# US 9,429,781 B2 · Filter for selective transmission of visible rays and infrared rays using an electrical signal > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,429,781 B2 - Document ID: US9429781B2 - Status: Granted - Kind: B2 - Application number: 13/882,358 - Filed: 2011-10-28 - Published: 2014-03-20 - Granted: 2016-08-30 - Earliest claimed: 2010-10-29 - Assignees: Samsung Electronics Co., Ltd.; Ghent University - Applicants: Seong Jin Kim; Do Kyoon Kim; Kee Chang Lee; Jeroen Beeckman; Albert Theuwissen - Inventors: Seong Jin Kim; Do Kyoon Kim; Kee Chang Lee; Jeroen Beeckman; Albert Theuwissen - Web page: https://patentgrep.com/patent/US9429781B2 ## CPC - G02F 1/1333: Constructional arrangements; {Manufacturing methods}(G02F1/135, G02F1/136 take precedence) - G02F 1/13473: {for wavelength filtering or for colour display without the use of colour mosaic filters} - G02F 1/13475: {in which at least one liquid crystal cell or layer is doped with a pleochroic dye, e.g. GH-LC cell (G02F1/13476 takes precedence)} - H04N 13/207: using a single two-dimensional [2D] image sensor - H04N 13/257: Colour aspects - H04N 13/271: wherein the generated image signals comprise depth maps or disparity maps - H04N 23/11: for generating image signals from visible and infrared light wavelengths - H04N 25/134: {based on three different wavelength filter elements} - G02B 5/208: {for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation} - G02F 1/13342: {Holographic polymer dispersed liquid crystals} - H04N 13/25: using two or more image sensors with different characteristics other than in their location or field of view, e.g. having different resolutions or colour pickup characteristics; using image signals from one sensor to control the characteristics of another sensor - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract Disclosed is a filter for selective transmission of visible rays and infrared rays using an electrical signal. The filter comprises: a first filter for controlling the degree of absorption of visible rays by changing the molecular arrangement in accordance with the control of the electrical signal; and a second filter for controlling the degree of reflection of infrared rays by changing reflectivity in accordance with the control of the electrical signal. ## Claims ### Claim 1 A tunable filter, comprising: a first filter configured to control a degree of absorption of a visible ray by changing a molecular array, based on a control of an electrical signal; and a second filter configured to control a degree of reflection of an infrared (IR) ray by changing a reflectivity, based on the control of the electrical signal, wherein the first filter is configured by a first layer and a second layer each including an LC molecule and a dye molecule, and the molecules included in the first layer and the molecules included in the second layer are disposed vertically to an optical axis of a visible ray. ### Claim 2 (depends on 1) The tunable filter of claim 1, wherein the first filter is configured by at least a single layer including a liquid crystal (LC) molecule and a dye molecule. ### Claim 3 (depends on 1) The tunable filter of claim 1, wherein the first filter is configured to dispose the LC molecule and the dye molecule for a visible ray to be absorbed in the first filter when turned OFF by the electrical signal, and dispose the LC molecule and the dye molecule for a visible ray to be transmitted to the first filter when turned ON by the electrical signal. ### Claim 4 (depends on 1) The tunable filter of claim 1, wherein the first filter is configured to dispose the LC molecule and the dye molecule to be vertical to an optical axis of a visible ray when turned OFF by the electrical signal, and dispose the LC molecule and the dye molecule to be horizontal to a progression direction of a visible ray when turned ON by the electrical signal. ### Claim 5 (depends on 1) The tunable filter of claim 1, wherein the second filter is configured by a layer including an LC molecule and a layer including a polymer molecule. ### Claim 6 (depends on 1) The tunable filter of claim 1, wherein the second filter is configured to change a reflectivity for an IR ray to be reflected to the second filter when turned OFF by the electrical signal, and change a reflectivity for an IR ray to be transmitted to the second filter when turned ON by the electrical signal. ### Claim 7 (depends on 1) The tunable filter of claim 1, wherein the second filter is configured to set a refractive index of a layer including an LC molecule to differ from a refractive index of a layer including a polymer molecule such that the IR ray is reflected to the second filter when turned OFF by the electrical signal, and set a refractive index of a layer including an LC molecule to be identical to a refractive index of a layer including a polymer molecule such that the IR ray is transmitted to the second filter when turned ON by the electrical signal. ### Claim 8 (depends on 1) The tunable filter of claim 1, wherein the second filter represents a Distributed Bragg Reflector (DBR) structure, using an LC molecule and a polymer molecule. ### Claim 9 A camera, comprising: a first filter configured to absorb a visible ray based on a control of an electrical signal; a second filter configured to reflect an infrared (IR) ray based on a control of the electrical signal; and a sensor configured to sense at least one of a color image and a depth image, wherein when sensing the color image, the first filter and the second filter are configured to transmit the visible ray and the second filter is further configured to reflect the IR ray, and wherein when sensing the depth image, the first filter and the second filter are configured to transmit the IR ray and the first filter is further configured to absorb the visible ray. ### Claim 10 (depends on 9) The camera of claim 9, wherein the filter is configured to perform turning ON/OFF of the first filter and the second filter repeatedly, based on the electrical signal, and transmit a visible ray or an IR ray selectively. ### Claim 11 (depends on 9) The camera of claim 9, wherein the filter is configured to turn ON the first filter based on the electrical signal, and turn OFF the second filter to transmit a visible ray for sensing a color image, and turn OFF the first filter based on the electrical signal, and turn ON the second filter to transmit an IR ray for sensing a depth image. ### Claim 12 (depends on 9) The camera of claim 9, wherein the first filter comprises an LC molecule and a dye molecule. ### Claim 13 (depends on 9) The camera of claim 9, wherein the second filter represents a Distributed Bragg Reflector (DBR) structure. ### Claim 14 (depends on 9) The camera of claim 9, wherein the second filter is configured to change a reflectivity of a filter, using an LC molecule and a polymer molecule. ### Claim 15 (depends on 1) The tunable filter of claim 1, wherein the first filter has a guest-host structure which is configured to transmit the visible ray based on the electrical signal. ### Claim 16 (depends on 1) The tunable filter of claim 1, wherein the second filter has a holographic polymer dispersed liquid crystal (HPDLC) structure, which is configured to transmit the infrared (IR) ray based the electrical signal. ### Claim 17 (depends on 15) The tunable filter of claim 15, wherein the second filter has a holographic polymer dispersed liquid crystal (HPDLC) structure, which is configured to transmit the infrared (IR) ray based the electrical signal. ### Claim 18 (depends on 1) The tunable filter of claim 1, wherein the first filter is configured to transmit the visible ray based on the control of the electrical signal to sense a color image during a first time interval; and the second filter configured to transmit the infrared (IR) ray based on the control of the electrical signal to sense a depth image during a second time interval. ### Claim 19 A filter, comprising: a first filter configured to absorb a visible ray by controlling an electrical signal; and a second filter configured to reflect an infrared (IR) ray by controlling the electrical signal, wherein the second filter is configured to set a refractive index of a layer including an LC molecule to differ from a refractive index of a layer including a polymer molecule such that the IR ray is reflected to the second filter when turned OFF by the electrical signal, and set a refractive index of a layer including an LC molecule to be identical to a refractive index of a layer including a polymer molecule such that the IR ray is transmitted to the second filter when turned ON by the electrical signal.