Method for manufacturing luminescent hands

Patent metadata

Field	Value
Publication number	US-12468260-B2
Application number	US-202118037612-A
Country	US
Kind code	B2
Filing date	Sep 2, 2021
Priority date	Dec 11, 2020
Publication date	Nov 11, 2025
Grant date	Nov 11, 2025

Abstract

A method for manufacturing a luminescent hand for a horological movement, preferably for a watch. The method includes providing a support comprising a light guide and structuring an emergent surface of the light guide so as to extract a maximum amount of light from the luminescent hand. The luminescent hand includes, over a lower face, a layer of luminescent material including one or more deposit(s) of fluorescent material, opposite a light source. The light source is laced at locations close to the axis of rotation or away from the axis of rotation but at a distance from the luminescent material. Thus, the light source is not placed on the luminescent hand.

First claim

The invention claimed is:

1 . A method for manufacturing at least one luminescent hand for a horological movement, the manufacturing method comprising:
providing at least one support supporting the luminescent hand; and forming on the at least one support a light guide comprising at least one emergent surface and being configured to guide a light, the forming step including the following sub-steps:
depositing on said support at least one layer of a first optical material comprising a first refractive index and allowing preventing the light from being absorbed by the support;
depositing at least one layer of luminescent material over the at least one layer of the first optical material;
depositing of at least one layer of a second optical material, said at least one layer of a second optical material comprising a second refractive index; and,
structuring said at least one emergent surface so that this emergent surface is rough so as to extract the light from said at least one light guide.

2 . The manufacturing method according to claim 1 , wherein said at least one structuring is carried out by abrasion, by ablation, by sandblasting, by stamping and/or photo-structuring.

3 . The manufacturing method according to claim 1 , wherein said deposition of said at least one layer of a first optical material comprises a heat treatment step.

4 . The manufacturing method according to claim 1 , wherein said at least one deposition of at least one layer of luminescent material comprises fluorescent pigments.

5 . The manufacturing method according to claim 1 , wherein said first refractive index is lower than said second refractive index.

6 . A luminescent hand for a horological movement comprising:
a support supporting the hand; and a light guide, said at least one light guide comprising at least:
a layer of a first optical material comprising a first refractive index and allowing preventing light from being absorbed by the support;
a layer of luminescent material over the at least one layer of the first optical material;
a layer of a second optical material comprising a second refractive index; and
an emergent surface configured to be rough so as to extract light from said at least one light guide.

7 . The luminescent hand according to claim 6 , wherein said first refractive index is lower than said second refractive index.

Assignees

• Swatch Group Res & Dev Ltd

Inventors

• Tortora Pierpasquale
• Blatter Cédric
• Gernez Cyrille

Classifications

• G04B19/32

  by luminescent substances {(disc or drum shaped indicating means with marks or windows G04B19/04; with numbers or number-marks G04B19/20; cases for housing the electrical parts G04G17/00; projection of hands and/or scales on weighing apparatus G01G19/00; on measuring instruments G01D5/262; for advertising G09F19/18)} · CPC title

• G04B45/0007

  Light-, colour-, line-, or spot-effects caused by parts or pictures moved by the clockwork (disc-shaped indicating parts G04B19/046, G04B19/202; figures or parts thereof for indicating the time, moved by the clockwork G04B25/06) · CPC title

• G04B19/042 Primary

  Construction and manufacture of the hands; arrangements for increasing reading accuracy (hands with illumination G04B19/305; specially shaped hands, e.g. figures or pictures G04B45/0061; clockwork in the hands G04B45/043; invisible drive of the hands G04B45/046) · CPC title