Partially Transmissive Shutter Bump for Headlamp Glare Reduction
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Solution Overview
Problem
Traditional shutter designs in projector headlamps are 'all-or-nothing,' unable to reduce light in specified areas while allowing some illumination, failing to meet newer photometric output requirements for sharper gradient cutoffs and reduced glare, as they are made of heavy sheet metal to withstand heat from halogen or HID light sources.
Innovation Solution
A projector apparatus with a shutter that can move between positions to selectively obscure or attenuate light, using a plastics material for the shutter that allows differential light transmissive regions, enabling adjustment of luminosity in specific areas below the horizontal axis while maintaining compliance with regulatory limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional sheet metal shutters are used to block light in specified areas, then the shutter can withstand the heat of halogen or HID light sources, but the shutter cannot reduce light in specified areas while still allowing some light to illuminate the area
Solution Approach 1:
The shutter is constructed with regions of different light transmissivity, including opaque regions for blocking light and translucent regions for attenuating light. This local differentiation allows different portions of the shutter to perform different optical functions simultaneously, enabling precise control over light distribution patterns.
Solution Approach 2:
The shutter employs composite construction combining opaque and translucent materials in a single component. This allows the shutter to function as both a complete light blocker and a light attenuator within the same device, providing versatile light control capabilities.
2Temperature
If sheet metal is used for the shutter to withstand heat, then the shutter can endure high temperatures from halogen or HID light sources, but the shutter becomes heavy
Solution Approach 1:
The invention transitions from metal to plastics material, fundamentally changing the thermal and mechanical parameters of the shutter. The plastics material is selected to withstand the operational temperature range while providing the necessary structural integrity and optical properties.
Solution Approach 2:
The plastics material shutter replaces expensive, heavy metal shutters with a lighter, more cost-effective alternative that meets the functional requirements for heat resistance and light control in automotive headlamp applications.
3Device complexity
If traditional all-or-nothing shutter designs are used, then the shutter structure is simple, but the shutter cannot meet newer photometric output requirements for sharper gradient cutoffs and reduced glare
Solution Approach 1:
The shutter incorporates regions with different light transmissivity properties (opaque and translucent) to create precise light distribution patterns. This allows the simple shutter structure to achieve complex photometric requirements through material property differentiation rather than structural complexity.
Solution Approach 2:
The invention uses variations in light transmissivity (analogous to color/optical property changes) across different regions of the shutter to control light distribution. The translucent regions allow partial light transmission to create gradient cutoffs and control glare while maintaining overall pattern integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the adjustment of luminosity in specific areas to meet stricter photometric requirements, reducing glare and improving low beam performance without exceeding maximum permitted intensity, thus addressing the limitations of traditional shutter designs.
Implementation Method 1
a shutter bump configured to attenuate a amount of visible light emitted from the projector lens in a predefined area of the first light distribution pattern
Data Source
AI summary
A projection headlamp (12) has a reflector (28) reflecting light emitted from a light engine (20); a projector lens (30) projecting reflected light from the reflector (28); and a shutter (22) disposed between light engine (20) and projector lens (30), the shutter (22) having an upper edge (44) defining a cut-off to generate a low beam pattern by obscuring a portion of the projector lens (30) from the reflected light and to selectively emit the reflected light through the projector lens (30) in a low-beam light distribution pattern. The shutter (22) further includes a partially light-transmissive shutter bump (56) extending above the upper edge (44) which attenuates light emitted from the projector lens (30) in a predefined area of the low-beam pattern. Light intensity at the 0.86D, 3.5L NHTSA test point (112) is attenuated to below maximum photometric intensity (12,000 candela), avoiding glare.