US 12,222,531 B2
External part for a timepiece or a piece of jewellery comprising an interferential colour coating and manufacturing method of said part
Corina Barbos, La Chaux-de-Fonds (CH); Frédéric Jeanrenaud, La Chaux-de-Fonds (CH); and Gregory Kissling, La Neuveville (CH)
Assigned to Omega SA, Bienne (CH)
Filed by Omega SA, Bienne (CH)
Filed on Jan. 12, 2022, as Appl. No. 17/573,714.
Claims priority of application No. 21163489 (EP), filed on Mar. 18, 2021.
Prior Publication US 2022/0299689 A1, Sep. 22, 2022
Int. Cl. G02B 5/28 (2006.01); A44C 27/00 (2006.01); C23C 14/08 (2006.01); C23C 14/10 (2006.01); C23C 14/14 (2006.01); C23C 28/00 (2006.01); G04B 19/12 (2006.01); G04B 37/22 (2006.01); G04B 45/00 (2006.01)
CPC G02B 5/285 (2013.01) [A44C 27/006 (2013.01); A44C 27/007 (2013.01); C23C 14/08 (2013.01); C23C 14/10 (2013.01); C23C 14/14 (2013.01); C23C 28/32 (2013.01); C23C 28/3455 (2013.01); G04B 19/12 (2013.01); G04B 37/22 (2013.01); G04B 45/0015 (2013.01)] 20 Claims
OG exemplary drawing
 
1. 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.