Electrophoretic Display Contact Resistance Measurement
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Solution Overview
Problem
In electrophoretic display devices, it is challenging to directly measure the resistance value of the contact resistor of the common electrode, which is crucial for controlling images, as existing methods require indirect measurement and are not suitable for mass production due to complexity and instability.
Innovation Solution
The electrophoretic display device includes a first substrate with a common electrode, a second substrate with pixel electrodes and terminals, and connecting portions that electrically connect the terminals to different points of the common electrode, allowing direct measurement of the resistance value through conducting portions within a frame or microcapsules, simplifying the connection and enhancing structural reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If indirect measurement method is used for contact resistance, then measurement can be performed, but measurement precision and production stability deteriorate due to complexity and unsuitability for mass production
Solution Approach 1:
The patent extracts the measurement function from the complex indirect measurement process and implements it directly through the terminal structure. By providing a terminal that directly contacts the common electrode, the measurement process is simplified from multiple indirect steps to a single direct contact measurement, eliminating the need for complex calculation and intermediate measurements.
Solution Approach 2:
The patent introduces a terminal as an intermediary element between the measurement device and the common electrode. This terminal serves as a dedicated contact point that facilitates direct resistance measurement, acting as a mediator that simplifies the measurement interface without requiring modification of the common electrode itself.
2Reliability
If conventional through hole etching and sputtering method is used for forming contact, then contact structure is created, but manufacturing cost increases and ease of manufacture deteriorates due to complex multi-step process
Solution Approach 1:
The patent merges the terminal formation process with the existing electrode structure fabrication. The terminal is formed using the same conductive material and deposition processes as the ITO electrodes, combining multiple functions into a single structural element that serves both as electrode connection and measurement interface.
Solution Approach 2:
The terminal structure serves multiple functions: it acts as an electrical connection point for the common electrode, provides a measurement interface for contact resistance, and maintains structural integrity of the display panel. This multi-functionality eliminates the need for separate dedicated contact structures.
3Ease of manufacture
If conductive paste is used for forming contact instead of sputtering, then manufacturing cost is reduced, but contact resistance and electrical connection reliability worsen
Solution Approach 1:
The patent changes the material parameter from conductive paste to sputtered metal film, transitioning from a paste-based composition to a metallic film composition. This parameter change improves electrical conductivity and contact reliability while maintaining the simplified single-step formation process advantage.
Solution Approach 2:
The terminal structure uses composite material approach by combining ITO (indium tin oxide) with aluminum or other metals in a layered configuration. This composite structure leverages the transparency and conductivity of ITO with the low resistance and adhesion of metal layers, achieving both reliability and manufacturability.
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 enables straightforward measurement of the contact resistance of the common electrode, improving production stability and quality in mass production by simplifying the measurement process and ensuring reliable electric connections.
Implementation Method 1
performs display by utilizing the motion, under the influence of an electric field, of charged particles (migration particles) that migrate in a dispersion medium (solvent) that exists in the electrophoretic layer
Data Source
AI summary
An electrophoretic display device includes: a first substrate on which a common electrode is provided; a second substrate on which a pixel electrode and a plurality of terminals are provided; dispersion liquid that is provided between the first substrate and the second substrate and includes particles and a dispersion medium; and two or more connecting portions that electrically connect two or more terminals among the plurality of terminals respectively to different points of the common electrode.