Microdisplay Microcavity Structure for High Aperture Ratio
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current personal immersive microdisplays face challenges in achieving high resolution and brightness while maintaining a small size and lightweight design, essential for virtual and augmented reality applications, due to limitations in light-emitting area and aperture ratio.
Innovation Solution
The microdisplay incorporates a microcavity structure with a specific arrangement of dielectric layers and electrodes in each subpixel, maximizing light-emitting area and aperture ratio by varying the distance between reflecting and cathode electrodes, and using a bank to minimize coverage on the anode edges, thereby enhancing light amplification and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light-emitting area is increased to improve brightness, then the aperture ratio increases, but the device size increases making it unsuitable for wearable applications
Solution Approach 1:
The patent applies microcavity structures with specific cavity depths (e.g., 50-200 nm) to enhance light emission efficiency through optical resonance effects. By optimizing the cavity depth parameter to match specific wavelengths, the display achieves higher brightness without increasing the physical light-emitting area, thus maintaining small device size suitable for wearable applications.
Solution Approach 2:
The patent implements different cavity depths in different subpixels (Red, Green, Blue) to optimize light emission for each wavelength. The R subpixel has a first cavity depth, the G subpixel has a second cavity depth, and the B subpixel has a third cavity depth, allowing each subpixel to maximize its light output efficiency locally without increasing overall device area.
2Illumination intensity
If the aperture ratio is increased to improve light output, then brightness increases, but manufacturing precision requirements increase due to the complex microcavity structure
Solution Approach 1:
The patent divides the microcavity structure into discrete layers (first dielectric layer, second dielectric layer, organic light-emitting layer, electron transport layer, hole transport layer) that can be fabricated using standard thin-film deposition techniques. Each layer has a defined thickness range, allowing incremental fabrication with conventional manufacturing processes rather than requiring single-step high-precision fabrication.
Solution Approach 2:
The patent specifies thickness ranges for each layer (e.g., first dielectric layer: 10-50 nm, second dielectric layer: 10-50 nm, organic light-emitting layer: 20-100 nm) providing manufacturing tolerances that accommodate normal fabrication variations. This parameter specification approach enables mass production with standard precision equipment while maintaining the optical performance benefits of the microcavity structure.
3Illumination intensity
If the microcavity structure is implemented to maximize light emission in specific wavelengths, then brightness and color accuracy improve, but device complexity increases
Solution Approach 1:
The patent uses the same basic microcavity structure (dielectric layers + organic light-emitting layers + electrode layers) for all three subpixels (R, G, B). The universal structure is fabricated using the same deposition and patterning processes, and the only variation is the cavity depth parameter optimized for each wavelength. This multi-functional approach achieves wavelength-specific optimization without requiring different structures for each subpixel, thereby controlling device complexity.
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
This approach results in a high-aperture-ratio microdisplay with high brightness and ultra-high resolution, suitable for small, wearable devices, by maximizing light output in specific wavelength ranges and optimizing the light-emitting area, effectively addressing the limitations of existing technologies.
Implementation Method 1
an anode in which a reflecting electrode, a first dielectric layer, a second dielectric layer, and a transparent electrode are sequentially stacked
Implementation Method 2
the first dielectric layer and the second dielectric layer have contact portions that open at least one corner of the reflecting electrode
Data Source
AI summary
The disclosure relates to a high-aperture-ratio microdisplay with a microcavity structure. The microdisplay comprises a substrate, unit pixels, driving elements, and organic light-emitting diodes. The organic light-emitting diodes each comprise: an anode, an organic emission layer, and a cathode. The anode is formed by sequentially stacking a reflecting electrode, a first dielectric layer, a second dielectric layer, and a transparent electrode. The organic emission layer is stacked over the anode. The cathode is stacked over the organic emission layer. The first dielectric layer and the second dielectric layer have contact portion that open at least one corner of the reflecting electrode. The anode is connected to the reflecting electrode through the contact portions.