Field of the Invention

The present invention relates to earphones, in particular in-ear monitors, which are adapted to fit within the ear canal of a user. Background Art

There is a variety of devices for fitting in or over the ear for providing audio sound waves to the listener. Headphones usually comprise cushioned disc-like devices which enclose the ear and are joined by a band fitting over the head. Ear buds are small discs dimensioned to fit within the outer ear, and are commonly used in portable situations. In-ear monitors, otherwise known as in- ear headphones, in-ear earphones, canal phones, are small elements which are shaped so as to be inserted in the ear canal itself.

In-ear monitors commonly employ balanced-armature speakers, which, in contrast to conventional loudspeakers with flexible cone diaphragms, comprise a drive rod which moves back and forth, under the influence of drive magnets, to drive a metal foil sheet. The structure is mounted within a box, and resulting sound waves are transmitted through an open port in a side wall of the box. Such balanced-armature speakers may be made very small in size, and can therefore fit within in-ear monitors. An example of an in-ear monitor is manufactured by ACS (Advanced

Communication Solutions) and is disclosed in http://acscustom.com/uk/product- category/in-ear-monitors . It comprises a silicone moulding which fits closely within the ear canal and may be custom moulded for the particular user, and since they provide very high quality sound reproduction, they are commonly used by professionals within the music industry.

A less expensive in-ear monitor which has been manufactured by ACS for less demanding users, http://acscustom.com/uk/product/acs-t15-single- driver-universal-fit-ear-monitors/ , known as universal fit device, comprises a balanced armature speaker mounted within a hollow rigid shell, and with a sound output port coupled to the ear canal by means of a soft flexible ear tip device which fits within the ear. Traditionally earphones are designed to have a hollow plastic or metal body design and either a dynamic or balanced armature receiver. Due to the resonant space within the earphone housing the resulting presentation of the sound can be tinny and analytic sounding with little emotion and warmth to the sound.

Summary of the Invention

It is an object of the invention to avoid the tinny and analytic sound which may occur with hollow body designs, but to maintain the cost of in-ear monitors well below silicone moulding devices as described above, which may be very expensive.

Embodiments of the invention provide universal fit in-ear earphone monitors which feature a soft pliable material such as silicone, rubber or foam as a backfill that encases balanced armature speakers (otherwise known as receivers) within a rigid outer shell of the earphone. The method of using these materials to surround the balanced armature speakers gives the earphones a distinct sound with smooth deep lows, detailed midrange and crystal clear highs. The sound signature is warm, smooth and well balanced which is very difficult to achieve in traditional earphones. Not only does the backfill material improve the acoustics of the earphone it also increases the isolation, meaning less sound leakage out of the earphone and higher attenuation of outside noise.

An embodiment of the invention may employ a wide band balanced armature speaker which is ported, by which is meant the casing or shell of the speaker has an air outlet port to give a better low-end response. For the porting to be effective, a surrounding volume of air is provided, communicating with the air outlet port and of a volume equal to at least half the volume of the speaker. Embodiments provide a dual function speaker housing that retains the speaker in a fixed position within the earphone body and forms an air chamber to a precise specification to provide an exact volume of air to deliver an optimum audio response. The additional air space in the earphone cavity is filled with the backfill material to provide a secure mount for the speaker and dual function housing, increase isolation and to ensure the highest possible audio quality.

In another embodiment, a plurality of balanced armature speakers are provided, held in position by means of a holder framework. The speakers have different frequency response for low end and high end of the audio spectrum. In this case it is not necessary to port the speakers, nor to provide coupled air compartments. In consequence the silicone backfill will wholly envelop the speakers and contact all exposed sides of the speakers and cradle assembly.

In one aspect, the invention provides an in-ear monitor for fitting within the ear canal of a user, the monitor comprising a body part and an audio outlet port, and a flexible ear tip for fitting over said outlet port and within said ear canal, the body part comprising a shell in which is mounted at least one balanced armature speaker, and interior space within said shell being at least partially filled with a moulding of sound transmissible material which contacts and envelops said balanced armature speaker.

In another aspect, the invention provides an in-ear monitor for fitting within the ear canal of a user, the monitor comprising a body part and an audio outlet port adapted to receive a flexible ear tip for fitting within said ear canal, the body part comprising a shell in which is mounted at least one balanced armature speaker, and interior space within said shell being at least partially filled with a moulding of sound transmissible material which contacts and envelops said balanced armature speaker.

As preferred said moulding is injected into the shell (which may be formed of a rigid impact resistant material) subsequent to assembly of the interior parts, and wholly fills the available space within the shell, making contact with the inner surface of the shell, and the outer surfaces of said balanced armature speaker. Nevertheless, it is preferred to provide an air space within the shell, communicating with an air outlet port in the casing of said balanced armature speaker of a defined volume, about half the volume of said balanced armature speaker. This air space may be provided by creating an occlusion with said moulding, for example with the aid of interior walls extending from the shell. Alternatively a separate housing may be provided within which said balanced armature speaker and the air space is contained. As preferred a housing is provided which fits over a surface of said balanced armature speaker which contains the air outlet port, and is constructed as will be explained to ensure no air leakage, and to ensure that the speaker is accurately located to the housing. Structural supports which project from the inner surface of the shell serve accurately to position the speaker and housing within the shell. The backfill ensure that the speaker and housing remain fixed in the predefined position throughout use.

In another embodiment, a plurality of speakers, for example having different frequency responses, may be mounted within a holder framework, to ensure accurate location, and the framework is accurately located within the shell by means of structural supports which project from the inner surface of the shell. In this embodiment, an air compartment may not be provided. The backfill ensure that the framework remains fixed in the predefined position throughout use.

Thus, said at least one balanced armature speaker is securely held and positioned within the outer shell, firstly by being fixed within a holder, the holder being secured to an inner surface of the outer shell, preferably on opposing sides of the inner surface. The silicone backfill cements the holder and speaker in position. An audio outlet manifold of the speaker is bonded within an outlet aperture of the shell communicating with said audio outlet port, to ensure that the outlet port does not get obstructed.

As preferred, the moulding material is a high grade silicone, for example with a Shore factor of about 40. However other materials such as rubber or foam may be employed with beneficial results.

A set of ear tips may be provided with earphones of the present invention, to suit different users. The ear tips may be of conical form, as a series (three) of part-conical sections. Alternatively they may be formed of expanding foam material. Alternatively, the earphones may be provided without ear tips, e.g. as a replacement for users that already have ear tips.

Brief Description of the Drawings

Preferred embodiments of the invention will now be described with reference to the accompanying drawings wherein:

Figure 1 shows a first embodiment of the earphone of the present invention fully assembled;

Figure 2 is an exploded diagram of the first embodiment in assembly order;

Figure 3 is a side perspective view of a first case part of the outer shell;

Figure 4, 5 and 6 are close up views of shows an alignment cut-out (17), securing latches (16) and alignment pin (19);

Figure 7 is a perspective view of interior parts of the first case part of the outer shell;

Figure 8 is a side view of a sound outlet hole (20) and structural support (21);

Figure 9 is a close up of structural supports (23);

Figure 10 shows interior structures of the second case part of the outer shell of the first embodiment;

Figure 11 is a side view of the second shell case part (5) with socket (4) installed;

Figures 12 to 15 are close up views of interior parts of the second shell part; Close up of socket (4) seated in supported area (25), Close up of supports (27) for speaker (9), close up of support (29) for speaker housing (10, 1 1), and close up of locating lug (26),

Figure 16 shows a second embodiment of the earphone of the present invention fully assembled;

Figure 17 is an exploded diagram of the second embodiment in

assembly order; Figure 18 is a plan view of the second case part of the outer shell of the second embodiment;

Figure 19 is a side view of the second case part of the outer shell;

Figures 20 to 22 are close up view interior parts of the second shell part of the second embodiment,

Figure 23 is a side view of the first part of the shell of the first

embodiment partially assembled; transparency has been provided to allow visibility of how said parts interact with one another;

Figure 24 is a perspective view of the speaker and attached air compartment housing of the first embodiment housing; transparency of said speaker housing has been left on to show how the air chamber is created.

Figure 25 is a top down view of first part of the shell of the first

embodiment, without backfill;

Figure 26 is a top down view of first part of the shell of the first

embodiment, with backfill; blue shaded area represents the silicone backfill;

Figure 27 is a side view of the first part of the shell of the second embodiment partially assembled; transparency has been provided to allow visibility of how said parts interact with one another;

Figure 28 is a perspective view of the speaker and attached air compartment housing of the second embodiment;

Figure 29 is a top down view of the first part of the shell of the second embodiment, without backfill;

Figure 30 is a top down view of first part of the shell of the second embodiment, with backfill; blue shaded area represents the silicone backfill;

Figure 31 comprises a side partially transparent view of the speakers of the second embodiment, held within a holder framework, and the manifolds for the audio output of the speakers;

Figure 32 is a perspective view of the holder framework of the second embodiment;

Figure 33 comprises perspective views of a first version of a housing for said balanced armature speaker of the first embodiment and defining a specific air volume in communication with the speaker; and Figure 34 comprises perspective views of a second version of a housing for attaching to a balanced armature speaker of the first embodiment and defining a specific air volume in communication with the speaker;

Description of the Embodiments

Note: In embodiments of the invention, left and right earphones are provided for fitting in respective ears. There is one earphone for the Left ear and one for the Right ear; the case parts are marked L & R appropriately. For the purposes of this specification, only the Left side is shown. As a final product there will include an identically assembled Right hand side, making a pair of earphones where the only differences are the L & R markings and the orientation and fitting of the earphones into the users' ears accordingly.

Reference will now be made to Figures 1 to 15, 33, which show the first embodiment. However certain of the parts of the first embodiment are common to the second embodiment shown in figures 16 to 22, and reference will be made to the second embodiment, where appropriate, similar parts being denote by the same reference numeral.

Fig. 1 shows the first embodiment fully assembled, wherein;

Ref 1 The ear tip port (1) providing the audio outlet port has an enlarged boss at its free end for receiving a flexible ear tip.

Ref 2 The first case part (2) of the outer shell, of rigid impact resistant material, of both embodiments.

Ref 3 The earphones have been designed so that when case part (2) and second outer shell cover part (5) (30, Figure 16) are joined there is a small gap to ensure a flush join between said parts.

Ref 4 Socket for electrical cable system of the earphone.

Ref 5 second outer shell case part.

Fig. 2 shows an exploded diagram of the first embodiment in assembly order, wherein:

Ref 6 is a triple flange ear tip of flexible material for fitting closely within an ear canal- this is exemplary, in practice earphones may be shipped with multiple different tips as part of a retail pack. Ref 8 is a speaker manifold, this glues onto the audio outlet of the balanced armature speaker (9) and inserts into the sound outlet hole (20, Figure 7) on the case (2) which communicates with port (1).

Ref 9 Balanced armature speaker which is fixed with glue to the first or top part of the speaker air compartment housing (10) as shown in Fig. 24. The manifold (8) is glued onto the sound port of this speaker and then fixed with glue into the sound outlet hole (20) on the case (2). This ensures a guaranteed seal between said parts and prevents silicone backfill from entering.

Ref 10 Top part of speaker air compartment housing. This part mates with the bottom part of the housing (11) forming the speaker housing assembly which in turn creates the air chamber as shown at 40 in Figs. 24, 33 and communicates with an air port (not shown) in the wall of the speaker housing.

Ref 11 Bottom part of speaker housing. This part mates with the top part of the speaker housing (10) forming the speaker housing assembly which in turn creates the air chamber as shown at 40 in Figs. 24, 33.

Ref 12 Cable which is compatible with the connection system - socket (4) & connector (13) for both L&R earphones. This cable is exemplary only.

Ref 13 Connector which is compatible with the socket (4). This is exemplary only.

Fig. 3 shows side view of first case part (2). The key securing parts, for securing to the second case part (5) are referenced:

Ref 16 Three latches which mate with the three lugs (28, Figure 10) which is found on the second case part (5, 30) for both embodiments. These have been designed to clip together the case parts (2, 5, 30).

Ref 17 Alignment cut-out which mates with alignment lug (26, Figure 10) to aid in the assembly process.

Ref 18 Lip to aid assembly and add strength when case parts (2, 5, 30) are assembled.

Ref 19 Alignment pin mates with alignment hole (24, figure 10) to aid in the assembly process. Fig. 4 Close up of alignment cut-out (17).

Fig. 5 Close up of securing latches (16).

Fig. 6 Close up of alignment pin (19).

Fig. 7 Shows interior details of the first case part (2); wherein:

Ref 20 Sound outlet hole, the speaker manifold part (8) and, for the second embodiment, speaker manifold parts (31 , 32) are fixed with glue into said hole.

Ref 21 Structural support which aligns with speaker housing (10, 11) and speaker holder (35) of second embodiment.

Ref 22 Cut-out shaped to support ideal fit between compatible connector (13) and socket (4).

Ref 23 Structural supports, mate with first embodiment speaker housing (10, 11) and second embodiment speaker holder (35). These ensure that the speaker(s) (9, 33, 34) remain in the ideal position to deliver the best sonic performance.

Ref 36 - the injection hole for a silicone moulding to be made subsequent to assembly of the earphone parts.

Fig. 8 Close up of sound outlet hole (20) and structural support (21).

Fig. 9 Close up of structural supports (23).

Fig. 10 Shows the interior structures of the first embodiment second outer shell case part (5), wherein:

Ref 24 Alignment hole, this aids in the assembly process and mates with alignment pin (19) on the first case part (2).

Ref 25 Shaped support structure which the socket (4) is fixed into with glue. The structure ensures said socket is solidly fixed in the optimum position.

Ref 26 Alignment lug to aid assembly process, mates with cut out (17) on first case part (2).

Ref 27 Supports which prevent movement of the speaker (9) once assembled.

Ref 28 Three lugs to secure first case part (2) and second case part (5) together, mating with latches (16) on case part (2).

Ref 29 Supports, which prevent movement of the speaker housing (10, 11). Fig. 11 is a side view of second cover part (5) with socket (4) installed, this is exemplary to show how the socket sits once fixed in.

Fig. 12 Close up of socket (4) seated in supported area (25) of cover (5) Fig. 13 Close up of supports (27) for speaker (9)

Fig. 14 Close up of support (29) for speaker housing (10, 11)

Fig. 15 Close up of locating lug (26), mates with cut out (17) on case part

(2).

Referring additionally to Figure 33, this shows the two parts 10, 11 of the speaker air compartment housing assembled together to form a rectangular air compartment 40, with ears 42 which extend either side of the speaker to firmly seat the speaker with the housing. An aperture 44 is provided to communicate with the air aperture (not shown) in a side wall of the speaker housing. End stops 46 position the speaker within the housing. Lugs 48 on the opposite side of the housing mate with structural supports 23 (Figure 7), to position the speaker assembly within the housing, and further supports 21 , 27, 29 serve to position the speaker assembly within the outer shell.

Referring now to the second embodiment shown in figures 16 to 22, similar parts to those of the first embodiment are denoted by the same reference numeral.

Fig. 16 shows an exterior view of the earphone of the second embodiment, wherein:

Ref 2 is the first case part, and is similar to that of the first embodiment, and will not be described again in detail;

Ref 30 second case part of the outer shell, which mates with the first case part (2)

Fig. 17 Shows an exploded diagram of the earphone in assembly order Ref 31 speaker manifold top, mates with bottom part (32) and inserts in to sound outlet hole (20) on the case part (2)

Ref 32 speaker manifold bottom, mates with top part (31) & is fixed on to the sound port of two speakers (33, 34). Referring to Figure 31 , this shows manifold parts 31 , 32 in more detail. Part 32 fixes directly onto the outlet ports of both speakers 33, 34, and has a common plenum 70 which communicates with the outlet 58 in manifold part 31 , which in turn is fixed into hole 20 of case part 2, and glued therein.

Ref 33 dual, mid audio range-high audio range, balanced armature speaker Ref 34 single low audio range balanced armature speaker

Ref 35 speaker holder, holds speakers (33, 34) in the ideal position and mates with supports (23) of case part (2). Referring to Figure 27-29, 31 , 32 these shows the speaker holder 35 in more detail, as comprising a rectangular frame 50 for receiving speaker 34, with a pair of lugs 52 for positioning speaker 34 within the frame. Lugs 52 also mate with lugs 23 (Figure 7) to secure the framework and speaker assembly to case part 2. A pair of spaced ears 54 extend either side of the speaker 33 to firmly seat the speaker 33. Lugs 56 position speaker 33 within ears 56.

Although not shown, a cross-over board may be provided secured to frame 50 and providing appropriate electrical connections to the speakers 33, 34.

Ref 36 Silicone injection hole on case part (2), this remains the same for both embodiments

Fig. 18 Shows internal supports of the cover part (30) of the second embodiment, wherein:

Ref 37 Supports which prevent movement of speaker assembly (33, 34, 35) by contact with the speaker (33).

Ref 38 Supports which prevent movement of speaker assembly (33, 34, 35) by contact with the speaker (34)

Fig. 19 is a Side view of cover part (30) with socket (4) installed, this shows how the socket sits once fixed in.

Fig. 20 Close up of supports (38)

Fig. 21 Close up of supports (37)

Fig. 22 Close up of socket (4) fixed into the supported area (25) of the cover (30).

Referring now to Figures 23 to 26, these show the first embodiment in assembled state, but with the case part (5) removed: Fig. 23 Side view of case part (2) with speaker (9) and speaker housing (10, 11). Transparency has been left on said case part to allow visibility of how said parts interact with one another

Fig. 24 Shows the speaker housing (10, 11) fully assembled, with the speaker (9) shown fixed onto said speaker housing in the correct orientation. Transparency of said speaker housing has been left on to show how the air chamber 40 is created.

Fig. 25 Top down view of earphone assembly. Cover part (5) has been left off for visibility of component layout

Fig. 26 Top down view of earphone assembly, but with a moulding 60 of silicone backfill having been injected through port 36. Shaded area represents the silicone backfill. The image shows that the interior of the earphone in its entirety is filled with the silicone material to ensure consistent results with each earphone. Again the cover part has been left off for visibility. It will be understood that the interior of case part 5 is also filled in its entirety with backfill, since the moulding is injected with the two case parts 2, 5 joined together.

Silicone backfill 60, in addition to improving the acoustics of the earphone, also served to firmly secure and accurately position the speaker within the outer shell.

Referring now to Figures 27 to 30, these show the second embodiment in assembled state, but with the case part (30) removed, wherein:

Fig. 27 Side view of case part (2) with speakers (33, 34), speaker holder (35) and speaker manifold (31 , 32). Transparency has been left on said case part to allow visibility of how said parts interact with one another

Fig. 28 Shows speakers (33, 34) assembled into the speaker holder (35) in the correct orientation. Said speaker holder has been designed to hold the drivers at the optimum position for both security within the assembly and for optimum sonic performance.

Fig. 29 Top down view of earphone assembly. Cover part (30) has been left off for visibility of component layout Fig. 30 Top down view of earphone assembly. Shaded area 60 represents the silicone backfill. The image shows that the interior of the earphone - in its entirety - is filled with the silicone material to ensure consistent sound and aesthetic results with each earphone. Again the cover part has been left off for visibility. It will be understood that the interior of case part 30 is also filled in its entirety with backfill, since the moulding is injected with the two case parts 2, 5 joined together.

Silicone backfill 60, in addition to improving the acoustics of the earphone, also serves to firmly secure and accurately position the speaker within the outer shell.

Referring now to Figure 35, this shows two perspective views of an alternative form of the air compartment housing for the first earphone embodiment of Figures 1 - 15, wherein the air compartment housing 62 completely encloses the speaker 9.