Flexible arms for open headphones

Abstract

A flexible arm (140) is configured to be positioned between an acoustic module (12) of an open headphone (10) and a battery housing (14) of the open headphone and to physically and electrically connect to the acoustic module (12) and the battery housing (14). The flexible arm (140) defines an original rest length and position between the acoustic module (12) and the battery housing (14). The flexible arm (140) includes a flexible printed circuit (142) that extends throughout the original rest length of the flexible arm (140) and includes a conductor configured to carry electrical energy between the acoustic module (12) and the battery housing (14), and a flexible material (144) that encapsulates at least a portion of the flexible printed circuit (142). The length of the flexible printed circuit (142) within the flexible arm (140) is longer than the original rest length of the flexible arm. The flexible printed circuit (142) can therefore better accommodate tension or compression on the flexible arm (140) when the flexible arm is bent from its original rest position.

Description

[Technical Field]

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

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

[0003] Aspects and embodiments 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 is 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 extending throughout the original rest length of the flexible arm and including conductors configured to carry electrical energy between the acoustic module and the battery housing. A flexible material encases at least a portion of the flexible printed circuit. The length of the flexible printed circuit within the flexible arm is longer than the original rest length of the flexible arm. The extra 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 open headphones and a battery housing of the open headphones 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 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; and a flexible material that encases at least a portion of the flexible printed circuit. 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 therefore better accommodate tension or compression on the flexible arm when the flexible arm is bent from its original rest position.

[0006] Some embodiments include one of the above and / or below features, or any combination thereof. In embodiments, the flexible printed circuit defines at least one simple open curve within the flexible arm along the length of the flexible printed circuit. In embodiments, the flexible printed circuit defines both a plurality of upward and downward simple open curves along the length of the flexible printed circuit within the flexible arm. In embodiments, each downward simple open curve of the flexible printed circuit is adjacent to one or more of the upward simple open curves. In some embodiments, the original rest position of the flexible arm is along a bending axis. In embodiments, the bending axis of the flexible arm defines the simple open curve. In embodiments, the bending axis is generally "C" shaped. In embodiments, the bending axis bisects the flexible arm, and different portions of the first surface of the flexible printed circuit are on different sides of the bending axis.

[0007] Some embodiments include one of the above and / or below features, or any combination thereof. In some embodiments, the flexible material comprises two mating members each defining a series of simple open curves along the original resting length of the flexible arm. In embodiments, the simple open curves of the two mating members are complementary. In embodiments, the two mating members each define a wavy mating surface, with a protrusion of one member aligned with and mating with a recess of the other member, and the flexible printed circuit positioned between the mating surfaces of the two mating members. In embodiments, the flexible arm also includes an overmold surrounding the flexible material along at least a majority of the original resting length of the flexible arm. In embodiments, the overmold further covers at least a portion of the battery housing.

[0008] Some embodiments include one of the above and / or below features, or any combination thereof. In some embodiments, the flexible printed circuit defines one or more open curves within the flexible arm along the length of the flexible printed circuit. In embodiments, the one or more open curves are simple open curves. In embodiments, the flexible arm also includes a flexible printed circuit stress relief member proximate the flexible material. The flexible printed circuit stress relief member defines an opening through which the flexible printed circuit is threaded. In embodiments, the flexible printed circuit defines an open slot along a portion of the length of the flexible printed circuit within the flexible arm to accommodate twisting of the flexible printed circuit about the length of the flexible printed circuit.

[0009] In another aspect, a flexible arm is positioned between an acoustic module of open headphones and a battery housing of the open headphones 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 original rest position of the flexible arm being generally along a "C"-shaped curved axis, the flexible printed circuit including conductors that extend throughout the original rest length of the flexible arm and are configured to carry electrical energy between the acoustic module and the battery housing; and a flexible material that encases at least a portion of the flexible printed circuit. The flexible printed circuit defines at least one simple open curve along a length of the flexible printed circuit within the flexible arm such that the length of the flexible printed circuit within the flexible arm is longer than the original rest length of the flexible arm. This 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.

[0010] Some embodiments include one or any combination of the above and / or below features. In embodiments, 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, each downward simple open curve of the flexible printed circuit adjacent to an upward simple open curve. In embodiments, the flexible arm also includes a flexible printed circuit stress relief member proximate the flexible material. The flexible printed circuit stress relief member defines an opening through which the flexible printed circuit is threaded.

[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 a further understanding of various aspects and examples, and are incorporated into and constitute a part of this specification, but are not intended as a definition of the limits of the invention. In the drawings, identical or nearly identical components shown in various figures may be labeled with like letters or numerals. For clarity, not every component may be labeled in every figure. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view of an open-type headphone. [Figure 2A] 2A and 2B are perspective and side exploded views, respectively, of a portion of a flexible arm for open headphones. [Figure 2B] 2B are perspective and side exploded views, respectively, of a portion of a flexible arm for open headphones. [Figure 2C] FIG. 2C is an assembled view of the partially flexible arm of FIGS. 2A and 2B. [Figure 2D] FIG. 2D illustrates a portion of the flexible arm partially depicted in FIGS. 2A-2C. [Figure 3] FIG. 3 illustrates a partially assembled open headphone with flexible arms. [Figure 4] FIG. 4 illustrates a flexible printed circuit partially encased in a flexible material for a flexible arm. [Figure 5A] FIG. 5A is a schematic diagram of an embodiment of a flexible arm. [Figure 5B] FIG. 5B illustrates the stress relief member of the flexible arm of FIG. 5A. [Figure 6] FIG. 6 partially illustrates a flexible printed circuit for the flexible arm. DETAILED DESCRIPTION OF THE INVENTION

[0013] Open-ear headphones must provide high-quality sound, be stable on the ear, be comfortable for extended wear, be discreet, and be 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 be uncomfortable for extended wear and may not be stylish. Also, for high-quality sound, sound must be delivered near the ear canal, not in it, which means the headphone structure must be placed over the ear and therefore be clearly visible to others. Also, for best sound quality, sound should be delivered near the ear canal opening, not in it.

[0014] The open-back headphone embodiments discussed herein are not limited in their application to the details of construction and arrangements of components set forth in the following description or illustrated in the accompanying drawings. The headphones may be implemented in other embodiments and practiced or carried out in various ways. 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 embodiments.

[0015] Examples disclosed herein may 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," etc. are not necessarily mutually exclusive and are intended to indicate that a particular feature, structure, or characteristic described may be included in at least one example. Appearances of such terms herein do not necessarily all refer to the same example.

[0016] Additionally, the phraseology and terminology used herein are for descriptive purposes only and should not be considered limiting. Any reference herein to an example, component, element, act, or function of headphones in the singular may also encompass embodiments that include the plural, and any reference herein to any example, component, element, act, or function in the plural may also encompass examples that include only the singular. Therefore, singular or plural references are not intended to limit the systems or methods of the present disclosure, their components, acts, or elements. The use herein of "including," "comprising," "having," "containing," "involving," and variations thereof, is meant to encompass 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" refer to either the singular, the plural, and all terms of the described term.

[0017] In some embodiments herein, the open-type headphones include a flexible arm positioned between an acoustic module and a battery housing and configured to physically and electrically connect to the acoustic module and the battery housing. The flexible arm defines an original resting length and position between the acoustic module and the battery housing. The flexible arm includes a flexible printed circuit extending over the entire original resting 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. A flexible material encases at least a portion of the flexible printed circuit. The length of the flexible printed circuit within the flexible arm is longer than the original resting length of the flexible arm. The flexible printed circuit can therefore better accommodate tension or compression on the flexible arm when the flexible arm is bent from its original resting position.

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

[0019] In some embodiments, the flexible material includes two mating members each defining a series of simple open curves along the original, resting length of the flexible arm. In embodiments, the simple open curves of the two mating members are complementary. In embodiments, the two mating members each define a wavy mating surface, with a protrusion of one member aligned with and mating with a recess of the other member, and the flexible printed circuit positioned between the mating surfaces of the two mating members. In embodiments, the flexible arm also includes an overmold surrounding the flexible material along at least a majority, and preferably all, of the original, resting length of the flexible arm. In embodiments, the overmold further covers at least a portion, and preferably all, of the battery housing.

[0020] In some embodiments, the flexible printed circuit defines one or more open curves within the flexible arm along the length of the flexible printed circuit. In embodiments, the one or more open curves are simple open curves. In embodiments, the flexible arm also includes a flexible printed circuit stress relief member adjacent to the flexible material. The stress relief member defines an opening through which the flexible printed circuit is threaded. In embodiments, the flexible printed circuit defines an open slot along a portion of the length of the flexible printed circuit within the flexible arm to accommodate twisting of the flexible printed circuit about the length of the flexible printed circuit.

[0021] In another embodiment herein, open-type headphones include a flexible arm positioned between an acoustic module and a battery housing, physically and electrically connecting the acoustic module to the battery housing. The flexible arm defines an original rest length and position between the acoustic module and the battery housing. The original rest position of the flexible arm is generally along a curved axis of the "C" shape. The arm includes a flexible printed circuit extending across the entire original rest length of the arm. The flexible printed circuit includes one or more conductors that carry electrical energy between the acoustic module and the battery housing. A flexible material encases at least a portion of the flexible printed circuit. The flexible printed circuit defines at least one simple open curve along the length of the flexible printed circuit within the flexible arm such that the length of the flexible printed circuit within the flexible arm is longer than the original rest length of the flexible arm. This 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.

[0022] In an 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, each downward simple open curve being adjacent to an upward simple open curve. In an embodiment, the flexible arm also includes a flexible printed circuit stress relief member adjacent to the flexible material. The stress relief member defines an opening through which the flexible printed circuit is threaded.

[0023] FIG. 1 is a perspective view of open-type headphones 10. The headphones 10 are configured to be worn on a user's ear such that the headphones' acoustic module 12 is positioned within the concha of the ear and the battery housing 14 is positioned behind the ear. A flexible arm 20 is configured to pass over the outer upper portion of the ear's helix, antihelix, and / or lobule. The arm 20 has an original or resting position and length, as illustrated in FIG. 1. In some embodiments, the original position defines a general "C" shape, as shown in FIG. 1. The arm 20 is configured to flex along at least its length, thereby slightly increasing the space between the acoustic module 12 and the battery housing 14. This allows the headphones 10 to be put on and taken off from the ear without having to be pushed onto the outer ear, and also provides a light clamping force on the ear as the user's head moves, helping to hold the headphones 10 in place on the ear. Electrical signals need to be carried through the arm 20. In some embodiments, the electrical signals include power from a battery (not shown) in the battery housing 14 to an acoustic transducer (not shown) in the acoustic module 12, and audio signals from wireless receiving and processing circuitry (not shown) that may be located in one or both of the arm 20 and the battery housing 14. In some embodiments, these electrical signals are carried by conductors in a flexible printed circuit. The flexible printed circuit needs to be able to flex when the arm 20 flexes, yet at the same time, it needs to carry the necessary electrical signals. Flexible printed circuits are well known in the electrical / electronics arts and therefore will not be described further herein.

[0024] 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. The aspects of the present open headphones disclosed in this patent will not be further described herein.

[0025] 2A and 2B are perspective and side exploded views of a portion 30 of a flexible arm for open-type headphones. The portion 30 includes a flexible printed circuit 31, which itself includes one or more conductors (not shown). In some embodiments, the flexible printed circuit 31 extends throughout the entire original, resting length of the flexible arm in which the flexible printed circuit is used. A flexible material 40 encases at least a portion of the flexible printed circuit 31. In this embodiment, the flexible material 40 includes separate mating portions 42 and 44. In some embodiments, the portions 42 and 44 are made from a flexible material such as silicone. To accommodate the flexure of the arm in which the portion 30 is used, the length of the flexible printed circuit within the flexible arm is longer than the original, resting 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 its original, resting position. In this embodiment, portions 42 and 44 each define a series of alternating recesses and protrusions that are configured to mate when portions 42 and 44 are assembled together, as depicted in FIG. 2C.

[0026] FIG. 2C is an assembled view of the partial flexible arm of FIGS. 2A and 2B. The result is a wave or roughly sinusoidal shape imprinted on the flexible printed circuit. In this example, convex and concave adjacent simple open curves 52, 54, 56, 58, and 60 are imprinted on the flexible printed circuit 31. These curves are partially on either side of the arm's central longitudinal axis 33. One or more of the curves achieve a conductor length that is longer than the original resting length of the flexible arm in which the portion 30 is used. When the arm is bent, the extra length accommodates the bend with less stress or bending on the conductors of the flexible printed circuit. Because the conductors of the flexible printed circuit are typically metal (e.g., copper traces) and can fatigue and break when flexed or bent, the extra length helps the flexible printed circuit withstand repeated insertion and removal of open headphones.

[0027] In embodiments herein, the longer length of the flexible printed circuit 31 is achieved by configuring the flexible printed circuit 31 to define one or more open curves along the length of the flexible printed circuit within the flexible arm. In some embodiments, the one or more open curves are simple open curves. In some embodiments, the original rest position of the flexible arm is along a bending axis, and the flexible printed circuit defines at least one simple open curve along the length of the flexible printed circuit within the flexible arm. In some embodiments, the bending axis of the arm defines a simple open curve. In embodiments, the bending axis is generally "C" shaped. In embodiments, the bending axis bisects the flexible arm, and different portions of the first surface (e.g., top or bottom) of the flexible printed circuit are on different sides of the bending axis. In embodiments, the flexible printed circuit defines both a plurality of upward and downward simple open curves along the length of the flexible printed circuit within the flexible arm. In embodiments, each downward simple open curve of the flexible printed circuit is adjacent to one or more of the upward simple open curves.

[0028] In some embodiments, the flexible material comprises two mating members each defining a series of simple open curves along the original, resting length of the flexible arm. In embodiments, the simple open curves of the two mating members are complementary. In embodiments, the two mating members each define a wavy mating surface, with a protrusion of one member aligned with and mating with a recess of the other member, and the flexible printed circuit positioned between the mating surfaces of the two mating members.

[0029] In some embodiments herein, the overmold surrounds the flexible material encasing the flexible printed circuit along at least a majority of the original, resting length of the flexible arm. For example, flexible arm portion 70 of FIG. 2D includes an overmold 72 that completely covers most or all of flexible material 40. FIG. 2D illustrates more of the flexible arm partially depicted in FIGS. 2A-2C. In an embodiment, overmold 72 is a silicone material. Overmold 72 also serves to increase the environmental stability of the flexible arm by sealing openings between portions 42 and 44 and / or at the ends of material 40 while maintaining the flexibility of the arm.

[0030] FIG. 3 illustrates a partially assembled open-type headphone having a flexible arm 100. The arm 100 is connected to the housing member 80 of the battery housing 14. An overmold 90 includes the outer layer of the arm 100 and also covers some or all of the member 80, thus defining the outer layer of some or all of the battery housing 14. The overmold 90 can be realized using insert molding techniques. An enlarged overmold end 106 represents a portion of the overmold that overlies or abuts the acoustic module, not shown in this figure. Also shown in this figure is an enlarged end 104 of the arm's internal member, which functions to help mechanically couple the arm 100 to the acoustic module and also provides stress relief for the flexible printed circuit 102. The flexible printed circuit 102 passes the entire length of the arm 100, terminates at the battery housing 14, and also terminates at the acoustic module. In some embodiments, as described further below, the flexible printed circuit stress relief member defines an opening through which the flexible printed circuit 102 is threaded. Additionally, in some embodiments, as described further below, the flexible printed circuit defines an open slot along a portion of the length of the flexible printed circuit within the flexible arm to accommodate twisting of the flexible printed circuit about the length of the flexible printed circuit.

[0031] FIG. 4 illustrates an alternative assembly 120 for a flexible arm. In some embodiments, assembly 120 is an alternative to portion 30 illustrated in FIGS. 2A-2C. Assembly 120 includes a flexible printed circuit 124 partially encased in a flexible material 122. This is an alternative to sandwiching the flexible printed circuit between two separate flexible members, as in FIG. 2A. In assembly 120, flexible printed circuit 124 is seated within a serpentine recess 121 pre-formed within a single flexible member 122. This illustrates one non-limiting way to maintain a length of the flexible printed circuit within the flexible arm that is longer than the arm's original rest length. In some embodiments, flexible material 122 is molded from a silicone material or a different elastomer. Material 122 is molded with an internal slot 121 created using a removable insert. Flexible printed circuit 124 is then placed within slot 121 as shown. Thus, material 122 secures flexible printed circuit 124 in the configuration of slot 121. Slot 121 defines one or more curves along its length such that it is longer than the central longitudinal axis of material 122. When assembly 120 is used in a flexible arm, the flexible printed circuit in the arm is longer than the original rest length of the arm.

[0032] FIG. 5A is a schematic diagram of an embodiment 140 of a flexible arm. A flexible printed circuit 142 runs the entire length of the arm. A portion 145 of the flexible printed circuit 142 has several simple open curves that are held in place by a flexible material 144 that encases at least a portion of the flexible printed circuit 142. Members 150 and 160 are positioned at the end of the arm 140 and each act as stress relief for the flexible printed circuit as well as mechanically coupling the arm to the battery housing and acoustic module (neither of which are shown in this figure). In some embodiments, members 150 and 160 are made from an engineered plastic such as nylon or acrylonitrile butadiene styrene (ABS) and act to reinforce the arm and strengthen it at the distal locations of the arm that are coupled to the battery housing and acoustic module.

[0033] Member 150 is also illustrated in FIG. 5B . Member 150 can be made by injection molding, machining, or stamping. In some embodiments, member 150 is a single member. Member 150 includes a body 152 having one or both openings 155 and 156 and an enlarged end 154 configured to be mechanically coupled to one of the battery housing and the acoustic module, such as by an interference fit and / or adhesive. As shown in FIG. 5A , in some embodiments, flexible printed circuit 142 passes through one of openings 155 and 156, which helps provide stress relief. In some embodiments, arm 140 is completed by overmolding with a flexible material that encases all or substantially all of member 140. The overmolding fills, or at least substantially fills, openings 155 and 156, thus anchoring member 150 within the arm. In some embodiments, second member 160 includes one or more openings (not shown) that are also filled with overmolded material. In some embodiments, member 160 acts as a guide for flexible printed circuit 142, which can pass over the back surface of member 160, as shown in Figure 5A. Member 160 also includes an enlarged end 164 that is configured to be mechanically coupled to one of the battery housing and the acoustic module, such as by an interference fit and / or adhesive.

[0034] 6 partially illustrates a flexible printed circuit assembly 180 for a flexible arm. The assembly 180 includes a flexible printed circuit 182. To accommodate twisting of the arm about its longitudinal axis with reduced fracture of the flexible printed circuit 182, the flexible printed circuit 182 has an open slot 184 along a portion of the length of the flexible printed circuit. When the flexible printed circuit 182 twists, stress is at least partially relieved by the open slot 184. This may result in less stress on any metal conductors in the flexible printed circuit 182, which may increase the useful life of the conductors.

[0035] Having described several aspects of at least one embodiment, it will be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure and be 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]

[0036] 10 Open-back headphones 12 Acoustic Module 14 Battery housing 20 Flexible Arm 30 portions 31 Flexible Printed Circuits 33 Arm center longitudinal axis 40 Flexible materials 42 parts 44 parts 52, 54, 56, 58 Simple open curves 70 Flexible arm part 72 Overmolding 80 Housing member 90 Overmolding 100 flexible arm 102 Flexible Printed Circuit 104 Enlarged end 106 Overmolded End 120 Assembly 121 Serpentine recess (internal slot) 122 Flexible member 124 Flexible Printed Circuit 142 Flexible Printed Circuits 144 Flexible materials 145 parts 150 parts 152 Main Unit 154 Enlarged end 155, 156 Openings 160 parts 164 Enlarged end 180 Flexible Printed Circuit Assembly 182 Flexible Printed Circuits 184 Open Slots

Claims

1. a flexible arm positioned between an acoustic module of the open headphones and a battery housing of the open headphones, the flexible arm being 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 flexible material encasing at least a portion of the flexible printed circuit; A flexible arm, wherein the length of the flexible printed circuit within the flexible arm is longer than the original resting 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 resting position of the flexible arm.

2. The flexible arm of claim 1 , wherein the flexible printed circuit defines one or more open curves within the flexible arm along a length of the flexible printed circuit.

3. The flexible arm of claim 2 , wherein the one or more open curves are simple open curves.

4. The flexible arm of claim 1 , wherein the original rest position of the flexible arm is along an axis of bending.

5. The flexible arm of claim 4 , wherein the flexible printed circuit defines at least one simple open curve within the flexible arm along the length of the flexible printed circuit.

6. 6. The flexible arm of claim 5, wherein 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.

7. The flexible arm of claim 6 , wherein each downward simple open curve of the flexible printed circuit is adjacent to one or more of the upward simple open curves.

8. The flexible arm of claim 4 , wherein the bending axis defines a simple open curve.

9. The flexible arm of claim 8 , wherein the curved axis is generally “C” shaped.

10. The flexible arm of claim 4 , wherein the bending axis bisects the flexible arm, and different portions of the first surface of the flexible printed circuit are on different sides of the bending axis.

11. The flexible arm of claim 1 , wherein the flexible material comprises two mating members each defining a series of simple open curves along the original, resting length of the flexible arm.

12. The flexible arm of claim 11 , wherein the simple open curves of the two mating members are complementary.

13. 13. The flexible arm of claim 12, wherein the two mating members each define a corrugated mating surface, a convex portion of one member being aligned with and mating with a concave portion of the other member, and the flexible printed circuit being positioned between the mating surfaces of the two mating members.

14. The flexible arm of claim 1 further comprising an overmold surrounding the flexible material along at least a majority of the original resting length of the flexible arm.

15. The flexible arm of claim 14 , wherein the overmold further covers at least a portion of the battery housing.

16. The flexible arm of claim 1 further comprising a flexible printed circuit stress relief member adjacent to the flexible material, the flexible printed circuit stress relief member defining an opening through which the flexible printed circuit is threaded.

17. 2. The flexible arm of claim 1, wherein the flexible printed circuit defines an open slot along a portion of the length of the flexible printed circuit within the flexible arm to accommodate twisting of the flexible printed circuit about its length.

18. A flexible arm positioned between an acoustic module of an open headphone and a battery housing of the open headphone, the flexible arm being 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, the original rest position of the flexible arm being generally along a "C"-shaped curved axis, the flexible arm comprising: 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 flexible material encasing at least a portion of the flexible printed circuit; A flexible arm, wherein the flexible printed circuit defines at least one simple open curve along the length of the flexible printed circuit within the flexible arm, such that the length of the flexible printed circuit within the flexible arm is longer than the original resting 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 resting position of the flexible arm.

19. 20. The flexible arm of claim 18, wherein 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, each downward simple open curve of the flexible printed circuit adjacent to an upward simple open curve.

20. 20. The flexible arm of claim 19, further comprising a flexible printed circuit stress relief member adjacent to the flexible material, the flexible printed circuit stress relief member defining an opening through which the flexible printed circuit is threaded.

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