Hydrogen Absorbing Layer for Light Emitting Display Apparatus
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Solution Overview
Problem
The residual hydrogen generated during the formation of the passivation layer in light emitting display apparatuses can diffuse into the thin film transistors, degrading their performance and leading to issues like threshold voltage shifts, increased mobility, and luminance irregularities.
Innovation Solution
Incorporating a hydrogen absorbing layer with an inorganic material having a mass percentage of 0.08% to 50% in the light emitting display apparatus, which absorbs the residual hydrogen from the passivation layer, thereby preventing its diffusion into the thin film transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passivation layer is formed using CVD method with silane and ammonia, then the light emitting diode is protected from moisture and oxygen, but hydrogen is generated and diffused into the thin film transistor causing performance degradation
Solution Approach 1:
A hydrogen absorbing layer is introduced as an intermediary component between the passivation layer and the thin film transistor. This layer absorbs the hydrogen generated during CVD processing, preventing it from diffusing into the semiconductor layer and degrading the TFT performance while maintaining the protective function of the passivation layer.
Solution Approach 2:
The hydrogen that would normally be a harmful byproduct causing TFT degradation is converted into a beneficial absorbed state within the hydrogen absorbing layer. The layer captures and retains the hydrogen, transforming it from a harmful diffusing species into a contained element that no longer adversely affects device performance.
2Stability of the object's composition
If the passivation layer is formed to protect the light emitting diode, then moisture and oxygen penetration is prevented, but the residual hydrogen degrades the thin film transistor characteristic
Solution Approach 1:
The protective structure is segmented into multiple functional layers: the passivation layer for moisture and oxygen barrier, and a separate hydrogen absorbing layer for capturing hydrogen. This segmentation allows each layer to perform its specific function optimally without interfering with the other, maintaining both protection and TFT characteristic precision.
3Reliability
If hydrogen is absorbed by the semiconductor layer, then the threshold voltage is shifted and mobility increases, but the switching characteristic of the thin film transistor is degraded
Solution Approach 1:
The hydrogen absorbing layer performs preliminary anti-action by capturing hydrogen before it can diffuse into the semiconductor layer. This preventive measure stops the hydrogen from causing threshold voltage shifts and mobility changes that would degrade the switching characteristic, maintaining reliable TFT operation.
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 hydrogen absorbing layer effectively suppresses the performance degradation of the thin film transistors by removing residual hydrogen, reducing the occurrence of bright spots and luminance irregularities, and maintaining normal threshold voltage ranges.
Implementation Method 1
a hydrogen absorbing layer on the light emitting diode and includes an inorganic material having a mass percentage of 0.08% to 50%
Data Source
AI summary
A light emitting display apparatus includes a passivation layer on a thin film transistor, a light emitting diode on the passivation layer, the light emitting diode having an anode, a light emitting layer on the anode, and a cathode on the light emitting layer, and a hydrogen absorbing layer on the light emitting diode, the hydrogen absorbing layer including an inorganic material having a mass percentage of 0.08% to 50%.