Electrophoretic Display Driving Circuit Thermal Stress Protection
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Solution Overview
Problem
Conventional electro-phoretic display devices face issues with damage to the driving circuit due to uneven thermal stress and poor sealant quality, leading to reduced lifespan and yield rates.
Innovation Solution
The electro-phoretic display device design includes an electro-phoretic layer that covers both the active elements array and the driving circuit, acting as a protective layer, and the sealant is positioned at the edge of the driving circuit to minimize thermal stress and manufacturing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealant is disposed adjacent to the electro-phoretic display layer, then the sealant can seal the display layer, but the difference of thermal expansion coefficient between the sealant and the electro-phoretic layer will lead to thermal stress that may break the sealant or damage the driving circuit
Solution Approach 1:
The patent introduces an intermediate structure (the first substrate) between the sealant and the electro-phoretic display layer. This intermediate substrate acts as a buffer that can accommodate thermal expansion differences, reducing the thermal stress transmitted to both the sealant and the driving circuit while maintaining the sealing function.
Solution Approach 2:
The patent segments the sealing structure by positioning the sealant at the edge of the driving circuit rather than directly adjacent to the electro-phoretic display layer. This segmentation separates the sealing function from the display layer, reducing thermal stress concentration while maintaining effective sealing through the combined structure of substrate and sealant.
2Reliability
If the polymerization time is not accurately controlled during the process of forming sealant, then the obtained sealant can not effectually protect the driving circuit from corrosion by outer environments due to incomplete polymerization
Solution Approach 1:
The patent changes the material parameters of the sealant by selecting materials with appropriate polymerization characteristics that can achieve complete polymerization within a reasonable time frame. This parameter change ensures that the sealant effectively protects the driving circuit from environmental corrosion while maintaining manufacturing feasibility.
3Reliability
If the sealant layer is formed to protect the driving circuit, then the driving circuit is protected from environmental corrosion, but the sealant layer may break or damage the driving circuit due to uneven thermal stress
Solution Approach 1:
The first substrate serves as an intermediary between the sealant layer and the driving circuit. This intermediate structure absorbs and distributes thermal stress, preventing direct transmission of uneven thermal stress to the driving circuit while maintaining the protective sealing function.
Solution Approach 2:
The patent designs the sealing structure with built-in stress distribution characteristics that cushion against thermal stress before it can damage the driving circuit. The structural arrangement and material selection provide preliminary protection against thermal expansion differences, preventing sealant breakage and circuit damage.
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
This design enhances the lifespan and yield rate of the electro-phoretic display device by preventing damage from thermal stress and improving the quality of the sealant formation.
Implementation Method 1
electro-phoretic display devices (EPD), which utilize electric field to control the distribution of charged particles so as to change the reflectivity of a display area, thereby displaying image
Implementation Method 2
the polymerization time is not accurately controlled during the process of forming sealant 170, then the obtained sealant 170 can not effectually protect the driving circuit 130 from corrosion by outer environments due to incomplete polymerization
Data Source
AI summary
An electro-phoretic display device includes a first substrate, an active elements array, a driving circuit, a conductive flexible board, an electro-phoretic layer and a second substrate. The first substrate has a first surface defining a display area and a circuit area, and a second surface. The active elements array is disposed within the display area and the driving circuit is disposed within the circuit area and electrically connected to the active elements array. The conductive flexible board is partially disposed at the first substrate and electrically connected to the driving circuit. The electro-phoretic layer and the second substrate are sequentially disposed on the active elements array and the driving circuit. A fabricating method of electro-phoretic display device is also disclosed.