This relates generally to electronic devices and, more particularly, to electronic devices with proximity sensors. Cellular telephones are sometimes provided with proximity sensors. For example, a cellular telephone may be provided with a proximity sensor that is located near an ear speaker on a front face of the cellular telephone.
The front face of the cellular telephone may also contain a touch screen display. The proximity sensor may be used to determine when the cellular telephone is near the head of a user. When not in proximity to the head of the user, the cellular telephone may be placed in a normal mode of operation in which the touch screen display is used to present visual information to the user and in which the touch sensor portion of the touch screen is enabled. In response to determining that the cellular telephone has been brought into the vicinity of the user's head, the display may be disabled to conserve power and the touch sensor on the display may be temporarily disabled to avoid inadvertent touch input from contact between the user's head and the touch sensor.
A proximity sensor for use in a cellular telephone may be based on an infrared light-emitting diode and a corresponding infrared light detector. During operation, the light-emitting diode may emit infrared light outwards from the front face of the cellular telephone. When the cellular telephone is not in the vicinity of a user's head, the infrared light will not be reflected towards the light detector and only small amounts of reflected light will be detected by the light detector. When, however, the cellular telephone is adjacent to the user's head, the emitted light from the infrared light-emitting diode will be reflected from the user's head and detected by the light detector.
Light-based proximity sensors such as these may be used to detect the position of a cellular telephone relative to a user's head but can be challenging to operate accurately. If care is not taken, it can be difficult to determine when a user's head is in the vicinity of the cellular telephone, particularly when a user has hair that is dark and exhibits low reflectivity or when the proximity sensor has become smudged with grease from the skin of the user.
It is within this context that the embodiments herein arise.
An electronic device may be provided with electronic components such as a touch screen display. The touch screen display may be controlled based on information from a proximity sensor. For example, when the proximity sensor indicates that the electronic device is not near the head of a user, the electronic device may be operated in a normal mode in which the display is used to display images and in which the touch sensor functionality of the display is enabled. When the proximity sensor indicates that the electronic device is in the vicinity of the user's head, the electronic device may be operated in a close proximity mode in which display pixels in the display are disabled and in which the touch sensor functionality of the display is disabled.
In accordance with an embodiment, the proximity sensor may be configured to provide near-field measurement results and far-field measurement results. The electronic device may also include processing circuitry that receives the near-field measurement results and the far-field measurement results from the proximity sensor. The processing circuitry selectively enables and disables the touch screen display based on the received near-field measurement results and the far-field measurement results. The near-field measurement results may include a first distance value and a first intensity value, whereas the far-field measurement results include a second distance value and a second intensity value.
The near-field measurement results and the far-field measurement results may be grouped into separate bins so that the near-field measurement results capture information relating to objects located within a predetermined distance from an external surface of the display and so that the far-field measurement results capture information relating to objects located beyond the predetermined distance from the external surface of the display. In general, the electronic device will be configured in close proximity mode by disabling the touch screen display in response to determining that an external object is being brought into close proximity with the electronic device and will be configured in normal mode by enabling the touch screen display in response to determining that an external object is being moved away from the electronic device.
In some embodiments, the processing circuitry may be configured to filter out or ignore the near-field measurement results. For example, the processing circuitry monitors the near-field measurement results to determine when dark objects make physical contact with the display or to determine when smudge is deposited on the display. The processing circuitry may also be configured to detect for sudden changes in the far-field measurement results and/or the near-field measurement results. Operating the electronic and proximity sensor in this way can help minimize the occurrence of false positive events due to smudge and other surface-type contaminants and the occurrence of false negative events due to objects with poor reflectivity.
Further features of the present invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description.
An electronic device may be provided with electronic components such as touch screen displays. The functionality of the electronic device may be controlled based on how far the electronic device is located from external objects such as a user's head. When the electronic device is not in the vicinity of the user's head, for example, the electronic device can be operated in a normal mode in which the touch screen display is enabled. In response to detection of the presence if the user's head in the vicinity of the electronic device, the electronic device may be operated in a mode in which the touch screen is disabled or other appropriate actions are taken.
Disabling touch sensing capabilities from the electronic device when the electronic device is near the user's head may help avoid inadvertent touch input as the touch sensor comes into contact with the user's ear and hair. Disabling display functions in the touch screen display when the electronic device is near the user's head may also help conserve power and reduce user confusion about the status of the display.
An electronic device may use one or more proximity sensors to detect external objects. As an example, an electronic device may use an infrared-light-based proximity sensor to gather proximity data. During operation, proximity data from the proximity sensor may be compared to one or more threshold values. Based on this proximity sensor data analysis, the electronic device can determine whether or not the electronic device is near the user's head and can take appropriate action. A proximity sensor may detect the presence of external objects via optical sensing mechanisms, electrical sensing mechanism, and/or other types of sensing techniques.
An illustrative electronic device that may be provided with a proximity sensor is shown in
As shown in the example of
Display 14 may be a touch screen display that incorporates a layer of conductive capacitive touch sensor electrodes such as electrodes 20 or other touch sensor components (e.g., resistive touch sensor components, acoustic touch sensor components, force-based touch sensor components, light-based touch sensor components, etc.) or may be a display that is not touch-sensitive. Capacitive touch screen electrodes 20 may be formed from an array of indium tin oxide pads or other transparent conductive structures.
Display 14 may include an array of display pixels such as pixels 21 formed from liquid crystal display (LCD) components, an array of electrophoretic display pixels, an array of plasma display pixels, an array of organic light-emitting diode display pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. The brightness of display 14 may be adjustable. For example, display 14 may include a backlight unit formed from a light source such as a lamp or light-emitting diodes that can be used to increase or decrease display backlight levels (e.g., to increase or decrease the brightness of the image produced by display pixels 21) and thereby adjust display brightness. Display 14 may also include organic light-emitting diode pixels or other pixels with adjustable intensities. In this type of display, display brightness can be adjusted by adjusting the intensities of drive signals used to control individual display pixels.
Display 14 may be protected using a display cover layer such as a layer of transparent glass or clear plastic. Openings may be formed in the display cover layer. For example, an opening may be formed in the display cover layer to accommodate a button such as button 16. An opening may also be formed in the display cover layer to accommodate ports such as speaker port 18.
In the center of display 14 (e.g., in the portion of display 14 within rectangular region 22 of
If desired, an opening in the opaque masking layer may be filled with an ink or other material that is transparent to infrared light but opaque to visible light. As an example, light-based proximity sensor 26 may be mounted under this type of opening in the opaque masking layer of the inactive portion of display 14. Light-based proximity sensor 26 may include a light transmitter such as light source 28 and a light sensor such as light detector 30. Light source 28 may be an infrared light-emitting diode and light detector 30 may be a photodetector based on a transistor or photodiode (as examples). During operation, proximity sensor detector 30 may gather light from source 28 that has reflected from nearby objects. Other types of proximity sensor may be used in device 10 if desired. The use of a proximity sensor that includes infrared light transmitters and sensors is merely illustrative.
Proximity sensor 26 may detect when a user's head, a user's fingers, or other external object is in the vicinity of device 10 (e.g., within 10 cm of less of sensor 26, within 5 cm or less of sensor 26, within 1 cm or less of sensor 26, or within other suitable distance of sensor 26).
A schematic diagram of device 10 showing how device 10 may include sensors and other components is shown in
Input-output circuitry 32 may be used to allow data to be supplied to device 10 and to allow data to be provided from device 10 to external devices. Input-output circuitry 32 may include wired and wireless communications circuitry 34. Communications circuitry 34 may include radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, one or more antennas, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications).
Input-output circuitry 32 may include input-output devices 36 such as button 16 of
Sensor circuitry such as sensors 38 of
Sensor data such as proximity sensor data from sensors 38 may be used in controlling the operation of device 10. Device 10 can activate or inactivate display 14, may activate or inactivate touch screen functionality, may activate or inactivate a voice recognition function on device 10, or may take other suitable actions based at least partly on proximity sensor data.
When the proximity sensor data is indicative of a user in close proximity to device 10, device 10 may be operated in a close proximity mode (i.e., state 92). In state 92, device 10 can take actions that are appropriate for scenarios in which device 10 is held adjacent to the head of the user. For example, control circuitry 40 may temporarily disable touch screen functionality in display 14 and/or may disable display 14 (e.g., by turning off display pixel array 21). While operating in state 92, device 10 may use control circuitry 40 to gather and analyze proximity sensor data from proximity sensor 26 to determine whether the user is no longer in close proximity to device 10. When the proximity sensor data is indicative of the absence of a user in close proximity to device 10, device 10 may be placed back into state 90.
The example of
Display structures that are used in forming images for display 14 may be mounted under active region 22 of display 14. Display 14 may include a display stack structure 70 having a backlight unit, light polarizing layers, color filter layers, thin-film transistor (TFT) layers, and other display structures. Display 14 may be implemented using liquid crystal display structures. If desired, display 14 may be implemented using other display technologies. The use of a liquid crystal display is merely illustrative.
The display structures of display 14 may include a touch sensor array such as touch sensor array 60 for providing display 14 with the ability to sense input from an external object such as external object 76 when external object 76 is in the vicinity of a touch sensor on array 60. With one suitable arrangement, touch sensor array 60 may be implemented on a clear dielectric substrate such as a layer of glass or plastic and may include an array of indium tin oxide electrodes or other clear electrodes such as electrodes 62. The electrodes may be used in making capacitive touch sensor measurements.
An opaque masking layer such as opaque masking layer 46 may be provided in inactive region 26. The opaque masking layer may be used to block internal device components from view by a user through peripheral edge portions of clear display cover layer (sometimes referred to as cover glass) 44. The opaque masking layer may be formed from black ink, black plastic, plastic or ink of other colors, metal, or other opaque substances. Windows such as proximity sensor window 48 may be formed in opaque masking layer 46. For example, circular holes or openings with other shapes may be formed in layer 46 to serve as proximity sensor window 48.
At least one proximity sensor 26 may be provided in device 10. As shown in
Display, touch, and sensor circuitry in device 10 may be coupled to circuitry on a substrate such as printed circuit board (PCB) 80. The circuitry on substrate 80 may include integrated circuits and other components (e.g., storage and processing circuitry 30 of
During operation of device 10, optical sensor signals may pass through proximity sensor window 48 for use in detecting the proximity of a user body part. Signals from proximity sensor 26 may be routed to analog-to-digital converter circuitry that is implemented within the silicon substrates from which proximity sensor 26 is formed, to analog-to-digital converter circuitry that is formed in an integrated circuit that is mounted to display stack 70, or to analog-to-digital converter circuitry and/or other control circuitry located elsewhere in device 10 such as one or more integrated circuits in storage and processing circuitry 30 of
If desired, a proximity sensor may be implemented as part of a silicon device that has additional circuitry (i.e., proximity sensor 26 may be implemented as integrated circuits). A proximity sensor with this type of configuration may be provided with built-in analog-to-digital converter circuitry and communications circuitry so that digital sensor signals can be routed to a processor using a serial interface or other digital communications path.
During operation, emitter 100 may emit light 112 outwards from the front face of device 10. When device 10 is not in the vicinity of a user's head, the infrared light will not be reflected towards detector 102 and only small amounts of reflected light will be detected by detector 102. When, however, device 10 is adjacent to the user's head or other nearby object 110, emitted light 112 will be reflected from nearby object 110 and detected by sensor 112 (see, e.g., reflected light 114).
In the exemplary scenario as illustrated in
In an effort to overcome this constraint, time-of-flight (ToF) proximity sensors have been developed that output distance information in addition to the intensity output.
Moreover, neither the intensity reading nor the distance reading output by this type of sensor will be able to accurately detect for the presence of objects with poor reflectivity. It would therefore be desirable to provide improved proximity sensor circuitry that minimizes the chance of false positive and false negative readings.
Conventional proximity sensors only utilize infrared light emission and infrared light detection to sense the proximity of a user's hair, ear, or other body part. The hair of users varies in reflectivity in the infrared light spectrum. Dark (e.g., black) hair tends to absorb infrared light, rather than reflecting infrared light. Dark hair may, for example, reflect less infrared light than skin. As a result, relatively low magnitude infrared-light reflections may be measured when a dark-haired (e.g., black-haired) user places device 10 next to the user's head to make a telephone call. Smudges from finger grease or other contaminants also have the potential to affect proximity sensor readings. When a smudge is present over the proximity sensor, more infrared light will be reflected into light detector 30 than expected.
During operation, care must be taken to avoid false negatives (e.g., situations in which the absorption of light by dark hair makes it erroneously appear as though device 10 is not in the vicinity of the user's head when it is) and false positives (e.g., situations in which the reflection of light from a smudge makes it erroneously appear as though device 10 is in the vicinity of the user's head when it is not).
Proximity sensor 26 may provide outputs Snear and Sfar to host processor 40 (e.g., the storage and processing circuitry described in
For example, some near-field effects such as smudge or grease are deposited directly on the cover glass and tend to be very close to the sensor, whereas other near-field effects such as a user's dark hair held close to the surface of the cover may be relatively farther. Having flexibility in adjusting the near-field versus far-field border enables the device to selectively filter out potentially problematic events. By moving the threshold closer to the exterior surface of the cover glass, the sensor would be better able to focus on the presence of contaminants disposed directly on the cover glass, whereas moving the threshold further way from the surface might allow the sensor to better sense objects that are merely held close to but not on the surface of the cover glass.
For example, the false positive issues associated with smudge and other surface residues can be resolved by simply filtering out or ignoring the near-field readings. In such scenarios, it may be desirable to adjust threshold dth as close to the surface of the cover glass as possible, as indicated by arrows 312. As another example, false negative issues associated with objects of poor reflectivity (e.g., a user with dark hair) can be resolved by closely monitoring the near-field readings to detect for sudden jumps in I1 or d1. In such scenarios, it may be desirable to adjust threshold dth to be slightly above the surface of the cover glass to allow extra margin in the event that the user does not physically press the device to his head. In general, threshold dth may be optimally selected via a cost function analysis to collectively minimize the probability of false positive and false negative events.
At time t1, far-field intensity reading I2 instantaneously drops low, thereby indicating that the external object has at least entered the near-field region, potentially making physical contact with the surface of the cover glass to completely block the proximity sensor's field of view. Meanwhile, near-field intensity reading I1 instantaneously rises high to I11 at time t1, thereby indicating the presence of the external object within the near-field range.
The duration of time from time t1 to time t2 may be equal to the amount of time that the device is held in close proximity with the external object. At time t2, the object may be moved away from the proximity sensor. As a result, far-field intensity reading I2 jumps back to its previous high value but monotonically decreases. Meanwhile, near-field intensity reading I1 drops to a lower value at time t2. In this particular scenario, reading I1 does not drop back down to the original value I10 but rather to an intermediate level I12, which is ΔI1 greater than I10. This gain ΔI1 in the baseline near-field intensity reading may be due to smudge, grease, oil, or other residue left from the user's skin or hair during the period of contact between time t1 and t2. Configuring proximity sensor 26 to separately monitor I1 and I2 in this way can therefore be an effective way of baselining near-field effects such as smudge during normal use case scenarios.
At time t1, far-field intensity reading I2 instantaneously drops low, thereby indicating that the external object has at least entered the near-field region, potentially making physical contact with the surface of the cover glass to completely block the proximity sensor's field of view. Meanwhile, near-field intensity reading I1 instantaneously rises high to I1Y at time t1, thereby indicating the presence of the external object within the near-field range. Note that the rise of ΔI1′ is relatively small but may be nevertheless be sufficient to signify detection of a touchdown event for a poor reflector.
The duration of time from time t1 to time t2 may be equal to the amount of time that the device is held in close proximity with the external object. At time t2, the object may be moved away from the proximity sensor. As a result, far-field intensity reading I2 jumps back to its previous value but monotonically decreases with time. Meanwhile, near-field intensity reading I1 drops to a lower value at time t2. Similar to the scenario in
In yet other suitable embodiments, the proximity sensor can provide an estimate of the object's reflectivity be removing any influence of near-field distance information. By ignoring the near-field signals I1 and d1 and only focusing on the far-field readings I2 and d2, the proximity sensor may simply look for jumps in I2 without regard to any near-field effects. For example, an instantaneous drop in I2 would signify a touchdown event for an object with arbitrary reflectivity, whereas an instantaneous rise in I2 would signify a liftoff even for that object. Operating the proximity sensor in this way may be advantageous since it only needs to monitoring one set of signals instead of having to analyze both near-field and far-field signal components simultaneously.
At step 502, far-field intensity reading I2 may be compared to a predetermined threshold to determine whether I2 is “high” (to indicate a strong far-field presence) or “low” (to indicate that nothing is detected in the sensor's far-field of view. The lack of far-field presence could also potentially be due to an object's poor reflectivity (e.g., from a user's black hair or skin).
Processing may proceed to state 504 if far-field intensity reading I2 is high. At this point, proximity sensor 26 may monitor the far-field distance reading d2 to determine whether d2 has fallen below a trigger threshold value dtrigger. In response to signal d2 falling below threshold value dtrigger, device 10 may be placed in close proximity mode 508-1. As described in connection with
Device 10 may continue operating in mode 508-1 until signal d2 exceeds a release threshold value drelease. In response to signal d2 exceeding value drelease, device 10 may return to normal mode 500, as indicated by path 510. If desired, threshold values dtrigger and drelease may be equal or may be different. In certain embodiments, threshold value dtrigger may actually be less than threshold value drelease to provide a hysteresis mechanism so that inadvertent switching between modes 500 and 508-1 when reading I2 is high would be minimized.
Processing may proceed from step 502 to state 506 if far-field intensity reading I2 is low. In general, near-field intensity reading I1 should be relatively constant in the absence of an external object repeatedly touching the surface of the cover glass of device 10. However, when proximity sensor 26 detects a substantial change in signal I1, device 10 may be placed in close proximity mode 508-2. As described in connection with
Device 10 may continue operating in mode 508-2 until the cumulative intensity reading (i.e., the sum of I1 and I2) falls below a predetermined intensity threshold value Ithreshold. Alternative, only signal I1 may be monitored. As yet another embodiment, distance information d1 and/or d2 may be analyzed. In response to the cumulative intensity reading falling below value Ithreshold, device 10 may return to normal mode 500, as indicated by path 512.
The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. The foregoing embodiments may be implemented individually or in any combination.
This application claims priority to U.S. provisional patent application No. 62/235,149, filed Sep. 30, 2015, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | |
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62235149 | Sep 2015 | US |