Open headphones

Abstract

A flexible arm is positioned between an acoustic module of the open headphone and a battery housing of the open headphone and configured to physically and electrically connect to the acoustic module and the battery housing. The flexible arm defines an original rest length and position between the acoustic module and the battery housing. The flexible arm includes a flexible printed circuit that extends throughout the original rest length of the flexible arm and includes a conductor configured to carry electrical energy between the acoustic module and the battery housing. A first interface structure is coupled to one of the acoustic module and the battery housing. A flexible material encases at least a portion of the flexible printed circuit and at least a portion of the first interface structure.

Description

[Technical field]

[0001] The present disclosure relates to over-the-ear headphones. [Background technology]

[0002] Open headphones typically emit sound close to the ear canal rather than inside it. Summary of the Invention [Means for solving the problem]

[0003] Aspects and examples are directed to open headphones having an acoustic module configured to be positioned within the concha of a user's outer ear. In some embodiments, the acoustic module includes an acoustic delivery portion configured to be positioned within the concha cavity. The acoustic module includes a housing that houses an acoustic transducer. The housing has a sound emission opening configured to emit sound generated by the acoustic transducer. The sound emission opening is configured to be positioned near the ear canal opening when the acoustic module is in place in the concha. The headphones also include a battery housing configured to be positioned behind the ear and a flexible arm positioned between the acoustic module and the battery housing and physically and electrically connecting the acoustic module and the battery housing. The flexible arm defines an original rest length and position between the acoustic module and the battery housing. The flexible arm includes a flexible printed circuit with conductors extending throughout the entire original rest length of the flexible arm and configured to carry electrical energy between the acoustic module and the battery housing. At one or both ends of the arm is an interface structure. The interface structure couples the arm to one or both of the battery housing and the acoustic module. The flexible material encases at least a portion of the flexible printed circuit and at least a portion of one or both interface structures. In some embodiments, the length of the flexible printed circuit within the flexible arm is longer than the original rest length of the flexible arm. Any excess length of the flexible printed circuit within the arm allows the flexible printed circuit to better accommodate tension or compression on the flexible arm when the flexible arm is bent from its original rest position.

[0004] All examples and features mentioned below can be combined in any technically possible manner.

[0005] In one aspect, a flexible arm is positioned between an acoustic module of the open headphone and a battery housing of the open headphone and configured to physically and electrically connect the acoustic module to the battery housing, the flexible arm including a flexible printed circuit that defines an original rest length and position between the acoustic module and the battery housing, the flexible arm including a conductor extending throughout the original rest length of the flexible arm and configured to carry electrical energy between the acoustic module and the battery housing. There is also a first interface structure coupled to one of the acoustic module and the battery housing. A flexible material encases at least a portion of the flexible printed circuit and at least a portion of the first interface structure.

[0006] Some embodiments include one of the above and / or the following features, or any combination thereof. In one embodiment, the flexible material is overmolded onto at least a portion of the flexible printed circuit and at least a portion of the first interface structure. In one embodiment, the flexible material includes an outer layer of the entire flexible arm. In some embodiments, the flexible arm also includes an internal support that interfaces with the flexible printed circuit within the flexible arm. In one embodiment, the internal support holds at least a portion of the flexible printed circuit within the flexible arm in a curved position such that the length of the flexible printed circuit within the flexible arm is longer than the original rest length of the flexible arm, thereby allowing the flexible printed circuit to better accommodate tension or compression on the flexible arm when the flexible arm is bent from its original rest position.

[0007] Some embodiments include one of the above and / or the following features, or any combination thereof. In some embodiments, the first interface structure comprises a relatively rigid structure defining at least one opening. In one embodiment, the flexible material is positioned in the opening of the relatively rigid structure. In one embodiment, the flexible printed circuit passes through the opening of the relatively rigid structure. In one embodiment, the relatively rigid structure defines two openings, and the flexible material is positioned in both openings. In one embodiment, the relatively rigid structure further comprises an enlarged end mechanically coupled to one of the acoustic module and the battery housing. In one embodiment, the relatively rigid structure defines a guide for the flexible printed circuit. In one embodiment, the relatively rigid structure further comprises an enlarged end mechanically coupled to one of the acoustic module and the battery housing.

[0008] Some embodiments include one of the above and / or the following features, or any combination thereof. In some embodiments, the flexible arm further includes a second interface structure coupled to the other of the acoustic module and the battery housing. In one embodiment, the first interface structure is coupled to the battery housing and the second interface structure is coupled to the acoustic module. In one embodiment, the first interface structure defines a single opening filled with the flexible material and further defines a guide for the flexible printed circuit, and the first interface structure is bonded to the battery housing. In one embodiment, the second interface structure defines at least one opening, the flexible printed circuit passes through the opening, and the flexible material is positioned in the at least one opening. In one embodiment, the acoustic module comprises two separate parts snapped together around the second interface structure. In one embodiment, the original rest position of the flexible arm is along a curved axis that defines a simple open curve.

[0009] In another aspect, a flexible arm is positioned between an acoustic module of an open headphone and a battery housing of the open headphone and configured to physically and electrically connect the acoustic module to the battery housing, the flexible arm including a flexible printed circuit that defines an original rest length and position between the acoustic module and the battery housing and includes a conductor that extends throughout the original rest length of the flexible arm and is configured to carry electrical energy between the acoustic module and the battery housing, a first interface structure coupled to the battery housing, a second interface structure coupled to the acoustic module, and a flexible material that encases at least a portion of the flexible printed circuit and at least a portion of the first and second interface structures. The flexible material includes an outer layer of the entire flexible arm. The first interface structure defines a single opening filled with the flexible material and further defines a guide for the flexible printed circuit. The first interface structure is bonded to the battery housing. The second interface structure defines at least one opening. The flexible printed circuit passes through the opening and the flexible material is positioned in the at least one opening.

[0010] Some embodiments include one of the above and / or the following features, or any combination thereof: In one embodiment, the flexible arm further includes an internal support that interfaces with the flexible printed circuit within the flexible arm, the internal support holding at least a portion of the flexible printed circuit within the flexible arm in a curved position such that the length of the flexible printed circuit within the flexible arm is longer than an original rest length of the flexible arm, such that the flexible printed circuit can better accommodate tension or compression on the flexible arm when the flexible arm is bent from its original rest position.

[0011] Various aspects of at least one example are discussed below with reference to the accompanying drawings, which are not intended to be drawn to scale. These drawings are included to provide illustration and further understanding of the various aspects and examples, and are incorporated in and constitute a part of this specification, but are not intended as a definition of the limitations of the invention. In the drawings, identical or nearly identical components shown in various figures may be labeled with similar letters or numerals. For clarity, every component may not necessarily be labeled in every figure. [Brief description of the drawings]

[0012] [Figure 1A] FIG. 2 is a side view of the open-type headphones. [Figure 1B] FIG. 2 is a rear view of the open-type headphones. [Figure 1C] FIG. 1C is a cross-sectional view taken along line 1C-1C of FIG. 1B. [Figure 2A] FIG. 13 is a front perspective view of an interface structure for a flexible arm. [Figure 2B] FIG. 13 is a rear view of an interface structure for a flexible arm. [Diagram 3] FIG. 2C is a perspective view of the interface structure of FIGS. 2A and 2B engaged with a battery housing of an open-type headphone. [Figure 4] FIG. 13 is a rear perspective view of another interface structure for a flexible arm. [Diagram 5] FIG. 5 is a perspective view of the interface structure of FIG. 4 engaged with an acoustic module of an open headphone. [Figure 6A] FIG. 5 is a partial view of a flexible printed circuit of a flexible arm engaged with the interface structure of FIGS. 2A, 2B, and 4. [Figure 6B] 1 illustrates a partially assembled open headphone with flexible arms. [Figure 7A] FIG. 13 is a front perspective view of an internal support for the flexible arm. [Figure 7B]FIG. 13 is a rear view of the internal support for the flexible arm. [Figure 8] FIG. 7C is a partial view of a flexible printed circuit of a flexible arm engaged with the internal support of FIGS. 7A and 7B. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Open headphones worn on the ears must provide high quality sound, be stable on the ears, be comfortable for long-term wear, be unobtrusive, and look stylish. These objectives can be difficult to achieve because they have been considered mutually exclusive in some respects. For example, stability typically leads to clamping to the outer ear, which can feel uncomfortable for long-term wear and may not look stylish. Also, for high quality sound, sound must be delivered near the ear canal, not in it, which means that the headphone structure must overlap the ear and can be clearly seen by others. Also, for best sound quality, sound should be delivered near the ear canal opening, not in it.

[0014] The embodiments of the open-type headphones discussed herein are not limited in their application to the details of construction and the arrangement of components described in the following description or illustrated in the accompanying drawings. The headphones can be implemented in other embodiments and can be practiced or performed in various ways. The specific embodiments are provided herein for illustrative purposes only and are not intended to be limiting. In particular, functions, components, elements, and features discussed in connection with any one or more embodiments are not intended to be excluded from a similar role in any other embodiment.

[0015] Examples disclosed herein can be combined with other examples in any manner consistent with at least one of the principles disclosed herein, and further, references to "an example," "some examples," "an alternate example," "various examples," "one example," and the like are not necessarily mutually exclusive and are intended to indicate that a particular feature, structure, or characteristic being described may be included in at least one example. Appearances of such terms in this specification do not necessarily all refer to the same example.

[0016] Additionally, the phrases and terms used herein are for descriptive purposes only and should not be considered limiting. Any reference to an example, component, element, act, or function of the headphones referred to in the singular herein may also include embodiments including the plural, and any reference to any example, component, element, act, or function herein in the plural may also include examples including only the singular. Thus, singular or plural references are not intended to limit the systems or methods of the present disclosure, their components, acts, or elements. The use of "including," "comprising," "having," "containing," "involving," and variations thereof herein are meant to include the items listed below and their equivalents, as well as other items. References to "or" may be construed as inclusive, such that all terms described with "or" can refer to either the single, the plural, and all terms of the described term.

[0017] In some embodiments herein, the open headphone includes a flexible arm positioned between an acoustic module and a battery housing of the headphone and configured to physically and electrically connect to the acoustic module and the battery housing. The flexible arm defines an original rest length and position between the acoustic module and the battery housing. The flexible arm includes a flexible printed circuit extending across the entire original rest length of the flexible arm. The flexible printed circuit includes one or more conductors that carry electrical energy between the acoustic module and the battery housing. An interface structure is coupled to the acoustic module or the battery housing. A flexible material encases at least a portion of the flexible printed circuit and at least a portion of the interface structure. In some embodiments, the length of the flexible printed circuit within the flexible arm is longer than the original rest length of the flexible arm. The flexible printed circuit can thus better accommodate tension or compression to the flexible arm when the flexible arm is bent from its original rest position.

[0018] In some embodiments, the original rest position of the flexible arm is along a curved axis. In one embodiment, the curved axis defines a simple open curve. In one embodiment, the curved axis is generally "C" shaped. In one embodiment, the curved axis bisects the flexible arm, and different portions of the first surface of the flexible printed circuit are on different sides of the curved axis. In one embodiment, the flexible printed circuit defines at least one simple open curve along the length of the flexible printed circuit within the flexible arm. In one embodiment, the flexible printed circuit defines a plurality of both upward and downward simple open curves along the length of the flexible printed circuit within the flexible arm. In one embodiment, each downward simple open curve is adjacent to one or more upward simple open curves.

[0019] FIG. 1A is a side view of the open-type headphones 10, FIG. 1B is a rear view, and FIG. 1C is a cross-sectional view taken along line 1C-1C of FIG. 1B. The headphones 10 are configured to be worn on a user's ear such that a distal sound delivery end 17 of the headphones' acoustic module 12 is positioned within the ear's concha and a battery housing 14 is positioned behind the ear. A flexible arm 20 is configured to pass over the helix, antihelix, and / or the outer upper portion of the earlobe of the ear. The arm 20 has an original or rest position and length illustrated in FIGS. 1A-1C. In some embodiments, the original position defines a generally "C" shape as shown in these figures. The arm 20 is configured to flex at least along the length of the arm, thereby allowing a slight increase in the space between the acoustic module 12 and the battery housing 14. This allows the headphones 10 to be removed from the ear without having to be forced over the outer ear, and also provides a light clamping force on the ear to help hold the headphones 10 in place over the ear as the user's head moves. Note that FIGS. 1A-1C illustrate some interference between the acoustic module 12 and the battery housing 14. However, in most embodiments, there is actually a space between the two, as disclosed, for example, in the patents incorporated by reference. In some embodiments, this interference is modeled such that the arm 20 would try to "rest" in this position if it were molded into this shape. This modeling helps create some preload on the arm.

[0020] Electrical signals need to be carried through the arm 20. In some embodiments, the electrical signals include or comprise power from the battery 15 in the battery housing 14 to any electrical circuitry and components in the acoustic module 12 and the acoustic transducer 13. In some embodiments, the electrical signals also include audio signals from wireless receiving and processing circuitry (not shown) that may be located in one or more of the arm 20, the battery housing 14, and the acoustic module 12. In some embodiments, these electrical signals are carried by conductors in the flexible printed circuit 80. The flexible printed circuit needs to be able to flex when the arm 20 flexes, but at the same time needs to carry the necessary electrical signals.

[0021] The flexible printed circuit 80 carries power from a battery (not shown) held by molded-in ribs 15 to data receiving and processing circuitry on the printed circuit board 21. Power and audio signals are provided from the board 21 to the transducer 13. The transducer 13 creates sound pressure in the front acoustic cavity 23 and the rear acoustic cavity 25. Openings / ports (not shown) in the acoustic module housing 27 are paths for sound to escape the housing 27. The flexible printed circuit 80, arm interface structures 50 and 70, and flexible overmold material 95 are described further below.

[0022] Additional details of open headphones, including but not limited to details of their construction, operation, and acoustic performance, are disclosed in U.S. Patent No. 11,140,469, the entire disclosure of which is incorporated herein by reference for all purposes. Aspects of the present open headphones disclosed in this patent will not be described further herein.

[0023] In some embodiments, the flexible arm 20 includes one or more interface structures. The interface structures are configured to mechanically couple the arm to one or both of the battery housing and the acoustic module. In some embodiments, the interface structures are relatively rigid but have some malleability. The interface structures can be made of engineering plastics such as nylon or acrylonitrile butadiene styrene (ABS), or from rubber or rubber-like materials. In some embodiments, the interface structures are made by injection molding, machining, stamping, or 3D printing. In some embodiments, the interface structures are a single piece. The interface structures help to hold the arm in its curved rest position and provide stiffening reinforcement to the arm. In some embodiments, the interface structures also help to anchor a relatively soft overmold that covers the entire arm. In some embodiments, the overmold also covers at least a portion of the battery housing.

[0024] 2A and 2B illustrate a first interface structure 50. The interface structure 50 is a one-piece molded plastic part that defines a terminal enlarged portion 52, a middle enlarged portion 54, and an opening 56. As described further below, the interface structure 50 is configured to couple the flexible arm 20 to the battery housing 14, to help support and guide the flexible printed circuit, and to anchor the overmold. As shown in FIG. 3, the terminal enlarged portion 52 is configured to be coupled to the battery housing 14. In some embodiments, the portion 52 is received within a complementary shaped cavity (not shown) in the battery housing 14, and / or the battery housing 14 is made from two (or more) pieces snapped or otherwise mated together around the portion 52. In some embodiments, an adhesive (such as a pressure sensitive adhesive) is used to more permanently attach the interface structure 50 to the battery housing 14.

[0025] The interface structure 50 defines a guide 58 for the flexible printed circuit. The guide 58 has approximately the same width and thickness as the flexible printed circuit so that the flexible printed circuit is guided through the slot 55 into the battery housing. The guide 58 helps to properly center, align, and support the flexible printed circuit. As shown in FIG. 2B, the guide 58 includes a flat surface created by the gap on the backsides of the portions 52 and 54. The portion 52 is defined by separated ends 52a and 52b. The portion 54 is defined by separated ends 54a and 54b. The guide 58 is defined in part by the space between the ends 52a and 52b and the space between the ends 54a and 54b.

[0026] The opening 56 in the interface structure 50 is located outside and near the battery housing 14. When the arm structure and battery housing are overmolded with silicone, the silicone fills the opening 56. This helps bond the silicone to the interface structure 50 and create a flexible arm 20 that is reinforced and sealed at the end that contacts the battery housing 14. In some embodiments, a flexible printed circuit passes through the opening 56, which further helps guide and support the flexible printed circuit.

[0027] A second interface structure 70 (FIG. 4) couples the flexible arm 20 to the acoustic module 12. The interface structure 70 is a one-piece molded plastic part that defines an end flared portion 72, an intermediate flared portion 74 defined by separated ends 74a and 74b, and an opening 76. The interface structure 70 is configured to couple the flexible arm 20 to the acoustic module 12, to help support and guide the flexible printed circuit, and to anchor the overmold. As shown in FIG. 5, the end flared portion 72 is configured to be coupled to the acoustic module 12. In some embodiments, the portion 72 is received within a complementary shaped cavity (not shown) in the acoustic module 12, and / or the acoustic module 12 is made from two (or more) pieces snapped or otherwise mated together around the portion 72. In some embodiments, an adhesive (such as a pressure sensitive adhesive) is used to more permanently attach the interface structure 70 to the acoustic module 12.

[0028] The interface structure 70 defines a guide 75 for the flexible printed circuit. The guide 75 has a width and thickness approximately the same as the width and thickness of the flexible printed circuit so that the flexible printed circuit is guided through a slot (not shown) into the acoustic module. The guide 75 helps to properly center, align, and support the flexible printed circuit. As shown in FIG. 4, the guide 75 includes a flat surface created by the gap between ends 74a and 74b.

[0029] The opening 76 in the interface structure 70 is positioned outside and near the acoustic module 12. When the arm structure (and in some cases the portion of the acoustic module 12 adjacent the interface structure 70) is overmolded with silicone, the silicone fills the opening 76. This helps bond the silicone to the interface structure 70 and create a flexible arm 20 that is reinforced and sealed at the end that contacts the acoustic module 12. In some embodiments (such as that shown in FIG. 6A), the flexible printed circuit passes through the opening 76, which further helps guide and support the flexible printed circuit.

[0030] FIG. 6A illustrates the manner in which the flexible printed circuit 80 interfaces with the interface structure 50 and the interface structure 70. A first end 82 of the flexible printed circuit is configured to interface with a printed circuit board connected to two terminals of a battery (not shown) in the battery housing 14, while a second end 84 is configured to interface with a printed circuit board (such as the printed circuit board 21 in FIG. 1C) in the acoustic module 12. To accommodate the flexing of the arm 20 while reducing stress on the flexible printed circuit 80, the flexible printed circuit 80 can have a length at the arm 20 that is longer than the nominal rest length of the arm 20. The additional length can be achieved by one or more curves in the flexible printed circuit that are held within the flexible arm 20. Adjacent upward and downward simple open curves 90, 91, 92, and 93 are shown. In some embodiments, one or more of the curves are held in place by internal supports within the arm. In some embodiments, the internal support includes one or more of interface structure 50, interface structure 70, and / or internal support 100 (FIGS. 7A and 7B). In this example, a portion 88 of flexible printed circuit 80 is threaded through opening 76 in interface structure 70.

[0031] In some embodiments herein, the overmold surrounds and encases the flexible printed circuit along at least most, and preferably all, of the original resting length of the flexible arm, as well as some, and preferably all, of any internal supports and interface structures. For example, flexible arm 96 (FIG. 6B) includes an overmold 95 that completely covers the flexible printed circuit 80 of arm 96. FIG. 6B illustrates a flexible arm as partially depicted in FIG. 6A. In one embodiment, the overmold 95 is a silicone material. The overmold 95 includes the outer layer of arm 96 and also covers some or all of the battery housing member 94, thus also defining the outer layer of some or all of the battery housing 14. The overmold 95 can be realized using insert molding techniques. The enlarged end 97 represents a portion of the overmold that overlies or abuts the acoustic module, not shown in this figure. Also shown in this view is the enlarged end 72 of interface structure 70 which serves to help mechanically couple arm 96 to the acoustic module as well as provide stress relief for flexible printed circuit 80. Overmold 95 also helps increase the environmental stability of the flexible arm by sealing the openings between portions 50 and 70 and the battery housing and acoustic module while retaining the flexibility of the arm.

[0032] Different internal supports 100 are illustrated in Figures 7A, 7B, and 8. The internal support 100 can be made by injection molding, machining, or stamping. In some embodiments, the internal support 100 is a single member. The internal support 100 includes a body 106 having openings that make or define struts, e.g., struts 107 and openings 108, 109, and 110. The enlarged ends 102 and 104 (functioning like interface structures 50 and 70) are configured to be mechanically coupled to one of the battery housing and the acoustic module, such as by interference fit and / or adhesive. Such internal supports help provide the arms with the necessary level of stiffness to keep the open headphones securely on the ears without being painfully tight. Different structural designs can provide different levels of bending stiffness and torsional resistance. Examples include, but are not limited to, lattice designs, perforated designs, and slotted designs. Alternatively, the internal support can be made from spring steel or Nitinol wire.

[0033] The flexible printed circuit can pass through one or more openings in the support, but is not required. For example, as shown in FIG. 8, a portion 89 of the flexible printed circuit 80 is threaded through openings 108 and 109, which helps provide stress relief to the flexible printed circuit 80. In some embodiments, the arm is completed by overmolding a flexible material that encases all or substantially all of the internal support 100. The overmolding fills, or at least partially or substantially fills, the openings in the internal support 100, thus helping to anchor the internal support 100 within the arm. In some embodiments, as shown in FIG. 8 and similar to the guiding features illustrated in FIGS. 2B, 4, and 6A, the internal support 100 also acts as a guide for the flexible printed circuit 80, which can pass through the back surface of the internal support 100.

[0034] Having described several aspects of at least one embodiment, it will be appreciated that various changes, modifications, and improvements will readily occur to those skilled in the art. Such changes, modifications, and improvements are intended to be part of this disclosure and within the scope of the invention. Accordingly, the foregoing description and drawings are by way of example only, with the scope of the invention to be determined from proper construction of the appended claims and their equivalents. [Explanation of symbols]

[0035] 10 Open headphones 12 Acoustic Module 13 Acoustic Transducer 14 Battery Housing 15 Battery 17 Distal Sound Delivery End 20 Flexible Arm 21 Printed Circuit Board 23 Forward acoustic cavity 25 Rear acoustic cavity 27 Acoustic module housing 50 First interface structure 52 Terminal expansion part 52a, 52b end 54 Intermediate enlarged section 54a, 54b end 55 Slots 56 Opening 58 Guide 70 Secondary Interface Structure 72 Terminal expansion part 74 Intermediate enlarged section 74a, 74b end 75 Guide 76 Opening 80 Flexible Printed Circuits 82 First end 84 Second End 88 part 89 part 90, 91, 92, 93 Simple open curves 94 Battery housing parts 95 Flexible Overmolding Materials 96 Flexible Arm 97 Enlarged End 100 Internal support 102 Enlarged end 104 Enlarged end 106 Main Unit 107 Strut 108, 109, 110 Openings

Claims

1. a flexible arm positioned between an acoustic module of an open headphone and a battery housing of the open headphone and configured to physically and electrically connect the acoustic module to the battery housing, the flexible arm defining an original rest length and position between the acoustic module and the battery housing; a flexible printed circuit including conductors extending throughout the original resting length of the flexible arm and configured to carry electrical energy between the acoustic module and the battery housing; a first interface structure coupled to one of the acoustic module and the battery housing; a flexible material encasing at least a portion of the flexible printed circuit and at least a portion of the first interface structure.

2. The flexible arm of claim 1 , wherein the flexible material is overmolded onto at least a portion of the flexible printed circuit and at least a portion of the first interface structure.

3. The flexible arm of claim 1 , wherein the flexible material comprises an outer layer of the entire flexible arm.

4. The flexible arm of claim 1 , wherein the flexible arm further comprises an internal support that interfaces with the flexible printed circuit within the flexible arm.

5. 5. The flexible arm of claim 4, wherein the internal support holds at least a portion of the flexible printed circuit within the flexible arm in a curved position such that a length of the flexible printed circuit within the flexible arm is longer than the original rest length of the flexible arm, thereby allowing the flexible printed circuit to better accommodate tension or compression on the flexible arm when the flexible arm is bent from the original rest position of the flexible arm.

6. The flexible arm of claim 1 , wherein the first interface structure comprises a relatively rigid structure defining at least one opening.

7. The flexible arm of claim 6 , wherein the flexible material is positioned in an opening in the relatively rigid structure.

8. The flexible arm of claim 6 , wherein the flexible printed circuit passes through an opening in the relatively rigid structure.

9. The flexible arm of claim 8 , wherein the relatively rigid structure defines two openings, and the flexible material is positioned in both openings.

10. The flexible arm of claim 8 , wherein the relatively rigid structure further comprises an enlarged end mechanically coupled to one of the acoustic module and the battery housing.

11. The flexible arm of claim 6 , wherein the relatively rigid structure defines a guide for the flexible printed circuit.

12. The flexible arm of claim 11 , wherein the relatively rigid structure further comprises an enlarged end mechanically coupled to one of the acoustic module and the battery housing.

13. The flexible arm of claim 1 , further comprising a second interface structure coupled to the other of the acoustic module and the battery housing.

14. The flexible arm of claim 13 , wherein the first interface structure is coupled to the battery housing and the second interface structure is coupled to the acoustic module.

15. 15. The flexible arm of claim 14, wherein the first interface structure defines a single opening filled with the flexible material and further defines a guide for the flexible printed circuit, the first interface structure being adhered to the battery housing.

16. 16. The flexible arm of claim 15, wherein the second interface structure defines at least one opening, the flexible printed circuit passing through the opening, and the flexible material positioned in the at least one opening.

17. The flexible arm of claim 16 , wherein the acoustic module comprises two separate parts that are snapped together around the second interface structure.

18. The flexible arm of claim 1 , wherein the original rest position of the flexible arm is along a curved axis that defines a simple open curve.

19. a flexible arm positioned between an acoustic module of an open headphone and a battery housing of the open headphone and configured to physically and electrically connect the acoustic module to the battery housing, the flexible arm defining an original rest length and position between the acoustic module and the battery housing; a flexible printed circuit including conductors extending throughout the original resting length of the flexible arm and configured to carry electrical energy between the acoustic module and the battery housing; a first interface structure coupled to the battery housing; a second interface structure coupled to the acoustic module; a flexible material encasing at least a portion of the flexible printed circuit and at least a portion of the first and second interface structures, the flexible material including an outer layer of the entire flexible arm; the first interface structure defines a single opening filled with the flexible material and further defines a guide for the flexible printed circuit, the first interface structure being adhered to the battery housing; A flexible arm, the second interface structure defining at least one opening, the flexible printed circuit passing through the opening, and the flexible material positioned in the at least one opening.

20. 20. The flexible arm of claim 19, further comprising an internal support interfacing with the flexible printed circuit within the flexible arm, the internal support holding at least a portion of the flexible printed circuit within the flexible arm in a curved position such that the length of the flexible printed circuit within the flexible arm is longer than the original rest length of the flexible arm so that the flexible printed circuit can better accommodate tension or compression on the flexible arm when the flexible arm is bent from the original rest position of the flexible arm.

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