Display Panel Pad Electrode Bonding Without Thermo-Compression

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Solution Overview

Problem

The bonding process between circuit units and display panels is prone to conductive short-circuits and incomplete connections due to the flow of conductive materials during thermos-compression, leading to unreliable signal transmission.

Innovation Solution

Exposing pad electrodes and applying solder to connect them one-to-one with connection electrodes on a circuit film, while using an insulating adhesive to fill spaces between these electrodes, thereby eliminating the need for thermos-compression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermos-compression process is used to bond circuit unit and display panel, then bonding process can be completed, but conductive material flows causing short-circuits between adjacent pads

Engineering Contradiction:

Improvebonding reliabilityVSAvoidconductive short-circuit

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the conductive material from the bonding interface by using exposed pad electrodes that extend beyond the circuit film boundary. This allows the pad electrodes to be bonded directly to the circuit film without requiring thermos-compression of conductive materials, thereby eliminating the source of conductive material flow that causes short-circuits.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using conductive material to bridge the circuit film and pad electrodes, the patent inverts the approach by having the pad electrodes themselves extend outwards to make direct contact with the circuit film. This reversal of the bonding mechanism eliminates the need for thermos-compression and prevents conductive material flow.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If thermos-compression process is used to bond circuit unit and display panel, then bonding can be achieved, but some pads are not connected to circuit unit

Engineering Contradiction:

Improveconnection reliabilityVSAvoidbonding precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The pad electrodes are pre-formed to extend beyond the circuit film boundary before the bonding process. This preliminary configuration ensures that the pad electrodes are already positioned for direct contact with the circuit film, eliminating the need for precise thermos-compression alignment and preventing connection failures.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If anisotropic conductive film is used for bonding, then bonding process can be completed, but conductive material flow causes short-circuits

Engineering Contradiction:

Improvebonding processabilityVSAvoidconductive short-circuit

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the mechanical thermos-compression process with a direct contact bonding method where exposed pad electrodes make physical contact with the circuit film. This substitution eliminates the need for anisotropic conductive films and their associated conductive material flow problems while maintaining ease of manufacture.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method enhances bonding reliability by preventing short-circuits and ensuring stable connections, particularly in high-resolution displays with fine-pitch structures, without the drawbacks of traditional thermos-compression processes.

Implementation Method 1

a plurality of solders to conductively connect the connection electrodes to the pad electrodes exposed from the circuit film one-to-one

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

an insulating adhesive to fill spaces between the pad electrodes and the connection electrodes, which do not come into contact with the solders, between the substrate and the circuit film

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS12506107B2Electronic device and display device using the same

Publication Date: 2025.12.23 LG DISPLAY CO LTD

AI summary

An electronic device can include a plurality of pad electrodes provided at at least one side of a substrate, at least one circuit film configured to have a plurality of connection electrodes provided at an insulating film to correspond to the plurality of pad electrodes, a plurality of solders to conductively connect the plurality of connection electrodes to the plurality of pad electrodes exposed from the circuit film one-to-one, and an insulating adhesive to fill spaces between the plurality of pad electrodes and the plurality of connection electrodes. Also, each of the plurality of solders has an edge horizontally protruding from the insulating film.