electrostatic speaker

Abstract

To provide an electrostatic speaker capable of maintaining high fidelity sound quality output even in a wide range of sound. [Solution] The electrostatic speaker includes an electrostatic sound generating diaphragm unit consisting of two parallel, spaced-apart electrode plates (1) and a diaphragm (2) between the electrode plates. The surface of the electrode plate facing the diaphragm is coated with a conductive layer, and both sides of the diaphragm are also coated with conductive layers. A voltage is applied to the conductive layers of the electrode plate and the diaphragm. Hollow sound-emitting holes are uniformly formed in the electrode plate, and an insulating buffer layer (3) is filled between the electrode plate and the diaphragm. Even if the applied high-voltage electric field voltage causes the diaphragm to distort due to excessive amplitude, the insulating buffer layer limits the diaphragm's amplitude, preventing distortion. The insulating buffer layer also prevents contact between the diaphragm and the electrode plate and maintains an appropriate minimum distance, preventing destructive discharges caused by too close a distance between the diaphragm and the electrode plate. This prevents the appearance of high-voltage discharge noise and prevents the diaphragm from being damaged by high-voltage discharge.

Description

[Technical Field]

[0001] The present invention relates to the technical field of electrostatic speakers, and more particularly to electrostatic speakers. [Background technology]

[0002] Speakers are an important sound-generating device in audio playback equipment, directly affecting the quality and expressiveness of audio playback. Most common speakers typically use a vibrating-disk horn as their sound-generating unit. This horn converts audio signals into electromagnetic signals using a coil, which then vibrates a vibrating disk to produce sound. Because the response to high, mid, and low frequencies varies depending on the material of the vibrating disk, different materials are typically used for treble, midrange, and bass horns. However, the distortion rate of vibrating-disk horns is generally high, sometimes reaching 3%, and achieving a distortion rate of less than 1% is extremely difficult. In addition to vibrating-disk horns, commercially available speakers also use electrostatically driven sound-generating units—electrostatic horns. The theoretical distortion rate of these electrostatic horns is only 0.02%, and it is easy to achieve a distortion rate of less than 0.5%. Their typical structure is a capacitor-type structure, with a diaphragm between two sets of fixed electrodes arranged in parallel. When an audio signal is converted into a high-voltage electrical signal and applied between an electrode and a diaphragm, the electric field generated between them drives the diaphragm to vibrate, thereby producing sound. Diaphragms are typically made of very thin membranes, providing excellent transient response characteristics, particularly in the high-frequency range. However, conventional electrostatic speakers on the market typically only meet the needs of high-frequency or mid-high-frequency ranges. While the applicable range can be changed by adjusting the tension of the diaphragm, the overall range remains narrow. Furthermore, to improve the diaphragm's response speed, the distance between the diaphragm and the electrode plate is often small. However, in this case, if the applied high-voltage electric field voltage is too high, the diaphragm's amplitude becomes too large, easily resulting in sound distortion. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention provides an electrostatic speaker that adjusts the design between the electrode plate and the diaphragm to change the gap between them, allowing the diaphragm with the same tension to vibrate and produce sound over a wider range of frequencies, thereby enabling the electrostatic speaker to maintain high-fidelity sound output over a wider range of frequencies. [Means for solving the problem]

[0004] This invention adopts the following technical solutions:

[0005] An electrostatic speaker that includes an electrostatic sound-generating diaphragm unit consisting of two parallel electrode plates arranged at a distance from each other and a diaphragm arranged between the electrode plates, wherein the surface of the electrode plate facing the diaphragm is coated with a conductive layer, and conductive layers are also coated on both sides of the diaphragm, a voltage is applied to the conductive layers of the electrode plate and the diaphragm, hollow sound emission holes are uniformly formed in the electrode plate, and an insulating buffer layer is filled between the electrode plate and the diaphragm.

[0006] The surface of the insulating buffer layer corresponding to the electrode plate is fixed to the surface of the electrode plate.

[0007] The insulating buffer layer is a resilient felt structure.

[0008] The electrode plate is divided into a plurality of sound range response areas, and sound emission holes of different sizes are provided at positions corresponding to the different sound range response areas.

[0009] The electrode plate is divided into a plurality of sound range response areas, and the gap distance between the electrode plate and the diaphragm in the different sound range response areas is set to be different.

[0010] The frequency response areas are arranged from one side of the electrode plate to the other, and the response frequency increases from one side to the other, and the gap distance between the electrode plate and the diaphragm decreases from one side to the other.

[0011] The sound response area exhibits a circular radiation distribution from the center to the edge of the electrode plate, and its response frequency increases from the center to the edge, and the gap distance between the electrode plate and the diaphragm decreases from the center to the edge.

[0012] The frequency response areas are arranged in parallel from one side of the electrode plate to the other, and their response frequencies increase from one side of the electrode plate to the center and then decrease from the center to the other side, and the gap distance between the electrode plate and the diaphragm increases from one side to the center and then decreases from the center to the other side.

[0013] The spacing distance between the electrode plates and the diaphragms of the adjacent range response regions varies gradually.

[0014] The spacing distance between the electrode plates and the diaphragms of the adjacent sound range response regions varies stepwise.

[0015] There are two or more sets of electrostatic sound generation vibrating membrane units, which are arranged closely together in front and behind, with each set of two electrostatic sound generation vibrating membrane units sharing an intermediate electrode plate, and each of the two sides of the intermediate electrode plate being coated with a conductive layer. [Effects of the Invention]

[0016] Beneficial Effects: Compared to conventional electrostatic speakers, the insulating buffer layer between the electrode plate and the diaphragm limits the amplitude of the diaphragm, preventing distortion even when the applied high-voltage electric field causes the diaphragm to have an excessively large amplitude, and the insulating buffer layer prevents contact between the diaphragm and the electrode plate and maintains an appropriate minimum distance, preventing destructive discharges caused by the diaphragm being too close to the electrode plate, avoiding the occurrence of high-voltage discharge noise, and preventing the diaphragm from being damaged by high-voltage discharge. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a structural diagram of an electrostatic speaker according to an embodiment of the present invention; [Figure 2] 1 is a schematic diagram of a hollow structure according to an embodiment of the present invention; [Figure 3] 3 is a schematic diagram of a hollow structure according to another embodiment of the present invention; FIG. [Figure 4] 1 is a structural schematic diagram of an electrostatic speaker according to a first embodiment of the present invention; [Figure 5] 2 is a structural schematic diagram of an electrostatic speaker according to a second embodiment of the present invention; [Figure 6] 1 is a structural schematic diagram of an electrostatic speaker according to a first embodiment of the present invention; [Figure 7] 4 is a structural schematic diagram of an electrostatic speaker according to a fourth embodiment of the present invention. [Figure 8] 1 is a schematic diagram of the circuit structure of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0018] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments. Typically, the components of the embodiments of the present application described and illustrated herein may be arranged and designed in a variety of different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application that requires protection, but merely illustrates selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments that a person skilled in the art can obtain without performing creative work fall within the scope of protection of the present application.

[0020] Like symbols and letters represent like items in subsequent figures, so that once an item is defined in one figure, it need not be further defined or interpreted in subsequent figures.

[0021] In the description of this application, the orientations or positional relationships indicated by the terms "inside," "outside," etc. are based on the orientations or positional relationships shown in the drawings or are the orientations or positional relationships in which the product is always disposed when in use, and are merely for the purpose of simplifying the description of this application, rather than indicating or implying that the specified device or element must be configured or operated in a particular orientation or in a particular direction, and therefore cannot be understood as limitations on this application. Furthermore, the terms "first," "second," etc. are merely for the purpose of distinguishing the description, and are not to be understood as indicating or implying relative importance.

[0022] In the description of this application, unless otherwise clearly specified and limited, the terms "provided" and "connected" should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or an integral connection. They may also refer to a mechanical connection or an electrical connection. They may also refer to a direct connection, an indirect connection via an intermediate medium, or an internal connection between two elements. Those skilled in the art can specifically understand the specific meanings of the above terms in this application.

[0023] The following detailed description will be given in order to clearly and completely explain the technical solutions in the embodiments of the present invention.

[0024] Referring to FIG. 1, a schematic diagram of the structure of an electrostatic speaker according to a first embodiment of the present invention is shown. This electrostatic speaker includes an electrostatic diaphragm unit, a high-voltage generator, and an amplifier. The electrostatic diaphragm unit consists of two parallel electrode plates 1 spaced apart and a diaphragm 2 disposed between the two electrode plates 1. The surfaces of the two electrode plates 1 facing the diaphragm 2 are coated with a conductive layer, and the surface of the diaphragm 2 is also coated with a conductive layer. The output terminals of the high-voltage generator are connected to the two electrode plates 1 and the diaphragm 2, respectively. After being amplified by the amplifier, the audio signal is boosted and polarized by the high-voltage generator. The electric field formed between the conductive layer of the electrode plate 1 and the conductive layer of the diaphragm 2 attracts and pushes the diaphragm 2, causing it to vibrate back and forth, generating sound waves. Typically, the voltage applied between the electrode plate 1 and the diaphragm 2 is 1,000 volts. However, to increase the sensitivity of the diaphragm 2, the distance between the electrode plate 1 and the diaphragm 2 is kept within a few millimeters, and this distance is further reduced as the diaphragm 2 vibrates. In such a high-voltage electric field and close distance, air acts as an insulating medium and is destroyed by the high voltage, affecting the operation of the diaphragm 2 and generating high-voltage discharge noise, which affects sound quality. Furthermore, if the applied high-voltage electric field is too high, the amplitude of the diaphragm 2 may become too large, exceeding the diaphragm 2's set operating range and causing distortion. An insulating buffer layer 3 is filled between the electrode plate 1 and the diaphragm 2, effectively restricting the diaphragm 2 to operate within an appropriate range even if the high-voltage electric field voltage is too high, preventing distortion. Furthermore, this prevents destructive discharges due to the close distance between the diaphragm 2 and the electrode plate 1, thereby preventing the diaphragm 2 from being damaged by high-voltage discharges.

[0025] The insulating buffer layer 3 is provided to restrict the movement of the vibrating membrane 2 within an appropriate range. It must be able to limit the amplitude and prevent noise or damage when the vibrating membrane 2 collides with the insulating buffer layer 3, so the insulating buffer layer 3 must have a certain degree of elasticity. If the voltage of the high-voltage electric field is too high, the amplitude of the vibrating membrane 2 becomes too large and it collides with the insulating buffer layer 3, causing the insulating buffer layer 3 to elastically deform and block the vibrating membrane 2. When the vibrating membrane 2 moves in the opposite direction, the insulating buffer layer 3 recovers. The insulating buffer layer 3 of the present invention preferably has an elastic felt structure, with fluff formed on its surface that has a certain degree of elasticity. When it comes into contact with the vibrating membrane 2, the fluff bends and blocks the vibrating membrane 2. The surface of the felt corresponding to the electrode plate 1 is fixed to the surface of the electrode plate 1.

[0026] Referring to FIG. 2 , the electrode plate 1 is provided with hollow sound holes. The sound holes are preferably mesh-shaped so that sound generated by the vibration of the diaphragm 2 can propagate through the sound holes. Since the design of an electrostatic speaker can meet the sound generation requirements for different frequency ranges, including high, mid, and low frequencies, the diaphragm 2 has different responses in different frequency ranges. Generally, the response of the diaphragm 2 changes from high to low from high to low, thereby achieving different responses with the same diaphragm 2. In this invention, the electrode plate 1 is divided into multiple frequency response ranges, and then structures corresponding to the different frequency response ranges are provided. Specific structures include the size and arrangement of the sound holes 4, the distance between the electrode plate 1 and the diaphragm 2, etc.

[0027] The sound output holes 4 are hollow and formed in the electrode plate 1. They transmit sound emitted from the diaphragm 2 through the sound output holes 4 to the listening position targeted by the electrostatic speaker. The size and arrangement of the sound output holes 4 also affect the electric field strength of the high-voltage electric field between the electrode plate 1 and the diaphragm 2 at that position. The larger the size of the sound output holes 4 and the denser their arrangement, the lower the electric field strength at the corresponding position. Conversely, the smaller the size of the sound output holes 4 and the sparser their arrangement, the higher the electric field strength at the corresponding position. Therefore, by adjusting the size and arrangement of the sound output holes 4 at different positions on the electrode plate 1, different electric field strength distributions can be achieved, thereby forming different sound range response regions. Specifically, at positions with high electric field strength, the driving force on the diaphragm 2 is strong, the diaphragm 2 has a large amplitude and a fast response speed. Conversely, at positions with low electric field strength, the driving force on the diaphragm 2 is weak, the diaphragm 2 has a small amplitude and a slow response speed. Based on these characteristics, by arranging the frequency response areas according to actual needs, an electrostatic speaker can reproduce different frequency ranges, such as high, mid, and low frequencies. For example, at the edge of an electrostatic speaker, the diaphragm 2 is attached to the frame in a taut state, so the tension of the diaphragm 2 is high at this location. By providing small sound emission holes 4 at this location and maintaining a relatively low array density, the electric field strength generated at this location is high and the response speed is fast, thereby improving the reproduction of high-frequency sounds. On the other hand, by providing large sound emission holes 4 at the center of the diaphragm 2 and maintaining a relatively high array density while reducing the tension of the diaphragm 2 with a relatively high array density, the electric field strength generated at this location is weak and the response speed is slow, thereby improving the reproduction of low-frequency sounds. Of course, the above-described configuration of the sound emission holes 4 is not essential, and users can freely arrange the distribution of different frequency response areas according to the above principle.

[0028] The electrode plate 1 and the diaphragm 2 are spaced at different distances from each other. Different distances generate different electric field intensities between the diaphragm 2 and the electrode plate 1. Generally, the smaller the distance, the higher the electric field strength at that location. This results in a more sensitive and larger-amplitude vibration response of the diaphragm 2 at that location, enhancing the response to high-frequency signals and increasing the volume of high-frequency signals. Conversely, the larger the distance, the weaker the electric field strength at that location, reducing the sensitivity of the diaphragm 2 at that location and reducing its amplitude. This makes that location more suitable for generating low-frequency signals. The above-described structure of different distances divides the electrostatic speaker into different frequency response areas, allowing each corresponding frequency response area to have a better response to a corresponding frequency range. Adjusting the distribution of the frequency response areas on the electrode plate 1 improves the overall performance of the electrostatic speaker within different frequency ranges, enabling it to cover a wider frequency range and vibrate and generate sounds over a wider frequency range. This overcomes the limited operating range of conventional electrostatic speakers.

[0029] An electrostatic speaker can create different frequency response areas by changing the distance between the electrode plate 1 and the diaphragm 2 at different positions on the electrode plate 1. By changing the distribution of the frequency response areas, the speaker can respond in different frequency ranges, allowing the user to customize the speaker to meet their hearing needs. In practical applications, the frequency response areas do not need to be physically separated areas on the electrode plate 1, but can be achieved simply by varying the spacing between the electrode plate 1 and the diaphragm 2. Because the spacing between the electrode plate 1 and the diaphragm 2 can be set by smoothly varying it in stages, the different frequency response areas do not need to have clear boundaries. Therefore, the frequency response should not be limited to bounded sound areas.

[0030] The diaphragm 2 of the electrostatic speaker is fixed to the edge of the electrode plate 1 via a holder after an appropriate tension is applied. Since the vibration of the edge of the diaphragm 2 is limited, the response to high frequencies is enhanced. Therefore, the electrode plate 1 and the diaphragm 2 can be provided with a small distance between them at the edge position. This increases the electric field strength between the electrode plate 1 and the diaphragm 2 at this position, thereby improving the amplitude of the diaphragm 2 and meeting the need for high-frequency response. On the other hand, the center of the diaphragm 2 has a large amplitude, so it has good response to low frequencies. Therefore, the distance between the electrode plate 1 and the diaphragm 2 gradually increases from the edge to the center of the electrode plate 1. Specifically, this application provides the following examples for a detailed explanation.

[0031] 4, in the first embodiment, the frequency response areas are arranged from one side to the other of the electrode plate 1, and the response frequency gradually increases from one side to the other, and the distance between the electrode plate 1 and the diaphragm 2 decreases from one side to the other. This design is simple, but it does not achieve the vibration characteristics of the diaphragm 2 at the edge and the diaphragm 2 at the middle.

[0032] 5, in Example 2, the frequency response areas are arranged in parallel from one side to the other of the electrode plate 1, the response frequency increases from one side to the center of the electrode plate 1 and then decreases from the center to the other side, and the gap between the electrode plate 1 and the diaphragm 2 increases from one side to the center and then decreases from the center to the other side. Specifically, the electrode plate 1 also adopts the slope design of Example 1 and is composed of slopes formed inclined from both edges of the electrode plate 1 to the center.

[0033] 6, in the third embodiment, the frequency response area exhibits a circular radiation distribution from the center to the edge of the electrode plate 1, and the response frequency gradually increases from the center to the edge, while the distance between the electrode plate 1 and the diaphragm 2 decreases from the center to the edge. Specifically, by designing each position on the electrode plate 1 and the distance between the electrode plate 1 and the diaphragm 2 according to the distribution of the frequency response area, this is achieved by designing the electrode plate 1 as a slope that gradually slopes from the edge to the center, and adjusting the inclination of the slope at different positions to adjust the distance between the electrode plate 1 and the diaphragm 2.

[0034] 7, in the fourth embodiment, the frequency response area is distributed in a stepped manner from the center to the edge of the electrode plate 1, which causes a corresponding change in the gap between the electrode plate 1 and the diaphragm 2, and the response frequency increases from the center to the edge. Users can design two or more different gaps according to their actual needs to form different frequency response areas.

[0035] Because the electric field strength of the diaphragm 2 is greater at positions where the spacing is narrow, the amplitude generated by driving the diaphragm 2 is larger and the response is sharper, which is advantageous for better response of high-frequency audio signals at this position, i.e., for producing more audio details related to treble, and the larger amplitude makes the treble brighter. Conversely, because the electric field strength of the diaphragm 2 is weaker at positions where the spacing is wide, it is advantageous for producing low-frequency audio signals, i.e., for producing audio in the mid-frequency range, so the mid-range sounds produced at this position are richer and fuller. This design allows the electrostatic speaker to maintain high-fidelity sound quality output over a wide range of frequencies.

[0036] Referring to FIGS. 1, 6, and 7, two or more sets of electrostatic sound diaphragm units are arranged closely together, with each set sharing an intermediate electrode plate 1, each of which is coated with a conductive layer on two sides. A diaphragm 2 is provided between two adjacent electrode plates 1, and the corresponding output terminal of the high-voltage generator is connected to the corresponding electrode plate 1. The conductive layers of the diaphragms 2 have opposite polarities, and the diaphragms 2 vibrate back and forth due to the principle that like charges repel each other and unlike charges attract each other, thereby vibrating the diaphragms 2 to generate sound. In this embodiment, a multi-layer electrode plate 1 structure is used, allowing sounds emitted from adjacent diaphragms 2 under the same frequency conditions to be superimposed, thereby increasing the sound pressure during sound wave transmission and improving sound production efficiency. FIG. 8 is a circuit block diagram of an electrostatic speaker according to a fourth embodiment of the present invention, including an electrostatic sound diaphragm unit, a high-voltage generator 32, and an amplifier 33. The amplifier 33 amplifies the audio signal and then inputs it to the high-voltage generator 32. The high-voltage generator 32 converts the audio signal into a voltage signal of several thousand volts based on the audio signal, and then transmits it to the electrode plate 1 of the electrostatic sound generation diaphragm unit and the conductive layer of the diaphragm.

[0037] It should be pointed out that the above is a preferred embodiment of the present invention, and those skilled in the art can make some improvements and refinements without departing from the principle of the present invention, and these improvements and refinements can also be regarded as within the protection scope of the present invention.

Claims

1. An electrostatic speaker comprising an electrostatic sound-generating diaphragm unit consisting of two parallel electrode plates spaced apart and a diaphragm disposed between the electrode plates, wherein the surface of the electrode plate facing the diaphragm is coated with a conductive layer, and both sides of the diaphragm are also coated with conductive layers, a voltage is applied to the conductive layers of the electrode plate and the diaphragm, hollow sound emission holes are uniformly formed in the electrode plate, and an insulating buffer layer is filled between the electrode plate and the diaphragm.

2. 2. The electrostatic speaker according to claim 1, wherein the surface of the insulating buffer layer corresponding to the electrode plate is fixed to the surface of the electrode plate.

3. 2. The electrostatic speaker of claim 1, wherein the insulating buffer layer is a resilient felt structure.

4. 2. The electrostatic speaker according to claim 1, wherein the electrode plate is divided into a plurality of frequency response areas, and sound emission holes of different sizes and / or different sound emission hole arrangements are provided at positions corresponding to the different frequency response areas.

5. 2. The electrostatic speaker according to claim 1, wherein the electrode plate is divided into a plurality of frequency response areas, and the gap distances between the electrode plate and the diaphragm in different frequency response areas are set to be different.

6. 6. The electrostatic speaker of claim 5, wherein the frequency response areas are arranged from one side of the electrode plate to the other, and the response frequency increases from one side to the other, and the gap distance between the electrode plate and the diaphragm decreases from one side to the other.

7. 6. The electrostatic speaker of claim 5, wherein the frequency response area exhibits a circular radiation distribution from the center to the edge of the electrode plate, and the response frequency increases from the center to the edge, and the gap distance between the electrode plate and the diaphragm decreases from the center to the edge.

8. 6. The electrostatic speaker of claim 5, wherein the frequency response areas are arranged in parallel from one side to the other side of the electrode plate, the response frequency increases from one side to the center of the electrode plate and then decreases from the center to the other side, and the gap distance between the electrode plate and the diaphragm increases from one side to the center and then decreases from the center to the other side.

9. 9. An electrostatic speaker according to claim 6, 7 or 8, wherein the spacing distance between the electrode plates and the diaphragms of the adjacent frequency response regions varies gradually.

10. 9. An electrostatic speaker according to claim 6, 7 or 8, wherein the spacing distance between the electrode plate and the diaphragm in the adjacent frequency response regions varies stepwise.

11. 2. The electrostatic speaker according to claim 1, wherein the electrostatic sound generation diaphragm units are two or more sets, the electrostatic sound generation diaphragm units are arranged closely together in front and behind, and two sets of electrostatic sound generation diaphragm units share an intermediate electrode plate, and two sides of the intermediate electrode plate are each coated with a conductive layer.

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