Multilayer Resonant Cavity Light Reflective Structure for Microdisplays
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Solution Overview
Problem
Current light emitting devices, such as OLEDs, face challenges in achieving improved optical properties like resolution, luminance, and light emitting efficiency, particularly in microdisplays used in VR and AR applications, where existing technologies struggle to enhance light extraction and color purity effectively.
Innovation Solution
A light emitting device design featuring a substrate with a multilayer resonant cavity structure and via plugs connected to light reflective layers, which includes a stack of light reflective layers with varying widths and thicknesses, enhancing light reflection and constructive interference to improve light extraction efficiency and color purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional single-layer reflective structure is used, then the device complexity is low, but the light extraction efficiency and color purity are insufficient
Solution Approach 1:
The reflective layer is divided into multiple sub-reflective layers (first reflective layer, second reflective layer, third reflective layer) with different reflectivity characteristics. Each layer targets specific wavelength ranges, segmenting the light reflection function to achieve broader spectral control and improved color purity while maintaining reasonable manufacturing complexity.
Solution Approach 2:
The patent employs a composite reflective structure combining multiple materials with different optical properties (silver, aluminum, dielectric materials) in a stacked configuration. This composite approach enables tailored reflectivity profiles across different wavelengths, significantly enhancing light extraction efficiency and color purity compared to single-material structures.
2Ease of manufacture
If a conventional single-layer reflective structure is used, then the manufacturing process is simple, but the color purity is insufficient
Solution Approach 1:
The reflective function is segmented across multiple layers, each optimized for specific color wavelengths. The first reflective layer handles broad-spectrum reflection, the second layer enhances specific color ranges, and the third layer fine-tunes the spectral output. This segmentation enables precise color control through standard semiconductor fabrication processes.
Solution Approach 2:
The patent optimizes multiple parameters including layer thicknesses (ranging from 50nm to 200nm), material compositions, and spacing between layers to achieve desired color purity. By adjusting these parameters within standard manufacturing tolerances, high color purity is achieved without requiring ultra-precise or non-standard fabrication processes.
3Volume of moving object
If the light reflective layers are disposed close to each other, then the device structure is compact, but the light reflection and constructive interference effects are reduced
Solution Approach 1:
The patent optimizes the vertical spacing between reflective layers in the z-dimension to enable constructive interference of reflected light waves. By positioning layers at specific distances (50nm-200nm spacing), the optical path difference between reflections from different layers creates constructive interference for desired wavelengths, enhancing light reflection efficiency while maintaining compact overall device volume.
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 solution results in improved light emitting efficiency, increased luminance, and enhanced color purity, allowing for lower power consumption and better performance in microdisplay applications like VR and AR.
Implementation Method 1
first light reflective layers including a first lower light reflective layer, a first intermediate light reflective layer on the first lower light reflective layer, and a first upper light reflective layer on the first intermediate light reflective layer
Implementation Method 2
enhancing light reflection and constructive interference to improve light extraction efficiency and color purity
Data Source
AI summary
A light emitting device includes a substrate; a circuit region including a circuit device on the substrate; an insulating layer on the circuit region; a first light emitting region connecting portion, a second light emitting region connecting portion, and a third light emitting region connecting portion, in the insulating layer; and a light emitting portion including a first light emitting region on the first light emitting region connecting portion, a second light emitting region on the second light emitting region connecting portion, and a third light emitting region on the third light emitting region connecting portion, the first light emitting region connecting portion includes first light reflective layers including a first lower light reflective layer, a first intermediate light reflective layer on the first lower light reflective layer, and a first upper light reflective layer on the first intermediate light reflective layer, and at least one first via plug connected to the first light emitting region, the second light emitting region connecting portion includes second light reflective layers including a second lower light reflective layer, and a second upper light reflective layer on the second lower light reflective layer, and at least one second via plug connected to the second light emitting region, and the third light emitting region connecting portion includes a third light reflective layer, and a third via plug connected to the third light emitting region.