Active Matrix Substrate Lead Layout for Leak-Free Laser Separation

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Solution Overview

Problem

In display devices like organic electroluminescence (EL) displays, the narrow spacing between electrical leads and terminals leads to issues during the separation process, where the polyimide substrate can burn and become electrically conductive, causing leaks between terminals.

Innovation Solution

The active matrix substrate features first lead wires extending to the display region and second lead wires extending to a separation line, with the second lead wires arranged at a greater pitch than the first lead wires, preventing electrical leaks by ensuring the resin substrate does not carbonize and conduct electricity between terminals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the electrical leads are arranged with narrow spacing to achieve high definition display, then the terminal spacing and electrical-lead spacing are reduced, but the polyimide substrate burns and becomes electrically conductive during laser separation, causing electric leaks between terminals

Engineering Contradiction:

Improvedisplay definitionVSAvoidelectrical insulation between terminals

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent divides the lead wire structure into two distinct types: first lead wires with narrow pitch for signal transmission to the display region, and second lead wires with wide pitch extending to the separation line. This segmentation allows the functional leads to maintain narrow spacing while the separation-critical leads are spaced to prevent carbonization and electrical leakage during laser cutting.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different pitch characteristics to different regions of the lead wire structure. The first lead wires maintain narrow pitch throughout their length for optimal signal transmission, while the second lead wires transition to wide pitch specifically in the region extending to the separation line, where they are subject to laser cutting. This local differentiation of geometric properties prevents electrical leakage at the separation zone while preserving high definition display capabilities.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If the narrow spacing is maintained during laser separation, then the high definition display is achieved, but the resin substrate carbonizes and becomes electrically conductive, causing short circuits

Engineering Contradiction:

Improvelead wire spacing consistencyVSAvoidsubstrate carbonization and electrical conductivity

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent incorporates the second lead wires with wide pitch into the structure before the laser separation process. This preliminary arrangement of widely-spaced second lead wires creates a geometric configuration that prevents excessive heat concentration and carbonization during laser cutting, thereby maintaining the insulating properties of the resin substrate and preventing electrical shorts between terminals.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the second lead wires are arranged with greater pitch than the first lead wires, then electrical leaks are prevented during separation, but the device complexity increases due to dual lead wire configurations

Engineering Contradiction:

Improveelectrical insulation during separationVSAvoiddual lead wire arrangement

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The second lead wires serve multiple functions: they provide electrical connection during the manufacturing process, act as structural support elements, and function as heat dissipation paths during laser separation. By making these elements multi-functional, the patent reduces the need for additional separate components, thereby limiting the increase in device complexity despite the dual lead wire configuration.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 configuration effectively prevents electrical leaks between terminals, ensuring the integrity of the display device by maintaining the insulating properties of the resin substrate during the separation process.

Implementation Method 1

the short ring is separated with, for example, a laser beam or a diamond cutter

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentUS11908873B2Active matrix substrate, display device, and motherboard

Publication Date: 2024.02.20 SHARP KK

AI summary

An active matrix substrate including a resin substrate including a plurality of external connection terminals arranged near a display region, the active matrix substrate includes: a plurality of first lead wires each extending from one of the external connection terminals to the display region; and a plurality of second lead wires each extending from one of the external connection terminals to a separation line, the second lead wires being arranged with an arrangement pitch along the separation line, and the arrangement pitch of the second lead wires being greater than an arrangement pitch of the first lead wires.