PATENT DOCUMENT

Publication Number: US-11442503-B2
Application Number: US-201816609176-A
Country: US
Kind Code: B2

Title: Wearable bands with embedded circuitry

Abstract:
An electronic device such as a wearable electronic device may have a band. The band may form a stand-alone device or a strap for a wristwatch unit or other device. Electrical components may be mounted on flexible printed circuit substrates. A substrate may be encapsulated by elastomeric polymer material or other material forming the band. The elastomeric polymer material may form cavities that receive the electrical components. Components such as light-emitting diodes may be mounted to the flexible printed circuit substrates so that the light-emitting diodes are located in the cavities. Reflective sidewalls in the cavities may reflect light from the light-emitting diodes outwardly through a thinned portion of the band. Light-diffusing material in the cavities may be formed from clear polymer with light-scattering particles.

Claims:
What is claimed is: 
     
       1. A wearable electronic device, comprising:
 a band having portions forming cavities; 
 a flexible printed circuit having serpentine portions; and 
 electrical components on the flexible printed circuit that are located in the cavities, wherein the electrical components comprise pixels that form a display, wherein the band has a portion configured to pass light emitted from the electrical components, and wherein the portion is visibly opaque when the electrical components are not emitting light. 
 
     
     
       2. The wearable electronic device defined in  claim 1  further comprising encapsulant in the cavities that covers the electrical components. 
     
     
       3. The wearable electronic device defined in  claim 2  wherein the encapsulant comprises clear polymer with light-scattering particles. 
     
     
       4. The wearable electronic device defined in  claim 1  wherein the band comprises elastomeric polymer. 
     
     
       5. The wearable electronic device defined in  claim 1  wherein the electrical components further comprise light-emitting diodes. 
     
     
       6. The wearable electronic device defined in  claim 5  wherein the cavities have reflective walls. 
     
     
       7. The wearable electronic device defined in  claim 1  wherein the electrical components further comprise a light-emitting device and a light detector. 
     
     
       8. The wearable electronic device defined in  claim 1  wherein the electrical components further comprise electrocardiogram electrodes and wherein the wearable electronic device further comprises control circuitry configured to measure an electrocardiogram using signals from the electrocardiogram electrodes. 
     
     
       9. The wearable electronic device defined in  claim 1  wherein the electrical components further comprise components configured to measure moisture. 
     
     
       10. The wearable electronic device defined in  claim 1  wherein the electrical components further comprise a component selected from the group consisting of: a gas sensor, a humidity sensor, an air particulate sensor, a temperature sensor, a photovoltaic device, a piezoelectric energy harvesting device, a wireless power receiving circuit, a wireless communications circuit, and a haptic output device. 
     
     
       11. The wearable electronic device defined in  claim 1  wherein the electrical components further comprise an ultraviolet light sensor. 
     
     
       12. The wearable electronic device defined in  claim 11  wherein the electrical components further include light-emitting diodes and wherein the wearable electronic device comprises control circuitry configured to control the light-emitting diodes based on information from the ultraviolet light sensor. 
     
     
       13. A watch band configured to be coupled to a main unit of a watch, the watch band comprising:
 an elastomeric band, wherein the elastomeric band has a first portion and a second portion; 
 a flexible printed circuit having serpentine portions embedded in the elastomeric band, wherein the flexible printed circuit has first electrical contacts configured to mate with second electrical contacts in the main unit of the watch; 
 sensors mounted on the flexible printed circuit and configured to generate data; 
 a clasp that couples the first portion of the elastomeric band to the second portion of the elastomeric band, wherein the clasp comprises interconnects that are coupled to the flexible printed circuit and carry the data; and 
 light-emitting diodes on the flexible printed circuit that are configured to emit light through at least some of the elastomeric band material. 
 
     
     
       14. The watch band defined in  claim 13  wherein the elastomeric band has opposing first and second surfaces, wherein the light-emitting diodes emit light through the first surface, and wherein the sensors gather sensor readings through the second surface. 
     
     
       15. An electronic device, comprising:
 a strap having first and second surfaces, wherein the first surface faces a first direction and the second surface faces a second direction that is opposite the first direction; 
 an electrical unit coupled to the strap; 
 light-emitting diodes that emit light through the first surface in a given direction, wherein the strap comprises elastomeric polymer, wherein the light-emitting diodes are each formed in respective cavities in the elastomeric polymer, and wherein the cavities have reflective sidewalls that extend between the first and second surfaces in the given direction; 
 sensors that make sensor measurements through the second surface; and 
 a flexible printed circuit substrate coupled to the light-emitting diodes. 
 
     
     
       16. The electronic device defined in  claim 15  wherein the flexible printed circuit substrate includes at least one serpentine segment, the electronic device further comprising clear polymer with light-diffusing particles in the cavities.

Description:
This application claims priority to provisional patent application No. 62/507,635, filed on May 17, 2017, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This relates generally to electronic devices and, more particularly, to wearable devices. 
     Electronic devices may include input-output components such as sensors and light-emitting components. It can be challenging to incorporate components such as these into a wearable device. If care is not taken, the wearable device will be overly fragile, bulky, or unattractive. 
     SUMMARY 
     An electronic device such as a wearable electronic device may have a band. The band may form a stand-alone device or a strap for a wristwatch or other device. The band may have electrical components. The electrical components may be mounted on flexible printed circuits. A flexible printed circuit may be encapsulated by elastomeric polymer material or other material forming the band. Portions of the flexible printed circuit may have serpentine shapes to enhance flexibility and avoid metal trace cracking. 
     The elastomeric polymer material may form cavities that receive the electrical components. Electrical components such as light-emitting diodes may be mounted to the flexible printed circuit substrates so that the light-emitting diodes are located in the cavities. Reflective sidewalls in the cavities may reflect light from the light-emitting diodes outwardly through a thinned portion of the band. Light-diffusing material in the cavities may be formed from clear polymer with light-scattering particles. 
     Electrical components in the band may include buttons, touch sensors, and other input devices, may include sensors such as light sensors, temperature sensors, force sensors, humidity sensors, moisture sensors, particulate sensors, magnetic sensors, accelerometers, pressure sensors, physiological sensors, heart beat sensors, electrocardiogram electrodes for sensing electrocardiograms, ultraviolet light sensors, and other sensors. In some configurations, some electrical components such as sensors may face downwardly towards a user&#39;s wrist skin or other portion of a user&#39;s body and other electrical components such as light-emitting diodes may face outwardly towards a user&#39;s eyes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of an illustrative electronic device in accordance with an embodiment. 
         FIG. 2  is a perspective view of an illustrative wearable electronic device such as a wristwatch with a strap in accordance with an embodiment. 
         FIG. 3  is a side view of an illustrative wearable electronic device in accordance with an embodiment. 
         FIG. 4  is a cross-sectional side view of light-emitting diodes in an illustrative package without sidewalls in accordance with an embodiment. 
         FIG. 5  is a cross-sectional side view of light-emitting diodes in an illustrative package with vertical sidewalls in accordance with an embodiment. 
         FIG. 6  is a cross-sectional side view of light-emitting diodes in an illustrative package with tapered sidewalls in accordance with an embodiment. 
         FIG. 7  is a cross-sectional side view of an illustrative light-emitting diode such as a packaged light-emitting diode device in a cavity in a wearable device structure such as a band in accordance with an embodiment. 
         FIG. 8  is a cross-sectional side view of an illustrative band having an array of cavities with respective components such as light-emitting diode devices in accordance with an embodiment. 
         FIGS. 9 and 10  are cross-sectional side views of an illustrative band at different stages of fabrication in accordance with an embodiment. 
         FIG. 11  is a cross-sectional side view of an illustrative partially assembled structure for incorporation into a band in accordance with an embodiment. 
         FIG. 12  is a cross-sectional side view of an illustrative band having a flexible printed circuit substrate with components mounted on opposing upper and lower surfaces in accordance with an embodiment. 
         FIG. 13  is a cross-sectional side view of an illustrative band having first and second flexible printed circuits having respective first and second sets of components mounted to face away from each other outwardly through the band in accordance with an embodiment. 
         FIG. 14  is a top view of an illustrative flexible printed circuit with a meandering shape and meandering signal traces in accordance with an embodiment. 
         FIG. 15  is a diagram showing how the flexible printed circuit of  FIG. 14  may be provided with connector contacts that allow the flexible printed circuit to couple to mating contacts in a connector on a watch unit or other electrical device structure in accordance with an embodiment. 
         FIG. 16  is a top view of an illustrative flexible printed circuit with a grid-shaped flexible printed circuit having rows and columns of components in an array that are interconnected by meandering segments of the flexible printed circuit in accordance with an embodiment. 
         FIG. 17  is a top view of an illustrative band and main unit in an electronic device showing how a buckle may be coupled to a band in accordance with an embodiment. 
         FIG. 18  is a cross-sectional side view of a portion of a device showing how a buckle in the device may have upper and lower mating portions in accordance with an embodiment. 
         FIG. 19  is a top view of a portion of a band with a display and an electrocardiogram electrode in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An illustrative electronic device such as a wearable 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 wearable band such as a strap for a wristwatch device (detached from or coupled to a main wristwatch unit), a wearable band without any wristwatch unit (e.g., a band of the type sometimes referred to as a health band, fitness band, or activity band), an earring, a key-chain 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 display, a computer display that contains an embedded computer, a computer display that does not contain an embedded computer, a gaming device, a navigation device, a remote control, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, 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, power management units, audio chips, application specific integrated circuits, etc. 
     Input-output circuitry in device  10  such as input-output devices  12  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  12  may include light-emitting components. For example, input-output devices can include devices such as a display and/or other light sources  14 . Light sources  14  may include one or more individual light-emitting devices such as light-emitting diode(s), laser(s), and/or lamp(s). Light sources  12  may also include arrays of pixels for forming displays such as liquid crystal displays, organic light-emitting diode displays, displays formed from crystalline semiconductor dies (microLEDs), etc. 
     Input-output devices  12  may include input component such as buttons, touch sensors (e.g., capacitive touch sensors, optical touch sensors, etc.), force sensors, and/or other devices for receiving input such as button press input and/or touch or force sensor input. 
     Sensors  20  may be used in gathering environmental measurements and/or user input and may include ambient light sensors (visible light sensors, color sensitive light sensors, ultraviolet light sensors, etc.), optical proximity sensors, capacitive proximity sensors, temperature sensors, force sensors (e.g., for measuring biometric information), gas pressure sensors, heart rate sensors, blood oxygen level sensors (e.g., based on emitted and detected light), electrocardiogram sensors (e.g., sensors for measuring electrical signals on a user&#39;s body), particulate sensors (e.g., sensors that use light measurements and/or other measurements to measure particulate concentration in the air), image sensors (cameras), gas pressure sensors, carbon dioxide sensors and/or sensors measuring other gas concentrations, position and/or orientation sensors (e.g., inertial measurement units based on one or more sensors such as accelerometers, gyroscopes, and/or compasses), accelerometers for gathering user tap input, etc. 
     Haptic output devices  22  may include piezoelectric devices, electromagnetic actuators, and/or other actuators for generating haptic output. 
     Device  10  may include one or more batteries such as battery  24 . Battery  24  may be recharged via a wired connection or, if desired, device  10  may recharge battery  24  using wirelessly received power. Power may be received wirelessly using wireless power receiving circuitry  36 . Wireless power receiving circuitry  36  may include, for example, inductive charging components such as coil  38  and a corresponding rectifier circuit or other wireless power receiving circuit for converting wirelessly received power from coil  38  into direct-current power for powering device  10  and charging battery  24 . If desired, ambient light can be converted into direct-current power for device  10  using photovoltaic device  26  (solar cells). Energy can also be harvested from movements of the user of device  10  (e.g., using piezoelectric energy harvesting device  28  or other energy harvesting circuitry). 
     Control circuitry  16  may use communications circuitry  30  to transmit data to external equipment and to receive data from external equipment. Communications circuitry  30  may include wireless communication circuitry such as one or more antennas such as antenna  32  and associate radio-frequency transceiver circuitry  34 . Transceiver circuitry  34  may include wireless local area network transceiver circuitry (e.g., WiFi® circuitry), Bluetooth® circuitry, cellular telephone transceiver circuitry, millimeter wave transceiver circuitry, near-field communications circuitry, and/or wireless circuitry that transmits and/or receives signals using light (e.g., with light-emitting diodes, lasers, or other light sources and corresponding light detectors such as photodetectors). 
       FIG. 2  is a perspective view of an illustrative electronic device  10 . Device  10  of  FIG. 2  is a wristwatch and may include components such as main electrical unit  52  and/or band  42 . Band  42  may also be configured to operate as a stand-alone unit. Illustrative configurations for device  10  in which device  10  includes band  42  (e.g., a removable strap for main unit  52 , a stand-alone band without an associated main unit  52 , a band portion of a complete wristwatch, etc.) may sometimes be described herein as examples. In general, device  10  may include any suitable structures (e.g., different types of wearable housings, etc.) that incorporate circuitry of the type shown in  FIG. 1 . The circuitry of  FIG. 1  may be located entirely in band  42  and/or may be located partially in main unit  52  and partially in band  42 . 
     As shown in  FIG. 2 , main unit  52  may include a display such as touch screen display  50  and input-output devices such as rotatable button  40 . Band (strap)  42  may be coupled to main unit  52  using magnets, pins, a tongue-and-groove configuration, using housing slits or other openings that receive band  42 , and/or other configurations in which band  42  is attached to main unit  52 . 
     Band  42  may be a single unitary band (e.g., a loop or a C-shaped band having ends that attach to respective edges of main unit  52 ) or may be formed from first and second portions that can be joined by clasp  44  (e.g., a magnetic clasp, a mechanical clasp, etc.). Band  42  may be formed from elastomeric polymer (e.g., silicone and/or other stretchable plastics), may be formed from metal (e.g., metal links, interlinked chain links, etc.), may be formed from fabric (e.g., fabric such as knit fabric, woven fabric, and/or braided fabric), may be formed from other materials (e.g., wood or other natural materials, ceramic, crystalline materials, etc.), and/or may be formed from a combination of these materials. Configurations in which band  42  is formed from elastomeric polymer materials may sometimes be described herein as an example. This is, however, merely illustrative. Band  42  may, in general, be formed from any suitable materials. 
     Portions of band  42  may be provided with input-output devices  12  and/or other components such as the illustrative circuitry of device  10  of  FIG. 1 . The circuitry of device  10  may, for example, be formed on the outer surface of band  42  and/or on the inner surface of band  42 . As an example, light sources  14  (e.g., a pixel array, one or more light-emitting diodes, etc.) may be formed in a region such as region  46  of band  42  of  FIG. 2 . Region  46  may be circular, oval, rectangular, and/or may have other shapes. Region  46  may be a single contiguous area on band  42  and/or may include multiple discrete areas. Region  46  of  FIG. 2  is located on the outer surface of band  42 , but regions such as region  46  may, if desired, extend onto the inner surface of band  42  (e.g., the surface of band  42  that faces a user&#39;s skin such as a user&#39;s wrist skin when device  10  is worn on the wrist of a user). Region  46  may include input devices (e.g., touch sensors, buttons, force sensors, cameras, etc.) and may include output devices (e.g., haptic device  22  and light sources  14 ). For example, region  46  may include light-emitting devices such as light-emitting diodes  48 . 
     Light-emitting diodes  48  may be arranged in a circular pattern, a rectangular pattern (e.g., a rectangular array having rows and columns), may be arranged in a pattern with a coarse pitch (e.g., a pixel-to-pixel spacing of 0.1-1 mm, greater than 0.5 mm, less than 2 mm, etc.) to serve as a status indicator or a display with a relatively low resolution and/or may be arranged in a pattern with a fine pitch (e.g., a pixel-to-pixel spacing of 0.01 mm, less than 0.01 mm, 0.01-0.1 mm, more than 0.05 mm, etc.) to serve as a display that displays images. Light-emitting diodes  48  may include bare unpackaged crystalline semiconductor dies and/or may include packaged light-emitting diodes. Light-emitting diodes  48  may operate at infrared, ultraviolet, and/or visible light wavelengths. For example, light-emitting diodes  48  may supply visible light such as red, green, and blue light. 
     During operation, the light-emitting diodes  48  of region  46  may be used to provide a user of device  10  with visual output such as alerts (e.g., timer alerts, incoming message alerts, etc.), emojis, messages, text, graphics, images, moving images, flashing lights or lights of particular colors or patterns of colors that serve as status indicators (e.g., power level indicators, wireless signal strength indicators, hear beats per minute readouts, an ultraviolet light exposure indicator, etc.), and/or other suitable visual output. 
       FIG. 3  shows how band  42  may be operated separately from main unit  52  (e.g., to serve as a stand-along fitness band, etc.). If desired, portion  54  of band  42  may be provided with magnets or other components to facilitate removable attachment of main unit  52 . Band  42  of  FIG. 3  may be claspless (as shown in  FIG. 3 ) or may be provided with a clasp such as clasp  44  of  FIG. 2 . 
       FIG. 4  is a cross-sectional side view of an illustrative packaged light-emitting diode device. Packaged light-emitting diode device  56  may include one or more light-emitting diodes and/or laser diodes on one or more semiconductor dies. As an example, each packaged light-emitting diode device  56  may include one or more light-emitting diodes  60 . Diodes  60  may be formed on a common die or separate respective dies. Light-emitting diodes  60  may have the same color or may have different colors. Device  56  may include one light-emitting diode  60 , at least two light-emitting diodes  60 , at least three light-emitting diodes  60 , at least four light-emitting diodes  60 , or other suitable number of light-emitting diodes  60 . 
     In the illustrative configuration of  FIG. 4 , device  56  includes three light-emitting diodes  60 . These three light-emitting diodes  60  may include, for example, a red light-emitting diode, a green light-emitting diode, and a blue light-emitting diode. If desired, diodes  60  of other colors may be used (e.g., white light-emitting diodes, yellow light-emitting diodes, etc.). 
     Packaged light-emitting diode device  56  may include package encapsulant  62 . Encapsulant  62  may be formed from an insulating material such as clear polymer. If desired, light-diffusing particles  64  may be incorporated into some or all of encapsulant  62 . Light-diffusing particles  64  may be formed from inorganic particles with a high index of refraction (e.g., titanium oxide, aluminum oxide, etc.), and/or other light-scattering structures. 
     One or more edges of each device  56  may have sidewalls such as illustrative sidewalls  66  of  FIG. 5 . Sidewalls  66  may be formed from white polymer to help reflect light that has been emitted by light-emitting diodes or may be formed from other suitable material (e.g., opaque material to prevent light leakage between adjacent devices  56 , polymers such as black polymers, polymers such as epoxy doped with light scattering particles or other polymers containing light scattering particles such as titanium dioxide particles or other particles with indices of refraction that differ from the indices of refraction of the polymers, etc.). 
     If desired, the inner surfaces of sidewalls  66  may be coated with a reflective coating such as coating  66 ′. Coating  66 ′ may be a layer of white polymer, a dielectric stack that is configured to form a mirror coating, a metal coating, and/or other reflective coating material. Sidewalls  66  may be formed on all four edges of device  56 , may be formed on two of the four edges of device (e.g., a pair of opposing edges), etc. As shown in  FIG. 6 , sidewalls  66  may be tapered. The slanted shape of tapered sidewalls  66  of  FIG. 6  may help direct emitted light upwards in direction Z. 
     Electrical components such as devices  56  may be mounted on one or more substrates in band  42 . For example, devices  56  and other electrical components may be mounted on one or more flexible printed circuits such as flexible printed circuit  78  of  FIG. 7 . Flexible printed circuit  78  may be formed from metal traces on a sheet of polyimide or other flexible polymer layer. 
     Flexible printed circuits such as flexible printed circuit  78  may be covered with band material such as polymer  74  or other material. Polymer  74  may be, for example, elastomeric polymer that allows band  42  to stretch. As shown in  FIG. 7 , polymer  74  may be patterned by injection molding or other techniques to cover flexible printed circuit  78  while forming cavities such as cavity  70 . One or more devices  56  and/or other electrical components may be mounted to flexible printed circuit  78  within each cavity  70 . 
     Cavity  70  may have vertical sidewalls and/or tapered sidewalls of the type shown in  FIG. 7  that are formed from material  74 . Material  74  may be reflective (e.g., material  74  may be formed from white polymer, etc.) and/or the surfaces of material  74  that line cavity  70  may be provided with a reflective coating such as coating  74 ′. Coating  74 ′ may be formed from white polymer, a dielectric mirror coating formed from a stack of dielectric materials of different indices of refraction, and/or metal. 
     The interior of cavity  70  may be filled with polymer  72  (e.g., clear polymer). Polymer  72  may include light-scattering particles such as particles  64  (e.g., polymer  72  and particles  64  may form a light diffusing material in cavity  70  that helps to diffuse emitted light from device  56 ). If desired, a portion of polymer  72  may be free of particles  64  (e.g., the portion of polymer  72  above line  76  may include light-scattering particles  64  and the portion of polymer  72  below line  76  may be clear and free of light-scattering particles). If desired, cavity  70  can be filled with materials that enhance light extraction. The materials may have higher or lower refractive index values than encapsulation  62  and/or may include a stack of materials with gradient refractive indices. The materials may contain particles (e.g., inorganic particles such as metal oxide particles, etc.) with various refractive indices. One or more layers of material may have patterned portions to produce desired optical effects. For example, one or more layers may be formed in the shapes of lenses, may have roughened surfaces to help diffuse emitted light, etc. 
       FIG. 8  is a cross-sectional side view of band  42  in an illustrative configuration in which cavities  70  filled with polymer  72  have been formed in band structures of polymer  74 . Polymer  74  may include portions above flexible printed circuit  78  and below flexible printed circuit  78  (e.g., polymer  74  may surround flexible printed circuit  78 ) to form band  42 . Portion  74 T of polymer  74  overlaps each cavity  70  and may have a thickness T (e.g., 200-300 microns, at least 50 microns, less than 500 microns, etc.) that is sufficiently thin to allow light from light-emitting components such as packaged light-emitting diode devices  56  to pass through portion  74 T. When devices  56  are turned off and are not emitting light, portion  74 T may have an opaque appearance that hides internal components such as devices  56  from view. When devices  56  are turned on and are emitting light, the light may be visible to a viewer such as viewer  80  who is viewing band  42  in direction  82 . If desired, light-based components such as light-emitting diodes, light detectors, etc. may be located under clear windows in an opaque portion of band  42  (see, e.g., optional window  71 ). 
     Band  42  may be fabricated using molding operations, laminating operations, and/or band  42  may be formed using other processes for patterning polymer  74  and/or other materials.  FIGS. 9 and 10  are cross-sectional side views of band  42  during an illustrative fabrication process. As shown in  FIG. 9 , polymer portion  74 - 1  may be formed by molding a first shot of polymer material in a mold. Polymer portion  74 - 1  may have the shape of a thin sheet. Flexible printed circuit  78  and devices  56  may be attached to polymer portion  74 - 1  during molding (e.g., by including these structures in the mold cavity) or after molding (e.g., by laminating with adhesive, etc.). 
     After forming the structures of  FIG. 9 , a second shot of polymer may be molded over flexible printed circuit  78  to form polymer portion  74 - 2  of  FIG. 10 . Cavities  70  may be filled with polymer encapsulant  72  (e.g., with embedded light-scattering particles  64 ) using an ink-jet printing tool or other polymer patterning equipment. A third shot of polymer (polymer portion  74 - 3 ) may be molded over polymer portions  74 - 2  and  74 - 1 , and flexible printed circuit  78  to form band  42 . Polymer portion  74 - 3  may be opaque with a sufficient thickness to permit light from devices  56  to pass through layer  74 - 3  (e.g. polymer portions  74 - 1 ,  74 - 2 , and  74 - 3  may be formed from polymer of the same color such as black polymer, white polymer, red polymer, etc.) or, if desired, different shots of plastic used in forming band  42  may have different colors and/or may be translucent, clear, etc. If desired, four or more different shots of plastic or fewer than three shots may be used in forming band  42 . Clear windows, perforations, and/or other structures may be formed in polymer  74  to enhance light transmission, to form air passageways, etc. 
       FIG. 11  shows how plastic portion  74 - 2  may be molded over printed circuit  78  to form cavities  70  in alignment with devices  56  and shows how cavities  70  may be filled with polymer  72  (e.g., polymer with embedded light-scattering particles  64  so that polymer  72  forms a light-diffusing layer). This type of structure may subsequently be embedded in one or more additional shots of polymer to form band  42 . Configurations in which band  42  is formed using other molding processes, in which band  42  is formed by cutting premolded polymer, and/or in which band  42  is formed using other techniques (lamination, laser processing, etc.) may also be used. The illustrative fabrication operations of  FIGS. 9, 10, and 11  are merely illustrative. 
       FIG. 12  shows how electrical components  84  may be mounted on opposing upper and lower sides of flexible printed circuit  78 . Polymer  74  may be molded around components  84  to form band  42 . If desired, polymer  74  may be patterned to form cavities  70  filled with polymer  72  (see, e.g.,  FIG. 8 ). In the example of  FIG. 13 , band  42  contains two flexible printed circuits  78 . An upper of the two flexible printed circuits  78  has an upper set of electrical components  84  that face upwards. A lower of the two flexible printed circuits  78  has a lower set of electrical components  84  that face downwards, away from the upper flexible printed circuit and away from the components mounted on the upper flexible printed circuit. If desired, cavities  70  filled with polymer  72  may be formed in polymer  74  of  FIG. 13  in alignment with components  84 , as described in connection with  FIG. 8 . 
     Electrical components  84  may include light-emitting diode devices  56  and/or other electrical components (e.g., components that form some or all of devices such as display and other light sources  14 ), buttons, touch sensors, and other input devices  18 , sensors  20  (e.g., light sensors, touch sensors, force sensors, accelerometers for gathering user tap input and/or orientation and motion information, and/or other sensors in device  10 ), haptic devices  22 , battery  24 , photovoltaic device  26 , piezoelectric energy harvesting device  28 , communications circuitry  30 , wireless power receiving circuitry  36 , and/or control circuitry  16 . Electrical components  84  such as these may face outwardly on both the upper and lower surfaces of band  42  (see, e.g.,  FIGS. 12 and 13 ) or may face upwardly (see, e.g., illustrative electrical components  84  such as devices  56  of  FIG. 8 ). 
     As the examples of  FIGS. 8, 12, and 13  demonstrate, one or more flexible printed circuits  78  may be populated with electrical components  84  and these electrical components may face upwards and/or downwards relative to band  42  and the user&#39;s skin (e.g., the user&#39;s wrist, which may lie under the lower surface of band  42 ). Using configurations such as these, electrical components  84  of band  42  may gather information on a user&#39;s health, may gather information on the environment, and/or may gather user input (e.g., taps or other touch gestures, etc.). 
     Consider, as an example, the measurement of a user&#39;s blood oxygen level. Using components  84  that emit light (e.g., packaged light-emitting diodes  56 ), light may be emitted towards a user&#39;s finger in contact with the upper surface of band  42 . This light may pass through a user&#39;s blood, which may absorb the light in proportion to the amount of oxygen being carried by the user&#39;s blood. Using a photodetector in diodes  56 , the light may be measured and the amount of absorbed light determined to produce a blood oxygen reading (e.g., components  84  may form a pulse oximetry device for band  42 ). 
     As another example, components  84  on the upper surface of band  42  may be light-emitting components to provide a user with visual output. Components  84  on the lower surface of band  42  may include pressure sensors (force sensors, strain gauges, etc.) that sense arterial pressure (e.g., the pressure of a user&#39;s arteries in the skin of a user&#39;s wrist that is in contact with the lower surface of band  42 ). 
     If desired, components  84  may form physiological sensors for measuring a user&#39;s perspiration level, temperature, or other physiological parameters. For example, the components  84  facing downwards from band  42  may include moisture sensors and/or electrical conductivity measurement electrodes. These components may be configured to measure moisture levels (e.g., a user&#39;s perspiration level) and thereby determine whether a user is properly hydrated, etc. Temperature measurements on a user&#39;s skin (e.g., a user&#39;s body temperature) may be performed with temperature sensors in the components  84  facing the user&#39;s skin and/or temperature measurements may be made using outwardly facing temperature sensors (e.g., ambient temperature measurements). 
     A user&#39;s heart rate may be measured by pressure sensors, using optical detection techniques, and/or using other measurements. As an example, one of components  84  (e.g., an infrared light-emitting diode) may emit infrared light downwards through the lower surface of band  42  and an adjacent component  84  (e.g., a photodetector) may measure corresponding reflected light. By analyzing the detected reflected light signals, the user&#39;s heartbeat can be determined. 
     Electrocardiograms may be measured by directing a user to place a fingertip of one hand onto a first electrode (e.g., an electrode formed from one of components  84  that passes through the upper surface of band  42  as illustrated by component  84 ′ of  FIG. 13  to expose the electrode) while band  42  is being worn on the user&#39;s other hand. A second electrode (see, e.g., component  84 ″, which passes through the lower surface of band  42  of  FIG. 13 ) may be in contact with the user&#39;s wrist skin. Control circuitry  16  can be configured to measure the user&#39;s electrocardiogram using signals from the first and second electrodes. 
     In another illustrative configuration, one of components  84  (e.g., an upwardly facing component) may be an ultraviolet light sensor. Control circuitry  16  may gather ultraviolet light measurements as a function of time using the ultraviolet light sensor. The amount of cumulative ultraviolet light exposure for the user may be indicated visually using an ultraviolet light exposure indicator formed from light-emitting diodes  48  of  FIG. 1  (e.g., pixels formed by packaged devices  56 , pixels in a display, etc.). Components  84  may include gas sensors to measure gas concentrations, humidity sensors to measure air humidity levels, particulate sensors to measure particulate concentrations in the air, and/or other sensors to monitor the ambient environment. 
     In some configurations, components  84  may be configured to gather user input (e.g., taps, swipes, and/or other gesture input). For example, components  84  may include dome switches and/or other switches that respond to applied pressure from a user&#39;s fingertips. As another example, components  84  may include light sources and light detectors that can be used to measure proximity (e.g., whether a user&#39;s fingers or other body parts are adjacent to band  42 ). User finger force input can be gathered using strain gauges, piezoelectric force sensors, and/or other force sensors. If desired, an accelerometer in components  84  may monitor for user finger taps on band  42 . If accelerometer measurements indicate that the user&#39;s fingers have tapped against band  42  with a desired pattern (e.g., a double tap, single tap, triple tap, etc.), a user&#39;s input can be confirmed (e.g., to make a menu selection, to answer a phone call, to adjust media playback settings, to turn on or off a component of band  42 , to power band  42  on or off, and/or to adjust the operation of other portions of an electronic device such as device  10 , etc.). When a user finger press or other touch or force input is detected, control circuitry  16  can direct a haptic output component in components  84  to supply a user&#39;s finger with a corresponding haptic output pulse (e.g., haptic output that serves as feedback indicating that a touch sensor input or other input has been detected by band  42 ). 
     To enhance flexibility for band  42  and avoid circuit damage and possible delamination of components  84  from printed circuit  78 , it may be desirable to provide portions of printed circuit  78  with serpentine shapes. As an example, printed circuit  78  may have portions with serpentine footprints, as shown in  FIG. 14 . In the arrangement of  FIG. 14 , portion  78 R of printed circuit  78  has a rectangular shape and may have contacts for coupling signal lines in printed circuit  78  to a connector in main unit  52  of device  10 . Portion  78 L of printed circuit  78  may have a meandering path shape. 
     Printed circuit  78  may include one or more layers of patterned metal traces such as metal trace  88  (e.g. copper traces, etc.) that form signal lines in printed circuit  78 . The use of meandering shapes (e.g., serpentine shapes) for printed circuit  78  and metal traces  88  may help minimize stress and thereby help prevent stress-induced cracks from forming in printed circuit  78 . Portion  78 C of printed circuit  78  of  FIG. 14  has a circular shape formed from radially extending serpentine path segments. Components  84  (e.g., packaged light-emitting diodes  56 ) may be arranged in a radially symmetric pattern forming concentric circles of components  84  (e.g., to form a circular status indicator with light-emitting diodes such as light-emitting diodes  48  of circular region  46  in  FIG. 1 ). Other shapes and layouts may be used for printed circuit  78  and the components on printed circuit  78 , if desired. 
       FIG. 15  shows how portion  78 D of flexible printed circuit  78  in band  42  may have contacts  92  that mate with corresponding contacts  90  in main unit  52  of device  10 . This allows unit  52  and band  42  to exchange power signals and/or data signals. For example, control circuitry in unit  52  may be used to send control signals to a controller integrated circuit or other integrated circuit(s) on portion  78 D such as circuit  94  (e.g., control circuitry  16 ) that circuit  94  uses to control components  84  (e.g., packaged light-emitting diodes  56 ). If desired, control circuitry in unit  52  may directly send control signals to components  84 . The signal paths in printed circuit  78  may also be used in routing sensor measurements, user input, and other signals from printed circuit  78  to main unit  52  and/or to processing circuitry in circuits such as circuit  94 . 
     If desired, components  84  may be mounted on a flexible printed circuit with serpentine portions in rectangular arrays and/or other patterns other than the illustrative patterns of  FIG. 14 . As shown in  FIG. 16 , for example, components  84  may be arranged in an array having rows and columns of components  84  interconnected by serpentine segments of printed circuit  78 . Printed circuit  78  may, for example, have a grid shape with an array of openings  91 . 
     As shown in  FIG. 17 , device  10  may have a watchband buckle (clasp) such as buckle  100 . Control circuitry  16  may include a system-on-chip device. Additional circuitry may also be located in block  16  of  FIG. 17  (e.g., a microphone, a power management integrated circuit, battery  24 , etc.). Antenna  32  and other components (e.g., sensors  20 , haptic devices  22 , etc.) may be formed on a flexible printed circuit in band  42  or may be formed from other structures in band  42 . Communications paths  103  may handle I 2 C communications, Serial Peripheral Interface (SPI) communications, other data, and/or power signals. 
       FIG. 18  is a cross-sectional side view of device  10  showing how buckle  100  may have upper and lower (top and bottom) portions coupled with clips  102 . Clips  102  may be attached to each other using magnets and/or mechanical engagement structures. Clips  102  may also include interconnects (e.g., metal contacts) for carrying power and/or data. If desired, optical communications circuitry may be include in clips  102  or other portion of buckle  100  (e.g., a light-emitting diode or laser source and a corresponding photodetector such as a photodiode in each half of buckle  100 ). Wireless charging coils  38  may be formed in one or both buckle portions and/or in one or both of portions of band  42 . Display  14  may be formed from pixels on a flexible substrate encased in diffusive band material. Band  42  may be formed from fabric, laminated layers, leather, polymer, opaque materials such as polymer, translucent materials such as polymer, and/or other materials. Sensors  20  in band  42  may include pulse-oximeters, heart rate sensors, and other biological sensors, light sensors such as ultraviolet light sensors, ambient light sensors, and other sensors  20 . Haptic elements  22  may be placed in band  42  adjacent to sensors  20  or elsewhere in band  42 . Buckle  100  may be formed from a dielectric (e.g., a ceramic or glass or polymer material that is radio-frequency transparent (e.g., in configurations in which antenna  32  is in buckle  100 ) and/or may be a dielectric material or other material that is compatible with reception of wireless charging signals for coil  38 . The top portion of buckle  100  may include display drive circuit  108  and speaker  106 . Audio output from speaker  106  may, if desired, be used in creating haptic output for a user&#39;s skin. 
       FIG. 19  shows how display  14  may include an array of pixels P. Pixels P may be covered with an array of indium tin oxide pads or other capacitive sensor electrodes  112  (e.g., display  14  may include an overlapping touch sensor so that display  14  functions as a touch screen display). Passive or active matrix configurations may be used for pixels P. Data and gate lines may extend between band  42  and buckle  100  (e.g., in configurations of the type shown in  FIG. 19  in which display drive circuitry  108  is in buckle  100 ). Electrodes  110  may be used for gathering biometric information such as electrocardiogram signals. Main unit  52  can be a digital watch unit that includes a touch screen and other components and/or may be a mechanical watch, a digital watch that does not include a touch screen, and/or a hybrid watch having electrical and mechanical components. In arrangements in which a mechanical watch unit is being coupled between left and right halves of band  42 , a flexible printed circuit (see, e.g., circuit  78 ), wires, optional band material  42 , and/or other electrical and/or mechanical structures may extend under the mechanical watch unit (e.g., band  42  may have a recess or other portion that is configured to receive the mechanical watch on top of band  42 ). This allows components in band  42  that are on the left and right sides of the mechanical watch to communicate with each other. 
     In some arrangements, processing and power related components may be housed in a rigid portion of device  10  (e.g., in buckle  100 ). Flexible and stretchable components such as display  14  and sensors  20  may be formed in band  42  (e.g., encapsulated in band material). Band  42  can be used as a stand-alone wristband device (e.g., without using main unit  52 ) and/or may be detachably coupled to main unit  52  or another watch component (e.g., a mechanical watch). Main unit  52  may contain a main display  14  and band  42  may, if desired contain a secondary display  14  or device  10  may only have a single display in unit  52  or band  42 . If desired, band  42 , buckle  100 , and/or main unit  52  may include solar cells to help charge battery  24 . 
     In accordance with an embodiment, a wearable electronic device is provided that includes a band having portions forming cavities, a flexible printed circuit having serpentine portions, and electrical components on the flexible printed circuit that are located in the cavities. 
     In accordance with another embodiment, the wearable electronic device includes encapsulant in the cavities that covers the electrical components. 
     In accordance with another embodiment, the encapsulant includes clear polymer with light-scattering particles. 
     In accordance with another embodiment, the band includes elastomeric polymer. 
     In accordance with another embodiment, the electrical components include light-emitting diodes. 
     In accordance with another embodiment, the cavities have reflective walls. 
     In accordance with another embodiment, the electrical components include a light-emitting device and a light detector. 
     In accordance with another embodiment, the electrical components include electrocardiogram electrodes and the wearable electronic device further includes control circuitry configured to measure an electrocardiogram using signals from the electrocardiogram electrodes. 
     In accordance with another embodiment, the electrical components include components configured to measure moisture. 
     In accordance with another embodiment, the electrical components include a component selected from the group consisting of: a gas sensor, a humidity sensor, an air particulate sensor, a temperature sensor, a photovoltaic device, a piezoelectric energy harvesting device, a wireless power receiving circuit, a wireless communications circuit, and a haptic output device. 
     In accordance with another embodiment, the electrical components include an ultraviolet light sensor. 
     In accordance with another embodiment, the electrical components include light-emitting diodes and the wearable electronic device includes control circuitry configured to control the light-emitting diodes based on information from the ultraviolet light sensor. 
     In accordance with another embodiment, the band has a portion configured to pass light emitted from the electrical components. 
     In accordance with another embodiment, the portion is visibly opaque when the electrical components are not emitting light. 
     In accordance with an embodiment, a watch band is provided that includes an elastomeric band, a flexible printed circuit having serpentine portions embedded in the elastomeric band, and light-emitting diodes on the flexible printed circuit that are configured to emit light through at least some of the elastomeric band material. 
     In accordance with another embodiment, the flexible printed circuit has contacts configured to mate with contacts on a main unit of a watch. 
     In accordance with another embodiment, the watch band includes sensors mounted on the flexible printed circuit. 
     In accordance with another embodiment, the elastomeric band has opposing first and second surfaces, the light-emitting diodes emit light through the first surface, and the sensors gather sensor readings through the second surface. 
     In accordance with another embodiment, an electronic device is provided that includes a strap having opposing first and second surfaces, an electrical unit coupled to the strap, light-emitting diodes that emit light through the first surface, the strap includes elastomeric polymer and the light-emitting diodes are formed in cavities in the elastomeric polymer that have reflective sidewalls, and sensors that make sensor measurements through the second surface and a flexible printed circuit substrate coupled to the light-emitting diodes. 
     In accordance with another embodiment, the flexible printed circuit substrate includes at least one serpentine segment, the electronic device includes clear polymer with light-diffusing particles in the cavities. 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20180517
Publication Date: 20220913
Grant Date: 20220913
Priority Date: 20170517
Inventors: HSU, YUNG-YU
GANDHI, Shubham A.
HA, Mingjing
DRZAIC, PAUL S.
HUANG, CHANG-CHIA
CHANG, HAN-CHIEH
BRADFORD, BRYCE T.
LUM, DAVID W.
BANERJEE, BHASKAR
ADJIWIBAWA, ADAM
DOYLE, DAVID A.
LUO, HONG
BROWN, MICHAEL J.
Assignee: APPLE INC
CPC Classifications: [{"code": "H05K2201/10151", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/163", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1652", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/028", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1652", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/10106", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/0166", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/163", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1652", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/10151", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/163", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K2201/10106", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/028", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/0166", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 62620948