Micromechanical Part Coating via Photolithography Etching

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Solution Overview

Problem

Current manufacturing processes for timepieces using micro-machinable materials like crystalline silicon face challenges due to insufficient tribological characteristics and complexity, requiring direct handling that can damage parts.

Innovation Solution

A method involving photolithography to etch a pattern on a micro-machinable material substrate, mounting it on a support for coating, and releasing the part to apply a tribologically superior coating, allowing for pre-assembly without handling the functional parts, using alignment means and a counter-support for secure mounting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If micro-machinable materials like crystalline silicon are used for manufacturing timepiece parts, then manufacturing precision is improved, but tribological characteristics are insufficient

Engineering Contradiction:
Improvemanufacturing precisionVSAvoidtribological characteristics
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent combines micro-machinable material (crystalline silicon) with coating materials (diamond-like carbon, amorphous carbon, or crystalline diamond) to create a composite structure. The substrate provides precise dimensional control while the coating layer provides superior tribological properties, resolving the contradiction between manufacturing precision and reliability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different materials to different parts of the component: the bulk material (crystalline silicon) maintains dimensional precision, while the surface coating (diamond-like carbon or other coatings) provides enhanced tribological characteristics. This local differentiation allows each region to optimize its function.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If direct handling of manufactured parts is performed, then assembly can be completed, but damage risk increases

Engineering Contradiction:
Improveassembly capabilityVSAvoiddamage risk
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent introduces intermediate handling elements (tweezers, forceps, or specialized fixtures) that allow assembly operations without direct finger contact. These intermediaries transfer the part from the manufacturing substrate to the final assembly, eliminating skin oils and mechanical damage risks while maintaining assembly capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent performs preliminary assembly operations (coating application, intermediate fixture attachment) before final handling. By preparing the part with protective coatings and attachment features while still on the manufacturing substrate, the part is made ready for final assembly without requiring subsequent direct handling.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If complex manufacturing processes are used, then part quality can be maintained, but process complexity increases

Engineering Contradiction:
Improvepart qualityVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into integrated manufacturing steps: photolithographic patterning creates both the component geometry and the coating mask pattern simultaneously; the coating process both deposits the tribological layer and defines its precise location; release from the substrate integrates with the final part extraction. This merging reduces the number of separate operations while maintaining quality.

Inventive Principle:
Principle #5Merging (Combining)

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 reliable and precise manufacturing of micromechanical parts with improved tribological properties, ready for assembly into timepieces without direct manipulation of the micro-machinable material, enhancing precision and reducing damage risks.

Implementation Method 1

etching by photolithography, in the entire thickness of said substrate, a pattern comprising said part

Methodology Applied
Scientific EffectPhotolithography: Photography

Implementation Method 2

depositing a coating on the outer surface of said part of better tribological quality than said micro-machinable material

Methodology Applied
Scientific EffectCoating deposition: Deposition (physical)

Data Source

PatentEP2145856B1Method of manufacturing a micromechanical part
Publication Date: 2014.03.12 THE SWATCH GRP RES & DEVELONMENT LTD
  • EP2145856B1 patent drawingFigure 1
  • EP2145856B1 patent drawingFigure 2
  • EP2145856B1 patent drawingFigure 3

AI summary

The invention relates to a method for manufacturing (1) a mechanical part (51) comprising the following steps: a) preparing (3) a substrate (53) made of a micromachinable material; b) etching (5) by photolithography, through the entire thickness of said substrate, a pattern (50) comprising said part; According to the invention, the method (1) further comprises the following steps: c) mounting (7) said etched substrate onto a support (55') so as to leave the upper and lower faces of the latter accessible; d) depositing (9, C') a coating on the outer surface of said part of higher tribological quality than said micromachinable material; e) releasing (11) the part from the substrate. The invention relates to the field of watchmaking component manufacturing.