OLED Driving Transistor Shield Layer for Light-Induced Leakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic light emitting display (OLED) devices face issues with current leakage and threshold voltage shift due to external light exposure, affecting the performance and reliability of the driving transistor.
Innovation Solution
A light shield layer is implemented to cover the lower, upper, and side surfaces of the semiconductor layer in the driving transistor, protecting it from external light and maintaining electrical stability by connecting the light shield layer to the second voltage line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the driving transistor is exposed to external light, then the OLED can be simpler in structure, but current leakage and threshold voltage shift occur
Solution Approach 1:
A light shield layer is introduced as an intermediary component between the external light environment and the driving transistor. This layer selectively blocks harmful light from reaching the semiconductor layer while allowing the device structure to remain relatively simple. The light shield layer acts as a mediator that protects the driving transistor from light-induced degradation without requiring complex structural modifications to the OLED.
Solution Approach 2:
The light shield layer is positioned to prevent light from reaching the driving transistor before the light can cause harmful effects. By placing the light shield layer adjacent to the semiconductor layer, the design proactively blocks light exposure in advance, preventing current leakage and threshold voltage shift before they occur, rather than attempting to correct these issues after they manifest.
2Reliability
If a light shield layer is added to protect the semiconductor layer, then electrical stability improves, but device complexity increases
Solution Approach 1:
The light shield layer is implemented as a thin film structure that can be integrated into the existing OLED architecture. This thin film approach provides effective light blocking while minimizing the additional complexity and volume added to the device. The flexible thin film structure allows for easy integration without requiring significant redesign of the overall device architecture.
Solution Approach 2:
The light shield layer serves multiple functions simultaneously: it blocks harmful light from reaching the driving transistor, maintains electrical stability, and can be integrated with existing device layers. By designing this component to perform multiple roles, the patent reduces the need for additional separate protective structures, thereby limiting the increase in overall device complexity.
3Object-affected harmful factors
If the light shield layer covers all surfaces of the semiconductor layer, then protection from external light is maximized, but manufacturing complexity increases
Solution Approach 1:
The light shield layer is positioned to cover specific critical surfaces of the semiconductor layer that are most vulnerable to light exposure, particularly the lower surface and side surfaces. Rather than uniformly covering all surfaces with equal thickness or material properties, the design applies light shielding selectively where it is most needed, optimizing protection effectiveness while simplifying the manufacturing process.
Solution Approach 2:
The patent implements light shielding on the lower surface and side surfaces of the semiconductor layer, which are the primary exposure paths for external light. This partial coverage approach provides sufficient protection against harmful light without requiring complete encapsulation of all surfaces, thereby reducing manufacturing complexity while maintaining adequate protection effectiveness.
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 light shield layer effectively prevents current leakage and threshold voltage shift, enhancing the driving stability and reliability of the OLED device while also configuring an auxiliary voltage line to address issues of IR drop and voltage drop, thereby achieving uniform brightness.
Implementation Method 1
a light shield layer covering a lower surface, an upper surface, and a side surface of the semiconductor layer, for protecting the driving transistor from external light
Data Source
AI summary
A light emitting display device includes a lower substrate, a driving transistor positioned on the lower substrate and including a semiconductor layer, a gate electrode, a source electrode, and a drain electrode, and a light shield layer covering a lower surface, an upper surface, and a side surface of the semiconductor layer, for protecting the driving transistor from external light.