Display Substrate Detection Capacitor for Organic Layer Overflow

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Solution Overview

Problem

Existing OLED display substrates are vulnerable to water and oxygen intrusion due to organic layer overflow, which complicates detection and leads to damage, as the encapsulation layers are sensitive to processing technologies and screen shapes, causing external invasion through overflow channels.

Innovation Solution

A display substrate with a detection capacitor comprising a first and second electrode plate made of the same material and layer, positioned on either side of the encapsulation layer, which detects organic layer overflow by measuring capacitance changes, and includes blocking structures to reduce overflow likelihood, with an encapsulation layer of sequentially stacked inorganic and organic layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the organic layer is formed using conventional processing technologies, then the display substrate can be manufactured, but the organic layer may extend beyond the original position and overflow to the peripheral region, creating channels for water and oxygen invasion

Engineering Contradiction:
Improveorganic layer formation processVSAvoidorganic layer positioning accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

A detection capacitor is constructed before the organic layer formation process. This capacitor includes a first electrode plate on the base substrate and a second electrode plate positioned above the encapsulation layer, allowing overflow detection capability to be established in advance before any overflow can occur

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The detection capacitor acts as an intermediary detection mechanism between the organic layer and the sensitive display components. By measuring capacitance changes in this intermediate structure, overflow can be detected indirectly through the dielectric properties of the encapsulation layers without directly contacting the organic material

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the encapsulation layer is made sensitive to processing technologies and screen shapes, then better encapsulation can be achieved, but overflow channels are more easily formed due to material extension beyond original positions

Engineering Contradiction:
Improveencapsulation protection capabilityVSAvoidwater and oxygen intrusion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The detection capacitor provides real-time feedback on encapsulation quality by measuring capacitance values. When the organic layer overflows and alters the dielectric environment, the capacitance changes, providing immediate feedback that allows for quality control and potential process adjustments

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical detection methods (such as visual inspection or physical sampling) with an electrical field-based capacitance measurement system. This substitution enables non-contact, automated detection of overflow conditions through changes in the electrical properties of the encapsulation structure

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If conventional detection methods are used to detect water and oxygen invasion, then the display substrate can be monitored, but the detection process becomes complicated and time-consuming

Engineering Contradiction:
Improvewater and oxygen invasion detectionVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the detection function from complex post-manufacturing testing systems and integrates it directly into the encapsulation structure itself through the detection capacitor. This extraction simplifies the overall detection system by making the detection capability an inherent part of the device rather than an external add-on

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The detection capacitor serves multiple functions: it acts as part of the encapsulation structure, provides overflow detection capability, and can potentially serve as a quality control sensor during manufacturing. This multi-functionality reduces the need for separate detection systems and simplifies the overall device architecture

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If the organic layer material is applied generously to ensure complete coverage, then better encapsulation is achieved, but overflow to the peripheral region increases, creating invasion channels

Engineering Contradiction:
Improveencapsulation coverageVSAvoidorganic layer overflow
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The detection capacitor is constructed with electrode plates positioned to detect overflow before it reaches critical levels. The first electrode plate is on the base substrate and the second electrode plate is above the encapsulation layer, creating a detection zone that monitors the organic layer boundaries in advance

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent monitors changes in dielectric parameters (capacitance) of the encapsulation structure to detect overflow. By measuring capacitance variations, the system can detect when the organic layer extends beyond its intended boundaries, allowing for parameter-based quality control of the encapsulation process

Inventive Principle:
Principle #35Parameter changes

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

The solution effectively and quickly detects organic layer overflow and reduces the risk of water and oxygen intrusion, ensuring the display substrate's integrity by simplifying the detection process and enhancing encapsulation quality through capacitance measurement and blocking structures.

Implementation Method 1

a detection capacitor 130 located in a peripheral area of the display substrate. A first electrode plate 131 of the detection capacitor 130 is formed on a side of the encapsulation layer 120 close to the base substrate, and a second electrode plate 132 of the detection capacitor 130 is formed on a side of the encapsulation layer 120 far away from the base substrate

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3846213B1Display substrate and manufacturing method thereof, display panel and display apparatus
Publication Date: 2024.02.14 BOE TECHNOLOGY GROUP CO LTD
  • EP3846213B1 patent drawingFigure 1~3
  • EP3846213B1 patent drawingFigure 4~5
  • EP3846213B1 patent drawingFigure 6

AI summary

A display substrate and a method for manufacturing the same, a display panel and a display device are provided. The display substrate includes a base substrate, a display component on the base substrate, and an encapsulation layer covering the display component, where the encapsulation layer includes an organic layer and an inorganic layer that are stacked alternately. A detection capacitor is further provided in a peripheral region of the display substrate. The detection capacitor includes a first electrode plate on a side of the encapsulation layer close to the base substrate, and a second electrode plate on a side of the encapsulation layer away from the base substrate.