Micro LED Display Pad Structure for Stable Bonding and Repair
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Solution Overview
Problem
Existing display modules face challenges in stabilizing connections between substrate electrode pads and chip electrode pads of micro LEDs, leading to unlit errors and inefficiencies in micro light-emitting diode (LED) performance, particularly in ultrafine pitch arrangements where conductive balls can cause shorts and alignment difficulties.
Innovation Solution
The display module incorporates substrate electrode pads with alternating regions for contact protrusions and a redundancy area for repair micro LEDs, featuring elastic cores and capping layers to ensure secure electronic and physical connections, reducing manufacturing costs and improving reliability through the use of non-conductive adhesion layers and thermo-compression bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional substrate electrode pads with conductive balls are used for micro LED connections, then alignment and connection can be achieved, but unlit errors increase and connection stability deteriorates due to shorts and alignment difficulties in ultrafine pitch arrangements
Solution Approach 1:
The patent removes the conductive balls from the substrate electrode pad structure entirely. Instead of using traditional conductive balls for electrical connection, the invention employs direct contact between the chip electrode pads and the substrate electrode pad surface, eliminating the alignment and short-circuit problems associated with conductive balls in ultrafine pitch arrangements.
Solution Approach 2:
The substrate electrode pads are pre-formed with specific patterns and structures before micro LED mounting. The pads include designated contact regions and redundancy areas that are prepared in advance to ensure proper electrical connection and facilitate repair operations, improving both connection reliability and manufacturability.
2Ease of repair
If redundancy areas are added to substrate electrode pads for repair micro LEDs, then repair capability improves, but device complexity increases
Solution Approach 1:
The substrate electrode pads serve multiple functions: they provide electrical connection for operational micro LEDs, serve as mounting locations for repair micro LEDs through redundancy areas, and maintain structural integrity. This multi-functionality enables repair capability without requiring entirely separate repair mechanisms, thus limiting the increase in device complexity.
Solution Approach 2:
The substrate electrode pads feature localized redundancy areas with specific contact protrusion patterns designed for repair operations. These redundancy areas are strategically positioned and structured to enable repair micro LED attachment only where needed, rather than complicating the entire pad structure. The contact protrusions in redundancy areas follow the same design principles as operational areas, maintaining structural consistency.
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 solution enhances the stability and reliability of connections between substrate and chip electrode pads, minimizing unlit errors and alignment issues, while allowing for efficient repair of defective micro LEDs, thus improving the overall performance and durability of the display module.
Implementation Method 1
An elastic core may be provided on inner sides of the plurality of contact protrusions
Implementation Method 2
a capping layer provided on each substrate electrode pad of the plurality of substrate electrode pads and configured to prevent oxidation of the plurality of substrate electrode pads
Implementation Method 3
thermo-compressing the plurality of micro LEDs such that chip electrode pads included in each of the plurality of micro LEDs are connected to the plurality of contact protrusions of a corresponding substrate electrode pad
Data Source
AI summary
A display module includes a substrate, a plurality of substrate electrode pads provided on the substrate, and a plurality of micro light-emitting diodes (LEDs) connected to the plurality of substrate electrode pads, where each of the plurality of substrate electrode pads includes a first region in which a plurality of contact protrusions are formed, and a second region configured to be connected with a repair micro LED.