Monolithic Di-Chromatic LED Structure for Stable Color Coordinates
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Solution Overview
Problem
Current light emitting diode (LED) technologies face challenges in implementing various colors without the use of phosphors, which complicates manufacturing, leads to efficiency reduction, and increases size, and results in unstable color coordinates due to changes in current densities.
Innovation Solution
A monolithic di-chromic device is developed, comprising a first and second conductivity type semiconductor region with a color region that includes a first and second color portion, emitting blue and green or yellow light, respectively, with a tunnel barrier layer and bridge region to stabilize color coordinates across varying current densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If phosphors are used with light emitting diodes to implement various colors, then color implementation is achieved, but manufacturing complexity increases, efficiency reduces, and device size increases
Solution Approach 1:
The patent combines multiple color-emitting regions (first color portion emitting blue light, second color portion emitting green or yellow light) within a single monolithic semiconductor device structure. This integration eliminates the need for separate LEDs and phosphor materials, thereby reducing manufacturing complexity while maintaining color implementation capability.
Solution Approach 2:
The invention extracts and eliminates the phosphor component from the traditional LED color implementation system. By using direct electroluminescence from multiple quantum well regions with different band gaps, the patent removes phosphor-related manufacturing complexities, efficiency losses, and size increases while still achieving various colors.
2Adaptability or versatility
If multiple light emitting diodes with different peak wavelengths are arranged adjacent to one another to implement various colors, then color implementation is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple color-emitting functions into a single monolithic semiconductor device with multiple quantum well regions. Instead of manufacturing and assembling separate LEDs with different peak wavelengths, the invention achieves multi-color emission from one integrated structure, significantly simplifying the manufacturing process.
Solution Approach 2:
The monolithic device structure serves multiple functions simultaneously - it emits multiple colors (blue, green, yellow) from a single device, eliminating the need for multiple separate LEDs. This multi-functionality is achieved through different quantum well regions with different band gaps within the same semiconductor structure.
3Adaptability or versatility
If phosphors are disposed on light emitting diodes to implement various colors, then color implementation is achieved, but device size increases
Solution Approach 1:
The patent integrates multiple color-emitting regions within a compact monolithic structure, eliminating the need for additional space required by phosphor materials and their supporting structures. The first and second color portions are vertically stacked within the same device footprint, reducing overall device size while maintaining color implementation capability.
4Device complexity
If conventional LED structures are used, then simple structure is maintained, but color coordinate stability deteriorates due to changes in current densities
Solution Approach 1:
The patent applies local quality by creating distinct quantum well regions with different band gaps (first color portion for blue light, second color portion for green or yellow light) within the monolithic device. Each region is optimized for its specific wavelength emission, and the tunnel barrier layer between them provides localized electron confinement, ensuring stable color coordinates across varying current densities.
Solution Approach 2:
The tunnel barrier layer acts as an intermediary between the first and second color portions, controlling electron flow and preventing carrier leakage between regions with different band gaps. This intermediary structure ensures that each color portion maintains its emission characteristics independently, stabilizing color coordinates despite current density changes.
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 monolithic di-chromic device achieves stable color implementation without phosphors, reducing color coordinate changes by up to 0.11 Δu′v′ across a 32 mA/cm2 to 120 mA/cm2 current density range, enabling efficient and compact multi-color LED modules.
Implementation Method 1
the first color portion emits light having a shorter wavelength than that of the second color portion
Implementation Method 2
the tunnel barrier layer may include an AlGaN layer or DBR
Data Source
AI summary
A monolithic di-chromic device and a light emitting module having the same are disclosed. A monolithic di-chromic device according to an embodiment of the present disclosure includes a first conductivity type semiconductor region; a control portion disposed on the first conductivity type semiconductor region; a color region formed on the control portion; and a second conductivity type semiconductor region disposed on the color region, in which the color region includes a first color portion and a second color portion, the first color portion emits light having a shorter wavelength than that of the second color portion, and the first color portion or the second color portion emits light having a plurality of peak wavelengths.