# US 8,786,436 B2 · Multiple optical axis photoelectric sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,436 B2 - Document ID: US8786436B2 - Status: Granted - Kind: B2 - Application number: 13/203,812 - Filed: 2010-08-25 - Published: 2012-02-09 - Granted: 2014-07-22 - Earliest claimed: 2009-08-31 - Assignees: OMRON Corporation - Applicants: Ryo Kozawa; Kazunori Osako - Inventors: Ryo Kozawa; Kazunori Osako - Web page: https://patentgrep.com/patent/US8786436B2 ## CPC - G01V 8/20: using multiple transmitters or receivers - H03K 17/9629: {using a plurality of detectors, e.g. keyboard} - H03K 17/9631: {using a light source as part of the switch} - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract A multiple optical axis photoelectric sensor is provided that stops a control output according to light being obstructed in a detection area. First and second variable signals indicate the duration of an optical axis scan processing for which light entrance detection and light obstruction detection are obtained, respectively. The first and second variable signals are updated according to results of each scan in the optical axis scan processing. When the value of the first variable reaches a predetermined first reference value, and when a final value of the second variable is equal to or lower than a predetermined second reference value, a notification is made that the light obstruction is detected due to a malfunction. As a result of this notification, whether output signal of the sensor is erroneously switched due to a cause other than an object of a detection target can correctly be made. ## Claims ### Claim 1 A multiple optical axis photoelectric sensor comprising: a projector, an optical receiver, a plurality of optical axes between the projector and the optical receiver, at least one selecting circuit configured to sequentially validate the optical axes, a processor coupled to the at least one selecting circuit for conducting optical axis scan processing of the optical axes, an output for outputting a light state of the photoelectric sensor, and a variable update unit configured to update a first variable and a second variable according to every determination result of the optical axis scan processing, wherein the light state comprises a light entrance state and a light obstruction state, wherein the light state comprises the determination result of a detection area being in the light entrance state or the light obstruction state based on a result of the optical axis scan processing, wherein the first variable is updated while the determination result that the detection area is in the light entrance state is continuously made, and the second variable is updated according to the determination result that the detection area is in the light obstruction state. ### Claim 2 (depends on 1) The photoelectric sensor of claim 1, wherein validation of the optical axes comprises a detection of an existence or non-existence of light entrance of at least one of the optical axes. ### Claim 3 (depends on 1) The photoelectric sensor of claim 1, wherein the processor is configured to determine a light state of the detection area formed by the plurality of optical axes. ### Claim 4 (depends on 1) The photoelectric sensor of claim 1, wherein the output comprises an on-state for the sensor being in the light entrance state and an off-state for the sensor being in the light obstruction state, with the on-state and off-state being selected for output according to the determination result. ### Claim 5 (depends on 1) The photoelectric sensor according to claim 1, further comprising a malfunction notification unit configured to provide notice at the output when the detection area is in the light obstruction state due to a malfunction. ### Claim 6 (depends on 5) The photoelectric sensor of claim 5, further comprising a notification control unit configured to activate the malfunction notification unit when a value of the first variable reaches a predetermined first reference value and when a final value of the second variable is equal to or lower than a predetermined second reference value. ### Claim 7 (depends on 6) The photoelectric sensor according to claim 6, further comprising a malfunction detection result output unit configured to externally output display control information for displaying the detection of a malfunction on a display when the notification control unit activates the malfunction notification unit. ### Claim 8 (depends on 1) The photoelectric sensor according to claim 1, wherein the first variable comprises a first reference value and the second variable comprises a second reference value, and the second reference value is set to a value smaller than that of the first reference value. ### Claim 9 (depends on 1) The photoelectric sensor according to claim 1, wherein the variable update unit is configured to measure a number of times the optical axis scan processing results in a determination that the detection area is in the light entrance state, and a number of times the optical axis scan processing results in a determination that the detection area is in the light obstruction state. ### Claim 10 (depends on 1) The photoelectric sensor according to claim 1, wherein the processor is configured to convert measurement values into a duration of time in updating the first variable and the second variable. ### Claim 11 (depends on 1) The photoelectric sensor of claim 1, wherein the first variable indicates a duration of the optical axis scan processing for which the determination result that the detection area is in the light entrance state is obtained, and the second variable indicates a duration of the optical axis scan processing for which the determination result that the detection area is in the light obstruction state is obtained. ### Claim 12 (depends on 1) The photoelectric sensor according to claim 1, further comprising storage configured to store information on the optical axis scan processing in which the output of a control signal is stopped according to the activation of the malfunction notification unit. ### Claim 13 (depends on 1) The photoelectric sensor according to claim 1, wherein the variable update unit is configured to process measurement of a duration of the optical axis scan processing for which the determination result that the detection area is in the light entrance state is obtained, and a duration of the optical axis scan processing for which the determination result that the detection area is in the light obstruction state is obtained. ### Claim 14 A method for determining a light state of a detection area of a multiple optical axis photoelectric sensor, said detection area comprising a plurality of optical axes between a projector and an optical receiver of the photoelectric sensor, comprising the steps of: validating sequentially the optical axes, conducting a scan processing of the optical axes, detecting an existence or non-existence of light entrance of the validated optical axes, determining a light state of the detection area formed by the optical axes based on a result of the optical axis scan processing, measuring a number of times from the optical axis scan processing in which a result is obtained that the detection area is in a light entrance state, and a number of times from the optical axis scan processing in which a result is obtained that the detection area is in a light obstruction state, switching an output to an on-state or an off-state according to the result of the measuring step, determining if a light state is caused by a malfunction by updating a first variable and a second variable according to every determination result of the optical axis scan processing, and notifying a user when the light state is due to the malfunction, wherein the first variable is updated while the determination result that the detection area is in the light entrance state is continuously made, and the second variable is updated according to the determination result that the detection area is in the light obstruction state. ### Claim 15 A method for determining a light state of a detection area of a multiple optical axis photoelectric sensor, said detection area comprising a plurality of optical axes between a projector and an optical receiver of the photoelectric sensor, comprising the steps of: validating sequentially the optical axes, conducting a scan processing of the optical axes, detecting an existence or non-existence of light entrance of the validated optical axes, determining a light state of the detection area formed by the optical axes based on a result of the optical axis scan processing, measuring a number of times from the optical axis scan processing in which a result is obtained that the detection area is in a light entrance state, and a number of times from the optical axis scan processing in which a result is obtained that the detection area is in a light obstruction state, switching an output to an on-state or an off-state according to the result of the measuring step, determining if a light state is caused by a malfunction by updating a first variable and a second variable according to every determination result of the optical axis scan processing, and notifying a user when the light state is due to the malfunction, wherein the first variable is updated while the determination result that the detection area is in the light obstruction state is continuously made, and the second variable is updated according to the determination result that the detection area is in the light entrance state. ### Claim 16 A multiple optical axis photoelectric sensor comprising: a projector, an optical receiver, a plurality of optical axes between the projector and the optical receiver, at least one selecting circuit configured to sequentially validate the optical axes, a processor coupled to the at least one selecting circuit for conducting optical axis scan processing of the optical axes, an output for outputting a light state of the photoelectric sensor, and a variable update unit configured to update a first variable and a second variable according to every determination result of the optical axis scan processing, wherein the light state comprises a light entrance state and a light obstruction state, wherein the light state comprises a determination result of a detection area being in the light entrance state or the light obstruction state based on a result of the optical axis scan processing, wherein the first variable is updated while the determination result that the detection area is in the light obstruction state is continuously made, and the second variable is updated according to the determination result that the detection area is in the light entrance state. ### Claim 17 (depends on 16) The photoelectric sensor of claim 16, wherein validation of the optical axes comprises a detection of an existence or non-existence of light entrance of at least one of the optical axes. ### Claim 18 (depends on 16) The photoelectric sensor of claim 16, wherein the processor is configured to determine the light state of the detection area formed by the plurality of optical axes. ### Claim 19 (depends on 16) The photoelectric sensor of claim 16, wherein the output comprises an on-state for the sensor being in the light entrance state and an off-state for the sensor being in the light obstruction state, with the on-state and off-state being selected for output according to the determination result. ### Claim 20 (depends on 16) The photoelectric sensor according to claim 16, further comprising a malfunction notification unit configured to provide notice at the output when the detection area is in the light entrance state due to a malfunction. ### Claim 21 (depends on 20) The photoelectric sensor of claim 20, further comprising a notification control unit configured to activate the malfunction notification unit when a value of the first variable reaches a predetermined first reference value and when a final value of the second variable is equal to or lower than a predetermined second reference value. ### Claim 22 (depends on 21) The photoelectric sensor according to claim 21, further comprising a malfunction detection result output unit configured to externally output display control information for displaying the detection of a malfunction on a display when the notification control unit activates the malfunction notification unit. ### Claim 23 (depends on 16) The photoelectric sensor according to claim 16, wherein the first variable comprises a first reference value and the second variable comprises a second reference value, and the second reference value is set to a value smaller than that of the first reference value. ### Claim 24 (depends on 16) The photoelectric sensor according to claim 16, wherein the variable update unit is configured to measure a number of times the optical axis scan processing results in determination that the detection area is in the light entrance state, and a number of times the optical axis scan processing results in the determination that the detection area is in the light obstruction state. ### Claim 25 (depends on 16) The photoelectric sensor according to claim 16, wherein the processor is configured to convert measurement values into a duration of time in updating the first variable and the second variable. ### Claim 26 (depends on 16) The photoelectric sensor of claim 16, wherein the first variable indicates a duration of the optical axis scan processing for which the determination result that the detection area is in the light obstruction state is obtained, and the second variable indicates a duration of the optical axis scan processing for which the determination result that the detection area is in the light entrance state is obtained. ### Claim 27 (depends on 16) The photoelectric sensor according to claim 16, further comprising storage configured to store information on the optical axis scan processing in which the output of a control signal is stopped according to the activation of the malfunction notification unit. ### Claim 28 (depends on 16) The photoelectric sensor according to claim 16, wherein the variable update unit is configured to process measurement of a duration of the optical axis scan processing for which the determination result that the detection area is in the light entrance state is obtained, and a duration of the optical axis scan processing for which the determination result that the detection area is in the light obstruction state is obtained.