Balanced armature receiver diaphragm and balanced armature receiver

Abstract

The present invention relates to a balanced armature receiver diaphragm and a balanced armature receiver. The diaphragm comprises a leaf having a mass concentration region located at or near a central portion of the leaf, the mass concentration region having an area density greater than an area density of other portions of the leaf, wherein the mass concentration region shifts a bending mode frequency of the leaf to a frequency lower than a bending mode frequency of the leaf without the mass concentration region.

Description

Technical Field

[0001] This disclosure generally relates to balanced armature (BA) receivers, and more specifically to balanced armature receivers with improved frequency response, diaphragms and components for such balanced armature receivers. Background Technology

[0002] Balanced armature receivers (also referred to herein as “receivers” and “BAs”) capable of generating sound output signals in response to electronic audio signals are commonly used in hearing devices such as hearing aids, wired and wireless headphones, and true wireless stereo (TWS) devices. BA receivers typically consist of a cup- and lid-shaped housing that encloses a diaphragm, which divides the interior of the housing into a rear volume and a front volume. An electromagnet includes an electric coil disposed around an armature (also referred to herein as a “reed”) having a free end portion movably disposed between permanent magnets held by a yoke. A drive rod or other linkage mechanically connects the reed to a movable portion of the diaphragm, called a blade. When an electrical signal (representing sound) is applied to the coil, the reed vibrates between the magnets; otherwise, the reed remains balanced between the magnets. The moving diaphragm exhausts sound through the sound port of the housing via the front volume.

[0003] A graph of the sound pressure level (SPL) output by a typical BA receiver, measured in decibels (dB), versus the frequency, measured in hertz (Hz), is referred to in this paper as the “frequency response.” The acoustic output of a receiver is typically non-uniform across all audible frequencies and includes multiple amplitude peaks attributable to mechanical and acoustic resonances. Some frequency response peaks are primarily attributable to the user’s ear canal or the part of the hearing device that couples the receiver into the ear canal. Another peak is primarily attributable to the diaphragm, more specifically to the bending mode of the blades. This bending mode peak typically has a higher frequency than the peak attributable to the user’s ear.

[0004] Industry-standard ear simulators are frequently used to simulate receivers worn by users. One such simulator is specified by the International Electrotechnical Commission (IEC) standard 60318-4 and is known as the high-resolution 711 coupler. Other simulators can also be used to simulate receiver performance. Receiver performance is typically measured using the receiver coupled to the coupler, but when the receiver is actually integrated into the hearing device, the frequency response peaks may shift and other peaks may appear. This variation can usually be attributed to the acoustic output path or acoustic impedance created by the unique structure of the hearing device, among other factors.

[0005] In some receivers (e.g., in tweeters), high SPL peaks may exist at frequencies above the audible range for many users. These peaks can be attributed, among other reasons, to the bending patterns of the blades. For example, some people cannot hear frequencies above 18 kHz or lower. A diaphragm resonator can shift the resonance of these higher frequency peaks to a limited extent, but a single resonator may not be able to shift the resonance to frequencies perceptible to some. Therefore, receivers with improved frequency performance are desirable. Summary of the Invention

[0006] The present invention provides a balanced armature receiver diaphragm comprising: a blade, the blade including a substantially planar member having a material thickness between 0.03 mm and 0.07 mm and an effective modulus of not less than 30 gigapascals; the blade having a mass concentration region located at or near a central portion of the blade, the mass concentration region having an area density greater than that of other portions of the blade; wherein the mass concentration region is configured to reduce the bending mode frequency of the blade compared to the bending mode frequency of the blade without the mass concentration region.

[0007] The present invention also provides a balanced armature receiver comprising: a housing having a sound port; a diaphragm disposed in the housing and dividing the housing into a rear volume and a front volume, the front volume being acoustically coupled to the outside of the housing via the sound port, the diaphragm including blades having a mass concentration region located at or near the center of the blade, the mass concentration region having an area density greater than that of other portions of the blade; and a motor disposed in the housing and including a coil magnetically coupled to an armature having an end portion movably disposed between a plurality of magnets held by a yoke, the armature being coupled to the blades, wherein the armature moves the blades in response to an excitation signal applied to the coil, wherein the mass concentration region will shift the frequency response peak attributable primarily to the diaphragm to a frequency lower than the frequency response peak in the absence of the mass concentration region. Attached Figure Description

[0008] The objects, features, and advantages of this disclosure will become more fully apparent from the following detailed description and the appended claims, taken in conjunction with the accompanying drawings. The drawings depict only representative embodiments and should therefore not be construed as limiting the scope of the invention.

[0009] Figure 1 This is a cross-sectional view of a balanced armature receiver, which has a diaphragm with a mass concentration region.

[0010] Figure 2 This is a view of the balanced armature receiver, in which the cover has been removed, thereby exposing the diaphragm with an exposed mass concentration area.

[0011] Figure 3 This is another view of the balanced armature receiver, in which the cover has been removed, thus exposing the diaphragm with the mass concentration area.

[0012] Figure 4 yes Figure 3 A view of a balanced armature receiver having a cover with a sound port.

[0013] Figure 5 This is a cross-sectional view of a balanced armature receiver, in which the cover has been removed, thereby exposing the diaphragm with a mass concentration region.

[0014] Figure 6 yes Figure 5 A cross-sectional side view of the balanced armature receiver.

[0015] Figure 7 Frequency response diagrams for various diaphragm configurations are shown.

[0016] Figure 8 The first mode is shown, in which the blade, reed, and drive rod move together.

[0017] Figure 9 The bending mode of the first blade is shown.

[0018] Specific implementation method

[0019] Those skilled in the art will understand that: the accompanying drawings are for simplification and clarity and may therefore not be drawn to scale and may not include well-known features; unless otherwise stated, the order in which actions or steps occur may differ from or be performed simultaneously with the order described; and the terms and expressions used herein have the meanings understood by those skilled in the art, unless they are considered to have different meanings herein.

[0020] This disclosure relates generally to balanced armature receivers, and more specifically to balanced armature receivers having improved frequency response, and balanced armature receiver diaphragms and components for such receivers.

[0021] Figure 1 This is a representative BA receiver 100, which includes a diaphragm with an improved frequency response as described herein. The receiver includes a housing 110 and a diaphragm 120, the diaphragm 120 being disposed within the housing and dividing the interior of the housing into a front volume 112 and a rear volume 114. The front volume is acoustically coupled to the outside of the housing via an acoustic port located on a wall defining the front volume. Figure 1In this receiver implementation, the sound port 116 is located on the housing wall 111, parallel to the diaphragm. In other receiver implementations, the sound port may be located on the end wall 113 of the housing. Some receivers also include a nozzle (not shown) positioned above the sound port and connected to the housing wall.

[0022] A diaphragm typically comprises blades movable relative to a frame, the frame being disposed around the periphery of the blades. A gap separates the blades from the frame, and a flexible or elastic membrane covers this gap and allows the blades to move relative to the frame when the blades are driven by a motor of the receiver. The membrane may cover the entire blade and frame or only the area adjacent to the gap between the blades and frame. In embodiments where any orifices for mass reduction are present in the blades, the membrane may also cover such orifices. In some receiver implementations, the diaphragm includes a pressure relief vent through the blades, membrane, or frame to balance the pressure in the rear volume. In these implementations, the rear volume opens to the outside of the housing via a front volume. Alternatively, the pressure relief vent may be located in the wall defining the rear volume of the housing, wherein the rear volume opens directly to the outside of the housing rather than through the front volume.

[0023] Typically, the receiver includes a motor, which is housed within a housing to actuate the diaphragm. Figure 1 In the rear volume, the motor includes a coil 130 supported by a spool positioned around a portion of the armature 140. A free end portion 142 of the armature is movably positioned between permanent magnets 144 and 146, which are spaced apart by a yoke 150. The armature includes another portion 143 connected to the yoke. The free end portion of the armature is connected to the blade via a drive rod or other linkage 152. Figure 1 The armature in the receiver is a U-shaped spring. The receiver also includes terminals with electrical contacts that connect to the coil. Other receivers can have various other forms. For example, the armature can be an E-shaped spring or a T-shaped spring, as well as other spring structures; the coil does not need to be supported by a spool; the motor can be positioned in the front volume instead of the rear volume; the terminals can be positioned in other locations on the housing; and other variations.

[0024] exist Figure 2 In this receiver, a representative diaphragm 120 includes a generally planar blade 122 positioned within a frame 124, which is separated from the peripheral portion of the blade by a gap 126. In some diaphragms, one or more hinges connect the blade to the frame. Figure 2 In this embodiment, the hinge is a pair of cantilever hinges 127. In other implementations, the hinge is a torsion hinge. Alternatively, the hinge may comprise an adhesive, a membrane, or both. Figures 2 to 3 and Figures 4 to 6In this embodiment, the blade includes optional ribs 123 to increase the blade's stiffness. For the purposes of this disclosure, the blade including the ribs is a planar member.

[0025] exist Figures 1 to 3 and Figures 5 to 6 In this design, the blades, hinges, and frame constitute a non-assembled, integral component formed from sheet material during stamping and forming operations. Optional ribs can also be non-assembled integral parts of the blades and formed during these operations. Alternatively, the diaphragm can be an assembly of discrete components, wherein the blades are fastened to the frame by adhesives, welding, or other fastening mechanisms. The diaphragm can also be manufactured using additive manufacturing processes (e.g., 3D printing) and other known and future manufacturing operations.

[0026] The blades used in BA receivers configured for in-ear and over-ear applications can be formed from sheets with a thickness between 0.03 mm and 0.07 mm. Other portions of the diaphragm can also be made from the same sheet, as suggested. The thickness of other receiver blades can be outside this range. Additionally, the total thickness of the blades, including those shaped to form reinforcing ribs, can be greater than the thickness of the sheet. Among these and other blades, the blades have an effective modulus of not less than 30 GPa. The effective modulus of a sheet can be characterized by its flexural modulus (also known as bending modulus or flexural elastic modulus), which is a mechanical property that measures the stiffness or resistance to bending of a material. A sheet with an array of holes, cavities, or openings, made of the same alloy or composite material, has a lower effective modulus than a sheet without holes, cavities, or openings. Flexural modulus is expressed as the ratio of stress to strain, and the standard unit of measurement is Pascal (Pa or N / m). 2 ).

[0027] According to one aspect of this disclosure, a balanced armature receiver diaphragm includes a blade having a mass concentration region located between opposite ends of the blade and between opposite sides of the blade (e.g., in or near the center portion of the blade). The mass concentration region has an area density greater than the area density of the rest of the blade. For the purposes of this disclosure, "area density" refers to the mass of a portion of the blade (e.g., the mass concentration region) divided by the area of ​​that portion of the blade. In one implementation, the area density of the mass concentration region is at least twice the area density of the rest of the blade. In another implementation, the area density of the mass concentration region is at least three times the area density of the rest of the blade. In yet another implementation, the area density of the mass concentration region is at least six times the area density of the rest of the blade. In one implementation, the mass concentration region accounts for at least 10% of the total mass of the blade. In another implementation, the mass concentration region accounts for at least 25% of the total mass of the blade. In yet another implementation, the mass concentration region accounts for at least 40% of the total mass of the blade. In the diaphragm implementations described herein, the blade may not have a resonator. In other implementations, the diaphragm, and especially the blades, include a resonator combined with a mass-concentrated region.

[0028] The areal density of the mass concentration region can be increased by adding material to the mass concentration region, removing material from the portion of the blade excluding the mass concentration region, or by a combination thereof. Representative examples are further described in this paper.

[0029] In some implementations, discrete elements contribute to areas of mass concentration on the blade. Discrete elements can have various shapes, and representative examples are described herein. Discrete elements can be located on the top or bottom surface of the blade, or on both. Discrete elements can be held onto the blade by adhesives, epoxy bonding, riveting, crimping, or other fastening mechanisms. Figures 1 to 4 In this context, a tapered discrete element 160 is located on the top surface of the blade, in or near the middle or central portion of the blade, between the lateral sides and opposite ends of the blade. Figures 5 to 6 In the middle, discrete element 162 is located on the bottom surface of the blade.

[0030] Alternatively, the mass concentration region can be a region of the blade with increased thickness compared to other parts of the blade. The increased thickness can be material located on the top side, bottom side, or both of the top and bottom sides of the blade. Such a blade can be a non-assembled, monolithic component manufactured in processes such as casting, embossing, or additive manufacturing. In these implementations, the areal density of the mass concentration region can be attributed at least in part to additional material integrated into the blade.

[0031] In other implementations, the blade includes multiple mass reduction orifices in the portion of the blade excluding the mass concentration region. Mass reduction can be optimized by selecting the size and shape of the orifices and by appropriately distributing them around the blade. These orifices can be formed, in particular, in stamping, milling, casting, or additive manufacturing operations. In these implementations, the area density of the mass concentration region is at least partly due to the fact that there are fewer orifices per unit area in the mass concentration region (if any) compared to the number of orifices per unit area in other parts of the blade. In some implementations, there are no orifices in the mass concentration region. The mass of a blade with or without orifices can also be reduced by appropriately selecting the blade material and size.

[0032] In other implementations, in conjunction with the material added to the mass concentration region as described above, the blade may include an orifice. Figure 3 In this design, blade 172 includes a plurality of mass-reducing orifices 174 distributed around the blade and tapered, button-shaped discrete elements 160 located in or near the middle portion of the blade (e.g., on the top or bottom surface of the blade between opposite sides and opposite ends). Figure 5 and Figure 6 In the blade 182, there are multiple mass-reducing orifices 184 distributed around the blade and a blocky discrete element 162 located on the bottom surface of the blade near the middle portion of the blade.

[0033] Table I below contains a non-exhaustive list of representative materials from which blades, other parts of the diaphragm, and discrete or integrated elements contributing to the areal density of the mass concentration region can be manufactured. The values ​​in Table I are approximate and can vary depending on the exact material composition and geometry or shape. Materials with lower density or thinner thickness may also be used where a smaller reduction in the frequency of the desired frequency response peak is desired.

[0034] Table I

[0035]

[0036] In one implementation, the mass concentration region includes areas with a density greater than 2.7 g / cm³. 3 The material is [material name missing]. In other implementations, the mass concentration region includes regions with a density greater than 7.0 g / cm³. 3 Materials (e.g., stainless steel) or greater than 13.0 g / cm³ 3 Materials (e.g., tungsten carbide). In some implementations, the mass concentration region has a concentration exceeding 10 mg / cm³. 2 The areal density. For example, a 0.05 mm thick solid aluminum plate has an areal density of approximately 13.5 mg / cm³. 2In one implementation, the mass concentration region has a concentration greater than 50 mg / cm³. 2 The area density. In another implementation, the mass concentration region has a density greater than 100 mg / cm³. 2 The area density. In another implementation, the mass concentration region has a density greater than 200 mg / cm³. 2 The areal density. For example, a 0.05mm thick stainless steel plate fastened to a 0.05mm thick aluminum plate has an areal density of approximately 53mg / cm³. 2 The areal density of a 0.14mm thick stainless steel plate fastened to a 0.05mm thick aluminum plate is approximately 124mg / cm³. 2 The areal density of a 0.14mm thick tungsten carbide plate fastened to a 0.05mm thick aluminum plate is approximately 224mg / cm³. 2 The area density. The above representative examples are non-exhaustive and non-restrictive.

[0037] Increasing the total mass of the blades increases the total moving mass of the receiver during operation and can reduce the frequency of the first peak or other frequency response peaks below those primarily attributed to the diaphragm. Increasing the total mass of the blades can also reduce the response amplitude after the first peak. Therefore, it is generally preferred not to increase the total mass of the blades. By adding mass only to the mass concentration region, the total mass of the blades can be increased only slightly, remaining at approximately the same value, or even decreased, while still having the desired effect on the frequency response peaks primarily attributed to the diaphragm. The increase in mass in the mass concentration region can be offset by increasing the mass of the blades to reduce the orifice, by using a lower density material for the blades, or by using a thinner material, or by other methods of reducing the total mass of the blades. The total mass of the blades can even be reduced using these or other mass reduction methods.

[0038] Typically, the areal density of the mass concentration region and the total mass of the blade affect the frequency response of the balanced armature receiver. More specifically, the areal density of the mass concentration region primarily affects the frequency response peaks attributable to the diaphragm. Increasing the mass concentration region tends to decrease the frequency of the frequency response peaks primarily attributable to the diaphragm. Increasing the mass concentration region on the blade also tends to increase the amplitude of the peaks primarily attributable to the diaphragm. Conversely, decreasing the mass concentration region tends to increase the frequency of the frequency response peaks primarily attributable to the diaphragm. Decreasing the mass concentration region on the blade also tends to decrease the amplitude of the peaks primarily attributable to the diaphragm. Representative frequency response diagrams are described below.

[0039] Figure 7 The frequency response modeled for various diaphragm configurations implemented in a receiver connected to a 711-ear analog coupler is shown. Figure 7The third peak of each curve corresponds to the peak frequency response primarily attributable to the diaphragm. The “nominal” curve is the baseline curve for a diaphragm without a mass concentration region and without a resonator. The third peak of the “nominal” curve is 19 kHz. The “resonator” curve is used for diaphragms that include a resonator but not the mass concentration region. A resonator is an alternative or cumulative device that alters the receiver’s frequency response to a first order, which involves reducing the stiffness of the diaphragm. The third peak of the “resonator” curve is slightly greater than 17 kHz, almost 2 kHz lower than the third peak frequency of the “nominal” curve. The “small 0.3 mg mass” curve is used for blades with a mass of 0.3 mg that contributes to the areal density of the mass concentration region. The third peak of the “small 0.3 mg mass” curve is at approximately 16.5 kHz, almost 1 kHz lower than the third peak frequency of the “resonator” curve and approximately 2.5 kHz lower than the third peak frequency of the “nominal” curve. “Small 0.3 mg mass” represents a frequency reduction of more than 10% relative to the “nominal” curve. The "large 0.6 mg mass" curve is used for blades with a mass of 0.6 mg that contributes to the areal density of the mass concentration region. The third peak of the "large 0.6 mg mass" curve is slightly greater than 15 kHz, almost 4 kHz lower than the third peak frequency of the "nominal" curve, almost 2 kHz lower than the third peak frequency of the "resonator" curve, and more than 1 kHz lower than the third peak frequency of the "small 0.3 mg mass" curve. Compared to the "nominal" curve, "large 0.6 mg mass" indicates a frequency reduction of more than 15%. Figure 7 All other properties and characteristics (e.g., size, shape, material, etc.) of the diaphragm modeled by the curves in the graph are the same. Figure 7 The increase in the amplitude of the third peak of the frequency response relative to the "nominal" and "resonator" curves is also shown. The third peak of the "large 0.6 mg mass" curve has a higher amplitude than that of the "small 0.3 mg mass" curve.

[0040] exist Figure 8 In this configuration, blade 802 pivots about hinge end 804 when driven by a movable portion of armature 806, which is connected to blade via a drive rod or other connecting rod 808. The frequency response peak of the diaphragm is primarily attributed to... Figure 9 The first bending mode of the blade 802 shown is generated. Adding mass to the blade 802 tends to lower the resonant frequency of the first bending mode of the blade (referred to herein as the "bending mode frequency"). By positioning the mass concentration region at or near the center of the blade, the total mass increase of the blade can be relatively small, while having a similar effect to adding a large, uniformly distributed mass. The mass concentration region lowers the resonant frequency of the first bending mode of the blade. The reduction in the resonant frequency of the first bending mode can be mainly attributed to shifting the peak frequency response of the diaphragm to a lower frequency and increasing the amplitude of the peak, as well as other beneficial acoustic effects described herein.

[0041] While this disclosure and what is now considered the best mode thereof have been described in a manner that establishes ownership and enables those skilled in the art to make and use the invention, it should be understood and recognized that many equivalents exist of the representative embodiments described herein, and that various modifications and variations may be made to the representative embodiments without departing from the scope and spirit of the invention, which is not limited to the described embodiments but is defined by the appended claims and their equivalents.

Claims

1. A balanced armature receiver diaphragm, the balanced armature receiver diaphragm comprising: The blade includes a planar member having a material thickness between 0.03 mm and 0.07 mm and an effective modulus of not less than 30 gigapascals. The blade has a mass concentration region located at or near the center of the blade. The mass concentration region has an area density greater than that of other parts of the blade. The mass concentration region is configured to reduce the bending mode frequency of the blade compared to the bending mode frequency of the blade without the mass concentration region.

2. The balanced armature receiver diaphragm according to claim 1, wherein the balanced armature receiver diaphragm further comprises discrete elements fastened to the blades, wherein, The discrete components contribute to the mass concentration area.

3. The balanced armature receiver diaphragm according to claim 2, wherein, The area density of the mass concentration region is at least twice the area density of the other parts of the blade.

4. The balanced armature receiver diaphragm according to claim 2, wherein, The area density of the mass concentration region is at least three times the area density of the other parts of the blade.

5. The balanced armature receiver diaphragm according to claim 2, wherein, The area density of the mass concentration region is at least six times the area density of the other parts of the blade.

6. The balanced armature receiver diaphragm according to claim 2, wherein, The mass concentration region has a concentration of at least 50 mg / cm³. 2 The area density.

7. The balanced armature receiver diaphragm according to claim 2, wherein, The mass concentration region includes materials with a density greater than 2.7 g / cm³.

8. The balanced armature receiver diaphragm according to claim 7, wherein, The mass concentration area includes a mass of at least 0.3 mg.

9. The balanced armature receiver diaphragm according to claim 7, wherein, The mass concentration region includes a mass of at least 0.6 mg.

10. The balanced armature receiver diaphragm according to claim 1, further comprising a plurality of mass reduction orifices passing through the blade, wherein, The area density of the mass concentration region is at least partly attributed to the fact that there are fewer orifices per unit area in the mass concentration region compared to the orifices per unit area in the other parts of the blade.

11. The balanced armature receiver diaphragm according to claim 1, wherein, The blade has no resonator.

12. The balanced armature receiver diaphragm according to claim 1, wherein, The mass concentration region includes at least 10% of the total mass of the blade.

13. A balanced armature receiver, the balanced armature receiver comprising: A housing having a sound port; A diaphragm is disposed in the housing and divides the housing into a rear volume and a front volume, the front volume being acoustically coupled to the outside of the housing through the sound port. The diaphragm includes blades having a mass concentration region located at or near the center of the blade, the mass concentration region having an area density greater than that of the other parts of the blade. An electric motor, disposed within the housing, includes a coil magnetically coupled to an armature having end portions movably arranged between a plurality of magnets held by a yoke. This armature is coupled to the blade, wherein the armature moves the blade in response to an excitation signal applied to the coil. The mass concentration region is attributed to the shift of the diaphragm's frequency response peak to a frequency lower than the frequency response peak in the absence of a mass concentration region.

14. The balancing armature receiver of claim 13, further comprising a discrete element fastened to the blade, wherein, The discrete components contribute to the mass concentration area.

15. The balanced armature receiver according to claim 14, wherein, The blade includes a planar member having a material thickness between 0.03 mm and 0.07 mm and an effective modulus of not less than 30 gigapascals.

16. The armature receiver of claim 14, further comprising: A frame arranged around the periphery of the blade, the frame being separated from the blade by gaps; as well as A membrane covering all mass reduction pores and gaps in the blade, wherein the membrane allows the blade to move relative to the frame.

17. The balanced armature receiver according to claim 14, wherein, The mass concentration region increases the sound pressure level attributable to the frequency response peak of the diaphragm of the balanced armature receiver, compared to the sound pressure level attributable to the frequency response peak of the diaphragm of the balanced armature receiver in the absence of the mass concentration region.

18. The balanced armature receiver according to claim 14, wherein, The mass concentration region causes a shift of at least 10% in the peak frequency response of the diaphragm attributable to the balanced armature receiver.

19. The balanced armature receiver according to claim 14, wherein, The mass concentration region causes a shift of at least 15% in the peak frequency response of the diaphragm attributable to the balanced armature receiver.

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