# US 11,906,765 B2 · Ultra-thin thin-film optical interference filters > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,765 B2 - Document ID: US11906765B2 - Status: Granted - Kind: B2 - Application number: 16/634,505 - Filed: 2018-08-07 - Published: 2020-07-23 - Granted: 2024-02-20 - Earliest claimed: 2017-08-07 - Applicants: Everix, Inc. - Inventors: Esmaeil Banaei - Web page: https://patentgrep.com/patent/US11906765B2 ## CPC - G02B 5/28: Interference filters - G02B 5/285: {comprising deposited thin solid films (G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361)} - G02B 1/111: using layers comprising organic materials - G02B 1/115: Multilayers - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A thin-film interference filter has a thin-film interference multi-layer stack composed of individual thin-film layers arranged in groups to form a plurality of repeat unit blocks. The thin-film interference filter is flexible enough to be bendable to a radius of curvature of 250 mm or even less without permanently damaging the thin-film interference filter. The thin-film interference filter may have a second thin-film interference multi-layer stack composed of individual thin-film layers arranged in repeat unit blocks may have a different optical transmission spectrum. At least one interlayer between the first thin-film interference multi-layer stack and the second thin-film interference multi-layer stack may block a range of wavelengths of infrared, visible, or ultraviolet light. A defect layer of a different optical thickness than neighboring thin-film layers forming the repeat unit blocks, thereby creating a Fabry Perot resonance cavity. ## Claims ### Claim 1 A thin-film interference filter comprising: a first thin-film interference multi-layer stack composed of individual thin-film layers arranged in groups to form a plurality of first repeat unit blocks; a second thin-film interference multi-layer stack composed of individual thin-film layers arranged in groups to form a plurality of second repeat unit blocks; and at least one interlayer between the first thin-film interference multi-layer stack and the second thin-film interference multi-layer stack, wherein the second thin-film interference multi-layer stack has a different optical transmission spectrum than the first thin-film interference multi-layer stack, wherein the at least one interlayer has a thickness that is 10-1000 times thicker than that of each individual thin-film layer in the first thin-film interference multi-layer stack, wherein the thin-film interference filter is flexible enough to be bendable to a radius of curvature of 250 mm or less without permanently damaging, deforming or cracking the thin-film interference filter as a whole, or the thin-film layers in the at least one multi-layer stack, and wherein the total thickness of the thin-film interference filter is within the range of 0.05 mm to 1 mm. ### Claim 2 (depends on 1) The thin-film interference filter of claim 1, wherein at least one of the at least one interlayer is an absorptive interlayer blocking a range of wavelengths of infrared, visible, or ultraviolet light. ### Claim 3 (depends on 1) The thin-film interference filter of claim 1, comprising: a first jacket layer and a second jacket layer, between which the first thin-film interference multi-layer stack is arranged. ### Claim 4 (depends on 3) The thin-film interference filter of claim 3, further comprising: 1 to 15 layers of anti-reflective thin-film layers on an outside surface of at least one of the first or the second jacket layer. ### Claim 5 (depends on 4) The thin-film interference filter of claim 4, wherein the 1 to 15 layers of anti-reflective thin-film layers are polymeric or glass-based. ### Claim 6 (depends on 4) The thin-film interference filter of claim 4, wherein the 1 to 15 layers of anti-reflective thin-film layers produced by co-drawing with the first jacket layer and the first thin-film interference multi-layer stack in a thermal drawing process. ### Claim 7 (depends on 4) The thin-film interference filter of claim 4, wherein the 1 to 15 layers of anti-reflective thin-film layers produced by coating the first jacket layer after a thermal drawing process. ### Claim 8 (depends on 3) The thin-film interference filter of claim 3, wherein each of the first jacket layer and the second jacket layer have a thickness of 10-1000 times thicker than each individual thin-film layer in the first thin-film interference multi-layer stack. ### Claim 9 (depends on 3) The thin-film interference filter of claim 3, wherein at least one of the first jacket layer or the second jacket layer is an absorptive layer blocking a range of wavelengths of infrared, visible, or ultraviolet light. ### Claim 10 (depends on 1) The thin-film interference filter of claim 1, wherein each individual thin-film layer in the first multi-layer stack has a thickness in the range of 5 nm to 5,000 nm. ### Claim 11 (depends on 1) The thin-film interference filter of claim 1, wherein the thin-film interference filter has a transmission spectrum varying between a low transmission of at most 20% of incident light of a first wavelength and a high transmission of at least 80% of incident light of a second wavelength. ### Claim 12 (depends on 11) The thin-film interference filter of claim 11, wherein the transmission spectrum has at least one transition edge between the low transmission and the high transmission, wherein the transition edge has a width of at most 5% of a third wavelength between the first and the second wavelength, at which the thin-film interference filter transmits 50% of incident light. ### Claim 13 (depends on 1) The thin-film interference filter of claim 1, wherein the thin-film interference filter has a transmission spectrum with at least one transition edge between a high transmission of at least 50% of incident light of a first wavelength and a low transmission of at most 20% of incident light of a second wavelength, wherein the transition edge has a width of at most 5% of the first wavelength, at which the thin-film interference filter transmits 50% of a maximum transmission adjacent the transition edge. ### Claim 14 (depends on 1) The thin-film interference filter of claim 1, further comprising: at least one defect layer of a different optical thickness than immediate neighboring individual thin-film layers forming the repeat unit blocks. ### Claim 15 (depends on 1) The thin-film interference filter of claim 1, wherein at least two of the individual thin-film layers within each of the first repeat unit blocks differ in at least one of a thickness and a refractive index for a specific wavelength. ### Claim 16 (depends on 15) The thin-film interference filter of claim 15, wherein at least two of the individual thin-film layers differ in optical thickness for the specific wavelength defined as a product of the thickness multiplied by the refractive index. ### Claim 17 (depends on 15) The thin-film interference filter of claim 15, wherein the subsequent individual thin-film layers vary in optical thickness or refractive index from each other by small incremental steps to form a quasi-rugate filter with refractive indices of the subsequent thin-film layers following a discrete sinusoidal form. ### Claim 18 (depends on 1) The thin-film interference filter of claim 1, wherein the individual thin-film layers of at least two of the repeat unit blocks are arranged in identical orders of refractive indices. ### Claim 19 (depends on 15) The thin-film interference filter of claim 15, wherein the individual thin-film layers of at least two of the unit blocks are arranged in identical orders of thicknesses, wherein each of the individual thin-film layers of one unit block has a thickness differing from a respective individual thin-film layer of another unit block by a constant scaling factor such that the one unit block differs from the other unit block by the constant scaling factor. ### Claim 20 A thin-film interference filter comprising a first thin-film interference multi-layer stack composed of individual thin-film layers arranged in groups to form a plurality of first repeat unit blocks, wherein the individual thin-film layers of at least two of the repeat unit blocks are arranged in identical orders of refractive indices, wherein the individual thin-film layers of at least two of the unit blocks are arranged in identical orders of thicknesses, wherein each of the individual thin-film layers of one unit block has a thickness differing from a respective individual thin-film layer of another unit block by a constant scaling factor such that the one unit block differs from the other unit block by the constant scaling factor, wherein the thin-film interference filter is flexible enough to be bendable to a radius of curvature of 250 mm or less without permanently damaging, deforming or cracking the thin-film interference filter as a whole, or the thin-film layers in the at least one multi-layer stack, and wherein the total thickness of the thin-film interference filter is within the range of 0.05 mm to 1 mm. ### Claim 21 (depends on 20) The thin-film interference filter of claim 20, wherein the thin-film interference filter has a transmission spectrum varying between a low transmission of at most 20% of incident light of a first wavelength and a high transmission of at least 80% of incident light of a second wavelength, wherein the transmission spectrum has at least one transition edge between the low transmission and the high transmission, and wherein the transition edge has a width of at most 5% of a third wavelength between the first and the second wavelength, at which the thin-film interference filter transmits 50% of incident light. ### Claim 22 (depends on 20) The thin-film interference filter of claim 20, further comprising: a first jacket layer and a second jacket layer, between which the first thin-film interference multi-layer stack is arranged; and 1 to 15 layers of anti-reflective thin-film layers on an outside surface of at least one of the first or the second jacket layer.