Touch Panel Floating Units for Parasitic Capacitance Reduction
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Solution Overview
Problem
In-cell touch-type organic light-emitting display devices face issues with retransmission phenomena due to increased parasitic capacitance, leading to reduced touch sensitivity and malfunctions, and metal mesh patterns used to enhance flexibility result in reduced luminance and poor color viewing angle characteristics.
Innovation Solution
A touch panel design featuring intersecting first and second electrodes with floating units made of transparent conductive materials, connected via bridges and segment electrodes, which reduce parasitic capacitance and minimize visibility of metal mesh patterns, thereby enhancing luminance and color viewing angle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the thickness of the touch panel is reduced, then the device becomes thinner and more portable, but parasitic capacitance between touch electrodes and user's finger increases causing retransmission phenomena
Solution Approach 1:
A floating electrode layer is introduced as an intermediary between the touch electrodes and the user's finger. This floating electrode acts as a mediator that reduces the direct parasitic capacitance coupling while still allowing touch sensing functionality to operate, thereby resolving the retransmission problem caused by reduced panel thickness.
Solution Approach 2:
The harmful parasitic capacitance effect is extracted and isolated by creating a separate floating electrode layer that is electrically disconnected from the main touch electrode circuitry. This separates the problematic capacitance coupling from the functional touch sensing path.
2Ease of manufacture
If a metal mesh pattern is used for touch electrodes, then flexibility and low resistance are improved, but the mesh pattern becomes visible reducing overall luminance and color viewing angle characteristics
Solution Approach 1:
The touch electrode structure uses a composite design combining metal mesh pattern for electrical functionality with a transparent overlay layer for optical performance. This composite structure allows the metal mesh to provide flexibility and low resistance while the transparent layer masks the mesh visibility to maintain high luminance and color viewing angle characteristics.
Solution Approach 2:
The metal mesh pattern is strategically positioned and designed with specific geometries to concentrate electrical functionality in certain areas while minimizing optical interference in viewing areas. Different regions of the touch electrode have different properties optimized for their specific functions.
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
The design effectively reduces retransmission phenomena, improves touch sensitivity, and maintains high luminance and color viewing angle performance even at varying angles, while allowing for flexible display applications.
Implementation Method 1
parasitic capacitance between the first and second touch electrodes and the user's finger is increased
Data Source
AI summary
Disclosed herein are a touch panel and a touch-panel-integrated organic light-emitting display device that are capable of solving a retransmission problem while exhibiting excellent luminance and color viewing angle characteristics. The touch panel includes a plurality of first and second electrodes disposed on a substrate so as to intersect each other. Each first electrode includes a first touch electrode, the first touch electrode including a first metal mesh pattern having a lattice structure formed by a plurality of first and second line electrodes intersecting each other and a first floating unit disposed in the central part of the first metal mesh pattern, the first floating unit being electrically isolated from the first metal mesh pattern, the first floating unit being made of a transparent conductive material. Each second electrode includes a second touch electrode, the second touch electrode including a second metal mesh pattern formed by a plurality of third and fourth line electrodes intersecting each other in a lattice structure and a second floating unit disposed in the central part of the second metal mesh pattern, the second floating unit being electrically isolated from the second metal mesh pattern, the second floating unit being made of a transparent conductive material.