Top-Emission Display Pixel Stack to Avoid Sputtering Damage

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Solution Overview

Problem

Forming a light emitting unit and then forming an upper electrode using a sputtering method can damage the light emitting unit, leading to increased voltage requirements and reduced luminance in display devices.

Innovation Solution

Forming light-transmissive upper electrodes first, and then sequentially stacking a light emitting unit and a lower electrode, which is made of a metal material, to protect the light emitting unit during the electrode formation process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the light emitting unit is formed first and then the upper electrode is formed by sputtering, then the electrode can be formed on the light emitting unit, but the light emitting unit is damaged by sputtering, leading to increased voltage requirements and reduced luminance

Engineering Contradiction:

Improveease of manufactureVSAvoidreliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent inverts the conventional fabrication sequence by forming the upper electrode first and then forming the light emitting unit on top of it. This reversal eliminates the sputtering damage problem because the sputtering process is applied to form the electrode before the light emitting unit is deposited, so the light emitting unit is never exposed to damaging sputtering. This inversion resolves the contradiction by maintaining ease of manufacture through standard sputtering processes while improving reliability by preventing light emitting unit damage.

Inventive Principle:

Principle #13The other way round (Inversion)

2Device complexity

If the light emitting unit is formed first and then the upper electrode is formed by sputtering, then the electrode structure can be completed, but the damaged light emitting unit requires higher voltage, thereby hindering luminance increase

Engineering Contradiction:

Improvedevice complexityVSAvoidluminance

Core Design Contradiction:

Device complexityVSIllumination intensity

Solution Approach 1:

By inverting the formation sequence to create the upper electrode first and then the light emitting unit, the patent avoids sputtering-induced damage to the light emitting unit. This prevents the increase in voltage requirements that would otherwise be needed to compensate for damaged units, thereby maintaining the ability to achieve high luminance without increasing device complexity.

Inventive Principle:

Principle #13The other way round (Inversion)

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 reduces damage to the light emitting unit, allowing for increased luminance and improved performance of the display device.

Implementation Method 1

The light-transmissive upper electrodes are typically formed using, for example, a sputtering method.

Methodology Applied

Scientific EffectSputtering: Sputtering

Data Source

PatentUS12471440B2Display device, method for fabricating display device, and electronic instrument

Publication Date: 2025.11.11 SONY SEMICON SOLUTIONS CORP

AI summary

A display device is formed such that pixels that each include a light emitting element formed by stacking an upper electrode, a light emitting unit, and a lower electrode are arranged in a two-dimensional matrix. The light emitting elements are formed by forming the upper electrodes which are light-transmissive, and then sequentially stacking, onto the upper electrodes, the light emitting units and the lower electrode which is formed from a metal material.