Watch Dial Carbon Nanotube Layer Reduces Light Reflection
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Solution Overview
Problem
Existing watch dials with black coloration suffer from excessive light reflection under strong direct illumination, compromising readability due to the use of conventional varnishes and paints, including those with vapor-deposited amorphous carbon, which fail to provide sufficient contrast and legibility.
Innovation Solution
A multilevel watch dial design incorporating a first substrate with a tinted layer containing carbon nanotubes, which enhances contrast and minimizes light reflections, featuring windows formed by selective deposition of the carbon nanotube layer, and a second substrate with a light source, such as a luminescent coating or LED, to improve visibility and readability under strong illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional varnishes and paints are used to color the top plate black, then the dial can be manufactured with standard materials and processes, but the surface reflects too much incident light to provide sufficient readability in strong direct light
Solution Approach 1:
The patent changes the material composition parameter by incorporating carbon nanotubes (0.1-5% by mass) into the varnish or paint formulation. This parameter change transforms the optical properties of the coating, reducing light reflection from conventional levels to below 5% reflectivity, while maintaining manufacturability through standard application processes.
Solution Approach 2:
The patent creates a composite material by combining conventional varnish or paint with carbon nanotubes. This composite achieves superior light absorption properties (reflectivity < 5%) compared to conventional materials, while still being applicable through standard coating equipment and processes, thus resolving the contradiction between ease of manufacture and reduction of light reflection.
2Object-affected harmful factors
If vapor deposited amorphous carbon is used to form the black color, then a dark color is achieved, but the contrast and readability remain insufficient under strong direct light
Solution Approach 1:
The patent changes the material composition from vapor-deposited amorphous carbon to a varnish or paint containing carbon nanotubes (0.1-5% by mass). This parameter change achieves superior light absorption (reflectivity < 5%) and maintains color stability, thereby improving readability and contrast under strong direct light while preventing information loss.
3Object-affected harmful factors
If a deep black color is achieved through multiple coating layers or heavy material application, then light reflection is reduced, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The patent uses a composite material formulation (varnish or paint with 0.1-5% carbon nanotubes by mass) that achieves deep black color and low light reflection ( < 5% reflectivity) in a single coating layer. This eliminates the need for multiple coating layers or heavy material application, thereby reducing manufacturing process complexity and time while maintaining superior optical performance.
4Loss of information
If the carbon nanotube layer is applied densely to maximize light absorption, then readability improves, but the cost of materials and application increases
Solution Approach 1:
The patent optimizes the carbon nanotube concentration parameter to the range of 0.1-5% by mass in the varnish or paint formulation. This parameter range achieves the optimal balance between light absorption (reflectivity < 5%) and cost-effectiveness, providing sufficient readability improvement without excessive material cost or application complexity.
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 use of carbon nanotubes in the dial's layer achieves a deep black color with high light absorption, ensuring adequate contrast and reduced light reflections, even under strong direct light, thereby enhancing readability and legibility.
Implementation Method 1
The use of carbon nanotubes in the layer gives the first substrate a particularly deep blackness, which improves the contrast with the surface of said zone of the second substrate visible through the openings. This contrast is even sufficient to confer an adequate contrast when the dial is subjected to strong direct illumination, and minimizes the reflections of light from its surface.
Implementation Method 2
minimizes the reflections of light from its surface
Data Source
Figure 1
Figure 2~3a
Figure 4
AI summary
A dial (1) for a timepiece, comprising: - a first substrate (3) comprising a first surface (19) intended to be located opposite a watch crystal and a second surface (20) opposite said first surface (19), said first substrate (3) further comprising at least one window (5) serving as an index; - at least one second substrate (7) fixed to said first substrate (3) opposite said second surface (20) and associated with a light source (11; 11, 11a), said second substrate (7) comprising an area opposite said at least one window (5); - a tinted layer (21) located on at least a portion of said first surface (19) of said first substrate (3). According to the invention, said layer (21) comprises carbon nanotubes.