# US 2014/0191114 A1 · Proximity sensor and method of sensing a distance of an object from a proximity sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191114 A1 - Document ID: US20140191114A1 - Status: Published application - Kind: A1 - Application number: 14/146,175 - Filed: 2014-01-02 - Published: 2014-07-10 - Earliest claimed: 2013-01-09 - Assignees: STMicroelectronics S.r.I. - Applicants: STMICROELECTRONICS S.r.I. - Inventors: Alfio RUSSO; Massimo Cataldo MAZZILLO - Web page: https://patentgrep.com/patent/US20140191114A1 ## CPC - G01S 17/04: Systems determining the presence of a target - G01J 1/44: Electric circuits {(for command of an exposure part G03B7/02)} - G01S 17/08: for measuring distance only (indirect measurement G01S17/46; active triangulation systems G01S17/48) - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) ## Abstract A proximity sensor may include an array of Geiger mode avalanche photodiodes, each including an anode contact and a cathode contact. A common cathode contact may be coupled to the cathode contacts of the array to define a first connection lead at a back side of the array. A common anode collecting grid contact may be coupled to the anode contacts of the array to define a second connection lead of the array. Circuitry may be coupled with the first and second connection leads and configured to sense at least one of a dark current and a rate of current spikes generated in dark conditions, and generate an output signal representing, an estimated distance of an object from the array upon the sensing. ## Claims ### Claim at position 1 1-10. (canceled) ### Claim 11 A proximity sensor comprising: an array of Geiger mode avalanche photodiodes, each Geiger mode avalanche photodiode comprising an anode contact and a cathode contact; a common cathode contact coupled to said cathode contacts of said array of Geiger mode avalanche photodiodes to define a first connection lead at a back side of said array of Geiger mode avalanche photodiodes; a common anode collecting grid contact coupled to said anode contacts of said array of Geiger mode avalanche photodiodes to define a second connection lead of said array of Geiger mode avalanche photodiodes; and circuitry coupled with said first and second connection leads and configured to sense at least one of a dark current and a rate of current spikes generated in dark conditions, and generate an output signal representing an estimated distance of an object from said array of Geiger mode avalanche photodiodes based upon the sensing. ### Claim 12 (depends on 11) The proximity sensor according to claim 11 wherein said circuitry is configured to generate the output signal so that the estimated distance is shorter the greater an increase of the dark current or the greater the rate of current spikes in dark conditions with respect to a functioning condition with said array of Geiger mode avalanche photodiodes far from surrounding objects. ### Claim 13 (depends on 11) The proximity sensor according to claim 11 wherein said circuitry is configured to sense an increase of the dark current and comprises: a current sensor coupled with the first and second connection leads and configured to generate sense signals representing the dark current flowing throughout said array of Geiger mode avalanche photodiodes; and a microcontroller unit coupled with said current sensor and configured to receive the sense signals and generate the output signal corresponding to an increase of the dark current with respect to a functioning condition far from surrounding objects. ### Claim 14 (depends on 13) The proximity sensor according to claim 13 wherein said current sensor comprises: a sense resistor coupled with said array of Geiger mode avalanche photodiodes; and an amplifier coupled to said sense resistor and configured to generate the sense signals as an amplified replica of a voltage on said sense resistor. ### Claim 15 (depends on 11) The proximity sensor according to claim 11 wherein said circuitry is configured to sense an increase of a rate of firing Geiger mode avalanche photodiodes in dark conditions and comprises: a pulse discriminator coupled with the first and second connection leads and configured to generate rectangular pulses representing the current spikes; a counter coupled with said pulse discriminator and configured to count the rectangular pulses representing the current spikes and to generate a corresponding counting of the current spikes; and a microprocessor coupled with said counter and configured to receive the counting and to generate the output signal corresponding to an increase of the rate of current spikes with respect to a functioning condition far from surrounding objects. ### Claim 16 (depends on 11) The proximity sensor according to claim 11 wherein each Geiger mode avalanche photodiode comprises a quenching resistor inserted in an electric path from said anode contact to said cathode contact. ### Claim 17 (depends on 11) The proximity sensor according to claim 11 wherein said array of Geiger mode avalanche photodiodes have a sensing surface; and further comprising a layer of a silicone resin on said sensing surface and having a thickness to define a quarter-wave antireflection layer for photons of infrared light. ### Claim 18 (depends on 11) The proximity sensor according to claim 11 further comprising at least one other array of Geiger mode avalanche photodiodes; and a multiplexer coupled to said array of Geiger mode avalanche photodiodes and said at least one other array of Geiger mode avalanche photodiodes. ### Claim 19 (depends on 11) The proximity sensor according to claim 11 further comprising a plurality of lenses fixed over said array of Geiger mode avalanche photodiodes. ### Claim 20 (depends on 11) The proximity sensor according to claim 11 wherein said array of Geiger mode avalanche photodiodes is integrated on a same silicon substrate. ### Claim 21 A proximity sensor comprising: an array of Geiger mode avalanche photodiodes, each Geiger mode avalanche photodiode comprising an anode contact and a cathode contact; a common cathode contact coupled to said cathode contacts of said array of Geiger mode avalanche photodiodes to define a first connection lead; a common anode contact coupled to said anode contacts of said array of Geiger mode avalanche photodiodes to define a second connection lead; and circuitry coupled with said first and second connection leads and configured to sense a dark current, and generate an output signal representing an estimated distance of an object from said array of Geiger mode avalanche photodiodes based upon, the sensed dark current. ### Claim 22 (depends on 21) The proximity sensor according to claim 21 wherein said circuitry is configured to generate the output signal so that the estimated distance is shorter the greater an increase of the dark current with respect to a functioning condition with said array of Geiger mode avalanche photodiodes far from surrounding objects. ### Claim 23 (depends on 21) The proximity sensor according to claim 21 wherein said circuitry comprises: a current sensor coupled with the first and second connection leads and configured to generate sense signals; and a microcontroller unit coupled with said current sensor and configured to receive the sense signals and generate the output signal corresponding to an increase of the dark current with respect to a functioning condition far from surrounding objects. ### Claim 24 (depends on 23) The proximity sensor according to claim 23 wherein said current sensor comprises: a sense resistor coupled with said array of Geiger mode avalanche photodiodes; and an amplifier coupled to said sense resistor and configured to generate the sense signals as an amplified replica of a voltage on said sense resistor. ### Claim 25 A proximity sensor comprising: an array of Geiger mode avalanche photodiodes, each Geiger mode avalanche photodiode comprising an anode contact and a cathode contact; a common cathode contact coupled to said cathode contacts of said array of Geiger mode avalanche photodiodes to define a first connection lead; a common anode contact coupled to said anode contacts of said array of Geiger mode avalanche photodiodes to define a second connection lead; and circuitry coupled with said first and second connection leads and configured to sense a rate of current spikes generated in dark conditions, and generate an output signal representing an estimated distance of an object from said array of Geiger mode avalanche photodiodes based upon the sensed rate of current spikes. ### Claim 26 (depends on 25) The proximity sensor according to claim 25 wherein said circuitry is configured to generate the output signal so that the estimated distance is shorter the greater the rate of current spikes in dark conditions with respect to a functioning condition with said array of Geiger mode avalanche photodiodes far from surrounding objects. ### Claim 27 (depends on 25) The proximity sensor according to claim 25 wherein said circuitry comprises: a current sensor coupled with the first and second connection leads and configured to generate sense signals; and a microcontroller unit coupled with said current sensor and configured to receive the sense signals and generate the output signal corresponding to an increase in the rate of current spikes with respect to a functioning condition far from surrounding objects. ### Claim 28 (depends on 27) The proximity sensor according to claim 27 wherein said current sensor comprises: a sense resistor coupled with said array of Geiger mode avalanche photodiodes; and an amplifier coupled to said sense resistor and configured to generate the sense signals as an amplified replica of a voltage on said sense resistor. ### Claim 29 (depends on 25) The proximity sensor according to claim 25 wherein said circuitry comprises: a pulse discriminator coupled with the first and second connection leads and configured to generate pulses representing the current spikes; a counter coupled with said pulse discriminator and configured to count the pulses representing the current spikes and to generate a corresponding counting of the current spikes; and a microprocessor coupled with said counter and configured to receive the counting and to generate the output signal corresponding to an increase of the rate of current spikes with respect to a functioning condition far from surrounding objects. ### Claim 30 A method of sensing a distance of an object from a proximity sensor comprising: inversely biasing an array of Geiger mode avalanche photodiodes; sensing at least one of a dark current and a rate of current spikes generated by the array of Geiger mode avalanche photodiodes in dark conditions; and generating an output signal representing an estimated distance of an object from the array based upon the sensing. ### Claim 31 (depends on 30) The method according to claim 30 wherein generating the output signal comprises generating the output signal so that the estimated distance is shorter the greater an increase of the dark current or the greater the rate of current spikes in dark conditions with respect to a functioning condition of the array far from surrounding objects.