Mobile device

A mobile device is disclosed. A mobile device comprises a display, a battery disposed on the back side of the display, and a film speaker disposed on the back side of the battery.

FIELD

Embodiments of the present disclosure relate to a mobile device, and more particularly relate to a mobile device with a built-in speaker.

BACKGROUND

A mobile terminal with a built-in speaker has conventionally been proposed. In the mobile terminal, the speaker is disposed at a given angle in a corner portion of a housing to achieve size and thickness reduction of the mobile terminal.

SUMMARY

A mobile device is disclosed. In one embodiment, a mobile device comprises a display, a battery disposed on the back side of the display, and a film speaker disposed on the back side of the battery.

DETAILED DESCRIPTION

With reference toFIG. 1AandFIG. 1B, a mobile device (for example, a mobile phone)10in one embodiment is a smartphone as an example. An external appearance of the mobile device10includes a back panel12, part of a mounting frame14, and a front panel16so as to have an elongated flat rectangular shape, for example. It is previously pointed out that the disclosure is applicable to not only the smartphone but also any mobile devices such as a tablet PC (Personal Computer) and a PDA (Personal Digital Assistant).

A touch panel20may be formed integrally with the front panel16. Further, a display18(display unit) includes for example, liquid crystals or organic EL (Electro-Luminescence) bonded to a back surface of the front panel16.

A hole22for inputting sound to a microphone located inside the mobile device10is positioned on the right side of a lower side surface of the mobile device10. A built-in piezoelectric element (not shown) for converting a sound signal to vibrations is included on the upper side of the mobile device10. For example, when a sound signal is input to the piezoelectric element, the piezoelectric element converts the sound signal to vibrations and directly vibrates the display18(front panel16). This allows a user to hear the sound output from the display18. Since the sound is output in this manner, the mobile device10may not be supplied with a sound emitting hole for outputting a received voice, for example.

A first film speaker30aand a second film speaker30bthat are described below are built in the mobile device10. Sounds from the first film speaker30aand the second film speaker30bare output from not only two first sound emitting holes24alocated in a back surface of the back panel12but also two second sound emitting holes24blocated in side surfaces of the back panel12in one embodiment.

A hole26connected to a charging terminal (not shown) located inside is located in the middle of the lower side surface of the mobile device10.

For example, when an operation of a call is performed to start the voice call, a received voice is output from the front panel16by vibrations of the piezoelectric element mentioned above. On the other hand, a speaking voice of a user is input to the microphone through the hole22and transmitted to a phone at the other end of the call. When an incoming call from the other phone is notified, a ringer tone is output from a built-in film speaker. The first film speaker30aand the second film speaker30bare built in the mobile device10in one embodiment, so that a stereo sound can also be reproduced.

When a charging connector is connected to the charging terminal through the hole26, a secondary battery44(seeFIG. 3) of the mobile device10can be supplied with charging power from an external power supply.

FIG. 2Aillustrates an explanatory diagram showing an external appearance of a film speaker30used in one embodiment when viewed from the front.FIG. 2Billustrates a cross-sectional view taken along a IIB-IIB line illustrated inFIG. 2A. In addition, the film speaker30illustrated in this diagram is used as the first film speaker30aand the second film speaker30bbuilt in the mobile device10, and thus descriptions are given here without differentiating between a first film speaker and a second film speaker. Hereinafter, to differentiate between the first film speaker and the second film speaker, reference numbers30aand30bare respectively used.

The film speaker30is a flat rectangle and has a thickness of 0.7 mm, for example. The film speaker30comprises a piezoelectric element32having the same rectangular shape. The piezoelectric element32is located substantially in the center of the film speaker30when viewed from a surface of the film speaker30from which sound is output, namely, the front (FIG. 2A) of the film speaker30. The piezoelectric element32is resin-coated with a resin coating layer34. A resin film36is bonded to a surface of the resin coating layer34. A frame38is located on the periphery of the film speaker30to support the resin coating layer34and the resin film36. The application of a sound signal to the piezoelectric element32of such a film speaker30causes the piezoelectric element32to vibrate, and the vibrations are transmitted to the entire film speaker30comprising the resin coating layer34and the resin film36, so that the sound is output from the front of the film speaker30. In addition, the frame38is used when the film speaker30is fixed on a speaker holder46(described below).

FIG. 3illustrates an exploded perspective view showing an outline of an internal structure of the mobile device10. With reference toFIG. 3, the mobile device10comprises the front panel16, the display18, an inner chassis42, the secondary battery44, the first film speaker30aand the second film speaker30b, the mounting frame14, a substrate48, a coupling member56, and the back panel12, and each part is mounted in the mobile device10in the stated order from the front (upper side inFIG. 3). The back panel12is mounted and cooperates with the mounting frame14to create space inside the back panel12, and thus sounds from the first film speaker30aand the second film speaker30bare emitted from the first sound emitting holes24aand the second sound emitting holes24bto the outside of the space.

The main surface of the mobile device10includes the surface of front panel16. The front panel16may be made of a glass so as to have an elongated flat rectangular shape, for example. As described above, the touch panel20may be formed integrally with the back surface of the front panel16. The display18is bonded to the back surface of the front panel16with an adhesive or an optical clear adhesive (OCA) tape.

The inner chassis42comprises a rectangular resin frame and a shield plate40of metal (conductive material) located so as to cover almost the entire surface of the inside of the frame. The frame of the inner chassis42has a thickness equal to or slightly thinner than a thickness of a set of the shield plate40and the secondary battery44in layers. The front panel16to which the display18is bonded as described above is disposed on the front side of the inner chassis42, namely, the front side of the shield plate40. On the other hand, a recessed portion (not shown) for retaining the secondary battery44(allowing the secondary battery44to be fit therein) is provided on the back side of the inner chassis42. Therefore, the secondary battery44is disposed on the back side of the display18with respect to the shield plate40. The inner chassis42stably retains the secondary battery44on the back side of the display18. In addition, the inner chassis42, particularly the resin frame, is sometimes referred to as a battery retainer.

FIG. 4Aillustrates a plan view showing an example of the mounting frame14when viewed from the front (also referred to as the front side), andFIG. 4Billustrates a plan view showing an example of the mounting frame14when viewed from the back side. With reference toFIG. 4AandFIG. 4Btogether withFIG. 3, the mounting frame14has a planar rectangular shape similarly to the front panel16and the inner chassis42. A frame comprising a pair of vertical frames70(first pair of frame members) and a pair of horizontal frames72(second pair of frame members) may be formed together with each part described below by resin molding. Hereinafter, one and the other of the vertical frames70in a pair are also referred to as a first vertical frame70aand a second vertical frame70b, respectively, and one and the other of the horizontal frames72in a pair are also referred to as a first horizontal frame72aand a second horizontal frame72b, respectively. The first vertical frame70aand the second vertical frame70bare disposed at a predetermined interval. The first horizontal frame72aconnects the upper portions of the pair of the vertical frames70to each other. The second horizontal frame72bconnects the lower portions of the pair of the vertical frames70to each other.

A first speaker holder46aand a second speaker holder46bboth having a plate shape are formed so as to extend inwardly respectively from the inside of the first vertical frame70aand the inside of the second vertical frame70band to face each other in the direction in which they extend. Sound emitting holes74having a hexagonal shape, for example, are each formed in the center of the first speaker holder46aand the second speaker holder46bto emit sounds from the first film speaker30aand the second film speaker30b(FIG. 5B, for example) retained in the first speaker holder46aand the second speaker holder46b.

The first speaker holder46aand the second speaker holder46bhave ribs90(seeFIG. 9), which are described in detail below, on the peripheries of the front surfaces of the first speaker holder46aand the second speaker holder46b. The first speaker holder46aand the second speaker holder46bhave the planar rectangular plate shape in one embodiment, but the shape of the first speaker holder46aand the second speaker holder46bis not limited to this. It suffices that the first speaker holder46aand the second speaker holder46beach have at least a region in which the frame38inFIG. 2AandFIG. 2Bcan be mounted (bonded). The sound emitting holes74may be larger or smaller.

The inner chassis42is fit in the frame of the mounting frame14. Thus, the inner surfaces of the pair of vertical frames70and the pair of horizontal frames72have an interior wall surface60(also seeFIGS. 6 and 8, for example) in which the inner chassis42can be fit. In other words, the interior wall surface60contacts the outer surface of the resin frame of the inner chassis42, so that the inner chassis42is fit in the mounting frame14.

Moreover, the mounting frame14has a panel supporter62and an interior wall surface64(also seeFIGS. 6 and 8, for example) for housing the front panel16and allowing the front panel16to be mounted thereon. The panel supporter62and the interior wall surface64as well as the interior wall surface60have a step shape. More specifically, the panel supporter62is a planar portion extending outwardly from an end of the interior wall surface60on the front side of the mounting frame14(an end toward the front of the paper plane inFIG. 4AandFIG. 4B, and an end on the lower side of the paper plane inFIG. 6). The interior wall surface64extends from the outer end of the panel supporter62to the front side (the side toward the front of the paper plane inFIG. 4AandFIG. 4B, and the lower side of the paper plane inFIG. 6). The peripheral portion of the front panel16is disposed on the panel supporter62. Thus, the front panel16is housed inside the interior wall surface64.

A portion66(also seeFIGS. 6 and 8, for example), which is located outside the interior wall surface64, of each of the pair of vertical frames70and the pair of horizontal frames72is an exposed portion that is exposed as the exterior appearance (FIG. 1AandFIG. 1B) of the mobile device10. Therefore, when the front panel16is mounted inside the interior wall surface64and on the panel supporter62, the front surface of the front panel16is in the same plane or substantially the same plane as (is flush with) the front surface of the outer portion66.

An assembly portion76on which parts such as a camera module are assembled is located from the inside of the first horizontal frame72ato the upper ends of the first speaker holder46aand the second speaker holder46b. The assembly portion76has a rectangular hole78for allowing wiring to pass therethrough. Two substrate recessed portions80for allowing the substrate48with the shape illustrated inFIG. 3to be disposed thereon are located in the assembly portion76on the back side (FIG. 4B) of the mounting frame14. As seen fromFIG. 3, the side surface of the second horizontal frame72bhas a hole22aconnected to the microphone and a hole26aconnected to the charging terminal.

Referring back toFIG. 3, the substrate48is made of resin, glass fiber, or the like, and has a first portion50, a second portion52having a substantially rectangular shape, and a third portion54that has an elongated shape and connects the first portion50and the second portion52to each other. The substrate48comprises predetermined wiring formed thereon and comprises necessary parts such as the microphone mounted thereon.

It should be noted that the shape and the size of the first portion50, the second portion52, and the third portion54of the substrate48are not limited to the shape and the size in one embodiment.

The coupling member56is made of resin or the like and has a body portion and two locking portions82(seeFIG. 6) located on each of the left and the right of the body portion. The coupling member56couples the inner end portions, which face each other, of the first speaker holder46aand the second speaker holder46b. A means of mounting the coupling member56is described in detail below.

The side surfaces and the bottom surface (back surface) of the mobile device10includes a surface of the back panel12as illustrated inFIG. 1AandFIG. 1B. The back panel12may be made of resin so as to have a rectangular box shape. The bottom surface of the back panel12has the first sound emitting holes24a, and the left and right side surfaces of the back panel12have the second sound emitting holes24b. The lower side surface of the back panel12has a hole22bconnected to the microphone and a hole26bconnected to the charging terminal.

The inner chassis42, the secondary battery44, the first film speaker30a, the second film speaker30b, the substrate48, and the coupling member56that are described above are mounted in the mounting frame14. Then, the front panel16is mounted on the front side of the mounting frame14in which they are mounted, and the back panel12is mounted on the back side of the mounting frame14.

Next, a procedure for mounting parts in the mounting frame14is described. First, with reference toFIG. 5AandFIG. 5B, the first film speaker30aand the second film speaker30bare respectively bonded to the first speaker holder46aand the second speaker holder46bwith bonding means such as a double-faced tape on the front side of the mounting frame14. At this time, the first film speaker30aand the second film speaker30bare bonded such that each of the surfaces from which sounds are emitted, namely, the front surface faces the corresponding sound emitting hole74. The bonding means such as the double-faced tape (OCA tape) bonds the frames38, which are illustrated inFIG. 2AandFIG. 2B, of the first film speaker30aand the second film speaker30bto the corresponding first speaker holder46aand second speaker holder46b. While the first film speaker30aand the second film speaker30bare bonded to the first speaker holder46aand the second speaker holder46b, the first film speaker30aand the second film speaker30bcan be visually identified through the sound emitting holes74from the back side of the mounting frame14.

With reference toFIG. 5CandFIG. 5D, the substrate48is disposed on the back side of the mounting frame14. At this time, the first portion50of the substrate48is disposed above the first speaker holder46aand the second speaker holder46bsuch that the first portion50overlaps part of the assembly portion76, and the second portion52is disposed below the first speaker holder46aand the second speaker holder46b. The third portion54passes between the first speaker holder46aand the second speaker holder46band is disposed in substantially the same plane as the first film speaker30aand the second film speaker30b. As a result, the hole78and the substrate recessed portions80in the assembly portion76are covered with the substrate48. The substrate48is disposed on the back side of the mounting frame14so as to avoid the first film speaker30aand the second film speaker30b. Thus, for example, the first film speaker30aand the second film speaker30bcan be disposed in the same plane or substantially the same plane as the substrate48, so that the thickness can be further reduced. Moreover, the third portion54connects the first portion50and the second portion52to each other, and the coupling member56over the third portion54couples the first speaker holder46aand the second speaker holder46b. Thus, the first speaker holder46aand the second speaker holder46bhaving great rigidity can be realized without reducing an area that can be used for the substrate48.

Next, as illustrated inFIG. 5D, the coupling member56over the third portion54of the substrate48is locked to the first speaker holder46aand the second speaker holder46bsuch that the coupling member56couples the inner end portions, which face each other, of the first speaker holder46aand the second speaker holder46b.

Specifically, with reference toFIG. 6that is a cross-sectional view taken along a VI-VI line inFIG. 5D, each of the locking portions82located on the coupling member56has a hook on the tip. When the coupling member56on the back side of the mounting frame14is pushed from the upper side of the paper plane inFIG. 6, the locking portions82are temporarily bent inwardly. When the coupling member56is further pressed and the tips of the locking portions82reach the front side of the mounting frame14, the shape of the locking portions82returns to the original shape. At this time, the hooks located on the tips of the locking portions82are caught on the peripheries of the first speaker holder46aand the second speaker holder46b, and thus the coupling member56is fixed between the first speaker holder46aand the second speaker holder46b.

As a result, the first speaker holder46aand the second speaker holder46bare in the state of being firmly coupled together with the coupling member56, so that the first speaker holder46aand the second speaker holder46bhave a both-end supported beam structure from a cantilever structure (the state inFIG. 4AandFIG. 4B, for example). In this manner, the first speaker holder46aand the second speaker holder46bare integrated, so that each of them has greater rigidity, and vibrations of the first speaker holder46aand the second speaker holder46bthemselves can be suppressed. Thus, sound pressure levels of the first film speaker30aand the second film speaker30bcan be increased.

For example, in a case where the first speaker holder46aand the second speaker holder46bare not coupled together with the coupling member56, the first speaker holder46aand the second speaker holder46bremain in the cantilever structure, and the structure supporting the first film speaker30aand the second film speaker30bdoes not have great rigidity. If sounds are emitted from the first film speaker30aand the second film speaker30bin this state, the vibrations of the first film speaker30aand the second film speaker30balso cause the first speaker holder46aand the second speaker holder46bto vibrate, and the vibrations of the first speaker holder46aand the second speaker holder46bcan diminish the vibrations of the first film speaker30aand the second film speaker30b. On the other hand, if the first speaker holder46aand the second speaker holder46bare coupled together with the coupling member56and have the both-end supported beam structure as in one embodiment, approximately 3 dB of improvement in the sound pressure can be seen.

As illustrated inFIG. 6, the mounting frame14is tilted from the center toward the first vertical frame70aand the second vertical frame70b, and the central portion is located higher than the first vertical frame70aand the second vertical frame70b. In a case where the back panel12is mounted on the mounting frame14, an adhesive is applied to the coupling member56, and the coupling member56and the back panel12are bonded together. In other words, the coupling member56is also fixed on the back panel12. Therefore, the first speaker holder46aand the second speaker holder46bare reinforced also with the back panel12, and the further improvement in the sound pressure is promising.

In another embodiment, the coupling member56may have a recessed portion to suppress a leak of the adhesive applied to the coupling member56.

FIG. 7Aillustrates an explanatory diagram showing a state of the mounting frame14illustrated inFIG. 5Dbefore the inner chassis42is fit in the mounting frame14.FIG. 7Aillustrates a diagram when viewed from the front (front side), and the substrate48and the coupling member56are mounted on the mounting frame14in one example ofFIG. 7A. In this state, part of the substrate48is seen through the hole78. Further, the hooks on the tips of the locking portions82of the coupling member56are caught on the right side of the first speaker holder46aand the left side of the second speaker holder46b. As illustrated inFIG. 7A, the coupling member56couples the first speaker holder46aand the second speaker holder46bsuch that the locking portions82are fit in part of slits92(described below) of the first speaker holder46aand the second speaker holder46b.

With reference toFIG. 7B, the inner chassis42retaining the secondary battery44is fit in the mounting frame14in this state, and thus the inner chassis42covers the substrate48, the first film speaker30a, the second film speaker30b, the first speaker holder46a, the second speaker holder46b, or the like. InFIG. 7B, the secondary battery44is indicated by a broken line.

With reference toFIG. 8illustrating a cross-sectional view taken along a VIII-VIII line inFIG. 7B, it is clearly seen that the inner chassis42retains the secondary battery44. The secondary battery44is disposed on the mounting frame14and the shield plate40, so that the secondary battery44is difficult to come off the inner chassis42.

Then, the first film speaker30aand the second film speaker30bare in the state of being retained on the back side of the secondary battery44by the first speaker holder46aand the second speaker holder46b. In other words, the first speaker holder46aand the second speaker holder46bstably retain the first film speaker30aand the second film speaker30bon the back side of the secondary battery44.

At this time, the first film speaker30aand the second film speaker30bare disposed side by side on the back side of the secondary battery44, so that the two sound sources are not too far away from each other, and a monophonic sound and a stereo sound tend to sound natural when being reproduced.

In this manner, the mobile device10as a whole can be reduced in thickness by using the film speakers and disposing the film speakers on the back side of the secondary battery.

As illustrated inFIG. 8, the inner chassis42retaining the secondary battery44is fit in the interior wall surface60of the mounting frame14. The frame of the inner chassis42has a thickness including a thickness of the shield plate40and a thickness of part of the secondary battery44. The mounting frame14has a thickness including the thickness of the shield plate40, the thickness of the inner chassis42, and the thickness of the secondary battery44. Thus, even when the inner chassis42including the secondary battery44fit therein is fit in the mounting frame14, the thickness of the mounting frame14remains unchanged. In other words, the secondary battery44and the inner chassis42are completely housed inside the mounting frame14and do not protrude from the mounting frame14. This configuration also allows the mobile device10as a whole to be reduced in thickness.

FIG. 9AandFIG. 9Billustrate enlarged views showing details of the first speaker holder46aand the second speaker holder46b. With reference toFIG. 9A, the peripheries of the first speaker holder46aand the second speaker holder46bare surrounded by the ribs90. The ribs90have a height set to be higher than a thickness (height) of the first film speaker30aand the second film speaker30bbonded to the first speaker holder46aand the second speaker holder46b. Therefore, when the first film speaker30aand the second film speaker30bare bonded to the first speaker holder46aand the second speaker holder46b, the ribs90are higher than the first film speaker30aand the second film speaker30b. In other words, the ribs90protrude to the front side (toward the secondary battery44) more than the first film speaker30aand the second film speaker30b. The rib90of the first speaker holder46ahas slits92at a total of 12 places including 4 places on the upper side, 4 places on the lower side, and 4 places on the right side (center side of the mobile device10). The rib90of the first speaker holder46ahas a wiring recessed portion94on the right side thereof to allow wiring connected to the first film speaker30ato pass through the wiring recessed portion94. Similarly, the rib90of the second speaker holder46bhas the slits92at a total of 12 places including 4 places on the upper side, 4 places on the lower side, and 4 places on the left side (center side of the mobile device10), and has the wiring recessed portion94on the left side of the rib90. The slits92are disposed at an interval on the periphery of each of the first speaker holder46aand the second speaker holder46b. The slits92have openings on the secondary battery44side while penetrating the ribs90in a parallel direction to the substrate48(in a parallel direction to the paper plane ofFIG. 9). It should be noted that the number and the size (length or width) of the slits92are not limited to those in one embodiment.

With reference toFIG. 9B, when the first film speaker30aand the second film speaker30bare mounted in the first speaker holder46aand the second speaker holder46b, the first speaker holder46aand the second speaker holder46bretain the first film speaker30aand the second film speaker30bwhile the ribs90surround the first film speaker30aand the second film speaker30b.

FIG. 10illustrates a diagram of the first speaker holder46aand the second speaker holder46billustrated inFIG. 9Bwhen viewed from the back side. In one example ofFIG. 9B, the secondary battery44is disposed on the front side of the mounting frame14. In this state, the front of the first film speaker30aand the front of the second film speaker30bare seen through the sound emitting holes74of the first speaker holder46aand the second speaker holder46b. The first film speaker30aand the second film speaker30bare in the state of being disposed on the back side of the secondary battery44.

FIG. 11illustrates a cross-sectional view taken along an XI-XI line inFIG. 10and mainly illustrates a section of the rib90of the first speaker holder46aretaining the first film speaker30a. With reference toFIG. 11, the upper end face (lower side inFIG. 11) of the rib90faces the back surface of the secondary battery44. The rib90is higher than the first film speaker30, and thus substantially the entire first film speaker30ais covered with the rib90and part of the first film speaker30acan be confirmed through the slits92in the cross-sectional view. The upper end face of the rib90higher than the first film speaker30afaces the secondary battery44, to thereby keep a gap between the secondary battery44and the first film speaker30a. In other words, in a case where the secondary battery44is expanded over time by being repeatedly charged and discharged, the rib90functions as a stopper and the upper end face of the rib90contacts the main surface of the expanded secondary battery44. Therefore, the main surface of the secondary battery44is difficult to be further displaced toward the first film speaker30a. Therefore, the rib90can stably keep the gap between the first film speaker30aand the secondary battery44.

With the rib90surrounding the first film speaker30a, the inner space and the outer space of the rib90that houses the first film speaker30aor the second film speaker30bcommunicate with each other through the slits92. Thus, a rear volume of the first film speaker30acan be sufficiently kept, and acoustic performance of the first film speaker30acan be improved.

The rib90located on the upper side and the left side (center side) of the first speaker holder46a, the rib90of the second speaker holder46b, and the second film speaker30bare substantially the same as those inFIG. 11, and thus detailed drawings are omitted.

With reference toFIG. 12, in another embodiment, the first speaker holder46a(for example, the rib90) may be fixed on (bonded to) the secondary battery44with a fixing portion such as an adhesive96or fixing means to further improve the sound pressure level of the first film speaker30a. The first speaker holder46ais fixed on the secondary battery44by using the secondary battery44having the greatest weight in the mobile device10and great rigidity as in one embodiment.

The second speaker holder46b(for example, the rib90) may be bonded to the secondary battery44with the adhesive96or the like similarly to the first speaker holder46a, which is omitted from the diagram.

In one embodiment inFIG. 12as described above, the rib90, for example, is fixed on the secondary battery44, and the rib90and the secondary battery44are integrated, so that the rigidity of the first speaker holder46aand the second speaker holder46bis reinforced with the rigidity of the secondary battery44, to thereby further increase the rigidity of the first speaker holder46aand the second speaker holder46b. As a result, the vibrations of the first speaker holder46aand the second speaker holder46bcaused by the vibrations of the first film speaker30aand the second film speaker30bcan be suppressed. Consequently, the sound pressure levels of the first film speaker30aand the second film speaker30bcan be increased.

By fixing the first speaker holder46aand the second speaker holder46bon the secondary battery44, the first film speaker30aand the second film speaker30bcan keep a fixed distance from the secondary battery44at the occurrence of the phenomenon in which the secondary battery44is expanded over time by being repeatedly charged and discharged. Thus, variations in the rear volume of the first film speaker30aand the second film speaker30bcan be suppressed.

In one embodiment inFIG. 12, the first speaker holder46aand the second speaker holder46bmay be fixed on the secondary battery44with a double-faced tape or a fitting (locking) mechanism.

Further, in one embodiment described above, the substrate48includes the first portion50, the second portion52, and the third portion54, but the shape of the substrate48may be modified in various ways.

For example, the substrate48may be formed as one large rectangular substrate and may be disposed so as to overlap the mounting frame14. In this case, it cannot be expected that the substrate48is reduced in thickness by being disposed between the first film speaker30aand the second film speaker30b, but the first speaker holder46aand the second speaker holder46bdo not need to be located separately. Thus, the both-end supported beam structure is applicable as the structure of the first speaker holder46aand the second speaker holder46bwithout using the coupling member56, which can increase the rigidity.

Alternatively, the substrate may have only a part corresponding to only the second portion50. Also in this case, the first speaker holder46aand the second speaker holder46bthat are integrated can be formed while the coupling member56is omitted.

In one embodiment, the first film speaker30a, the second film speaker30b, and the ribs90have the rectangular shape, but at least any one of them may have a circular shape or another shape instead of the rectangular shape in another embodiment.

In one embodiment, the ribs90are formed so as to surround the first film speaker30aand the second film speaker30b, that is to say, the ribs90are formed all around the first film speaker30aand the second film speaker30b. In still another embodiment, the ribs90may include only ribs corresponding to at least one side of the first film speaker30aand the second film speaker30b. The ribs90may not surround the first film speaker30aand the second film speaker30b.

One embodiment described above comprises the two film speakers30a,30b, but the film speaker30may comprise only one of them to further reduce the mobile device in size or to further increase the inner space. In this case, only one group of the first sound emitting holes24aare located in the main surface of the housing member, and only one group of the second sound emitting holes24bare located in positions corresponding to the first sound emitting holes24ain the side surface of the housing member. In the case where only one film speaker30is used as described above, sounds may be output from both of the first sound emitting holes24aand the second sound emitting holes24blocated at some distance from the first sound emitting holes24a, thereby providing a better sense of realism than the case where only the first sound emitting holes24aare formed.

Any specific numeric values in the disclosure are merely an example, and may be changed suitably according to modifications of specifications of products.

Some examples of the points in one embodiment are summarized below. In a first aspect of one embodiment, a mobile device comprises a display, a battery disposed on the back side of the display, and a film speaker disposed on the back side of the battery.

A second aspect of one embodiment is dependent on the first aspect. The mobile device further comprises a speaker holder retaining the film speaker on the back side of the battery.

A third aspect of one embodiment is dependent on the second aspect. The speaker holder retains the film speaker inside the speaker holder and comprises a rib higher than a thickness of the film speaker, an upper end face of the rib facing the battery.

A fourth aspect of one embodiment is dependent on the third aspect. At least part of the rib has a slit.

A fifth aspect of one embodiment is dependent on the third aspect or the fourth aspect. The mobile device further comprises a fixing portion fixing the rib on the battery.

A sixth aspect of one embodiment is dependent on any of the second aspect to the fifth aspect. The film speaker comprises a first film speaker and a second film speaker, and the speaker holder comprises a first speaker holder retaining the first film speaker and a second speaker holder retaining the second film speaker.

A seventh aspect of one embodiment is dependent on the sixth aspect. The mobile device further comprises a mounting frame that comprises a first pair of frame members disposed at an interval and a second pair of frame members coupling the first pair of frame members. The first speaker holder and the second speaker holder are formed so as to extend inwardly from the inside of each of the first pair of frame members and to face each other.

An eighth aspect of one embodiment is dependent on the seventh aspect. The mobile device further comprises a coupling member coupling inner end portions, which face each other, of the first speaker holder and the second speaker holder.

A ninth aspect of one embodiment is dependent on the eighth aspect. The mobile device further comprises a substrate having a first portion, a second portion, and a third portion that connects the first portion and the second portion to each other. The third portion of the substrate passes between the first speaker holder and the second speaker holder and is disposed in the same plane or substantially the same plane as the first film speaker and the second film speaker. The coupling member over the third portion of the substrate couples the first speaker holder and the second speaker holder.

A tenth aspect of one embodiment is dependent on any of the seventh aspect to the ninth aspect. The mobile device further comprises a battery retainer retaining the battery on the back side of the display. The battery retainer is mounted in the mounting frame while retaining the battery.

An eleventh aspect of one embodiment is dependent on any of the first aspect to the tenth aspect. The mobile device further comprises a back panel having a sound emitting hole.

The disclosure is described in detail, but the above description is the exemplification in all aspects and embodiments of the present disclosure are not intended to be limited thereto. It is construed that numerous modifications which are not exemplified can be envisaged without departing from the scope of the present disclosure.