Light-Emitting Device Wavelength Conversion Layer Geometry
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Solution Overview
Problem
Conventional light-emitting devices with multiple elements face challenges in maintaining stable operation and high light extraction efficiency, especially when driven with large currents or used in varying environments, such as vehicular lamps, due to issues with wavelength conversion layer thickness, heat dissipation, and light intensity uniformity.
Innovation Solution
A light-emitting device configuration featuring a substrate with multiple light-emitting elements, wavelength conversion layers with specific side surface shapes and adhesive layers, and a light-transmitting plate covered by a reflective resin, where the wavelength conversion layers have inclined side surfaces and uniform thickness, enhancing light extraction and heat dissipation, and the adhesive fills gaps between layers for improved uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a plurality of light-emitting elements are arranged closely to increase light output, then light extraction efficiency improves, but heat dissipation becomes insufficient and operation stability deteriorates
Solution Approach 1:
The invention divides the wavelength conversion layer into multiple separate layers, each corresponding to individual light-emitting elements. This segmentation allows each layer to be independently optimized for thickness and composition, improving heat dissipation from each element while maintaining high light extraction efficiency. The adhesive layers between wavelength conversion layers create thermal pathways that prevent heat accumulation.
2Productivity
If wavelength conversion layer thickness is increased to improve light conversion, then light extraction efficiency improves, but heat dissipation deteriorates and operation stability decreases
Solution Approach 1:
The invention applies different thicknesses to different wavelength conversion layers based on local requirements. Each wavelength conversion layer can have optimized thickness tailored to its specific light-emitting element's characteristics and thermal conditions. This local optimization allows maximum light conversion efficiency while preventing excessive heat accumulation in any single region.
3Area of stationary object
If light-emitting elements are arranged in a compact configuration to reduce device size, then device compactness improves, but light intensity uniformity deteriorates
Solution Approach 1:
Each wavelength conversion layer is independently configured with specific thickness and material composition to compensate for variations in light intensity across the device. This local quality adjustment ensures uniform light output even when light-emitting elements are closely arranged, as each layer can be optimized to balance the overall illumination distribution.
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 configuration achieves high operation stability and light extraction efficiency, suppressing color and intensity unevenness, and allowing for stable heat dissipation, even under high current or prolonged use, making it suitable for vehicular applications.
Implementation Method 1
a plurality of wavelength conversion layers 30 each disposed on each of the plurality of light-emitting elements 20
Implementation Method 2
a reflective resin 14 covering side surfaces of each of the plurality of light-emitting elements 20, side surfaces forming outer edge portions of the plurality of wavelength conversion layers 30, and side surfaces of the light-transmitting plate 40
Data Source
AI summary
A light-emitting device having light-emitting elements with high operation stability and light extraction efficiency is provided. The light-emitting device includes: a substrate; light-emitting elements aligned and arranged on the substrate in an arrangement direction; wavelength conversion layers each disposed on each of the light-emitting elements with a light-transmitting adhesive interposed therebetween, each of the wavelength conversion layers having an upper surface smaller than a bottom surface, and a side surface shape in which a length in a lateral direction parallel to the bottom surface and perpendicular to the arrangement direction decreases from the bottom surface toward the upper surface; a light-transmitting plate disposed over the wavelength conversion layers; and a reflective resin covering side surfaces of the light-emitting elements, the wavelength conversion layers, and the light-transmitting plate. A side surface of the wavelength conversion layer facing to another adjacent wavelength conversion layer extends in a direction perpendicular to the substrate.