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

Com-Corp’s Bulb Shield Automotive headlamp requires light shielding Bulb shield component Metal stamping Decorative nickel chrome plating New 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 Applied to shield interior surface to prevent unwanted reflections With paint Without paint

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

Deleterious effects of elevated temperature Oxidation of Ni-Cr at 315° Celsius Yellow oxide reflects in lamp EDS graph of discolored area

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

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

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

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

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

Reflectivity profiles Normal Paint Designed for low reflectance for headlamp photometry New coating Pigmented to absorb visible radiation (490-720nm) Highly reflective in near infrared

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

Statistical analysis of results ANOVA – normal distribution ANOVA Per Paint Source of Variation F P-value F critical Between Groups 24.19592443 3.43E-18 2.016601

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

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

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

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

Contact Information Isatec Tooling and Engineering Dr. Steven Sheng ssheng@ccioh.com 216-265-9449 Illume LLC Michael Strazzanti mstrazz@illumeco.com 216-299-3567