Micro-LED Pixel Structure With Vertical Stacking for Red Intensity
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Solution Overview
Problem
Micro-LED displays face challenges in reducing the number of micro-LEDs while maintaining red light intensity, as the small size of micro-LEDs makes them difficult to transfer and mount on a single circuit board, leading to relatively low red light intensity in pixel modules.
Innovation Solution
A pixel device design featuring a first light emitting device with a longer peak wavelength and a second and third light emitting device with different peak wavelengths, stacked vertically, and connected via bonding layers, to enhance red light intensity without increasing the number of micro-LEDs, using arsenide or phosphide-based semiconductor layers for the first device and nitride-based layers for the others, with specific conductivity type semiconductor layers and electrode pads for efficient electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If micro-LEDs are made smaller to increase pixel density, then pixel density is improved, but the number of micro-LEDs to be mounted increases making transfer and mounting difficult
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement of micro-LEDs to a three-dimensional vertical stacking configuration. Multiple light emitting devices are stacked vertically within a single pixel module, allowing the system to achieve higher pixel density without increasing the number of separate micro-LED chips that need to be transferred and mounted on the substrate.
Solution Approach 2:
The patent combines multiple light emitting devices (first light emitting device with longer peak wavelength, second light emitting device, and third light emitting device) into a single integrated pixel module structure. This merging allows multiple functions to be achieved within one pixel unit, reducing the total number of separate components required.
2Ease of manufacture
If the number of micro-LEDs is reduced to simplify mounting, then ease of manufacture is improved, but red light intensity decreases
Solution Approach 1:
The patent uses vertical stacking to increase the effective light emitting area for red light without requiring additional horizontal space or more separate chips. The first light emitting device with longer peak wavelength (red light) is stacked vertically, allowing its light to be emitted through the bonding layer and cover layer, thereby maintaining or enhancing red light intensity while using fewer discrete micro-LED components.
Solution Approach 2:
The patent employs a composite structure with different semiconductor materials (arsenide or phosphide-based for the first light emitting device, nitride-based for the second and third light emitting devices) to optimize light emission characteristics. This material composition allows the red light emitting device to maintain high intensity while integrated into a compact multi-device structure.
3Ease of manufacture
If multiple light emitting devices are stacked vertically to reduce micro-LED count, then ease of manufacture is improved, but device complexity increases
Solution Approach 1:
The patent segments the pixel device into distinct functional components (first light emitting device, second light emitting device, third light emitting device, bonding layer, cover layer) that can be manufactured and characterized separately before integration. This segmentation allows for specialized optimization of each component while maintaining overall manufacturability.
Solution Approach 2:
The bonding layer and cover layer serve multiple functions: they provide mechanical support, enable light transmission, facilitate electrical connections, and protect the light emitting devices. This multi-functionality reduces the need for additional separate components, thereby managing device complexity while achieving vertical integration.
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 configuration allows for increased red light intensity and reduced micro-LED count, improving emission efficiency and pixel density in micro-LED displays.
Implementation Method 1
the first light emitting structure emitting light having a longer peak wavelength than peak wavelengths of light emitted from the second and third light emitting structures
Implementation Method 2
the second and third light emitting structures emitting light having different peak wavelengths
Implementation Method 3
a bonding layer bonding the second light emitting structure to the third light emitting structure
Data Source
AI summary
A pixel device includes a first light emitting device; a second light emitting device horizontally disposed adjacent to the first light emitting device; a first cover layer covering the first light emitting device and the second light emitting device; and connection layers disposed on the first cover layer and electrically connected to the first and second light emitting devices, wherein the first light emitting device includes a first light emitting structure, and the second light emitting device includes a second light emitting structure and a third light emitting structure, the first light emitting structure emitting light having a longer peak wavelength than peak wavelengths of light emitted from the second and third light emitting structures, the second and third light emitting structures emitting light having different peak wavelengths.