# US 2018/0323783 A1 · Proximity sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0323783 A1 - Document ID: US20180323783A1 - Status: Published application - Kind: A1 - Application number: 15/770,290 - Filed: 2016-10-21 - Published: 2018-11-08 - Earliest claimed: 2015-10-22 - Assignees: Elliptic Laboratories AS - Applicants: Elliptic Laboratories AS - Inventors: Hans Jørgen BANG; Ståle A. SKOGSTAD - Web page: https://patentgrep.com/patent/US20180323783A1 ## CPC - H03K 17/945: Proximity switches (H03K17/96 takes precedence) - G01S 7/521: Constructional features - G01S 15/04: Systems determining presence of a target - G01S 15/88: Sonar systems specially adapted for specific applications (seismic or acoustic prospecting or detecting G01V1/00) - G06F 3/043: using propagating acoustic waves - G06F 2203/04108: Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction - 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) - 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 - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract An electronic device (202) includes an ultrasonic proximity sensor arrangement comprising an ultrasonic transmitter (4) and an ultrasonic receiver (6) recessed from a front surface (208) of the device. A barrier (218) extends between the transmitter and receiver in the direction of the front surface of the device. The ultrasonic proximity sensor arrangement is arranged to determine proximity of an object (16) to said front surface based on a signal (214) received by the ultrasonic receiver, wherein the received signal is a reflection from said object of a signal transmitted from the ultrasonic transmitter. ## Claims ### Claim 1 An electronic device having a front surface and including an ultrasonic proximity sensor arrangement comprising: an ultrasonic transmitter recessed from a front surface of the device; and an ultrasonic receiver recessed from the front surface of the device; and a barrier extending between the transmitter and receiver in the direction of the front surface of the device, the ultrasonic proximity sensor arrangement being arranged to determine proximity of an object to said front surface based on a signal received by the ultrasonic receiver, wherein the received signal is a reflection from said object of a signal transmitted from the ultrasonic transmitter. ### Claim 2 (depends on 1) The device as claimed in claim 1 further comprising a gap between the front surface of the device and the barrier. ### Claim 3 (depends on 1) The device as claimed in claim 1, wherein the barrier extends to the front surface of the device. ### Claim 4 (depends on 1) The device as claimed in claim 1, wherein the ultrasonic proximity sensor arrangement is arranged to determine proximity of an object using a measured time of flight between the signal transmitted from the ultrasonic transmitter and the signal received by the ultrasonic receiver after reflection from said object. ### Claim 5 (depends on 1) The device as claimed in claim 1, wherein the ultrasonic proximity sensor arrangement is arranged to determine proximity of an object using a difference between a signal strength of the transmitted signal and a measured signal strength of the received signal. ### Claim 6 (depends on 1) The device as claimed in claim 1, wherein the barrier comprises a solid barrier. ### Claim 7 (depends on 1) The device as claimed in claim 1, wherein the barrier comprises an acoustically attenuating material. ### Claim 8 (depends on 1) The device as claimed in claim 1, wherein the barrier comprises an acoustically absorbent material. ### Claim 9 (depends on 7) The device as claimed in claim 7, wherein said reflected signals have a shorter path through the material than signals that travel from the transmitter to the receiver without being reflected from said object. ### Claim 10 (depends on 1) The device as claimed in claim 1, wherein the receiver is recessed further from the front surface of the device than the transmitter, forming a channel in which the ultrasonic receiver is positioned. ### Claim 11 (depends on 1) The device as claimed in claim 1, wherein the transmitter is recessed further from the front surface of the device than the receiver, forming a channel in which the ultrasonic transmitter is positioned. ### Claim 12 (depends on 10) The device as claimed in claim 10, wherein the channel comprises two discrete signal paths with first and second different lengths, the difference between the first and second lengths being chosen to attenuate direct signals. ### Claim 13 (depends on 10) The device as claimed in claim 10, wherein the channel comprises two discrete signal paths with first and second different lengths, the difference between the first and second lengths being substantially equal to an odd integer multiple of half the wavelength of the signal transmitted from the ultrasonic transmitter. ### Claim 14 (depends on 1) The device as claimed in claim 1, wherein the proximity sensor comprises an acoustically porous layer positioned above the ultrasonic transmitter and the ultrasonic receiver. ### Claim 15 (depends on 14) The device as claimed in claim 14, wherein the acoustically porous layer is flush with the front surface of the device. ### Claim 16 (depends on 14) The device as claimed in claim 14, wherein the acoustically porous layer is recessed from the front surface of the device. ### Claim 17 (depends on 1) The device as claimed in claim 1, wherein the transmitter and receiver are positioned in first and second compartments respectively. ### Claim 18 An electronic device having a front surface and including an ultrasonic proximity sensor arrangement comprising: an ultrasonic transmitter recessed from the front surface; an ultrasonic receiver recessed from the front surface; the ultrasonic proximity sensor arrangement being arranged to determine proximity of an object to said front surface based on a signal received by the ultrasonic receiver, wherein the received signal is a reflection from said object of a signal transmitted from the ultrasonic transmitter; the ultrasonic proximity sensor arrangement further comprising a structure disposed in front of the receiver defining at least first and second discrete signal paths having different path lengths such that signals travelling from the transmitter without passing the front surface to the receiver via the first and second paths undergo a destructive interference which is greater than a destructive interference undergone by signals travelling from the transmitter to the receiver after reflection from the object. ### Claim 19 An electronic device having a front surface and including an ultrasonic proximity sensor arrangement comprising: an ultrasonic transmitter recessed from the front surface; an ultrasonic receiver recessed from the front surface; the ultrasonic proximity sensor arrangement being arranged to determine proximity of an object to said front surface based on a signal received by the ultrasonic receiver, wherein the received signal is a reflection from said object of a signal transmitted from the ultrasonic transmitter; the ultrasonic proximity sensor arrangement further comprising a structure disposed in front of the transmitter defining at least first and second discrete signal paths having different path lengths such that signals travelling from the transmitter without passing the front surface to the receiver via the first and second paths undergo a destructive interference which is greater than a destructive interference undergone by signals travelling from the transmitter to the receiver after reflection from the object. ### Claim 20 (depends on 18) The device as claimed in claim 18 wherein the ultrasonic transmitter is arranged to transmit ultrasonic signals having at least one dominant wavelength and wherein the length of the first path differs from the length of the second path by an odd integer multiple of half of said dominant wavelength. ### Claim 21 A proximity sensor for an electronic device comprising an ultrasonic transmitter and an ultrasonic receiver in a common cavity arranged to determine proximity of an object to a front of said cavity based on a signal received by the ultrasonic receiver, wherein the received signal is a reflection from said object of a signal transmitted from the ultrasonic transmitter wherein the common cavity provides frequency-dependent attenuation to ultrasonic signals transmitted from the ultrasonic transmitter to the ultrasonic receiver with at least one attenuation frequency at which said frequency-dependent attenuation is a maximum within a predetermined frequency range, said ultrasonic signal having at least one dominant frequency substantially equal to said attenuation frequency. ### Claim 22 A method of calibrating a proximity sensor for an electronic device comprising an ultrasonic transmitter and an ultrasonic receiver in a common cavity, the method comprising: transmitting from the ultrasonic transmitter a plurality of ultrasonic test signals of different frequencies; receiving the plurality of ultrasonic test signals at the ultrasonic receiver; and determining from the received plurality of ultrasonic test signals an attenuation frequency corresponding to a maximum attenuation of the associated test signal between the transmitter and the receiver; and configuring said ultrasonic transmitter to transmit a proximity signal having at least one dominant frequency substantially equal to said attenuation frequency to determine proximity of an object to a front of said cavity based a signal received by the ultrasonic receiver, wherein the received signal is a reflection of said proximity signal from said object. ### Claim 23 (depends on 22) The method of claim 22 carried out during regular operation of the device. ### Claim 24 (depends on 22) The method of claim 22 wherein the plurality of test signals are transmitted sequentially. ### Claim 25 (depends on 22) The method as claimed in claim 22 comprising carrying out a frequency sweep.