Plastic Substrate Direct Bonding Without Coupling Agent
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Solution Overview
Problem
Plastic substrates in liquid crystal displays are prone to deformation and separation due to heat or light curing of coupling agents, resulting in reduced reliability and manufacturing challenges.
Innovation Solution
Applying heat and pressure directly to the plastic substrates in the peripheral area to bond them without an additional coupling member, using a substrate bonding apparatus with a pressing member and heating element to melt and secure the substrates together.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a coupling agent is used to bond the two plastic substrates, then the substrates can be coupled together, but the substrates are susceptible to deformation by heat or light and the coupling force is lower compared to glass substrates
Solution Approach 1:
The patent removes the coupling agent from the bonding process entirely. Instead of using a separate coupling agent layer between substrates, the invention directly bonds the plastic substrates together through heat and pressure application, eliminating the source of deformation and coupling weakness
Solution Approach 2:
The patent replaces the chemical bonding mechanism (coupling agent curing through heat or light) with a direct thermal-mechanical bonding process. Heat and pressure are applied directly to the substrate interface to achieve bonding, substituting the chemical system with a physical mechanism that avoids coupling agent-related deformation
2Strength
If heat or light is applied to cure the coupling agent, then the two substrates can be strongly coupled, but the plastic substrates are susceptible to deformation by heat or light
Solution Approach 1:
The patent extracts and removes the coupling agent from the system, eliminating the need for heat or light curing processes that cause plastic substrate deformation. The bonding is achieved through direct thermal-mechanical contact without intermediate chemical agents
Solution Approach 2:
The patent changes the bonding parameters by applying controlled heat and pressure directly at the substrate interface rather than using high-temperature or high-intensity light curing. This parameter modification allows bonding while minimizing thermal deformation of the plastic substrates
3Ease of manufacture
If a coupling agent is interposed between the two substrates, then the liquid crystal can be sealed, but the manufacturing process becomes more complex and reliability deteriorates
Solution Approach 1:
The patent removes the coupling agent from the manufacturing process, simplifying the process by eliminating the steps of applying, positioning, and curing the coupling agent. This extraction also eliminates reliability issues associated with coupling agent performance
Solution Approach 2:
The patent merges the sealing and bonding functions into a single direct substrate-to-substrate bonding process. The peripheral area bonding simultaneously achieves both mechanical coupling and liquid crystal sealing, eliminating the need for separate coupling agent application
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 method enhances the reliability of the display device by eliminating the need for a coupling agent, preventing substrate deformation and improving the bonding strength between plastic substrates, thus simplifying the manufacturing process and maintaining the display's integrity.
Implementation Method 1
The heating member supplies heat to the pressing member
Implementation Method 2
Heat and pressure are applied to at least one of the first plastic substrate and the second plastic substrate at a location corresponding to the peripheral area, so that the first and second plastic substrates are melted by the heat and pressure
Implementation Method 3
Heat and pressure are applied to at least one of the first plastic substrate and the second plastic substrate at a location corresponding to the peripheral area
Implementation Method 4
The driven shaft is connected to the pressing member to move the pressing member
Data Source
AI summary
A display device includes first and second plastic substrates. The first substrate is directly bonded to the second plastic substrate by heat and pressure. When the display device is manufactured, a process of forming a coupling member interposed between the first and second plastic substrates may be omitted, thereby preventing deterioration of reliability of the display device due to the coupling member.