PATENT DOCUMENT

Publication Number: US-9983027-B2
Application Number: US-201615001034-A
Country: US
Kind Code: B2

Title: Proximity sensor module with light reflector

Abstract:
A proximity sensor may be mounted below a display cover layer in an electronic device. The proximity sensor may have a light source that emits light and a detector configured to detect reflections of the emitted light from nearby external objects. The light emitted from the light source may pass through a lens along an axis towards external objects. The light source and the detector may be mounted in a proximity sensor housing having openings that are aligned with the light source and the detector. A reflector may be mounted to the proximity sensor in a configuration that bridges the opening over the light source. The reflector may be formed from a strip of metal or a strip of prism structures. Some of the light from the light source reflects from the reflector at a non-zero angle with respect to the axis and enhances proximity sensor performance.

Claims:
What is claimed is: 
     
       1. Apparatus, comprising:
 a light source and a light detector that form part of a light-based proximity sensor; and 
 optical structures for the light-based proximity sensor, wherein the optical structures include a lens that directs light from the light source along an axis onto an external object, and wherein the optical structures include a reflector that extends over a gap between the lens and the reflector and that reflects a portion of the light from the light source onto the external object at a non-zero angle relative to the axis. 
 
     
     
       2. The apparatus defined in  claim 1  further comprising:
 proximity sensor housing structures in which the light source and the lens are mounted; and 
 a clear bracket that wraps at least partially around the proximity sensor housing structures. 
 
     
     
       3. The apparatus defined in  claim 2 , wherein the reflector is formed from the clear bracket. 
     
     
       4. The apparatus defined in  claim 2  further comprising:
 a metal bracket that wraps at least partially around the proximity sensor housing structures, wherein the metal bracket overlaps the clear bracket on opposing sides of the proximity sensor housing structures. 
 
     
     
       5. The apparatus defined in  claim 4 , wherein the reflector is formed from the metal bracket. 
     
     
       6. The apparatus defined in  claim 1  further comprising:
 a display cover layer that defines a plane, wherein the proximity sensor and the optical structures are mounted beneath the display cover layer, and wherein the axis is substantially orthogonal to the plane. 
 
     
     
       7. The apparatus defined in  claim 6 , wherein the light that is directed along the axis by the lens and the portion of the light that is reflected at the non-zero angle by the reflector pass through the display cover layer onto the external object. 
     
     
       8. The apparatus defined in  claim 6  further comprising:
 a layer of adhesive interposed between the reflector and the display cover layer that attaches the reflector to the adhesive. 
 
     
     
       9. The apparatus defined in  claim 1 , wherein the reflector is configured to reduce crosstalk between the light source and the light detector. 
     
     
       10. An electronic device, comprising:
 an electronic device housing; 
 a display in the electronic device housing; 
 a display cover layer that covers the display; and 
 a proximity sensor mounted under a portion of the display cover layer, wherein the proximity sensor has a light source that emits light, a light detector, a lens, and a reflector that bridges the lens, wherein a first portion of the light passes through the lens and travels along an axis perpendicular to the display cover layer, wherein a second portion of the light reflects off of the reflector and travels away from the axis at a non-zero angle, and wherein the first and second portions of the light are received at the light detector through the display cover layer. 
 
     
     
       11. The electronic device defined in  claim 10 , wherein the reflector is configured to reduce crosstalk between the light source and the light detector. 
     
     
       12. The electronic device defined in  claim 10  further comprising:
 a metal band that at least partially surrounds the proximity sensor. 
 
     
     
       13. The electronic device defined in  claim 12  further comprising a plastic proximity sensor bracket to which the metal proximity sensor bracket is attached, wherein the plastic proximity sensor bracket at least partially surrounds the proximity sensor. 
     
     
       14. The electronic device defined in  claim 13  wherein the reflector comprises a strip of metal formed from the metal band and that extends substantially parallel to a plane defined by the display cover structure. 
     
     
       15. The electronic device defined in  claim 13  wherein the reflector comprises a prism formed from the plastic proximity bracket and that extends substantially parallel to a plane defined by the display cover structure. 
     
     
       16. The electronic device defined in  claim 10 , wherein the first and second portions of the light exit the electronic device through the display cover layer. 
     
     
       17. The electronic device defined in  claim 16 , wherein the first and second portions of the light exit the electronic device onto an object external to the electronic device that reflects the first and second portions of the light to the light detector through the display cover layer. 
     
     
       18. A proximity sensor, comprising:
 a light source; 
 a light detector; 
 a lens through which light from the light source travels along an axis; 
 a housing in which the light source, light detector, and lens are mounted, wherein the housing has an opening that overlaps the lens; and 
 a reflector that extends over the opening, wherein a first portion of the light exits the proximity sensor housing through the opening along the axis and wherein a second portion of the light is reflected by the reflector and exits the proximity sensor housing at an angle to the axis. 
 
     
     
       19. The proximity sensor defined in  claim 18 , wherein the housing has a rectangular perimeter defined by peripheral side surfaces that surround the light source, the light detector, and the lens, the proximity sensor further comprising:
 a plastic member that at least partially surrounds first and second opposing peripheral side surfaces of the housing and a third peripheral side surface of the housing; and 
 a metal member that at least partially surrounds the first and second peripheral side surfaces of the housing and a fourth peripheral side surface of the housing. 
 
     
     
       20. The proximity sensor defined in  claim 19  wherein the housing comprises an upper surface in which the opening is formed and a lower surface opposite the upper surface, and wherein the peripheral side surfaces are substantially perpendicular to the opposing upper and lower surfaces.

Description:
This application is a continuation of U.S. patent application Ser. No. 13/785,852, filed Mar. 5, 2013, which is hereby incorporated by reference herein in its entirety. This application claims the benefit of and claims priority to U.S. patent application Ser. No. 13/785,852, filed Mar. 5, 2013. 
    
    
     BACKGROUND 
     This relates generally to sensors and, more particularly, to proximity sensors for electronic devices. 
     Some cellular telephones contain proximity sensors. A proximity sensor can detect when a cellular telephone has been brought into proximity to a user&#39;s head. When the cellular telephone comes into close proximity to the user&#39;s head, touch screen functions in the cellular telephone can be deactivated to avoid unintentional touch input. 
     A cellular telephone proximity sensor generally contains a light-emitting diode that emits infrared light and a corresponding infrared light sensor that measures the amount of emitted infrared light that is reflected back to the infrared light sensor from the user&#39;s head. In some circumstances, such as when a user&#39;s hair is dark, the amount of reflected light from the user&#39;s head may be relatively small. Unless care is taken, proximity sensor signals will not be sufficiently accurate to properly deactivate a touch screen. 
     It would therefore be desirable to be able to provide improved proximity sensors for electronic devices. 
     SUMMARY 
     A proximity sensor may be mounted below a display cover layer in an electronic device. The proximity sensor may have a light source that emits light and a detector configured to detect reflections of the emitted light from nearby external objects. 
     The light emitted from the light source may pass through optical structures such as a lens and may travel along an axis towards external objects. The lens may collimate the emitted light or produce emitted light with an angular divergence. 
     The light source and the detector may be mounted in a proximity sensor housing having openings that are aligned respectively with the light source and the detector. A reflector may be mounted to the proximity sensor in a configuration that bridges the opening over the light source. 
     The reflector may be formed from a strip of metal, a strip of prism structures, or other structures that direct light in a desired off-axis direction. Light from the light source that reflects from the reflector at a non-zero angle with respect to the axis helps increase reflected signal intensity relative to noise signals and thereby enhances proximity sensor performance. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device with proximity sensor structures in accordance with an embodiment of the present invention. 
         FIG. 2  is a cross-sectional side view of a portion of an electronic device showing where proximity sensor structures and a proximity sensor window for the proximity sensor structures may be formed in accordance with an embodiment of the present invention. 
         FIG. 3  is a cross-sectional side view of a proximity sensor structure in which optical structures are being used to collimate emitted light and reflect light at an angle in accordance with an embodiment of the present invention. 
         FIG. 4  is a cross-sectional side view of a proximity sensor structure having a light source with optical structures that emit light vertically upwards and that direct a portion of emitted light at a non-zero angle with respect to the vertically propagating light in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional side view of a light reflecting structure based on a prism that may be used to direct a portion of emitted light in a proximity sensor at an angle with respect to vertically propagating light in accordance with an embodiment of the present invention. 
         FIG. 6  is a cross-sectional side view of a sawtooth light reflecting structure based on a group of parallel prisms that may be used to direct a portion of emitted light in a proximity sensor at an angle with respect to vertically propagating light in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of a light reflecting structure based on a mirror that may be used to direct a portion of emitted light in a proximity sensor at an angle with respect to vertically propagating light in accordance with an embodiment of the present invention. 
         FIG. 8  is a cross-sectional side view of a mirror that is configured to direct a portion of emitted light in a proximity sensor at a given angle with respect to vertical in accordance with an embodiment of the present invention. 
         FIG. 9  is a graph containing simulation traces that model how a proximity sensor is expected to perform when measuring dark external objects through a potentially smudged display cover layer over a range of deflection angles for a proximity sensor light reflecting structure in accordance with an embodiment of the present invention. 
         FIG. 10  is a perspective view of a portion of a light source with a sawtooth-shaped light reflecting structure in accordance with an embodiment of the present invention. 
         FIG. 11  is a cross-sectional side view of a sawtooth light reflecting member and associated layers of adhesive for mounting the light reflecting structure in a proximity sensor to serve as a light reflecting member in accordance with an embodiment of the present invention. 
         FIG. 12  is a perspective view of a light-based proximity sensor having a light source and light detector mounted within a common housing in accordance with an embodiment of the present invention. 
         FIG. 13  is a perspective view of the light-based proximity sensor structure of  FIG. 12  following attachment of a metal bracket and overmolded plastic structures in accordance with an embodiment of the present invention. 
         FIG. 14  is a cross-sectional side view of an illustrative proximity sensor of the type shown in  FIG. 13  after mounting of the proximity sensor to the underside of a display cover layer in accordance with an embodiment of the present invention. 
         FIG. 15  is a perspective view of a light-based proximity sensor structure having a light source and light detector mounted within a common housing and having a strip of sawtooth reflector structures mounted above the light source to reflect light at an angle from the main axis along which emitted light travels in accordance with an embodiment of the present invention. 
         FIG. 16  is a cross-sectional side view of a portion of an illustrative light-based proximity sensor showing how a strip of sawtooth reflector structures may be used in reflecting light in accordance with an embodiment of the present invention. 
         FIG. 17  is a perspective view of a metal bracket and overmolded plastic structures of the type that may be configured to form a strip-shaped metal reflector for a proximity sensor in accordance with an embodiment of the present invention. 
         FIG. 18  is a cross-sectional side view of a portion of an illustrative light-based proximity sensor showing how a strip of metal of the type shown in  FIG. 17  may be used in reflecting light in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices such as device  10  of  FIG. 1  may be provided with proximity sensor components. The proximity sensor components may include light-based proximity sensor components that can be used to make light-based proximity sensor measurements. Proximity sensor data may be used in controlling the operation of device  10 . For example, proximity sensor data may be used in controlling touch sensor functions and may be used in controlling other device functions. Device  10  may monitor proximity sensor output during operation of a touch screen and other device features. If the proximity sensor output indicates that an external object such as a user&#39;s head is within close proximity to the device, touch sensor functionality may be momentarily deactivated to avoid unintended touch input from the external object. 
     Device  10  of  FIG. 1  may be a portable computer, tablet computer, computer monitor, handheld device, global positioning system equipment, gaming device, cellular telephone, portable computing equipment, or other electronic equipment. 
     Device  10  may include a housing such as housing  12 . Housing  12 , which may sometimes be referred to as a case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of these materials. 
     Housing  12  may be formed using a unibody configuration in which some or all of housing  12  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). 
     In some configurations, housing  12  may be formed using front and rear housing structures that are substantially planar. For example, the rear of device  10  may be formed from a planar housing structure such as a planar glass member, a planar plastic member, a planar metal structure, or other substantially planar structure. The edges (sidewalls) of housing  12  may be straight (vertical) or may be curved (e.g., housing  12  may be provided with sidewalls formed from rounded extensions of a rear planar housing wall). As shown in  FIG. 1 , the front of device  10  may include a planar display such as display  14  that is covered with a planar cover layer. The cover layer that covers the surface of display  14  may be formed from clear glass, clear plastic, or other transparent materials (e.g., materials that are transparent to visible light and that are generally transparent to infrared light). The cover layer that covers display  14  is sometimes referred to as a display cover layer, display cover glass, or plastic display cover layer. 
     Display  14  may, for example, be a touch screen that incorporates capacitive touch electrodes or a touch sensor formed using other types of touch technology (e.g., resistive touch, acoustic touch, force-sensor-based touch, etc.). Display  14  may include image pixels formed from light-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electronic ink elements, liquid crystal display (LCD) components, or other suitable image pixel structures. 
     Display  14  and the cover layer on display  14  may have an active region and an inactive region. Active region  22  of display  14  may lie within rectangular boundary  24 . Within active region  22 , display pixels such as liquid crystal display pixels or organic light-emitting diode display pixels may display images for a user of device  10 . Active display region  22  may be surrounded by an inactive region such as inactive region  26 . Inactive region  26  may have the shape of a rectangular ring surrounding active region  22  and rectangular boundary  24  (as an example). To prevent a user from viewing internal device structures under inactive region  26 , the underside of the cover layer for display  14  may be coated with an opaque masking layer in inactive region  26 . The opaque masking layer may be formed from a layer of ink (e.g., black or white ink or ink of other colors), a layer of plastic, or other suitable opaque masking material. 
     Device  10  may include input-output ports, buttons, sensors, status indicator lights, speakers, microphones, and other input-output components. As shown in  FIG. 1 , for example, device  10  may include one or more openings in inactive region  26  of display  14  to accommodate buttons such as button  16  and may include one or more openings such as speaker port opening  18  to accommodate audio components. 
     Device  10  may include one or more optical components. For example, device  10  may include a light sensor such as visible light sensor that makes measurements on the level of ambient light in the vicinity of device  10 . The optical components may also include a light-based proximity sensor. A proximity sensor of this type may emit light and may detect how much of the emitted light is reflected from external objects. Because more light tends to be reflected when external objects are in close proximity to the proximity sensor, the amount of reflected light that is detected by the proximity sensor may be used to determine whether or not external objects are located within the vicinity of the proximity sensor. 
     A proximity sensor may be mounted on the front or rear surface of device  10 , may be mounted on housing sidewalls, or may be mounted in other suitable device locations. With one illustrative arrangement, which is sometimes described herein as an example, a proximity sensor may be located under a portion of inactive region  26 . The proximity sensor may, for example, be located under region  20  of inactive region  26 . Region  20  may be formed from an opening or other window in inactive region  26 . 
     The proximity sensor may include an infrared light emitter and an infrared light detector. A infrared-transparent material such as “infrared ink” that tends to block visible light while allowing infrared light to pass may be used to cover region  20  (i.e., a proximity sensor window may be formed in region  20  by creating an opening in an opaque masking layer in region  26  and by filling the opening with a layer of infrared-transparent ink). 
     A cross-sectional side view of device  10  in the vicinity of proximity sensor window  20  is shown in  FIG. 2 . As shown in  FIG. 2 , display  14  of device  10  may include display structures that generate images such as display module  30 . Display module  30  may be an organic light-emitting-diode display module, a liquid crystal display module, or other display structures for generating visible images for a user of device  10 . Display module  30  may be mounted within housing  12  (e.g., on the front surface of device  10 ). Display module  30  may, if desired, include a touch sensor array such as a capacitive touch sensor array or a touch sensor formed using other touch technologies. 
     Display module  30  may be covered with a cover layer such as cover layer  48 . Cover layer  48  may be formed from a clear layer of plastic, a clear (transparent) glass layer, or other suitable transparent layer. The underside of cover layer  48  in inactive region  26  may be provided with an opaque masking layer such as opaque masking layer  32 . Opaque masking layer  32  may be formed from a material that is opaque at visible wavelengths such as black ink, black plastic, ink or plastic with other colors (blue, silver, white, etc.), or other suitable opaque material. Opaque masking layer  32  may help block interior device components such as proximity sensor  36  from view through layer  48  by a user of device  10 . In active region  22  of display  14 , cover layer  48  may be free of opaque masking layer material. 
     Proximity sensor window  20  may be formed by creating an opening in opaque masking layer  32  and filling the opening with a layer of material such as infrared ink  34  that is able to block at least some visible light while allowing infrared light to be transmitted. Other types of schemes may be used for mounting proximity sensor  36  within housing  12  if desired. The use of an infrared-light-compatible proximity sensor window in opaque masking layer  32  on the underside of a transparent planar member such as display cover layer  48  is merely illustrative. 
     Proximity sensor  36  may include a light source such as light source  38  and a light detector such as light detector  40 . Light source  38  may be, for example, an infrared light-emitting diode that emits light  42 . Light  42  may pass through proximity sensor window  20  and the material of cover layer  48 . Upon striking the head of a user of device  10  or other external object  46 , light  42  may be reflected off of the object, as shown by reflected light  44  in  FIG. 2 . 
     Reflected light  44  may be detected using a light detector in proximity sensor  36  such as light detector  40 . Light detector  40  may be, for example, a silicon photosensor. By measuring the magnitude of the reflected light signal, proximity sensor  36  may be used to determine whether external object  46  is in the proximity of device  10 . For example, the magnitude of reflected light  44  may be compared to a threshold level or may be otherwise processed to ascertain whether external object  46  is sufficiently close to display  14  to warrant actions such as temporary deactivation of the touch sensor functions of display  14 . 
     Light source  38  and light detector  40  may be housed in a common package (e.g., a housing formed from plastic and/or metal), may be formed from separately packaged devices that are mounted to a common substrate (e.g., a printed circuit substrate formed from a rigid printed circuit board material such as fiberglass-filled epoxy or a flexible printed circuit substrate material such as a sheet of polyimide or other flexible polymer), or may otherwise be mounted within housing  12 . 
     The pattern in which light  42  is emitted from device  10  can affect the performance of sensor  36 . If light  42  diverges too rapidly, the amount of reflected light  44  will tend to be low. Satisfactory reflected light may be obtained when transmitting light  42  in a collimated light beam (i.e., a light beam with parallel rays) or in a slightly diverging beam (e.g., a beam that exhibits an angular spread of less than 40°, less than 20°, or less than 10°). 
       FIG. 3  is a cross-sectional side view of proximity sensor  36  mounted adjacent to display cover layer  48  in an electronic device. As shown in  FIG. 3 , light  42  may be emitted vertically (parallel to axis Z) along vertical axis  52 . Light  42  may travel along axis  52  towards external objects. Axis  52  may serve as a surface normal for the surfaces of display cover glass  48  and may therefore be perpendicular to both the upper and lower surfaces of display cover glass  48 . Light  42  may be emitted in a collimated pattern or may be emitted from light source  38  that emits some of light  42  with an angular spread A that is dictated by the type of light-emitting diode or other component that is used for implementing light source  38  and the optical structures that focus the light from the light-emitting diode (see, e.g., light  42 ′). As an example, portions of light  42  may have an angular spread A of about 0-40° as the light exits light source  38 . 
     Light  42  that is traveling vertically upwards may reflect off of external object  46  and be detected as reflected light  44  by light detector  40 . Skin oils and other surface contaminants  50  may form a coating on the surface of display cover layer  50 . These contaminants may tend to reflect light from light source  38  back into light detector  40  without exiting display cover layer  48  and striking external object  46 . Consider, as an example, light  42 - 1 , which is scattered by surface contaminants  50 . Some of the scattered light such as light ray  42 - 2  will be blocked by portions of proximity sensor housing structure  53  and will not reach light detector  40 . However, other scattered light rays such as scattered light ray  42 - 3  will be received by light detector  40 . 
     Light such as illustrative light  42 - 3  of  FIG. 3  represents a source of crosstalk that degrades proximity sensor performance when present. Increasing the power of emitted light from light source  38  will increase crosstalk from rays such as rays  42 - 3  proportionally, so merely increasing output power will not eliminate this potential source of noise in the proximity sensor. 
     Light source  38  preferably includes light reflecting structures that reflect some of the vertically traveling emitted light along angled paths towards external object  46 . For example, light source  38  may contain optical structures that direct some of light  42  exiting light source  38  vertically in direction Z at an angle 2X with respect to vertical axis Z, as indicated by angled light ray  42 - 4 . Because light  42 - 4  travels at a greater angle through surface contaminant layer  50 , reflections  42 - 4 ′ from this layer fall outside the entrance aperture of light detector  40  as shown in  FIG. 3  and so do not contribute to unwanted crosstalk signals. The portion of light  42 - 4  that is not reflected off of contaminants  50  or the top surface of display cover layer  48  reaches external object  46  and reflects favorably back into the detector as ray  44 . As described in connection with  FIG. 4 , light redirecting features  68  of  FIG. 4  increase the amount of favorable signal compared to a device without such light redirecting features. Angled light  42 - 4  may be characterized by an angular spread of angle B, as shown by light rays  42 ″. 
     Cover layer  48  may lie in the x-y plane. As shown in  FIG. 4 , light source  38  has a lens or other optical structures  64  that may be used to modify the angular spread of light  42 . For example, optical structures  64  may be based on a lens or other structures that collimate light or that otherwise refract or direct light  42 E that is emitted from light-emitting diode  62  within light source  38  to produce emitted light  42 . The light exiting lens  64  may diverge slightly or may be collimated light that propagates substantially parallel to axis  52  as shown in the example of  FIG. 4 . Some of the light exiting lens  64  such as light  42 M may be directed away from vertical axis  52  by optical structures  68  as angled light  42 - 4 . Optical structures  68  may direct light  42 M along the path of ray  42 - 4  by reflection (as an example), so optical structures  68  may sometimes be referred to as light reflecting structures or a reflector. 
     Light  44  that has been reflected from an external object may be received by light sensor  60  through a lens or other optical structure  66  in light detector  40 . Light sensor  60  may be a semiconductor detector such as a silicon photodetector or other light detector device. 
     Axis  52 , which may sometimes be referred to as a vertical axis, may form a surface normal for planar display cover layer  48  and may represent the direction of propagation (propagation axis) of collimated light  42 . The angular deviation of the most divergent light rays in collimated light  42  relative to axis  52  and vertical dimension may be relatively small (i.e., A may be less than 10°, less than 4°, or less than 2° in scenarios in which lens  64  is configured to produce collimated light  42 ). 
     The use of collimated light in detecting the presence of external object  46  may help avoid undesirable detector noise that might otherwise arise due to reflections of light from cover layer  48  into detector  40  (e.g., angled-light reflections from the uppermost glass-air or plastic-air interface associated  48  and from surface contaminants  50 ). The exclusive use of collimated light may, however, result in relatively low signal strength for the reflected light signal, particularly when light  42  strikes a dark external object. 
     In a configuration of the type shown in  FIG. 4 , angled light  42 - 4  serves as an additional source of emitted light for detecting the presence of external objects. The angle of light  42 - 4  may be selected to produce few or no direct reflections from the upper surface of the display cover layer into detector  40  and few or no reflections from surface contaminant layer  50  into detector  40  while increasing reflected light  44  from external object  46  to enhance proximity sensor performance. 
     Reflector  68  may be formed from a prism such as prism  70  of  FIG. 5 . Prism  70  may have a horizontal lower surface through which light  42 M is received, an angled (diagonal) surface such as surface  76  from which light is reflected by the principal of total internal reflection, and a vertical surface such as surface  74  through which reflected light such as light ray  42 - 4  is emitted. Prism  70  may have an elongated shape that runs along axis  80  (into the page in the orientation of  FIG. 5 ). As shown in  FIG. 6 , light reflecting structures  68  may be formed from multiple parallel prisms such as prisms  70 - 1 ,  70 - 2 , and  70 - 3 . These prisms form a sawtooth-shaped structure and are therefore sometimes referred to as forming sawtooth reflection structures or a sawtooth-shaped reflector.  FIG. 7  shows how reflector  68  may be formed by mirror  82 . Mirror  82  may be formed from metal (as an example). 
     As shown in  FIG. 8 , a reflector (mirror  82  in the example of  FIG. 8 ) may be oriented so that reflective surface  86  lies along angled axis  84 . Angled axis  84  and therefore surface  86  of reflector  82  may be oriented at a non-zero angle X with respect to vertical axis  52 . Vertically emitted light  42 M from light source  38  reflects from surface  86  at an angle X, so that reflected light ray  42 - 4  makes an angle 2X with respect to vertical axis  52 . 
     The angle of X between vertical axis  52  and reflector surface  82  and the resulting angle 2X by which angled reflected light ray  42 - 4  deviates from vertical axis  52  may be selected using simulations that model proximity sensor performance. A graph in which sensor performance has been simulated is shown in  FIG. 9 . The  FIG. 9  graph contains four traces. The magnitude of dotted line  90  represents how much crosstalk is generated by rays that are emitted by the light source of a proximity sensor and that are reflected directly into the light detector of the proximity sensor by the surface of the cover glass. As shown by the graph of  FIG. 9 , crosstalk is maximum at about 45°, indicating that this is a poor choice for angle X. The magnitude of dashed-and-dotted line  92  represents the amount of light from the angled light ray that is expected to be reflected from a dark eternal object (e.g., black hair on a user&#39;s head) and detected by the light detector. The signal associated with line  92  is the signal that the proximity sensor is trying to detect in order to determine whether or not the user&#39;s head is in the vicinity of the proximity sensor. The magnitude of dashed line  94  represents the amount of undesired light reflection expected from surface contamination layer  50 . The magnitude of solid line  96  represents a ratio between the undesired smudge signal of line  92  and the desired signal of line  92  (smaller magnitudes of this ratio being better and larger magnitudes being worse). As indicated by line  96 , satisfactory angles X for the reflective surface of mirror  82  or other reflectors  68  relative to vertical axis  52  may have values of about 25° to 35° (in this example). Corresponding angle 2X between angled light  42 - 4  ( FIG. 8 ) and vertical axis  52  may be about 50° to 70°. Other angles may be used for mounting reflector  82  in proximity sensor  36  if desired. 
       FIG. 10  is a perspective view of a portion of a sawtooth-type structure that may be incorporated into a proximity sensor to form reflector  68 . As shown in  FIG. 10 , planar member  10  may have openings such as openings  102  and  104 . Member  100  (e.g., a polymer sheet, a portion of a molded plastic structure, or other structure) may be incorporated into proximity sensor  36  so that opening  102  is aligned with light source  38  and so that opening  104  is aligned with light detector  140 . Prisms  70 - 1 ,  70 - 2 ,  70 - 3 , and  70 - 4  may have elongated shapes that bridge opening  102 . Light that is emitted from light source  38  may pass vertically upwards through opening  102 . Some of the light that is emitted upwards may strike the sawtooth reflector formed by the prisms and may be reflected at an angle, as described in connection with light  42 - 4  of  FIG. 3  and  FIG. 4 , thereby enhancing proximity sensor performance, as described in connection with  FIG. 9 . 
       FIG. 11  is a cross-sectional side view of illustrative proximity sensor member  100  of  FIG. 10  in a configuration in which proximity sensor member  100  has been sandwiched between two layers of adhesive  106 . Adhesive such as adhesive  106  may be used in attaching member  100  and reflector  68  to the top surface of a proximity sensor housing, may be used in attaching member  100  and the rest of proximity sensor  36  to the inner surface of display cover layer  48 , or may otherwise be used in mounting reflector  68  and proximity sensor  36  within device  10 . If desired, the lower layer of adhesive  106  may be omitted (e.g., when forming reflector  68  as part of a plastic member that forms a housing for sensor  36  or that is mounted to a housing for sensor  36 ). 
       FIG. 12  is a perspective view of an illustrative proximity sensor body that may be used for proximity sensor  36 . As shown in  FIG. 12 , proximity sensor body  108  may have the shape of a cube with openings to allow light to exit light source lens  64  and to allow light to enter light detector lens  66 . Proximity sensor body  108  may be formed from one or more structures such as plastic structures (e.g., injection molded plastic structures), metal structures, glass structures, ceramic structures, etc. 
       FIG. 13  is a perspective view of proximity sensor  36  following attachment of additional housing structures to body portion  108  of the proximity sensor housing such as metal band (bracket)  110  and plastic bracket  112  (e.g., a clear plastic bracket). Structures such as structures  110  and  112  may be used in mounting proximity sensor  36  within device  10 . As shown in the cross-sectional side view of  FIG. 14 , for example, adhesive  106  may be used in attaching bracket  112  to the inner surface of display cover layer  48 . 
       FIG. 15  is a perspective view of proximity sensor body  108  in a configuration in which light reflector  68  (e.g., a light reflector formed from a series of parallel prisms such as prisms  70 - 1 ,  70 - 2 , . . . of  FIG. 10 ) bridges a portion of the opening in body  108  that covers light source lens  64 . 
       FIG. 16  is a cross-sectional side view of a portion of proximity sensor  36  in an illustrative configuration in which adhesive  106  has been used in attaching a sawtooth shaped prism-based reflector (reflector  68 ) to the underside of display cover layer  48 . Sawtooth reflector  68  may be formed from a planar plastic member that is attached to the underside of display cover layer  48  with a first layer of adhesive  106  and that is attached to the upper surface of proximity sensor housing member  108  with a second layer of adhesive  106  (see, e.g., sawtooth reflector  68  of  FIG. 11 ) or may be formed as an integral portion of plastic member  112  that is attached to the underside of display cover layer  48  with adhesive  106  (as examples). Other configurations for mounting sawtooth reflector  68  over a portion of lens  64  and the corresponding opening in housing body  108  may be used if desired. The arrangement of  FIG. 16  is merely illustrative. 
       FIG. 17  shows how reflector  68  may be formed from an elongated metal structure such as a strip of metal that is an integral portion of metal bracket  110 . The strip of metal in  FIG. 17  is bent so that its flat surface serves as reflecting surface  86  of reflector  82  in  FIG. 8 . The angle X of the plane of surface  86  with respect to vertical axis  52  may be about 25° to 35° (as an example). 
       FIG. 18  is a cross-sectional side view of a portion of proximity sensor  36  in which reflector  68  has been formed from an integral portion of bracket  110 . Reflector  68  may extend into the page (in the orientation of  FIG. 18 ) so as to bridge lens  64  and the opening in proximity sensor housing  108  that accommodates light from lens  64 . Adhesive  106  may be used in attaching bracket  110  to the underside of display cover layer  48 . 
     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.

Metadata:
Filing Date: 20160119
Publication Date: 20180529
Grant Date: 20180529
Priority Date: 20130305
Inventors: RUH, RICHARD
Assignee: APPLE INC
CPC Classifications: [{"code": "H01L31/125", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1694", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0304", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01D5/26", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01L31/167", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01D5/26", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1694", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0304", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F55/25", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F55/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F55/25", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F55/18", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 51486681