US 11,698,567 B2
Coloured PVB
Théo Chevallier, Paris (FR); and Hannah Ray, Minneapolis, MN (US)
Assigned to SAINT-GOBAIN GLASS FRANCE, Courbevoie (FR)
Appl. No. 16/651,120
Filed by SAINT-GOBAIN GLASS FRANCE, Courbevoie (FR)
PCT Filed Sep. 20, 2018, PCT No. PCT/FR2018/052295
§ 371(c)(1), (2) Date Mar. 26, 2020,
PCT Pub. No. WO2019/063911, PCT Pub. Date Apr. 4, 2019.
Claims priority of application No. 1759138 (FR), filed on Sep. 29, 2017.
Prior Publication US 2020/0225550 A1, Jul. 16, 2020
Int. Cl. G02F 1/163 (2006.01); B32B 17/10 (2006.01); G02F 1/157 (2006.01)
CPC G02F 1/163 (2013.01) [B32B 17/10036 (2013.01); B32B 17/10513 (2013.01); B32B 17/10651 (2013.01); B32B 17/10761 (2013.01); G02F 1/157 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A process for modifying the color in transmission of an optical system from an initial state having an initial color (L*i; a*i; b*i) to a final state having a final color (L*f; a*f; b*f), said process comprising at least one step of modifying the absorbance properties of an optical element of said optical system so that at least 50% of the total absorption (A) of said optical element occurs in an effective absorption range ([λmin; λmax]) defined so that a variation in absorption by the optical system of any amount of light at a wavelength λ comprised in said effective absorption range ([λmin; λmax]) generates a variation ΔC(λ) in chromaticity distance (Ci, C(λ)) smaller than 0, where:
ΔC(λ)=C(λ)−Ci=√(a*(λ)−a*ref)2+(b*(λ)−b*ref)2−√(a*i−a*ref)2+(b*i−b*ref)2
(Ci, C(λ)) is the chromaticity distance between a given value ((a*i; b*i), (a*(λ); b*(λ))) of chromaticity in transmission and a reference value (a*ref; b*ref) of chromaticity in transmission,
(a*i; b*i) is the initial value of chromaticity in transmission,
(a*(λ); b*(λ)) is the value of chromaticity in transmission obtained following the variation in absorption achieved at the wavelength λϵ[λmin; λmax].