Monolithic Display Layer Layout for High-PPI Bonding Yield
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Solution Overview
Problem
As pixel density increases in micro LED display modules, the gap between bonding pads decreases, making bonding surface processing and alignment operations more difficult, leading to a decrease in manufacturing yield.
Innovation Solution
A display layer with a monolithic structure is introduced, where light-emitting devices and switching devices form a unified structure without a bonding layer, allowing for a wider gap between bonding pads, and driving signals are applied through a driving layer with shared driving devices and switch control blocks to manage signal distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel density is increased, then display resolution is improved, but the gap between bonding pads decreases making bonding and alignment more difficult
Solution Approach 1:
The patent merges the light-emitting device layer and switching device layer into a single monolithic display layer, eliminating the need for separate bonding processes. This integration allows the bonding pads to be positioned with larger spacing since they no longer need to align with sub-pixel level precision, thereby resolving the alignment difficulty while maintaining high display resolution
Solution Approach 2:
The patent transitions from a planar arrangement where bonding pads must align precisely with sub-pixels to a three-dimensional monolithic structure where driving devices are positioned in a separate driving layer. This dimensional separation allows bonding pads to be spaced farther apart while still maintaining electrical connection to the appropriate sub-pixels through the vertical stacking architecture
2Measurement precision
If pixel density is increased, then display resolution is improved, but manufacturing yield decreases due to bonding difficulty
Solution Approach 1:
By merging the light-emitting devices and switching devices into a single monolithic display layer manufactured through a unified process, the patent eliminates the separate bonding step that causes yield loss. This integration ensures that all components are fabricated simultaneously with consistent alignment, thereby maintaining high manufacturing yield while achieving high pixel density
Solution Approach 2:
The patent incorporates switching devices and their connection structures into the display layer during the initial manufacturing process, before the bonding to the driving layer occurs. This preliminary integration of critical components ensures that alignment is established during the high-precision manufacturing process rather than during the subsequent bonding process, thereby preserving manufacturing yield
3Adaptability or versatility
If separate manufacturing and bonding processes are used, then device functionality is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent combines multiple manufacturing steps into a single monolithic fabrication process where light-emitting devices, switching devices, and their interconnections are all formed in the same display layer. This merging of manufacturing operations reduces process complexity and cost while maintaining full device functionality through the integrated structure
Solution Approach 2:
The monolithic display layer serves multiple functions simultaneously: it acts as the light-emitting layer, the switching layer, and the connection layer. This multi-functionality eliminates the need for separate manufacturing processes for each layer, thereby reducing overall manufacturing complexity while preserving all necessary device functions
Data Source
AI summary
A display device includes a display layer including a plurality of light-emitting devices and a plurality of switching devices in a one-to-one correspondence with the light-emitting devices, the plurality of light-emitting devices and the plurality of switching devices forming a monolithic structure, and a driving layer, wherein the plurality of light-emitting devices and the plurality of switching devices corresponding to the plurality of light-emitting devices are grouped into pixels and then arranged in the display layer, and the driving layer includes a plurality of driving devices configured to apply at least one driving signal to the display layer.