Vehicle Headlamp Fluorescence Control via Light Shielding
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Solution Overview
Problem
Existing light emitting devices for vehicle headlamps do not effectively increase the use efficiency of fluorescence, leading to inefficient energy consumption and reduced light-emitting duration due to uncontrolled lateral fluorescence emission.
Innovation Solution
A light emitting device configuration with an excitation light source, a light emitting section that emits fluorescence in a Lambertian distribution, and a light projecting section with a larger main light emitting surface area than the side surface area, where the light projecting section projects fluorescence along a predetermined direction, reducing lateral emission and enhancing control over the fluorescence path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional light emitting device uses a fluorescent material to convert excitation light to white light, then illumination is provided, but the use efficiency of fluorescence is low due to uncontrolled lateral emission
Solution Approach 1:
The patent extracts and removes the harmful lateral fluorescence emission from the system by using a light-shielding member positioned adjacent to the light emitting section. This member specifically blocks fluorescence emitted in lateral directions (perpendicular to the light projection direction), preventing this uncontrolled emission from reaching the projection lens and being wasted, thereby improving fluorescence use efficiency.
Solution Approach 2:
The light-shielding member acts as an intermediary element between the light emitting section and the projection lens. It selectively intercepts lateral fluorescence emission and redirects or blocks it, while allowing the desired forward-emitted fluorescence to pass through to the lens. This mediator enables control over the fluorescence distribution without affecting the primary illumination function.
2Ease of operation
If the light emitting section emits fluorescence in all directions including lateral directions, then total fluorescence output is maximized, but control over the fluorescence path is reduced
Solution Approach 1:
The light-shielding member extracts and removes lateral fluorescence emission from the optical path, separating it from the useful forward-directed fluorescence. By positioning the shielding member adjacent to the light emitting section, it specifically targets and blocks lateral emission angles while leaving the forward emission path intact, thereby improving control over which fluorescence reaches the projection lens.
Solution Approach 2:
The light-shielding member serves as an intermediary that selectively interacts with fluorescence based on its emission direction. It mediates between the isotropic fluorescence emission from the light emitting section and the directional requirements of the projection lens, allowing controlled transmission of useful light while blocking harmful lateral emission.
3Device complexity
If no light-shielding member is provided, then the device structure is simple, but the percentage of controllable fluorescence is reduced
Solution Approach 1:
The light-shielding member is strategically positioned to extract only the harmful lateral fluorescence component from the total emission, rather than blocking all fluorescence or requiring complex optical systems. This selective extraction achieves significant improvement in controllable fluorescence percentage with minimal structural addition.
Solution Approach 2:
The light-shielding member introduces a simple intermediary element that provides directional control functionality without requiring complex optical components. Its placement adjacent to the light emitting section creates an effective barrier against lateral emission while maintaining overall structural simplicity and ease of integration.
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
This configuration increases the percentage of fluorescence that can be controlled, reducing uncontrolled lateral emission and enhancing the use efficiency of fluorescence, thereby improving energy efficiency and extending the light-emitting duration of the device.
Implementation Method 1
a light emitting section for emitting fluorescence upon receiving the excitation light emitted from the excitation light source
Data Source
AI summary
A headlamp of an embodiment of this invention includes a laser element, a light emitting section, and a parabolic mirror. A part of the parabolic mirror is provided so as to face an upper surface of the light emitting section, which upper surface has a larger area than that of a side surface of the light emitting section. The light emitting section emits fluorescence in such a manner that distribution of the fluorescence corresponds to the Lambertian distribution.