BACKGROUND

[1] This disclosure relates to wax guards for earphones, and in particular, integrating wax guards into ear tips. [2] Figure 1 shows an earphone 100 having an earphone body 112 and an ear tip 102, as described in U.S. Patent application 15/597,567, filed on May 17, 2017, titled Headphones with External Pressure Equalization Path, and incorporated here by reference. The ear tip incorporates a retaining feature from U.S. Patent 8,989,426, titled Earpiece Positioning and Retaining, and an ear canal sealing feature from U.S. Patent 8,737,669, titled Earpiece Passive Noise Attenuating, both also incorporated here by reference. U.S. Patent 8,355,522, titled

Earphone Cushions and also incorporated here by reference, describes a construction technique for such ear tips, shown in figures 10A-10D, in which an inner core 502 of the ear tip 500 is formed of a harder material than the outer structures 504. The harder material provides structure and secure connection to the earphone body, while the softer material provides a compliant and comfortable surface for interfacing with the human body.

SUMMARY

[3] In general, in one aspect, an ear tip for an earphone includes an interior mating surface for attaching the ear tip to the earphone, the interior mating surface at least partially surrounding a cavity where the earphone will be located when the ear tip may be so attached, an outer surface including features corresponding to human ear anatomy, a nozzle extension providing a passageway from the interior cavity to space outside the ear tip, a wax guard in the nozzle extension, the wax guard blocking the passageway, and a plurality of holes through the wax guard, the holes sized and arranged to allow sound to pass along the passageway, while inhibiting ear wax from passing along the passageway. [4] Implementations may include one or more of the following, in any combination. The wax guard may be generally elliptical in shape, with the plurality of holes arranged in a pattern uniformly spread around the wax guard. The wax guard may be generally elliptical in shape, with the plurality of holes arranged in a pattern confined to a circular shape having a diameter less than the shorter axis of the elliptical shape of the wax guard. The holes may be uniform in diameter along their extent through the wax guard. The plurality of holes may include seven holes having a diameter of around 0.031 mm. The holes may be tapered in diameter along their extent through the wax guard, having narrower ends on a surface of the wax guard facing out of the passageway and wider ends on a surface of the wax guard facing towards the cavity. The holes may have a dimeter of around 0.031 mm at their narrow ends. The ear tip may be composed of two different materials having different hardness, a first, harder material providing the interior mating surface, and a second, softer material providing the outer surface; the wax guard may include the first material in a unitary structure with the material providing the interior mating surface. The first material may have a hardness between 70 and 85 Shore A. The second material may have a hardness of 20 ± 4 Shore A. The mating surface and the wax guard may be positioned, relative to each other, such that when the earphone is attached to the ear tip, a gap will be present between an end of a nozzle of the earphone and the wax guard. [5] In general, in one aspect, an earphone includes an earphone body, including an aperture through which sound exits, and an exterior surface. An ear tip for attachment to the earphone includes an interior mating surface corresponding to at least a portion of the exterior surface of the earphone body, an outer surface including features corresponding to human ear anatomy, a nozzle extension providing a passageway from the aperture of the earphone body to space outside the earphone, a wax guard in the nozzle extension, the wax guard blocking the passageway, and a plurality of holes through the wax guard, the holes sized and arranged to allow sound to pass along the passageway, while inhibiting ear wax from passing along the passageway.

[6] Implementations may include one or more of the following, in any combination. The earphone body may include a nozzle extending from the earphone body, the aperture located at an end of the nozzle and covered by a screen, with a gap remaining between the screen and the wax guard when the ear tip is attached to the earphone.

[7] In general, in one aspect, an ear tip for an earphone includes a first material, having a first hardness, providing an interior mating surface for attaching the ear tip to the earphone, the interior mating surface at least partially surrounding a cavity where the earphone will be located when the ear tip may be so attached, and a second material, having a second hardness, providing an outer surface including features corresponding to human ear anatomy, a nozzle extension formed of at least the second material, providing a passageway from the interior cavity to space outside the ear tip. A wax guard is formed of the first material and located within the nozzle extension, the wax guard blocking the passageway. A plurality of holes through the wax guard are sized and arranged to allow sound to pass along the passageway, while inhibiting ear wax from passing along the passageway.

[8] Advantages include preventing wax from entering the earphones, while allowing sound to pass unimpeded, without the use of additional parts. This allows extended wear of the earphones, such as overnight or all day.

[9] All examples and features mentioned above can be combined in any technically possible way. Other features and advantages will be apparent from the description and the claims.

BRIEF DESCRIPTION OF TH E DRAWINGS

[10] Figure 1 shows a perspective view of an earphone.

[11] Figure 2 shows a cross-sectional view of an improved version of the earphone of figure 1.

[12] Figure 3 shows a side view of the earphone of figure 2. [13] Figures 4, 6, and 8 show a front view of a headphone ear tip, looking into the outlet.

[14] Figures 5, 7, and 9 show the reverse view of the ear tips of figures 4, 6, and 8, looking through the ear tip in the direction of the outlet.

[15] Figures 10A, 10B, IOC, and 10D show a back, top, side, and perspective view of an ear tip for an earphone. DESCRIPTION

[16] A problem facing in-ear earphones that are intended to be worn for extended periods of time is the build-up of ear wax in the ear, and its migration into the earphone. In particular, the earphone shown in figure 1 is intended to be worn overnight, potentially for eight to even twelve hours at a time. Similarly, hearing aids are intended to be worn all day. If the ear wax migrates into the earphone, aside from impeding performance by physically blocking sound, it may interfere with earphone electronics.

[17] Figures 2 through 8 show modified ear tips that integrate a protective guard to prevent ear wax that enters through the outlet of the ear tip from reaching the earphone body and the electronics within it. In figure 2, the ear tip 102 includes a retaining member 104, an ear canal sealing structure 106 extending from a nozzle extension 108, and an inner core 110. The inner core provides a mating surface that corresponds to the outer shape of the earphone body 112, and includes a guard 120 that extends over the outlet 114 at the end of nozzle 116 of the earphone body 112. A hole 122 through the guard 120 allows sound to exit, while preventing ear wax from entering. More than one hole is likely provided, as discussed below; the sectional view used for figure 2 happens to show only one. Advantageously, a gap 121 between the guard 120 and a screen in the outlet 114 at the end of the nozzle 116 prevents wax from contacting the screen, which would be particularly difficult to clean. The ear tip can be removed from the earphone, and any wax caught by the guard can be removed, such as by washing the tip.

Alternatively, the tip may be replaceable at significantly lower cost than the earphone body.

[18] Figures 4 and 5, 6 and 7, and 8 and 9 show three alternative arrangements of holes in the guard. Figures 4, 6, and 8 show the view of the guard looking into the nozzle extension, and figures 5, 7, and 9 show the view looking into the back of the ear tip 102, with the earphone body 112 removed. In the example of figures 4 and 5, the holes 122 have uniform cross-section, which is also shown in figure 2. Seven holes are arranged in a figure-eight pattern, generally covering the elliptical opening of the nozzle, while staying far enough from the edge to allow the holes to be laser-drilled, as discussed below, without interference from the nozzle extension.

The size and number of the holes is selected to balance the tradeoff between sound

transmission and wax blocking. We have found that the total cross sectional area of all the holes dominates the acoustic performance, while the size and location of individual holes controls the amount of wax ingress. In the examples shown, seven holes having a diameter of 0.31 mm are used, based on the acoustic needs of the earphone used.

[19] In the examples of figures 6 through 9, the holes 222, 322 are tapered, being larger at the inner surface of the guard and smaller at the outer surface. In some examples, the holes had a diameter of 0.31 mm at the narrow end and a 16 degree taper. The holes are arranged in hexagonal pattern around a circle (plus one in the center) in the center of the elliptical nozzle opening. The hexagonal shape is rotated 30 ^° between the example of figures 6 and 7 and that of figures 8 and 9, such that in the example of figures 6 and 7, the long axis of the hexagonal shape is aligned with the long axis of the elliptical shape of the nozzle opening. Conversely, in the examples of figures 8 and 9, the long axis of the hexagonal shape is aligned with the short axis of the elliptical shape of the nozzle opening.

[20] As mentioned earlier, the inner and outer layers of the ear tips are formed of materials having different hardness. The wax guard is formed as part of the inner, harder material in order to better maintain the shape of the holes, and the positioning of the guard relative to the earbud body and the nozzle extension of the ear tip. In particular, the harder material will resist any deformation of the nozzle extension caused by insertion into a particular user's ear canal. In some examples, the outer layer is formed of material having a hardness of 20 ± 4 Shore A, while the inner layer has a hardness in the range of 70 to 85 Shore A. The two layers can be formed using any appropriate manufacturing technique. In one example, they are both formed through injection molding, with the inner core of the harder material being molded first, and then inserted into the mold for the softer outer layer. In other examples, the harder material is molded using compression molding and then placed in the injection mold for the softer outer layer. For the example of figures 2, 4, and 5, with straight-sided holes, the holes may be laser-drilled after the wax guard is molded with an intact plate. For the examples of figures 6 through 9, with tapered holes, the holes may be formed during molding through the use of pins or other appropriate features in the mold.

[21] A number of implementations have been described. Nevertheless, it will be understood that additional modifications may be made without departing from the scope of the inventive concepts described herein, and, accordingly, other embodiments are within the scope of the following claims.