Micro-LED Pixel Array Bonding for High-Resolution Display Layouts
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Solution Overview
Problem
Current display technologies face challenges in achieving high resolution and miniaturization while maintaining easy manufacturing processes, particularly in the arrangement and bonding of LED cells within display apparatuses.
Innovation Solution
The display apparatus incorporates a circuit substrate with driver circuits and a pixel array featuring LED cells with specific semiconductor layer structures and electrode configurations, including a first electrode covering upper surfaces of LED cells and second electrodes on lower surfaces, optimized through a fluidic transfer process for hybrid bonding, enabling high resolution and reduced size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If LED cells are arranged with different levels for different sub-pixels, then resolution and miniaturization are improved, but manufacturing complexity increases
Solution Approach 1:
The patent divides the pixel array into different regions with different LED cell configurations. Specifically, first sub-pixels (red and blue) use LED cells with a first level height, while second sub-pixels (green) use LED cells with a second level height. This segmentation allows each region to be optimized for its specific color requirements while maintaining overall manufacturing feasibility through standardized processes.
Solution Approach 2:
The patent implements local quality by assigning different structural characteristics to different parts of the pixel array. The first LED cells (for red and blue sub-pixels) have a specific height level, while the second LED cells (for green sub-pixels) have a different height level. This local differentiation optimizes the display performance for each color while managing the overall device complexity.
2Manufacturing precision
If multiple electrode layers are added for different LED cell levels, then electrical connection precision is improved, but device complexity increases
Solution Approach 1:
The patent addresses the electrical connection challenge by introducing a vertical dimension solution. Instead of adding multiple horizontal electrode layers that would increase planar complexity, the patent uses a single first electrode that extends horizontally across different levels and makes electrical contact with multiple LED cells at different heights. This dimensional approach simplifies the electrode structure while maintaining precise electrical connections.
Solution Approach 2:
The first electrode serves multiple functions: it provides electrical connection to first LED cells at the first level, extends horizontally to reach second LED cells at the second level, and maintains a uniform upper surface for subsequent processing steps. This multi-functionality reduces the need for separate electrode structures for each LED cell type.
3Manufacturing precision
If LED cells of different sizes are used for different sub-pixels, then display performance is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent applies local quality by configuring first LED cells with specific dimensions for red and blue sub-pixels, while second LED cells have different dimensions optimized for green sub-pixels. Each LED cell type is locally optimized for its color requirements, with the first LED cells having dimensions suitable for red and blue emission, and second LED cells having dimensions optimized for green emission.
Solution Approach 2:
The patent implements preliminary action by pre-configuring LED cells with different dimensions before they are transferred to the substrate. The first and second LED cells are prepared in advance with their respective optimal dimensions, then transferred and positioned in their target locations using fluidic transfer technology. This preliminary preparation simplifies the manufacturing process by avoiding complex on-site dimension adjustments.
Data Source
AI summary
A display apparatus, including a circuit substrate including driver circuits and first bonding electrodes, and a pixel array on the circuit substrate and including a plurality of pixels each including first to third sub-pixels, and second bonding electrodes bonded to the first bonding electrodes, the pixel array further including, a plurality of first LED cells corresponding to the first and third sub-pixels, respectively, and each including a first conductivity-type semiconductor layer, a first active layer, and a second conductivity-type semiconductor layer, a plurality of second LED cells corresponding to the second sub-pixels, respectively, and each including the first conductivity-type semiconductor layer, a second active layer, and the second conductivity-type semiconductor layer, a first electrode extending to cover upper surfaces of the plurality of first and second LED cells and connected to the first conductivity-type semiconductor layers in common.