A planar loudspeaker and a headphone

Abstract

The present invention provides a planar loudspeaker and an earphone, which includes a diaphragm whose periphery is fixed on a frame, and a permanent magnet array composed of a plurality of permanent magnets. The permanent magnet array is arranged at an interval from the diaphragm and is correspondingly arranged with the coils coated or embedded on the diaphragm. The permanent magnet has a first end facing the diaphragm and a second end facing away from the diaphragm. A magnetic conductor is arranged near at least the permanent magnet in the middle position of the permanent magnet array, and the second ends of two adjacent permanent magnets with opposite magnetic poles can be selectively connected to both ends of the magnetic conductor respectively. It can facilitate users to flexibly adjust the differences in the vibration directions and amplitudes of various parts of the diaphragm, reduce distortion, and improve sound quality and sound power.

Description

Technical Field

[0001] The present invention relates to the field of audio output devices, and particularly to a planar loudspeaker and an earphone. Background Art

[0002] The planar loudspeaker embeds a planar voice coil into a thin and light diaphragm. Like a printed circuit board, it can make the driving force evenly distributed. The magnets are concentrated on one or both sides of the diaphragm, and the diaphragm vibrates in the magnetic field formed by them. The diaphragm of the flat earphone equipped with a planar loudspeaker is not as light as that of an electrostatic earphone, but has the same large vibration area and similar sound quality.

[0003] The planar loudspeaker combines the advantages of both moving coil loudspeakers and electrostatic loudspeakers. It has better performance in the low frequency compared with electrostatic ones, and is also stronger than moving coil ones in the high frequency. The structure of its core transducer is usually that a plurality of strip-shaped permanent magnets are arranged in parallel on a yoke, and a diaphragm is arranged parallel to the pole faces of these permanent magnets. The periphery of the diaphragm is fixed on a frame and is in a tensioned state, and a coil is arranged at a position on the diaphragm opposite to the permanent magnet. The current flowing inside the coil is orthogonal to the magnetic field generated by the permanent magnet. Thus, by passing an alternating current through the coil, the coil generates a force that complies with Faraday's law. Under the action of this force, the diaphragm vibrates in the vertical direction, and the alternating current signal is converted into a sound signal.

[0004] The maximum amplitude of the existing planar loudspeaker diaphragm is limited by the distance between the diaphragm and the permanent magnet. In order to ensure the magnetic field strength at the diaphragm, the distance between the diaphragm and the permanent magnet is very small. Therefore, the vibration amplitude of the diaphragm is limited, and there are low power and distortion phenomena. Summary of the Invention

[0005] In view of the above-mentioned drawbacks in the prior art, the present invention provides a planar loudspeaker, including a diaphragm with its periphery fixed on a frame, and a permanent magnet array composed of a plurality of permanent magnets. The permanent magnet array is arranged at an interval with the diaphragm and is correspondingly arranged with the coil coated or embedded on the diaphragm. The permanent magnet has a first end facing the diaphragm and a second end facing away from the diaphragm. A magnetic conductor is arranged near at least the permanent magnet at the middle position of the permanent magnet array, and the second ends of two adjacent permanent magnets with opposite magnetic poles can be selectively connected to both ends of the magnetic conductor respectively.

[0006] Preferably, the permanent magnets forming the permanent magnet array are evenly distributed.

[0007] Preferably, the permanent magnet array is composed of a plurality of concentrically nested permanent magnets; or, the permanent magnet array is composed of a plurality of parallel strip-shaped permanent magnets.

[0008] Preferably, the permanent magnet array has two layers, and the diaphragm is located between the two layers of the permanent magnet array.

[0009] Preferably, the magnetic field intensity generated by the permanent magnet located at the middle position of the permanent magnet array is not less than the magnetic field intensity generated by the permanent magnet located at the peripheral position of the permanent magnet array.

[0010] Preferably, the thickness of the permanent magnet located at the middle position of the permanent magnet array is less than the thickness of the permanent magnet located at the peripheral position of the permanent magnet array.

[0011] Preferably, the second end of the permanent magnet is a plane parallel to the diaphragm, and the distance between the first end of the permanent magnet located at the middle position of the permanent magnet array and the diaphragm is greater than the distance between the first end of the permanent magnet located at the peripheral position of the permanent magnet array and the diaphragm.

[0012] Preferably, a magnetic conductor is provided near all the permanent magnets.

[0013] Preferably, a sound guiding hole perpendicular to the diaphragm is provided at a position on the magnetic conductor between two permanent magnets.

[0014] Preferably, it further includes a plurality of magnetic conductor actuating members. Each magnetic conductor actuating member drives one or a group of the magnetic conductors to move towards or away from the second end of the permanent magnet, so that the magnetic conductor is connected to or disengaged from the second end of the permanent magnet; by controlling different magnetic conductor actuating members, the distances between the second ends of the permanent magnets at different positions and the corresponding magnetic conductors are different, and thus the magnetic field intensities generated by the permanent magnets at different positions in the permanent magnet array are different.

[0015] Preferably, the frame is provided with a guiding hole perpendicular to the diaphragm. The magnetic conductor actuating member is a guiding block capable of axially moving along the guiding hole, and the guiding block is fixedly connected to the magnetic conductor along the axial direction of the guiding hole.

[0016] Preferably, the guiding hole is in threaded cooperation with the guiding block, and the relative rotational movement of the guiding block with respect to the guiding hole can cause the guiding block to axially move with respect to the guiding hole.

[0017] Preferably, the second end of the permanent magnet and one end of the magnetic conductor facing the second end have a mutually matching clamping structure. When the magnetic conductor is connected to the second end, the clamping structure keeps the permanent magnet and the magnetic conductor in a connected state.

[0018] Preferably, at least the permanent magnet located at the middle position of the permanent magnet array is a neodymium iron boron magnet.

[0019] The present invention also provides an earphone having the planar speaker of any one of the above.

[0020] A planar speaker and an earphone provided by the present invention include a diaphragm whose periphery is fixed to a frame, and a permanent magnet array composed of a plurality of permanent magnets. The permanent magnet array is arranged at an interval from the diaphragm and corresponds to a coil coated or embedded on the diaphragm; the permanent magnet has a first end facing the diaphragm and a second end facing away from the diaphragm; a magnetic conductor is arranged near at least the permanent magnet at the middle position of the permanent magnet array, and the second ends of two adjacent permanent magnets with opposite magnetic poles can be selectively connected to both ends of the magnetic conductor respectively; it can facilitate the user to flexibly adjust the differences in the vibration directions and amplitudes of various parts of the diaphragm, reduce distortion, and improve sound quality and sound power. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the first planar speaker according to an embodiment of the present invention;

[0022] Figure 2 Schematic diagram of the second planar speaker according to an embodiment of the present invention;

[0023] Figure 3 Schematic diagram of the third planar speaker according to an embodiment of the present invention;

[0024] Figure 4 For the present invention Figure 3 Schematic diagram of the state change of the planar speaker shown;

[0025] Figure 5 Schematic diagram of the fourth planar speaker according to an embodiment of the present invention;

[0026] Figure 6 For the present invention Figure 1 、 2 Schematic diagram of the change of the vibration characteristic curve that can be achieved by the planar speakers in Embodiments 1, 3, and 5 of the present invention.

[0027] Among them, planar speaker - 100, permanent magnet - 110, permanent magnet at the peripheral position - 110A, permanent magnet at the middle position - 110B, diaphragm - 120, coil - 130, magnetic conductor - 140, frame - 150, guide hole - 151, guide block 160. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] In order to address the problems that the overall amplitude of the diaphragm of the existing planar speaker is limited and there is distortion, the planar speaker and earphone provided by the present invention are realized through the following technical solutions:

[0029] Embodiment 1:

[0030] This embodiment provides a planar loudspeaker 100. Please refer to Figures 1 to 6 , which includes a diaphragm 120 with its periphery fixed on a frame 150, a permanent magnet array composed of a number of permanent magnets 110. The permanent magnet array is arranged at an interval from the diaphragm 120 and is correspondingly arranged with a coil 130 coated or embedded on the diaphragm 120; the permanent magnet 110 has a first end facing the diaphragm 120 and a second end facing away from the diaphragm 120; a magnetic conductor 140 is arranged near at least the permanent magnet 110B in the middle position of the permanent magnet array. The second ends of two adjacent permanent magnets 110 with opposite magnetic poles can be selectively connected to both ends of the magnetic conductor 140 respectively. The magnetic conductor 140 can effectively reduce the magnetic field interference generated by one pole with opposite opposed magnetic poles of the permanent magnet 110 on the magnetic field located between the two permanent magnets 110, thereby reducing the field strength loss. For example, only the permanent magnet 110B in the middle position of the permanent magnet array has its magnetic field strength enhanced through the magnetic conductor 140, while the permanent magnet 110A in the peripheral position of the permanent magnet array is not equipped with the magnetic conductor 140, so that the magnetic field strength generated by the permanent magnet 110B in the middle position of the permanent magnet array is greater than the magnetic field strength generated by the permanent magnet 110A in the peripheral position of the permanent magnet array.

[0031] Specifically, the permanent magnets 110 constituting the permanent magnet array are evenly distributed.

[0032] Specifically, the permanent magnet array is composed of a number of concentrically nested permanent magnets 110; or, the permanent magnet array is composed of a number of strip-shaped permanent magnets 110 arranged in parallel.

[0033] Specifically, the permanent magnet array has two layers, and the diaphragm 120 is located between the two layers of the permanent magnet array.

[0034] Specifically, the magnetic field strength generated by the permanent magnet 110B in the middle position of the permanent magnet array is not less than the magnetic field strength generated by the permanent magnet 110A in the peripheral position of the permanent magnet array. When the magnetic field strength generated by the permanent magnet 110B in the middle position of the permanent magnet array is 3.5 - 5.0 times that generated by the permanent magnet 110A in the peripheral position of the permanent magnet array, the vibration in the middle position of the diaphragm 120 can be made more sufficient, and the middle and high frequency distortion of the diaphragm 120 can be reduced to the greatest extent. This can be achieved by making the maximum magnetic energy product of the permanent magnet 110B in the middle position of the permanent magnet array greater than the maximum magnetic energy product of the permanent magnet 110A in the peripheral position of the permanent magnet array.

[0035] Specifically, please refer to Figure 2, the thickness of the permanent magnet 110B located at the middle position of the permanent magnet array is less than the thickness of the permanent magnet 110A located at the peripheral position of the permanent magnet array.

[0036] Specifically, the second end of the permanent magnet 110 is parallel to the plane of the diaphragm 120, and the distance between the first end of the permanent magnet 110B located at the middle position of the permanent magnet array and the diaphragm 120 is greater than the distance between the first end of the permanent magnet 110A located at the peripheral position of the permanent magnet array and the diaphragm 120. Based on this, the vibration space in the middle position of the diaphragm 120 can be made larger, effectively reducing the mid - high frequency distortion of the planar loudspeaker.

[0037] Specifically, please refer to Figure 3 , Figure 4 , a magnetic conductor 140 is provided near all the permanent magnets 110.

[0038] Specifically, a sound guiding hole perpendicular to the diaphragm 120 is provided at the position of the magnetic conductor 140 between two permanent magnets 110.

[0039] Specifically, it further includes a plurality of magnetic conductor 140 actuators, and each magnetic conductor 140 actuator drives one or a group of the magnetic conductors 140 to move towards or away from the second end of the permanent magnet 110, so that the magnetic conductor 140 connects or disconnects from the second end of the permanent magnet 110; by controlling different magnetic conductor 140 actuators, the distances between the second ends of the permanent magnets 110 at different positions and the corresponding magnetic conductors 140 are different, and thus the magnetic field intensities generated by the permanent magnets 110 at different positions in the permanent magnet array are different. The user can flexibly change the overall acoustic characteristics of the planar loudspeaker 100 by adjusting the distance.

[0040] Specifically, the magnetic field intensities generated by the permanent magnets 110 at different positions in the permanent magnet array are different, so that at least one acoustic characteristic of the entire loudspeaker is optimized. The acoustic characteristics include the following characteristic information: the high - frequency frequency response curve of the diaphragm 120; the mid - frequency frequency response curve of the diaphragm 120; the low - frequency frequency response curve of the diaphragm 120; one or more mel - cepstral coefficients of the diaphragm 120; the frequency response at one or more predetermined frequencies of the diaphragm 120; the frequency response at one or more predetermined positions of the diaphragm 120; the frequency response of the diaphragm 120 across one or more predetermined frequency ranges; one or more resonance frequency responses that may exist in the acoustic path of the diaphragm 120. For example, please refer to Figure 6, the magnetic field intensities generated by the permanent magnets 110 at different positions within the permanent magnet array are different, enabling the amplitude characteristics of the diaphragm 120 to change between the solid line and the dashed line; among them, the amplitude characteristics shown by the dashed line are more suitable for expressing medium and high-frequency audio.

[0041] Specifically, please refer to Figure 5 , the frame 150 is provided with a guide hole 151 perpendicular to the diaphragm 120, and the actuator of the magnetic conductor 140 is a guide block 160 capable of moving axially along the guide hole 151, and the guide block 160 is fixedly connected to the magnetic conductor 140 along the axial direction of the guide hole 151.

[0042] Specifically, the guide hole 151 is in threaded cooperation with the guide block 160, and the rotational movement of the guide block 160 relative to the guide hole 151 can cause the guide block 160 to generate axial movement relative to the guide hole 151.

[0043] Specifically, the second end of the permanent magnet 110 and one end of the magnetic conductor 140 facing the second end are provided with a snap-fit structure that cooperates with each other. When the magnetic conductor 140 is connected to the second end, the snap-fit structure keeps the permanent magnet 110 and the magnetic conductor 140 in a connected state.

[0044] Specifically, at least the permanent magnet 110 located at the middle position of the permanent magnet array is a neodymium iron boron magnet.

[0045] A planar loudspeaker proposed in this embodiment includes a diaphragm 120 whose periphery is fixed on a frame 150, a permanent magnet array composed of a plurality of permanent magnets 110, the permanent magnet array is arranged at an interval from the diaphragm 120 and is correspondingly arranged with a coil 130 coated or embedded on the diaphragm 120; the permanent magnet 110 has a first end facing the diaphragm 120 and a second end facing away from the diaphragm 120; a magnetic conductor 140 is arranged near at least the permanent magnet 110B at the middle position of the permanent magnet array, and the second ends of two adjacent permanent magnets 110 with opposite magnetic poles can be selectively connected to both ends of the magnetic conductor 140 respectively; it can conveniently enable the user to flexibly adjust the differences in the vibration directions and amplitudes of various parts of the diaphragm 120, reduce distortion, and improve sound quality and sound power.

[0046] Embodiment 2:

[0047] This embodiment proposes a headphone, which has the planar loudspeaker 100 of any one of Embodiment 1 and has the same performance, which will not be elaborated here.

[0048] It should be noted that the above content is a further detailed description of the present invention in combination with specific implementation manners. It cannot be determined that the specific implementation manners of the present invention are limited thereto. Under the guidance of the above embodiments, those skilled in the art can make various improvements and deformations on the basis of the above embodiments, and these improvements or deformations fall within the protection scope of the present invention.

Claims

1. A planar loudspeaker, characterized in that, It includes a diaphragm with its periphery fixed to a frame, and a permanent magnet array composed of a number of permanent magnets. The permanent magnet array is arranged at an interval from the diaphragm and is correspondingly arranged with the coils coated on or embedded in the diaphragm. The permanent magnet has a first end facing the diaphragm and a second end facing away from the diaphragm. A magnetic conductor is arranged near at least the permanent magnet at the middle position of the permanent magnet array. The second ends of two adjacent permanent magnets with opposite magnetic poles can selectively connect to both ends of the magnetic conductor respectively. It also includes a number of magnetic conductor actuators, and each magnetic conductor actuator correspondingly drives one or a group of the magnetic conductors to move towards or away from the second end of the permanent magnet, so that the magnetic conductor connects to or disengages from the second end of the permanent magnet. By controlling different magnetic conductor actuators, the distances between the second ends of the permanent magnets at different positions and the corresponding magnetic conductors are different, and thus the magnetic field intensities generated by the permanent magnets at different positions in the permanent magnet array are different.

2. The planar loudspeaker according to claim 1, wherein The permanent magnets forming the permanent magnet array are evenly distributed.

3. The planar loudspeaker according to claim 1, characterized in that, The permanent magnet array is composed of a number of concentrically nested ring-shaped permanent magnets; or, the permanent magnet array is composed of a number of strip-shaped permanent magnets arranged parallel to each other.

4. The planar loudspeaker according to claim 1, wherein The permanent magnet array has two layers, and the diaphragm is located between the two layers of the permanent magnet array.

5. The planar loudspeaker according to claim 1, characterized in that, The magnetic field intensity generated by the permanent magnet at the middle position of the permanent magnet array is not less than the magnetic field intensity generated by the permanent magnet at the peripheral position of the permanent magnet array.

6. The planar loudspeaker according to claim 1, wherein, The thickness of the permanent magnet at the middle position of the permanent magnet array is less than the thickness of the permanent magnet at the peripheral position of the permanent magnet array.

7. The planar loudspeaker according to claim 6, wherein The second end of the permanent magnet is a plane parallel to the diaphragm, and the distance between the first end of the permanent magnet at the middle position of the permanent magnet array and the diaphragm is greater than the distance between the first end of the permanent magnet at the peripheral position of the permanent magnet array and the diaphragm.

8. The planar loudspeaker according to claim 1, wherein Magnetic conductors are arranged near all the permanent magnets.

9. The planar loudspeaker according to claim 1, characterized in that, Sound guiding holes perpendicular to the diaphragm are arranged at the position of the magnetic conductor between two permanent magnets.

10. The planar loudspeaker according to claim 1, characterized in that, The frame is provided with a guiding hole perpendicular to the diaphragm. The magnetic conductor actuator is a guiding block capable of moving axially along the guiding hole, and the guiding block is fixedly connected with the magnetic conductor along the axial direction of the guiding hole.

11. The planar loudspeaker according to claim 10, characterized in that, The guiding hole is in threaded cooperation with the guiding block, and the rotational movement of the guiding block relative to the guiding hole can cause the guiding block to generate axial movement relative to the guiding hole.

12. The planar loudspeaker according to claim 1, wherein, The second end of the permanent magnet and the end of the magnetic conductor facing the second end are provided with mutually matching clamping structures. When the magnetic conductor is connected to the second end, the clamping structure keeps the permanent magnet and the magnetic conductor in a connected state.

13. The planar loudspeaker according to claim 1, characterized in that, At least the permanent magnet at the middle position of the permanent magnet array is a neodymium iron boron magnet.

14. A headphone having the planar loudspeaker according to any one of claims 1 - 13.

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