Method of fabrication of a black watch dial, and said black watch dial

Abstract

A method of fabrication of a black watch dial, comprising the following steps: providing a substrate (1); deposition of a black coating (2) on said substrate,
wherein said coating (2) comprises carbon nanotubes (21).

Claims

1. A method of fabrication of a black watch dial, comprising the following steps: providing a substrate; deposition of a black coating having carbon nanotubes on the substrate, the black coating having a thickness between 0.05 and 1 mm, the coating having a varnish to prevent the carbon nanotubes from becoming unglued, applying a transparent lacquer on top of the carbon nanotubes to encapsulate the carbon nanotubes, placement of an index on the coating.

2. The method as claimed in claim 1, the substrate being metallic.

3. The method as claimed in claim 2, wherein the varnish comprises at least 0.1 percent by weight of carbon nanotubes.

4. The method as claimed in claim 1, the coating comprising the varnish and carbon nanotubes diluted in the varnish.

5. The method as claimed in claim 4, an axis of the carbon nanotubes being substantially perpendicular to an upper surface of the substrate.

6. The method as claimed in claim 5, the deposition of a coating comprising gluing of a plate with carbon nanotubes on the substrate.

7. The method as claimed in claim 6, the axis of the carbon nanotubes being substantially perpendicular to the upper surface of the plate.

8. The method as claimed in claim 1, the deposition of a coating comprising the growth of carbon nanotubes directly on the substrate.

9. The method as claimed in claim 8, the plate being coated with a mat of carbon nanotubes.

10. The watch dial obtained by the method of claim 1.

11. A black watch dial, comprising a substrate and a layer of black color comprising carbon nanotubes and having a thickness between 0.05 and 1 mm, a varnish preventing the nanotubes from becoming unglued, and further comprising a transparent lacquer on top of the carbon nanotubes in order to encapsulate them, and comprising indexes attached to the layer of black color.

12. The watch dial as claimed in claim 11, comprising a metallic substrate.

13. The watch dial as claimed in claim 11, comprising a metallized substrate.

14. The watch dial as claimed in claim 11, further comprising a coating comprising the varnish and the carbon nanotubes diluted in the varnish.

15. The watch dial as claimed in claim 14, wherein said varnish comprises at least 0.1 percent by weight of carbon nanotubes.

16. The watch dial as claimed in claim 11, the deposition of a coating comprising carbon nanotubes directly on the substrate.

17. The watch dial as claimed in claim 11, an axis of said carbon nanotubes being substantially perpendicular to the upper surface of said substrate.

18. The watch dial as claimed in claim 11, comprising a plate provided with carbon nanotubes on said substrate.

19. The watch dial as claimed in claim 18, said plate being coated with a mat of carbon nanotubes.

20. The watch dial as claimed in claim 19, the axis of said carbon nanotubes being substantially perpendicular to an upper surface of the plate.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Sample embodiments of the invention are indicated in the description illustrated by the enclosed figures in which:

(2) FIG. 1 illustrates a schematic sectional view of a black watch dial according to a first embodiment of the invention.

(3) FIG. 2 illustrates a schematic sectional view of a black watch dial according to a second embodiment of the invention.

(4) FIG. 3 illustrates a schematic exploded sectional view of a black watch dial according to a third embodiment of the invention.

SAMPLE EMBODIMENT(S) OF THE INVENTION

(5) A first embodiment of the invention shall be described with regard to FIG. 1. In this example, the dial comprises a substrate 1, for example, a metallic substrate 1, such as a substrate of brass. The substrate could also be of a nonmetallic material, such as sapphire, whether or not covered by a metallization to facilitate the adhesion of the carbon.

(6) The substrate is covered by a layer of varnish 2 whose very dark black color is obtained by diluting carbon nanotubes 21, such as agglomerated carbon nanotubes, in a base of varnish 20. The size of the nanotubes is highly exaggerated in the figure; in practice, the nanotubes typically have a diameter of several nanometers and a length less than one millimeter.

(7) The carbon nanotubes 21 improve the coefficient of absorption of light of the varnish base and thus make it possible to obtain a very dark varnish. The varnish, for its part, makes it possible to hold the carbon nanotubes and prevent them from becoming unglued and polluting the inside of the watch.

(8) The dial can be pierced by one or more holes 10 for the passage of the watch hand axles. Indexes 11, such as metallic indexes, can be attached on top of the coating 2.

(9) Another embodiment shall be described with regard to FIG. 2. In this example, a sheet (mat) of carbon nanotubes 2 is produced directly on the substrate 1, for example, by evaporation of carbon at high temperature and under high pressure, in a rare gas atmosphere. Other methods of synthesis, including laser ablation or CVD deposition methods, can be employed.

(10) It is possible to have the carbon nanotubes grow on a layer of binder, not shown, on the substrate 2, in order to reduce the risk of ungluing. In the variant illustrated, an optional transparent lacquer 3 is deposited on top of the mat of carbon nanotubes in order to encapsulate them or for aesthetic reasons.

(11) A third embodiment shall be described with regard to FIG. 3. In this example, a sheet (mat) of carbon nanotubes 2 is produced on a rigid or fixed plate 4 which is then fixed to the substrate 1, for example, by gluing with an adhesive 5. As in the variant above, the mat of carbon nanotubes can be produced by evaporation of carbon at high temperature and under high pressure, in a rare gas atmosphere. Other methods of synthesis, including laser ablation or CVD deposition methods, can be employed. This method has the advantage of not exposing the substrate 1 to the high temperature or pressure of the room for creation of carbon nanotubes. In the variant illustrated, an optional transparent lacquer 3 is deposited on top of the mat of carbon nanotubes 2 in order to encapsulate them.