Stacked Micro LED Pixel Structure for Higher Brightness and Lower Crosstalk
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Solution Overview
Problem
Existing micro LED technology faces challenges in enhancing the effective illumination area within each pixel due to the large divergence angle of light emitted by micro LEDs, leading to reduced efficiency, brightness, light crosstalk, and loss of contrast in micro-LED display systems.
Innovation Solution
The integration of two or more vertically stacked micro LEDs with electrically connected layers and an integrated circuit back panel, along with reflecting layers, to improve light illumination efficiency and reduce optical crosstalk between pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If vertically stacked micro LEDs are integrated to improve illumination efficiency, then light illumination efficiency and brightness are improved, but device complexity increases
Solution Approach 1:
The patent transitions from a planar arrangement of micro LEDs to a three-dimensional vertically stacked configuration. Multiple micro LEDs are arranged along the vertical dimension (z-axis) rather than spreading them horizontally, allowing multiple light sources to occupy the same pixel area without lateral expansion. This dimensional change enables improved illumination efficiency while maintaining compact pixel dimensions.
Solution Approach 2:
The patent implements a nested structure where multiple micro LEDs are stacked vertically within each pixel, similar to nested dolls. Each micro LED is positioned at different vertical levels, with lower micro LEDs supporting upper ones. This nesting approach allows multiple light-emitting elements to be contained within a single pixel footprint, improving brightness without increasing pixel area.
2Measurement precision
If the distance between adjacent LEDs is reduced to improve resolution, then overall resolution is improved, but light crosstalk between pixels increases
Solution Approach 1:
The patent uses vertical stacking to separate light sources from adjacent pixels in the lateral direction. By arranging micro LEDs vertically within each pixel, the horizontal distance between effective light-emitting areas of adjacent pixels can be minimized while the vertical arrangement prevents lateral light spread. This dimensional separation reduces crosstalk while enabling higher pixel density.
Solution Approach 2:
The patent extracts and eliminates the problematic lateral light spread by confining light emission primarily to vertical directions through the stacked arrangement. The vertical stacking geometry naturally directs light output away from adjacent pixels, effectively removing the crosstalk issue that would otherwise occur with closely spaced lateral arrangements.
3Area of stationary object
If more micro LEDs are placed in each pixel to improve illumination area, then effective illumination area is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent achieves increased effective illumination area by exploiting the vertical dimension rather than expanding horizontally within the pixel plane. Multiple micro LEDs are stacked along the z-axis, allowing the cumulative light-emitting area to increase while the pixel footprint remains constant. This approach to increasing illumination area is less demanding on lateral alignment precision compared to placing multiple LEDs side-by-side in the same plane.
Solution Approach 2:
The patent segments the light-emitting function across multiple vertically stacked micro LEDs rather than using a single large LED or multiple lateral LEDs. Each micro LED in the stack contributes to the total illumination, and while individual alignment is important, the vertical segmentation allows for modular assembly and potential compensation techniques that may reduce overall manufacturing precision demands compared to lateral arrangements.
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 enhances light illumination efficiency within a single pixel area, improves the overall resolution of the micro LED panel, and reduces light crosstalk, resulting in increased brightness and contrast.
Implementation Method 1
the disclosed micro LED structure further improves the light illumination efficiency by including reflecting layers that not only effectively increase the amount of light emitted by each of the vertically stacked micro LEDs, but also reduce optical crosstalk between the vertically stacked micro LEDs
Data Source
AI summary
Micro LED structures and micro LED panels using the same are disclosed. A disclosed micro LED includes an IC back plane, and a stack of mesa structures comprising at least a first and a second mesa structures. The first mesa structure comprises: a first light-emitting layer, a first connecting layer formed on the first light-emitting layer, and a first conductive bonding layer formed under the first light-emitting layer and electrically connecting the first light-emitting layer to the IC back plane. The second mesa structure is formed on the first mesa structure and comprises: a second light-emitting layer, a second connecting layer formed on the second light-emitting layer, a second conductive bonding layer formed under the second light-emitting layer, and a third connecting layer formed under the second conductive bonding layer and electrically connected to the second light-emitting layer via the second conductive bonding layer.