Conductive Paste for Gravure Offset Printing
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Solution Overview
Problem
Existing conductive pastes fail to produce high-linearity, fine conductive patterns with bezel-pattern recesses in gravure offset printing due to inadequate composition, leading to disconnections and short circuits.
Innovation Solution
A conductive paste with a lower content of non-volatile organic compounds relative to conductive metal particles and organic solvents, specifically a mass ratio of 1.0% to 3.0% and a ratio of 0.07 to 0.15 for organic compounds to metal particles, using conductive metal particles, organic compounds solid and liquid at 50°C with boiling points above 300°C, and an organic solvent with a boiling point between 170°C to 300°C, ensuring suitable viscosity and adhesion for complex recesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive paste with higher content of non-volatile organic compounds is used, then adhesion and film hardness are improved, but printing suitability for complex bezel-pattern recesses deteriorates, causing disconnections and short circuits
Solution Approach 1:
The patent changes the chemical composition parameters of the conductive paste by specifying exact ratios of non-volatile organic compounds (1.0-3.0% relative to total paste) and organic solvents (65-75% relative to total paste), replacing conventional formulations. This parameter optimization enables the paste to flow into complex bezel-pattern recesses without disconnection while maintaining adequate adhesion and conductivity after drying.
Solution Approach 2:
The patent creates a composite conductive paste formulation combining conductive metal particles with specific non-volatile organic compounds (polyester resin, acrylic resin) and organic solvents (glycol ethers, esters) in optimized ratios. This composite formulation provides both printing suitability for complex patterns and reliable conductive properties, resolving the contradiction between manufacturability and reliability.
2Manufacturing precision
If screen printing is used to form fine conductive patterns, then pattern precision is improved, but productivity and cost-effectiveness deteriorate
Solution Approach 1:
The patent replaces the mechanical screen printing process with gravure offset printing, substituting a high-precision but low-productivity mechanical method with a high-speed rotary printing system. The optimized conductive paste formulation enables this substitution by providing sufficient flowability to fill fine gravure cells (50 μm or less line width) while maintaining pattern definition, thus achieving both precision and productivity.
Solution Approach 2:
The patent modifies the rheological parameters of the conductive paste by adjusting organic solvent content (65-75%) and viscosity modifiers, enabling the paste to be printed at high speeds using gravure offset printing. This parameter optimization allows line widths of 50 μm or less to be achieved with gravure printing, matching screen printing precision while enabling mass production.
3Reliability
If high temperature and long duration firing is used, then conductivity and adhesion are improved, but substrate damage and production time increase
Solution Approach 1:
The patent changes the thermal processing parameters by optimizing the organic compound composition (polyester resin, acrylic resin with specific boiling points) to enable low-temperature firing (80-150°C) for short durations (1-30 minutes). This parameter modification allows adequate adhesion and conductivity to be achieved without subjecting plastic film substrates to high temperatures that would cause damage, while significantly reducing production time.
Solution Approach 2:
The patent utilizes the phase transition properties of organic solvents (boiling point 170-300°C) and organic compounds (boiling point >300°C) during firing. The controlled evaporation and curing processes occur at low temperatures due to the specific selection of organic materials, enabling rapid drying and curing that achieves reliable conductive film properties without high-temperature damage to plastic substrates.
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 conductive paste enables the formation of high-linearity, fine conductive patterns with no disconnections or short circuits, even with complex bezel-pattern recesses, facilitating high productivity and conductivity in gravure offset printing.
Implementation Method 1
printing films are dried or cured to thereby easily acquire conductivity
Implementation Method 2
firing is performed to form a conductive pattern
Data Source
AI summary
A conductive paste providing an intended conductive pattern having high linearity and having no disconnection, short circuits, or the like even in the case of performing gravure offset printing with a gravure plate having a bezel pattern. A conductive paste for bezel-pattern printing performed by a gravure offset printing process includes conductive metal particles (A); an organic compound (B) that is solid at 50° C. and has a boiling point of more than 300° C. at normal pressure; an organic compound (C) that is liquid at 50° C. and has a boiling point of more than 300° C. at normal pressure; and an organic solvent (D) that is not the (B) or (C), does not have reactivity with the (B) or (C), and has a boiling point of 170° C. to 300° C. at normal pressure. A method for forming a conductive pattern by a gravure offset printing process employs the above-described conductive paste.