Stacked Micro-LED Pixel Structure for Full-Color High Resolution
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Solution Overview
Problem
Existing small-sized display panels face challenges in achieving high resolution and full color while maintaining a large light-emitting area due to limited pixel space, particularly in vertical stacking where wiring compromises light-emitting area.
Innovation Solution
A micro light-emitting device display apparatus with a stacked structure of first and second light-emitting layers, where the second layer emits two different wavelengths, reducing the space required for circuit wiring and improving spatial resolution, and utilizing a metal layer for bonding to facilitate simultaneous deposition of epitaxial structures in a single process step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If red, green, and blue sub-pixels are arranged in a vertical stacking manner to achieve full color and high resolution, then color performance and resolution are improved, but the light-emitting area is reduced due to wiring occupying limited pixel space
Solution Approach 1:
The patent transitions from planar lateral arrangement of sub-pixels to vertical stacking in the third dimension. Multiple light-emitting layers (first light-emitting layer with first epitaxial structure, second light-emitting layer with second and third epitaxial structures) are stacked vertically and bonded through a metal layer, allowing full-color emission while maintaining large lateral light-emitting area.
2Ease of operation
If traditional wiring methods are used in vertical stacking to connect sub-pixels, then electrical connections are established, but the wiring occupies valuable pixel space and reduces light-emitting area
Solution Approach 1:
The patent extracts and removes the traditional wiring structure from the pixel space. Instead of using lateral wiring to connect sub-pixels, the invention uses vertical bonding through metal layers to connect light-emitting layers, eliminating the need for wiring that would occupy pixel space and reduce light-emitting area.
3Manufacturing precision
If multiple photolithography processes are used to define epitaxial regions separately to achieve precise color emission, then color accuracy is improved, but alignment tolerances accumulate and manufacturing complexity increases
Solution Approach 1:
The patent merges multiple light-emitting structures into a single integrated device. The first epitaxial structure, second epitaxial structure, and third epitaxial structure are formed in one manufacturing process and bonded together through a metal layer, eliminating the need for multiple separate photolithography processes and reducing alignment tolerance accumulation.
Solution Approach 2:
The metal layer serves multiple functions simultaneously: it acts as a bonding layer to connect the first and second light-emitting layers, and as an electrical connection layer to provide electrical pathways between the epitaxial structures. This multi-functionality simplifies the overall device structure and manufacturing process.
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 enhances light-emitting efficiency and reduces alignment tolerances, allowing for improved spatial resolution and increased light-emitting area without the need for multiple photolithography processes.
Implementation Method 1
The second light-emitting layer is bonded and stacked onto the first light-emitting layer through a metal layer
Implementation Method 2
The first epitaxial structure is configured to emit light of a first wavelength. The second epitaxial structure is configured to emit light of a second wavelength and the third epitaxial structure is configured to emit light of a third wavelength
Data Source
AI summary
A micro light-emitting device display apparatus includes a plurality of micro light-emitting devices. Each micro light-emitting device includes a first light-emitting layer including a first epitaxial structure configured to emit light of a first wavelength and a second light-emitting layer bonded and stacked onto the first light-emitting layer through a metal layer, and including a second epitaxial structure configured to emit light of a second wavelength and a third epitaxial structure configured to emit light of a third wavelength. The second epitaxial structure and the third epitaxial structure are nanorod arrays of a same epitaxial material. The third wavelength is greater than the second wavelength. Both the second wavelength and the third wavelength are less than the first wavelength. A sum of orthographic projection areas of the second epitaxial structure and the third epitaxial structure is less than an orthographic projection area of the first epitaxial structure.