# US 2014/0191110 A1 · Proximity Sensors with Smudge Detection Capabilities > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191110 A1 - Document ID: US20140191110A1 - Status: Published application - Kind: A1 - Application number: 13/738,769 - Filed: 2013-01-10 - Published: 2014-07-10 - Earliest claimed: 2013-01-10 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Prashanth S. S. Holenarsipur - Web page: https://patentgrep.com/patent/US20140191110A1 ## CPC - G06F 3/0412: {Digitisers structurally integrated in a display} - G06F 3/03: Arrangements for converting the position or the displacement of a member into a coded form - G06F 3/0421: {by interrupting or reflecting a light beam, e.g. optical touch-screen} - G06F 2203/04101: 2.5D-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 and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract An electronic device may be provided with a touch screen display that is controlled based on information from a proximity sensor attached underneath a display layer. The proximity sensor may have a light source that emits infrared light and a light detector that detects reflected infrared light. When the electronic device is in the vicinity of a user's head, the proximity sensor may produce data indicative of the presence of the user's head. Variations in proximity sensor output due to smudges on the proximity sensor can be detected by providing the proximity sensor with an additional light source. The additional light source may be used to inject light into the display layer. The injected light may be guided within the display layer by total internal reflection. In the presence of smudge, the internally reflecting light may deviate from its normal propagation path. ## Claims ### Claim 1 An electronic device, comprising: a display layer having a surface; a proximity sensor mounted under the display layer, wherein the proximity sensor has a first light source that is configured to emit a first light signal and a light detector configured to receive reflections of the first light signal; and a second light source that is configured to emit a second light signal that travels within the display layer by total internal reflection, wherein the light detector is configured to measure the second light signal to monitor smudges on the surface of the display layer. ### Claim 2 (depends on 1) The electronic device defined in claim 1, further comprising: a touch screen display that is controlled based on measurements gathered using the light detector. ### Claim 3 (depends on 1) The electronic device defined in claim 1, wherein the second light source comprises a laser-based light-emitting diode. ### Claim 4 (depends on 1) The electronic device defined in claim 1, further comprising: light collimating material interposed between the display layer and the proximity sensor, wherein the light collimating material is configured to guide the second light signal into the light detector, and wherein the light collimating material has a refractive index that is greater than that of the display layer. ### Claim 5 (depends on 1) The electronic device defined in claim 1, wherein the display layer includes a notch configured to receive the second light signal from the second light source. ### Claim 6 (depends on 5) The electronic device defined in claim 5, further comprising: material formed in the notch, wherein the material prevents passage of visible light. ### Claim 7 (depends on 1) The electronic device defined in claim 1, wherein the display layer includes a notch positioned over the light detector, and wherein the second light signal exits the display layer into the light detector via the notch. ### Claim 8 (depends on 1) The electronic device defined in claim 1, further comprising: signal processing circuitry configured to receive a sensor output signal from the proximity sensor, wherein the associated signal processing circuitry includes an adjustable filter circuit for performing selective band-pass filtering operations on the sensor output signal, ### Claim 9 A method of operating an electronic device having a display layer, a proximity sensor mounted under the display layer, and a light source, the method comprising: gathering proximity sensor data by emitting first light signals and detecting corresponding reflected light signals with the proximity sensor; and emitting second light signals into the display layer using the light source, wherein the second light signals are guided within the display layer by total internal reflection within the display layer. ### Claim 10 (depends on 9) The method defined in claim 9, wherein the display layer has a surface, the method, further comprising: detecting smudges on the surface of the display layer by measuring the second light signals guided within the display layer. ### Claim 11 (depends on 10) The method defined in claim 10, wherein measuring the second light signals comprises measuring the second light signals guided within the display layer with a light detector in the proximity sensor. ### Claim 12 (depends on 9) The method defined in claim 9, wherein the electronic device further includes a touch screen display and control circuitry, the method, further comprising: with the control circuitry, controlling the touch screen display based on measurements gathered using the proximity sensor. ### Claim 13 (depends on 9) The method defined in claim 9, wherein emitting the first light signals comprises emitting the first light signals having a first frequency, and wherein emitting the second light signals comprises emitting the second light signals having a second frequency that is different than the first frequency. ### Claim 14 (depends on 9) The method defined in claim 9, wherein the display layer has a surface, the method, further comprising: detecting smudges on the surface of the display layer by monitoring for the absence of the second light signals when smudge is present on the surface of the display layer above the proximity sensor. ### Claim 15 (depends on 9) The method defined in claim 9, wherein the display layer has a surface, the method further comprising: detecting smudges on the surface of the display layer by monitoring for the presence of the second light signals when smudge is present on the surface of the display layer above the proximity sensor. ### Claim 16 (depends on 13) The method defined in claim 13, wherein the electronic device further includes signal processing circuitry, the method further comprising: with the proximity sensor, generating an output signal; during a first time period, filtering the output signal by applying band-pass filtering at the first frequency using the signal processing circuitry; and during a second time period, filtering the output signal by applying band-pass filtering at the second frequency using the signal processing circuitry. ### Claim 17 (depends on 13) The method defined in claim 13, wherein the electronic device further includes signal processing circuitry, the method further comprising: with the proximity sensor, generating an output signal; converting the output signal to digital signals with the signal processing circuitry; and performing fast Fourier transform operations on the digital signals. ### Claim 18 A method for operating an electronic device having a display layer, a proximity sensor mounted under the display layer, and a light source, the method comprising: gathering proximity sensor data by emitting first light signals and detecting corresponding reflected first light signals with the proximity sensor; gathering additional data by emitting second light signals with the light source and detecting corresponding reflected second light signals with the proximity sensor; and determining whether an external object is in the vicinity of the electronic device based on the gathered proximity sensor data and the additional data. ### Claim 19 (depends on 18) The method defined in claim 18, wherein emitting the second light signals comprises injecting the second light signals into the display layer so that the second light signals are guided within the display layer by total internal reflection. ### Claim 20 (depends on 19) The method defined in claim 19, wherein emitting the first light signals comprises emitting the first light signals having a first frequency with an additional light source in the proximity sensor, and wherein emitting the second light signals comprises emitting the second light, signals having a second frequency that is different than the first frequency with the fight source. ### Claim 21 (depends on 18) The method, defined, in claim 18, wherein the electronic device further includes another light source and wherein the display layer has a surface, the method further comprising: emitting third light signals with the another light source and detecting corresponding reflected third light signals with the proximity sensor, wherein the second and third light signals are guided within the display layer by total internal reflection, wherein the second light signals strike the surface of the display layer at a first angle of incidence, and wherein the third light signals strike the surface of the display layer at a second angle of incidence that is different than the first angle of incidence.