Stacked Light-Emitting Elements on Single Substrate
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Solution Overview
Problem
The high cost of LED manufacturing is largely attributed to the use of multiple substrates, which increases the overall expense without a proportional increase in lumen output, limiting the efficiency and cost-effectiveness of light-emitting devices.
Innovation Solution
A light-emitting device with multiple stacked layers on a single substrate, utilizing InxGa1-xP or InxGa1-xAs MQW structures to emit lights with different dominant wavelengths, increasing lumen output and reducing substrate usage, thereby enhancing light-emitting efficiency and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple substrates are used to increase lumen output, then the total light output increases, but the manufacturing cost increases proportionally
Solution Approach 1:
The patent combines multiple light-emitting layers on a single substrate, merging functions that traditionally required separate substrates. The first and second light-emitting layers are stacked on the same substrate, allowing multiple light sources to be integrated without proportionally increasing substrate usage or manufacturing cost.
Solution Approach 2:
The patent transitions from a planar arrangement of separate substrates to a vertical stacked configuration on a single substrate. By utilizing the vertical dimension (z-axis) with multiple light-emitting layers at different heights, the system achieves increased lumen output without expanding the horizontal substrate footprint.
2Productivity
If multiple substrates are used to achieve higher lumen output, then light production increases, but substrate usage increases without proportional efficiency gain
Solution Approach 1:
Multiple light-emitting layers are merged onto a single substrate, combining the functionality of what would traditionally require multiple separate substrates. This reduces total substrate consumption while maintaining or enhancing overall lumen output.
Solution Approach 2:
A single substrate serves multiple functions by supporting both the first light-emitting layer and the second light-emitting layer. The substrate acts as a common foundation for multiple light-generating structures, maximizing its utility and reducing the need for additional substrates.
3Productivity
If multiple light-emitting layers are stacked on a single substrate, then lumen output increases without proportional cost increase, but the device structure becomes more complex
Solution Approach 1:
The light-emitting device is segmented into distinct functional layers (first light-emitting layer, second light-emitting layer) that can be independently designed and optimized. Each layer contains its own active regions and can be tailored for specific wavelength emissions, allowing modular complexity management.
Solution Approach 2:
The patent resolves structural complexity by organizing multiple light-emitting layers in the vertical dimension rather than requiring complex lateral arrangements. This vertical stacking approach simplifies the overall device architecture compared to planar configurations while still achieving enhanced lumen output.
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 device achieves improved light-emitting efficiency and reduced manufacturing costs by using a single substrate for multiple light-emitting layers, increasing lumen output per dollar spent and improving light-emitting efficiency through increased current spread and series resistance.
Implementation Method 1
When imposing a certain level of forward voltage to the p-n junction, holes from the p-type semiconductor layer and electrons from the n-type semiconductor layer are combined to release light
Data Source
AI summary
A light-emitting device includes a carrier; a first light-emitting element formed on a first portion of the carrier, including: a first MQW structure configured to emit a first light with a first dominant wavelength; a second MQW structure configured to emit a second light with a second dominant wavelength on the first MQW structure; wherein the first MQW structure and the second MQW structure both comprise InxGa1-xP or InxGa1-xAs, wherein 0<x<1; and a second light-emitting element, formed on a second portion on of the carrier, including a light-emitting stacked layer configured to emit a third light with a third dominant wavelength, wherein the third light is blue, wherein a difference between the first dominant wavelength and the second dominant wavelength is 5 nm to 30 nm.