Electrophoretic Display Storage Capacitance Structure
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Solution Overview
Problem
Electrophoretic display devices require storage capacitance to maintain display states, but existing structures face challenges in enhancing capacitance while preventing short-circuits and moisture-related corrosion, which affects reliability and display quality.
Innovation Solution
The use of an inorganic insulating film structure with a metal film having a forward tapered end portion and a capacitor insulating film, which increases storage capacitance and prevents short-circuits, along with a sealing member to block moisture, improves adhesion and reliability, and enhances display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a storage capacitance electrode is formed from a light-shielding metal film, a protective film and a pixel electrode, then storage capacitance is provided, but the structure is complex and adhesion is insufficient
Solution Approach 1:
The patent combines the storage capacitance electrode and capacitor insulating film into an integrated structure where the capacitor insulating film serves dual purposes as both insulation and adhesion enhancement layer, reducing the number of separate components while improving reliability
Solution Approach 2:
The patent employs composite material structures with multiple layers including inorganic insulating films, organic insulating films, and metal films with specific compositions to achieve both electrical insulation and mechanical adhesion in a single integrated system
2Reliability
If voltage is applied to maintain display state, then display quality is maintained, but energy consumption increases
Solution Approach 1:
The patent incorporates storage capacitance structures that pre-store electrical energy in the form of charged capacitor electrodes, providing a reservoir that maintains display state without requiring continuous external power, thus cushioning against energy consumption needs
Solution Approach 2:
The display device uses its own integrated storage capacitance electrodes to self-maintain the display state through stored charge, eliminating the need for external power maintenance and enabling the device to service itself
3Reliability
If microcapsules are arranged between substrates, then electrophoretic display function is achieved, but moisture penetration causes corrosion
Solution Approach 1:
The patent employs multiple thin film barriers including capacitor insulating films and protective films that form flexible yet effective moisture barriers, preventing moisture penetration while maintaining the electrophoretic display structure
Solution Approach 2:
The patent uses composite film structures combining different material properties (inorganic and organic layers) to create multi-functional barriers that simultaneously provide electrical insulation, mechanical protection, and moisture resistance
4Reliability
If storage capacitance is increased, then voltage holding capability is improved, but device complexity increases
Solution Approach 1:
The patent merges the capacitor structure with the existing pixel electrode and protective film layers, integrating storage capacitance functionality into the existing display structure rather than adding separate components, thus improving voltage holding without proportionally increasing complexity
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 enhances storage capacitance, prevents short-circuits and corrosion, and improves display reliability and quality by using inorganic insulating films and a sealing member to block moisture, resulting in a more reliable and efficient electrophoretic display device.
Implementation Method 1
Such a storage capacitance is constituted by, for example, a storage capacitance electrode formed form a light-shielding metal film, a protective film and a pixel electrode
Implementation Method 2
an electrophoretic display device having a structure in which an electrophoretic element in which microcapsules are arranged is held between an element substrate and a counter-substrate
Implementation Method 3
a sealing member to block moisture
Data Source
AI summary
According to one embodiment, a display device includes a switching element including a source electrode and a drain electrode, an inorganic insulating film in contact with the source electrode and the drain electrode, a metal film in contact with the inorganic insulating film and including an opening in a position superimposed on the drain electrode, a capacitor insulating film covering the metal film, an pixel electrode located on the capacitor insulating film and electrically connected to the drain electrode, an electrophoretic element located on the pixel electrode and a common electrode located on the electrophoretic element, and the metal film includes a forward tapered end portion in the opening.