Capacitive Touch Panel with Acid-Etched Diffuser Glass
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Solution Overview
Problem
Current transparent projection screens lack interactive capabilities, limiting their application in augmented reality and other touch-based systems.
Innovation Solution
A capacitive touch panel integrated into a projection screen, featuring acid-etched glass substrates with a conductive coating patterned into electrodes, allowing for interactive functionality and improved conductivity compared to traditional ITO coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ITO coatings are used for conductive layers, then transparency is maintained, but conductivity is insufficient for interactive touch panel applications
Solution Approach 1:
The patent employs multi-layer composite conductive coatings combining different materials (e.g., ITO with aluminum, or ITO with nickel-chromium-silver-nickel-chromium stacks) to achieve both high conductivity and transparency. The composite structure leverages the complementary properties of each material layer to overcome the limitations of single-material coatings.
Solution Approach 2:
The patent optimizes coating parameters including thickness control (controlling ITO layer thickness to balance transparency and conductivity), sheet resistance values (targeting specific Rs ranges for touch panel performance), and deposition conditions to achieve the desired electrical and optical properties simultaneously.
2Illumination intensity
If glass substrates are acid-etched to form diffusers, then light scattering and transparency are improved, but surface smoothness and coating adhesion may be compromised
Solution Approach 1:
The acid etching process creates localized surface variations with controlled roughness (typically Ra 0.1-10 micrometers) that provide light scattering centers while maintaining overall substrate integrity. The etching parameters (acid concentration, etching time, temperature) are precisely controlled to achieve the desired local surface quality without compromising global surface uniformity.
Solution Approach 2:
The glass substrate undergoes preliminary acid etching and surface preparation before conductive coating deposition. This preliminary treatment creates an optimized surface morphology that enhances subsequent coating adhesion and ensures uniform coating formation, preventing defects that would arise from applying coatings directly to unetched surfaces.
3Reliability
If multiple coating layers are deposited to improve conductivity, then electrical performance is enhanced, but manufacturing complexity and cost increase
Solution Approach 1:
The conductive coating is segmented into multiple functional layers, each with specific roles: a transparent conductive oxide layer (ITO) for baseline conductivity and transparency, intermediate metal layers (aluminum, nickel-chromium) for enhanced conductivity and barrier properties, and protective outer layers for durability. This segmentation allows optimization of each layer's thickness and composition for its specific function.
Solution Approach 2:
The multi-layer coating structure serves multiple functions simultaneously: electrical conduction, optical transparency, mechanical protection, adhesion enhancement, and corrosion resistance. Each layer contributes to one or more of these functions, making the complex structure universally beneficial for touch panel applications rather than merely additive 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
Enables interactive transparent displays for augmented reality and various applications while maintaining transparency and conductivity, enhancing user interaction and system performance.
Implementation Method 1
a major first surface of the first glass substrate is acid etched to form a diffuse surface
Implementation Method 2
a first patterned coating formed on the diffuse surface of the first glass substrate, wherein the first patterned coating comprises a conductive layer
Implementation Method 3
a capacitive touch panel integrated into a projection screen, featuring acid-etched glass substrates with a conductive coating patterned into electrodes
Data Source
AI summary
A projection screen including a capacitive touch panel, such as a projected capacitive touch panel. The touch panel includes first and second glass substrates, one of which is patterned (e.g., etched with acid or the like) to form a diffuser. A conductive coating is formed on the patterned surface of the diffuser glass substrate, and is patterned into a plurality of electrodes for the touch panel. The system, including an optional projector, may be used as an interactive transparent display for augmented reality applications such as storefronts. The touch panel may also be used in applications such as capacitive touch panels for controlling showers, appliances, vending machines, electronics, electronic devices, and/or the like.