GB2508364A

GB2508364A - Wall segment of portable device casing, or protective casing thereof used as flat loudspeaker

Info

Publication number: GB2508364A
Application number: GB201221447A
Authority: GB
Inventors: Richard Prudence
Original assignee: ENTANGLE Ltd
Current assignee: ENTANGLE Ltd
Priority date: 2012-11-28
Filing date: 2012-11-28
Publication date: 2014-06-04
Anticipated expiration: 2032-11-28
Also published as: GB201221447D0; GB2508364B

Abstract

At least one casing wall segment 13c-13g are used as flat loudspeakers by applying a layer of a piezoelectric or electrostatic material to the wall segments (fig 13). The wall segments may be tinned relative to the remainder of the casing so that the wall segments become flexible acoustic diaphragms. Various arrangements of loudspeakers are shown in the drawings, including multiple speakers having respective frequency and /or channel allocations. The channel allocations may be changed in accordance with the orientation of the portable device. Examples of portable devices include but are not limited to, mobile phones, Digital and Analogue audio players and portable computer systems. The use of flat speakers incorporated onto audio membranes enables an effective reduction in device size as well as allowing the device to be reconfigured based on its use.

Description

Audio device housing vJth reconfigurable Sound producing capabilities

s Field of the invention

The present invention relates generally to an audio device with audio amplification provided within the protective housing or through some external casing. The casing in this sense relates to any external device/accessory which may be employed to protect the devices' internal components orexternal surface. An audio device may be considered anything with audio or tone based alarm capabilities: Examples of such devices include but are not limited to, mobile phones, Digital and Analogue audio players and portable computer systems. The present invention also is concerns the integration of acoustic membranes used as the external housing of the acoustic device. Using modern manufacturing processes it is now possible to incorporate a plurality of flat speakers on a single acoustic membrane, thereby offering novel audio signal channel configurations for audio playback. The use of flat speakers incorporated onto audio membranes enables an effective reduction in device size as well as allowing the device to be reconfigured based on its use.

Background

Many devices incorporate loudspeakers for alarm based tone systems and allows for audio playback without the need for earphones or an external headset. In products where such speakers are incorporated it is often the case that they have poor audio quality reproduction. This is a result of poor coupling between the speaker and the surrounding air, thus minimising the achievable frequency spectrum. The output power of these speakers is also significantly constrained due to the need to keep many of these devices small and portable.

Presently, loudspeakers or electroacoustic speakers may be categorised into either direct or indirect speakers, based on their radiation pattern.

Moreover, they are separated into three different groups based on their driving mechanism; moving coil speakers, piezoelectric speakers and s electrostatic speakers. Of these groups, the moving coil is the most mature and is found in almost all commercial products requiring a sound reproduction. However, the moving coil speaker is relatively large and due to its design, makes it difficult to achieve a smaller realisation whilst still maintaining an acceptable frequency response. Current and future devices supporting audio capabilities require speakers to be much smaller and flatter.

Electrostatic speakers are sometimes used in hi-end earphone and speaker products due to their high sensitivity. These speakers operate by placing a conductive membrane between two fixed porous electrodes to is form a capacitor. Sound is then produced by the electrostatic force by applying a changing DC bias to the membrane.

Conventional electrostatic designs make use of rigid metallic electrodes that offer the ability to be bent or shaped based on their application. The requirement however for metal electrodes adds additional weight and expense to the speaker design. Furthermore, the speaker driving circuits require the use of high voltage and low current transformers to effectively convert standard digital or analogue audio signals. To deliver these high voltages, custom boost converters or transformers with a large numbers of turns are required; reducing the scale of these drivers is still a young area of research. These speakers have been proven effective but lead to complex designs that are presently not suitable for portable audio devices.

The piezoelectric speaker vibrates a membrane to produce sounds based on the piezoelectric effect of a piezoelectric material (i.e. on the application of an electric field, the material is deformed). These piezoelectric speakers have a compressed and small structure making them ideal for lUture audio devices.

Some recent advances in piezoelectric speakers now make it possible to create flat speakers as thin as a standard piece of paper. An example of such a process is in printable electronics. The latter resulting in piezoelectric cellulose EAFap, which generate sound based on s electronically stimulated organic polymers. Furthermore, advances made in sensory manufacture (as the result of capacitive touchscreen development), allows these piezoelectric speakers to be easily incorporated into materials such as glass and plastic.

Thus far, prior art that makes use of piezoelectric flat panel speakers io include US 7664278; which incorporate the technology to maximise the voicing areas for the use in wireless communication apparatus. Such a proposed arrangement allows the flat speaker to be installed behind the screen on the portable device, or made of any transparent material so as to cover and protect the devices buttons and screen.

is An extension to these concepts pertains to a method of mounting conventional flat panel speakers to the housing of a portable device. An example of existing assembly method is covered in US 7792319.

The prior art examined solves the problem attributed to maximising the voicing area of the speaker in mobile communication devices by taking advantage of the largest flattest surface, namely the LCD or LED display of the device. All of the above designs concern the method by which the speaker is installed into the device, but have made little effort to reduce the overall complexity of the device. Furthermore, as a majority of these designs require the use of a piezoelectric drivers or a vibrating element, they offer little internal space saving advantages over traditional moving coil speakers. Moreover, little development has been seen in speaker design such that they may be installed into mobile communication or audio devices that do not have a large fiat surface such as a display screen.

Statements of invention

In view of the above, it is an object of the present invention to provide a structure and method of supplying an apparatus for use with an s audio device to deliver audible sound and overcome some of the known disadvantages of conventional loudspeakers used in portable audio devices. This presented structure and method proposes an audio device housing that incorporates at least one acoustic membrane comprising of a flexible diaphragm region on which a layer of piezoelectric or electrostatic io material is embedded. Wherein at least one acoustic membrane is arranged toform part of the at least one wall of the apparatus housing.

According to the first aspect of the present invention, there is an apparatus providing a structure for mounting an acoustic membrane, is incorporating a flat panel speaker, onto the housing body of the audio device. The embedded flat speaker emits sound waves by vibrating the diaphragm region attached to the housing assembly, the structure includes: one or more rigid elements which are bonded with the rear of an acoustic membrane. This is used to constrain movement and deformation to specified directions as well as to correctly positioning the membrane within the apparatus housing assembly; wherein at least one wall of the apparatus includes a substantially rigid element; wherein the acoustic membrane is positioned relative to the external cavities in the apparatus housing assembly also shaped to contain the audio device; a rigid element may be bent to form shapes not limited to concave or convex angles; wherein the shape of the rigid element is designed to maximise the functional surface area of the membrane or improve the ergonomics of the apparatus; wherein a rigid element may be made of one or more parts; a rigid element may have notches, extrusions or tensioning to securely bond or clip into the designated cavities in the apparatus; wherein the apparatus assembly possesses cavities to receive and s bond with the rigid element; moreover, a plurality of rigid elements may be used to bond a single flexible membrane to multiple sub-assemblies of the apparatus; io In the foregoing first aspect, preferable configurations of the apparatus structure are exemplified in the provided illustrations described in FIG. 2 and 3A to 3D, these configurations include: at least one acoustic membrane that connects a plurality of subassemblies as part of the structure of the apparatus assembly.

is An acoustic membrane containing at least one ora plurality of diaphragms; wherein the dimensions of the acoustic membrane do not substantially correspond to the dimensions of the audio device; wherein the dimensions of the speaker diaphragm do not substantially correspond to the dimensions of the acoustic membrane or the audio device.

an acoustic membrane may preferably extend beyond the dimensions of the audio device in the vertical and horizontal directions; wherein the acoustic membrane that adjoins a plurality of subassemblies may form part of two non-parallel walls of the apparatus; Furthermore, a preferable configuration is one wherein the audio device has a display unit to display characters and image information and the acoustic membrane is made of a transparent material and could serve to protect the audio device's display screen.

According to the second aspect of the present invention, there is provided an acoustic membrane attached to the housing assembly of an audio device, making up one ora plurality of flat panel speakers that emit sound waves by induced vibrations, The diaphragm including: s at least one acoustic membrane consists of one ora plurality of flat panel speakers.

wherein each of the flat speakers is designed to operate over a different frequency range and/or at a different operational volume.

wherein each flat panel speaker is connected to the speaker driver io by a separate audio signal channel and wherein the audio signal channels are reconfigurable.

an acoustic membrane is of variable cross-sectional thickness to preferentially transmit vibrational energy to predetermined regions of the acoustic membrane, where said regions hereon are referred to as s diaphragms.

an acoustic membrane of dimensions that does not necessarily correspond to the dimensions of the audio device.

wherein the dimensions of the flat panel speakers to not substantially correspond to the dimensions of the audio device.

According to the third aspect of the present invention, the control of the flat panel speakers embedded onto the acoustic membrane and used to produce audible sounds may be dynamically reconfigured using a structure that includes: a sensor in communication with the speaker driver allowing the audio signal channels to be reconfigured based on the output signal from said sensor.

wherein the sensor is adapted to monitor the orientation of the apparatus and/or audio device.

a housing comprising of a plurality of walls and a single acoustic membrane.

wherein the audio signal channels could be adapted to also function as wireless transceivers or any other piece of sensory equipment.

Examples include, but are not limited to, microphones, wireless antennas s for signal and power transmission.

the audio signal channels are adapted to be configured in a mixed serial parallel configuration to generate a desired response.

io According to the fourth aspect of the present invention, a protective layer may be applied to the acoustic membrane to prevent damage to the embedded flat speaker, the protective layer possessing the properties: a material to prevent short circuiting or altering the performance of the embedded flat speaker; is wherein the material is preferably nonconductive and possesses properties such as flexibility; a gripped texture to aid in grasping of the apparatus, using a multitude of materials or varying cross-sectional thickness; aesthetic characteristics concerning shaped indentations and extrusions and colour variation; In the forgoing aspects the flat speaker is attached to the audio device housing assembly in which the acoustic membrane may be moulded or shaped to adhere to the concave and convex portions of the housing assembly as part of the ergonomic or aesthetic design of the housing.

Also, a preferable mode of configuration is one wherein, in a specified portion of the audio device, the piezoelectric drivers are positioned near the connection points to the array of flat speakers embedded in the diaphragms that make up the housing of the loudspeaker transducer or audio device. Alternatively, each flat speaker may have a separate speaker driver thereby preventing connection points from being routed to a single point on the housing.

Such embodiments within an apparatus or audio device requiring loudspeaker lUnctionality yields numerous advantages over devices using miniature moving coil speakers and much prior art utilising flat speaker technology.

Accordingly, by embedding piezoelectric or electrostatic speakers into the housing or casing of an audio device the internal space occupied io by a traditional moving coil speaker may be used to serve additional functions. Examples of additional functionality may include the use of additional sensory equipment, added computational power, and general circuit board space.

Furthermore, as the speaker is no longer part of the internals of the is device, speaker holes on the exterior housing are no longer needed. By avoiding the use of internal speakers audio transmitted through the flat loudspeaker is less directional and less prone to distortion.

Moreover, by having one or a plurality of flat speakers as part of the device housing the audio signal channels of the device may be easily reconfigured to adjust for the orientation of the portable audio device. This may be made possible by using the signals from an internal sensor within the device or apparatus. Based on the readings from the sensor the audio signal channels may be reconfigured to deliver the best audio response.

This orientation dependant configuration makes the system ideal for portable media devices such as smart phones and tablets, where already the orientation of screen content automatically adjusts to the device orientation. No prior commercial device has delivered the capability to reconfigure multiple audio signal channels in the same manner.

Dynamically reconfiguring the audio signal channels to accommodate for the device's orientation is of great benefit to portable device designers and media consumers.

tot figures Embodiments of the present invention will now be described by way of example only with reference to the following figures: s Figure 1 is an exploded perspective view of a device case assembly incorporating a device with audio producing capabilities in accordance with the present invention.

Figure 2 is an isotropic-assembly-view illustrating the interconnection between various assemblies in a particular configuration.

io Figures 3 a-b illustrates possible configurations of the present invention aligned parallel to the longest dimension of the audio device.

Figures 3 b-c illustrate possible configurations of the present invention aligned parallel to the shortest dimension of the audio device.

Figure 4 is an exploded view displaying one possible configuration of the is acoustic screen part incorporating a single acoustic membrane.

Figure 5 is an exploded view of the acoustic screen protector incorporating a plurality of acoustic membranes.

Figure 6 is a top down view of the illustrating the use of a plurality flat speakers incorporated into a single acoustic membrane.

Figure 7 is an exploded perspective view of an illustrative configuration with an audio device incorporated with acoustic membrane as exterior housing.

Figure 8 is an isotropic view of the assembly of an audio device incorporating a protective case with a plurality of acoustic membranes making the outward facing surfaces of the protective casing.

Figure 9 is an isotropic view of an audio device incorporating a plurality of acoustic membranes as the exterior housing of the device.

Figure 10 is an isotropic view of an audio device housing constructed from a molded acoustic membrane incorporating a plurality of flat panel speakers.

Figure 11 is a cross-sectional view of the acoustic membrane displaying clearly different layers and variable factors of the regions forming a -10-diaphragm.

Figure 12 is a top dawn view of an acoustic membrane and flat speaker assembly combining multiple assemblies.

Figure 1 3a -b is an electrical schematic illustrating the parallel and serial s configurations of flat speakers respectively across a plurality of diaphragm regions.

Figure 14 is a block diagram illustrating the functional blocks of the audio device, and audio signal transducer in accordance to the embodiment of the present invention.

io Specific description

The present invention disclosed herein relates to the use of an acoustic membrane incorporating modern hat speaker technologies to replace the demand for conventional loudspeakers in audio devices.

is By embedding the acoustic membrane into the protective housing or casing for an audio device, this reduces the need for a loudspeaker to be held internally within the device. The exclusion of this component from the device's internals yields a number of advantages. Firstly, smaller portable audio devices such as cellular phones and tablets incorporate a loudspeaker for audio playback and teleconferencing. These applications demand a loudspeaker that supports a wide range of volumes and offer a wide bandwidth of audible frequencies. For both of these requirements to be met, the speaker contained within the device is frequently placed in obscure positions, including the side face and back of the device.

Moreover, the outlets for the sound produced by the loudspeaker almost always offer a smaller surface area than that of the diaphragm present on the loudspeaker. These aesthetic outlets not only lower the volume of the sound leaving the device, but also add additional levels of distortion to the sound, harming audio quality. Furthermore, the outlets result in the transmitted sounds becoming more directional; thereby resulting in different perceived volume levels depending on the listeners' location with respect to the device.

Lastly, removing the loudspeaker from within the audio device yields additional space that may belier be used for the inclusion of additional components.

The term audio device is intended to encompass smaller devices, such as handheld portable devices not limited to the digital MP3 players, mobile phones, media player, tablet PCs, CD Walkman and players that incorporate other forms of digital and analogue methods of music storage.

The term further extends to larger audio devices such as Hi-Fi systems, io and in car sound systems, which deliver much higher levels of sound amplification and better sound quality. In reference to the aforementioned terms included under the term audio device the term is additionally intended to encompass the ability to produce sounds without the means of external loudspeakers being attached.

In the following description, the functional components embodied within the present invention will be explained in greater detail with reference to the appropriate figures.

Fora slim-line audio signal transducer 15, as shown in FIG.1, for use with an existing audio device 2, the various internal configurations and capabilities will be detailed. The outer casing that is used to protect the audio device 2 may have an upper cover Ito protect the upper portion of the audio device, and to securely fasted the entire assembly of 15 to the audio device housing. The interconnection between I and 15 may be facilitated ideally by a clipping mechanism, thereby allowing the audio device to be removed. Alternative methods of connecting the upper and lower portion may be achieved through methods not limited to adhesives, magnets, tensioning (elastic and non-elastic) and friction.

The audio amplification device 15 assembly incorporates numerous components to enhance the abilities of the existing audio device.

The upper casing member 3 may be formed of any suitable materials -12-including plastic, wood, glass, ceramics, or other suitable materials, or any combination of these materials. Of these materials light-weight low density materials such as polycarbonate, ABS plastic and aluminium are preferred.

The upper casing membrane may be produced through the processes of s injection moulding, or by combining a plurality of interconnected parts produced from different processes.

The upper casing member 3 should be shaped to aid in protection of the audio device without reducing functionality of the device. Forthis reason, suitable extrusions are made to allow for the audio signal transducer 15 to io connect or dock with the audio device 2. These extrusions include 4, which allow the device connector 7 to extrude from 3 to allow for a flush connection with the device.

Examples of edsting standardised digital audio device connectors 7found in commercial products include mini and micro and standard USB 2.0 and is 3.0 ports, Apple 32-pin connectors and expansion slots (such as SD and micro-SD card slots). Other custom connectors are routinely used to maintain back compatibility with legacy hardware made by some manufacturers.

Alternatively, the need for a digital device connector 7 by be avoided if the use of an analogue audio signal is preferred. In this scenario a standard audio jack may be used to transmit the audio signal from the audio device 2 to the audio signal transducer 15.

Further extrusions, which must be accommodated for include, outward facing cavities S to accommodate for outward facing sensors within the audio device. Examples of outward facing device sensors include cameras, light sensors, heat sensors, microphones and internal speakers.

Internally, the audio signal transducer includes electronic components 6 to allow for amplification and improvement of the digital or analogue signal produced from the audio device 2. These electronic circuit boards within the device may offer additional digital and analogue outward connections 8 for transmitting the audio signal into other devices. For the purpose of -13-allowing for portability, the audio amplification device may use a power source 9, such as a wall power source, Li-Ion Battery, or standard AA or AAA batteries through a connector 10. Alternatively, the audio signal transducer may utilise the power source supplied from the host audio s device through a dedicated power connection or through standard pin-outs in digital or analogue connectors.

Following the assembly of the internal electronics of the audio signal transducer, a rigid frame-shaped gasket member 11 must be fused with the acoustic membrane 13, which is used to transmit the amplified version of io the input sound signal. The gasket member allows the acoustic membrane to be correctly positioned with respect to the device, and connects the acoustic membrane securely to the internals of the casing assembly.

The gasket member 12 and the membrane 13 may be bonded using any form of adhesive, such as, but not limited to double-faced adhesive tape.

is Next, the cover member 14 is attached of the back face of the audio amplification device. This ensures the membrane and gasket member are properly fixed within the assembly of 15, and may incorporate other aesthetic qualities to improve the exterior look of the device.

Leading on from FIG.1, FIG.2 illustrates the use of 15 and 2 with the addition of a flat panel speaker 17 to aid in the protection of the front face portion of the audio device 2, where a screen as well as user controls are frequently located. This flat panel speaker 17 is attached to the signal transducer assembly 15 through ajoining member 16.

The joining member 16 transmits the analogue ordigital signals of the audio present on the audio device 2 from the signal transducer assembly l5to the flat panel speaker assembly 17. The joining member 16 may be flexible, rigid or a combination thereof, depending on design requirements.

In the case of a flexible joining member 16, the materials or parts may include, but are not limited to, leather, plastic, latex, ribbon cable, an additional flat speaker part that may seamlessly connect 15 and 17. In such a case there would be a single flat speaker that would form part of the -14-casing assembly as well as the flat panel assembly. Alternatively the joining member 16 may be composed of rigid parts and may be designed as a one, two or three axel hinge. In this case the joining member 16 could be designed to allow movement and rotation of the flat panel speaker 17 in s multiple degrees of freedom. Assemblies can be detachable from the joining member 16 for independent use or replacement. The methods by which the assemblies may be conjoined include, but are not limited to, adhesives, magnets, tensioning (elastic and non-elastic), friction and through any standard connector.

The interconnection between the audio device 2, flat panel speaker 17, connecting member 16 and casing audio transducer assembly 15, may be achieved with numerous possible combinations. For the purposes of illustration the most common combinations have been fully explained in is FIG.3A through 3D.

FIG.3A illustrates the identical scenario as in assembly FIG.2 in which the flat panel speaker 17 is attached via joining member 16a to the bottom plane of the audio device in a vertical configuration. A similar configuration is given in FIG.3B with joining member 16b attached to the top-side-plane of the audio device.

FIG.3C illustrates a configuration with the flat panel speaker attached to the left-side-plane via the joining member 16c. It should be noted that the equivalent configuration is achievable on the right-side-plane of the audio device using the same joining member 16c.

FIG.3D illustrates the two possible permutations of FIG.3C in combination using two flat panel speakers 17a, 17b and two joining members 16d and 16e. This same principle may be applied in the vertical direction as well by combining the initial configurations of FIG.3A and FIG.3B. An extension to all aforementioned configurations pertains to the interconnection of multiple joining members and flat speaker assemblies. In this manner these assemblies may be attached in a mixed serial or parallel configuration -15-either predetermined or dynamically reconfigurable.

Lastly, based on the descriptions of FIG.3A to FIG.3D, the positioning of the flat panel speaker 17 to one side of the audio signal transducer 15 does not prevent the joining member l6ltom being connected to a plurality of s planes on the audio device. Common planes include the bottom plane and the plane perpendicular to the axis of movement for the joining member 16.

The flat panel speaker 17 offers two alternative assemblies depending on the desired level of complexity of the audio signal transducer 15. FIG.4 io illustrates the first combination using a single acoustic membrane. FIG.5 illustrates an alternative assembly incorporating more than one acoustic membrane.

As illustrated in FIG.4, flat panel configuration A, the rigid panel member 19 offers structural support to house the gasket member 12 and flexible is membrane 13 in a defined shape that resembles the shape of the upper portion of the audio device. Lastly, a frame member 18 is used to improve the aesthetics of the flat panel speaker assembly and securely enclose the edges of the membrane and gasket member.

Moreover, FIG.5 displays the full assembly of the flat panel speakerwith multiple acoustic membranes 13a, 13b. Combining membranes 13a and 13b into a single flexible membrane delivers an alternative scenario in which a single folded membrane covering both top and bottom planes of the assembly is used. In order to securely fix position the membranes, gasket members 12a and 12b, as well as a central rigid panel member 20 is required. Central rigid panel member 20 is shaped to support the two gasket members 12a and 12b and reflect the vibrations generated from the on acoustic membrane. Lastly, two flat frame members ISa, lSb are required to securely enclose the edges of the gasket member and membrane to 20. -16-

Atop down view of the gasket member 12 and the acoustic membrane 13 is given in more detail in FIG.6. In this illustration the entire acoustic membrane is designed to act as a diaphragm, whereby multiple flat panel speakers are embedded onto it. In this sketch, three separate flat panel speakers 21a, 21b and 21c are visible. These three cases demonstrate that flat panel speakers incorporated into the diaphragm region do not have to have identical dimensions, or occupy the same functional surface area.

Furthermore, as illustrated by 21c the flat speakers do not have to be limited to a rectangular shape, and are furthermore not limited to straight io edges or corners. This type of configuration means that not all flat speakers present on a single diaphragm region of the acoustic membrane will be given the same input audio signal or occupy the same audio channel.

Spaces between flat panel speakers may be made even more fledble, thereby allowing the membrane to bend significantly between the is designated flat panel speaker regions.

Referring now to FIG.7, this illustrates an exploded view of a portable device 22 with an embedded flat speakerwithin the housing assembly. This assembly divides the components into an upper portion, and lower portion respectively. The upper portion of the device includes components such as display 25; touch screen 26 and user controls 27. The lower portion, which may sometimes be referred to as the housing assembly 24, may include a housing 32, printed circuit boards 28 and electrical components that may be mounted to the housing. The housing 32 is referred to as the body that encapsulates the internal components of the housing assembly 24.

The exploded perspective displayed in FIG.7 exemplifies the scenario in which the acoustic membrane 13 makes up the bottom plane of the housing assembly, and is thus part of the housing assembly.

As in previous figures, the acoustic membrane 13 that incorporates the embedded flat speakers is fixed to the housing by a gasket member 33. In this illustration the gasket member is shown to have additional structural support so as to provide support to more central regions of the membrane. -17-

Component 35, is a shaped frame member to best fit the geometry of the audio device in question.

Additionally, the housing assembly may include a dividing section 31, to prevent the electrical components coming in direct contact with the gasket s member 33 or membrane 13.

Extending the scope of FIG.7 is FIG.8, which demonstrates the possibility of having multiple acoustic membranes on a plurality of sides of an audio signal transducer 15. Overall all sides or faces on a casing assembly may io have an acoustic membrane incorporating a multitude of different flat panel speakers within different diaphragm regions.

As illustrated, 15 may have all sides covered by membranes 13d-13f, as well as the bottom side consisting of a membrane 13c. It should be noted that the two possible configurations of the membrane assemblies may be is viewed conceptually as the membrane to cover! protect the upper portion of the audio device 2.

FIG.9 extends the scenario of FIG.8 for an audio device 22 incorporating multiple faces of the housing assembly as speakers in a similar configuration to that illustrated in FIGS. Again, acoustic membranes 13c- 13f may be appropriately shaped and fixed to a moulded housing to protect the internal components of the device.

The advantages of having such a housing enables for more interaction between the sound source, the design of the audio player and the interaction with the listener. Lastly, no additional space is required to provide a much larger audio source, as this is effectively the housing for the device.

Notwithstanding membranes produced separately and then fixed to a housing member, the alternative option is to embed the membrane containing the flat speaker into the manufacture of the housing member. In -18-the event that non-conductive materials such as plastics and glass are used to produce the housing member, the acoustic membranes may be incorporated to provide adequate structural integrity and provide enough flexibility for the transmittance of sound into the surroundings. This concept s is encapsulated in FIG.1O, an isometric view ofa shaped membrane. The acoustic membrane indicated bends around an identified horizontal axis 36.

Including more bends along other axes may allow a membrane to be shaped to best accommodate the internal components of the audio device 22.

io In order for such bends to be made possible plastics and thermally alterable non-conductive materials would have to be used. In this manner, they may be bent and retain their shape. Alternatively, there may be cases as discussed previously that a membrane made from a flexible material is also desirable.

A cross-sectional view of an acoustic membrane 13 is illustrated in FIG.11.

This diagram presents some variable factors of the acoustic membrane's parts that alter the sound characteristics and structural integrity of the housing member. These factors include the thicknesses of the acoustic membranes 45 and 44, the positions of these acoustic membranes acting as diaphragms within the region 38 and other layers of different materials included in the figure.

For an acoustic membrane of thickness 40 a flat speaker 21 may be inset into the diaphragm region 38. By adjusting the insets 41 and 42 the appropriate depth of the flat speaker may be selected with respect to either the bottom or top surface plane of the membrane. Such adjustments are important when considering the directionality of the sound produced by the flat speaker. Consider the scenario when distance 41 is set significantly less than 42, the greatest direction of motion of the diaphragm region is in the direction of 42. Altering such measurements is additionally important when considering manufacturing processes to produce the diaphragm -19-region.

Further factors that need to be considered when designing the housing assembly and diaphragm arrangement of the audio signal transducer is the thickness 39 and surface area governed by distance 38. The frequency s range and maximum amplitude of the speaker may be adjusted by altering these two properties. As such, by reducing the thickness 39, the flat panel speaker will possess more vibrational potential. Furthermore, by increasing the surface area governed by 38, there is an increase in the amount of air that may be displaced.

io The total thickness of the flat panel speaker 21, may be determined by the thickness of the piezoelectric or electro-static layers 43 printed onto 44.

Alternatively, due to further advances in sensory manufacture, piezoelectric or electro-static layers 43 may be combined into 44 using a single process.

Lastly, an additional factor that adds thickness to the acoustic membrane's is diaphragm region is the protective coating 37 added to the surface of the membrane and flat panel speaker.

The protective layer 37 that may coat the membrane serves to prevent short circuiting ordamage to the piezoelectric or elector-static circuits that produce the flat panel speaker. It further aids to protect the acoustic membrane material 45 as well as the acting diaphragm 44. Furthermore, 37 may be considered part of the aesthetics of the device. 37 may offer a textured surface to aid in grasping the audio device, or coating to aid in cleaning the device.

The dimensions of the acoustic membrane 13 and flat panel speakers are not constrained to the dimensions of the audio device 15/22, or single assembly. An exemplary illustration of this is presented in FIG.12, where a single membrane extends to combine the audio signal transducer 15, joining member 16, and protector assembly 17.

This concept may further be applied to the configurations outlined in the aforementioned FIG.3A to 3C.

-20 -In all such scenarios the membrane 13 must be made of a flexible or bendable material allowing it to undergo reasonable amounts of bending and torsion around the central axis 46 that passes through the centre of the joining member 16, depending on the presented configuration.

s Lastly, flat panels speakers 21a and 21b may combined into a singular larger speaker either by extending the diaphragm and speaker area of 21a to encapsulate 21 b or by configuring the audio channels in a parallel configuration, or serial configuration requiring software or driver control.

io Embedding a plurality of flat panel speakers into multiple membranes offers the advantage of numerous channel combinations. Such speaker configurations may be exemplified by the scenarios illustrated in FIG.13A and FIG.13B. Firstly, the case examined in FIG.13A is that of two acoustic membranes 13a and 13b each with different numbers of flat panel s speakers. Membrane 13b contains flat panel speakers 21b and 21c, whereas 13a contains only 21a. All speakers examined in this example are in a parallel configuration from a central piezoelectric driver array 47. The ability to organize speakers in a parallel configuration allows the output resistance of the speaker to be more finely adjusted based on the know characteristics of the flat panel speakers.

FIG.13B examines the scenario inwhich flat panel speakers 2lato 21c are configured over membranes 13a and 13b in a serial configuration. By configuring the piezoelectric driver 47 array to output on multiple speakers in serial, each flat panel speaker may be attached to a separate audio channel. In this manner more advanced systems such as 5.1 and 7.1 surround may be achieved in a relatively small space within the housing of the audio device.

The separated audio channel configurations are not limited to the examined parallel and serial scenarios in FIG.13A and FIG.13B respectively. Channel combinations from the output of the audio device may include both serial and parallel configurations. Furthermore, the channels may be -21 -reconfigurable through the use of hardware or software solutions. This ability to dynamically configure the output audio channels means it may be optimally changed to achieve belier audio quality based on the surroundings of the user. Examples of such adjustments include altering s the orientation of the portable device. Using modern sensory equipment 56, the orientation of the audio device may be accurately determined through the use of sensors, not limited to, accelerometers and gyroscopes.

Based on this sensory equipment the Left and Right channels of the device may be reconfigured to match the orientation of the audio device.

The functional configurations of block diagram FIG.14, examine the internal connections and processes that describe the embodiment of the present invention. The block diagram encapsulates the audio device 2 and audio signal transducer 15 separately, but describes the elements that would is need to be removed to create a single device 22 according to the embodiment of the present invention. Directional arrows indicate the direction of signal transfer and lines indicate a direct connection.

Within 2, all audio data used to generate music on the audio device must be retrieved from the device memory block 57. Examples of memory storage include analogue and digital memory, not limited to, tape cases, CD, hard disk and flash memory.

The Central Processing Unit (CPU) 53, or a like, executes various programs stored internally, or read from the Device Memory 57. This section controls each component to perform the appropriate communication control processing, displaying and operating forms of control for the audio device. This is achieved by using various registers and flags stored within the memory section of the audio device.

The audio device 2 may have wireless communication capabilities, such as Wifi, 3G or GPS stored within 54, either to receive or transmit audio and video data.

The Internal and External Sensors block 56 may include devices, not -22 -limited to, light sensitive diodes, microphones, heat sensors and visual camera, gyroscopes, accelerometers and magnetometer equipment to add to the functionality and controllability of the user device.

For obtaining information concerning device orientation it is preferable that s sensors such as gyroscopes or accelerometers are used. The output signal from these sensors may be fed into the signal transducer 15 if the sensor is already present within the audio device. If the sensors is not already present, the signal, ordigital information thereof may be transmitted to 15 through the use of the Digital I/O 52 connection. Alternatively, the sensors io may be part of 15 within the DSP block 51.

Using the sensor signal the configuration of the flat panel speakers part of the acoustic membrane and device housing may reconfigured correctly based on the orientation. Forexarnple if 5.1 audio channels are supported by the device, the speakers may be assigned appropriately based on the is known orientation of the device.

The Digital I/O (input-output) 52 between the two devices 2 and 15 may be used to transmit signals in common communication protocols between the two devices. The physical connection between the to devices may be facilitated through a digital connector 7 as described in the aforementioned figures. The audio data obtained from 57 may be directly transmitted to the Digital Signal Processing (DSP) block 51 to be altered to produce the optimal sound on 15. Furthermore 51 will then take the processed data and convert it into an analogue signal through 49. The analogue signal can then be amplified in block 48 before being transmitted through the flat panel speaker and diaphragm region. This channel management is performed by the speaker driver array 47 and DSP 51 blocks before being transmitted as sound from the desired flat speaker configuration 13.

The function performed by the speaker driver array 47 is comparable to that of a multiplexer in digital and analogue electronics. Therefore, the speaker driver array assigns a given audio signal channel to a desired set of flat panel speakers, represented by 13. As a design consideration a -23 -plurality of speaker driver arrays may exist as part of the circuitry in the audio signal transducer 15. As such the number of speaker drivers is not necessarily representative of the number flat panel speakers.

Lastly, as the audio signal transducer device 15 may be considered a s parasitic device to enhance the audio capabilities of device 2, it is likely that 2 may contain its own sound production capabilities. The functional blocks within 2 that display sound production capabilities are the audio controller and Analogue L'O 50. More specifically, the Analogue L'O may be considered a headphone jack for use with standard amplifier systems io requiring analogue input. Furthermore, audio signal transducer 15 may also amplify the analogue signal produced by 2 Alternatively the Analogue VO may be used to transmit the audio signal channels from the audio device 2 to the audio transducer davice 15. This may limit the number of audio signal channels supported by the transducer is but provides an option for simplifying the complexity of the transducer device 15. This direct connection may be made possible using a standardised 2 or three channel audio jack cable to transmit mono andlor stereo and microphone connections from the audio device 2 into 15.

Designing the audio transducer device 15 for analogue input reduces the complexity of described block diagram depicted in FlG.14 as blocks 52, 51 are no longer required. Moreover, Digital analogue converter block 49 no longer needs to perform conversions and rather reduces noise signals in the input signal before amplification by 48.

Preferably interconnection between the two devices is done using digital signals. Digital connections offer the possibility for greater degrees of audio channel reconfiguration and improved audio quality. In the case that video media is supported by the portable audio device a digital connection will allow Dolby Digital 5.1 and 7.1 audio channels to be supported by the audio transducer device 15. This offers a much greater advantage over limiting support to stereo channels of left and right respectively.

-24 -In FIG.14, in the scenario that both device 2 and 15 were to be consolidated into a single device 22, repeated functional blocks may be removed without altering the functionality or performance of the device.

Repeated numerals of note include the Digital VO 52, Audio controller 55 s and Analogue VO 50.

Within such a device 22, the main benefits of the present invention compliment some features of existing technology. For example the images and text on a screen display on some devices may be rotated based on the output signal from a gyroscope sensor. In a similar way the ability for the io audio channels to be reconfigured dynamically based on the orientation of the device means the audio and video both match the general orientation of the device. The information about the devices orientation may come from the same or different sensor.

-25 -In the foregoing it should be understood that: a) the word "comprising" does not exclude other elements or acts that those listed in the given claim; s b) the word "a" or "an" preceding an element does not exclude the presence or plurality or such elements.

c) any reference signs in the claims do dot limit their scope d) Several "means" may be represented by the same item or hardware or software implemented structure or function; e) any of the disclosed elements may be comprised or hardware portions (e.g. including discrete and integrated electronic circuitry), software portions (e.g. computer programming), and any combination thereof; f) hardware portions may be comprised of one or both is analogue and digital portions; g) any of the disclosed devices or portions thereof may be combined together or separated into further portions unless specifically stated otherwise; No specific sequence of acts or steps is intended to be required unless specifically indicated.

Claims

-26 -Claims 1. An apparatus connectable to a portable audio device for converting an audio signal from the audio device into an audible sound, the apparatus S comprising: a housing comprising at least one wall; at least one acoustic membrane comprising a flexible diaphragm region and a layer ofpiezoelectric orelectro static material, wherein at least one acoustic membrane is arranged to form part of at least io one wall of the housing; a terminal for connecting a signal output from the audio device to the apparatus; and a speaker driver in communication with the audio device terminals and the flat speaker embedded into the acoustic membrane wherein, is when in use, the flexible diaphragm region of the acoustic membrane generates audible sounds corresponding to output signals from the audio device.
2. The apparatus of claim 1, wherein at least one acoustic membrane comprises of at least one flat panel speaker.
3. The apparatus of claim 2, wherein at least one acoustic membrane comprises of a plurality of flat panel speakers.
4. The apparatus of claim 3, wherein each one of the plurality of flat panel speakers is designed to operate at a different frequency range and! or at a different operational volume.
5. The apparatus of claims 3 or4, wherein each flat panel speaker is connected to the speaker driver by a separate audio signal channel and wherein the audio signal channels are reconfigurable.

-27 -
6. The apparatus of claim 5, l1rther comprising a sensor in communication with the speaker driver whereby the audio signal channels are reconfigured with respect to an output from the sensor.
7. The apparatus of claim 6, wherein the sensor is adapted to monitor the orientation of the apparatus.
8. The apparatus of any one of the preceding claims, wherein at least io one wall of the housing includes a substantially rigid element and the flexible acoustic membrane is bonded to the rigid element.
9. The apparatus of any one of the preceding claims, wherein the housing comprises a plurality of walls and a single flexible acoustic is membrane.
10. The apparatus of claim 9, wherein the flexible acoustic membrane is of variable cross-sectional thickness to preferentially transmit vibrational energy to predetermined regions of the membrane.
11. The apparatus of claims 9 or 10, wherein the dimensions of the acoustic membrane do not substantially correspond to the dimensions of the audio device.
12. The apparatus of any one of claims 3 to 10, wherein the dimensions of the flat panel speakers do not substantially correspond to the dimensions of the audio device or the acoustic membrane.
13. The apparatus of claim 5, wherein the audio signal channels are adapted to also function as a wireless transceiver and/or sensor.-28 -
14. The apparatus of claim 5, wherein the audio signal channels are adapted to be configured in a mixed serial or parallel configuration to generate a desired response.s
15. The apparatus of any one of the preceding claims, further comprising an outer protective layer.
16. The apparatus of any one of the preceding claims, wherein the housing is conformed to receive and protect the hand-held audio device.
17. An apparatus connectable to a portable audio device substantially as described hereinbefore with reference to figures ito 3 and 8.
18. A portable audio device substantially as described hereinbefore with is reference to figures 7 and 9.
19. A portable audio device comprising: a housing having at least one wall; at least one acoustic membrane comprising a Ilexible diaphragm region and a layer of piezoelectric or electrostatic material, wherein the at least one acoustic membrane is arranged to form pad of the at least one wall of the housing; a processing unit operable to generate an audio signal; and a speaker driver in communication with the processing unit and the flat speaker of the acoustic membrane wherein, when in use, the flexible diaphragm region of the acoustic membrane generates audible sounds corresponding to audio signals at the signal output of the audio device.
20. A portable audio device according to claim 19, wherein at least one acoustic membrane comprises at least one flat panel speaker.-29 -
21. A portable audio device according to claim 20, wherein at least one acoustic membrane comprises a plurality of flat panel speakers.s
22. A portable audio device according to claim 21, wherein each one of the plurality of flat panel speakers is designed to operate at a different frequency range and! orat a different operational volume.
23. A portable audio device according to claims 20 or 21, wherein each flat panel speaker is connected to the speaker driver by a separate audio signal channel and wherein the audio signal channels are reconfigurable.
24. A portable audio device according to claim 23, further comprising a sensor in communication with the speaker driver whereby the audio signal is channels are reconfigured with respect to an output from the sensor.
25. A portable audio device according to claim 24, wherein the sensor is adapted to monitor the orientation of the apparatus.
26. The apparatus of any one of the preceding claims, wherein at least one wall of the audio device housing includes a substantially rigid element and the flexible acoustic membrane is bonded to the rigid element.
27. The apparatus of any one of the preceding claims, wherein the audio device housing comprises a plurality of walls and a single flexible acoustic membrane.
28. A portable audio device according to claim 27, wherein the flexible acoustic membrane is of variable cross-sectional thickness to preferentially transmit vibrational energy to predetermined regions of the acoustic membrane.-30 -
29. A portable audio device according to claim 24, wherein the audio signal channels are adapted to also function as a wireless transceiver or sensor.
30. A portable audio device according to claim 24, wherein the audio signal channels are adapted to be configured in a mixed serial or parallel configuration to generate a desired response.
31. A portable audio device according to any of the preceding claims, further comprising an outer protective layer.
32. A portable audio device according to claim 19, wherein the portable audio device is a hand-held audio device.