Micromechanical Component with Conductive Layer Texture

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Solution Overview

Problem

Existing micromechanical components in the watchmaking field, coated with conductive layers for tribological improvement, suffer from wear-induced discontinuity in friction zones, leading to loss of conductivity.

Innovation Solution

A micromechanical component with a textured surface featuring recesses coated with a conductive layer, produced using the DRIE process, maintains continuity of the conductive layer during wear by retaining the layer within the recesses, ensuring electrical conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conductive layer is deposited on a micromechanical component to improve tribology and conductivity, then the surface conductivity and tribological properties are improved, but the conductive layer wears away in friction zones leading to discontinuity and loss of conductivity

Engineering Contradiction:

Improveconductivity continuityVSAvoidconductive layer wear

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The surface is segmented into hollows and ridges, creating a textured topography that traps the conductive layer within the hollows. This segmentation prevents the conductive layer from being completely worn away, as the hollows act as reservoirs that maintain conductivity even when the ridges experience wear.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The hollows are pre-formed on the surface before the conductive layer is deposited. This preliminary action creates predetermined zones where the conductive layer will be retained during wear, ensuring continuous conductivity without requiring additional measures during operation.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If the DRIE process is used to machine the component, then precise surface texturing with hollows is achieved, but a wavy profile is created that typically requires additional oxidation and deoxidation steps to smooth

Engineering Contradiction:

Improvesurface texture precisionVSAvoidmanufacturing process steps

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The wavy profile, which is normally considered a defect requiring additional processing steps, is converted into a beneficial feature. The waves created by the DRIE process are retained and utilized as the hollows that will trap the conductive layer, eliminating the need for oxidation and deoxidation steps while achieving the desired functionality.

Inventive Principle:

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

Solution Approach 2:

Instead of trying to eliminate the wavy profile as is conventionally done, the invention inverts the approach by deliberately maintaining and utilizing the waves. The wavy profile is transformed from a harmful defect into a useful feature that enables the conductive layer retention mechanism.

Inventive Principle:

Principle #13The other way round (Inversion)

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 solution effectively maintains a continuous conductive layer despite wear, ensuring electrical conductivity and preventing electrostatic charge accumulation in friction zones.

Implementation Method 1

The manufacturing process used is the deep reactive ion etching (DRIE) process

Methodology Applied

Scientific EffectDeep Reactive Ion Etching: Plasma

Implementation Method 2

the simplest solution is to deposit a metallic layer, typically by PVD

Methodology Applied

Scientific EffectPhysical Vapor Deposition: Physical Vapour Deposition

Data Source

PatentEP3742237B1Component, in particular for a timepiece, with a surface topology and manufacturing method thereof

Publication Date: 2024.10.16 NIVAROX FAR SA

Figure 1A~2A
Figure 2B~3(d)

AI summary

The invention relates to a component (1) intended to be in contact by friction with another component, said component (1) being coated with an electrically conductive layer (4) in one piece covering at least partially each of the surfaces of the component (1), the friction being established on at least one of these surfaces, called the functional surface (2), said functional surface (2) being framed by a plurality of lateral surfaces (3), the component (1) having on its functional surface (2) a texture formed of a succession of grooves (2a) coated with said electrically conductive layer (4), said grooves (2a) each extending between two lateral surfaces (3) so as to keep the layer (4) in one piece over the whole of the component (1) despite the wear caused by the friction on the functional surface (2).It also relates to the manufacturing process by deep reactive ion etching (DRIE) of the component (1), the surface defects on the flank machined by the DRIE process being exploited to carry out said excavations (2a).