# US 5,705,809 A · Optical transducer for measuring acceleration or vibration using a curved light reflector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,705,809 A - Document ID: US5705809A - Status: Granted - Kind: A - Application number: 08/582,186 - Filed: 1996-01-02 - Granted: 1998-01-06 - Earliest claimed: 1996-01-02 - Inventors: Charles H. Kershaw - Web page: https://patentgrep.com/patent/US5705809A ## CPC - G01D 5/30: the beams of light being detected by photocells - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR ## Abstract An optical transducer, wherein the output end of a light transmitting optical fiber or fiber bundle and the input end of a light receiving optical fiber or fiber bundle are fixed angularly adjacent an effective light receiving area of a movable light reflecting member. The light transmitting optical fiber directs a beam of light from a source onto the light reflecting area at a predetermined angle and the light receiving optical fiber is connected with light detection device for receiving at least a portion of the reflected light and detecting the intensity of the reflected light. Upon acceleration or vibration, the movable light reflecting member moves relative to the output and input ends of the optical fibers such that the movement of its effective light reflecting area varies the intensity of the reflected light and the intensity of the reflected light received by the light receiving optical fiber corresponds approximately logarithmically to the amount of movement of the light reflecting member. In a preferred embodiment the light reflecting member is a convex curved mirror surface at the free end of a resilient spring wherein the incident light beam is directed onto a first arcuate segment of the curved surface and, upon movement, the incident light is directed onto a second arcuate segment of the curved surface of different dimension than the first arcuate segment to vary the intensity of the reflected light. ## Claims ### Claim 1 An optical transducer comprising: a movable light reflecting member having an effective light reflecting area on its surface configured to receive a beam of light and form a reflected light; light transmitting means connected with a light source and having an output end fixed angularly adjacent said effective light reflecting area for directing a beam of light onto said light reflecting area at a predetermined angle; light receiving means connected with light detection means and having an input end fixed angularly adjacent said effective light reflecting area at a predetermined angle for receiving at least a portion of said reflected light and detecting the intensity of the reflected light; said light reflecting member being movable relative to said output end of said light transmitting means and said input end of said light receiving means such that the movement of said effective light reflecting area varies the intensity of said reflected light; and the intensity of the reflected light received by said light receiving means corresponds approximately logarithmically to the amount of movement of said light reflecting member. ### Claim 2 (depends on 1) An optical transducer according to claim 1 further comprising: resilient means connected with said movable light reflecting member for moving said light reflecting member in a reciprocating path relative to said output end of said light transmitting means and said input end of said light receiving means such that the total intensity of the reflected light received by said second light guide means corresponds approximately logarithmically to the amount of reciprocal movement of said light reflecting member. ### Claim 3 (depends on 2) An optical transducer according to claim 2 further comprising: said resilient means comprises a spring connected with said movable light reflecting member for moving said light reflecting member along said reciprocating path. ### Claim 4 (depends on 3) An optical transducer according to claim 3 wherein said spring comprises a leaf spring fixed at one end and having a free end connected with said movable light reflecting member for moving said light reflecting member in an arcuate path relative to said output end of said light transmitting means and said input end of said light receiving means such that the total intensity of the reflected light received by said light receiving means corresponds approximately logarithmically to the amount of movement of said light reflecting member. ### Claim 5 (depends on 4) An optical transducer according to claim 4 further comprising: damping means connected with said leaf spring to dampen the response rate of said leaf spring. ### Claim 6 (depends on 5) An optical transducer according to claim 5 wherein said damping means comprises at least one magnet positioned adjacent said leaf spring to dampen the response rate of said leaf spring. ### Claim 7 (depends on 5) An optical transducer according to claim 5 wherein said damping means comprises a viscous fluid surrounding at least a portion of said leaf spring to dampen the response rate of said leaf spring. ### Claim 8 (depends on 1) An optical transducer according to claim 1 wherein said movable light reflecting member has a curved light reflecting area on its surface configured to receive a beam of light and form a reflected light; said light transmitting means output end is fixed angularly adjacent said curved light reflecting area for directing a beam of light onto a first arcuate segment of said curved light reflecting area at a predetermined angle; said light receiving means input end is fixed angularly adjacent said curved light reflecting area at a predetermined angle for receiving at least a portion of said reflected light; said curved light reflecting area is movable relative to said output end of said light transmitting means and said input end of said light receiving means such that upon movement of said light reflecting member, said transmitted beam of light is directed onto a second arcuate segment of said curved light reflecting area of different dimension than said first arcuate segment to vary the intensity of said reflected light; and the intensity of the reflected light received by said light receiving means corresponds approximately logarithmically to the amount of movement of said light reflecting member. ### Claim 9 (depends on 8) An optical transducer according to claim 8 wherein said curved light reflecting area is a convex curved area. ### Claim 10 (depends on 8) An optical transducer according to claim 8 wherein said curved light reflecting area is a concave curved area. ### Claim 11 (depends on 1) An optical transducer according to claim 1 wherein said movable light reflecting member has adjacent straight and curved light reflecting areas on its surface configured to receive a beam of light and form a reflected light; said light transmitting means output end is fixed angularly adjacent said straight and curved light reflecting areas for directing a beam of light onto a first one of said light reflecting areas at a predetermined angle; said light receiving means input end is fixed angularly adjacent said first one of said light reflecting areas at a predetermined angle for receiving at least a portion of said reflected light; said light reflecting member is movable relative to said output end of said light transmitting means and said input end of said light receiving means such that upon movement of said light reflecting member, said transmitted beam of light is directed onto a second one of said light reflecting areas to vary the intensity of said reflected light; and the intensity of the reflected light received by said light receiving means corresponds approximately logarithmically to the amount of movement of said light reflecting member. ### Claim 12 (depends on 1) An optical transducer according to claim 1 wherein said movable light reflecting member is a light reflecting material contained in a transparent tube configured to expose an effective light reflecting area of said material to receive a beam of light and form a reflected light; said light transmitting means output end is fixed angularly adjacent said tube material for directing a beam of light onto said light reflecting area of said material at a predetermined angle; said light receiving means input end is fixed angularly adjacent said tube at a predetermined angle for receiving at least a portion of said reflected light; said light reflecting material is movable relative to said output end of said light transmitting means and said input end of said light receiving means such that the movement of said light reflecting material varies the exposed effective light reflecting area and thereby varies the intensity of said reflected light; and the intensity of the reflected light received by said light receiving means corresponds approximately logarithmically to the amount of movement of said light reflecting material. ### Claim 13 (depends on 12) An optical transducer according to claim 12 further comprising: spring means supporting said movable light reflecting material and moving said light reflecting material relative to said output end of said light transmitting means and said input end of said light receiving means. ### Claim 14 (depends on 13) An optical transducer according to claim 13 wherein said spring means comprises a column of fluid supporting said light reflecting material in said tube and moving said light reflecting material relative to said output end of said light transmitting means and said input end of said light receiving means in response to fluid pressure. ### Claim 15 (depends on 12) An optical transducer according to claim 12 wherein said tube has a curved portion and said movable light reflecting material is contained in an arcuate segment of said tube curved portion to expose a curved effective light reflecting area of said material to receive a beam of light and form a reflected light; said light transmitting means output end is fixed angularly adjacent said tube curved portion for directing a beam of light onto a first arcuate segment of said curved light reflecting area of said material at a predetermined angle; said light receiving means input end is fixed angularly adjacent said tube curved portion at a predetermined angle for receiving at least a portion of said reflected light; said light reflecting material is movable relative to said output end of said light transmitting means and said input end of said light receiving means such that upon movement of said light reflecting material, said transmitted beam of light is directed onto a second arcuate segment of said curved light reflecting area of different dimension than said first arcuate segment to vary the intensity of said reflected light; and the intensity of the reflected light received by said light receiving means corresponds approximately logarithmically to the amount of movement of said light reflecting material. ### Claim 16 (depends on 1) An optical transducer according to claim 1 wherein said light transmitting means comprises an optical fiber having an output end, and said light receiving means comprises an optical fiber having an input end. ### Claim 17 (depends on 16) An optical transducer according to claim 16 wherein said input and output ends of said are each surrounded by a non-reflective tubular member, and the outer ends of each said tubular member is spaced relative to the respective said output and input ends of said optical fibers to confine light rays transmitted or received to the acceptance angle of the respective optical fiber. ### Claim 18 A method of using an optical transducer to determine a sensed condition comprising the steps of: connecting a movable light reflecting member to move in response to a condition to be sensed, said light reflecting member having an effective light reflecting area on its surface configured to receive a beam of light and form a reflected light; transmitting a beam of light through an output end of a light transmitting means angularly onto said effective light reflecting area to form a reflected light; receiving at least a portion of the reflected light through an input end of a light receiving means connected at another end with light detection means for detecting the intensity of the received reflected light; and allowing said reflecting member to move relative to said output end of said light transmitting means and said input end of said light receiving means responsive to the condition being sensed such that the movement of said effective light reflecting area varies the intensity of said reflected light; whereby the detected intensity of the reflected light received by said light receiving means corresponds approximately logarithmically to the amount of movement of said light reflecting member. ### Claim 19 (depends on 18) The method according to claim 18 wherein said movable light reflecting member has a surface shaped to provide a first and a second light reflecting area upon movement thereof; said light transmitting means output end is fixed angularly adjacent a first one of said light reflecting areas for directing a beam of light onto a first one of said light reflecting areas at a predetermined angle; said light receiving means input end is fixed angularly adjacent said first one of said light reflecting areas at a predetermined angle for receiving at least a portion of said reflected light; said light reflecting member is moved relative to said output end of said light transmitting means and said input end of said light receiving means such that upon movement of said light reflecting member, said transmitted beam of light is directed onto a second one of said light reflecting areas to vary the intensity of said reflected light; and the intensity of the reflected light received by said light receiving means corresponds approximately logarithmically to the amount of movement of said light reflecting member. ### Claim 20 (depends on 18) The method according to claim 18 wherein said movable light reflecting member is a light reflecting material contained in a transparent tube configured to expose an effective light reflecting area of said material to receive a beam of light and form a reflected light; said light transmitting means output end is fixed angularly adjacent said tube material for directing a beam of light onto said light reflecting area of said material at a predetermined angle; said light receiving means input end is fixed angularly adjacent said tube at a predetermined angle for receiving at least a portion of said reflected light; and said light reflecting material is moved relative to said output end of said light transmitting means and said input end of said light receiving means such that the movement of said light reflecting material varies the exposed effective light reflecting area and thereby varies the intensity of said reflected light; and the intensity of the reflected light received by said light receiving means corresponds approximately logarithmically to the amount of movement of said light reflecting material.