Antireflective Stack for Low Luminance Conditions
AssigneeEssilor International (Compane Generale D'Optique
InventorsYu LIU, Xingzhao DING
Life of this patent
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Abstract
Ophthalmic lens comprising an anti-reflective stack designed for scotopic or mesopic conditions, wherein the anti-reflective stack design method uses the scotopic luminosity function CIE 1951 (defined by the Commission Internationale de I'Eclairage).
Claims17
An ophthalmic lens comprising an anti-reflective stack designed for scotopic or mesopic conditions, wherein the anti-reflective stack design method uses the spectral luminous efficiency function V′(λ) as defined in CIE 1951.
A method of designing an anti-reflective stack comprising:
- (a) identifying a luminance in the scotopic vision regime;
- (b) calculating the weighted mean light reflection in scotopic conditions R′V of an anti-reflective stack having a light reflection spectrum R(λ) according to:
- R
- V
- ′
- =
- ∫
- 380
- 780
-
- R
-
- (
- λ
- )
- ·
- V
- 0
- ,
- 1
-
- (
- λ
- )
- ·
- Ilum
-
- (
- λ
- )
- ·
- d
-
-
- λ
- ∫
- 380
- 780
-
- V
- 0
- ,
- 1
-
- (
- λ
- )
- ·
- Ilum
-
- (
- λ
- )
- ·
- d
-
-
- λ
- (c) designing an anti-reflective stack by selecting materials to achieve the light reflection spectrum RO(λ) yielding the calculated R′V value,
- wherein V0,1(λ)=V′(λ) is in CIE 1951 and Ilum(λ) is a reference illuminant.
A method of designing an anti-reflective stack comprising:
- (a) identifying a range of luminance in the scotopic and/or mesopic vision regime;
- (b) calculating the average spectral luminous efficiency function Vα,β(λ) of the range of luminance according to:
- Vα,β(λ)=αV(λ)+βV′(λ)
- wherein α and β are selected according to the luminance conditions, β>0, V(λ) is in CIE 1931 and V′(λ) is in CIE 1951;
- (c) designing an anti-reflective stack by use of Vα,β(λ) function.
A method of providing to a customer of an ophthalmic lens a rating of the ophthalmic lens with respect to luminance conditions, the rating being based on a ratio which quantifies the anti-reflective efficiency of the ophthalmic lens in scotopic or mesopic conditions, the method comprising the steps of:
- (a) identifying a range of luminance in the scotopic and/or mesopic vision regime;
- (b) identifying the average spectral luminous efficiency function Vα,β(λ) adapted to this range of luminance and calculating a ratio based on α and β;
- and
- (c) providing to a customer the rating of the ophthalmic lens.
An ophthalmic lens rated for quantifying the anti-reflective efficiency of ophthalmic lens in scotopic and/or mesopic conditions, the ophthalmic lens comprising a front face coated with a multilayered anti-reflective stack and an indication of a visual rating associated with the ophthalmic lens, the rating including a ratio based on values α and β defining the average spectral luminous efficiency function Vα,β(λ) used for designing the anti-reflective stack.
Dependencies are inferred from the claim text.