Light Emitting Array Structure with Detachable Redistribution Layer
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Solution Overview
Problem
The existing mass transfer techniques for micro-LEDs and micro-ICs in display pixel arrays are difficult to repair, as the redistribution layer (RDL) makes it challenging to replace defective components, leading to high costs and potential uneven color or brightness due to binning difficulties.
Innovation Solution
A light-emitting array structure with a substrate, light-emitting pixel units, signal wires, and an encapsulating layer, where each pixel unit includes a driver chip, flat layers, and redistribution layers, allowing for flip-chip bonding of light-emitting diodes and signal wires, enabling easy replacement and integration with improved surface flatness and optical efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mass transfer technique is used to bond micro-LEDs and micro-ICs via RDL, then integration is achieved, but repairability deteriorates because defective components cannot be removed without destroying the RDL
Solution Approach 1:
The invention divides the display structure into separable modules: the RDL is separated from the substrate and formed as an independent flexible layer. This segmentation allows the RDL to be detached and reattached during repair processes, enabling component replacement without permanent destruction of the interconnection structure.
Solution Approach 2:
The RDL is designed with dynamic characteristics - it can be flexibly detached and reattached to the substrate. This dynamic design transforms the static, permanent bonding into a reversible connection, allowing the RDL to be moved and repositioned for repair purposes while maintaining electrical connectivity when needed.
2Ease of operation
If RDL is destroyed to replace defective micro-LED or micro-IC, then component replacement is possible, but manufacturing complexity and cost deteriorate due to the need to recover and reconstruct the RDL
Solution Approach 1:
The RDL is pre-formed as a separate, flexible layer before being attached to the substrate. This preliminary preparation allows the RDL to be easily detached and reattached without requiring complex reconstruction processes, as the interconnection structure already exists in a ready-to-use state.
Solution Approach 2:
The invention enables easy recovery of the RDL after component replacement. The flexible RDL can be detached from the substrate, allowing defective components to be replaced, and then the same RDL can be reattached to complete the repair without needing to create a new interconnection structure.
3Manufacturing precision
If photolithography technique is used to manufacture RDL, then precise patterning is achieved, but repairability deteriorates because the photolithography-made RDL is difficult to modify or recover
Solution Approach 1:
The invention transitions the RDL from a planar, substrate-bound structure to a three-dimensional, flexible layer that can be detached and repositioned. This dimensional change allows the photolithography-formed pattern to be preserved while adding the capability to physically move and reattach the patterned layer for repair purposes.
4Ease of manufacture
If binning is not performed on micro-LEDs before bonding, then manufacturing simplicity is maintained, but product quality deteriorates due to uneven color and brightness in the pixel array
Solution Approach 1:
The invention separates the binning process from the bonding process. By organizing micro-LEDs into sorted groups (bins) before the bonding stage, the system maintains simple bonding operations while ensuring that only compatible components are grouped together, thereby achieving uniform color and brightness across the pixel array.
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 design simplifies the repair process, reduces costs, and ensures even brightness and color by allowing for easy replacement of defective components and improved manufacturing precision, while maintaining high light emission efficiency.
Implementation Method 1
The light-emitting diode is flip-chip bonded to and in contact with the second redistribution layer
Data Source
AI summary
Disclosed is a light-emitting array structure having a substrate, a plurality of light-emitting pixel units, a plurality of first signal wires, a plurality of second signal wires, and an encapsulating layer. The light-emitting pixel units are arranged in array on the substrate. Each light-emitting pixel unit includes a driving chip, a first flat layer, a first redistribution layer, a second flat layer, a second redistribution layer, and a light-emitting diode. Each first signal wire is electrically connected to a corresponding one of the first redistribution layers and extends in a first direction. The second signal wires extend in a level different from the first signal wires. Each second signal wire is electrically connected to a corresponding one of the second redistribution layers and extends in a second direction different from the first direction. The encapsulating layer covers the light-emitting pixel units, the first and second signal wires, and the substrate.