Stacked Micro-LED Chip Structure for Faster Sub-Pixel Mounting
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Solution Overview
Problem
The challenge in manufacturing micro-LED displays is the complexity and time required for mounting individual LED chips, due to their small size and vulnerable structure, which also affects the brightness of sub-pixels.
Innovation Solution
A light emitting chip with a stacked structure is developed, featuring a first LED sub-unit, a second LED sub-unit, and a third LED sub-unit, along with a passivation layer and connection electrodes. The connection electrodes are designed to form specific angles with the LED sub-units, providing protection and simplifying the mounting process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If individual LED chips are arranged on a two-dimensional plane for each sub-pixel, then color display capability is achieved, but the number of LED chips required becomes very large and mounting complexity increases significantly
Solution Approach 1:
The patent transitions from a two-dimensional arrangement of individual LED chips to a three-dimensional stacked structure where multiple LED sub-units (first, second, and third LED sub-units) are vertically stacked. This dimensional change allows multiple color-emitting elements to occupy a smaller footprint area, reducing the total number of chips needed while maintaining full-color display capability through the stacked configuration.
Solution Approach 2:
The patent combines multiple LED sub-units into a single integrated light emitting chip structure. The first, second, and third LED sub-units are merged vertically with shared connection electrodes and passivation layers, creating one functional unit that replaces multiple separate chips. This merging reduces mounting complexity while preserving color display functionality.
2Manufacturing precision
If one LED chip is provided for each sub-pixel, then color accuracy is maintained, but the time required for mounting process becomes very long
Solution Approach 1:
Multiple LED sub-units are merged into a single stacked structure that functions as one integrated chip. This allows the mounting process to install one stacked chip instead of multiple individual chips, significantly reducing mounting time while maintaining color accuracy through the precise vertical integration of sub-units with different emission wavelengths.
Solution Approach 2:
The LED sub-units are pre-integrated into a stacked configuration during manufacturing, with connection electrodes and passivation layers already in place. This preliminary assembly reduces the complexity and time of the final mounting process, as the entire stacked structure is installed as a single unit rather than assembling multiple separate components at the mounting stage.
3Adaptability or versatility
If sub-pixels are arranged on a two-dimensional plane, then color display is achieved, but a relatively large area is required for one pixel and luminous area is reduced
Solution Approach 1:
The patent utilizes vertical stacking to arrange multiple LED sub-units in the third dimension rather than spreading them out on a two-dimensional plane. This allows the first, second, and third LED sub-units to occupy overlapping horizontal footprints while maintaining distinct vertical positions, dramatically reducing the total area required per pixel while preserving full-color display capability.
Solution Approach 2:
The LED sub-units are nested vertically within a compact stacked structure, where each sub-unit is positioned above the previous one. This nesting arrangement allows multiple color-emitting elements to share the same horizontal space, minimizing the pixel area while maintaining color display functionality through the stacked configuration.
4Manufacturing precision
If micro-LEDs are made very small in size, then display resolution is improved, but handling during transferring becomes difficult due to vulnerable structure
Solution Approach 1:
Multiple fragile micro-LED sub-units are merged into a single stacked structure with shared connection electrodes and passivation layers. This integration creates a more robust unit that is easier to handle during transferring operations compared to individual micro-LED chips, while maintaining high display resolution through the compact vertical arrangement.
Solution Approach 2:
The passivation layer is applied beforehand to protect the vulnerable LED sub-units and connection electrodes during handling and transferring. This protective layer cushions the fragile structures against mechanical damage, enabling easier handling of the miniaturized stacked chip while preserving the high resolution benefits of small size.
Data Source
AI summary
A light emitting device including a board, a first stacked structure configured to emit light having a first wavelength, a second stacked structure configured to emit light having a second wavelength, a third stacked structure configured to emit light having a third wavelength, a first connection electrode electrically connected to the first stacked structure, the second stacked structure, and the third stacked structure, and a protection material covering at least a portion of the first connection electrode, in which each of the first, second, and third stacked structures is configured to selectively emit light while being connected to the first connection electrode, and the protection material is configured to transmit at least 50% of light having the first wavelength, light having the second wavelength, and light having the third wavelength upon operation of each of the first, second, and third stacked structures.