Multi-LED Wavelength-Converting Assembly for Uniform Luminance
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Solution Overview
Problem
Prior semiconductor light-emitting apparatuses with multiple elements suffer from uneven luminance intensities and color unevenness due to fluctuations in the heights and slopes of semiconductor light-emitting elements, leading to inconsistent heat resistances and adhesive layer thicknesses.
Innovation Solution
The solution involves using a conductive eutectic layer and thermally-pressuring process to achieve self-alignment of semiconductor elements, ensuring uniform adhesive layer thicknesses and consistent heat resistances by minimizing the circumferential surface of eutectic material layers, thereby maintaining uniform heights and reducing standard deviations in adhesive and eutectic layer thicknesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple semiconductor light-emitting elements are mounted on the substrate via eutectic layers, then the luminance intensity increases, but the heights of the upper surfaces of the semiconductor light-emitting elements greatly fluctuate due to fluctuations in heights and slopes of the elements
Solution Approach 1:
The patent introduces an intermediate layer between the semiconductor light-emitting elements and the wavelength-converting plate, dividing the mounting structure into separate functional layers. This intermediate layer compensates for height variations of individual elements, allowing each element to be mounted independently while maintaining uniform upper surfaces for the wavelength-converting plate.
Solution Approach 2:
The patent uses a transparent adhesive layer as an intermediary substance between the semiconductor elements and the wavelength-converting plate. This adhesive layer acts as a mediator that fills the gaps caused by height variations, ensuring uniform contact and consistent optical properties across all elements.
2Illumination intensity
If the wavelength-converting plate is adhered to each semiconductor light-emitting element via transparent adhesive layers, then the light conversion is achieved, but the heat resistances between the wavelength-converting plate and each semiconductor light-emitting element greatly fluctuate
Solution Approach 1:
The patent separates the mounting function (performed by eutectic layers) from the optical coupling function (performed by transparent adhesive layers). This segmentation allows the adhesive layers to be optimized for optical properties while the eutectic layers handle mechanical bonding, resulting in uniform heat resistance and improved reliability.
3Ease of manufacture
If the transparent adhesive layers have large standard deviation in thickness, then the manufacturing process is simpler, but the luminance intensities of the semiconductor light-emitting elements are not uniform and color unevenness occurs
Solution Approach 1:
The patent divides the adhesive system into two separate layers: eutectic layers for mechanical bonding and transparent adhesive layers for optical coupling. This segmentation allows each layer to be optimized independently, with the transparent adhesive layers providing uniform thickness for consistent luminance and color across all elements.
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 approach results in uniform luminance intensities and color distribution across semiconductor light-emitting elements, enhancing reliability and performance by ensuring consistent heat dissipation and alignment.
Implementation Method 1
a conductive eutectic layer and thermally-pressuring process to achieve self-alignment of semiconductor elements
Implementation Method 2
thermally-pressuring process to achieve self-alignment of semiconductor elements
Implementation Method 3
The wavelength-converting plate includes phosphor for converting a part of light emitted by the semiconductor light-emitting element into wavelength-converted light with a longer wave length
Implementation Method 4
a wave length-converting plate adhered to the upper surface of the semiconductor light-emitting element via a transparent adhesive layer
Implementation Method 5
a semiconductor light-emitting apparatus such as a white-light light-emitting diode (LED) apparatus
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 2D~2F
AI summary
A semiconductor light-emitting apparatus includes: a wiring substrate (1); multiple semiconductor light-emitting elements (2-1, 2-2, 2-3, 2-4) mounted via multiple eutectic layers (3-1, 3-2, 3-3, 3-4), respectively, on the wiring substrate (1); and a wavelength-converting plate (4) mounted via multiple transparent adhesive layers (5-1, 5-2, 5-3, 5-4) on upper surfaces of the semiconductor light-emitting elements (2-1, 2-2, 2-3, 2-4), respectively. A standard deviation (sigma 1) of thicknesses of the transparent adhesive layers (5-1, 5-2, 5-3, 5-4) is smaller than a standard deviation (sigma 2) of thicknesses of the eutectic layers (3-1, 3-2, 3-3, 3-4).