Silver-Inclusive Transparent Conductive Layer for Capacitive Touch Panels
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Solution Overview
Problem
Existing projected capacitive touch panels require complex and costly manufacturing processes involving multiple thin film layers and photolithography steps, leading to high production costs and inefficiencies, particularly due to the use of indium tin oxide (ITO) which has high sheet resistance and limited transparency.
Innovation Solution
A projected capacitive touch panel with a silver-inclusive transparent conductive layer sandwiched between dielectric layers, which can be patterned into electrodes using fewer photolithography steps, reducing production costs and improving conductivity and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If indium tin oxide (ITO) is used as the transparent conductive coating, then the touch panel achieves electrical conductivity, but the sheet resistance is high and transparency is limited
Solution Approach 1:
The patent replaces the single-material ITO coating with a composite structure consisting of multiple thin film layers including metal layers (such as aluminum, silver, or copper), insulating layers (such as silicon nitride, silicon oxide, or tungsten oxide), and transparent conductive oxide layers. This composite structure achieves lower sheet resistance while maintaining high transparency, resolving the contradiction between electrical conductivity and transparency.
2Reliability
If multiple thin film layers are deposited to improve conductivity and transparency, then the electrical performance improves, but the manufacturing process complexity and cost increase
Solution Approach 1:
The patent segments the transparent conductive coating into multiple functional layers, each with specific thicknesses and materials (metal layers, insulating layers, transparent conductive oxide layers). This segmentation allows optimization of electrical and optical properties while enabling systematic manufacturing processes with controlled deposition parameters for each layer.
Solution Approach 2:
The patent optimizes the thickness parameters of each layer (metal layer thickness of 5-50 nm, insulating layer thickness of 50-200 nm, transparent conductive oxide layer thickness of 10-100 nm) to achieve the desired balance between conductivity and transparency. By controlling these parameters, the patent reduces sheet resistance while maintaining manufacturing feasibility.
3Reliability
If thicker conductive layers are used to reduce sheet resistance, then electrical conductivity improves, but transparency decreases
Solution Approach 1:
The patent uses a composite multi-layer structure where thin metal layers (5-50 nm) provide high conductivity without significantly blocking light. The insulating layers (50-200 nm) and transparent conductive oxide layers (10-100 nm) complement the metal layers to achieve low sheet resistance while maintaining high transparency, avoiding the need for thick single layers that would block light.
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 silver-inclusive transparent conductive layer reduces production costs and enables the creation of larger, more efficient touch panels with lower sheet resistance and higher transparency, supporting multi-touch capabilities and larger display applications.
Implementation Method 1
A capacitive touch panel includes an insulator such as glass, coated with a conductive coating. As the human body is also an electrical conductor, touching the surface of the panel results in a distortion of the panel's electrostatic field, measurable as a change in capacitance.
Implementation Method 2
at least one multi-layer transparent conductive coating including at least one conductive layer comprising silver, a dielectric layer comprising zinc oxide under and directly contacting the conductive layer comprising silver, and a dielectric layer(s) comprising tin oxide or silicon nitride over the conductive layer comprising silver
Data Source
AI summary
Certain example embodiments relate to capacitive touch panels. First and second glass substrates are substantially parallel and spaced apart from one another. At least one multi-layer transparent conductive coating (TCC) is patterned into electrodes and located between the first and second substrates. The TCC(s) include(s) at least one conductive layer including silver, a dielectric layer including zinc oxide under and directly contacting the conductive layer including silver, and a dielectric layer(s) including tin oxide or silicon nitride over the conductive layer including silver. Processing circuitry electrically connects to the electrodes and measures an aspect of the electrodes' capacitance. A laminate material is located between the first and second glass substrates. The TCC(s), when blanket deposited, may have a visible transmission of at least 88%, a sheet resistances of no more than 10 ohms per square, and a haze of no more than 0.5%. Mutual and self-capacitance designs are disclosed.