Display Device Dual-Layer Bonding Thermal Stability
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Solution Overview
Problem
Conventional liquid crystal display devices with integrated touch panels face issues of yellowing unevenness due to gaps between the array substrate and the counter substrate, which are difficult to fill with existing bonding materials, leading to visibility issues and poor manufacturability.
Innovation Solution
A display device configuration featuring a primary bonding portion of translucent synthetic resin covering the display area and a secondary bonding portion of high-viscosity ultraviolet curable resin in a columnar shape, applied at specific points or lines to bond the non-opposed peripheral areas, ensuring effective bonding and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If low-viscosity UV curable resin is used to fill the gap, then the gap can be filled, but the filled portion is thermally stable yet insufficient in stiffness, causing yellowing unevenness
Solution Approach 1:
The patent uses a composite bonding structure combining translucent synthetic resin (for thermal stability and gap filling) with UV curable resin (for stiffness and structural support). This composite approach allows the filled portion to simultaneously achieve both thermal stability and sufficient stiffness, preventing yellowing unevenness while maintaining structural integrity.
2Manufacturing precision
If UV curable resin is stretched to the periphery of the driver IC to fill the gap, then the gap can be filled, but it is not easy to adjust the amount and position of application
Solution Approach 1:
The bonding structure is segmented into two distinct parts: a primary bonding portion using translucent synthetic resin for general gap filling and thermal stability, and a secondary bonding portion using UV curable resin for localized stiffness reinforcement. This segmentation allows each material to be applied in optimized amounts and positions, improving manufacturing control while achieving complete gap filling.
3Strength
If silicon is used to fill the gap, then stiffness can be ensured and yellowing unevenness at room temperature can be reduced, but yellowing unevenness due to thermal expansion occurs at increased temperature
Solution Approach 1:
The patent changes the material parameter from silicon (high stiffness but high thermal expansion) to a combination of translucent synthetic resin (low thermal expansion) and UV curable resin (controlled stiffness). This parameter change maintains sufficient stiffness while achieving thermal stability, preventing yellowing unevenness at both room temperature and elevated temperatures.
4Manufacturing precision
If the gap is completely filled with bonding material, then yellowing unevenness can be prevented, but the complexity of controlling material amount and position increases
Solution Approach 1:
The patent applies different bonding materials with different properties to different locations: translucent synthetic resin is used for the main bonding portion requiring thermal stability and gap filling, while UV curable resin is used for the secondary bonding portion requiring localized stiffness. This local quality differentiation achieves complete gap filling and display uniformity while simplifying overall material application control.
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 configuration reduces yellowing unevenness and improves manufacturability by allowing precise control of adhesive application and thermal expansion, maintaining display quality across varying temperatures.
Implementation Method 1
a bonding portion composed of ultraviolet curable resin and provided to bond together the counter substrate side and the touch panel side
Data Source
AI summary
According to one embodiment, provided is a display device with an improved manufacturability which is capable of preventing a decrease in the display quality due to a change in the gap between an array substrate and a counter substrate caused by a temperature change. The primary bonding portion is composed of translucent synthetic resin and provided to bond together the counter substrate side and a touch panel side in a manner covering at least a display area. The secondary bonding portion is provided in a columnar shape through curing of adhesive being ultraviolet curable liquid resin with a viscosity higher than that of the synthetic resin of the primary bonding portion, the secondary bonding portion bonding together the non-opposed portion side and the touch panel side.