Patent Description:
The present disclosure relates generally to apparatuses, systems, and methods for hearing protection devices, and more particularly, to apparatuses, systems, and methods for improving and/or manipulating noise attenuation of hearing protection devices.

A hearing protection device (also known as HPD) refers to a protection device that, for example, may be worn in or over the ears to reduce the level of noise entering the ear. HPDs are used in many situations. For example, when a user is exposed to hazardous noise, he may prefer to wear a HPD to prevent noise-induced hearing loss. HPDs may include, for example, earmuffs, earplugs, and other devices that may block or reduce the passage of environmental sound to a user's ear canal.

Existing devices are plagued by many limitations and restrictions. For example, they do not provide sufficient noise attenuation. In addition, they are not tuned to any particular frequency of environmental noise.

Specific embodiments are defined in the dependent claims. Various embodiments described herein relate to methods, apparatuses, and systems for improving the performance of hearing protection devices. In particular, various embodiments increase noise attenuation by disposing a plurality of fractal elements on an inner surface of a protection cup for a hearing protection device.

In accordance with various embodiments, a protection cup for a hearing protection device is provided. The protection cup comprises an outer surface, an inner surface on an opposite side from the outer surface, and a plurality of fractal elements disposed on the inner surface. The plurality of fractal elements comprise a plurality of first fractal elements protruding from the inner surface of the protection cup, and a plurality of second fractal elements protruding from the inner surface of the protection cup. The plurality of first fractal elements and the plurality of second fractal elements form a plurality of regions on the inner surface.

In some embodiments, the plurality of first fractal elements are longitudinal fractal elements, and the plurality of second fractal elements are transverse fractal elements. The transverse fractal elements are positioned perpendicular to the longitudinal fractal elements.

The plurality of fractal elements further comprise a plurality of additional fractal elements, and the plurality of additional fractal elements are disposed within at least one of the plurality of regions on the inner surface.

In some embodiments, each of the plurality of additional fractal elements comprises a longitudinal segment and at least one transverse segment.

In some embodiments, two or more of the plurality of additional fractal elements are connected through longitudinal segments of the two or more of the plurality of additional fractal elements.

In some embodiments, each of the plurality of additional fractal elements further comprises a plurality of leg segments, wherein the plurality of leg segments are disposed at end points of the at least one transverse segment.

In some embodiments, the plurality of fractal elements are molded on the inner surface of the protection cup.

In some embodiments, the plurality of additional fractal elements are of the same size.

In some embodiments, the inner surface of the protection cup comprises a protruding portion.

In some embodiments, the plurality of fractal elements further comprise a plurality of diagonal fractal elements.

In accordance with various embodiments, a method for manufacturing a protection cup for a hearing protection device is provided. The method comprises molding an outer surface, molding an inner surface on an opposite side from the outer surface, and molding a plurality of fractal elements on the inner surface. Molding a plurality of fractal elements on the inner surface further comprises molding a plurality of first fractal elements protruding from the inner surface of the protection cup, molding a plurality of second fractal elements protruding from the inner surface of the protection cup. The plurality of first fractal elements and the plurality of second fractal elements form a plurality of regions on the inner surface. In some embodiments molding the plurality of fractal elements on the inner surface further comprises adjusting the plurality of fractal elements based on attenuation ratings.

The phrases "in one embodiment," "according to one embodiment," and the like generally mean that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure, and may be included in more than one embodiment of the present disclosure (importantly, such phrases do not necessarily refer to the same embodiment).

If the specification states a component or feature "may," "can," "could," "should," "would," "preferably," "possibly," "typically," "optionally," "for example," "often," or "might" (or other such language) be included or have a characteristic, that a specific component or feature is not required to be included or to have the characteristic.

Referring now to <FIG>, various views of an example protection cup <NUM> for a hearing protection device in accordance with various embodiments of the present disclosure are illustrated herein. In some examples, protection cup <NUM> refers to the shell of a hearing protection device (such as earmuffs). For example, the protection cup <NUM>, in an example hearing protection device, may receive and house noise-absorbing materials, such as a cotton or a foam cushion. In some examples, a sealing section (for example, foam cushion) may seal and enclose the protection cup so that it is insulated. An exterior surface of the sealing section may contact the user's ear when the user is wearing the example hearing protection device.

In some examples, protection cup <NUM> may be in the shape of an oval cup having its shortest diameter in the transverse direction and the longest diameter in the longitudinal direction. In some examples, a protection cup may be made of rigid plastic material, including, for example, acrylonitrile butadiene styrene (ABS). Additionally or alternatively, other materials may be used for the protection cup <NUM>.

Protection cup <NUM>, in accordance with various embodiments of the present disclosure, may be implemented in different kinds of hearing protection devices, including passive hearing protection devices, electronic hearing protection devices, active hearing protection devices, consumer electronic headphones, and/or the like.

Specifically, and with reference to example passive hearing protection devices, the material and structure of the protection cup <NUM> may be used to attenuate noise. In contrast and in example active hearing protection devices, electronic noise cancellation techniques (such as casting an audio signal to cancel out the environmental noise) may be implemented to further increase noise attenuation. For example, noise cancelling circuitry may be included in an example active hearing protection device. By way of further example, a speaker array may be disposed within the protection cup so that a user wearing an example consumer electronic headphone can still hear some external noise, such as important announcement, from the speaker array.

<FIG> illustrates the protection cup <NUM> that includes an outer surface <NUM>. In some examples, the outer surface <NUM> may comprise an outer center portion <NUM> that is sunken from the surrounding area of the outer surface <NUM>, which effectively creates a protruding portion <NUM> on the inner surface <NUM>, as illustrated in <FIG> and described hereinafter.

The outer surface <NUM>, as shown in <FIG>, comprises a pair of knobs 129A and 129B. In some examples, a headband may be used to connect a pair of protection cups (for example, via the knobs 129A and 129B). The headband may be made of elastic material, such that the headband can be securely positioned on a user's head and the protection cups be securely positioned on the user's ears. Additionally or alternatively, the pair of protection cups may be connected using a neckband so that a user can wear the protection cups and a safety hat at the same time.

<FIG> illustrates protection cup <NUM> that defines an inner surface <NUM> opposite to outer surface <NUM>. In various embodiments of the present disclosure, one or more fractal elements (such as the plurality of longitudinal fractal elements <NUM>, the plurality of transverse fractal elements <NUM>, and the plurality of additional fractal elements <NUM> as shown in <FIG>) may be disposed on and protrude or otherwise extend from the inner surface <NUM> of the protection cup <NUM>. As used herein, "fractal elements" refers to a structure that is disposed on and protrudes from a surface (such as, for example, a stiffener). In some examples, a fractal element may be made of rigid plastic material, including, for example, acrylonitrile butadiene styrene (ABS). In some examples, other materials may be used to form a fractal element.

As described herein, one or more fractal elements may intersect, be joined, or otherwise be linked to form a pattern of fractal elements that, in some examples, may provide one or more benefits to noise attenuation. In various embodiments of the present disclosure, the plurality of fractal elements may form one or more patterns on the inner surface of the protection cup. Various example patterns are illustrated in <FIG> and <FIG>.

Referring now to <FIG>, an example measurement diagram of a fractal element is illustrated. The example measurement diagram illustrates example relationships between the thickness of the protection cup T, the width of the fractal element W, and the corner radius of the fractal element R. For example and as is shown in <FIG>, the corner radius R of the fractal element may be more than <NUM> times the thickness of the protection cup T. Further, the width of the fractal element W can be calculated based on the following equation: <MAT> where T is the thickness of the protection cup, and k is the ratio between the width of the fractal element and the thickness of the protection cup. In some embodiments, the ratio k may be in the range of <NUM> to <NUM> (inclusive). In some embodiments, other ratios may be used. By adjusting the values of T and W, various embodiments of the present disclosure can, for example, adjust and/or otherwise influence noise attenuation levels of example hearing protection devices, and meet requirements for different noise attenuation ratings.

In some examples, fractal elements may be molded from the inner surface <NUM> of the protection cup <NUM>. As described in detail further hereinafter, the protection cup <NUM> may be made of, for example but not limited to, rigid plastic or resin material. A liquid form of the material may be shaped using a rigid frame ("a mold") with hollowed-out blocks. These hollowed-out blocks resemble the shapes of the fractal elements. Example details of an example molding process are described further in connection with <FIG>.

Alternatively or additionally, the fractal elements may be affixed or otherwise attached to the inner surface, example details of which are described further in connection with <FIG>. Alternatively or additionally, the fractal elements may be etched from the inner surface <NUM>.

Referring back to <FIG>, the plurality of fractal elements disposed on the inner surface of the protection cup <NUM> may include, for example, a plurality of first fractal elements, a plurality of second fractal elements, and/or a plurality of additional fractal elements. The plurality of first fractal elements, the plurality of second fractal elements, and/or the plurality of additional fractal elements may protrude from the inner surface of the protection cup. The plurality of first fractal elements, the plurality of second fractal elements, and/or the plurality of additional fractal elements may form a plurality of regions on the inner surface, as described in detail hereinafter.

Specifically, and with reference to the example shown in <FIG>, the plurality of first fractal elements are the plurality of longitudinal fractal elements <NUM>, and the plurality of second fractal elements are transverse fractal elements <NUM>. Further, <FIG> illustrates example additional fractal elements as the plurality of additional fractal elements <NUM>.

Each of the plurality of longitudinal fractal elements <NUM> is aligned with a longitudinal direction of the protection cup <NUM>. As shown in <FIG>, the protection cup <NUM> may comprise three longitudinal fractal elements <NUM>. Alternatively or additionally, the protection cup <NUM> may comprise a different number of longitudinal fractal elements, such as two or fewer and/or greater than three.

Each of the plurality of transverse fractal elements <NUM> is aligned with a transverse direction of the protection cup <NUM>. As shown in <FIG>, the protection cup <NUM> may comprise three transverse fractal elements <NUM>. Alternatively or additionally, the protection cup <NUM> may comprise a different number of transverse fractal elements, such as two or fewer and/or greater than three.

In the example shown in <FIG>, the plurality of transverse fractal elements <NUM> are aligned in a perpendicular relationship to the plurality of longitudinal fractal elements <NUM>. Together, longitudinal fractal elements <NUM> and transverse fractal elements <NUM> may divide the inner surface <NUM> into a plurality of regions <NUM>. Each of the plurality of regions <NUM> may be in the shape of a rectangle. In some examples, one or more of the regions <NUM> may be of other shapes, such as square, circle and/or the like. The number of the regions <NUM> may be based on, for example, the size of the cup. As shown in <FIG>, the inner surface <NUM> is divided into sixteen regions (including partial regions depicted on the top-left corner, top-right corner, bottom-left corner, and bottom-right corner) by the longitudinal fractal elements <NUM> and transverse fractal elements <NUM>. Alternatively or additionally, the number of regions may be less than or more than sixteen.

In the example shown in <FIG>, a plurality of additional fractal elements <NUM> are disposed within at least one of the plurality of regions <NUM> and protrude from the inner surface <NUM>. Each of the additional fractal elements <NUM> forms one or more patterns, such as a pattern similar to the capital letter "H" in the English alphabet (hence also referred to as H-shaped fractal elements).

In the example shown in <FIG>, each of the additional fractal elements <NUM> may comprise one or more longitudinal segments <NUM>, transverse segments <NUM>, and leg segments <NUM>. Alternatively or additionally, additional fractal elements <NUM> may take alternative shapes and/or include one or more longitudinal segment <NUM>, transverse segments <NUM>, and leg segments <NUM>. In some examples, the additional fractal elements <NUM> may take the form of other letters, such as the letters L, K, F, E, and/or the like. Whereas in other examples, the additional fractal elements <NUM> may take the form of multi-side shapes, such as triangles, squares, pentagons, and/or the like. In yet further examples, the additional fractal elements <NUM> may take a random or semi-random pattern.

Referring back to the example shown in <FIG>, each longitudinal segment <NUM> is the "horizontal bar" in the middle of the capital letter "H" pattern formed by each of the additional fractal elements <NUM>. As illustrated in <FIG>, the longitudinal segment <NUM> of each additional fractal elements <NUM> is parallel to the plurality of longitudinal fractal elements <NUM> and aligned with the longitudinal direction of the protection cup <NUM>.

In the example shown in <FIG>, two or more of neighboring additional fractal elements <NUM> may be connected through the longitudinal segment <NUM> in the longitudinal direction. For example, as shown in <FIG>, the longitudinal segment 113A of fractal element 111A is connected to the longitudinal segment 113B of fractal element 111B. Additionally or alternatively, at least two of neighboring additional fractal elements are not connected through the longitudinal segment. For example, <FIG> illustrates an example embodiment where some neighboring additional fractal elements are not connected to each other, details of which are described hereinafter.

The transverse segments <NUM> are the "vertical bars" in the capital letter "H" pattern formed by each of the additional fractal elements <NUM>. As illustrated in <FIG>, the pair of transverse segments <NUM> of each additional fractal elements <NUM> are parallel to the plurality of transverse fractal elements <NUM> and aligned with a transverse direction of the protection cup <NUM>.

The leg segments <NUM> of each of the plurality of additional fractal elements <NUM> are disposed at end points of the transverse segments <NUM>. The leg segments <NUM> are parallel to the plurality of longitudinal fractal elements <NUM> and aligned with the longitudinal direction of the protection cup <NUM>. In other words, the leg segments <NUM> are parallel to the longitudinal segment <NUM>. As illustrated in <FIG>, the leg segments <NUM> are at a same distance from the corresponding longitudinal segment <NUM> in the corresponding additional fractal elements <NUM>. In some embodiments, the leg segments may be at different distances from the corresponding longitudinal segment.

In the example shown in <FIG>, the plurality of additional fractal elements <NUM> have the same size. In other words, the plurality of additional fractal elements <NUM> may have the same size for the longitudinal segment <NUM>, the same size for transverse segments <NUM>, and the same size for leg segments <NUM>. In some embodiments, one or more of the plurality of additional fractal elements <NUM> may have different sizes.

In the example shown in <FIG>, each of the plurality of additional fractal elements <NUM> may be disposed on the same position relative to its corresponding region. In some embodiments, the plurality of additional fractal elements <NUM> may be disposed on different positions relative to their corresponding regions.

In the example shown in <FIG>, each of the plurality of regions <NUM> may include only one of the additional fractal elements <NUM>. In some embodiments, more than one fractal element may be disposed within each of the plurality of regions <NUM>.

Referring now to <FIG>, other views of the example protection cup <NUM> for a hearing protection device are shown. As shown in <FIG> and as described above, the plurality of longitudinal fractal elements <NUM> and the plurality of transverse fractal elements <NUM> may divide the inner surface <NUM> of the protection cup <NUM> into a plurality of regions <NUM>. As shown in <FIG> and as described above, each of the additional fractal elements <NUM> may comprise a longitudinal segment <NUM>, a pair of transverse segments <NUM>, and four leg segments <NUM>.

<FIG> illustrate that the inner surface <NUM> of the protection cup <NUM> may comprise a protruding portion <NUM>. In various embodiments of the present disclosure, the plurality of additional fractal elements <NUM> are disposed on the protruding portion <NUM> of the inner surface <NUM> of the protection cup <NUM>. As described above and further illustrated in the various analyses described below, disposing the plurality of additional fractal elements <NUM> on the protruding portion <NUM> of the inner surface <NUM> influence and/or improves, in some examples, noise attenuation and other performance of the hearing protection device. Example analyses are described in details in connection with <FIG>.

<FIG> further illustrate that the inner surface <NUM> of the protection cup <NUM> may comprise a curved portion <NUM> surrounding the protruding portion <NUM>. In some embodiments, a plurality of ribs <NUM> are disposed on the curved portion <NUM> of the inner surface <NUM> of the protection cup <NUM>, and may provide structural integrity support for the protection cup <NUM>.

<FIG> further illustrate additional and/or alternative views of the example protection cup <NUM>. In particular, <FIG> illustrates a back view of the protection cup <NUM>; <FIG> illustrates a front view of the protection cup <NUM>; <FIG> illustrates a top view of the protection cup <NUM>; <FIG> illustrates a bottom view of the protection cup <NUM>; and <FIG> illustrates an isometric view of the protection cup <NUM>.

Referring now to <FIG>, cross-sectional views of example protection cups in accordance with various embodiments of the present disclosure are shown. In particular, <FIG> illustrate example measurements of example protection cups.

Referring now to <FIG>, cross-sectional views of an example protection cup <NUM> in accordance with various embodiments of the present disclosure are illustrated.

The example protection cup <NUM> may comprise a protruding portion <NUM> surrounded by a curved portion <NUM>. As shown in <FIG>, a center of the reference plane <NUM> (defined by the edges of the curved portion <NUM>) may be at a distance D1 to an outer edge of the curved portion <NUM>. In some embodiments, the distance D1 may be in the range of <NUM> to <NUM>. In some embodiments (and as shown in <FIG>), the distance D1 is <NUM>. In some embodiments, other ranges and values may be used for D1.

The angle between a reference plane that is orthogonal to the protruding portion <NUM> and the reference plane <NUM> may be D2. In some embodiments, the angle D2 may be in the range of <NUM> degrees to <NUM> degrees. In some embodiments (and as shown in <FIG>), the angle D2 is <NUM> degrees. In some embodiments, other ranges and values may be used for D2.

A distance between the protruding portion <NUM> and the reference plane <NUM> may be D3. In some embodiments, the distance D3 may be in the range of <NUM> to <NUM>. In some embodiments (and as shown in <FIG>), the distance D3 is <NUM>. In some embodiments, other ranges and values may be used for D3.

A width of the protruding portion <NUM> may be D4. In some embodiments, the distance D4 may be in the range of <NUM> to <NUM>. In some embodiments, the distance D4 is preferably <NUM>. In some embodiments, other ranges and values may be used for D4.

The protrusion depth of the protruding portion <NUM> may be D6. In some embodiments, the distance D6 may be in the range of <NUM> to <NUM>. In some embodiments (and as shown in <FIG>), the distance D6 is <NUM>. In some embodiments, other ranges and values may be used for D6.

A distance between the protruding portion <NUM> and reference plane <NUM> may be D11. In some embodiments, the distance D11 may be in the range of <NUM> to <NUM>. In some embodiments (and as shown in <FIG>), the distance D11 is <NUM>. In some embodiments, other ranges and values may be used for D11.

From the cross-sectional view as shown in <FIG>, a radius from an imaginary center of the protection cup <NUM> to the protruding portion <NUM> may be D5. From the cross-sectional view as shown in <FIG>, a radius from an imaginary center of the protection cup <NUM> to the protruding portion <NUM> may be D7. In some embodiments, the value of D5 may be <NUM>. In some embodiments, the value of D7 may be <NUM>. In some embodiments, other values for D2 and/or D5 may be used.

<FIG> illustrate cross-sectional views of an example protection cup <NUM> in accordance with various embodiments of the present disclosure.

Similar to the protection cup <NUM> illustrated in <FIG>, the protection cup <NUM> may comprise a protruding portion <NUM> and a curved portion <NUM>. The protection cup <NUM> may also have similar measurements as protection cup <NUM>, except measurements related to the belly portion <NUM>, as described below.

As shown in <FIG>, the protection cup <NUM> further comprises a belly portion <NUM> that is further protruding from the protruding portion <NUM>. In this regard, D5 and D7 of the protection cup <NUM> as shown in <FIG> may be different from D5 and D7 of the protection cup <NUM> as shown in <FIG>. For example, the D5 of protection cup <NUM> may be <NUM>. As another example, the D7 of the protection cup <NUM> may be <NUM>. In some embodiments, other values for D2 and/or D5 of the protection cup <NUM> may be used. These differences may change the eigenfrequency and attenuation performance of the protection cups, as described in details hereinafter.

Referring now to <FIG>, example protection cups with different patterns formed by fractal elements are illustrated. Example performance analyses of these example protection cups are described in connection with <FIG>.

Referring now to <FIG>, an example protection cup <NUM> is shown. The protection cup <NUM> comprises a plurality of fractal elements disposed on an inner surface <NUM> of the protection cup <NUM>. The plurality of fractal elements may include a plurality of first fractal elements (for example, the plurality of longitudinal fractal elements <NUM>), a plurality of second fractal elements (for example, the plurality of transverse fractal elements <NUM>), and a plurality of additional fractal elements <NUM>.

In the example shown in <FIG>, each of the plurality of longitudinal fractal elements <NUM> is aligned with a longitudinal direction of the protection cup <NUM>. Each of the plurality of transverse fractal elements <NUM> is aligned with a transverse direction of the protection cup <NUM>. As shown in <FIG>, the plurality of transverse fractal elements <NUM> are aligned in a perpendicular relationship to the plurality of longitudinal fractal elements <NUM>. Together, longitudinal fractal elements <NUM> and transverse fractal elements <NUM> may divide the inner surface <NUM> into a plurality of regions <NUM>, similar to the longitudinal fractal elements <NUM> and transverse fractal elements <NUM> described above in connection with <FIG>.

A plurality of additional fractal elements <NUM> are disposed on the inner surface <NUM> of the protection cup <NUM>, and particularly, within each of the regions <NUM>. The additional fractal elements <NUM> are similar to the additional fractal elements <NUM> described above in connection with <FIG>, and form patterns similar to the capital letter "H" in the English alphabet. Comparing the additional fractal elements <NUM> in <FIG> and the additional fractal elements <NUM> in <FIG>, it is noted that each of the additional fractal elements <NUM> is connected to no more than one other neighboring additional fractal element in the longitudinal direction via the longitudinal segment <NUM>. For example, the additional fractal element 505A and the additional fractal element 505B are connected through their respective longitudinal segment 506A and 506B. The additional fractal element 505A is not connected to the additional fractal element 505C.

Referring now to <FIG>, an example protection cup <NUM> is shown. The protection cup <NUM> comprises a plurality of fractal elements disposed on an inner surface <NUM> of the protection cup <NUM>. The plurality of fractal elements may comprise a plurality of longitudinal fractal elements <NUM>, a plurality of transverse fractal elements <NUM>, and a plurality of additional fractal elements <NUM>, similar to the plurality of longitudinal fractal elements <NUM>, the plurality of transverse fractal elements <NUM>, and the plurality of additional fractal elements <NUM> described above in connection with <FIG>.

In the example shown in <FIG>, the plurality of fractal elements may include one or more corner fractal elements <NUM>. The corner fractal elements <NUM> are disposed on the corners of the inner surface <NUM> of the protection cup <NUM>. In some examples, each of the corner fractal elements <NUM> is at forty-five degrees from one of the longitudinal fractal elements <NUM> and one of the transverse fractal elements <NUM>. Additionally or alternatively, one or more of the plurality of the corner fractal elements <NUM> are at a different degree than forty-five degrees from one of the longitudinal fractal elements <NUM> and/or one of the transverse fractal elements <NUM>.

Referring now to <FIG>, various example patterns formed by fractal elements are illustrated.

Referring now to <FIG>, an example protection cup <NUM> is shown. The protection cup <NUM> comprises a plurality of fractal elements disposed on the inner surface <NUM> of the protection cup <NUM>. The plurality of fractal elements comprise a plurality of longitudinal fractal elements <NUM> and a plurality of transverse fractal elements <NUM>. Each of the plurality of longitudinal fractal elements <NUM> is aligned with a longitudinal direction of the protection cup <NUM>. Each of the plurality of transverse fractal elements <NUM> is aligned with a transverse direction of the protection cup <NUM>. The plurality of transverse fractal elements <NUM> are aligned in a perpendicular relationship to the plurality of longitudinal fractal elements <NUM>.

Together, the longitudinal fractal elements <NUM> and the transverse fractal elements <NUM> may form an "H-tree" structure on the inner surface <NUM> of the protection cup <NUM>. The "H-tree" structure may comprise various levels of H-tree patterns formed by the fractal elements. For example, the longitudinal fractal element 702A and the transverse fractal elements 703A, 703B may form a first-level H-tree pattern <NUM>. As shown, the first-level H-tree pattern <NUM> resembles the shape of a capital letter "H" in the English alphabet.

Further, a plurality of first-level H-tree patterns may be connected by the longitudinal fractal elements <NUM> and the transverse fractal elements <NUM>, and together they form a second-level H-tree pattern, such as the second-level H-tree pattern <NUM>. As shown in <FIG>, the second-level H-tree pattern <NUM> also resembles the shape of a capital letter "H" in the English alphabet.

In some embodiments, the relationship between the size of the first-level H-tree pattern <NUM> and the size of the second-level H-tree pattern <NUM> is as follows: <MAT> where S<NUM> is the size of the first-level H-tree pattern <NUM>, S<NUM> is the size of the second-level H-tree pattern <NUM>, and k is the sizing ratio. In some embodiments, the sizing ratio k equals to the square root of two (i.e. <MAT>). For example, the length of the transverse fractal element 703C may be <MAT> times the length of transverse fractal element 703A. In some embodiments, the sizing ratio k may have other values, including, for example, golden ratio (<NUM>), silver ratio (<NUM>), or bronze ratio <NUM>. Similar sizing calculations may also apply to the H-tree patterns as described in connection with <FIG>.

Referring back to <FIG>, additional levels of H-tree patterns may be formed by the longitudinal fractal elements <NUM> and the transverse fractal elements <NUM>. For example, second-level H-tree patterns may be connected by the transverse fractal elements 703D and 703E to form a third-level H-tree pattern. The size of the third-level H-tree pattern may be calculated based on the size of the second-level H-tree pattern and the sizing ratio, similar to those described above in connection with the second-level H-tree pattern and the first-level H-tree pattern.

Referring now to <FIG>, an example protection cup <NUM> is shown. The protection cup <NUM> includes a plurality of fractal elements disposed on the inner surface <NUM> of the protection cup <NUM>. The plurality of fractal elements comprise a plurality of longitudinal fractal elements <NUM> and a plurality of transverse fractal elements <NUM>. Each of the plurality of longitudinal fractal elements <NUM> is aligned with a longitudinal direction of the protection cup <NUM>. Each of the plurality of transverse fractal elements <NUM> is aligned with a transverse direction of the protection cup <NUM>. The plurality of transverse fractal elements <NUM> are aligned in a perpendicular relationship to the plurality of longitudinal fractal elements <NUM>.

As shown in <FIG>, the plurality of longitudinal fractal elements <NUM> and the plurality of transverse fractal elements <NUM> may form a plurality of H-tree patterns at various levels, and at least one H-tree pattern is not connected to any other H-tree pattern at the same level. For example, the plurality of longitudinal fractal elements <NUM> and the plurality of transverse fractal elements <NUM> may form a first-level H-tree pattern <NUM>, a second-level H-tree pattern <NUM>, and the third-level H-tree pattern <NUM>. The third-level H-tree pattern <NUM> is not connected to any other H-tree pattern at the third level (for example, the third-level H-tree pattern <NUM>').

Additionally or alternatively, the plurality of longitudinal fractal elements and transverse fractal elements may form one or more H-tree patterns that are not connected to the same or any other level of H-tree patterns. Additionally or alternatively, the plurality of longitudinal fractal elements and transverse fractal elements may form one or more H-tree patterns that are connected to one or more H-tree pattern at a different level (for example, a first-level H-tree pattern may be connected to a separated second-level H-tree via the plurality of longitudinal fractal elements and/or transverse fractal elements).

Similar to the longitudinal fractal elements <NUM> and the transverse fractal elements <NUM> described above in connection with <FIG>, the plurality of longitudinal fractal elements <NUM> are aligned in a perpendicular relationship to the plurality of transverse fractal elements <NUM>, and together they may form one or more levels of H-tree patterns.

In comparison with the fractal elements as shown in <FIG>, the fractal elements in <FIG> further includes a central longitudinal fractal element <NUM> and a central transverse fractal element <NUM>. The central longitudinal fractal element <NUM> is disposed at the central position in the transverse direction on the inner surface <NUM>, and is parallel to the longitudinal fractal elements <NUM>. The central transverse fractal element <NUM> is disposed at the central position in the longitudinal direction on the inner surface <NUM>, and is parallel to the transverse fractal elements <NUM>.

Similar to the spatial relationship between the transverse fractal elements <NUM> and the longitudinal fractal elements <NUM> described above in connection with <FIG>, the plurality of transverse fractal elements <NUM> are aligned in a perpendicular relationship to the plurality of longitudinal fractal elements <NUM>, and together they may form one or more levels of H-tree patterns. The plurality of fractal elements in <FIG> further comprise a central longitudinal fractal element <NUM> and a central transverse fractal element <NUM>, similar to the central longitudinal fractal element <NUM> and the central transverse fractal element <NUM> described above in connection with <FIG>.

While the fractal elements as illustrated in <FIG> may form more levels of H-tree patterns than the fractal elements as illustrated in <FIG>, it is noted that the present disclosure is not limited to the fractal elements forming a particular level of H-tree pattern.

Referring now to <FIG>, an example protection cup <NUM> is shown. The protection cup <NUM> comprises a plurality of fractal elements disposed on an inner surface <NUM> of the protection cup <NUM>. For example, the plurality of fractal elements may comprise a plurality of longitudinal fractal elements <NUM> and a plurality of transverse fractal elements <NUM>. Each of the plurality of longitudinal fractal elements <NUM> is aligned with a longitudinal direction of the protection cup <NUM>. Each of the plurality of transverse fractal elements <NUM> is aligned with a transverse direction of the protection cup <NUM>. As shown in <FIG>, the plurality of transverse fractal elements <NUM> are aligned in a perpendicular relationship to the plurality of longitudinal fractal elements <NUM>.

The plurality of longitudinal fractal elements <NUM> and the plurality of transverse fractal elements <NUM> may divide the inner surface <NUM> of the protection cup <NUM> into a plurality of regions <NUM>. In some embodiments, the regions <NUM> are in the shape of rectangles. In some examples, one or more regions <NUM> may have a shape different from rectangle. In some embodiments, the regions <NUM> are of the same size. In some examples, the regions <NUM> may be of different sizes.

Referring now to <FIG>, an example protection cup <NUM> is shown. The protection cup <NUM> comprises a plurality of fractal elements disposed on an inner surface <NUM> of the protection cup <NUM>. For example, the plurality of fractal elements may comprise a plurality of longitudinal fractal elements <NUM>, a plurality of transverse fractal elements <NUM>, and a plurality of diagonal fractal elements <NUM>. Each of the plurality of longitudinal fractal elements <NUM> is aligned with a longitudinal direction of the protection cup <NUM>. Each of the plurality of transverse fractal elements <NUM> is aligned with a transverse direction of the protection cup <NUM>.

As shown in <FIG>, the plurality of transverse fractal elements <NUM> are aligned in a perpendicular relationship to the plurality of longitudinal fractal elements <NUM>. In some examples, each of the plurality of diagonal fractal elements <NUM> is at forty-five degrees from one of the longitudinal fractal elements <NUM> and one of the transverse fractal elements <NUM>. In some examples, one or more of the plurality of diagonal fractal elements <NUM> are at a different degree than forty-five degrees from one of the longitudinal fractal elements <NUM> and/or one of the transverse fractal elements <NUM>.

The plurality of longitudinal fractal elements <NUM>, the plurality of transverse fractal elements <NUM>, and the plurality of diagonal fractal elements <NUM> divide the inner surface <NUM> of the protection cup <NUM> into a plurality of regions <NUM>. In some embodiments, the regions <NUM> are in the shape of triangles. In some examples, one or more regions <NUM> may have a shape different from triangle. In some embodiments, the regions <NUM> are of the same size, and neighboring regions may share an edge. For example, as shown in <FIG>, the region 1205A and region 1205B share an edge that is part of one of the transverse fractal elements <NUM>. In some examples, the regions <NUM> may be of different sizes.

Referring now to <FIG>, an example protection cup <NUM> is shown. The protection cup <NUM> comprises a plurality of fractal elements <NUM> disposed on an inner surface <NUM> of the protection cup <NUM>. As shown in <FIG>, the plurality of fractal elements <NUM> may divide the inner surface <NUM> into a plurality of hexagon regions <NUM>. In some embodiments, three of the plurality of hexagon regions <NUM> meet at a vertex. For example, hexagon region 1303A, hexagon region 1303B, and hexagon region 1303C meets at vertex <NUM>. As such, the plurality of fractal elements <NUM> are in the pattern of a hexagonal tiling.

In some examples, the plurality of fractal elements <NUM> may form the pattern of a trihexagonal tiling. In such examples, the plurality of fractal elements <NUM> may divide the inner surface <NUM> of the protection cup <NUM> into equilateral triangle regions and regular hexagon regions. The equilateral triangle regions and regular hexagon regions are arranged so that each hexagon region is surrounded by triangle regions, and each triangle region is surrounded by hexagon regions.

In various embodiments of the present disclosure, the plurality of fractal elements may form other patterns. As examples, such patterns may include Peano Curve, Hilbert Curve, Moore Curve, Fibonacci Word Fractal, and/or the like. In some embodiments, the pattern may be fractal or cut-through.

While example patterns are described above, it is noted that the present disclosure is not limited to these examples, and the fractal elements may form other patterns without deviating from the scope of the present disclosure. In some embodiments, the pattern may be triangular, rectangular, polygonal, and/or circular. In some embodiments, the pattern may include H-shaped fractal elements having different sizes. In some embodiments, the plurality of fractal elements may form different patterns on the inner surface of the protection cup. For example, the different patterns may be grouped in portions or quadrants, and each portion or quadrant may have a same or different pattern formed by fractal elements.

As described in details hereinafter, various analyses illustrate the effects that the shape and size of the fractal elements may have on the performance of hearing protection device. In particular, eigenfrequency analysis insertion loss analysis are performed on example apparatuses that embody embodiments of the present disclosure. These analyses show that various embodiments of the present disclosure increase and/or manipulate noise attenuation and improve performance of hearing protection device.

<FIG> illustrate example eigenfrequency and attenuation analyses, including, for example, insertion loss analysis. In conducting these analyses, four (<NUM>) sets of example apparatuses are used. Each set of example apparatuses embodies features from one of the protection cup <NUM>, the protection cup <NUM>, the protection cup <NUM>, and the protection cup <NUM>. There are twelve (<NUM>) example apparatuses within each set (Mode No. <NUM> to <NUM>), each having a different outer shape. Example apparatuses with the same mode number in different sets have the same outer shape. Further, cushion inside the example apparatuses are removed, and the apparatuses are stiffly fixed on a hard surface.

While these example apparatuses are described, it is noted that the scope of the present disclosure is not limited to these particular example apparatuses. Results of the eigenfrequency analysis and the attenuation analysis indicate that embodiments of the present disclosure improve noise attenuation.

<FIG> illustrate the results of eigenfrequency analysis on the performance of example apparatuses embodying the present disclosure. Here, eigenfrequency (or "natural frequency") refers to the frequency or frequencies at which the hearing protection device is prone to vibrate. In some examples, the results of eigenfrequency analysis as shown may be based on, for example, computer simulations that include computer modeling of example apparatuses described above, and may provide indications on the performance of example apparatuses in real life.

Referring to <FIG>, chart <NUM> illustrates the example eigenfrequencies of the four (<NUM>) sets of example apparatuses described above. In particular, line <NUM> shows the eigenfrequencies of the set of example apparatuses that embody features from protection cup <NUM> as described above. Line <NUM> shows the example eigenfrequencies of the set of example apparatuses that embody features from protection cup <NUM> as described above. Line <NUM> shows the example eigenfrequencies of the set of example apparatuses that embody features from protection cup <NUM> as described above. Line <NUM> shows the example eigenfrequencies of the set of example apparatuses that embody features from protection cup <NUM> as described above.

Referring to <FIG>, chart <NUM> illustrates the example eigenfrequencies difference ratios of the four sets of example apparatuses described above. In particular, line <NUM> shows the example eigenfrequencies difference ratios between the set of example apparatuses that embody features from protection cup <NUM> and the set of example apparatuses that embody features from protection cup <NUM>. Line <NUM> shows the eigenfrequencies difference ratios between the set of example apparatuses that embody features from protection cup <NUM> and the set of example apparatuses that embody features from protection cup <NUM>. Line <NUM> shows the eigenfrequencies difference ratios between the set of example apparatuses that embody features from protection cup <NUM> and the set of example apparatuses that embody features from protection cup <NUM>.

As can be seen from <FIG>, the protection cup <NUM> and the protection cup <NUM> result in similar eigenfrequencies of the example hearing protection devices. For example, line <NUM> of <FIG> (which illustrates the eigenfrequencies difference ratios between protection cup <NUM> and protection cup <NUM>) centers around <NUM>%.

In contrast, the protection cup <NUM> and the protection cup <NUM> result in different eigenfrequencies of the example hearing protection devices. For example, there is few overlap between line <NUM> and line <NUM> of <FIG>. As described above, the fractal elements of the protection cup <NUM> and the fractal elements of the protection cup <NUM> form different patterns. Therefore, <FIG> illustrate that fractal elements disposed on the example protection cup can have an impact on the acoustics characteristics of the hearing protection device.

<FIG> illustrate the attenuation analysis on the performance of example apparatuses embodying the present disclosure and its result. Referring now to <FIG>, a schematic diagram illustrating the model that is used for attenuation analysis is shown. In particular, sound pressure is evaluated over the area <NUM>, which has a diameter of ½ inch (i.e. standard measurement microphone). For the attenuation analysis, acoustic attenuation is defined as: <MAT> where P<NUM>amp is the pressure amplitude for the model without protection cup, and P<NUM>amp is the pressure amplitude for the model with protection cup.

Referring now to <FIG>, results of the attenuation analysis on the set of the example apparatuses are shown. Such attenuation analysis includes, for example, insertion loss (which indicates the loss of noise signal power). In some examples, the results of attenuation analysis as shown may be based on, for example, computer simulations that include computer modeling of example apparatuses described above, and may provide indications on the performance of example apparatuses in real life.

In particular, <FIG> illustrates the insertion loss at different frequencies. Line <NUM> shows the insertion loss at different frequencies for the set of example apparatuses that embody features from protection cup <NUM>. Line <NUM> shows the insertion loss at different frequencies for the set of example apparatuses that embody features from protection cup <NUM>. Line <NUM> shows the insertion loss at different frequencies for the set of example apparatuses that embody features from protection cup <NUM>. Line <NUM> shows the insertion loss at different frequencies for the set of example apparatuses that embody features from protection cup <NUM>.

<FIG> illustrates the differences in insertion loss of the four sets of example apparatuses described above. In particular, line <NUM> illustrates the differences in insertion loss between the set of example apparatuses that embody features from protection cup <NUM> and the set of example apparatuses that embody features from protection cup <NUM>. Line <NUM> illustrates the differences in insertion loss between the set of example apparatuses that embody features from protection cup <NUM> and the set of example apparatuses that embody features from protection cup <NUM>. Line <NUM> illustrates the differences in insertion loss between the set of example apparatuses that embody features from protection cup <NUM> and the set of example apparatuses that embody features from protection cup <NUM>.

As shown in <FIG>, the insertion loss of the set of example apparatuses that embody features from protection cup <NUM> become worse (i.e. less noise being reduced) at the frequency range <NUM> (as shown by line <NUM>), while the insertion loss of the set of example apparatuses that embody features from protection cups <NUM> and <NUM> become better at frequency range <NUM> (as shown by lines <NUM> and <NUM>). In some example apparatus embodying features from the protection cup <NUM>, there is no fractal element. Therefore, <FIG> demonstrates that example protection cups in accordance with embodiments of the present disclosure (including protection cup <NUM>, protection cup <NUM>, and protection cup <NUM>) improves noise attenuation, including, for example, insertion loss at least due to the addition of the fractal elements.

<FIG> illustrate example insertion loss analyses. In conducting these analyses, three apparatuses are used. The first example apparatus is a hearing protection cup without any fractal element, similar to the protection cup <NUM> (as shown in <FIG>). The second example apparatus embodies features from the example protection cup <NUM> as shown in <FIG>. The third example apparatus embodies features from the example protection cup <NUM> as shown in <FIG>. In some examples, the results of insertion loss analysis as shown in <FIG> may be based on, for example, computer simulations that include computer modeling of example apparatuses described above, and may provide indications on the performance of example apparatuses in real life.

Referring now to <FIG>, the chart <NUM> illustrates the example attenuation of the example apparatuses described above. In particular, line <NUM> illustrates the attenuation performance of the first example apparatus (i.e. without fractal elements). Line <NUM> illustrates the attenuation performance of the second example apparatus (i.e. example protection cup <NUM> as shown in <FIG>). Line <NUM> illustrates the attenuation performance of the third example apparatus (i.e. example protection cup <NUM> as shown in <FIG>).

As illustrated the chart <NUM>, the attenuation of hearing protection device can be manipulated by the fundamental vibration mode of the hearing protection device via the addition of fractal elements. In particular, lines <NUM> and <NUM>, in comparison to line <NUM>, indicate that fundamental vibration mode of the hearing protection device is adjusted after the fractal elements are implemented on the hearing protection cup. The higher the fundamental vibration mode of the hearing protection device, the higher the attenuation level that the hearing protection device can achieve in the concerned frequency range. In various embodiments, the attenuation level can be manipulated in the concerned frequency range from <NUM> to <NUM>.

Further, by comparing line <NUM> and line <NUM>, the chart <NUM> shows that the specific attenuation level of hearing protection device can be adjusted by varying the shape/dimension of the fractal elements.

Referring now to <FIG>, chart <NUM> further illustrates the insertion loss analyses of the first example apparatus and the third example apparatus in real life. Here, insertion loss refers to the loss of noise due to hearing protection device. As shown in <FIG>, the insertion loss provided by the third example apparatus (i.e. as shown by line <NUM>) is superior in comparison to the first example apparatus (i.e. as shown by line <NUM>). The affected frequency range is from <NUM> to <NUM>, and the maximum attenuation change can be up to <NUM> dB.

While the present disclosure is not limited to any particular frequency range, it is noted that the frequency range of <NUM> to <NUM> is of particular interest to the universal rating methods for hearing protection devices, such as Noise Reduction Rating (NRR), SNR (Single Number Rating), and SLC (Sound Level Conversion). Thus, together with considerable attenuation level that can be achieved as shown in <FIG>, the attenuation of the hearing protection device can be manipulated in a sizable range via, for example, the fractal elements described above to meet the attenuation ratings of the hearing protection device. In other words, various embodiments include a method for manipulating earmuff cup attenuation in a sizable range via the fractal elements to meet the attenuation ratings of the hearing protection device.

Embodiments of the present disclosure may be implemented as methods for manufacturing protection cup and hearing protection device in accordance with various embodiments of the present disclosure.

Referring now to <FIG>, an example protection cup <NUM> manufactured through a single molding process is shown. The protection cup <NUM> may be made of, for example but not limited to, rigid plastic or resin material. A liquid form of the material may be shaped using a rigid frame ("a mold") with hollowed-out blocks. The liquid hardens inside the mold and adopts its shape, resulting the protection cup <NUM> as shown in <FIG>.

In accordance with various embodiments of the present disclosure, an example method for manufacturing protection cup <NUM> may include molding a plurality of longitudinal fractal elements on an inner surface of the protection cup, molding a plurality of transverse fractal elements on the inner surface of the protection cup, and molding a plurality of additional fractal elements on the inner surface of the protection cup.

As described above, the plurality of transverse fractal elements are in perpendicular arrangements to the plurality of longitudinal fractal elements, forming a plurality of regions on the inner surface. Each of the plurality of additional fractal elements are within one of the plurality of the regions on the inner surface.

As described above, each of the plurality of additional fractal elements molded through the example manufacturing process may comprise a longitudinal segment and a pair of transverse segments. In some embodiments, the longitudinal segment is parallel to the plurality of longitudinal fractal elements, and the pair of transverse segments are parallel to the plurality of transverse fractal elements. In some examples, two or more of the plurality of additional fractal elements molded through the example manufacturing process are connected through longitudinal segments of the two or more of the plurality of additional fractal elements.

As described above, each of the plurality of additional fractal elements molded through the example manufacturing process further comprises a plurality of leg segments. Each of the leg segments is molded at an end point of the transverse segments, and the leg segments are molded parallel to the plurality of longitudinal fractal elements.

As described above, the plurality of additional fractal elements molded through the example manufacturing process may be of the same size.

In accordance with various embodiments of the present disclosure, the example method for manufacturing protection cup <NUM> also includes forming a protruding portion on the inner surface of the protection cup. In some embodiments, plurality of additional fractal elements are molded on the protruding portion of the inner surface of the protection cup.

In accordance with various embodiments of the present disclosure, the example method for manufacturing protection cup <NUM> also includes forming a curved portion on the inner surface surrounding the protruding portion, and molding a plurality of ribs on the curved portion of the inner surface of the protection cup.

Referring now to <FIG>, example components for manufacturing a protection cup through an example method in accordance with various embodiments of the present disclosure are shown. The fractal element panel <NUM> (as shown in <FIG>) and the protection cup <NUM> (as shown in <FIG>) may be made of, for example but not limited to, rigid plastic or resin material. The fractal element panel <NUM> comprises a plurality of longitudinal fractal elements, a plurality of transverse fractal elements, and a plurality of additional fractal elements. As described above, the plurality of transverse fractal elements may be perpendicular to the plurality of longitudinal fractal elements, forming a plurality of regions having a plurality of additional fractal elements. The protection cup may be manufactured by attaching the fractal element panel <NUM> with ribs (as shown in <FIG>) to the protection cup <NUM> (as shown in <FIG>).

Claim 1:
A protection cup (<NUM>) for a hearing protection device, comprising:
an outer surface (<NUM>);
an inner surface (<NUM>) on an opposite side from the outer surface (<NUM>); and
a plurality of fractal elements disposed on the inner surface (<NUM>), wherein the plurality of fractal elements comprises:
a plurality of first fractal elements (<NUM>) protruding from the inner surface (<NUM>) of the protection cup (<NUM>);
a plurality of second fractal elements (<NUM>) protruding from the inner surface (<NUM>) of the protection cup (<NUM>), wherein the plurality of first fractal elements (<NUM>) and the plurality of second fractal elements (<NUM>) form a plurality of regions on the inner surface (<NUM>); and
a plurality of additional fractal elements (<NUM>) disposed within at least one of the plurality of regions on the inner surface (<NUM>), wherein each of the plurality of additional fractal elements (<NUM>) is an H-shaped fractal element.