Pixel Array Substrate Testing Element for Sidewall Wiring

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Solution Overview

Problem

The manufacturing process of light-emitting diode display panels faces a yield reduction due to the damage of side pads during the testing of sidewall wiring, which is necessary for ensuring the normal operation of the wiring.

Innovation Solution

A pixel array substrate design that includes separate testing elements and pads on both surfaces of the base, allowing for testing without direct contact with the bonding pads, thereby preventing damage during the testing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a probe is brought into contact with the side pads to test the sidewall wiring, then the wiring functionality can be verified, but the side pads are readily damaged resulting in decreased yield

Engineering Contradiction:

Improvewiring functionality verificationVSAvoidmanufacturing yield

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent introduces testing elements as intermediary components that are electrically connected to the sidewall wiring through wirings, rather than directly contacting the side pads. These testing elements serve as mediators that allow electrical testing of the sidewall wiring while isolating the probe from direct contact with the fragile side pads, thus preventing damage while maintaining testing capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the testing function into separate components: the side pads remain dedicated to their primary function of electrical connection, while separate testing elements are introduced for testing purposes. This segmentation allows the side pads to be protected from testing operations while the testing elements handle all probe interactions

Inventive Principle:

Principle #1Segmentation

2Length of moving object

If the driver chip is disposed on the back surface with sidewall wiring for narrow frame design, then frameless display is achieved, but the side pads become more vulnerable to damage during testing

Engineering Contradiction:

Improveframe widthVSAvoidside pad damage risk

Core Design Contradiction:

Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The testing elements act as intermediaries between the probe and the sidewall wiring system in narrow frame displays. By routing test signals through dedicated testing elements and their associated wirings rather than directly through side pads, the design enables sidewall wiring testing in compact frameless displays while protecting the side pads from probe-induced damage

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11552230B2Pixel array substrate

Publication Date: 2023.01.10 AU OPTRONICS CORP

AI summary

A pixel array substrate includes a base, pixel structures, first bonding pads, first wirings, and a first testing element. The pixel structures are disposed on an active area of a first surface of the base. The first bonding pads are disposed on a peripheral region of the first surface. Each of the first wirings is disposed on a corresponding first bonding pad, a first sidewall of the base, and a corresponding second bonding pad. The first testing element is disposed on the active area of the first surface and has a first testing line. The first testing line is electrically connected to at least one of the first bonding pads, and an end of the first testing line is substantially aligned with an edge of the base.