PATENT DOCUMENT

Publication Number: US-9974180-B2
Application Number: US-201514801686-A
Country: US
Kind Code: B2

Title: Component protection structures for electronic devices

Abstract:
An electronic device may have a printed circuit to which electrical components are mounted. The electrical components may include a thermal sensor and a pressure sensor. A through hole in the printed circuit may receive the shaft of a standoff. The standoff may be soldered to plated metal on the sides of the through hole. A screw or other fastener may secure the printed circuit to a housing for the electronic device. A ring-shaped metal member may be soldered to the printed circuit. The ring-shaped metal member may form a bumper that surrounds the screw or other fastener and the thermal sensor. The pressure sensor may have a port through which ambient pressure measurements are made. A dust protection cover such as a fabric or other porous layer may cover the port.

Claims:
What is claimed is: 
     
       1. Apparatus, comprising:
 a printed circuit having opposing first and second surfaces; 
 a sensor mounted to the first surface of the printed circuit, wherein the sensor extends from the printed circuit board to a first height; 
 a fastener that secures the printed circuit to a support structure, wherein the fastener is separate from the sensor and wherein the support structure is coupled to the second surface of the printed circuit board; and 
 a ring-shaped bumper coupled to the first surface of the printed circuit board that surrounds the sensor and the fastener, wherein the ring-shaped bumper extends from the printed circuit board to a second height that is greater than the first height. 
 
     
     
       2. The apparatus defined in  claim 1  wherein the ring-shaped bumper comprises a metal ring that is soldered to the printed circuit. 
     
     
       3. The apparatus defined in  claim 2  wherein the sensor comprises a thermal sensor. 
     
     
       4. The apparatus defined in  claim 3  wherein the bumper encloses a region of the printed circuit and wherein the apparatus further comprises a pressure sensor mounted to the printed circuit outside of the region. 
     
     
       5. The apparatus defined in  claim 4  wherein the pressure sensor comprises a pressure sensing device mounted in a sensor body in alignment with an opening in the body through which the pressure sensing device senses ambient air pressure. 
     
     
       6. The apparatus defined in  claim 5  further comprising a dust blocking layer that is attached to the sensor body over the opening. 
     
     
       7. The apparatus defined in  claim 6  wherein the dust blocking layer comprises a porous layer selected from the group consisting of: a fabric, a sheet with openings, and an open-celled foam. 
     
     
       8. The apparatus defined in  claim 7  wherein the printed circuit is attached to an electronic device housing using a standoff. 
     
     
       9. The apparatus defined in  claim 8  wherein the printed circuit has opposing first and second surfaces and a through hole that passes between the first and second surfaces, wherein the standoff has a head that is soldered to metal on the first surface, and wherein the standoff has a shaft that is soldered to metal in the through hole. 
     
     
       10. The apparatus defined in  claim 9  wherein the printed circuit comprises a rigid printed circuit board and wherein the thermal sensor is soldered to metal traces on the rigid printed circuit board. 
     
     
       11. The apparatus defined in  claim 10  further comprising a display having light-emitting diodes, wherein the thermal sensor measures heat from the light-emitting diodes through a central opening in the bumper. 
     
     
       12. Apparatus, comprising:
 a housing having an interior; 
 a display mounted in the housing; 
 a printed circuit board mounted within the interior of the housing, wherein the printed circuit board has opposing first and second surfaces; 
 a fastener that secures the printed circuit board to a support structure, wherein the fastener is mounted to the printed circuit board at a first attachment point and wherein the support structure is coupled to the second surface of the printed circuit board; 
 a ring-shaped bumper mounted to the first surface of the printed circuit board, wherein the fastener is surrounded by the ring-shaped bumper and wherein the ring-shaped bumper extends from the printed circuit board to a first height; and 
 a thermal sensor secured to the printed circuit board at a second attachment point that is different from the first attachment point, wherein the thermal sensor is surrounded by the ring-shaped bumper and wherein the thermal sensor extends from the printed circuit board to a second height that is less than the first height. 
 
     
     
       13. The apparatus defined in  claim 12  wherein the ring-shaped bumper is soldered to the printed circuit board. 
     
     
       14. The apparatus defined in  claim 12  wherein the fastener is a first screw. 
     
     
       15. The apparatus defined in  claim 14  wherein the printed circuit board is fastened to the support structure using a second screw. 
     
     
       16. The apparatus defined in  claim 12  further comprising an additional electronic component mounted on the printed circuit board. 
     
     
       17. The apparatus defined in  claim 12  wherein the ring-shaped bumper is a rectangular metal ring that is soldered to a metal trace on the printed circuit board. 
     
     
       18. The apparatus defined in  claim 12  wherein the ring-shaped bumper comprises plastic and wherein the ring-shaped bumper is attached to the printed circuit board using an adhesive. 
     
     
       19. The apparatus defined in  claim 12  wherein the ring-shaped bumper comprises an opening and wherein the thermal sensor is located in the opening.

Description:
This application claims the benefit of provisional patent application No. 62/045,386 filed on Sep. 3, 2014, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This relates generally to electronic devices, and, more particularly, electronic devices that include electrical components. 
     Electronic devices include electronic components such as integrated circuits, sensors, and other circuitry. Electronic components may be mounted on printed circuit boards. A printed circuit hoard may be attached to a device housing using screws. 
     If care is not taken, components can be damaged during use of an electronic device. Components may be bumped during assembly. During use of a device, drop events and other activities may impart stresses on device components and printed circuit boards. Dust particles may become dislodged within the interior of a device or may intrude into the device through a connector port. In the presence of contaminants and stress, there is a risk that device components might not perform satisfactorily and that components and printed circuits might become damaged. 
     It would therefore be desirable to be able to provide improved electronic device structures for protecting printed circuits and components mounted to printed circuits. 
     SUMMARY 
     An electronic device may have a housing with an interior. A display may be mounted to the housing. A printed circuit may be mounted in the interior of the housing. Electrical components may be mounted to the printed circuit. The electrical components may include a thermal sensor, a pressure sensor, integrated circuits, and other circuitry. 
     A through hole in the printed circuit may receive the shaft of a standoff. The standoff shaft may be soldered to plated metal on the sides of the through hole. A screw or other fastener may pass through an opening in the standoff to secure the standoff and the printed circuit to the electronic device housing or other support structure within the electronic device. 
     A screw or other fastener in the vicinity of the thermal sensor may secure the printed circuit to the housing using the standoff or a through hole in the printed circuit board. A ring-shaped metal member may be soldered to the printed circuit. The ring-shaped metal member may form a bumper that surrounds the screw and the thermal sensor to help stiffen the printed circuit in the vicinity of the thermal sensor. 
     The pressure sensor may have a port through which ambient pressure measurements are made. A dust protection cover such as a fabric or other porous layer may cover the port. A ring of adhesive may attach the fabric to a body portion of the pressure sensor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative electronic device in accordance with an embodiment. 
         FIG. 2  is a cross-sectional side view of an illustrative electronic device in accordance with an embodiment. 
         FIG. 3  is a side view of an illustrative electronic device during assembly in accordance with an embodiment. 
         FIG. 4  is a top interior view of a portion of an electronic device in accordance with an embodiment. 
         FIG. 5  is a cross-sectional side view of a portion of the electronic device of  FIG. 4  in accordance with an embodiment. 
         FIG. 6  is a cross-sectional side view of an illustrative electrical component with a porous port cover in accordance with an embodiment. 
         FIG. 7  is an exploded perspective view of an illustrative electronic component with a porous port cover in accordance with an embodiment. 
         FIG. 8  is an assembled perspective view of the illustrative electronic component of  FIG. 7  in accordance with an embodiment. 
         FIG. 9  is a perspective view of an illustrative electronic component with a porous port cover formed from a cluster of perforations such as laser-drilled holes in accordance with an embodiment. 
         FIG. 10  is an interior view of the cluster of perforations of  FIG. 9  in accordance with an embodiment. 
         FIG. 11  is an interior view of the cluster of perforations of  FIG. 9  formed in a structure with a locally thinned portion overlapping the cluster in accordance with an embodiment. 
         FIG. 12  is a cross-sectional side view of an illustrative electronic component with perforations of the type shown in  FIG. 9  in accordance with an embodiment. 
         FIG. 13  is an exploded perspective view of an illustrative electronic component with a port cover structure formed from foam in accordance with an embodiment. 
         FIG. 14  is an assembled perspective view of the illustrative electronic component of  FIG. 13  in accordance with an embodiment. 
         FIG. 15  is a cross-sectional side view of an illustrative standoff of the type that may be used in securing a printed circuit in an electronic device housing in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An illustrative electronic device is shown in  FIG. 1 . Electronic device  10  may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, equipment that implements the functionality of two or more of these devices, or other electronic equipment. 
     As shown in  FIG. 1 , electronic device  10  may have control circuitry  16 . Control circuitry  16  may include storage and processing circuitry for supporting the operation of device  10 . The storage and processing circuitry may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in control circuitry  16  may be used to control the operation of device  10 . The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors and other wireless communications circuits, power management units, audio chips, application specific integrated circuits, etc. 
     Input-output circuitry in device  10  such as input-output devices  18  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 devices  18  may include buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, speakers, tone generators, vibrators, cameras, sensors such as touch sensors, proximity sensors, ambient light sensors, compasses, gyroscopes, accelerometers, light-emitting diodes and other status indicators, data ports, etc. A user can control the operation of device  10  by supplying commands through input-output devices  18  and may receive status information and other output from device  10  using the output resources of input-output devices  18 . 
     Input-output devices  18  may include one or more displays. Device  10  may, for example, include a touch screen display that includes a touch sensor for gathering touch input from a user or a display that is insensitive to touch. A touch sensor for a display in device  10  may be based on an array of capacitive touch sensor electrodes, acoustic touch sensor structures, resistive touch components, force-based touch sensor structures, a light-based touch sensor, or other suitable touch sensor arrangements. 
     Power for device  10  may be provided by an external source of power and/or an internal battery. The components for device  10  such as circuitry  16  and devices  18  and other structures in device  10  may be implemented using integrated circuits, discrete components (e.g., resistors, capacitors, inductors), microelectromechanical systems (MEMS) devices, portions of housing structures, packaged parts, and other devices and structures. 
     Control circuitry  16  may be used to run software on device  10  such as operating system code and applications. During operation of device  10 , the software running on control circuitry  16  may display images for a user on one or more displays and may use other internal components such as input-output devices  18 . Device  10  may use communications circuits to send and receive wireless and wired data. For example, device  10  may use light-emitting components to transmit data and may use light-receiving components to receive transmitted light signals. Device  10  may also use light-emitting, components, light-receiving components, audio components, capacitive sensors, microelectromechanical systems devices, and other components as sensors and output devices. Device  10  may use wireless circuits in circuitry  16  (e.g., a baseband processor and associated radio-frequency transceiver circuitry) to transmit and receive wireless signals. For example, device  10  may transmit and receive cellular telephone signals and/or wireless local area network signals or other wireless data. 
     A cross-sectional side view of art illustrative electronic device is shown in  FIG. 2 . As shown in  FIG. 2 , device  10  may have a housing such as housing  12 . Housing  12 , which may sometimes be referred to as an enclosure or case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more 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.). Device  10  may have inner housing structures that provide additional structural support to device  10  and/or that serve as mounting platforms for printed circuits and other structures. Structural internal housing members may sometimes be referred to as housing structures and may be considered to form part of housing  12 . 
     Device  10  may have a display such as display  14 . Display  14  may be a touch screen display that incorporates a layer of conductive capacitive touch sensor electrodes 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 may be formed from an array of indium tin oxide pads or other transparent conductive structures. 
     Display  14  of device  10  may be formed from a display module such as display module  22  mounted under a cover layer such as display cover layer  20  (as an example). Display  14  (display module  22 ) may be a liquid crystal display, an organic light-emitting diode display, a plasma display, an electrophoretic display, a display that is insensitive to touch, a touch sensitive display that incorporates and array of capacitive touch sensor electrodes or other touch sensor structures or may be any other type of suitable display. Display cover layer  20  may be planar or curved and may be formed from clear glass, a transparent plastic member, a transparent crystalline member such as a sapphire layer, clear ceramics, other transparent materials, or combinations of these structures. 
     Electrical components  26  may be mounted within the interior of housing  12 . Components  26  may be mounted to printed circuits such as printed circuit  24  within the interior of housing  12 . Printed circuit  24  may be a rigid printed circuit board (e.g., a printed circuit hoard formed from fiberglass-filled epoxy or other rigid printed circuit board material) or may be a flexible printed circuit (e.g., a printed circuit firmed from a sheet of polyimide or other flexible polymer layer). Patterned metal traces within printed circuit board  24  may be used to form signal paths between components  26 . If desired, components such as connectors may be mounted to printed circuit  24 . As shown in  FIG. 2 , for example, a cable such as flexible printed circuit cable  28  may couple display module  22  to connector  30 . Connector  30  may couple cable  28  to traces within printed circuit  24 . When coupled as shown in  FIG. 2 , signals associated with operation of display  14  may pass to display module  22  from signal lines in printed circuit  24  through cable  28  and connector  30 . 
     There is sometimes a risk of component damage during device assembly. Consider, as an example, the illustrative configuration for device  10  that is shown in  FIG. 3 . In the arrangement of  FIG. 3 , device  10  has a housing such as housing  12  into which display  14  is being mounted. Electrical components may be mounted to printed circuit  24 . For example, thermal sensor  38  may be mounted to printed circuit board  24 . During normal operation of device  10 , thermal sensor  38  may monitor the temperature of adjacent components such as light-emitting diodes  22  in a backlight unit in liquid crystal display module  22 . Light-emitting diodes  22 ′ may be used to supply backlight for the liquid crystal display module or other display module  22  in display  14 . Sensor  38  may be a solid state sensor or other temperature sensor. 
     For satisfactory performance, it may be desirable to leave a component such as thermal sensor  38  uncovered. By foregoing a cover for sensor  38 , sensor  38  may be used to accurately sense the temperature of adjacent component  22 ′. The presence of intervening structures between sensor  38  and component  22 ′ might prevent heat generated by component  22 ′ from reaching sensor  38 . 
     In a configuration in which sensor  38  is not covered, there is a potential that sensor  38  may be bumped during device assembly. In a configuration of the type shown in  FIG. 3 , a display assembly containing display  14  may be installed within housing  12  by attaching end  36  to housing  12  and then rotating end  34  of display  14  into housing  12  in direction  32  (where screws may be used to finish the assembly process). During this process, portions of the display assembly (e.g., portions near end  36 ) may potentially bump into sensor  38  and damage sensor  38 . For example, sensor  38  may be damaged or sensor  38  may be dislodged from printed circuit  24 . 
     To prevent damage to sensor  38 , a ring-shaped member such as bumper  46  of  FIG. 4  may surround sensor  38 . Bumper  46  may be formed from metal or other suitable materials (e.g., plastic, glass, ceramic, an insulator covered with metal, combinations of these materials, etc.). As an example, bumper  46  may be a rectangular metal ring that is soldered to a metal trace on printed circuit  24  to attach bumper  46  to printed circuit  24 . Ring-shaped bumpers inlay also be formed from other materials (e.g., plastic attached to printed circuit  24  using adhesive, screws or other fasteners, etc.). 
     Printed circuit  24  may have a shape that accommodates nearby components such as component  40 . Sensor  38  may be mounted in region  24  of printed circuit  24 . Additional components such as component  48  may be mounted in portions of printed circuit  24  such as portion  24 ″. Component  48  may be a sensor such as a pressure sensor that makes ambient an pressure measurements of the an within the interior of device  10  and thus the surrounding atmosphere or may be any other electronic component  26 . 
     Component  40  may be an audio component such as a speaker that operates through an opening in housing  12 . Thermal sensor  38  may be mounted near component  40  at the end of housing  12  (e.g., under light-emitting diodes  22 ′ of  FIG. 4 ). Due to space constraints (e.g., the desired to mount printed circuit  24  in the vicinity of light-emitting diodes  22 ′. While accommodating speaker  40 ), the width W of printed circuit portion  24 ′ may be relatively small in the vicinity of thermal sensor  38 . Printed circuit  24  may be secured to housing  12  using screws such as screws  42  and  44  or other fasteners. Because printed circuit  24  may be relatively narrow in region  24 ′ between screws  42  and  44 , there may be a risk that printed circuit  24  will flex at points midway between screws  42  and  44  when stressed (e.g., during a drop event or other unexpected impact on device  10 ), even when printed circuit  24  is formed from a rigid printed circuit board material. 
     In the absence of bumper  46 , flexing of printed circuit  24  could dislodge sensor  38  or cause other damage. In the presence of bumper  46 , however, printed circuit  24  will be locally stiffened. This can strengthen printed circuit  24  in the vicinity of sensor  38  and help prevent sensor  38  from becoming dislodged. Stiffening of portion  24 ′ of printed circuit  24  may be enhanced by laterally extending bumper  46  sufficiently to surround both thermal sensor  38  and printed circuit mounting structures such as screw  42 , as shown in  FIG. 4 . Because screw  42  is attached to housing  12  or other sturdy support structure, printed circuit  24  will be stiff in the vicinity of screw  42 . Bumper  46  helps extend this region of stiffness from screw  42  to the vicinity of sensor  38 . If desired, bumper  46  may have a central opening that encompasses a region of primed circuit board  24  that contains multiple housing attachment points (e.g., screw  44  in additional to screw  4 ). The configuration of  FIG. 4  in which bumper  46  surrounds a single attachment point (screw  42 ) and sensor  38  is merely illustrative. 
       FIG. 5  is a cross-sectional side view of printed circuit  24  of  FIG. 4  taken along line  50  and viewed in direction  52 . As shown in  FIG. 5 , printed circuit  24  may be mounted to a support structure such as housing  12  using screws such as screws  42  and  44  or other fasteners. Bumper  46 , which may be mounted to metal traces (pads) on printed circuit  24  such as metal traces  54  using solder  56  may have an L-shaped cross-sectional shape or other suitable shape. Bumper  46  preferably has a height H 1  above the upper surface of printed circuit  24  that is greater than the height H 2  of sensor  38 . When a portion of display  14  or other structures in device  10  are being inserted into housing  12  in the vicinity of sensor  38 , the relatively tall height of bumper  46  can help prevent the display or other structures from contacting sensor  38 . Opening  47  in the center of bumper  46  allows heat to be received by temperature sensor  38  during operation (e.g., heat from light-emitting diodes  22 ′). 
     If desired, bumper  46  may be formed from multiple segments of material (e.g., two segments, three segments, etc.). In this type of configuration, bumper  46  may still surround and protect sensor  38 , but will not transmit as much stillness from the vicinity of screw  42  to the vicinity of sensor  38  as generally takes place when bumper  46  is formed from a single continuous ring of metal. To enhance stiffness further, a stiffening sheet may be attached to the lower surface of printed circuit  24  under sensor  38 . Bumper  46  and other structures that are solder to printed circuit  24  may be formed from solder compatible materials (e.g., nickel plated stainless steel, etc.). 
     A cross-sectional side view of an illustrative component such as component  48  in region  24 ″ of printed circuit  24  or other portion of printed circuit  24  is shown in  FIG. 6 . Component  48  may be a pressure sensor (e.g., a pressure sensor used as part of an altimeter or other device) or other internal electrical component that has a port such as port  70 . During operation of device  10 , there may sometimes be a risk of contaminants such as dust particles. These particles may be received from the exterior of device  10  (e.g., through an audio port or other port in housing  12 ) or may be generated internally (e.g., when internal parts rub against each other during normal use or during a drop event). Component  48  may be protected from dust particles using a porous layer such as porous port cover  74 . 
     As shown in  FIG. 6 , sensor  48  may have contacts such as contacts  64  (e.g., positive and negative signal terminals, etc.). Contacts  64  may be soldered to metal traces  60  on printed circuit  24  using solder  62 . Pressure sensor  48  may contain a pressure sensing device such as device  68  mounted in pressure sensor body  66  (e.g., a plastic package). Device  68  may be formed from a microelectromechanical systems (MEMS) device such as a micromachined silicon pressure sensing device. Pressure sensing device  68  may be mounted in enclosure  66 . Enclosure  66 , which may sometimes be referred to as a housing, body, package, or case, may be formed from a single structure or multiple structures. Materials such as plastic, metal, ceramic, and glass may be used in forming one or more structures in enclosure  66 . Enclosure  66  may be a surface mount technology package or other suitable enclosure. 
     Enclosure  66  may have one or more openings to the air surrounding enclosure  66  forming a port for pressure sensor  48 , port  70  may be aligned with pressure sensing device  68 . This allows device  68  to be exposed to the surrounding environment so that pressure measurements may be obtained. Pressure sensor  48  may, for example, make ambient pressure sensor measurements through port  70  using pressure sensing device  68 . 
     To prevent dust or other contaminants from entering port  70 , port  70  may include porous material  74 . For example, a layer of porous material  74  may cover enclosure  66  and device  68  (i.e., port  70  may be covered with porous material). Porous material  74  may be a fabric having fibers  76 , may be an open cell plastic foam, may be a layer of metal or polymer in which openings have been formed using chemical etching, laser etching, machining, or other techniques, or may be other porous layer of material. As shown in  FIG. 6  porous layer  74  may have pores (microscopic openings) such as pore  78 . Pores  78  may be sufficiently large to allow air pressure changes to be readily conveyed to pressure sensing device  68  through port  70  while simultaneously being sufficiently small to block dust particles and thereby prevent contaminants from entering port  70 . As an example, pores  78  may have diameters of greater than 5 microns, greater than 10 microns, 5-20 microns, less than 25 microns, less than 50 microns, etc.). 
     Porous layer  72  serves as a dust blocking layer and therefore may sometimes be referred to as a port cover, dust blocking port cover, or dust blocking port structure. Porous layer  72  may be attached to enclosure  66  or may be formed as an integral portion of some or all of the structures of enclosure  66 . 
     As shown in  FIG. 6 , adhesive  72  may, if desired, be used to attach porous layer  74  to enclosure (body)  66  of sensor  48 . Port  70  may have an opening that is circular or rectangular or that has other opening shapes. Adhesive  72  may have a ring shape that surrounds port  70 . For example, adhesive  72  may have the shape of a circular ring, a rectangular ring, a rectangular patch with a circular opening for port  70 , or other ring shape. By surrounding opening  70 , adhesive  72  may help ensure that a satisfactory seal is provided between porous layer  72  and body  66  of sensor  48  around the periphery of layer  72 . Other attachment mechanisms may be used for attaching dust blocking port covers such as porous layer  74  if desired. For example, screws, springs, clamping structures, or other attachment mechanisms may be used to attach porous layer  72  to body  66 . 
     A perspective view of pressure sensor  48  in an illustrative configuration in which adhesive  72  has a rectangular shape is shown in  FIG. 7 . As shown in  FIG. 7 , the upper surface of enclosure  66  has a rectangular shape with a circular port opening for port  70 . Adhesive  71  has a corresponding circular opening such as opening  71  in alignment with the circular enclosure opening. Porous layer  72  has a rectangular shape that overlaps openings  71  and  70 . The rectangular shape of adhesive layer  72  serves to attach rectangular porous layer  74  to the upper rectangular surface of enclosure (body)  66  of pressure sensor  48 .  FIG. 8  is an assembled perspective view of pressure sensor  48  formed from the structures of  FIG. 7 . 
       FIG. 9  is a perspective view of pressure sensor  48  in an illustrative configuration in which port  70  has a cluster of holes  78 . Holes  78  may be perforations having sizes of less than 500 microns, less than 200 microns, less than 40 microns, less than 10 microns, or more than microns (as examples). Holes (pores) such as holes  78  of  FIG. 9  may sometimes be referred to as microperforations and may be sized to prevent dust from entering sensor  48  while permitting air to enter sensor  48  for pressure measurements. Holes  78  may be formed by laser drilling, micromachining, or other techniques.  FIG. 10  is an interior perspective view of the surface of a structure in enclosure  66  showing how holes  78  may pass through enclosure  66 . In the illustrative configuration of  FIG. 11 , portion  79  of enclosure structure  66  may be locally thinned to facilitate formation of holes  78 . 
       FIG. 12  is a cross-sectional side view of enclosure  66  in an illustrative configuration in which enclosure  66  has multiple enclosure structures such as inner portion  66 - 2  in which device  68  is mounted and outer portion  66 - 1  in which openings  78  have been formed. Enclosure  66  may, in general, be formed from one structural member, from two or more separate structures that are joined using press-fitting attachment techniques, using adhesive, using screws, using laser welding, using ultrasonic welding, or using other assembly techniques. The configuration of  FIG. 12  is merely illustrative. 
     As shown in the exploded perspective view of  FIG. 13 , pressure sensor  48  may be provided with a porous dust blocking structure by using adhesive  72  to attach porous layer  74  to device housing  12  or to other structure besides enclosure  66 . Additional adhesive may attach layer  74  to enclosure  66 , if desired. In the configuration of  FIG. 13 , adhesive layer  72  is being used to attach a compressible porous layer such as a layer of spongy fabric or an open-celled elastomeric foam to the inner surface of a support structure such as device housing  12 . Port  70  of sensor enclosure  66  on printed circuit  24  is pressed against layer  74  to compress layer  74  between enclosure  66  and housing  12 , as shown in the assembled view of  FIG. 14 . Air enters port  70  in the upper surface of enclosure  66  through pores  78  in layer  74  that are open to air around the exposed edges (side walls) of layer  74  (i.e., area of the wall of housing  12  that overlaps adhesive layer  72  and layer  74  and that is in alignment with port  70  may be devoid of openings). In this way, air pressure measurements may be made internally within device  10  without exposing port  70  to excessive dust. 
     During a drop event, during normal use of device  10 , or during other activities, stresses may be produced in printed circuit  24  that have a potential for damaging printed circuit  24  and/or components  26 . The risk of damage may be reduced by using screws (e.g., screws  42  and  44  or other screws) to securely attach printed circuit  24  to housing  12  or other support structures in device  10 . 
     A standoff such as standoff  82  of  FIG. 15  may be used in strengthening printed circuit  24  in the vicinity of a screw attachment point. As shown in  FIG. 15 , standoff  82  may have an opening such as opening  98 . Opening  98  may be unthreaded or threaded. As an example, opening  98  may be threaded and threaded shaft  94  of screw  80  may screw into threaded opening  98 . After screwing through standoff  82 , threaded shaft  94  may screw into threaded opening  9  in a support structure within device  10  such as housing  12 . Standoff  82  may be attached to printed circuit  24 , so by using screw  80  to attach standoff  82  to housing  12 , printed circuit  24  will be attached to housing  12 . 
     Standoff  82  may have a wider upper portion such as head  90  and a narrower lower portion such as shaft  92 . Head  90  and shaft  92  may be cylindrical or may have other suitable shapes. During assembly, standoff  82  may be inserted into opening  88  in printed circuit  24  by moving standoff  82  in direction  100  along longitudinal axis  102  of standoff  82  and opening  88 . 
     Standoff  82  may be formed from a solder compatible metal or a metal that is coated with nickel or other solder compatible metal. Opening  88  may be through hole in printed circuit  24  that is coated with metal  86  (e.g., opening  88  may be a plated through hole that is coated with metal  86  that is electroplated onto primed circuit  24 ). Some of metal  86  such as sidewall metal portion  86 - 2  may coat the cylindrical inner surface of opening  88  (i.e., the sidewalls of opening  88 ). Other portions of metal  86  such as ring-shaped upper surface metal portion  86 - 1  may cover some of the surface of printed circuit  24  surrounding opening  88 . 
     Solder  84  may be used to attach standoff  82  to printed circuit  24 . Surface portion  84 - 1  of solder  84  may be used to attach the lower surface of head  90  of standoff  82  to metal  86 - 1  on the surface of printed circuit  24 . Through hole portion  84 - 2  of solder  84  may be used to attach shaft  92  of standoff  82  to the metal portion coating the inner walls of opening  88  (i.e., metal  86 - 2 ). By employing both solder on the surface of printed circuit  24  and solder within the through hole  88  in printed circuit  24 , standoff  82  may be securely fastened to printed circuit  24 . This allows printed circuit  24  and components  26  on printed circuit  24  such as sensors  38  and  48  to be securely mounted to housing  12 . 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20150716
Publication Date: 20180515
Grant Date: 20180515
Priority Date: 20140903
Inventors: MALEK, SHAYAN
PAKULA, DAVID A.
STEPHENS, GREGORY N.
COHEN, SAWYER I.
MYERS, SCOTT A.
CATER, TYLER B.
BATES, ERIC W.
Assignee: APPLE INC
CPC Classifications: [{"code": "H05K2201/10151", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/10219", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1658", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/10598", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/181", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y02P70/611", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y02P70/50", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/10219", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/10151", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y02P70/50", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/10598", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/181", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1658", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/10598", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/10219", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/181", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K2201/10151", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1658", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 55404266