LED Drive Backplane Stress Relief Structure for TFT Stability
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Solution Overview
Problem
The transfer process for bonding micro LEDs onto drive backplanes affects the characteristics of thin-film transistors, leading to increased off-state current and subthreshold swing, which impacts the performance of micro LED drive backplanes due to stress on the active layer.
Innovation Solution
A drive backplane with a stress relief structure comprising metal strips on either side of the gate, which reduces stress concentration on the active layer, stabilizing the characteristics of the thin-film transistors by redistributing stress and minimizing changes in interface and trap states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the transfer process is used to bond micro LEDs onto drive backplanes, then the micro LED display performance is improved with higher illuminance and better luminous efficiency, but the thin-film transistor characteristics deteriorate due to stress on the active layer
Solution Approach 1:
The stress relief structure acts as an intermediary element between the micro LED and the thin-film transistor. It absorbs and redistributes the stress generated during the transfer process, preventing direct transmission of mechanical stress to the active layer. This mediator structure allows the micro LED to be firmly bonded while protecting the TFT characteristics from degradation.
Solution Approach 2:
The stress relief structure is designed in advance to cushion against the stress that will be generated during the transfer process. By pre-positioning this stress-absorbing structure, the patent prevents stress concentration on the active layer before the bonding process occurs, thereby maintaining TFT reliability while enabling micro LED integration.
2Loss of energy
If the transfer process is used to bond micro LEDs onto drive backplanes, then the luminous efficiency is improved, but the off-state current increases due to stress on the active layer
Solution Approach 1:
The stress relief structure serves as a mediator that isolates the active layer from stress-induced changes. By absorbing the mechanical stress during transfer, it prevents stress from altering the semiconductor properties of the active layer, thereby suppressing the increase in off-state current while maintaining high luminous efficiency.
Solution Approach 2:
The patent converts the potentially harmful stress generated during transfer into a beneficial effect by using it to activate the stress relief structure. This structure then redistributes the stress in a controlled manner, transforming what would be a harmful stress concentration into a protective mechanism that maintains low off-state current.
3Use of energy by moving object
If the transfer process is used to bond micro LEDs onto drive backplanes, then the power consumption is reduced, but the subthreshold swing increases due to stress on the active layer
Solution Approach 1:
The stress relief structure acts as an intermediary that protects the active layer from stress-induced degradation of electrical characteristics. By absorbing and redistributing stress, it prevents stress from altering the subthreshold swing parameter, thereby maintaining precise TFT control while enabling energy-efficient micro LED operation.
Data Source
AI summary
Provided is a drive backplane for a light-emitting diode, including a substrate and a drive structure on the substrate, the drive structure including a thin-film transistor and a stress relief structure; wherein the thin-film transistor includes an active layer on the substrate, a first insulation layer covering the active layer, and a first gate on the first insulation layer; and the stress relief structure is on the first insulation layer and includes a first metal strip on a first side of the first gate and a second metal strip on a second side of the first gate, wherein the first side is opposite to the second side. A method for preparing the light-emitting diode and a display device are further disclosed.