# US RE45,541 E1 · Tactile sensor using elastomeric imaging > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US RE45,541 E1 - Document ID: USRE45541E1 - Status: Granted - Kind: E1 - Application number: 14/045,668 - Filed: 2013-10-03 - Granted: 2015-06-02 - Earliest claimed: 2008-06-19 - Assignees: Massachusetts Institute of Technology - Applicants: Massachusetts Institute of Technology - Inventors: Edward Adelson - Web page: https://patentgrep.com/patent/USRE45541E1 ## CPC - G06F 3/042: by opto-electronic means - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A tactile sensor includes a photosensing structure, a volume of elastomer capable of transmitting an image, and a reflective skin covering the volume of elastomer. The reflective skin is illuminated through the volume of elastomer by one or more light sources, and has particles that reflect light incident on the reflective skin from within the volume of elastomer. The reflective skin is geometrically altered in response to pressure applied by an entity touching the reflective skin, the geometrical alteration causing localized changes in the surface normal of the skin and associated localized changes in the amount of light reflected from the reflective skin in the direction of the photosensing structure. The photosensing structure receives a portion of the reflected light in the form of an image, the image indicating one or more features of the entity producing the pressure. ## Claims ### Claim 1 A tactile sensor comprising: a photosensing structure; a volume of elastomer capable of transmitting an image; and a reflective skin covering said volume of elastomer, said reflective skin being illuminated through said volume of elastomer by one or more light sources, said reflective skin having particles that non-directionally reflect light incident on the reflective skin from within the volume of elastomer, said reflective skin being geometrically altered in response to pressure applied by an entity touching said reflective skin, said geometrical alteration causing localized changes in the surface normal of said skin and associated localized changes in the amount of light reflected from said reflective skin in the direction of said photosensing structure; wherein said photosensing structure is positioned to receive a portion of said reflected light in the form of an image, said image indicating one or more features of the entity producing said pressure. ### Claim 2 (depends on 1) The tactile sensor of claim 1, wherein said volume of elastomer comprises silicone rubber, polyurethane, plastisol, thermoplastic elastomer, natural rubber, polyisoprene, polyvinyl chloride or a mixture thereof. ### Claim 3 (depends on 1) The tactile sensor of claim 1, wherein said volume of elastomer comprises a Shore A hardness between 5 and 90. ### Claim 4 (depends on 1) The tactile sensor of claim 1, wherein the volume of elastomer is in the form of a slab. ### Claim 5 (depends on 1) The tactile sensor of claim 1, wherein said photosensing structure comprises a camera. ### Claim 6 (depends on 1) The tactile sensor of claim 1, wherein said photosensing structure comprises an array of sensing elements. ### Claim 7 (depends on 1) The tactile sensor of claim 1, wherein said one or more features comprise roughness of said entity. ### Claim 8 (depends on 1) The tactile sensor of claim 1, wherein said one or more features comprise the location, amplitude, or direction of the applied pressure. ### Claim 9 (depends on 1) The tactile sensor of claim 1, wherein said one or more features comprise the shape, size, or profile of an object producing said pressure. ### Claim 10 (depends on 1) The tactile sensor of claim 1, wherein said one or more features comprise the motion or slip of a surface touching the reflective skin. ### Claim 11 (depends on 1) The tactile sensor of claim 1, wherein the sensor has physical properties that are similar to those of human skin. ### Claim 12 (depends on 1) The tactile sensor of claim 1, wherein the sensor is formed in the shape of a specified object. ### Claim 13 (depends on 1) The tactile sensor of claim 1, wherein the reflective skin is illuminated by two or more light sources of different colors. ### Claim 14 A method of performing tactile sensing, comprising: (a) providing a volume of elastomer capable of transmitting an image; (b) covering the elastomer with a reflective skin having an inner surface facing the elastomer and an outer surface, wherein the reflective skin comprises particles that non-directionally reflect light incident on the inner surface from within the volume of elastomer; (c) illuminating the reflective skin through the volume of elastomer with one or more light sources, wherein at least a portion of the light is reflected by the inner surface of the reflective skin; (d) contacting the outer surface of the reflective skin with an entity, wherein the contact produces pressure that geometrically alters the reflective skin, wherein the alteration causes localized changes in the inner surface of the reflective skin, and wherein the localized changes in the inner surface of the reflective skin cause associated localized changes in the light reflected from the inner surface of the reflective skin; (e) positioning a photosensing structure to receive a portion of the light reflected from the inner surface of the reflective skin in the form of an image indicating one or more features of the entity contacting the outer surface of the reflective skin. ### Claim 15 (depends on 14) The method of claim 14, wherein said volume of elastomer comprises silicone rubber, polyurethane, plastisol, thermoplastic elastomer, natural rubber, polyisoprene, polyvinyl chloride or a mixture thereof. ### Claim 16 (depends on 14) The method off claim 14, wherein said volume of elastomer comprises a Shore A hardness between 5 and 90. ### Claim 17 (depends on 14) The method of claim 14, wherein the volume of elastomer is in the form of a slab. ### Claim 18 (depends on 14) The method of claim 14, wherein said photosensing structure comprises a camera. ### Claim 19 (depends on 14) The method of claim 14, wherein said photosensing structure comprises an array of sensing elements. ### Claim 20 (depends on 14) The method of claim 14, wherein said one or more features comprise roughness of said entity. ### Claim 21 (depends on 14) The method of claim 14, wherein said one or more features comprise the location, amplitude, or direction of the applied pressure. ### Claim 22 (depends on 14) The method of claim 14, wherein said one or more features comprise the shape, size, or profile of an object producing said pressure. ### Claim 23 (depends on 14) The method of claim 14, wherein said one or more features comprise the motion or slip of a surface touching the reflective skin. ### Claim 24 (depends on 14) The method of claim 14, wherein the sensor has physical properties that are similar to those of human skin. ### Claim 25 (depends on 14) The method of claim 14, wherein the sensor is formed in the shape of a specified object. ### Claim 26 (depends on 14) The method of claim 14, wherein the reflective skin is illuminated by two or more light sources of different colors. ### Claim 27 A tactile sensor comprising: a photosensing structure; and a volume of elastomer capable of transmitting an image, the volume of elastomer having a reflective surface, the reflective surface having particles that cause the reflective surface to reflect light incident on the reflective surface from within the volume of elastomer with a directional selectivity ranging from moderately directional to non-directional, the reflective surface being geometrically altered in response to pressure applied by an entity touching the reflective surface, the geometrical alteration causing localized changes in the surface normal of the surface and associated localized changes in the amount of light reflected from the reflective surface in the direction of the photosensing structure; wherein the photosensing structure is positioned to receive a portion of the reflected light in the form of an image, the image indicating one or more features of the entity producing the pressure. ### Claim 28 (depends on 27) The tactile sensor of claim 27, wherein the reflective surface comprises the particles bound to the elastomer. ### Claim 29 (depends on 27) The tactile sensor of claim 27, wherein the reflective surface comprises the particles included in a paint, the paint being applied to the elastomer. ### Claim 30 (depends on 27) The tactile sensor of claim 27, wherein the reflective surface comprises a reflective skin in contact with the elastomer. ### Claim 31 (depends on 30) The tactile sensor of claim 30, wherein the reflective skin is bound to the elastomer. ### Claim 32 (depends on 27) The tactile sensor of claim 27, the particles reflecting light substantially uniformly in all directions, and the particles causing the reflective surface to reflect light substantially non-directionally. ### Claim 33 (depends on 27) The tactile sensor of claim 27, the particles comprising flakes that exhibit at least one of surface roughness, irregular shape, and random alignment relative to each other, and the particles causing the reflective surface to reflect light moderately directionally. ### Claim 34 (depends on 33) The tactile sensor of claim 33, the flakes comprising bronze. ### Claim 35 (depends on 33) The tactile sensor of claim 33, the flakes comprising aluminum. ### Claim 36 (depends on 27) The tactile sensor of claim 27, the particles comprising titanium dioxide. ### Claim 37 A method of performing tactile sensing, comprising: providing a volume of elastomer capable of transmitting an image, the elastomer having a reflective surface having an outer surface, the reflective surface having particles that cause the reflective surface to reflect light incident on the reflective surface from within the volume of elastomer with a directional selectivity ranging from moderately directional to non-directional; illuminating the reflective surface through the volume of elastomer with one or more light sources, wherein at least a portion of the light is reflected by the reflective surface; contacting the outer surface of the reflective surface with an entity, wherein the contact produces pressure that geometrically alters the reflective surface, wherein the alteration causes localized changes in the reflective surface, and wherein the localized changes in the reflective surface cause associated localized changes in the light reflected from the reflective surface; and positioning a photosensing structure to receive a portion of the light reflected from the reflective surface in the form of an image indicating one or more features of the entity contacting the outer surface of the reflective surface. ### Claim 38 (depends on 37) The method of claim 37, wherein the reflective surface comprises the particles bound to the elastomer. ### Claim 39 (depends on 37) The method of claim 37, wherein the reflective surface comprises the particles included in a paint, the paint being applied to the elastomer. ### Claim 40 (depends on 37) The method of claim 37, wherein the reflective surface comprises a reflective skin in contact with the elastomer. ### Claim 41 (depends on 40) The method of claim 40, wherein the reflective skin is bound to the elastomer. ### Claim 42 (depends on 37) The method of claim 37, the particles reflecting light substantially uniformly in all directions, and the particles causing the reflective surface to reflect light substantially non-directionally. ### Claim 43 (depends on 37) The method of claim 37, the particles comprising flakes that exhibit at least one of surface roughness, irregular shape, and random alignment relative to each other, and the particles causing the reflective surface to reflect light moderately directionally. ### Claim 44 (depends on 43) The method of claim 43, the flakes comprising bronze. ### Claim 45 (depends on 43) The method of claim 43, the flakes comprising aluminum. ### Claim 46 (depends on 37) The method of claim 37, the particles comprising titanium dioxide.