Ultrasonic speaker

Abstract

An ultrasonic speaker, belonging to the field of electro-acoustic technology. The ultrasonic speaker comprises a magnetic circuit system for providing a magnetic field for the speaker; and a basket configured to be hollow, the magnetic circuit system being fixed in the basket; an FPC fixed to the basket in a lapping manner, the portion of the FPC located on the hollow portion of the basket being elastic; a diaphragm fixed on the FPC in a parallel and fitting manner; a voice coil, the top of the voice coil being fixed on the FPC, and the rest thereof extending into the hollow portion of the basket, and the voice coil being arranged in the basket to vibrate relatively; and an ultrasonic driving element fixed on the FPC and connected to the diaphragm in a fitting manner. When the voice coil is energized, the voice coil drives the diaphragm to vibrate via the FPC to generate a first sound pressure; meanwhile, when the ultrasonic driving element is energized, the ultrasonic driving element drives the diaphragm to vibrate to generate a second sound pressure, and the first sound pressure and the second sound pressure are combined to form an ultrasonic-level frequency response. The ultrasonic speaker of the present invention can achieve the restoration of audio with a higher resolution.

Description

An ultrasonic speaker Technical Field

[0001] The present invention relates to the field of electroacoustic technology, and in particular to an ultrasonic loudspeaker. Background Art

[0002] With the advancement of science and technology and the development of multimedia technology, electronic products are pursuing more convenient operation, faster response, and clearer picture quality, while the requirements for audio quality are also constantly increasing. Existing dynamic speakers mostly consist of a coil and a diaphragm coupled together, as well as a magnet for providing a magnetic field. When the coil is energized, it drives the diaphragm to vibrate together, thereby generating sound. However, the high-frequency frequency response of speakers with this structure is insufficient, which greatly affects the user's listening experience.

[0003] In the prior art, in order to improve the high-frequency response of speakers, piezoelectric drive components have begun to be added to speakers. For example, U.S. patent application publication number US20160219373A1, published on July 28, 2016, discloses a piezoelectric speaker driver. By placing a piezoelectric driver near the speaker, the movement of the piezoelectric driver drives the speaker to vibrate, thereby generating sound energy within a target frequency range, thereby enhancing the target frequency and improving the high-frequency response.

[0004] However, the inventors have discovered that the coupling effect between the piezoelectric driver and the speaker in the above-mentioned structural form is not ideal, and thus cannot accurately restore high-resolution sound sources. Summary of the Invention

[0005] In view of at least one of the above technical problems, the present invention provides an ultrasonic speaker, which adopts structural improvement to improve the frequency response of the speaker.

[0006] According to a first aspect of the present invention, there is provided an ultrasonic speaker comprising:

[0007] A magnetic circuit system for providing a magnetic field for the speaker;

[0008] The basin frame is hollow, and the magnetic circuit system is fixed in the basin frame;

[0009] The FPC is overlapped and fixed on the basin frame, and the hollow portion of the FPC in the basin frame is elastic;

[0010] The diaphragm is fixed parallel to and fitted on the FPC;

[0011] A voice coil, the top of which is fixed to the FPC, and the rest of which extends into the hollow portion of the basin frame, and the voice coil is arranged to vibrate relatively within the basin frame;

[0012] An ultrasonic driving component is fixed on the FPC and is bonded to the diaphragm;

[0013] When the voice coil is energized, the diaphragm is driven to vibrate through the FPC to generate a first sound pressure. At the same time, when the ultrasonic driving component is energized, the diaphragm is driven to generate a second sound pressure. The first sound pressure and the second sound pressure are combined to form an ultrasonic level frequency response.

[0014] In some embodiments of the present invention, the FPC includes an outer frame, an inner frame, and an elastic arm connected between the outer frame and the inner frame. The voice coil is fixed on the inner frame, and the outer frame is fixed on the basin frame.

[0015] In some embodiments of the present invention, the inner frame also has two parallel connecting bridges, and the two ends of the connecting bridges are respectively fixedly connected to the two opposite side frames of the inner frame. The ultrasonic driving component is a piezoelectric piece, and the two ends of the ultrasonic driving component are respectively fixed on the two connecting bridges.

[0016] In some embodiments of the present invention, the portions where the two connecting bridges connect to the ultrasonic driving member are concave, and the depth of the concave is the same as the thickness of the ultrasonic driving member.

[0017] In some embodiments of the present invention, the FPC also has a first circuit for leading out of the ultrasonic driver and a second circuit for leading out of the voice coil. The first circuit is led out from the connecting bridge through the inner frame and the elastic arm to the outer frame, and the second circuit is led out from the inner frame through the elastic arm to the outer frame.

[0018] In some embodiments of the present invention, a reinforcement plate is further provided between the FPC and the diaphragm, one side of the reinforcement plate is bonded to the diaphragm, and the other side of the reinforcement plate is bonded to both the inner frame and the ultrasonic driver.

[0019] In some embodiments of the present invention, the basin frame is further integrally injection-molded with connection electrodes for connecting to the first circuit and the second circuit, and the connection electrodes extend from the upper surface of the basin frame to the lower surface of the basin frame.

[0020] In some embodiments of the present invention, the magnetic circuit system includes a magnet, a magnetic bowl and a pole piece. The magnetic bowl is fixed on the basin frame, and a vibration space for the voice coil to vibrate is formed between the magnetic bowl and the magnet.

[0021] In some embodiments of the present invention, the side wall of the magnetic bowl is folded upward and extends to the plane where the pole piece is located.

[0022] In some embodiments of the present invention, a surface of the pole piece facing the FPC has a groove for the ultrasonic driving member to vibrate.

[0023] The beneficial effects of the present invention are as follows: the present invention fixes both the voice coil and the ultrasonic driver on the FPC, and the FPC is connected to the diaphragm in parallel, so that the vibration of the voice coil and the vibration of the ultrasonic driver are transmitted to the diaphragm through the FPC, thereby making the first sound pressure generated by the vibration of the voice coil and the second sound pressure generated by the vibration of the ultrasonic driver better coupled to form an ultrasonic-level frequency response, thereby achieving the restoration of higher-resolution audio. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] FIG1 is a schematic structural diagram of an ultrasonic speaker according to an embodiment of the present invention;

[0026] FIG2 is a schematic diagram of an exploded structure of an ultrasonic speaker according to an embodiment of the present invention;

[0027] FIG3 is a schematic diagram of the structure of the diaphragm sounding according to an embodiment of the present invention;

[0028] FIG4 is a schematic structural diagram of an FPC according to an embodiment of the present invention;

[0029] FIG5 is a schematic diagram of the connection structure of the FPC, the voice coil and the ultrasonic driver according to an embodiment of the present invention;

[0030] FIG6 is a front view of an FPC according to an embodiment of the present invention;

[0031] 7 is a schematic diagram of the connection structure between the FPC and the reinforcing plate in an embodiment of the present invention;

[0032] FIG8 is a schematic diagram of the connection structure between the basin frame and the magnetic circuit system according to an embodiment of the present invention;

[0033] FIG9 is a schematic diagram of an exploded structure of electrodes connected to a basin frame according to an embodiment of the present invention;

[0034] FIG10 is a schematic diagram of an exploded structure of the connection between the basin frame and the magnetic circuit system according to an embodiment of the present invention;

[0035] FIG11 is a transverse cross-sectional view of the connection between the basin frame and the magnetic circuit system according to an embodiment of the present invention;

[0036] FIG12 is a sound pressure-frequency curve diagram of a conventional speaker and an ultrasonic speaker before and after adding a reinforcement plate in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0038] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly attached to the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0040] As shown in Figures 1 to 11, the ultrasonic speaker includes a magnetic circuit system 1, a basin frame 2, an FPC 3, a voice coil 31, an ultrasonic driver 32, and a diaphragm 4. As shown in Figure 2, the magnetic circuit system 1 is used to provide a magnetic field for the speaker; the energized voice coil 31 vibrates in the magnetic field. It should be noted that the magnetic circuit system 1 has various forms in the prior art, for example, it can be composed of a single main magnetic block or a structure of a main magnetic block and auxiliary magnetic blocks.

[0041] The frame 2 is hollow, and the magnetic circuit system 1 is fixed within the frame 2. In the embodiment of the present invention, the frame 2 not only secures the magnetic circuit system 1, but also provides support for the FPC 3 and the diaphragm 4. During the specific fixation, the FPC 3 and the diaphragm 4 are overlapped and fixed to the edge of the frame 2, and the middle portion can vibrate in the height direction of the frame 2. In addition to securing the above components, the frame 2 also serves as a circuit lead, which is described in detail below.

[0042] In the embodiment of the present invention, FPC3 refers to a flexible printed circuit board, which is overlapped and fixed on the basin frame 2, and the FPC3 is elastic in the hollow part of the basin frame 2; in some embodiments of the present invention, the base material of FPC3 can be made of PI material; in addition to playing the role of circuit transmission in the embodiment of the present invention, FPC3 is more importantly used as a unified vibration source to drive the diaphragm 4. As shown in Figure 2, in the embodiment of the present invention, the diaphragm 4 is fixed on the FPC3 in parallel and fit; and the top of the voice coil 31 is fixed on the FPC3, and the rest of the voice coil 31 extends to the hollow part of the basin frame 2, and the voice coil 31 can be relatively Vibration setting; the ultrasonic driving member 32 is fixed on the FPC3 and is in close contact with the diaphragm 4; that is, as shown in Figure 3, in an embodiment of the present invention, the voice coil 31 is fixed on the bottom of the FPC3, and the ultrasonic driving member 32 is fixed on the FPC3. Through such a setting, the vibration of the diaphragm 4 is transmitted through the FPC3; please refer to the vibration curve in Figure 3. When the diaphragm 4 is driven, when the voice coil 31 is energized, it drives the diaphragm 4 to vibrate through the FPC3 to generate a first sound pressure 100. At the same time, when the ultrasonic driving member 32 is energized, it drives the diaphragm 4 to generate a second sound pressure 200. The first sound pressure 100 and the second sound pressure 200 are combined to form an ultrasonic level frequency response. In the prior art, the ultrasonic driver is either directly attached to the sound diaphragm or arranged near the entire speaker. However, the above fixing methods either have poor vibration transmission effects or cause deformation of the sound diaphragm. There are also problems with connection reliability, resulting in unsatisfactory sound pressure coupling effects. In the embodiment of the present invention, by using FPC3 as a vibration source, the vibration of the voice coil 31 drives the vibration of FPC3, and the ultrasonic driver 32 fixed to FPC3 also drives the vibration of FPC3. Since FPC3 is directly attached to the diaphragm 4, the vibration can be directly transmitted to the diaphragm 4. Moreover, since the ultrasonic driver 32 is fixed to FPC3 and is also clamped between the diaphragm 4 and FPC3, the fixing effect is better.

[0043] In the above embodiment, by fixing the voice coil 31 and the ultrasonic driver 32 on the FPC3, and connecting the FPC3 to the diaphragm 4 in parallel, the vibration of the voice coil 31 and the vibration of the ultrasonic driver 32 are transmitted to the diaphragm 4 through the FPC3, so that the first sound pressure 100 generated by the vibration of the voice coil 31 and the second sound pressure 200 generated by the vibration of the ultrasonic driver 32 are better coupled to form an ultrasonic level frequency response, thereby realizing the restoration of higher resolution audio.

[0044] Based on the above embodiment, in an embodiment of the present invention, the specific structure of FPC 3 is shown in Figure 4. FPC 3 includes an outer frame 3a, an inner frame 3b, and an elastic arm 3c connected between the outer frame 3a and the inner frame 3b. The voice coil 31 is fixed to the inner frame 3b, and the outer frame 3a is fixed to the basin frame 2. The connection of the elastic arm 3c enables the inner frame 3b to vibrate up and down relative to the plane of the outer frame 3a. It should be noted that in some embodiments of the present invention, the elastic arm 3c can have various structural forms, including the S-shaped elastic arm 3c shown in Figure 4, or other structural forms.

[0045] In an embodiment of the present invention, the ultrasonic driving element 32 is a piezoelectric sheet. However, according to the characteristics of the ceramic piezoelectric sheet, when the planned direction and the excitation electric field of the long sheet-shaped ceramic piezoelectric sheet are both along the thickness direction of the long sheet, the vibration generated by the ceramic piezoelectric sheet is a transverse stretching vibration, that is, stretching vibration along the length direction of the piezoelectric sheet. If the ceramic piezoelectric sheet is directly attached to the diaphragm 4 in this vibration form, the diaphragm 4 will be deformed in the length direction and will not be able to provide a vibration effect in the thickness direction. In an embodiment of the present invention, in order to convert the stretching vibration of the piezoelectric sheet in the length direction into vibration in the thickness direction, as shown in Figures 4 and 5, the inner frame 3b also has two parallel connecting bridges 3b1, and the two ends of the two connecting bridges 3b1 are respectively fixedly connected to the two opposite side frames of the inner frame 3b, and the two ends of the ultrasonic driving element 32 are respectively fixed on the two connecting bridges 3b1. By fixing the two ends of the piezoelectric piece and leaving the middle part suspended, the stretching vibration of the piezoelectric piece can be changed to a convex and concave vibration in the thickness direction of the piezoelectric piece. That is, by fixing the two ends of the piezoelectric piece, the stretching vibration of the piezoelectric piece in the length direction is converted to bending vibration in the thickness direction, thereby achieving better vibration transmission;

[0046] Based on the above embodiment, in the embodiment of the present invention, referring to Figures 3 to 5 , the portions where the two connecting bridges 3b1 connect to the ultrasonic driver 32 are recessed, with the depth of the recess being the same as the thickness of the ultrasonic driver 32. This structural arrangement allows the upper surface of the piezoelectric sheet to be flush with the upper surface of the inner frame 3b, thereby better achieving vibration transmission in the thickness direction.

[0047] In an embodiment of the present invention, in addition to the aforementioned functions of vibration transmission, piezoelectric plate vibration mode conversion, and fixation, FPC3 also serves as a wiring lead. Specifically, as shown in Figure 6, FPC3 also includes a first wiring lead 3d for the ultrasonic driver 32 and a second wiring lead 3f for the voice coil 31. The first wiring lead 3d extends from the connecting bridge 3b1 through the inner frame 3b and the elastic arm 3c to the outer frame 3a, while the second wiring lead 3f extends from the inner frame 3b through the elastic arm 3c to the outer frame 3a. During connection, the lead-in and lead-out wires for the voice coil 31 are located at both ends of the length, connecting to the second wiring lead 3f at both ends of the length of the inner frame 3b, eliminating the need for external wiring to lead out the voice coil 31. The ultrasonic driver 32 is fixed to the connecting bridge 3b1 by welding and then leads to the edge of the outer frame 3a via the first wiring lead 3d. It should be noted that in some embodiments of the present invention, both the first wiring lead 3d and the second wiring lead 3f are printed on the FPC3 substrate.

[0048] Continuing with reference to Figures 3 and 7, in an embodiment of the present invention, a reinforcement plate 33 is further provided between the FPC 3 and the diaphragm 4. One side of the reinforcement plate 33 is bonded to the diaphragm 4, and the other side of the reinforcement plate 33 is bonded to both the inner frame 3b and the ultrasonic driver 32. In an embodiment of the present invention, the additional plate is made of a material with a relatively high hardness, such as a stainless steel plate. By placing the high-hardness material between the FPC 3 and the diaphragm 4, the frequency response of the diaphragm 4 can be improved. As shown in Figure 12, the frequency response of the ultrasonic speaker with the reinforcement plate 33 added in the embodiment of the present invention achieves an ultra-wideband frequency, with high frequencies reaching over 40kHz. With this arrangement, in the ultrasonic speaker of the present invention, the voice coil 31 is responsible for low and mid-frequency reproduction, and the piezoelectric plate compensates for the deficiencies of the voice coil 31 in the mid- and high-frequency regions. When the sound is played out, the high-frequency timbre of the human voice is rich, full, transparent, and impactful, making the sound more shocking.

[0049] As shown in Figures 8 and 9 , in this embodiment of the present invention, connection electrodes 21 for connecting to the first and second circuits 3d and 3f are integrally molded onto the frame 2. These electrodes 21 extend from the upper surface of the frame 2 to the lower surface. This arrangement allows the FPC 3, when attached to the frame 2, to communicate with the connection electrodes 21, thereby routing the circuits to the four corners of the frame 2's bottom. This arrangement further reduces the space occupied by the speaker.

[0050] In an embodiment of the present invention, the specific structure of magnetic circuit system 1 is shown in Figures 10 and 11. Magnetic circuit system 1 includes a magnet 11, a magnetic bowl 12, and a pole piece 13. Magnetic bowl 12 is fixed to frame 2, and a vibration space is formed between magnetic bowl 12 and magnetic steel 11 for the vibration of voice coil 31. This creates a space for the up-and-down vibration of voice coil 31 between the inner wall of magnetic bowl 12 and the outer walls of magnetic steel 11 and pole piece 13, which not only uniformizes the magnetic field intensity but also further reduces space usage.

[0051] In an embodiment of the present invention, the structure of the magnetic bowl 12 is further improved. Referring to Figures 10 and 11 , the sidewalls of the magnetic bowl 12 are folded upward and extend to the plane where the pole piece 13 is located. By folding the sidewalls of the magnetic bowl 12, the magnetic induction lines on the magnet 11 are guided through the magnetic bowl 12 to the upper surface close to the pole piece 13. A stronger magnetic field is then formed between the pole piece 13 and the upper surface of the sidewalls of the magnetic bowl 12, thereby providing a better magnetic field foundation for the vibration of the voice coil 31. This configuration of the magnetic bowl 12 also reduces the generation of magnetic leakage.

[0052] Based on the above embodiment, referring to FIG10 , in this embodiment of the present invention, the surface of the pole piece 13 facing the FPC 3 has a groove 13a for the ultrasonic driver 32 to vibrate. The provision of the groove 13a leaves space below for the ultrasonic driver 32 to vibrate. Of course, it should be noted that in this embodiment of the present invention, the driver can vibrate in either the two-end vibration mode or the middle vibration mode, and both of these vibration modes fall within the scope of protection of the present invention.

[0053] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An ultrasonic loudspeaker, characterized in that, Comprising: A magnetic circuit system for providing a magnetic field for the speaker; A chassis, which is hollow, and the magnetic circuit system is fixed inside the chassis; An FPC, which is lapped and fixed on the chassis, and the part of the FPC in the hollow part of the chassis is elastic; A diaphragm, which is fixedly attached to the FPC in parallel; A voice coil, the top of which is fixed on the FPC, and the rest extends into the hollow part of the chassis, and the voice coil is arranged to be relatively vibratable inside the chassis; An ultrasonic driver, which is fixed on the FPC and is attached to the diaphragm; Wherein, when the voice coil is energized, it drives the diaphragm to vibrate through the FPC to generate a first sound pressure, and at the same time the ultrasonic driver is energized to drive the diaphragm to generate a second sound pressure, and the first sound pressure and the second sound pressure are combined to form an ultrasonic-level frequency response.

2. The ultrasonic loudspeaker according to claim 1, wherein The FPC includes an outer frame, an inner frame and elastic arms connecting the outer frame and the inner frame, the voice coil is fixed on the inner frame, and the outer frame is fixed on the chassis.

3. The ultrasonic loudspeaker according to claim 2, wherein There are also two parallel connecting bridges on the inner frame, and the two ends of the two connecting bridges are respectively fixedly connected to the opposite side frames of the inner frame. The ultrasonic driver is a piezoelectric sheet, and the two ends of the ultrasonic driver are respectively fixed on the two connecting bridges.

4. The ultrasonic speaker according to claim 3, characterized in that, The parts of the two connecting bridges connected to the ultrasonic driver are recessed, and the recessed depth is the same as the thickness of the ultrasonic driver.

5. The ultrasonic loudspeaker according to claim 3, wherein The FPC also has a first circuit for leading out the ultrasonic driver and a second circuit for leading out the voice coil. The first circuit is led out from the connecting bridge through the inner frame and the elastic arms to the outer frame, and the second circuit is led out from the inner frame through the elastic arms to the outer frame.

6. The ultrasonic loudspeaker according to claim 3, characterized in that, There is also a reinforcing plate between the FPC and the diaphragm. One side of the reinforcing plate is attached to the diaphragm, and the other side of the reinforcing plate is simultaneously attached to the inner frame and the ultrasonic driver.

7. The ultrasonic speaker according to claim 5, wherein The chassis is also integrally injection-molded with connecting electrodes for connecting with the first circuit and the second circuit, and the connecting electrodes extend from the upper surface of the chassis to the lower surface of the chassis.

8. The ultrasonic speaker according to claim 1, wherein, The magnetic circuit system includes a magnet, a magnetic bowl and a pole piece. The magnetic bowl is fixed on the chassis, and a vibration space for the voice coil to vibrate is formed between the magnetic bowl and the magnet.

9. The ultrasonic speaker according to claim 8, wherein, The side wall of the magnetic bowl is turned up and extends to the plane where the pole piece is located.

10. The ultrasonic speaker according to claim 8, wherein, The pole piece has a groove for the ultrasonic driver to vibrate on the surface facing the FPC.

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