PATENT DOCUMENT

Publication Number: US-8374378-B2
Application Number: US-201213458539-A
Country: US
Kind Code: B2

Title: Portable computer speaker grill structures

Abstract:
Portable computer structures are provided. The portable computer structures may include speaker grill structures. A speaker grill structure may be formed by creating an array of small holes (perforations) in a portable computer housing structure such as a planar housing wall. A speaker may be mounted adjacent to the array of holes. The planar housing wall may be formed in a block of milled aluminum and may have a thickness of less than 1 mm. The speaker holes may have with small diameters without overly attenuating sound from a speaker.

Claims:
1. A portable computer, comprising:
 a metal housing wall having a speaker grill region in which an array of speaker holes is formed, wherein the metal housing wall has a thickness, in the speaker grill region, of less than 1 mm and wherein each speaker hole has a diameter between approximately 0.25 mm and 0.5 mm; and 
 a speaker driver adjacent to the array of speaker holes. 
 
     
     
       2. The portable computer defined in  claim 1  wherein the metal housing wall includes at least a given region that is adjacent to the speaker grill region and wherein the thickness of the metal housing wall in the given region is greater than the thickness of metal housing wall in the speaker grill region. 
     
     
       3. The portable computer defined in  claim 1  wherein each of the speaker holes has an aspect ratio defined by the thickness of the metal housing wall in the speaker grill region divided by the diameter of that speaker hole and wherein the aspect ratio of each of the speaker holes is approximately three to one. 
     
     
       4. The portable computer defined in  claim 1  wherein each of the speaker holes has an aspect ratio defined by the thickness of the metal housing wall in the speaker grill region divided by the diameter of that speaker hole and wherein the aspect ratio of each of the speaker holes is approximately two to one. 
     
     
       5. The portable computer defined in  claim 1  wherein the thickness of the metal housing wall in the speaker grill region is less than or equal to 0.75 mm. 
     
     
       6. The portable computer defined in  claim 1  wherein the speaker holes are spaced apart from each other with a pitch of about 0.25 mm to 0.5 mm. 
     
     
       7. The portable computer defined in  claim 1  further comprising:
 keys in the metal housing wall, wherein the keys form a keyboard for the portable computer and wherein some of the keys are adjacent to the array of speaker holes. 
 
     
     
       8. The portable computer defined in  claim 1  wherein the speaker grill region comprises a first speaker grill region in which a first array of speaker holes is formed, wherein the metal housing wall comprises a second speaker grill region in which a second array of speaker holes is formed. 
     
     
       9. The portable computer defined in  claim 8  wherein each speaker hole in the second array of speaker holes has a diameter between approximately 0.25 mm and 0.5 mm and wherein the second speaker grill region has a thickness of less than 1 mm. 
     
     
       10. The portable computer defined in  claim 1  further comprising:
 a speaker enclosure in which the speaker driver is mounted; and 
 a layer of mesh between the array of speaker holes and the speaker enclosure. 
 
     
     
       11. The portable computer defined in  claim 1  further comprising:
 at least one bass speaker, wherein the bass speaker is mounted within the portable computer so that the bass speaker is not under any speaker holes in the metal housing wall. 
 
     
     
       12. The portable computer defined in  claim 1  further comprising:
 a first speaker enclosure in which the speaker driver is mounted; and 
 a bass speaker mounted in a second speaker enclosure, wherein the bass speaker is mounted within the portable computer so that the bass speaker is not under any speaker holes in the metal housing wall and wherein the first and second speaker enclosures are connected so that sound passes from the second speaker enclosure to the first speaker enclosure. 
 
     
     
       13. A portable computer, comprising:
 a metal housing wall having a speaker grill region in which an array of speaker holes is formed, wherein the speaker holes are spaced apart from each other with a pitch of approximately 0.25 mm to 0.5 mm; and 
 a speaker driver adjacent to the array of speaker holes. 
 
     
     
       14. The portable computer defined in  claim 13  wherein the metal housing wall has a thickness, in the speaker grill region, of less than 1 mm. 
     
     
       15. The portable computer defined in  claim 13  wherein the metal housing wall has a thickness, in the speaker grill region, of less than 1 mm such that the metal housing wall attenuates sound, within a range of 500 Hz to 10 kHz, from the speaker driver that passes through the metal housing wall by no more than approximately 3 dB. 
     
     
       16. The portable computer defined in  claim 13  wherein the array of speaker holes comprises an array of at least 5000 speaker holes. 
     
     
       17. A portable computer, comprising:
 a milled aluminum block including a planar metal housing wall with an array of speaker holes, each speaker hole having a diameter between approximately 0.25 mm and 0.5 mm; and 
 a speaker driver adjacent to the array of speaker holes. 
 
     
     
       18. The portable computer defined in  claim 17 , wherein the planar metal housing wall has a thickness of less than 1 mm. 
     
     
       19. The portable computer defined in  claim 18  further comprising a layer of mesh adjacent to the array of speaker holes, wherein the speaker holes comprise laser-drilled holes in the milled aluminum block. 
     
     
       20. The portable computer defined in  claim 19  wherein the speaker holes are spaced apart from each other with a pitch of about 0.25 mm to 0.5 mm.

Description:
This application is a continuation of patent application Ser. No. 12/340,626, filed Dec. 19, 2008 now U.S. Pat. No. 8,170,266, which claims the benefit of provisional patent application No. 61/105,036, filed Oct. 13, 2008, 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. 12/340,626, filed Dec. 19, 2008 and provisional patent application No. 61/105,036, filed Oct. 13, 2008. 
    
    
     BACKGROUND 
     This invention relates to electronic devices and, more particularly, to audio structures such as speaker grill structures for electronic devices such as portable computers. 
     Designers of portable computer speaker enclosures are faced with competing demands. Speaker grills should allow sound to be freely emitted from within a portable computer. At the same time, a speaker grill cannot be too porous. Speaker grills that have openings that are too large may fail to properly protect speakers from damage and may not be able to prevent the intrusion of foreign matter to the interior of the computer. 
     It would therefore be desirable to be able to provide improved audio structures such as speaker grill structures for electronic devices such as portable computers. 
     SUMMARY 
     Electronic devices such as portable computers with improved audio structures such as speaker grill structures are provided. An electronic device may have a case in which speaker grill structures are formed. Each speaker grill structure may be formed by creating an array of small holes (perforations) in the case of the device. 
     The size and spacing (pitch) of the holes created in the case to form a speaker grill structure may be selected such that the speaker grill structure passes sound waves with a minimal impact on the amplitude (e.g., sound pressure level) of the sound waves. For example, the size and spacing of the holes may be selected such that the speaker grill structure reduces the sound pressure of the sound waves by less than three decibels within an audio frequency range of interest. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device such as a portable computer in accordance with an embodiment of the present invention. 
         FIG. 2  is a perspective view of an interior portion of a housing for a portable computer showing illustrative speaker structures that may be used in the portable computer in accordance with an embodiment of the present invention. 
         FIG. 3  is an exploded perspective view of the illustrative speaker and housing structures for a portable computer in accordance with an embodiment of the present invention. 
         FIG. 4  shows the interior of a portable computer housing structure having illustrative speaker grill structures that may be formed on the surface of the housing structure and associated speaker drivers that may generate sound that passes through the speaker grill structures in accordance with an embodiment of the present invention. 
         FIG. 5  is a top view of a portion of an illustrative portable computer case in which a speaker grill structure has been formed from an array of small holes in accordance with an embodiment of the present invention. 
         FIG. 6  is a graph of audio pass-through characteristics for illustrative speaker grills as a function of pitch and hole size in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional perspective view of an illustrative speaker grill structure that may be formed in a portable computer housing that has been milled from a solid block of metal in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention relates to audio structures for electronic devices. Speaker structures may be provided that protect a speaker that is mounted within the interior of an electronic device from damage while allowing sound to pass between the interior and exterior of the device. 
     The electronic device in which the speaker structures are formed may be a handheld computer, a miniature or wearable device, a portable computer, a desktop computer, a mobile telephone, a music player, a remote control, a global positioning system device, devices that combine the functions of one or more of these devices and other suitable devices, or any other electronic device. With one suitable arrangement, which is sometimes described herein as an example, the electronic devices in which the speaker structures are provided may be portable computers such as laptop (notebook) computers. This is, however, merely illustrative. Speaker structures may, in general, be provided in any suitable electronic device. 
     An illustrative electronic device such as a portable computer in which speaker structures may be provided is shown in  FIG. 1 . As shown in  FIG. 1 , portable computer  10  may have a housing  12 . Housing  12 , which is sometimes referred to as a case, may be formed from one or more individual structures. For example, housing  12  may have a main structural support member that is formed from a solid block of machined aluminum or other suitable metal. One or more additional structures may be connected to the housing  12 . These structures may include, for example, internal frame members, external coverings such as sheets of metal, etc. Housing  12  and its associated components may, in general, be formed from any suitable materials such as such as plastic, ceramics, metal, glass, etc. An advantage of forming housing  12  at least partly from metal is that metal is durable and attractive in appearance. Metals such as aluminum may be anodized to form an insulating oxide coating. 
     Housing  12  may have an upper portion  26  and a lower portion  28 . Lower portion  28  may be referred to as the base or main unit of computer  10  and may contain components such as a hard disk drive, battery, and main logic board. Upper portion  26 , which is sometimes referred to as a cover or lid, may rotate relative to lower portion  28  about rotational axis  16 . Portion  18  of computer  10  may contain a hinge and associated clutch structures and is sometimes referred to as a clutch barrel. 
     Lower housing portion  28  may have a slot such as slot  22  through which optical disks may be loaded into an optical disk drive. Lower housing portion may also have a touchpad such as touchpad  24  and may have keys  20 . If desired, additional components may be mounted to upper and lower housing portions  26  and  28 . For example, upper and lower housing portions  26  and  28  may have ports to which cables can be connected (e.g., universal serial bus ports, an Ethernet port, a Firewire port, audio jacks, card slots, etc.). Buttons and other controls may also be mounted to housing  12 . 
     If desired, upper and lower housing portions  26  and  28  may have transparent windows through which light may be emitted (e.g., from light-emitting diodes). This type of arrangement may be used, for example, to display status information to a user. 
     Openings may be formed in the surface of upper and lower housing portions to allow sound to pass through the walls of housing  12 . For example, openings may be formed in housing walls for microphone and speaker ports (collectively “audio ports”). Speaker openings such as speaker openings (e.g., speaker grill structures  30 ) may be formed in lower housing portion  28  by creating an array of small openings (perforations) in the surface of housing  12 . 
     A display such as display  14  may be mounted within upper housing portion  26 . Display  14  may be, for example, a liquid crystal display (LCD), organic light emitting diode (OLED) display, or plasma display (as examples). A glass panel may be mounted in front of display  14 . The glass panel may help add structural integrity to computer  10 . For example, the glass panel may make upper housing portion  26  more rigid and may protect display  14  from damage due to contact with keys or other structures. 
     Computer  10  may have input-output components such as touch pad  24 . Touch pad  24  may include a touch sensitive surface that allows a user of computer  10  to control computer  10  using touch-based commands (gestures). A portion of touchpad  24  may be depressed by the user when the user desires to “click” on a displayed item on screen  14 . 
     A perspective view of an illustrative housing portion  28  having speaker structures that may be used in computer  10  is shown in  FIG. 2 . As shown in  FIG. 2 , speaker enclosures such as speaker enclosures  32 ,  34 , and  38  may be mounted within lower housing portion  28 . With one suitable arrangement, speaker enclosures  32  and  34  may be mounted beneath speaker openings  30  (e.g., speaker grill structures  30  for speaker ports). 
     Speaker enclosures in device  10  such as speaker enclosures  32 ,  34 , and  38  may contain one or more speaker drivers (e.g., speakers). For example, driver  36  may be mounted in enclosure  34 . Drivers such as driver  36  may be mounted in speaker enclosures using any suitable method such as screws, adhesive, etc. If desired, one or more speaker enclosures in device  10  may be configured to produce sound at particular frequencies. As an example, a speaker enclosure may contain one or more speakers configured to produce sound at relatively low frequencies. With one suitable arrangement, one or more speakers such as woofers and mid-range drivers (collectively “bass speakers”) may be mounted in speaker enclosure  38 . 
     As illustrated by  FIG. 2 , speaker enclosure  38  may not be mounted beneath a speaker opening in the housing of device  10 . In this type of arrangement, speaker enclosure  38  can be connected to speaker enclosure  34  (e.g., through an interior passage between the two respective enclosures or using other suitable coupling structures). When the speaker enclosures are connected in this way, sound that is generated by a driver in enclosure  38  travels through enclosures  38  and  34  and exits device  10  through opening  30 . 
     Paths such as electrical paths  33  and  40  may be used to electrically connected speaker drivers in speaker enclosures  32 ,  34 , and  38  to circuitry in device  10 . For example, paths  33  and  40  may connect to audio amplifier circuitry in device  10  to transmit amplified power signals between the audio amplifier circuitry and speaker drivers such as driver  36 . 
       FIG. 3  shows an exploded perspective view of speaker enclosures  32 ,  36 , and  38  of  FIG. 2 . As shown in  FIG. 3 , device  10  may have mesh structures between openings  30  and enclosures  32 ,  34 , and  38 . For example, mesh  42  may be interposed between enclosure  34  and its associated opening  30  and mesh  44  may be interposed between enclosure  32  and its associated speaker opening  30 . 
     Mesh  42  and mesh  44  may be, for example, speaker meshes that are mounted to lower housing portion  28  with adhesive. Speaker mesh, which may sometimes be referred to as acoustic mesh, may be formed from plastic, metal, or other suitable materials. With one suitable arrangement, speaker meshes  42  and  44  may serve to improve the exterior aesthetic appearance of device  10  without impeding the passage of sound waves from speaker enclosures and drivers to the exterior of device  10  through openings  30 . Speaker meshes  42  may improve the aesthetic appearance of device  10  by preventing a user of device  10  from being able to see through openings  30  to speaker enclosures  32 ,  34 , and  38  and/or speaker drivers such as driver  36 . 
       FIG. 4  illustrates how speaker grill structures  30  can allow sound from speaker enclosures  32 ,  34 , and  38  to escape from within device  10  (e.g., from within lower housing portion  28 ). Each of the speaker enclosures may have one or more speaker drivers. For example, driver  35  may be mounted within enclosure  32 , driver  36  may be mounted within enclosure  34 , and driver  39  may be mounted within enclosure  38 . 
     As shown in  FIG. 4 , speaker enclosure  38  may contain a driver such as driver  39  that is not directly beneath a speaker grill structures such as one of structures  30  in device  10 . With one suitable arrangement, sound waves produced by driver  39  may be transmitted from within enclosure  38  to enclosure  34  (e.g., sound waves may be transmitted from enclosure  38  to enclosure  34  because the enclosures are firmly connected together) and then out of enclosure  34  through the speaker grill structure associated with enclosure  34 . 
     Other components of device  10  may also be mounted within lower housing portion  28 . For example, a battery may be mounted in region  48  of lower housing portion  28  and a hard disk drive may be mounted within region  46  of lower housing portion  28 . 
     With one suitable arrangement, each speaker grill structure  30  may be formed from an array of small openings (perforations) in lower housing portion  28  of device  10 . Any suitable number of perforations in housing portion  28  may be used to form each speaker grill  30 . For example, each grill  30  may be formed from 100 holes or more, 500 holes or more, 1000 holes or more, 5000 holes or more, 7500 holes or more, 10000 holes or more, more than ten thousand holes, etc. 
     While speaker grills  30  are described herein as an array and are illustrated as a relatively large number of holes which are vertically and horizontally aligned, holes in housing portion  28  which form speaker grills  30  do not, in general, need to be formed in an array and can be formed using any suitable pattern. If desired, the holes that are made in housing portion  28  to form speaker grills  30  may be formed in an off-set array pattern in which each row of holes is slightly offset from the vertically adjacent rows of holes. With another suitable arrangement, holes that are made in housing portion  28  to form speaker grills  30  may be formed randomly or in other patterns. 
     As shown in  FIG. 5 , with one suitable arrangement, the holes that form speaker grills  30  may be relatively uniform in size, shape, and location relative to each other. Each hole may have any suitable diameter  50 , may be spaced at any suitable horizontal distance  52  from other holes, and may be spaced at any suitable vertical distance  53  from other holes that form grills  30 . For example, each hole may have a diameter such as diameter  50  of approximately 0.35 millimeters (i.e., more than 0.3 mm and less than 0.4 mm) and the centers of each holes may be 0.917 millimeters (e.g., 0.8 mm to 1.0 mm) apart in the horizontal direction (e.g., as illustrated by horizontal pitch  52 ) and may be 0.913 millimeters (e.g., 0.8 mm to 1.0 mm) apart in the vertical direction (e.g., as illustrated by vertical pitch  53 . The array of holes that form each speaker grill structure  30  may also have any suitable width  54  and length  55 . For example, each speaker grill structure  30  may be formed from an array of perforations in lower housing portion  28  that span a vertical distance of 103.125 millimeters (e.g., 80 mm to 120 mm) and that span a horizontal distance of 29.348 millimeters (e.g., 20 mm to 40 mm) as illustrated by array length  55  and array width  54 . 
     If desired, the size and the pitch of holes that form speaker grill structures  30  may be configured to optimize the performance of the speaker grills. For example, the size (diameter) of each of the speaker grill holes and the horizontal and vertical separation between each hole (e.g., the pitch of the holes) may be selected using a graph such as the graph of  FIG. 6 . 
     Line  56  in the graph of  FIG. 6  may separate region  57  from region  59  of the  FIG. 6  graph. Region  57  of the  FIG. 6  graph represents a physically impossible configuration in which the diameter of the holes is larger than the separation between the centers of each of the holes. If speaker grill structures were formed from holes with sizes and pitches in region  57 , the speaker grill structures would essentially be a single opening and not a collection of holes. 
     When a speaker grill structure such as grill  30  is formed from holes with properties that lie in region  59 , the speaker grill structure may have suitable audio properties for use in an electronic device such as a portable computer. In particular, a speaker grill having the properties of region  59  may allow sound to pass through with a loss of sound pressure (volume) of no more than three decibels (dBs) in a desired frequency range (e.g., from about 20 Hz, 50 Hz, 100 Hz, 200 Hz, 500 Hz or other suitable low-frequency value to up to about 10 kHz, 15 kHz, 20 kHz, or other suitable high-frequency value). 
     Frequencies within audio ranges such as these (e.g., between 500 Hz and 10 kHz) fall within the normal range of human hearing and can be reproduced by portable computer speakers. Frequencies outside of these normal human audio ranges need not generally be reproduced and are of less interest. For example, the upper range of adult human hearing tends to decrease with age, so frequencies above 10 kHz (and even more so above 20 kHz) are not generally necessary in a portable device. Very low frequencies (e.g., 20 Hz and below) can be difficult or impossible to reproduce in a small speaker, so computer users are not expecting sound reproduction in this frequency range. Because of these considerations, a typical frequency range of interest for a computer speaker may be about 500 Hz to 10 kHz (as an example). Suitable configurations for grill  30  will not overly attenuate sound within this type of normal human hearing frequency range. For example, grill  30  may be configured to introduce no more than about 3 dB (50%) of sound level attenuation at any given frequency within a range of 500 Hz to 10 kHz range (or other suitable range) by following the holes size and spacing limits imposed by region  59 . If a different desired attenuation limit is changed (e.g., to 2 dB or 4 dB) and/or if the frequency range of interest is changed (e.g., to have an upper limit of 15 kHz), the hole size and spacing limits of  FIG. 6  may be adjusted, accordingly. 
     Line  58  may separate region  59  from region  60  of the  FIG. 6  graph. Speaker grill structures formed from holes with properties that lie in region  59  will tend to pass sound with a loss of less than three dBs of sound pressure (e.g., within a range of 500 Hz to 10 kHz range or other suitable audio range associated with normal human hearing). Speaker grill structures formed from holes with properties that lie in region  60  will tend to exhibit more than three dBs of sound pressure loss for at least some of these frequencies. 
     In order to ensure that speaker grill structures  30  perform satisfactorily, the graph of  FIG. 6  may be used to determine an acceptable diameter and a pitch for holes that are used to form the speaker grill structure. As an example, the graph of  FIG. 6  may be used to determine what combination of hole size and pitch (e.g., separation between holes) can be used to form a speaker grill structure which performs to a given standard (e.g., a speaker grill structure which passes sound with a loss of less than a given amount such as 1 dB, 2 dB, 3 dB, 4 dB, etc). An acceptable hole size may be, for example, greater than about 0.25 mm. An acceptable pitch may be greater than about 0.25 mm (for the smallest hole sizes). Larger holes (e.g., with diameters greater than 1 mm) may be acceptable for handling audio, but may have undesirable aesthetics. It may therefore be desirable if the hole size is about 0.25 mm to 0.5 mm and the pitch is about 0.25 mm to 1 mm (as an example). 
       FIG. 7  shows that holes  62  which are made in lower housing portion  28  to form speaker grill structures  30  may have an aspect ratio defined by the depth of the holes (e.g., depth  64 ) divided by the width of the holes (e.g., diameter  66 ). In general, holes  62  of structures  30  may have an aspect ratio of any suitable magnitude such as one-half to one, one to one (e.g., an equal depth and width), two to one, three to one, etc. 
     Lower housing portion  28  of device  10  may be milled from a solid block of metal. For example, housing portion  28  may be formed from a solid block of aluminum that is milled by a computer-controlled milling machine (e.g., a CNC). By milling housing portion  28  from a solid block of metal, the thickness of housing portion  28  in the regions corresponding to speaker grill structures  30  may be adjusted relative to the nominal thickness and dimension of the structures and planar surfaces in housing portion  28 , if desired. With one suitable arrangement, the thickness of housing  28  in the regions corresponding to structures  30  may be 0.75 millimeters or less (e.g., less than 1 mm). When the thickness of speaker grill structures  30  is reduced, the aspect ratio of the holes that make up structures  30  will be decreased. This prevents sound from being blocked by holes with excessive aspect ratios. In addition, when the depth of holes  62  in structures  30  is reduced, it may take less time to form holes  62  in structures  30 . In contrast, while deeper holes  62  may require additional time to form in structures  30 , deeper holes  62  will generally provide structures  30  with increased structural integrity. By selecting an appropriate thickness for the regions of housing  28  corresponding to speaker grill structures  30 , the time required for form holes  62  may be optimized without compromising the structural integrity of structures  30 . 
     Holes  62  may be formed using any suitable method. With one arrangement, holes  62  are formed using laser drilling to remove portions of housing  28  corresponding to holes  62 . For example, one or more laser beams may be used to drill holes  62  in housing  28 . Beams of laser light may be shined at the locations of holes  62  in housing  28  and, if desired, the beams may be steered using mirrors or other suitable methods and/or by translating the lasers and/or workpiece to form all of the holes in each speaker grill structure  30 . Holes  62  may also be formed using a gang drilling method (e.g., using multiple mechanical drills), stamping, or other suitable method. 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20120427
Publication Date: 20130212
Grant Date: 20130212
Priority Date: 20081013
Inventors: HOPKINSON RON
RAFF JOHN
ANDRE BARTLEY K.
LIGTENBERG CHRIS
GOEL RUCHI
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R1/023", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/023", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 42098877