Patent ID: 10408406

Abstract:
A partially coated lamp capsule (212) for a projection headlamp (12) has filament (224) in capsule envelope (220) having light-transmissive coating (60) extending from capsule upper region (225) towards filament distal end (227) to an axial location in a region defined between about 0.098 inch (2.5 mm) above filament distal end (227) and about 0.098 inch below filament distal end (227), the capsule envelope (220) being uncoated on an undistorted portion of capsule envelope (220) below filament proximal end (229). Lamp capsule (212) is useful in projection headlamp (12) having a reflector (28) whose central heel (37) forms the hot spot and casts light through projector lens (30) to generate low and/or high beam patterns. Present lamp capsules (212) give increased photometric intensity over conventional lamps in low beam at critical driver's lane (0.6D, 1.3R) and (0.86D, V) test points, and in high beam at the critical (H,V) test point.