OPTICAL FILTER

• Main Authors: TAKAHOSHI HIDEAKI, KAWAI KEISUKE, FUJIWARA AKIO, TAKEMOTO KAZUYA
• Format: Patent
• Language: English; Japanese
• Published: 28.08.2023
• Subjects: OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS

To provide an optical filter that excels in the capability of shielding visible light of 400 to 680 nm and in the permeability of near-infrared light of 800 nm and onward, and which has peeling resistance and exhibits a black color.SOLUTION: Provided is an optical filter comprising a substrate and a dielectric multilayer film which is a laminate composed of a low refractive index film and a high refractive index film, wherein one of the low refractive index film and the high refractive index film has an extinction coefficient k600 of 0.12 or greater in a wavelength 600 nm and a minimum extinction coefficient k800-1570MIN of 0.01 or smaller in the wavelength region of 800 to 1570 nm, or has a spin density of 5.0×1010 (pcs./nm*cm2) or greater. The optical filter satisfies all of specific spectral characteristics (ii-1) to (ii-3), and the high refractive index film is a silicone film whose minimum value of oxygen concentration is 7 to 30 atm%.SELECTED DRAWING: Figure 1 【課題】４００～６８０ｎｍの可視光の遮蔽性と、８００ｎｍ以降の近赤外光の透過性に優れ、耐剥離性を有し、黒色を呈する光学フィルタを提供すること。【解決手段】基材と、低屈折率膜と高屈折率膜とが積層された積層体である誘電体多層膜とを備える光学フィルタであって、前記低屈折率膜および前記高屈折率膜のいずれか一方は、波長６００ｎｍにおける消衰係数ｋ６００が０．１２以上かつ８００～１５７０ｎｍの波長領域における最小消衰係数ｋ８００－１５７０ＭＩＮが０．０１以下であるかスピン密度が５．０×１０１０（個／ｎｍ＊ｃｍ２）以上であり、前記光学フィルタが、特定の分光特性（ｉｉ－１）～（ｉｉ－３）をすべて満たし、前記高屈折率膜は酸素濃度の最小値が７～３０ａｔｍ％であるシリコン膜である、光学フィルタ。【選択図】図１