Automotive Metallic Decoration With PVD Interference Color Gradient

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Solution Overview

Problem

Current techniques for decorating plastic automobile parts with metallic finishes lack the ability to create color gradients and are economically and environmentally costly due to the need for pigments, which also pose toxicity concerns.

Innovation Solution

A method involving physical vapor deposition to apply a reflective metal layer and a transparent interference layer with varying thickness, creating an interference gradient that produces a colored appearance without the use of pigments, using a configuration that allows for precise control of the gradient portion without complex modifications to existing production tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a translucent colored varnish with pigments is applied to metallized parts, then a colored metallic appearance is obtained, but the technique cannot produce color gradients and requires high economic and ecological cost due to pigment preparation and use

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcolor variation capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent applies optical interference effects through a transparent coating layer with varying thickness to produce color gradients on metallized parts. Instead of using pigmented varnishes, the invention utilizes the physical phenomenon of light interference where the thickness of the transparent layer (ranging from 0 to several micrometers) determines the perceived color, enabling continuous color transitions and gradients across the part surface.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The invention changes the physical parameter of the transparent coating layer thickness to achieve color variation. By controlling the thickness distribution of the transparent layer during the metallization process, the patent creates different interference patterns that result in different colors, thereby achieving color gradients without requiring multiple pigmented coatings.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If pigments are incorporated into varnish for coloring metallized parts, then colored appearance is achieved, but environmental impact and toxicity concerns increase

Engineering Contradiction:
Improvecolor consistencyVSAvoidenvironmental impact
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the chemical mechanism of pigment-based coloring with a physical mechanism of optical interference. Instead of relying on chemical pigments that have environmental and toxicity concerns, the invention uses the physical interaction of light with layers of different thicknesses to produce color effects, thereby eliminating the need for harmful chemical substances while maintaining color consistency.

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

Solution Approach 2:

The invention converts the typically unwanted effect of light reflection and interference into a beneficial coloring mechanism. By carefully controlling the thickness of the transparent layer, the patent transforms optical interference (which can cause unwanted iridescence) into a controlled coloring system that produces consistent and desirable color effects without using harmful pigments.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If uniform varnish coating is applied to achieve colored appearance, then simple manufacturing process is maintained, but color gradients and variations cannot be created

Engineering Contradiction:
Improvecolor gradient capabilityVSAvoidcoating process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the transparent coating layer during the metallization process itself, before the part is removed from the coating chamber. By controlling the deposition parameters and chamber configuration during this preliminary stage, the invention creates the desired thickness variations and color gradients in a single operation, avoiding the need for subsequent complex multi-step coating processes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent makes the metallization coating chamber perform multiple functions: it not only deposits the metallic reflective layer but also applies the transparent coloring layer with controlled thickness variations. This multi-functionality eliminates the need for separate coating equipment and processes, achieving color gradient capability without significantly increasing overall device complexity.

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

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

This method enables the creation of aesthetically pleasing, economically viable, and environmentally friendly metallic decorations with color gradients on automobile parts, reducing the need for pigments and minimizing environmental impact.

Implementation Method 1

forming an interference gradient on the automotive part, comprising the physical vapor deposition, in a physical vapor deposition chamber, of a transparent layer called interference on all or part of the at least one reflective metal layer

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 2

a so-called gradient portion of variable thickness of the transparent interference layer is formed at the boundary between said visible part and said non-visible part

Methodology Applied
Scientific EffectOptical interference: Interference

Data Source

PatentEP4491758A1Method for applying a metal decoration to a substrate of a motor part, motor part comprising a metal decoration and motor vehicle comprising such a part
Publication Date: 2025.01.15 THE PLASTIVALOIRE GROUP
  • EP4491758A1 patent drawingFigure 1
  • EP4491758A1 patent drawingFigure 2
  • EP4491758A1 patent drawingFigure 3

AI summary

The invention relates to a method (300) for applying a metallic decoration to a substrate (110) of an automotive part (100), comprising the steps of: - providing a substrate (110) made of plastic material; - metallizing the substrate (110) by depositing a reflective metallic layer (120) on the substrate (110); - to form an interference gradient on the automotive part (100), comprising the PVD deposit, in a deposition chamber (200), of a transparent layer (130) interfering on the metallic layer (120), said chamber (200) being configured so that a visible part of the automotive part (100) is in the direct line of sight of a target (210) of base material, and a so-called non-visible part is not permanently in the direct line of sight, so that a portion of gradient (P) of variable thickness of the transparent layer (130) is formed at the boundary between the visible and non-visible parts.