Insulated Substrate Electrode Structure for LED Connection Reliability

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Solution Overview

Problem

Conventional chip-type LEDs face issues with disconnection and bad connections between side surface electrodes and front/back surface electrodes over time, leading to malfunction and reliability concerns, especially in applications like liquid crystal televisions, where visual inspection of through holes is not possible and continuity inspection is challenging.

Innovation Solution

The electrode structure of the insulated substrate is designed with a plurality of connection electrodes extending through the substrate thickness, allowing for reliable electrical connection between front and back surface electrodes, and enabling inspection of bad connections by applying test voltage between separated plane patterns of the electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If side surface electrodes are formed in cutout parts to connect front and back surface electrodes, then electrical connection is achieved, but disconnection and bad connections occur over time leading to malfunction

Engineering Contradiction:

Improveconnection reliabilityVSAvoidservice life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The electrode structure is divided into multiple independent connection paths: front surface electrodes, back surface electrodes, and side surface electrodes forming distinct current paths. This segmentation allows individual failure of one path without complete system failure, improving reliability over time

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Redundant side surface electrodes are formed in advance within cutout parts of the insulated substrate to provide backup connection paths before disconnection occurs. This preemptive measure ensures that if one connection fails, alternative paths are already in place to maintain electrical continuity

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If through holes are formed in insulated substrate for connection electrodes, then electrical connection is enabled, but visual inspection of through holes is not possible making defect detection difficult

Engineering Contradiction:

Improveconnection integrityVSAvoiddefect detection

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

Cutout parts are formed in the insulated substrate to expose the side surface electrodes and connection interfaces. This extraction of the insulation material around the connection points enables visual inspection and defect detection of previously hidden through-hole connections

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The cutout parts act as intermediary structures that provide access to the internal connection electrodes. By creating these opening windows, the inspection process can indirectly observe the connection quality without requiring direct viewing of deep through holes

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If multiple side surface electrodes are formed in cutout parts, then connection redundancy is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveconnection redundancyVSAvoidelectrode structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Multiple side surface electrodes are merged into a unified formation process using screen printing or thick film deposition. The electrode pattern is applied simultaneously across multiple cutout parts in one manufacturing step, reducing process complexity despite increased structural redundancy

Inventive Principle:

Principle #5Merging (Combining)

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 enhances the reliability of LED devices by preventing disconnections and allowing for effective inspection of connections, thereby minimizing deterioration and ensuring high reliability of LED devices.

Implementation Method 1

inspection for a bad connection can be reliably performed between the front surface electrode or back surface electrode and any of the plurality of connection electrodes

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS8749263B2Semiconductor apparatus, inspection method thereof and electric device

Publication Date: 2014.06.10 SHARP FUKUYAMA LASER CO LTD

AI summary

A semiconductor apparatus according to the present invention with a semiconductor element implemented on an insulated substrate comprises: a substrate front surface electrode formed on a front surface side of the insulated substrate and connected with an element electrode of the semiconductor element; a substrate back surface electrode formed on a back surface side of the insulated substrate and electrically connected with the substrate front surface electrode; and a plurality of connection electrodes, extending in a thickness direction of the insulated substrate from one side to the other side of a front surface and a back surface thereof, for electrically connecting the substrate front surface electrode with the substrate back surface electrode, where the substrate front surface electrode or the substrate back surface electrode is formed to have a plane pattern separated for each of the plurality of connection electrodes.