Conductive Laser-Engravable Varnish for Touch Control Elements

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Solution Overview

Problem

Existing touch control technologies require separate foils or PCBs for each application, which are time-consuming and costly to produce, and conventional paints cannot create electrically conductive and laserable surfaces for touch control elements.

Innovation Solution

An electrically conductive and laserable paint comprising 3-8% cellulose ester solution, 2-10% guide pigment, 5-20% polyester resin, 5-20% acrylate resin, 0.5-10% powdered magnesium silicate hydrate, and at least one wetting agent, allowing for direct application to substrates and creation of conductive tracks via laser processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional conductive paint is used, then electrical conductivity is achieved, but laserability is lost

Engineering Contradiction:
Improveelectrical conductivityVSAvoidlaserability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a composite paint formulation containing conductive pigments (silver, copper, or aluminum particles), polyester resin, and specific solvents. This composite structure allows the paint to simultaneously achieve electrical conductivity through the metal particles and laserability through the organic binder system that vaporizes cleanly under laser exposure, resolving the contradiction between conductivity and laserability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific parameters including particle size distribution of conductive pigments (0.5-10 μm average diameter), solvent composition (mixtures of esters, ketones, and alcohols), and resin content to balance conductivity and laserability. By adjusting these parameters, the paint achieves both electrical conductivity and clean laser removal without residue formation.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If separate foils or PCBs are used for touch control elements, then functional touch control is achieved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvetouch control functionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a single integrated layer: the conductive paint simultaneously provides electrical conductivity for touch sensing, laserability for symbol generation, and surface coating functionality. This eliminates the need for separate foils, PCBs, and symbol layers, reducing manufacturing complexity while maintaining touch control functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The conductive paint formulation serves multiple purposes: it creates the capacitive sensor layer for touch detection, provides the substrate for laser-generated symbols, and forms a durable protective coating. This multi-functional approach replaces multiple specialized components with a single versatile material system.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If conventional laser paint is used, then laserability is achieved, but electrical conductivity is lost

Engineering Contradiction:
ImprovelaserabilityVSAvoidelectrical conductivity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent incorporates high concentrations of conductive metal particles (silver, copper, or aluminum) within the laserable paint matrix. These particles form interconnected conductive pathways while the organic binder system maintains laserability. The composite structure enables both laser removal for symbol creation and electrical conductivity for touch sensing.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The paint formulation allows different regions to serve different functions: the metal particles provide localized conductivity at contact points, while the organic binder provides localized laserability for symbol generation. This spatial distribution of properties within the single coating layer resolves the contradiction between conductivity and laserability.

Inventive Principle:
Principle #3Local quality

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 the production of touch control elements without separate foils or PCBs, allowing for cost-effective and efficient manufacturing of components with integrated conductive tracks, enhancing aesthetic appeal and operational convenience.

Implementation Method 1

it allows residue-free removal with high contour sharpness when the top layer is removed

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

conductive pigment, in particular silver, copper or aluminum, in each case in the form of particles

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3858924B1Electrically conductive laser-engravable varnish, method for its production and use of the varnish for producing a touch control element
Publication Date: 2022.08.31 NORDWEST CHEM GMBH

AI summary

The invention relates to an electrically conductive, laserable lacquer comprising: - 3-8 wt.% cellulose ester solution, wherein the cellulose ester content in the solution is 2-10 wt.%; - 2-10 wt.% of a conductive pigment; - 5-20 wt.% polyester resin; - 5-20 wt.% acrylate resin; - 0.5-10 wt.% powdered magnesium silicate hydrate; - at least one wetting agent; - and at least one solvent.