Electrowetting Display Dam Member With Sealable Openings
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Solution Overview
Problem
Electrowetting display devices face issues with non-uniform cell gaps and potential sealant bursting due to excess internal pressure during assembly, leading to bulging and adhesive strength problems.
Innovation Solution
Incorporating a dam member with sealable openings around the perimeter of the display area to discharge excess wetting fluid, ensuring uniform cell gaps and enhanced adhesive strength by increasing the adhesion surface area between substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If excess wetting fluid is applied during assembly to ensure complete filling, then the filling completeness is improved, but the internal pressure increases causing sealant bursting and non-uniform cell gaps
Solution Approach 1:
The patent extracts the excess wetting fluid from the system by providing controlled discharge paths (openings) in the dam member structure. This allows the beneficial complete filling to occur while removing the harmful excess fluid that would otherwise cause pressure buildup, sealant bursting, and cell gap non-uniformity.
Solution Approach 2:
The dam member incorporates openings that function as controlled porous structures, allowing selective discharge of excess fluid while maintaining the structural integrity needed to contain the necessary fluid volume. This enables pressure regulation through controlled fluid egress paths.
2Strength
If high combining pressure is applied during substrate assembly to ensure bonding, then the adhesive strength is improved, but the cell gap uniformity deteriorates due to bulging
Solution Approach 1:
By providing discharge paths for excess wetting fluid, the patent eliminates the source of pressure-induced bulging. This allows high combining pressure to be applied for strong bonding without the harmful side effect of cell gap non-uniformity, as the excess fluid can escape through the controlled openings rather than causing bulging.
3Quantity of substance
If the dam member is made completely sealed to prevent fluid loss, then the fluid retention is improved, but the pressure buildup causes sealant bursting
Solution Approach 1:
The dam member structure implements local quality differentiation by having sealed portions for fluid retention and localized openings for pressure relief. This selective sealing approach maintains fluid containment where needed while providing controlled discharge paths to prevent pressure buildup and sealant failure.
Solution Approach 2:
The dam member incorporates controlled porous structures (openings) that allow selective fluid discharge. This creates a semi-permeable barrier that retains necessary fluid volume while permitting excess fluid to escape, preventing pressure-induced sealant bursting.
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
Prevents sealant bursting and maintains uniform cell gaps across the display area, enhancing the structural integrity and reliability of the electrowetting display device.
Implementation Method 1
an undesired bursting of a sealant which combines the first substrate with the second substrate may occur if there an excess of internal pressure in the filling space during the process of bonding together (combining) the substrates
Implementation Method 2
an undesired bursting of a sealant which combines the first substrate with the second substrate
Implementation Method 3
When an appropriate voltage is applied between a respective pixel electrode and the common electrode, a normal surface tension state of the polar (e.g., hydrophillic) upper fluid is overcome and it is displaced
Implementation Method 4
a wall pattern surrounding a pixel electrode and disposed in a display area of the device... a dam member disposed in a peripheral area surrounding the display area
Data Source
AI summary
An electrowetting display device includes a first substrate comprising a wall pattern surrounding a pixel electrode disposed in a display area of the first substrate, a spaced apart second substrate comprising a common electrode and a dam member disposed in a peripheral area surrounding the display area. The dam member has sealable openings (a.k.a. sealable dam spillways) through which there is discharged an excess portion of an excessively supplied wetting layer, the discharge of the excess occurring while the first and second substrates are brought together about top and bottom portions of a sealing ring that seals them together.