OLED Light Absorbing Layer Protects Metal-Oxide Switching Transistors
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Solution Overview
Problem
Organic light emitting diode (OLED) display devices with metal-oxide-based switching transistors are prone to deterioration due to incident light, leading to changes in transistor characteristics, which affects the overall performance and reliability of the display.
Innovation Solution
Incorporating a light absorbing layer between the transistors and the organic insulating layer to block external light and prevent light emitted from the OLED from reflecting onto the metal-oxide-based semiconductor, thereby protecting the switching transistor and maintaining its characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a metal-oxide-based semiconductor is used as a switching transistor in an OLED display device, then the transistor can be fabricated at low temperature and integrated with silicon-based driving transistors, but the metal-oxide-based semiconductor deteriorates rapidly when exposed to incident light, causing changes in transistor characteristics
Solution Approach 1:
A light absorbing layer is introduced as an intermediary component between the external environment and the metal-oxide-based semiconductor switching transistor. This layer absorbs incident light before it reaches the semiconductor, preventing direct exposure and the associated deterioration. The light absorbing layer acts as a mediator that protects the switching transistor while allowing the device to maintain its low temperature fabrication advantage and electrical functionality.
2Illumination intensity
If the OLED structure allows light transmission for display functionality, then the display can emit and transmit light effectively, but incident light and reflected light reach the metal-oxide-based semiconductor, causing rapid deterioration
Solution Approach 1:
The light absorbing layer is selectively positioned only in regions where it can protect the metal-oxide-based semiconductor switching transistor without interfering with the overall light emission and transmission functionality of the OLED display. This localized approach ensures that the display maintains its illumination intensity and visual performance while the switching transistor region is protected from harmful light exposure.
Solution Approach 2:
The light absorbing layer serves as an intermediary that selectively blocks light in the transistor region while allowing light transmission in the display region. This mediator enables the coexistence of light transmission functionality and semiconductor protection by spatially differentiating the optical properties of different device regions.
3Reliability
If additional light absorbing layers are added to protect the metal-oxide-based semiconductor, then the semiconductor is protected from light-induced deterioration, but the device structure becomes more complex
Solution Approach 1:
The light absorbing layer is designed to serve multiple functions simultaneously: it protects the metal-oxide-based semiconductor from light-induced deterioration, maintains the low temperature fabrication process compatibility, and does not significantly interfere with the overall device performance. By integrating this protective layer into the existing device architecture, the patent achieves protection without proportionally increasing device complexity.
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 absorbing layer effectively absorbs about 90% of incident light, preventing deterioration of the metal-oxide-based semiconductor and maintaining the switching transistor's performance, ensuring stable OLED display operation.
Implementation Method 1
the light absorbing layer effectively absorbs about 90% of incident light, preventing deterioration of the metal-oxide-based semiconductor
Data Source
AI summary
An organic light emitting diode display device includes a substrate, a driving transistor, a switching transistor, a first light absorbing layer, an organic insulating layer, and a sub-pixel structure. The substrate includes a first region and a second region. The driving transistor is disposed in the first region on the substrate. The switching transistor is disposed in the second region on the substrate, and includes a metal-oxide-based semiconductor. The first light absorbing layer is disposed on the driving and switching transistors. The organic insulating layer is disposed directly on the first light absorbing layer. The sub-pixel structure is disposed on the organic insulating layer.