Abstract:
The present invention provides exemplary laptop computers having flat panel speakers. In one embodiment, a portable computer ( 10 ) is provided comprising a base ( 12 ) having a processor ( 14 ) and a lid assembly ( 16 ) hingedly connected to the base. The lid assembly has a front side ( 20 ) containing a display ( 24 ), and a back side ( 22 ), preferably having a recessed area ( 26 ). The computer includes at least one flat panel speaker assembly fixedly attached to the back side, preferably within the recessed area, and in electrical communication with the processor. In this manner, the flat panel speaker assembly is firmly attached to the lid assembly and does not need to be rotated or otherwise moved with respect to the lid assembly for exemplary audio quality.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to laptop or portable computers and, more specifically, to laptop or portable computers having flat panel speakers. 
     Laptop computers traditionally have used fixed directional speakers located in the base of the laptop adjacent the keyboard. These speakers are subject to the typical limitations of piston-driven speakers. For example, off-axis sound quality decreases, and the sound volume decreases in accordance with the inverse square law. With the increased use of computers for multi-media applications, it is desirable to provide improved speakers and hence better sound quality for laptop computers. 
     Recent developments in flat panel speaker technology, particularly by New Transducer Ltd. (NXT) located in Stonehill, Huntingdon England, present the possibility of using flat panel speakers with laptop computers. For example, PCT Application No. PCT/GB96/02142 (Int&#39;l. Pub. No. WO 97/09854) discloses a laptop computer using pull-out loud speakers. Such speakers, however, have several limitations which it would be desirable to avoid. Namely, it is desirable to provide fixed speakers capable of omni-directional audio output without having to move or rotate the speakers. Moving or rotating speakers presents the possibility of breakage of the hinges or speakers, particularly since it is common for laptop computers to be used in tight confines, such as in the coach section of airplanes. 
     SUMMARY OF THE INVENTION 
     The present invention provides exemplary laptop computers with flat panel speakers that overcome at least some of the shortcomings of the prior art. In one exemplary embodiment of the present invention, a portable computer is provided comprising a base having a processor. A lid assembly is hingedly connected to the base. The lid assembly has a front side containing a display, such as a liquid crystal display, and a back side. The computer includes at least one flat panel speaker assembly fixedly attached to the back side and in electrical communication with the processor. In this manner, the flat panel speaker assembly is firmly attached to the lid assembly and does not need to be rotated or otherwise moved with respect to the lid assembly for exemplary sound quality. 
     The flat panel speaker assemblies preferably reside in either a recessed area located within the back side or are fixedly attached to a cover covering the recessed area. An attachment mechanism fixedly attaches the speaker assemblies to a mounting surface on the back side of the lid assembly. In one aspect, the speaker assembly is mounted so that a flat panel of the speaker assembly is suspended above the mounting surface. In this manner, a gap is formed between the mounting surface and a portion of the flat panel speaker assembly to assist the production of high quality audio output. 
     Other features and advantages of the invention will appear from the following description in which the preferred embodiment has been set forth in detail in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A depicts an overall view of a portable computer according to the present invention; 
     FIG. 1B depicts an overall view of the back side of a lid assembly of the portable computer shown in FIG. 1A; 
     FIG. 1C depicts an overall view of a recessed area cover for use with the portable computer shown in FIGS. 1A-1B; 
     FIG.  2 A and FIG. 2B depict front plan views of an exemplary flat panel speaker assembly; 
     FIG.  3 A and FIG. 3B depict an exploded side cross sectional view and a cross sectional view of the speaker assembly shown in FIG. 2, respectively; 
     FIG. 4A depicts the back side of the lid assembly shown in FIG. 1B having flat panel speakers residing within the recessed area; 
     FIG. 4B depicts flat panel speaker assemblies attached to the recessed area cover according to the present invention; 
     FIGS. 5A-5C depict alternative attachment mechanisms attaching the speaker assembly to a mounting surface; 
     FIGS. 6A-6D depict front plan views of the speaker assembly showing positioning of attachment points; and 
     FIG. 7 depicts an alternative embodiment of a speaker assembly attachment mechanism for use with the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1A and 1B depict a portable computer  10  having a base  12  containing a processor  14 . A lid assembly  16  is hingedly connected to base  12  using at least one hinge  18 . Lid assembly  16  includes a display  24 , such as a liquid crystal display, located on a front side  20  of lid assembly  16 . Lid assembly  16  has a back side  22 , as best shown in FIG. 1B, which includes a recessed area  26  therein. A recessed area cover  28 , as shown in FIG. 1C, preferably encloses recessed area  26 . Computer  10  includes at least one flat panel speaker assembly  30  fixedly attached to back side  22  as further described in conjunction with later figures. 
     Exemplary flat panel speakers for use with the present invention may be acquired from New Transducers Ltd. located in Stonehill, Huntingdon England and are further described in PCT Application Nos. PCT/GB96/02151 (Int&#39;l. Pub. No. WO 97/09852), PCT/GB96/02167 (Int&#39;l. Pub. No. WO 97/09859) and PCT/GB96/02160 (Int&#39;l. Pub. No. WO 97/09861), the complete disclosures of which are herein incorporated by reference. At least part of the present invention is the recognition that flat panel speakers may be integrated into a laptop lid assembly to provide exemplary audio output for multi-media applications. 
     As shown in FIGS. 2A and 2E, speaker assembly  30  includes a panel  32 , preferably comprising rohacell, carbon fiber, or the like. Speaker assembly  30  further has an exciter package  34  for producing vibrations within panel  32 . Exciter package  34  is mounted wholly and exclusively on or in panel  32  at a predetermined location to launch bending waves into panel  32  to cause panel  32  to resonate to radiate an acoustic output. Exciter package  34  is driven by a signal amplifier, e.g., an audio amplifier, connected to the exciter package  34  by conductors (not shown). Exciter package  34  is then connected to processor  14  to receive audio commands. Exciter package  34  preferably is positioned slightly off center with respect to panel  32 . In one particular embodiment, exciter package  34  is positioned as depicted in FIG. 2B on panel  32  having a surface area that is about 74 millimeters by about 65 millimeters. It will be appreciated by those skilled in the art that other panel  32  shapes and dimensions are possible within the scope of the present invention. 
     Speaker assembly  30  is further described in conjunction with FIGS. 3A and 3B which depict an exploded side cross sectional view and an assembled cross sectional view, respectively. Speaker assembly  30  includes panel  32 , a suspension gasket  35  and a base  44 . Exciter package  34  comprises a ring  36 , a voice coil  38 , and a cup  42 . voice coil  38  is disposed within cup  42  and is held in place by ring  36 . Voice coil  38  preferably comprises aluminum and cup  42  preferably comprises stainless steel, although other materials, including other metals, can be used for voice coil  38  and cup  42  within the scope of the present invention. Ring  36  preferably comprises plastic, nylon, ABS or the like, although other materials may be used within the scope of the present invention. 
     Speaker assembly  30  further includes suspension tubes  40  to operably attach base  44  to panel  32  while allowing panel  32  to vibrate in response to signals received from voice coil  38 . Suspension gasket  35  and suspension tubes  40  preferably comprise rubber, foam rubber, foam plastic, elastomeric material or the like, although other materials may be used within the scope of the present invention. 
     Speaker assembly  30  is bi-directional. The sound energy from a back side  31  of panel  32  is not strongly phase related to that from a front side  33  of panel  32 . Consequently there is the benefit of overall summation of acoustic power in the room, sound energy of uniform frequency distribution, reduced reflective and standing wave effects and with the advantage of superior reproduction of the natural space and ambience in the reproduced sound recordings. 
     While radiation from panel  32  is largely non-directional, the percentage of phase related information increases off axis. For improved focus for the phantom stereo image, placement of the speakers, like pictures, at the usual standing person height, confers the benefit of a moderate off-axis placement for the normally seated listener optimizing the stereo effect. 
     There is a further advantage for a group of listeners compared with conventional speaker reproduction. The intrinsically dispersed nature of panel  32  sound radiation gives it a sound volume which does not obey the inverse square law for distance for an equivalent point source. Because the intensity fall-off with distance is much less than predicted by inverse square law, then consequently for off-center and poorly placed listeners the intensity field for speaker assembly  30  promotes a superior stereo effect compared to conventional speakers. This is because the off-center placed listener does not suffer the doubled problem due to proximity to the nearer speaker, firstly the excessive increase in loudness from the nearer speaker, and then the corresponding decrease in loudness from the further speaker. 
     Turning now to FIGS. 4A and 4B, attachment locations for fixedly attaching speaker assemblies  30  to lid assembly  16  shall be described. In one embodiment shown in FIG. 4A, speaker assemblies  30 , preferably two assemblies  30 , are fixedly attached to back side  22  of lid assembly  16  within recessed area  26 . In one particular embodiment, recessed area  26  has a depth  27  that is preferably between about seven millimeters and about twelve millimeters. The size and depth  27  of recessed area  26  can vary within the scope of the present invention, and depth  27  typically depends in part upon the desired overall thickness of lid assembly  16 . Such a recessed area size permits speaker assemblies  30  to be fully disposed within recessed area  26 . Recessed area  26  then is covered with recessed area cover  28 , such as a plastic or metal grid cover as depicted in FIG.  1 C. Cover  28  operates to protect speaker assembly  30  from harmful contact and, to some extent, from dirt, dust and debris. Recessed area  26  operates as an acoustic chamber to resonate sound waves propagated by speaker assembly  30 , thereby improving audio quality. At least one aspect of the present invention involves the recognition that disposing speaker assemblies  30  within recessed area  26  improves sound quality while further providing some degree of protection to speaker assemblies  30 . 
     Alternatively, speaker assemblies  30  may reside within recessed area  26  by fixedly attaching speaker assemblies  30  to recessed area cover  28 , as shown in FIG.  4 B. Assemblies  30  are disposed within recessed area  26  when cover  28  is attached over recessed area  26 . Similarly, cover  28  operates to enclose recessed area  26  and at least partially protect speaker assemblies  30 . 
     As shown in FIGS. 5A-5C, exemplary attachment mechanisms for attaching speaker assemblies  30  to a mounting surface  52  will be described. Mounting surface  52  preferably comprises the recessed area cover  28  (as shown in FIG. 4B) or a recessed area surface  29  (as shown in FIG.  4 A). It will be appreciated by those skilled in the art that attachment mechanisms described in conjunction with a particular mounting surface also are applicable to other mounting surfaces. 
     Speaker assembly  30  preferably is affixed to mounting surface  52  in a manner which suspends panel  32  above mounting surface  52  a desired distance  60 . Distance  60  preferably is between about 2.5 millimeters and about 12 millimeters. In one particular embodiment, distance  60  is about 2.5 millimeters, although this distance  60  can vary within the scope of the present invention. Suspending panel  32  above mounting surface  52  by distance  60  permits the radiation of acoustic energy from both sides of panel  32  as previously described. 
     Speaker assemblies  30  may be fixedly attached to mounting surface  52  in a variety of manners. For example, epoxy and the like may be used to operably attach cup  42  to mounting surface  52 , thereby attaching speaker assembly  30  to mounting surface  52 . In one preferred embodiment as shown in FIGS. 4A,  4 B and  5 A, four strips  46  are positioned along the periphery of panel  32 . In this manner, panel  32  is attached about its periphery to strips  46 , and strips  46  are in turn attached to mounting surface  52  to affix speaker assembly  30  thereto. Strips  46  may comprise, for example, four rubber strips, four epoxy strips, or some combination of rubber and epoxy strips. Strips  46  also may comprise foam rubber, foam plastic, elastomeric material and the like. The number of strips  46  also may vary within the scope of the present invention. For example, two strips  46  may be operably attached on opposing edges of panel  32  to affix speaker assembly  30  to mounting surface  52 . 
     In lieu of strips  46 , speaker assemblies  30  may be operably attached to mounting surface  52  in the manner depicted in FIGS. 5B or  5 C. FIGS. 5B and 5C depict a plurality of suspension blocks  50  operably attached to panel  32  and mounting surface  52 . In one particular embodiment shown in FIG. 5B, suspension blocks  50  comprise a generally semi-circular-shaped, resilient material, such as rubber, foam rubber, foam plastics and the like. In another embodiment, suspension blocks  50  may comprise generally post-shaped suspension blocks  50 , as shown in FIG. 5C, comprising the same or similar materials. Alternatively, suspension blocks  50  may be square, rectangular, or a wide variety of shapes within the scope of the present invention. Suspension blocks  50  provide support to panel  32  while allowing panel  32  to randomly vibrate to produce exemplary audio output. Blocks  50  preferably are operably attached to surface  52  and panel  32  using epoxy or the like. 
     Positioning of suspension blocks  50  with respect to panel  32  is established to produce desired acoustic output from panel  32 . As shown in FIGS. 6A-6D, exciter package  34 , including outer plastic ring  36 , is shown positioned slightly off-center with respect to panel  32 . Suspension blocks  50  are configured about the periphery of panel  32  in desired locations as shown in FIGS. 6A-6D. Such a configuration facilitates the desired acoustic output and the desired distributed mode sound radiation effects of panel  32 . 
     In conjunction with FIG. 7, an alternative attachment mechanism will be described. In one embodiment, speaker assembly  30  is fixedly attached to recessed area  26 , and more specifically, to recessed area surface  29  using a retaining member  54 . Retaining member  54  may comprise a bolt, a screw, a rivet or the like. As shown in FIG. 7, at least two rivets  56  are used to attach base  44  of speaker assembly  30  to surface  29 . Retaining member  54  fixedly attaches cup  42  to surface  29  in a manner which suspends panel  32  distance  60  from surface  29 . In addition, a plurality of foam pads  58 , and more preferably four foam pads  58 , are positioned generally about the periphery of panel  32 . Foam pads  58  operate to control panel  32  vibration in a similar fashion as the suspension blocks  50  described in FIG.  6 . Such a configuration suspends panel  32  from surface  29  the desired distance to help produce exemplary audio output. Foam pads  58  further provide some measure of protective buffering against the recessed area cover  28  in the event cover  28  is compressed inward. 
     The invention has now been described in detail. However, it will be appreciated that certain changes and modifications may be made. Therefore, the scope and content of this invention are not limited by the foregoing description. Rather, the scope and content are to be defined by the following claims.