External part for a timepiece or a piece of jewellery comprising an interferential colour coating and manufacturing method of said part
AssigneeOmega SA
InventorsCorina Barbos, Frédéric Jeanrenaud, Gregory Kissling
Life of this patent
Estimating the term…
Abstract
An external part including a substrate and a coating composed of the following successively superimposed layers; an opaque or semi-opaque reflective layer, configured to have a reflectance of at least 90% for wavelengths including between 600 nm and 780 nm, a transparent or semi-transparent layer, having a refractive index to include between 1.45 and 2.8 for a wavelength of 630 nm, an absorbent layer, the layers giving the coating a predetermined interference colour.
Claims20
An external part comprising a substrate including a coating composed of the following successively superimposed layers:
- an opaque or semi-opaque reflective layer, configured to have a reflectance of at least 90% for wavelengths comprised between 600 nm and 780 nm,
- a transparent or semi-transparent layer, having a refractive index comprised between 1.45 and 2.8 for a wavelength of 630 nm, and
- an absorbent layer,
- said layers giving the coating a predetermined interference colour, said coating having a red colour wherein in the CIELAB chromatic space, illuminating D65, by a parameter L* comprised between 25 and 35, a parameter a* comprised between 8 and 15, and a parameter b* comprised between 0 and 7.
A method for manufacturing an external part for a timepiece or a piece of jewelry, said method comprising the following successive steps of generating a coating on a surface of a substrate:
- depositing an opaque reflective layer on a substrate, said layer being configured to have a reflectance greater than 90% for wavelengths comprised between 600 nm and 780 nm,
- depositing a transparent layer having a refractive index comprised between 1.45 and 2.8 for a wavelength of 630 nm, and
- depositing an absorbent layer,
- wherein the layers give the coating a predetermined interference colour, said coating having a red colour wherein in the CIELAB chromatic space, illuminating D65, by a parameter L* comprised between 25 and 35, a parameter a comprised between 8 and 15, and a parameter b* comprised between 0 and 7.
Dependencies are inferred from the claim text.