HK1245549B - Earpiece for providing passive noise attenuation - Google Patents

Description

Headphones that provide passive noise attenuation

This application is a divisional application of an international application filed on July 24, 2012, with international application number PCT/US2012/047975, national application number 201280037522.8, and entitled “PASSIVE NOISE ATTENUATION FOR HEADPHONES”, which has entered the Chinese national phase.

Background Art

This specification describes a structure for providing passive noise attenuation via an in-ear earphone and for positioning and retaining the earphone in the ear.

Summary of the Invention

In one aspect, an in-ear earphone includes: an acoustic driver; an acoustic channel that conducts sound waves emitted by the acoustic driver to a user's ear canal; a positioning and retaining structure that engages lateral features of the user's ear to position the earphone and hold it in place without any structure external to the earphone; and a generally conical structure configured such that the smaller end of the conical structure is smaller than the entrance to the user's ear canal and the larger end is larger than the entrance to the user's ear canal, and formed from a material that conforms to the ear canal entrance to seal the ear canal. The material may have a hardness of 30 Shore A or less. The material may have a modulus of 2 gf/mm or less. The material may be silicone rubber. The material may be a thermoplastic elastomer. The material may be thermoplastic polyurethane. The positioning and retaining structure may include a first leg and a second leg that are attached to each other at an attachment end to form a plug and attached to the earphone body at the other end. The positioning and retaining structure may provide at least three modes to prevent the earphone from rotating clockwise beyond a rotational position. The modes may include the tip of the plug contacting the bottom of the helix; the tip of the plug wedging beneath the antihelix in the cymba concha area; and the inner leg contacting the bottom of the helix. The positioning and retaining structure may include an inner leg and an outer leg. The inner leg and the outer leg may be attached to the body at an attachment end and to each other at a joint end. When the earphone is in its intended position, the outer leg may be positioned against the anti-helix at the back of the concha, the body engaging the ear canal, and at least one plug may be positioned below the anti-helix; or a portion of at least one of the body and the outer leg may be positioned below the anti-tragus. The positioning and retaining structure may include an inner leg and an outer leg attached to each other at an attachment end and to the earphone body at a second end. The inner leg and the outer leg may be arranged to provide at least three modes for preventing the earphone from rotating clockwise. These modes may include the plug contacting the bottom of the helix; the plug wedging under the anti-helix; and the inner leg contacting the bottom of the helix. The inner leg and the outer leg may further be arranged such that when the earphone is in its intended position, the outer leg is positioned against the anti-helix at the back of the concha, the body engaging the ear canal, and at least one plug may be positioned below the anti-helix; or a portion of at least one of the body and the outer leg may be positioned below the anti-tragus. The generally conical structure may include an opening therethrough to conduct sound waves from the acoustic driver to the ear canal. The opening may have a generally elliptical cross-section. The generally conical structure may taper substantially linearly from the larger end to the smaller end. The generally conical structure may have a substantially uniform thickness. The material of the user's positioning and retaining structure may have a different hardness than that of the generally conical structure. The material of the structure that conducts sound waves emitted by the acoustic driver to the user's ear canal may have a different hardness than that of the material of the user's positioning and retaining structure and the material of the generally conical structure.

In another aspect, an earplug for an in-ear earphone includes a positioning and retaining structure that engages features on the side of the ear to position the earphone and hold it in place without any structure external to the earphone, and also includes a generally conical structure configured such that the smaller end of the conical structure is smaller than the entrance to the user's ear canal and the larger end of the conical structure is larger than the entrance to the user's ear canal, and is formed of a material that conforms to the entrance to the ear canal to seal the ear canal. The positioning and retaining structure and the generally conical structure may comprise the same material. The positioning and retaining structure and the generally conical structure may be integral structures.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features, objects and advantages will become apparent from the following detailed description when read in conjunction with the accompanying drawings, in which:

FIG1A is a side view of a human ear;

1B and 1C are exemplary cross-sections of a human ear;

FIG2 is a perspective view of the earphone;

FIG3 is a side view of an earphone and a human ear;

FIG4 shows cross-sections of two exemplary human ears;

5A-5D are views of an earphone;

FIG6 shows cross-sections of two exemplary human ears;

7A-7C are views of a portion of the earphone of FIGS. 2 and 5A-5D ;

8A and 8B are cross-sections of the earphone portion of Figs. 7A-7C; and

9A-9C are views of an alternative embodiment of an earphone.

DETAILED DESCRIPTION

This specification describes an in-ear headphone designed to fit in the right ear. The headphone designed to fit in the left ear is a mirror image of the headphone described below, operates according to the same principles, and is therefore not described here.

FIG1A shows the side of a person's right ear, with some features identified. There are many different ear sizes and geometries. Some ears have additional features not shown in FIG1A. Some ears lack some of the features shown in FIG1A. Some features may be more or less prominent than those shown in FIG1A. FIG1B and FIG1C show two exemplary cross-sections of a person's ear, with some features identified. The ear canal is an irregularly shaped tube with a variable cross-sectional area and a non-straight centerline. Some of the features identified are the entrance to the ear canal and the main part of the ear canal. In this specification, the entrance to the ear canal refers to the part of the ear canal near the concha, where the wall of the ear canal is substantially non-parallel to the centerline of the ear canal. The exact structure of the human ear varies widely from individual to individual. For example, in the cross-section of FIG1B , there is a relatively sharp transition from an ear canal wall that is non-parallel to the centerline of the ear canal 30-1B to a wall that is substantially parallel to the centerline of the ear canal, so that the entrance to the ear canal 32-1B is relatively short. In the cross section of FIG. 1C , there is a more gradual transition from walls that are non-parallel to the centerline of the ear canal to walls that are substantially parallel to the centerline 30 - 1C of the ear canal, so that the entrance 32 - 1C of the ear canal is relatively long.

FIG2 shows an earphone 10. The earphone 10 may include a shank 52 for locating a cable, etc., an acoustic driver module 14, and a plug 60 (more clearly identified in FIG5A-5D). Some earphones may lack the shank 52 but may include an electronics module (not shown) for wireless communication with an external device. Other earphones may lack the shank and acoustic driver module and may function as passive earplugs. The plug 60 includes a positioning and retaining structure 20, which in this example includes an outer leg 22 and an inner leg 24. The plug also includes a sealing structure 48.

In operation, the earphone 10 can be placed in the ear and oriented and held in place by the positioning and retaining structure 20 and the rest of the earphone. The plug 60 includes a passageway that conducts sound waves emitted by the acoustic driver in the acoustic driver module 14 to the ear canal. The positioning and retaining structure 20 that holds the earphone in place extends from the plug 60, without a significant contribution from the portion of the earplug that engages the ear canal, and without any structure on the outside of the earplug. The positioning and retaining structure 20 includes at least an outer leg 22 and an inner leg 24 that are connected at one end to the rest of the earplug and to each other at the other end. The outer legs are curved so as to generally follow the curve of the antihelix and/or cymba concha at the back of the concha. Generally, the flexibility/stiffness of the entire positioning and retaining structure is more important than the flexibility/stiffness of the material from which the positioning and retaining structure is made or the flexibility/stiffness of any one component of the positioning and retaining structure. The outer leg 22 and the inner leg 24 can lie in a plane.

3 , the earphone plug is placed in the ear and gently pushed inward, preferably in a counterclockwise direction as indicated by arrow 43. Pushing the body into the ear causes the outer legs 22 to seat beneath the antihelix and causes the outlet section of the plug 48 (not shown in this view for convenience) to enter the ear canal a very small amount depending on the size and geometry of the ear canal entrance.

The body is then rotated clockwise, as indicated by arrow 41, until a condition occurs where the body cannot be rotated further. This condition may include: the tip 35 of the plug contacting the bottom of the helix; the inner leg 24 contacting the bottom of the helix; or the tip 35 becoming wedged behind the anti-helix in the cymba concha area. While the positioning and retention structure provides all three conditions (hereinafter referred to as "modes"), not all users will experience all three conditions; for most users, at least one mode will occur. Which conditions occur will depend on the size and geometry of the user's ear.

Rotating the earphone clockwise also causes the tip and outer leg to engage the cymba concha area and seat under the anti-helix. When the body and positioning and retaining structure 20 are in place, the positioning and retaining structure and/or body contact the ear in at least two ways for most people, and for many people in more than one way: the length 40 of the outer leg 22 contacts the anti-helix at the back of the concha; the tip 35 of the positioning and retaining structure 20 is under the anti-helix; the outer leg 22 or a portion of the plug 60 (of the previous figure), or both, are under the anti-tragus; and the plug 60 contacts the ear canal entrance under the tragus. These two or more points of contact hold the earphone in place, providing greater stability. The distribution of force and the flexibility of multiple portions of the body and outer leg contacting the ear reduce pressure on the ear, providing a more comfortable fit.

It is desirable to properly orient the earphone when placed in the ear so that it is stable (i.e., stays in the ear), comfortable, and for some applications provides significant passive attenuation of ambient noise. One approach to providing stability and proper orientation is described above and more fully in U.S. patent application Ser. No. 12/860,531, which is incorporated herein by reference in its entirety.

One device for providing significant passive attenuation is a structure (e.g., a "Christmas tree" structure as described in U.S. Patent Application 2004/0163653, or a "mushroom" structure as described in U.S. Patent 5,957,136, or a disc-shaped flange or similar structure as described in U.S. Patent 6,129,175) that fits into the main portion of the ear canal and itself seals to the ear canal by applying radial pressure on the walls of the main portion of the ear canal, as indicated by arrows 70, 72, and 74 in FIG. 4 . The radial pressure can originate from or be supplemented by inward clamping pressure. Such a device can have some undesirable side effects, such as a poor seal, discomfort, or even pain, because the geometry and size of the ear canal vary widely among individuals and because such a device intrudes further into the ear canal than desired in some individuals. The main portion of the ear canal, particularly the main portion near the middle ear, is very sensitive, so the further a structure extends into the ear, the more uncomfortable it becomes. Another device for providing significant passive attenuation is a structure (in addition to the earpiece itself) that provides inward clamping pressure to push the appropriate structure against the side of the head or ear. Examples include the headband of a conventional headset or the yoke of a stethoscope, such as described in U.S. Patent 4055233. However, for in-ear headphones, light weight and small size are desirable features, and headbands and yokes add weight and structure.

The earphone of Figure 2 includes a plug that provides orientation, stability and a good seal to the entrance of the ear canal and the ear structures outside the ear canal, without excessive radial pressure and without inward clamping pressure provided by sources not included in the earphone.

Figures 5A-5D show several views of the plug 60. Not all elements of the plug 60 are identified in all views. The plug 60 includes a positioning and retaining structure 20, a body 23, a passage 21 and a sealing structure 48. The body includes a mating surface 25 for connecting to the driver module 14. The passage 21 conducts sound from the driver module through the body and the sealing structure and into the ear canal. The sealing structure 48 includes a frustoconical structure. The frustoconical structure can have an elliptical or oval cross-section (as seen in Figure 7A below), with walls that taper substantially linearly (as seen in Figures 7B, 8A and 8B below). In one embodiment, the structure of the sealing structure and the material from which it is made result in a modulus measured in the direction of arrow 34 in Figure 5B in the range of 0.2 to 2 gf/mm. Examples of suitable materials include silicone, TPU (thermoplastic polyurethane) and TPE (thermoplastic elastomer).

The size of the smaller end 62 of the plug is such that it fits a small amount inside the ear canal of most users so that the sealing structure 48 contacts the entrance to the ear canal but does not contact the inside of the ear canal. The size of the larger end 64 of the plug is such that it is larger than the entrance to the ear canal of most users.

The positioning and retaining structure 20 and the sealing structure 48 can be a single piece, made of the same material, for example, a very soft silicone rubber having a durometer of 30 Shore A or less. The wall of the sealing structure 48 can have a uniform thickness; it can be very thin, for example, with the thickest portion of the wall being less than 1 mm and tapering to the bottom of a frusto-conical structure, so that the wall deflects easily, thereby easily conforming to the contours of the ear and providing a good seal and good passive attenuation without exerting significant radial pressure on the ear canal. Because different parts of the earphone perform different functions, it is desirable that the different parts of the earphone be made of different materials, or of materials having different durometers or moduli. For example, the durometer hardness of the retaining structure 20 can be selected for comfort (e.g., 12 Shore A), the durometer of the plug 48 can be slightly higher (e.g., 20 Shore A) for better fit and seal, the durometer of the earplug portion that mechanically couples the earplug to the acoustic module 14 can be higher (e.g., 70 Shore A) for better hold and seal to the earplug portion that mechanically couples the earplug to the acoustic module 14, and in some cases, to provide a more consistent shape and size for the passageway through which sound waves propagate.

The earplug according to Figures 5A-5D seals to the entrance of the ear canal to provide passive attenuation and applies little radial pressure to the main portion of the ear canal, or does not contact the main portion of the ear canal at all, as shown in Figure 6.

Figures 7A-7C show external views of plug 60, and Figures 8A and 8B show cross-sectional views of plug 60, wherein the plug has the dimensions of a typical embodiment. In the embodiment of Figures 7A-7C and 8A and 8B, the sealing structure 48 is oval, with the major axis at the smaller end being 7.69 mm and the minor axis being 5.83 mm, while the major axis at the larger end is 16.1 mm and the minor axis is 14.2 mm. A sealing structure with these dimensions fits the ear canal of many users, such that the smaller end extends only a small amount into the ear canal and does not contact the walls of the ear canal, the larger end does not fit in the ear canal, and the sealing structure 48 engages the ear canal entrance. Smaller or larger versions can be used for users with below-average or above-average ears, including children. Versions with similar overall dimensions but different aspect ratios between the major and minor axes can accommodate users whose ear canal entrances are more or less round than average.

In some examples, the sealing structure 48 and the body 23 together are sufficient to position and retain the earphone in the user's ear, and the retaining structure 20 does not need to be included. This design 60' is shown in Figures 9A to 9C. Friction and interference between the body 23 and the concha retain the earphone. Positioning is aided by the geometric relationship between the body 23 and the sealing structure 48 so that the body fits into the concha when the sealing structure is properly positioned at the entrance to the ear canal and seals to the entrance to the ear canal. Adding at least one of the body 23 or the retaining structure 20 (e.g., from Figure 2) to the sealing structure 48 eliminates the need for the sealing structure to retain the earphone itself, which allows the sealing structure to be more compliant and deformable as might be desired if it were also responsible for retaining the earphone.

The overall frustoconical shape of the sealing structure, i.e., its substantially linear sides combined with its thin walls and elliptical cross-section allows the sealing structure to be more deformable than prior art sealing structures which tend to have rounded walls (i.e., mushroom-shaped rather than cone-shaped). The rounded wall has greater containment strength such that if it is compressed along one transverse axis (i.e., an axis perpendicular to the axis running the length of the structure), the structure bulges outward along the perpendicular transverse axis. As a result of the wall becoming less compliant along the other transverse axes in response to deformation in the first transverse axis, compression from multiple radial directions can cause buckling along the curve of the wall, resulting in gaps in the seal between the sealing structure and the ear, or pressure points where the sidewall cannot be compressed in all directions. In contrast, the thin conical walls of the sealing structure 60 can be compressed in multiple directions simultaneously without buckling or increasing pressure elsewhere.

Various uses of the specific devices and techniques disclosed herein and devices and techniques different therefrom can be made without departing from the inventive concept. Therefore, the present invention should be construed as including each and every novel feature and novel feature combination disclosed herein, and limited only by the spirit and scope of the claims.

Claims (20)

1. An earplug for an in-ear headphone, comprising the following integrally formed components: The main body, which can rest in the ear canal of the user's ear to support the acoustic driver of the headphones when the headphones are positioned in the user's ear; An acoustic channel that passes through the body to conduct sound waves emitted by the acoustic driver to the user's ear canal; Positioning and holding structure, which engages with the features on the side of the user's ear to position the earphone and hold it in place without any structure outside the earphone; The structure is roughly conical, such that the smaller end of the conical structure is smaller than the entrance to the user's ear canal, and the larger end of the conical structure is larger than the entrance to the user's ear canal, wherein the main body is connected to the conical structure through the acoustic channel, the acoustic channel extending through the interior of the conical structure and terminating at the smaller end of the conical structure. The conical structure includes a thin wall extending from a smaller end located at the end of the acoustic channel to a larger end and is internally open and separate from the acoustic channel, and the conical structure is formed of a material conforming to the entrance of the ear canal to seal the ear canal; The acoustic channel includes a straight channel that extends from the acoustic driver through the body and is aligned with the entrance of the ear canal. 2. The earplug of claim 1, wherein the body includes an earphone mating surface for coupling to an acoustic driver of an earphone, such that when the earplug is inserted into the user's ear, the conical structure and the body are positioned between the user's ear and the housing. 3. The earplug of claim 1, wherein the positioning and holding structure includes the body. 4. The earplug of claim 1, wherein the positioning and holding structure and the generally conical structure comprise the same material. 5. The earplug of claim 1, wherein the positioning and holding structure comprises: The two ends are attached to each other to form a plug, and the other end is attached to the outer and inner legs of the body. 6. The earplug of claim 1, wherein the generally tapered structure tapers substantially linearly from the large end to the small end. 7. The earplug of claim 1, wherein the generally conical structure has a substantially uniform thickness. 8. The earplug of claim 1, wherein the cross-section of the generally conical structure is substantially elliptical. 9. The earplug of claim 1, wherein the material of the positioning and retaining structure has a different hardness than the material of the generally conical structure. 10. The earplug of claim 1, wherein the generally conical structure has flexibility and deformability, thereby allowing the wall to be compressed along two different lateral axes without buckling. 11. The earplug of claim 1, wherein the material has a hardness of 30 Shore A or less. 12. The earplug of claim 1, wherein the material has a stiffness of 2 gf/mm or less. 13. The earplug of claim 1, wherein the material is silicone rubber. 14. The earplug of claim 1, wherein the material is a thermoplastic elastomer. 15. The earplug of claim 1, wherein the material is thermoplastic polyurethane. 16. The earplug of claim 1, wherein the generally conical structure includes an opening therethrough to conduct sound waves from the acoustic driver to the user's ear canal. 17. The earplug of claim 16, wherein the hardness of the material of the structure surrounding the opening to conduct sound waves from the acoustic driver to the user's ear canal is different from the hardness of the material of the positioning and holding structure and the material of the generally conical structure. 18. The earplug of claim 1, wherein the cross-section of the opening of the acoustic channel is substantially elliptical. 19. The earplug of claim 18, wherein at least two of the earplugs in a set of earplugs have openings with different elliptic eccentricities. 20. The earplug of claim 19, wherein the positioning and holding structures of at least two earplugs having openings with different eccentricities have the same dimensions.