LED Wavelength Conversion Structure for Uniform Light Extraction
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Solution Overview
Problem
Existing semiconductor light emitting devices face issues with light efficiency due to light loss and total reflection, as well as color uniformity problems in emitted light.
Innovation Solution
The semiconductor light emitting device incorporates an LED chip with a first and second wavelength conversion layer and a reflective resin portion, where the wavelength conversion layers are strategically positioned on the upper and side surfaces of the LED chip to minimize light loss and enhance color uniformity by adjusting the refractive indices and angles of light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If wavelength conversion layers are added to convert light wavelength, then color uniformity is improved, but light loss increases due to absorption in the conversion layers
Solution Approach 1:
The patent extends the wavelength conversion layers from a single plane to multiple dimensions by adding layers on both the upper surface and side surfaces of the LED chip. This multi-dimensional arrangement distributes the light conversion function across different spatial locations, improving color uniformity while managing light loss through optimized path lengths in each layer.
Solution Approach 2:
The patent applies different wavelength conversion layers with specific properties to different locations: the first wavelength conversion layer is on the upper surface with specific thickness and refractive index, while the second wavelength conversion layer is on the side surface with different thickness and refractive index. This local differentiation optimizes color uniformity while minimizing absorption losses in each region.
2Ease of manufacture
If conventional packaging structure is used, then manufacturing is simple, but light efficiency deteriorates due to total reflection and light loss
Solution Approach 1:
The patent modifies key optical parameters of the packaging structure: the refractive indices of the wavelength conversion layers are specifically controlled (first layer: 1.4-1.6, second layer: 1.3-1.5), and the side surface is designed with a specific inclination angle (30-60 degrees). These parameter changes reduce total internal reflection and improve light extraction efficiency while maintaining manufacturability.
Solution Approach 2:
The patent introduces a curved inclined surface on the side of the LED chip package instead of a flat surface. This curvature design helps to redirect light paths, reduce total internal reflection at interfaces, and improve overall light extraction efficiency without significantly complicating the manufacturing process.
3Loss of energy
If light extraction efficiency is improved by adjusting refractive indices, then light loss decreases, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies refractive index ranges rather than exact values (first layer: 1.4-1.6, second layer: 1.3-1.5), allowing for manufacturing tolerances. This partial specification approach achieves the desired light extraction efficiency improvement while accommodating normal variations in material properties during manufacturing, thus balancing performance with manufacturability.
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 improves light extraction efficiency and achieves better color uniformity by reducing total reflection and increasing the directivity angle of emitted light, resulting in a more consistent color temperature across the light emitting surface.
Implementation Method 1
a first wavelength conversion layer having a first region provided on the upper surface of the LED chip and a second region which extends past the side surface of the LED chip; a second wavelength conversion layer having a first surface contacting the side surface of the LED chip
Implementation Method 2
minimizing light loss to improve light efficiency and improving color uniformity of a light emitting surface
Implementation Method 3
a reflective resin portion provided on the lower surface of the LED chip and the fourth surface, and defining openings that expose at least a portion of each of the first conductive bump and the second conductive bump
Data Source
AI summary
A semiconductor light emitting device is provided. The device includes: an LED chip having a lower surface, an upper surface, and a side surface between the upper surface and the lower surface; first and second conductive bumps disposed on first and second conductive bumps provided on the lower surface; a first wavelength conversion layer having a first region provided on the upper surface of the LED chip and a second region which extends past the side surface of the LED chip; a second wavelength conversion layer having a first surface contacting the side surface of the LED chip, a second surface, a third surface connecting the first surface and the second surface, and contacting the second region, and a fourth surface located opposite to the third surface and inclined; and a reflective resin portion provided on the lower surface of the LED chip and the fourth surface.