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US 12,724,187 B2Granted
Optical filter
AssigneeChangkang Chemical Co., Ltd.
InventorYoung Tae Heo
Life of this patent
Estimating the term…
Abstract
In the present application, a sharp visible light transmission band can be obtained while efficiently and accurately blocking ultraviolet light near the short-wavelength visible light region and infrared light near the long-wavelength visible light region, and the ripple phenomenon can be minimized regardless of the incident angle. It is possible to provide an optical filter capable of obtaining high visible light transmittance while securing the above characteristics even in the case where a near-infrared absorption glass is used as a substrate.
Claims12
An optical filter comprising:
- a transparent substrate being a near-infrared absorption glass substrate;
- and
- a dielectric film formed on one or both surfaces of the transparent substrate and comprising two or more sub-layers including a first sub-layer and a second sub-layer having different refractive indices and alternately stacked, wherein a ripple value at an incident angle of 0° is 2.5% or less in a wavelength range of 450 nm to 560 nm,
- wherein the first sub-layer and the second sub-layer are formed such that a V value according to the following Equation 2 is 17 or less:
- V=K×{[(n1/n2)2p×(n12/ns)−1]/[(n1/n2)2p×(n12/ns)+1]}2, [Equation 2]
- wherein n1 is a refractive index of the first sub-layer, n2 is a refractive index of the second sub-layer, ns is a refractive index of the transparent substrate, K is a total number of the first sub-layer and the second sub-layer in the dielectric film being 15 or less, p is a number satisfying K=(2p+1), and a ratio of the total number of the first sub-layers and the second sub-layers to the total number of the two or more sublayers is 80% or more.
3 more elements
Dependencies are inferred from the claim text.