Dark Black Surface Structure Using Aligned Rod Light Cavities
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Solution Overview
Problem
Existing methods for producing intense black surfaces, such as those used in external horology parts, are inefficient and lack the ability to effectively absorb light, particularly when using carbon nanotubes grown on etched aluminum surfaces.
Innovation Solution
A method involving directional solidification to grow crystalline rods aligned with a matrix phase, followed by selective removal of the matrix to create a comb-like structure with light entrapment cavities, enhancing light absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If carbon nanotubes are grown on etched aluminum surfaces using chemical vapour deposition, then a black surface is produced, but the light absorption capability is insufficient and the process is inefficient
Solution Approach 1:
The material is segmented into two distinct phases during directional solidification: a crystalline phase forming aligned rod structures and a matrix phase filling the spaces between. This segmentation allows selective removal of the matrix to create the comb-like structure with light-trapping cavities, achieving superior light absorption compared to uniform carbon nanotube coatings.
Solution Approach 2:
The invention creates local quality variations by having the crystalline phase form rod structures in specific orientations while the matrix occupies different regions. After selective matrix removal, the resulting structure has localized light-trapping cavities between the rods, providing enhanced light absorption at specific locations rather than uniform coverage.
2Illumination intensity
If a comb-like structure with light entrapment cavities is formed by removing the matrix, then light absorption is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The comb-like structure with light entrapment cavities is created as a preliminary feature during the directional solidification process itself, rather than being added as a subsequent complex manufacturing step. The matrix removal is performed selectively to reveal the pre-formed rod structure, simplifying the overall manufacturing process while achieving enhanced light absorption.
Solution Approach 2:
The invention utilizes phase transitions during directional solidification to naturally form the two-phase structure (crystalline rods and matrix). By controlling the solidification process, the desired comb-like structure is created through material phase separation rather than complex mechanical or chemical processing steps.
3Shape
If directional solidification is used to grow aligned crystalline rods, then a structured material is produced, but the manufacturing process requires precise control of solidification conditions
Solution Approach 1:
The directional solidification process serves multiple functions simultaneously: it forms the aligned rod structure, creates the two-phase material distribution, and establishes the geometric configuration for subsequent matrix removal. This multi-functionality reduces the need for separate precision control steps for each structural feature.
Solution Approach 2:
The invention achieves rod alignment by systematically changing solidification parameters (temperature gradient, cooling rate, solidification direction) during the directional solidification process. By optimizing these parameters, the crystalline phase naturally forms aligned rod structures without requiring extremely precise control, as the phase transition process itself guides the structure formation.
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 method produces a dark black surface with improved light absorption capabilities, suitable for external horology parts, by aligning crystalline rods and removing the matrix to form a comb-like structure with light entrapment cavities.
Implementation Method 1
growing the material in a main direction so that the at least one crystalline phase forms a plurality of rods aligned with each other
Implementation Method 2
removing at least part of the matrix between said rods of the at least one crystalline phase, so as to form a comb-type material structure with rods and light entrapment cavities between said rods, so as to absorb light
Data Source
AI summary
A method for manufacturing a black structure of a material (10) including at least two phases, with at least one crystalline phase (1) and at least one other phase, referred to as the matrix (2). The steps include growing the material in a main direction (Z) so that the at least one crystalline phase forms a plurality of rods aligned with each other and the matrix extends between the rods; and removing at least part of the matrix between the rods of the at least one crystalline phase, so as to form a comb-type material structure with rods and light entrapment cavities between said rods.