Dual Red Emitter Display Structure for Vivid Low-Power Images
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Solution Overview
Problem
Conventional red LEDs with a multi-quantum well structure made of gallium nitride (GaN) have lower luminous efficacy compared to blue and green LEDs, requiring higher drive currents and resulting in increased power consumption, and struggle to display vivid images due to a narrower light spectrum.
Innovation Solution
A display device incorporating a substrate with pixels featuring a first light emitting element with a gallium nitride light emitting layer doped with europium and a second light emitting element with a multi-quantum well structure of indium gallium nitride and gallium nitride, allowing for improved red light emission and spectrum width, thereby enhancing image display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a multi-quantum well structure made of gallium nitride is used for red LEDs, then the device can emit red light, but the luminous efficacy is lower compared to blue and green LEDs
Solution Approach 1:
The patent uses a composite light emitting layer combining gallium nitride with europium dopant. The europium ions are incorporated into the gallium nitride crystal structure, creating a composite material that leverages the bandgap properties of GaN for red light emission while europium provides enhanced luminescence efficiency, thereby improving luminous efficacy and reducing power consumption
Solution Approach 2:
The patent modifies the compositional parameters of the gallium nitride material by introducing europium as a dopant at specific concentrations. This parameter change alters the optical and electrical properties of the material, enabling improved radiative recombination efficiency and higher luminous efficacy for red light emission
2Illumination intensity
If europium is added to gallium nitride for red LED, then luminous efficacy improves, but the half width of light spectrum becomes narrower
Solution Approach 1:
The patent employs multiple red light emitting elements with different spectral characteristics in combination. By segmenting the red light emission into multiple sources with slightly different spectrum widths and peak wavelengths, the system achieves both high luminous efficacy (from europium-doped GaN) and adequate spectrum width for vivid image display
3Illumination intensity
If higher drive current is supplied to red LED, then luminous output increases, but power consumption increases
Solution Approach 1:
The patent changes the material composition parameters by incorporating europium into gallium nitride, which fundamentally alters the electroluminescence efficiency. This parameter change enables higher luminous output at lower drive currents, breaking the direct proportionality between drive current and power consumption that characterizes conventional red LEDs
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 proposed solution improves the luminous efficacy of red LEDs, reduces power consumption, and enables more accurate and vivid image display by utilizing a combination of europium-doped gallium nitride and indium gallium nitride-based multi-quantum well structures in the display device.
Implementation Method 1
A first light emitting element 3Ra and a second light emitting element 3Rb that emit first red light and second red light, respectively
Implementation Method 2
a light emitting layer of the second light emitting element includes a multi-quantum well structure in which indium gallium nitride and gallium nitride are layered
Data Source
AI summary
According to an aspect, a display device includes: a substrate; a plurality of pixels provided on the substrate; and a first light emitting element and a second light emitting element that are included in each of the pixels. A light emitting layer of the first light emitting element includes gallium nitride to which europium is added, and a light emitting layer of the second light emitting element includes a multi-quantum well structure in which indium gallium nitride and gallium nitride are layered.