PATENT DOCUMENT

Publication Number: US-8934228-B2
Application Number: US-201213422724-A
Country: US
Kind Code: B2

Title: Display-based speaker structures for electronic devices

Abstract:
Electronic devices that contain flexible displays and one or more display-based speaker structures may be provided. The speaker structures may be positioned under the flexible display. Portions of the flexible display may be used as speaker membranes for the speaker structures. The speaker structures may be driven by transducers that convert electrical audio signal input into sound. Piezoelectric transducers or transducers formed from coils and magnets may be used to drive the speaker structures. Speaker membranes may be formed from active display areas of the flexible display. Some, all, or substantially all of the flexible display may be used as a speaker membrane for one or more display-based speaker structures. An optional cover layer may be provided with speaker openings so that sound may pass from the display-based speaker structures to the exterior of the device.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a flexible display; 
 a speaker structure having a speaker membrane, wherein the speaker membrane is formed from a portion of the flexible display; and 
 a stiffening structure configured to stiffen the portion of the flexible display that forms the speaker membrane, wherein the stiffening structure comprises a layer of foam and first and second stiffening sheets that are attached to opposing first and second sides of the layer of foam. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the flexible display comprises an active portion configured to display images and wherein the speaker membrane is formed from the active portion of the flexible display. 
     
     
       3. The electronic device defined in  claim 1 , further comprising:
 a rigid structure; and 
 a suspension structure configured to attach portions of the speaker structure to the rigid structure. 
 
     
     
       4. The electronic device defined in  claim 3 , further comprising:
 an electronic device housing in which the flexible display is mounted, wherein the rigid structure is formed at least partly from the electronic device housing. 
 
     
     
       5. The electronic device defined in  claim 1 , further comprising:
 a cover layer formed over the flexible display, wherein the cover layer comprises at least one opening formed over the speaker membrane. 
 
     
     
       6. The electronic device defined in  claim 1  further comprising an electronic device housing in which the flexible display is mounted, wherein the electronic device housing has at least one acoustic port. 
     
     
       7. The electronic device defined in  claim 1  wherein the flexible display comprises an organic light-emitting diode display having a substrate formed from a flexible sheet of polymer. 
     
     
       8. An electronic device, comprising:
 a flexible display; and 
 a plurality of speaker structures, wherein portions of the flexible display form speaker membranes for the plurality of speaker structures, wherein the flexible display comprises:
 a set of stiffened regions, wherein each of the stiffened regions in the set of stiffened regions forms part of a respective one of the speaker structures; 
 flexible regions, wherein each of the flexible regions surrounds a respective one of the stiffened regions in the set of stiffened regions; and 
 a surrounding stiffened region, wherein each of the flexible regions is surrounded by portions of the surrounding stiffened region. 
 
 
     
     
       9. The electronic device defined in  claim 8 , further comprising:
 a plurality of stiffening structures configured to stiffen the portions of the flexible display that form the speaker membranes. 
 
     
     
       10. The electronic device defined in  claim 8  wherein the speaker structures comprise a left channel speaker and a right channel speaker. 
     
     
       11. The electronic device defined in  claim 8 , further comprising:
 transducers configured to drive the speaker structures, wherein each transducer comprises coils and a magnet. 
 
     
     
       12. The electronic device defined in  claim 8  further comprising piezoelectric transducers configured to drive the speaker structures. 
     
     
       13. The electronic device defined in  claim 8  wherein the flexible display comprises an organic light-emitting diode display having a substrate formed from a flexible sheet of polymer. 
     
     
       14. A portable electronic device, comprising:
 a housing; 
 a flexible organic light-emitting diode display mounted in the housing, wherein the flexible organic light-emitting diode display has a substrate formed from a flexible sheet of polymer; 
 at least one speaker having a transducer and a speaker membrane formed from a portion of the flexible sheet of polymer, wherein the transducer is mounted to the flexible sheet of polymer; and 
 a stiffening structure interposed between and in contact with the flexible sheet of polymer and the transducer. 
 
     
     
       15. The portable electronic device defined in  claim 14  wherein the stiffening structure comprises a composite material. 
     
     
       16. The portable electronic device defined in  claim 14  wherein the speaker membrane has a concave shape. 
     
     
       17. The portable electronic device defined in  claim 14  wherein the housing comprises a rectangular housing with four peripheral edges and wherein the flexible organic light-emitting diode display and the speaker membrane extend between the four peripheral edges. 
     
     
       18. The portable electronic device defined in  claim 14  wherein the transducer comprises coils and a magnet. 
     
     
       19. The electronic device defined in  claim 8  wherein the surrounding stiffened region completely surrounds each of the flexible regions to mechanically isolate each speaker structure from adjacent speaker structures. 
     
     
       20. The electronic device defined in  claim 1  wherein the speaker structure comprises a transducer mounted to the flexible display. 
     
     
       21. The electronic device defined in  claim 20  wherein the stiffening structure is interposed between and in contact with the transducer and the flexible display. 
     
     
       22. The electronic device defined in  claim 21  wherein the transducer comprises coils and a magnet.

Description:
This application is a continuation-in-part of patent application Ser. No. 13/171,295, filed Jun. 28, 2011, which claims the benefit of provisional patent application No. 61/454,894, filed Mar. 21, 2011, both of which are hereby incorporated by reference herein in their entireties. This application claims the benefit of and claims priority to patent application Ser. No. 13/171,295, filed Jun. 28, 2011, and to provisional patent application No. 61/454,894, filed Mar. 21, 2011. 
    
    
     BACKGROUND 
     This relates generally to electronic devices, and more particularly, to display-based speaker structures for electronic devices. 
     Electronic devices such as portable computers and cellular telephones are often provided with displays made from display structures. For example, a liquid crystal display (LCD) may be formed from a stack of display structures such as a thin-film transistor layer with display pixels for providing visual feedback to a user, a color filter layer for providing the display pixels with color, a touch screen panel for gathering touch input from a user, and a cover glass layer for protecting the display and internal components. 
     Electronic devices may also have input-output components such as speakers, buttons, microphones, and other components. There is often very little real estate available for mounting these input-output components. For example, input-output components are often mounted under an inactive portion of a display or within the sidewalls of an electronic device housing. 
     The size and number of input-output components such as speakers may be limited by the amount of space available in these locations. For example, a conventional device may have a single speaker mounted under an inactive portion of a display. The size and quality of such a speaker may be limited by a lack of space in the inactive portion of the display. Additionally, mounting a speaker in the inactive portion of a display may add undesirable width to the inactive portion of the display. 
     It would therefore be desirable to be able to provide improved arrangements for forming components such as speakers in electronic devices with displays. 
     SUMMARY 
     Electronic devices with flexible displays may be provided. The flexible displays may include one or more flexible layers. A display cover such as a cover glass layer may be mounted over a flexible display. 
     The flexible display may be an organic light-emitting diode display having a flexible substrate formed from one or more sheets of polymer. The flexible display may include a touch sensor layer having an array of capacitive touch sensor electrodes. 
     There may be one or more display-based speaker structures in the electronic device. The display-based speaker structures may be mounted under the flexible display. Portions of the flexible display may be used as speaker membranes for the display-based speaker structures. 
     The flexible display may have an active area that is configured to display images to a user. Speaker membranes may be formed from the active portion of the flexible display. The display-based speaker structures may be driven by transducers that receive an electrical audio signal input from circuitry in the electronic device. Piezoelectric transducers or transducers formed from coils and magnets may be used to drive the display-based speaker structures. 
     A stiffening structure may be used to stiffen a portion of a flexible display that is used as a speaker membrane. The stiffening structure may be formed from a layer of foam interposed between sheets of stiffening material. The stiffening structure may form a stiff and lightweight support structure that allows the speaker membrane to respond accurately to the transducer. 
     A suspension structure may be used to attach a display-based speaker structure to surrounding housing structures. The suspension structure may form a pliant interface between the speaker structure and the surrounding housing structures. The suspension structure may allow the speaker structure to vibrate during speaker operation while inhibiting lateral motion of the speaker structure. 
     Speaker structures may be configured to achieve a desired frequency response. The electronic device housing in which a speaker structure is mounted may be provided with an acoustic port to tune speaker frequency response. The type of transducer that is used in a speaker may be selected to tune speaker frequency response. The size and placement of internal device components that affect speaker volume and speaker mass may also be selected to tune speaker frequency response. 
     An electronic device may be provided with an array of display-based speaker structures. The speaker membrane for each speaker structure may be stiffened with an associated stiffening structure. Each stiffened speaker membrane may be surrounded by a ring of flexible display that is configured to absorb lateral vibrations and thus prevent interference between neighboring speakers. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of an illustrative electronic device such as a portable computer having a display and one or more speaker structures in accordance with an embodiment of the present invention. 
         FIG. 2  is a diagram of an illustrative electronic device such as a cellular telephone or other handheld device having a display and one or more speaker structures in accordance with an embodiment of the present invention. 
         FIG. 3  is a diagram of an illustrative electronic device such as a tablet computer having a display and one or more speaker structures in accordance with an embodiment of the present invention. 
         FIG. 4  is a diagram of an illustrative electronic device such as a computer monitor with a built-in computer having a display and one or more speaker structures in accordance with an embodiment of the present invention. 
         FIG. 5  is a diagram of an illustrative set of display layers that may be used to form a flexible display in accordance with an embodiment of the present invention. 
         FIG. 6  is a diagram of an illustrative set of layers that may be used to form an organic light-emitting diode display in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of a portion of an illustrative electronic device in which a flexible display forms part of a speaker structure in accordance with an embodiment of the present invention. 
         FIG. 8  is a cross-sectional side view of a portion of an illustrative electronic device in which a flexible display forms part of a speaker structure in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional side view of a portion of an illustrative electronic device in which a flexible display forms part of a speaker structure in accordance with an embodiment of the present invention. 
         FIG. 10  is a perspective view of an illustrative electronic device of the type shown in  FIG. 9  having a cover layer with speaker openings in accordance with an embodiment of the present invention. 
         FIG. 11  is a cross-sectional side view of a portion of an illustrative electronic device in which a flexible display is stiffened with a support structure in accordance with an embodiment of the present invention. 
         FIG. 12  is a cross-sectional side view of a portion of an illustrative electronic device having a curved flexible display with a curved support structure in accordance with an embodiment of the present invention. 
         FIG. 13  is a cross-sectional side view of a portion of an illustrative electronic device in which a flexible display forms part of a single speaker structure in accordance with an embodiment of the present invention. 
         FIG. 14  is a cross-sectional side view of a portion of an illustrative electronic device in which a flexible display forms part of an array of speaker structures in accordance with an embodiment of the present invention. 
         FIG. 15  is a bottom view of an illustrative electronic device of the type shown in  FIG. 14  having a flexible display that forms part of an array of speaker structures in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device may be provided with a flexible display and other user interface components. The user interface components may include buttons, switches, microphones, actuators such as solenoids, motors, and piezoelectric actuators, connector ports, touch screens, proximity sensors and other components for accepting input from, or transmitting information to, a user of the electronic device. 
     Flexible displays may be formed from flexible layers such as a flexible display layer (e.g., a flexible organic light-emitting diode array), a flexible touch-sensitive layer (e.g., a sheet of polymer with an array of transparent capacitor electrodes for a capacitive touch sensor), a flexible substrate layer, etc. These flexible layers may, if desired, be covered by a flexible or rigid cover layer (sometimes referred to as a cover glass) or may be supported by a support structure (e.g., a rigid support structure on the underside of the flexible layers). In electronic devices with flexible displays that are covered by rigid cover layers, the cover layers may be provided with openings that provide access to the flexible layers of the display in the vicinity of a user interface device. For example, a cover glass layer may have an opening that allows a button member to move relative to the cover glass layer. As another example, a cover glass layer may have one or more speaker openings through which sound may pass. 
     To maximize the area of the portion of the flexible display that is available for displaying visual information to the user, user interface components may be positioned behind, abutted against, or integrated into the flexible display. The deformable nature of the flexible display may allow a user to interact with the user interface components (input-output components) by moving the display into contact with the user interface components or by otherwise allowing the display to locally flex (e.g., to allow sound to pass through the flexible display or to allow barometric pressure measurements of the exterior environment to be made by an internal pressure sensor). 
     If desired, a portion of the flexible display may form a membrane structure for an electrical component. For example, a portion of the flexible display may form a speaker membrane for a speaker component. Components that may be provided with a membrane structure formed from a portion of a flexible display include speakers, microphones, laser microphones, pressure sensors, etc. 
     An illustrative electronic device of the type that may be provided with a flexible display is shown in  FIG. 1 . Electronic device  10  may be a computer such as a computer that is integrated into a display. For example, electronic device  10  may be a computer monitor, a laptop computer, a tablet computer, a somewhat smaller portable device such as a wrist-watch device, pendant device, or other wearable or miniature device, a cellular telephone, a media player, a tablet computer, a gaming device, a speaker device, a navigation device, a computer monitor, a television, or other electronic equipment. 
     Device  10  may include a housing such as housing  12 . Housing  12 , which may sometimes be referred to as a case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of these materials. In some situations, parts of housing  12  may be formed from dielectric or other low-conductivity material. In other situations, housing  12  or at least some of the structures that make up housing  12  may be formed from metal elements. 
     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.). 
     As shown in  FIG. 1 , housing  12  may have multiple parts. For example, housing  12  may have upper portion  12 A and lower portion  12 B. Upper portion  12 A may be coupled to lower portion  12 B using a hinge that allows portion  12 A to rotate about rotational axis  16  relative to portion  12 B. A keyboard such as keyboard  18  and a touch pad such as touch pad  20  may be mounted in housing portion  12 B. 
     Device  10  may have a flexible display such as flexible display  14 . Flexible display  14  may be formed from multiple layers of material. These layers may include a touch sensor layer such as a layer on which a pattern of indium tin oxide (ITO) electrodes or other suitable transparent electrodes have been deposited to form a capacitive touch sensor array. These layers may also include a display layer that contains an array of display pixels. The touch sensor layer and the display layer may be formed using flexible sheets of polymer (e.g., polyimide) or other substrates having thicknesses of 10 microns to 0.5 mm, having thicknesses of less than 0.2 mm, or having other suitable thicknesses (as examples). 
     The display pixel array may be an organic light-emitting diode (OLED) array, for example. Other types of flexible display pixel arrays may also be formed (e.g., electrowetting displays, electrophoretic displays, flexible liquid crystal displays, flexible electrochromic displays, etc.). The use of OLED technology to form flexible display  14  is sometimes described herein as an example. This is, however, merely illustrative. In general, any suitable type of flexible display technology may be used in forming display  14 . 
     In addition to these functional display layers (i.e., the OLED array and the optional touch sensor array), display  14  may include one or more structural layers. For example, display  14  may be covered with a flexible or rigid cover layer and/or may be mounted on a support structure (e.g., a rigid support). If desired, layers of adhesive may be used to attach flexible display layers to each other and/or to mount flexible display layers to rigid and flexible structural layers. 
     In some embodiments, display  14  may have an active area such as active area AA and an inactive area such as area IA. In active display region AA, an array of image pixels may be used to present text and images to a user of device  10 . In active region AA, display  14  may include touch sensitive components for input and interaction with a user of device  10 . If desired, both central portion AA and peripheral portion IA may be provided with display pixels (i.e., all or substantially all of the entire front planar surface of upper housing portion  12 A may be provided with display pixels). 
     In the example of  FIG. 2 , device  10  has been implemented using a housing that is sufficiently small to fit within a user&#39;s hand (e.g., device  10  of  FIG. 2  may be a handheld electronic device such as a cellular telephone). As show in  FIG. 2 , device  10  may include a display such as display  14  mounted on the front of housing  12 . Display  14  may be substantially filled with active display pixels or may have an inactive portion such as inactive portion IA that surrounds an active portion such as active portion AA. Display  14  may have openings (e.g., openings in inactive region IA or active region AA of display  14 ) such as an opening to accommodate button  22  and an opening to accommodate speaker port  24 . 
       FIG. 3  is a perspective view of electronic device  10  in a configuration in which electronic device  10  has been implemented in the form of a tablet computer. As shown in  FIG. 3 , display  14  may be mounted on the upper (front) surface of housing  12 . An opening may be formed in display  14  to accommodate button  22  (e.g., an opening may be formed in inactive region IA surrounding active region AA). 
       FIG. 4  is a perspective view of electronic device  10  in a configuration in which electronic device  10  has been implemented in the form of a television or in the form of a computer integrated into a computer monitor. As shown in  FIG. 4 , display  14  may be mounted on the front surface of housing  12 . Stand  26  may be used to support housing  12 . Display  14  may include an inactive region such as inactive region IA that surrounds active region AA. 
     An exploded perspective view of an illustrative display is shown in  FIG. 5 . As shown in  FIG. 5 , flexible display  14  may be formed by stacking multiple layers including flexible display layer  14 A and touch-sensitive layer  14 B. An optional cover layer such as cover layer  62  may be formed over flexible display  14 . Cover layer  62  may be a layer of glass, plastic, or other protective display layer. 
     Flexible display  14  may also include other layers of material such as adhesive layers, optical films, sealant layers, or other suitable layers. Flexible display layer  14 A may include image pixels formed from light-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electrowetting display elements, electrophoretic display elements, liquid crystal display (LCD) components, or other suitable image pixel structures compatible with flexible displays. 
     Touch-sensitive layer  14 B may incorporate capacitive touch electrodes such as horizontal transparent electrodes  32  and vertical transparent electrodes  34 . Touch-sensitive layer  14 B may, in general, be configured to detect the location of one or more touches or near touches on touch-sensitive layer  14 B based on capacitive, resistive, optical, acoustic, inductive, or mechanical measurements, or any phenomena that can be measured with respect to the occurrences of the one or more touches or near touches in proximity to touch sensitive layer  14 B. 
     Flexible display  14  may be formed from display pixel array layer  14 A and optional touch sensor layer  14 B. In the example of  FIG. 5 , touch-sensitive layer  14 B is interposed between cover layer  62  and flexible display layer  14 A. This arrangement is merely illustrative. If desired, flexible display layer  14 A may be interposed between cover layer  62  and touch-sensitive layer  14 B (e.g., flexible display layer  14 A may be arranged on top of touch-sensitive layer  14 B). If desired, touch-sensitive layer  14 B and flexible display layer  14 A may be integrated as a single layer. For example, capacitive touch electrodes such as electrodes  32  and  34  and display pixels such as display pixels  30  may be formed on a common substrate, if desired. 
       FIG. 6  is a cross-sectional side view of a portion of flexible display layer  14 A. As shown in  FIG. 6 , flexible display layer  14 A may contain multiple sublayers. For example, display layer  14 A may include a substrate layer such as substrate layer  15 . Substrate layer  15  may be formed from a flexible or rigid dielectric such as glass, ceramic, or plastic. As an example, substrate layer  15  may be formed from one or more flexible sheets of polymer (e.g., polyimide). Substrate layer  15  may have a thickness of 10 microns to 0.5 mm, may have a thickness of less than 0.2 mm, or may have other suitable thickness (as examples). 
     A thin-film transistor (TFT) layer such as TFT layer  17  may include a layer of thin-film transistor structures (e.g., polysilicon transistors and/or amorphous silicon transistors) formed on substrate layer  15 . 
     An organic emissive layer such as OLED layer  19  may be formed over TFT layer  17 . OLED layer  19  may include a light-emitting material such as an array of organic light-emitting diode structures that are used to form display pixels such as display pixels  30  of  FIG. 5 . 
     A sealant layer such as sealant layer  21  may be formed over OLED layer  19  to protect the structures of OLED layer  19  and TFT layer  17 . Sealant layer  21  may be formed from one or more layers of polymer (e.g., one or more layers of polymer that are deposited onto OLED layer  19 ), metal foil (e.g., a layer of metal foil that is laminated, sputtered, evaporated, or otherwise applied onto OLED layer  19 ), or other suitable coating or conformal covering. 
     Electronic device  10  may be provided with one or more speaker structures for providing sound to a user of electronic device  10 .  FIG. 7  is a cross-sectional side view of a portion of electronic device  10  in the vicinity of a speaker structure such as speaker structure  48 . Sound produced by speaker structure  48  may be transmitted through flexible display  14  to the exterior of device  10 . Flexible display  14  may be used as a speaker membrane structure for speaker  48 . Portions such as portion  14 M that serve as a speaker membrane for speaker  48  may be located in an active or inactive portion of display  14 . Arrangements in which speaker membrane  14 M forms an active display area may allow the size of the active region of flexible display  14  to be increased relative to its inactive region. 
     As shown in  FIG. 7 , speaker structure  48  may be driven by a transducer such as transducer  50 . Transducer  50  may be configured to receive electrical audio signal input from circuitry in device  10  and to convert the electrical signal into sound. In the example of  FIG. 7 , transducer  50  is formed from a magnet such as magnet  40  surrounded by coils such as coils  42 . Magnet  40  may be a permanent magnet formed from ferrite material, ceramic material, iron alloy material, rare earth material, other suitable material, or a combination of these materials. Coils  42  may be formed from copper, aluminum, silver, other suitable materials, etc. If desired, there may be one or more sets of coils surrounding magnet  40 . 
     When current passes through coils  42 , a magnetic field is produced. This allows coils  42  to act as a variable electromagnet with a magnetic field that interacts with the constant magnetic field produced by permanent magnet  40 . For example, the negative pole of the electromagnet may be repelled by the negative pole of permanent magnet  40 . The magnetic force created by this repulsion will force magnet  40  away from coils  42 . When the current flowing through coils  42  changes direction, the polarity of the variable electromagnet reverses. Magnet  40  may be pushed back and forth rapidly (along the z-axis) as the current in coils  42  alternates directions. 
     Portions of flexible display  14  such as portion  14 M may form a speaker membrane for speaker  48 . As magnet  40  moves back and forth along the z-axis, attached speaker membrane  14 M will in turn vibrate the air in front of speaker membrane  14 M, creating sound waves. 
     In some arrangements, an optional support structure such as support structure  46  (sometimes referred to as a stiffening structure or stiffener) may be interposed between transducer  50  and speaker membrane  14 M. Support structure  46  may be used to stiffen speaker membrane portion  14 M of display  14 . Support structure  46  may be formed from a metal plate, from specialized composite structures (e.g., a layer of foam interposed between layers of stiffener, etc.), from other support materials or stiffening structures, or from a combination of these materials. Using a support structure such as support structure  46  may allow speaker membrane  14 M to respond more accurately to the movement of magnet  40 . In arrangements where optional support structure  46  is not used, magnet  40  may be configured to stiffen portion  14 M of display  14  that serves as a speaker membrane structure. 
     There may be one or more speaker structures  48  in device  10 . Some or all of speaker structures  48  in device  10  may have speaker membranes that are formed from flexible display  14 . If desired, some, all, or substantially all of flexible display  14  may be used as a speaker membrane for one speaker, for two speakers, for three speakers, or for more than three speakers. 
     A suspension structure such as suspension structure  54  may be used to attach portions of flexible display  14  to a rigid support structure such as housing  12 . Suspension structure  54  may prevent speaker membrane  14 M from moving laterally along the x-axis and/or the y-axis, but may allow free motion of speaker membrane  14 M along the z-axis as speaker  48  produces sound. Suspension structure  54  may be formed from an elastomeric material, foam material, resin coated material, other suitable materials, or a combination of these materials. As shown in the example of  FIG. 7 , suspension structure  54  may form a pliant interface between speaker membrane  14 M and housing sidewalls  12 S. This is merely illustrative. If desired, suspension structure  54  may form a pliant interface between speaker membrane  14 M and any suitable surrounding housing structure or any suitable rigid support structure. 
     If desired, other suspension structures may be incorporated into speaker structure  48 . For example, there may be one or more suspension structures attached to magnet  40 . This type of suspension structure may provide a restoring force that returns magnet  40  to an equilibrium position after being displaced by magnetic forces. 
     The desired range of frequencies produced by speaker  48  may depend on several factors. For example, the desired range of frequencies produced by speaker  48  may depend on the type of electronic device in which speaker  48  is implemented, may depend on the location of speaker  48  in device  10 , may depend on the other speaker structures that are being used in combination with speaker structure  48 , etc. Design choices may be made to obtain a desired frequency response from speaker  48 . For example, materials used in forming speaker  48  may be selected based on the desired frequency response. 
     The type of enclosure that surrounds speaker  48  may also be selected based on the desired frequency response. For example, the enclosure that surrounds the speaker may be ported. As shown in  FIG. 7 , housing  12  may optionally be provided with an opening or port such as acoustic port  52  (sometimes referred to as a funnel, horn, vent, hole, etc.). Port  52  may be used to equalize the pressure between the inside of housing  12  and the outside of housing  12 . This may in turn augment the sound waves produced by speaker  48 . A ported enclosure such as the ported enclosure shown in the example of  FIG. 7  may increase the magnitude of low-frequency sound waves produced by speaker  48  (e.g., a speaker with a ported enclosure may have a higher bass output than a speaker with a sealed enclosure). 
     As shown in  FIG. 7 , port  52  may have a portion such as portion  52 P that protrudes into the enclosure. The size and shape of protruding portion  52 P may be customized to obtain a desired frequency response. For example, protruding portion  52 P of port  52  may have a “horn” shape, in which the diameter of opening  52  varies along the length of portion  52 P. Protruding portion  52 P may have a curved shape, if desired. In general, protruding portion  52 P may have any suitable shape, and opening  52  may have any suitable size. The characteristics of port  52  will depend on the desired frequency response of speaker  48 , the structure of device  10 , etc., and may be modified accordingly. The example shown in  FIG. 7  is merely illustrative. 
     If desired, speaker  48  may be provided with a sealed enclosure that does not have a port. The example of  FIG. 7  in which housing  12  is provided with port  52  is merely illustrative. The type of enclosure into which speaker  48  is implemented (e.g., a sealed enclosure, a ported enclosure, etc.) will depend on the desired frequency response of speaker  48 , the structure of device  10 , etc., and may be modified accordingly. 
     Electronic device  10  may have internal components or structures such as internal component  56 . Internal components such as internal component  56  may optionally be used to tune the resonant frequency of speaker  48 . Internal component  56  may be a battery or other internal structure. If desired, optional component  56  may be omitted or may otherwise not be used to tune the resonant frequency of speaker  48 . 
     If desired, housing  12  may have one or more raised edges such as optional raised portion  12 ′. Raised portion  12 ′ may have an upper surface that lies above the upper surface of display  14  (e.g., the upper surface of raised portion  12 ′ may protrude above the upper surface of flexible display  14  in vertical dimension z). Optional raised housing  12 ′ may allow a user to hold device  10  in hand without disrupting the speaker functionality of display  14 . Raised portion  12 ′ of housing  12  may surround the entire periphery of display  14 , or may be located on one side of display  14 , on two sides of display  14 , on three sides of display  14 , or on all four sides of display  14 . Raised portion  12 ′ may be formed as an integral part of housing  12  or may be formed as a separate structure in contact with housing  12 . 
       FIG. 8  is a cross-sectional side view of a portion of electronic device  10  in the vicinity of another possible embodiment of speaker structure  48 . As shown in  FIG. 8 , speaker structure  48  may be driven by a transducer such as transducer  50 . In the example of  FIG. 8 , transducer  50  may be formed from one or more central sets of coils  42  surrounded by a magnet such as magnet  40 . In some arrangements, inner portion  44  of coils  42  may also contain a magnet structure (e.g., coils  42  may surround a magnet structure). Magnet structures that are formed within inner portion  44  of coils  42  may be formed as an integral part of outer magnet  40  (e.g., may be joined above and/or below coils  42 ) or may be a separate magnet structure. If desired, inner portion  44  of coils  42  may be free of magnet structures. 
     As with the transducer of  FIG. 7 , transducer  50  of  FIG. 8  may be configured to receive electrical audio signal input from circuitry in device  10  and to convert the electrical signal into sound. As current passes through coils  42 , a magnetic field is produced. The magnetic field produced by coils  42  interacts with the constant magnetic field produced by permanent magnet  40 . The interaction of the electromagnet with the constant magnetic field will create a magnetic force between coils  42  and magnet  40  (e.g., an attractive or repulsive force). When the current flowing through coils  42  changes direction, the polarity of the variable electromagnet (and thus the direction of magnetic force) is reversed. Coils  42  may be pushed back and forth (along the z-axis) by the varying magnetic force as the current in coils  42  alternates directions. 
     As coils  42  move back and forth, attached speaker membrane  14 M will in turn vibrate the air in front of speaker membrane  14 M, creating sound waves. Support structure  46  may be used to stiffen speaker membrane  14 M so that membrane portion  14 M of flexible display  14  responds accurately to the movement of transducer  50 . 
     In the example of  FIG. 8 , speaker  48  may be provided with a sealed enclosure that does not have a port. This is merely illustrative. Any suitable type of enclosure (e.g., a sealed enclosure, a ported enclosure, etc.) may be used. The type of enclosure into which speaker  48  is implemented will depend on the desired frequency response of speaker  48 , the structure of device  10 , etc., and may be modified accordingly. 
       FIG. 9  is a cross-sectional side view of a portion of device  10  in the vicinity of another possible embodiment of speaker structure  48 . In the example of  FIG. 9 , speaker  48  is supported by a rigid structure within device  10  such as rigid structure  66 . Rigid structure  66  may be formed from housing structures or internal components, or may be a dedicated structure used to form a frame (sometimes referred to as a chassis or “basket”) or other rigid support structure for speaker  48 . Suspension structure  54  may be used to form a pliant interface between speaker  48  and rigid structure  66 . As with the suspension structure of  FIGS. 7  and  8  (in which suspension structure  54  is attached to housing sidewalls  12 S), suspension structure  54  of  FIG. 9  may prevent speaker membrane portions  14 M of display  14  from moving laterally along the x-axis and/or the y-axis, but may allow free motion of speaker membrane  14 M along the z-axis as speaker  48  produces sound. Suspension structure  54  may be attached to any suitable portion of speaker  48  (e.g., support structure  46 , magnet  40 , speaker membrane portion  14 M, etc.) 
     The type of arrangement shown in  FIG. 9  may be beneficial for configurations in which speaker  48  is not in the vicinity of housing sidewalls  12 S or in other configurations in which speaker  48  is not attached to housing  12 . For example, speaker  48  may be located in the central portion of a large display. In this type of configuration, a rigid structure such as rigid structure  66  of  FIG. 9  may be used to support speaker  48 , if desired. 
     There may be one or more speakers  48  in device  10 . Multiple speakers  48  may be attached to a common rigid structure  66  or each speaker  48  may be attached to a separate rigid structure  66 . 
     If desired, a cover layer such as optional cover layer  62  may be formed over flexible display  14 . Cover layer  62  may be formed from glass, plastic, or other suitable material. Cover layer  62  may allow a user to hold device  10  in hand without disrupting the speaker functionality of display  14 . Cover layer  62  may also serve to protect display  14  and other parts of device  10  while still allowing speaker membrane  14 M to move freely along the z-axis as speaker  48  produces sound. Cover layer  62  may be in contact with display  14  or there may be a gap  63  interposed between cover layer  62  and display  14 . Gap  63  may be filled with air or may include a layer of material such as a layer of sealant (as an example). 
     One or more holes such as holes  64  (sometimes referred to as openings or speaker openings) may be formed in cover layer  62  so that sound may pass from speaker  48  to the exterior of device  10 . 
     A perspective view of device  10  showing how holes  64  may be formed in cover layer  62  is shown in  FIG. 10 . As shown in  FIG. 10 , holes  64  may be formed in a “speaker grill” fashion in which an array of openings is formed in front of one or more speakers. Holes  64  may be formed in cover layer  62  in any suitable location. For example, holes  64  may be formed in localized areas of cover layer  62  that overlap a speaker structure, or holes  64  may be formed in a uniform array that covers some, all, or substantially all of the front surface of display  14 . Holes  64  may have any suitable size. For example, holes  64  may have a diameter between 0.25 mm and 0.5 mm, between 0.5 mm and 1 mm, between 1 mm and 1.5 mm, more than 1.5 mm, less than 1.5 mm, etc. The size, shape, and number of openings  64  formed in cover layer  62  may depend on the type and number of speakers  48  in device  10 . 
       FIG. 11  is a cross-sectional side view of device  10  in the vicinity of support structure  46 . Support structure  46  may be used to stiffen portions of flexible display  14 . As discussed in connection with  FIG. 7 , stiffening structure  46  may be formed from a metal plate, from fiber-based composite materials, from laminated layers of one or more materials, or from other suitable materials. As shown in the example of  FIG. 11 , stiffening structure  46  may be formed from a layer of foam  74  interposed between first and second stiffening sheets  72 . Sheets  72  may be formed from polymer, metal, glass, ceramic, fiber-based composites, or other suitable materials. This type of structure may provide a stiff and lightweight support structure for display  14 . If desired, support structure  46  may be used to stiffen speaker membrane portions  14 M of display  14 , may be used to stiffen other portions of display  14 , or may be used to stiffen all or substantially all of display  14 . 
     Support structure  46  may be shaped in any desired fashion. For example, support structure  46  may be curved, may be planar, or may have a combination of curved and planar portions. 
       FIG. 12  is a cross-sectional side view of device  10  in the vicinity of curved support structure  46 . As shown in  FIG. 12 , flexible display  14  may conform to the shape of stiffening structure  46 . In the example of  FIG. 12  stiffening structure  46  has a curved shape so that flexible display  14  is concave. This is, however, merely illustrative. In general, stiffening structure  46  and the attached portion of display  14  may have any suitable shape. For example, stiffening structure  46  may have a curved shape so that flexible display  14  is convex. The example of  FIG. 12  in which display  14  has a concave shape may be suitable for configurations in which display  14  forms a speaker membrane for speaker  48 . A concave shaped speaker membrane may improve the quality of sound produced by speaker  48 . Speakers with convex membranes may also be used. 
       FIG. 13  is a cross-sectional side view of device  10  in the vicinity of a single speaker structure. As shown in  FIG. 13 , portion  14 M of flexible display  14  may form a speaker membrane for speaker structure  48 . Transducer  50  for speaker  48  may be any suitable type of transducer (e.g., one or more sets of coils surrounded by a magnet, one or more sets of coils surrounding a magnet, a piezoelectric transducer, a microphone transducer, a sensor, an actuator, etc.). Speaker  48  may be the only speaker in device  10  or may be one of a plurality of speakers in device  10 . Display-based speaker structure  48  may be used in conjunction with speaker structures that are not display-based. For example, there may be other speakers in device  10  which do not use display  14  as a speaker membrane. Speaker structure  48  of  FIG. 13  may use all or substantially all of display  14  as a speaker membrane (e.g., the entire front face of device  10  may be occupied by a speaker), or may use only a portion of display  14  as a speaker membrane. 
     In the example of  FIG. 14 , an array of transducers  50  may be used to form a plurality of display-based speakers  48 . Display-based speaker structures  48  may be used in conjunction with speaker structures that are not display-based. Each display-based speaker  48  may have an associated transducer  50 . Each associated transducer  50  may be any suitable type of transducer (e.g., one or more sets of coils surrounded by a magnet, one or more sets of coils surrounding a magnet, a piezoelectric transducer, a microphone transducer, a sensor, an actuator, etc.). The type of transducer  50  used may be different for each speaker (e.g., the array of speakers  48  in  FIG. 14  may include different types of transducers, if desired). Providing speakers  48  with different types of transducers, different structures, and different characteristics may give device  10  the ability to produce sound with a wider range of frequencies. 
       FIG. 15  is a bottom view of a portion of device  10  showing how an array of display-based speakers such as the array shown in  FIG. 14  may be implemented in device  10 . In the example of  FIG. 15 , support structure  46  is formed on the underside of display  14 . Support structure  46  may be used to stiffen speaker membrane portions  14 M of display  14  (e.g., support structure  46  may be interposed between transducer  50  and display  14 ). Support structure  46  may also be used to stiffen portions of display  14  between adjacent speakers  48 . 
     Each speaker  48  may be surrounded by a ring  14 ′ of flexible display  14  that is not stiffened by support structure  46 . Flexible ring-shaped portions  14 ′ of flexible display  14  may provide a barrier structure around each speaker  48  that prevents interference between adjacent speakers  48 . For example, as speaker membrane  14 M vibrates, ring  14 ′ (which is surrounded by support structure  46 ) may absorb vibrations moving laterally in display  14  (e.g., in directions along the x-axis and/or y-axis). This may allow adjacent speakers  48  to operate independently without being disrupted by the vibrations of a neighboring speaker. 
     If desired, speakers  48  may include a variety of speaker types. Examples of speaker types that may be used for speakers  48  include subwoofers, woofers, mid-range speakers, tweeters, supertweeters, etc. If desired, different channels of audio input may be routed to each speaker. For example, speakers  48  may include a center channel speaker, a left channel speaker, a right channel speaker, a surround channel speaker, etc. Any suitable characteristic of speakers  48  (e.g., size, type, location, input channel, etc.) may be modified to achieve a desired frequency response and/or to accommodate the structure of device  10 . 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20120316
Publication Date: 20150113
Grant Date: 20150113
Priority Date: 20110321
Inventors: FRANKLIN JEREMY C.
ROTHKOPF FLETCHER R.
MYERS SCOTT A.
LYNCH STEPHEN BRIAN
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F1/1652", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/02", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1652", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2499/15", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/028", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/02", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/028", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1688", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1652", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/028", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2499/15", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2499/15", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1688", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 46877380