Conductive Paste Printing for Automotive Heater Grid Uniformity

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Solution Overview

Problem

Conventional printing methods for forming heater grids on plastic substrates in automobiles often result in uneven thickness, bubbles, and breaks in conductive lines, leading to reduced efficiency and performance.

Innovation Solution

A printing method using a conductive mixture comprising a conductive paste, solvent, and adhesion agent, specifically designed for inkjet or screen printing, which ensures uniformity and consistency of conductive lines by controlling the viscosity, particle size, and adhesion properties, allowing for precise formation of busbars, grid lines, and antenna lines on plastic substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional printing methods are used to form conductive lines, then the manufacturing process is simple, but the manufacturing precision deteriorates due to uneven thickness, bubbles, and breaks in the lines

Engineering Contradiction:
Improveuniformity of conductive line thicknessVSAvoidcomplexity of printing process control
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by precisely controlling the viscosity of the conductive paste (10,000-50,000 cP), particle size distribution (0.5-5.0 μm average with specific D10-D90 ranges), and solvent content (5-20 wt%) to achieve uniform line thickness and eliminate defects during the printing process

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by using automated printing machines with computer-controlled positioning systems that can dynamically adjust printing parameters such as print head speed, deposition rate, and substrate feeding speed to maintain consistent line quality throughout the manufacturing process

Inventive Principle:
Principle #15Dynamics

2Reliability

If conventional printing methods are used, then the ease of manufacture is high, but the reliability deteriorates due to breaks and defects in conductive lines

Engineering Contradiction:
Improveintegrity of conductive linesVSAvoidsimplicity of printing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by performing thorough mixing of conductive paste components with specific particle size distributions and viscosity characteristics before printing, and by pre-calibrating the automated printing system to ensure optimal deposition parameters are established before production begins

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback through automated printing machines that use sensors to monitor line formation in real-time and automatically adjust printing parameters to correct deviations, ensuring consistent line integrity and eliminating defects through closed-loop control

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If conventional printing methods are used, then the productivity is moderate, but the manufacturing precision deteriorates resulting in reduced defroster efficiency

Engineering Contradiction:
Improveuniformity of conductive line thicknessVSAvoidproduction speed of defroster
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces manual printing operations with automated printing machines that use computer-controlled mechanisms for substrate feeding, print head positioning, and parameter adjustment, thereby maintaining high manufacturing precision while significantly increasing production speed and consistency

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3374194B1Methods of printing with conductive paste
Publication Date: 2019.08.14 EXATEC LLC
  • EP3374194B1 patent drawingFigure 1~2
  • EP3374194B1 patent drawingFigure 3~4B
  • EP3374194B1 patent drawingFigure 5~6

AI summary

In an embodiment, a printing method for forming a conductive line on a plastic substrate for use in an automobile, comprises one or both of inkjet printing and screen printing the conductive line on the plastic substrate while the plastic substrate is fixed in a fixture of an automatic printing machine; the conductive mixture comprises a conductive paste; a solvent; and an adhesion agent; and wherein the conductive line is a busbar, a grid line, or an antenna line in the automobile.