Display Sub-Pixel Trench Isolation for Leakage Reduction

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Solution Overview

Problem

Existing display devices face challenges in achieving high reliability due to issues such as current leakage and color mixture between sub-pixels, which affect the overall performance and efficiency of the display.

Innovation Solution

The proposed display device incorporates a design with first and second sub-pixels, each featuring a pixel defining layer, emission components, intermediate layers, and electrodes. A trench is formed by recessing the pixel defining layer in the boundary area between the sub-pixels, with the first intermediate layer being interrupted over the trench and the second emission component completely covering it. This configuration enhances electrical insulation and reduces current leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a trench is formed by recessing the pixel defining layer in the boundary area between sub-pixels, then current leakage between sub-pixels is reduced and reliability is improved, but device complexity and manufacturing complexity increase

Engineering Contradiction:

Improvedisplay device reliabilityVSAvoidpixel structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The pixel defining layer is segmented by forming trenches in the boundary areas between sub-pixels, dividing the continuous layer into separate regions. This segmentation physically isolates adjacent sub-pixels, preventing current leakage while maintaining the functional integrity of each sub-pixel.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pixel defining layer is treated differently in different regions: in the boundary areas between sub-pixels, the layer is recessed to form trenches for electrical isolation, while in the emission areas, the layer remains intact to maintain optical functionality. This local differentiation resolves the contradiction by applying structural modification only where needed for reliability.

Inventive Principle:

Principle #3Local quality

2Reliability

If the first intermediate layer is interrupted over the trench and the second emission component completely covers it, then electrical insulation between sub-pixels is enhanced, but manufacturing precision requirements increase

Engineering Contradiction:

Improveelectrical insulation between sub-pixelsVSAvoidemission component coverage precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The trench is formed in the pixel defining layer before the emission components are deposited. This preliminary action creates a pre-defined isolation structure that guides subsequent material deposition, ensuring that the second emission component naturally covers the trench area while maintaining electrical insulation. The pre-formed trench acts as a template that simplifies the precision requirements for subsequent steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The second emission component is designed to completely cover the first intermediate layer over the trench, creating a nested structure where the emission component envelops the intermediate layer and trench. This nesting ensures that the trench's isolating function is preserved while being integrated within the overall emission structure, reducing the impact of manufacturing variations.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Reliability

If multiple emission components and intermediate layers are used with a trench structure, then color mixture between sub-pixels is prevented, but the number of manufacturing steps increases

Engineering Contradiction:

Improveprevention of color mixtureVSAvoidmanufacturing process simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The emission structure is segmented into multiple components (first emission component, second emission component, third emission component) separated by trenches and intermediate layers. This segmentation prevents color mixture by physically isolating the emission regions of adjacent sub-pixels while allowing each sub-pixel to maintain its full-color emission capability through the stacked emission components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using horizontal separation alone, the invention introduces vertical dimensionality with stacked emission components and intermediate layers. The trench structure extends vertically through the pixel defining layer, creating a three-dimensional isolation architecture that prevents color mixture more effectively than planar separation alone, while the vertical stacking allows efficient use of space.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS20250081751A1Display device, apparatus for manufacturing the same, and wearable electronic device

Publication Date: 2025.03.06 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a first sub-pixel, and a second sub-pixel located adjacent to the first sub-pixel. Each of the first and the second sub-pixels may include: a first electrode; a pixel defining layer on the first electrode; a first emission component on the pixel defining layer and configured to emit light; a first intermediate layer on the first emission component; a second emission component on the first intermediate layer and configured to emit light; and a second electrode on the second emission component. A trench may be formed by recessing at least a portion of the pixel defining layer in a boundary area between the first sub-pixel and the second sub-pixel. The first intermediate layer may be interrupted over the trench. The second emission component may completely cover the first intermediate layer over the trench.