Stacked LED Pixel Layout for High-Resolution Full-Color Emission
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Solution Overview
Problem
Micro-LED displays face challenges in mounting and achieving high-resolution, full-color reproduction due to the small size of micro-LEDs, requiring a method to increase light emitting area without increasing pixel area and simplify manufacturing.
Innovation Solution
A light emitting stacked structure with epitaxial sub-units of different colors, where each sub-unit has a unique light emitting area that overlaps others, allowing for independent driving and high light transmission efficiency, enabling the combination of red, green, and blue light emissions in a compact form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If micro-LEDs are arranged on a two-dimensional plane to achieve high-resolution display, then the number of micro-LEDs required increases to hundreds of thousands or millions, but the mounting difficulty increases significantly due to the very small size of each micro-LED
Solution Approach 1:
The patent transitions from a two-dimensional arrangement of micro-LEDs to a three-dimensional stacked structure where multiple micro-LEDs are vertically stacked. This dimensional change allows multiple light-emitting elements to occupy a smaller footprint area, achieving high resolution without requiring mounting of hundreds of thousands of individual micro-LEDs on a flat surface.
Solution Approach 2:
The patent combines multiple micro-LEDs into a single stacked structure where they share common bonding pads and mounting interfaces. This merging reduces the number of discrete mounting operations required, as the stacked structure can be mounted as a single unit rather than individually mounting each micro-LED.
2Measurement precision
If the area of each micro-LED is kept very small (10,000 square micrometers or less) to achieve high resolution, then the pixel area is reduced, but the light emitting area becomes insufficient for achieving high color purity and brightness
Solution Approach 1:
The stacked structure extends the light-emitting volume into the third dimension (vertical direction). Multiple micro-LEDs stacked vertically provide cumulative light-emitting area while maintaining a small footprint, thus achieving both high resolution and sufficient brightness/color purity simultaneously.
Solution Approach 2:
The patent implements a nested configuration where multiple micro-LEDs are stacked one on top of another, with each micro-LED containing or supporting the next. This nesting allows the light-emitting areas to be combined vertically while occupying minimal horizontal space.
3Manufacturing precision
If individual mounting of light emitting diodes is performed to achieve precise positioning, then the positioning accuracy is improved, but the manufacturing complexity and time increase significantly
Solution Approach 1:
The patent merges multiple micro-LEDs into a stacked structure that can be mounted as a single unit using common bonding pads. This reduces the number of individual mounting operations from hundreds of thousands to a manageable number, significantly improving manufacturing efficiency while maintaining positioning accuracy through the structured arrangement.
Solution Approach 2:
The stacked structure of micro-LEDs can be pre-assembled and tested before final mounting, allowing preliminary positioning and electrical connection verification. This preliminary action reduces the complexity of the final mounting process and ensures positioning accuracy is achieved more efficiently.
4Illumination intensity
If a stacked structure with overlapping light emitting areas is used to increase light emitting area per pixel, then the color purity and brightness are improved, but the structural complexity increases
Solution Approach 1:
The patent segments the pixel structure into multiple discrete stacked layers, each containing micro-LEDs that emit different colors. This segmentation allows independent optimization of each layer's light-emitting characteristics while maintaining overall structural organization, managing complexity through modular design.
Solution Approach 2:
The stacked structure uses common bonding pads and mounting interfaces for multiple micro-LEDs, creating universal connection points that simplify the overall structure. This multi-functionality reduces the number of discrete components and connections required, managing structural complexity while achieving enhanced light-emitting performance.
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 enhances light extraction efficiency and simplifies manufacturing by allowing for high-resolution, full-color displays with improved color purity and reproducibility in a smaller form factor.
Implementation Method 1
each of the epitaxial sub-units configured to emit different colored light
Implementation Method 2
Light emitted from a lower epitaxial sub-unit may be configured to be emitted to the outside of the light emitted stacked structure by passing through an upper epitaxial sub-unit disposed on the lower epitaxial sub-unit
Data Source
AI summary
A light emitting diode pixel for a display including a first LED sub-unit, a second LED sub-unit disposed on a first portion of the first LED sub-unit, and a third LED sub-unit disposed on a second portion of the second LED sub-unit, in which each of the first, second, and third LED sub-units includes a first conductivity type semiconductor layer and a second conductivity type semiconductor layer, light generated from the first LED sub-unit is configured to be emitted outside of the light emitting diode pixel through a third portion of the first LED sub-unit different from the first portion, and light generated from the second LED sub-unit is configured to be emitted outside of the light emitting diode pixel through a fourth portion of the second LED sub-unit different from the second portion.