Micro speaker with symmetrical voice coil and magnetic circuit

Abstract

An ultra-thin micro speaker is provided with an intermediate gasket between a voice coil and a diaphragm, so that the distance between the top of a top plate and the top of the voice coil can be equal to the distance between the bottom of the top plate and the bottom of the voice coil, and the winding height has a symmetrical relationship in the magnetic circuit, and its BL(x) curve has better symmetry.

Description

Technical Field

[0001] The present disclosure generally relates to a speaker, and more particularly to an ultra-thin micro speaker having a thin structure and a symmetrical voice coil and magnetic circuit. Background Art

[0002] Today, electronic products are increasingly integrated and thinner. The market is also placing increasing demands on micro speakers. Micro speakers require specific performance, including thinness, high sensitivity, better bass, and lower distortion at low frequencies.

[0003] Speakers convert electrical energy into sound. Existing ultrathin microspeaker structures typically include a diaphragm, a magnetic circuit with a magnetic gap, and a voice coil. The magnetic circuit structure can concentrate the magnetic flux generated by the magnet into the magnetic gap. When electrical energy flows into the voice coil, it generates an induced magnetic field that interacts with the magnetic flux in the magnetic gap. The voice coil can carry a current in a direction substantially perpendicular to the direction of the magnetic flux generated by the magnet. The interaction between the voice coil current and the magnetic flux causes the voice coil to oscillate linearly within the length of the magnetic gap, which moves the diaphragm to produce audible sound.

[0004] However, the limited internal space in existing ultra-thin microspeakers can easily lead to mechanical defects such as soft and hard bottoming when the speaker is operated at high power. In these cases, contact between the diaphragm or voice coil and the magnetic circuit structure may occur, causing noise in the speaker system. Furthermore, the asymmetrical winding heights in the magnetic circuit result in different force factors (BL) due to the different upper and lower winding heights of the voice coil in the magnetic circuit structure. This increases the speaker's harmonic distortion, leading to an increase in total harmonic distortion.

[0005] As in the above scheme, existing ultra-thin micro speakers cannot ensure the structural symmetry of the voice coil and magnetic circuit due to structural limitations. As the voice coil vibrates up and down in the magnetic circuit, the force transmission from the voice coil to the diaphragm is unbalanced, making it difficult to meet the requirements of low-distortion sound production in speakers. Therefore, it is necessary to design an ultra-thin micro speaker with a symmetrical voice coil and magnetic circuit, while maintaining the soft bottoming space and hard bottoming space. Summary of the Invention

[0006] The present invention aims to provide a technical solution for an ultra-thin micro-speaker that requires a thin structure, meets the design requirements of magnetic circuit symmetry in acoustic theory, and addresses existing structural design issues. Specifically, while maintaining a thin structure, the voice coil and magnetic circuit are designed to be symmetrical. This symmetric structure achieves low distortion when applying large-amplitude output and improves the sound reproduction quality of the ultra-thin micro-speaker, resulting in a more realistic sound experience for users.

[0007] One embodiment of the present disclosure provides an ultrathin micro-speaker structure, comprising a diaphragm, a magnetic circuit structure, and a voice coil. The magnetic circuit structure may include a yoke, side top plates, side magnets, a top plate, and a magnet. The magnetic circuit structure may concentrate the magnetic flux generated by the magnet into the magnetic gap between the top plate and the side top plates. When current flows through the voice coil, the voice coil may cause linear oscillation, forcing the diaphragm and the voice coil to move together to produce audible sound.

[0008] Another embodiment of the present disclosure provides a solution for optimizing the structural design to improve the performance of an ultra-thin microspeaker by placing an intermediate washer between the voice coil and the diaphragm, while maintaining the soft bottoming space and maintaining the speaker's rated power. The addition of the intermediate washer allows the voice coil to be positioned symmetrically in the magnetic circuit about the central horizontal plane of the top plate. This allows the distance between the top of the top plate and the top of the voice coil to be equal to the distance between the bottom of the top plate and the bottom of the voice coil. This creates a symmetrical relationship between the winding height in the magnetic circuit and reflects a more symmetrical BL(x) curve. In this case, the nonlinear parameter BL(x) curve becomes relatively symmetrical as the voice coil moves up and down, resulting in low total harmonic distortion (THD) in the speaker. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present disclosure may be better understood by reading the following description of non-limiting embodiments with reference to the accompanying drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed on illustrating the principles of the present invention. Furthermore, in the drawings, like reference numerals designate corresponding parts throughout the different views, in which:

[0010] Figure 1A and Figure 1B is a schematic diagram showing the structure of an ultrathin microspeaker according to an embodiment of the present invention.

[0011] Figure 1C It shows Figure 1B A close-up view of portion E of the ultra-thin microspeaker.

[0012] Figure 2A is a schematic diagram showing the structure of an ultrathin microspeaker according to another embodiment of the present invention.

[0013] Figure 2B It shows Figure 2A A close-up view of portion D of the ultra-thin microspeaker.

[0014] Figure 3 It shows that Figures 2A to 2B FIG. 1 is an exploded view showing an example of the structure of an ultrathin microspeaker according to an embodiment of the present invention.

[0015] Figure 4 It shows Figures 1A to 1C Ultra-thin micro speakers and Figures 2A to 2B A graph comparing the BL(x) curves of the ultra-thin micro speakers in FIG. DETAILED DESCRIPTION

[0016] As required, detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The drawings are not necessarily to scale; some features may be exaggerated or minimized to illustrate component details. Therefore, the specific structural and functional details disclosed herein should not be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0017] In an embodiment of the present disclosure, Figures 1A to 1C FIG shows the structure of an ultra-thin micro speaker 100, which includes a diaphragm 101, a magnetic circuit structure, and a voice coil 106. The magnetic circuit structure may include a yoke 105, a side top plate 103, a side magnet 104, a top plate 107, and a magnet 108. Figure 1A As shown, the side magnets 104 and the magnets 108 are respectively placed at the same level on the yoke 105 and spaced apart to form a magnetic gap between them. The top plate 107 is arranged on top of the magnet 108, and the side top plates 103 are respectively arranged on top of the side magnets 104 at the same level as the top plate 107. There is also a magnetic gap between the top plate 107 and the side top plates 103. The voice coil 106 is connected to the diaphragm 101 and suspended in the magnetic gap. Therefore, a bonding surface is formed between the voice coil 106 and the diaphragm 101. The ultra-thin micro speaker may also include a frame 102, which is used to fix the magnetic circuit therein. The frame 102 is connected to the diaphragm 101 via a free edge (such as a flexible folding ring). The magnetic circuit structure can concentrate the magnetic flux generated by the magnet into the magnetic gap. When electrical energy flows into the voice coil 106, an induced magnetic field that interacts with the magnetic flux in the magnetic gap can be generated. The voice coil 106 can carry a current in a direction substantially perpendicular to the direction of the magnetic flux generated by the magnets 104, 108, so that the interaction between the voice coil current and the magnetic flux can cause the voice coil 106 to oscillate linearly within the length of the magnetic gap, which moves the diaphragm 101 to produce audible sound.

[0018] Because Figure 1A The internal space of the ultra-thin micro speaker shown is always limited, especially the soft bottoming space 110 and the hard bottoming space 111 are limited, and thus it is easy to cause mechanical defects such as soft bottoming and hard bottoming when the speaker is operated at high power. In this case, contact may occur between the diaphragm 101 or the voice coil 106 and the magnetic circuit structure, and generate noise in the speaker system. In addition, referring to Figure 1B and Figure 1C Since the voice coil 106 used in the ultra-thin micro speaker generally has no skeleton, in order to reserve enough travel space for the voice coil to move up and down, the distance between the top of the top plate 107 and the top of the voice coil 106 is ( Figure 1C The distance B) is generally longer than the distance between the bottom of the top plate 107 and the bottom of the voice coil 106 ( Figure 1C Distance A in FIG. Distance A is not equal to distance B based on the top and bottom of top plate 107. In this case, the winding heights have an asymmetrical relationship in the magnetic circuit, resulting in different force factors (BL) caused by the different upper and lower winding heights of voice coil 107 in the magnetic circuit structure. This increases the harmonic distortion of the speaker, leading to an increase in total harmonic distortion.

[0019] In another embodiment of the present disclosure, Figures 2A to 2B The improved ultra-thin microspeaker 200 is shown with an additional intermediate gasket 209 arranged and sandwiched at the bonding surface between the diaphragm 201 and the voice coil 206 and connected to both.

[0020] like Figure 2A As shown, it generally has the same Figure 1A The ultra-thin micro-speaker 200 of the structure shown in the figure includes a diaphragm 201, a magnetic circuit structure, and a voice coil 206. The magnetic circuit structure may include a yoke 205, a side top plate 203, a side magnet 204, a top plate 207, and a magnet 208. The magnetic circuit structure can concentrate the magnetic flux generated by the magnet into the magnetic gap formed between the top plate 207 and the side top plate 203. The intermediate washer 209 is sandwiched and connected between the voice coil 206 and the diaphragm 201, and the intermediate washer 209 is suspended in the magnetic gap, as shown in FIG. Figure 2A In addition, the ultra-thin micro speaker may further include a frame 202, which is used to fix the magnetic circuit structure therein. Figure 2A As shown, the frame 202 is connected to the diaphragm 201 via a free edge (such as a flexible folded ring). When electrical energy flows into the voice coil 206, an induced magnetic field is generated that interacts with the magnetic flux in the magnetic gap. The voice coil 206 carries a current in a direction substantially perpendicular to the direction of the magnetic flux generated by the magnets 204 and 208, so that the interaction between the voice coil current and the magnetic flux can cause the voice coil 206 to oscillate linearly within the length of the magnetic gap, which causes the diaphragm 201 to move to produce audible sound.

[0021] Still refer to Figure 2A In the structure of the ultra-thin micro speaker 200 provided in the present disclosure, an intermediate gasket 209 is added so that the voice coil 206 can be configured to be aligned with the central horizontal plane ( Figure 2B In this case, by adding an intermediate gasket instead of a segment of the voice coil, based on the top and bottom of the top plate 207, the Figure 2B In the vertical direction shown, the distance A between the bottom of the top plate 207 and the bottom of the voice coil 206 is equal to the distance B between the top of the top plate 207 and the top of the voice coil 206, and the soft bottoming structure and the hard bottoming structure will not be affected, that is, the intermediate gasket 209 is added to allow the voice coil 206 and the magnetic circuit structure to be designed in a symmetrical manner, and at the same time, the soft bottoming space and the hard bottoming space remain unchanged, and the rated power of the speaker can be maintained.

[0022] Now refer to Figure 3 , by way of example, in Figure 3 1 shows an exploded view of an ultra-thin micro speaker as provided in the present disclosure in assembly order, which in turn includes a diaphragm 201, an intermediate gasket 209, a voice coil 206, a side top plate 203, a frame 202, a top plate 207, a magnet 208, and a side magnet 204. By way of example, Figure 3 The product of the ultra-thin micro speaker shown is rectangular in shape, and accordingly, all components used in the speaker are arranged or shaped according to its rectangular shape. Therefore, the intermediate gasket 209 is configured as a rectangular ring. However, according to various actual usage scenarios, the intermediate gasket 209 may alternatively be shaped into various shapes, such as but not limited to square, circular, racetrack, etc. In an embodiment, the intermediate gasket 209 may also be configured to be individually divided into multiple sections using one or more grooves. The intermediate gasket 209 may be made of various materials, including but not limited to metal, plastic, paper or other high temperature resistant or lightweight materials, which may result in further reducing the overall weight of the speaker. In addition, as Figure 3 The magnetic circuit structure of the ultra-thin micro speaker 200 shown includes a magnet 8 and two side magnets 204. However, the magnetic circuit may include a magnetic circuit formed with a single magnet structure. Alternatively, the magnetic circuit may have a multi-magnet structure, such as three magnets, five magnets, etc.

[0023] Figure 4 Shown Figures 1A to 1C Ultra-thin micro speakers and Figures 2A to 2B A graph comparing the BL(x) curves of the ultra-thin micro speakers of FIG. In the graph of the BL(x) curve, the ordinate represents the value of BL(x), and the abscissa represents the displacement of the voice coil relative to the magnetic circuit structure. The symmetry of the BL(x) curve may be affected only by the displacement of the voice coil relative to the top plate or the side top plate. Figure 4 In the figure, the BL(x) curve drawn with a dotted line reflects the following Figures 1A to 1C The asymmetry of the voice coil and magnetic circuit in the loudspeaker shown. The BL(x) curve with a dashed line is about the central longitudinal axis (at Figure 4 , x=0) is asymmetric, which indicates that Figures 1A to 1C The asymmetry of the BL(x) curve will result in an unbalanced force factor between the magnetic circuit structure and the voice coil when the ultra-thin microspeaker is operating at large displacement vibration. In contrast, the BL(x) curve drawn with a solid line shows much better symmetry about the central longitudinal axis (X=0), which reflects the following: Figure 2A and Figure 2B The speaker provided in this disclosure features a symmetrical voice coil and magnetic circuit. In this case, the BL(x) curve exhibits enhanced symmetry, meaning the winding heights have a symmetrical relationship within the magnetic circuit, with the upper and lower winding heights experiencing the same magnetic flux density. This design, while maintaining a thin structure, achieves a symmetrical voice coil and magnetic circuit. This reduces distortion even when applying high-amplitude output, improving the sound reproduction quality of the ultra-thin micro-speaker and providing users with a more realistic sound experience.

[0024] The aforementioned technical solutions provided in this disclosure enable the microspeaker to obtain a relatively symmetrical BL(x) curve while maintaining an ultra-thin structure, thereby minimizing low-frequency distortion, specifically in the following aspects:

[0025] When assembling the vibration system, add an intermediate washer between the voice coil and the diaphragm;

[0026] ●In the design of the voice coil, the winding height and magnetic circuit structure can be matched to design a symmetrical structure.

[0027] The present disclosure provides a technical solution for an ultra-thin micro-speaker with a thin structure that meets the design requirements of magnetic circuit symmetry in acoustic theory. The ultra-thin micro-speaker features a symmetrical voice coil and magnetic circuit structure, improving sound reproduction quality and enabling users to experience more realistic sound when using the speaker. Therefore, the ultra-thin micro-speaker disclosed herein can be widely used in a variety of fields and offer improved performance. For example, it can be used in any integrated and thinned electronic product, such as, but not limited to, mobile phones, tablets, computers, or audio playback devices.

[0028] Although exemplary embodiments have been described above, these embodiments are not intended to describe all possible forms of the present invention. Rather, the words used in this specification are descriptive rather than restrictive, and it should be understood that various changes may be made without departing from the spirit and scope of the present invention. In addition, the features of the various embodiments of implementation may be combined to form additional embodiments of the present invention.

Claims

1. A loudspeaker, comprising: diaphragm; a magnetic circuit structure, the magnetic circuit structure including a magnetic gap, the magnetic circuit also including a top plate; a voice coil suspended in the magnetic gap, an intermediate gasket, the intermediate gasket being sandwiched between the diaphragm and the voice coil and connecting the two, wherein in the vertical direction, the distance between the top of the voice coil and the top of the top plate is equal to the distance between the bottom of the voice coil and the bottom of the top plate, and The intermediate gasket is arranged so that the voice coil and the magnetic circuit structure are symmetrical about a central horizontal plane of the top plate. 2 . The speaker according to claim 1 , wherein the magnetic circuit structure further includes at least a side top plate, and the magnetic gap is formed between the top plate and the side top plate. 3 . The loudspeaker according to claim 2 , wherein the voice coil is arranged symmetrically with respect to the magnetic circuit structure about a central horizontal plane of the top plate and the side top plates. The loudspeaker of claim 1 , wherein the intermediate gasket is configured as a ring. 5 . The speaker of claim 4 , wherein the intermediate gasket is formed in a rectangular, circular or racetrack shape. The loudspeaker according to claim 1 , wherein the magnetic circuit structure further comprises a magnet structure formed with a single magnet.

7. The loudspeaker according to claim 1, wherein the magnetic circuit structure is formed with a multi-magnet of three magnets or five magnets.

8. The loudspeaker of claim 1, wherein the intermediate gasket is made of a lightweight material.

9. The loudspeaker of claim 8, wherein the intermediate gasket is made of at least one of metal, plastic, and paper.

10. The speaker of claim 1, wherein the speaker is an ultra-thin micro speaker.

11. The speaker of claim 1, wherein the speaker is used for integration into thinned electronic products.

12. The speaker of claim 11, wherein the electronic product is a mobile phone or a tablet computer.

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