Vehicle Headlamp Lens Antireflection Coating for Stray Light Control
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Solution Overview
Problem
Conventional vehicle headlights obscure the visibility of the additional light-emitting areas, such as daytime running lights, when the main light is in operation due to scattered light reflections on the lens, making it difficult to recognize the trademark shape and failing to meet statutory brightness requirements.
Innovation Solution
Applying an antireflection coating to one or both surfaces of the lens to reduce scattered light reflections, allowing the additional light unit to be visible even when the main light is on, and adjusting the additional light unit's intensity to meet legal 'sign light values' without exceeding the main light's intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the additional light unit is operated at high intensity to be visible, then the visibility of the light-emitting area improves, but the stray light values exceed statutory regulations
Solution Approach 1:
The patent converts the harmful scattered light reflections into a beneficial effect by using an antireflection coating to reduce unwanted stray light while maintaining or enhancing the visibility of the additional light-emitting areas. The AR coating transforms the lens from a light-scattering element into a light-transmitting element, allowing the additional light to be visible without excessive stray light.
2Object-affected harmful factors
If the additional light unit is dimmed to meet stray light regulations, then compliance with statutory regulations improves, but the visibility of the light-emitting area deteriorates
Solution Approach 1:
The patent changes the optical parameters of the lens system by applying an antireflection coating, which modifies the light transmission and reflection characteristics. This parameter change allows the additional light to maintain sufficient visibility while operating at dimmed intensity levels that comply with stray light regulations.
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
The antireflection coating minimizes scattered radiation, enabling clear visibility of the additional light-emitting areas and ensuring compliance with legal light distribution requirements by dimming the additional light unit to maintain required signal values.
Implementation Method 1
the lens is coated with an antireflection layer (AR coating). As a result, the reflections occurring on or in the lens can be at least reduced, so that the lens generates no or significantly less scattered radiation than in the uncoated state.
Data Source
Figure 1~2
Figure 3~4
AI summary
The vehicle headlamp (100) has light unit (2) which produces main light. The lenses (3,3') are provided in the light unit, so that the light emitted by the light source is projected as main light distribution on the area ahead of vehicle. A supplementary light unit (4) for generating supplementary light distribution, is switched on during main light operation. The light-emitting portion (5) of supplementary light unit is arranged close to the lens. The light entrance surface (3a) and light-exit surface (3b) of lens are coated with respective antireflection coatings (6a,6b).