Touch Panel Electrode Layout for Optical Uniformity and Lower Cost
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Solution Overview
Problem
Conventional static capacitance coupling type touch panels suffer from optical characteristic deterioration due to noticeable electrode patterns caused by color differences and inefficient process and material usage, leading to increased costs in display devices.
Innovation Solution
A touch panel structure where first electrodes have a first portion on a different layer from second electrodes, connected via a contact hole in an insulating film, with first portions formed using conductive metal for lower resistance and second portions using transparent conductive material, and wirings integrated with first portions to reduce redundant material and process costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrodes are formed on different electrically conductive layers via an insulating film, then touch panel functionality is achieved, but color differences and distortion cause noticeable electrode patterns that deteriorate optical characteristics
Solution Approach 1:
The patent applies local quality by making different portions of the first electrode have different properties: the first portion uses a transparent conductive material matching the second electrode for optical consistency, while the second portion uses a different conductive material for electrical connection, thus resolving the contradiction between functionality and optical quality
Solution Approach 2:
The patent resolves the layering conflict by changing the dimensional arrangement - instead of having both electrodes on different layers causing optical issues, the first electrode is split into portions on different layers, with the first portion on the same layer as the second electrode to eliminate color differences and visible patterns
2Reliability
If first portions of electrodes are formed on different layers connected via contact holes, then electrical connectivity is achieved, but redundant material and process steps increase production costs
Solution Approach 1:
The patent merges the first portion of the first electrode with the wiring structure by forming them simultaneously in the same process step, eliminating redundant material deposition and patterning steps, thus reducing production costs while maintaining electrical connectivity
Solution Approach 2:
The patent makes the first portion of the first electrode serve multiple functions: it acts as both an electrode for touch detection and as a wiring for electrical connection, eliminating the need for separate wiring structures and reducing manufacturing 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 structure minimizes visible electrode patterns, maintains optical characteristics, and reduces production costs by eliminating redundant material and process steps, resulting in a more cost-effective touch panel-equipped display device.
Implementation Method 1
the insulating film and a protective film formed on an electrode on the upper layer are distorted due to the electrode on the upper layer
Implementation Method 2
as the optical path length for reflected light is different between the lower layer and the upper layer, a color difference is caused between an electrode on the lower layer
Data Source
AI summary
A touch panel-equipped display device includes an electrostatic capacitance type touch panel and an organic EL display panel. The touch panel includes a transparent insulating substrate, a plurality of first electrodes formed on the substrate and extending at least in a first direction, a plurality of second electrodes formed on the substrate and extending at least in the second direction that intersects the first direction, and a plurality of wirings provided in a peripheral area of the substrate. The plurality of wirings are electrically connected to the first electrodes and the second electrodes respectively. The first electrodes include a first portion and a second portion. The second portion is formed on the same layer as that on which the second electrodes are formed. The first portion is formed on a layer different from that on which the second portion and the second electrodes are formed.