Flip-Chip Light Emitting Element for Interference-Based White Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light emitting elements that emit white light by stacking active layers for blue, green, and red light emission struggle to control the intensity of each color simultaneously and suffer from reduced light emission efficiency, making it difficult to achieve a balanced light output.
Innovation Solution
A flip-chip type light emitting element with a group III nitride semiconductor structure, featuring a substrate, n layer, first and second active layers with different emission wavelengths, a middle layer with controlled n-type impurity concentration, and a p layer that reflects light, allowing for interference-based control of light emission from each layer to amplify or attenuate specific colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple active layers are stacked to emit different colors simultaneously, then white light emission is achieved, but light emission efficiency and color balance control become difficult
Solution Approach 1:
The invention divides the light emission control into separate segments by stacking multiple active layers (first active layer emitting blue light, second active layer emitting green light, third active layer emitting red light) with middle layers between them. Each active layer can be independently optimized for its specific wavelength, allowing simultaneous emission of different colors while maintaining high efficiency for each segment.
Solution Approach 2:
The invention applies local quality by creating different impurity concentration profiles in different regions. The middle layers have specifically controlled impurity concentrations (1×10^18 cm^-3 or less) to minimize carrier leakage and recombination losses, while the active layers have optimized doping for their respective functions. This local optimization enables each layer to operate at peak efficiency.
2Adaptability or versatility
If multiple active layers are stacked to emit different colors simultaneously, then color diversity is achieved, but control of individual color intensity becomes difficult
Solution Approach 1:
By segmenting the device into separate active layers for different colors (blue, green, red) with intermediate middle layers, the invention enables independent control of each color's emission intensity. The middle layers act as isolation barriers that prevent carrier mixing between layers, allowing each active layer to be controlled independently through its respective electrode.
Solution Approach 2:
The middle layers serve as intermediary structures between adjacent active layers. These layers with low impurity concentrations (1×10^18 cm^-3 or less) function as carrier blocking barriers and optical isolation layers, enabling independent control of each active layer's emission while preventing unwanted interactions between layers.
3Illumination intensity
If active layers are stacked for blue, green, and red light emission, then white light is produced, but light output balance between colors is difficult to control
Solution Approach 1:
The invention achieves color balance control through local quality optimization by precisely controlling the impurity concentrations in middle layers (1×10^18 cm^-3 or less) and optimizing the thickness and composition of each active layer. This allows independent adjustment of emission intensity for blue, green, and red layers to achieve balanced white light output.
Solution Approach 2:
The invention utilizes parameter changes by adjusting the impurity concentration, thickness, and material composition of middle layers and active layers to control light emission characteristics. By changing these parameters, the emission intensity of each color can be independently tuned to achieve the desired white light balance.
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
Enables simultaneous emission of blue, green, and red light, allowing for controlled light output balance and enhanced light emission efficiency by adjusting the thickness of the p and middle layers to achieve amplified or attenuated light from specific active layers, resulting in effective white light emission.
Implementation Method 1
a p electrode that is provided over the p layer and is configured to reflect light
Implementation Method 2
light emitted from the second active layer causes interference between light directed toward the substrate and light directed toward the p electrode and reflected by the p electrode
Data Source
AI summary
In a flip-chip type light emitting element, light emitted from the second active layer causes interference between light directed toward the substrate and light directed toward the p electrode and reflected by the p electrode, and the interference is controlled based on a thickness of the p layer, light emitted from the first active layer causes interference between light directed toward the substrate and the light directed toward the p electrode and reflected by the p electrode, and the interference is controlled based on the thickness of the p layer and a thickness the middle layer, and the thickness of the p layer and the thickness of middle layer are set such that at least one of the light emitted from the first active layer or the light emitted from the second active layer is amplified by the interference.