LED Array Design for Uniform Automotive Headlamp Illumination
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Solution Overview
Problem
Existing LED arrays for automotive headlamps face challenges in achieving uniform brightness and color distribution due to large intervals between LED elements, leading to nonuniform light emission when using phosphor or fluorescence powder-containing sealing resins.
Innovation Solution
The LED array design reduces the distance between adjacent LED chips to 80 μm or less by forming interconnection wirings on the substrate's peripheral regions, allowing for improved light uniformity and increased utilization efficiency of epitaxial layers, thereby reducing nonuniform brightness and color distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If LED elements are arranged horizontally with sufficient spacing for separate assembly, then ease of manufacture is improved, but brightness uniformity and chromaticity uniformity deteriorate due to large intervals between elements
Solution Approach 1:
The patent merges the LED element fabrication process with the array assembly process by forming multiple LED elements directly on a single substrate in an array configuration. This eliminates the need for separate assembly of individually fabricated LED elements, reducing the interval between elements to minimal spacing while maintaining manufacturing efficiency. The merging of processes allows achieving both ease of manufacture and brightness uniformity simultaneously.
2Illumination intensity
If the interval between adjacent LED elements is reduced to improve brightness uniformity, then brightness distribution uniformity is improved, but manufacturing complexity increases due to tighter spacing requirements
Solution Approach 1:
The patent segments the substrate into multiple regions, each dedicated to forming a specific LED element. This segmentation approach allows systematic arrangement of multiple LED elements in an array with minimal spacing while maintaining clear fabrication processes. By dividing the substrate into discrete element regions, the patent reduces manufacturing complexity despite tight spacing requirements, as each segment can be processed independently through standardized fabrication steps.
3Adaptability or versatility
If separate LED elements are assembled on a support substrate, then adaptability in design is improved, but brightness uniformity and chromaticity uniformity deteriorate due to required spacing intervals
Solution Approach 1:
The patent creates a universal substrate structure that can accommodate various LED element configurations and designs. The standardized array format with minimal spacing requirements serves multiple functions: achieving brightness uniformity, maintaining chromaticity uniformity, and providing design flexibility. This universal approach allows different LED element designs to be implemented on the same substrate type, enhancing adaptability while ensuring uniform light emission characteristics.
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 design enhances the uniformity of light brightness and color distribution in LED arrays, improving the efficiency and cost-effectiveness of LED arrays for automotive applications by minimizing non-light emitting regions and optimizing the use of epitaxial layers.
Implementation Method 1
a plurality of LED chips disposed on the substrate in an intermediate region in the widthwise direction, and aligned along the lengthwise direction
Data Source
AI summary
A light emitting device includes a substrate elongated in a lengthwise direction; a plurality of LED chips disposed on the substrate in an intermediate region in widthwise direction, and aligned along the lengthwise direction at a distance of 80 μm or less; and interconnection wirings formed on regions outside the intermediate region in the widthwise direction; wherein each of the LED chips has a p-side electrode disposed on the substrate, a p-type semiconductor layer disposed on the p-side electrode, an active layer formed on the p-type semiconductor layer, and an n-type semiconductor layer formed on the active layer, and has a region in which the n-type semiconductor layer, the active layer, and the p-type semiconductor layer are patterned, and an n-side electrode formed selectively on a surface of the n-type semiconductor layer and connected to the p-side electrode of an adjacent LED chip through the interconnection wiring.