissivity

Deleterious effects of elevated temperature Oxidation of Ni-Cr at 315° Celsius Oxidation of Ni-Cr at 315° Celsius Yellow oxide reflects in lampYellow oxide reflects in lamp EDS graph of discolored area Video will turn black while downloading. May take several minutes depending on connection speed

Deleterious effects of elevated temperature Bulb shield required to pass SAE vibration testBulb shield required to pass SAE vibration test Tensile strength of steel reduced at elevated temperaturesTensile strength of steel reduced at elevated temperatures

Previous research efforts to reduce shield temperature Sah and Park – Shape and Orientation Sah and Park – Shape and Orientation Geometry of the bulb shield – air flowGeometry of the bulb shield – air flow Geometry of the reflectorGeometry of the reflector Location of shield with respect to the bulbLocation of shield with respect to the bulb Reduced bulb shield temperature by 15-20%Reduced bulb shield temperature by 15-20%

Economic impact of those solutions Alter geometry of the bulb shieldAlter geometry of the bulb shield Changes to existing tooling Changes to existing tooling Mechanical integrity of the shield Mechanical integrity of the shield Geometry of the reflectorGeometry of the reflector Changes to existing tooling Changes to existing tooling Location of shield with respect to the bulbLocation of shield with respect to the bulb Changes to one or both components Changes to one or both components

Paint removal as a solution No Paint No Paint Highly reflective nickel-Chrome surfaceHighly reflective nickel-Chrome surface Affects photometry of lampAffects photometry of lamp Metallic Flake Paint Metallic Flake Paint Increase in reflectivity – some preferential IRIncrease in reflectivity – some preferential IR

Research new interior coating solution Visible wavelengths must be absorbedVisible wavelengths must be absorbed Infrared should be reflectedInfrared should be reflected Bulb output Ideal coating

Reflectivity profiles Normal Paint Normal Paint Designed for low reflectance for headlamp photometryDesigned for low reflectance for headlamp photometry New coating New coating Pigmented to absorb visible radiation ( nm)Pigmented to absorb visible radiation ( nm) Highly reflective in near infraredHighly reflective in near infrared

Comparison of coating based solutions Headlamp used as test environment Headlamp used as test environment Type K thermocouple Type K thermocouple Computer data collection interface Computer data collection interface Sample sets randomized Sample sets randomized

Statistical analysis of results ANOVA – normal distribution ANOVA – normal distribution ANOVA Per Paint Source of Variation FP-value F critical Between Groups E

Performance Only un-coated shield performed better Only un-coated shield performed better IR reflective sample 2 was best performer IR reflective sample 2 was best performer

Comparison to metallic flake coating Both show statistically significant reductions in temperature Both show statistically significant reductions in temperature IR reflective was 5.7% cooler than metallic flake IR reflective was 5.7% cooler than metallic flake

Shield Proximity Factor Eliminate variation in shield geometry as variable Eliminate variation in shield geometry as variable No statistical significance in shield proximity to bulb between sample setsNo statistical significance in shield proximity to bulb between sample sets IR 2 samples were actually closest to bulbIR 2 samples were actually closest to bulb

Conclusion Infrared reflective bulb shield Infrared reflective bulb shield Comparable reduction in temperature to altering lamp designComparable reduction in temperature to altering lamp design No special handlingNo special handling No increase in costNo increase in cost Maintain low visible reflectanceMaintain low visible reflectance U.S. and foreign patents pendingU.S. and foreign patents pending

Contact Information Isatec Tooling and Engineering Dr. Steven Sheng Illume LLC Michael Strazzanti