Sound head pole plate adopting zirconium oxide coating

Abstract

The utility model relates to the technical field of capacitor microphones, in particular to a sound head polar plate adopting a zirconium oxide coating, which comprises a back polar plate, the vibrating diaphragm is parallel to the back polar plate, and a gap is reserved between the vibrating diaphragm and the back polar plate; and the zirconium oxide coating is arranged on one side surface, close to the vibrating diaphragm, of the back pole plate. Compared with the prior art, the utility model has the advantages that the capacitance of the sound head is obviously increased, and the sensitivity of the sound head is improved. Meanwhile, the film absorbing voltage of the microphone sound head can be increased, the stability of the microphone sound head can be improved, and the sensitivity can be further improved.

Description

Technical Field

[0001] This utility model relates to the field of condenser microphone technology, specifically a microphone electrode plate with a zirconium oxide coating. Background Technology

[0002] Currently, the condenser microphone industry is focused on improving the signal-to-noise ratio and moisture resistance of its products. With advancements in processing technology and material properties, a common practice is to increase capacitance by reducing the distance between the electrodes and the diaphragm. The sensitivity of a microphone capsule is directly proportional to its capacitance; therefore, increasing capacitance also means increasing microphone sensitivity. However, if the distance between the electrodes and the diaphragm is too small, under high polarization voltage, the diaphragm may adhere to the electrodes, causing localized areas to fail to vibrate and thus preventing signal output. Therefore, the key to a well-designed microphone capsule is to maximize capacitance without causing diaphragm adhesion. This means that there are limits to the increase in capacitance.

[0003] The capsule of a condenser microphone is based on the theory of a parallel-plate capacitor. Specifically, it can be understood as two conductive parallel plates separated by a fixed distance *d*, forming a parallel-plate capacitor. The capacitance *C* can be obtained from the following formula:

[0004] ;

[0005] In the formula: ε is the dielectric constant between the two plates. Since the gap between the two plates of the microphone head is air, ε = 1. s is the area of ​​the two plates facing each other. k is the electrostatic constant. d is the distance between the two plates.

[0006] This formula shows that capacitance C is directly proportional to the dielectric constant ε, directly proportional to the plate area S, and inversely proportional to the distance d between the plates. It indicates that increasing capacitance can only be achieved by either reducing the distance d between the two plates or increasing the effective area S of the plates. However, these two parameters are usually already at their limits, so there is no room for further improvement. The capacitance C can also be changed by altering the dielectric constant ε of the air medium between the two plates, but the change in the dielectric constant ε of air is very small.

[0007] Therefore, there is an urgent need to design a microphone plate that can change the dielectric constant of the component to increase the capacitance, thereby improving the microphone capacitance and sensitivity. Utility Model Content

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a microphone electrode plate with a zirconium oxide coating, which changes the structure of the microphone back electrode plate, thereby changing the insulation resistance of the microphone back electrode plate, increasing the insulation impedance of the microphone, and thus increasing the capacitance and diaphragm voltage of the microphone.

[0009] To achieve the above objectives, a microphone electrode plate with a zirconia coating is designed, comprising: a back electrode plate; a diaphragm sheet arranged parallel to the back electrode plate, with a gap between the diaphragm sheet and the back electrode plate; and a zirconia coating disposed on the side of the back electrode plate near the diaphragm.

[0010] Preferably, the present invention further includes: wherein the zirconium oxide coating has a thickness of 0.25-10 micrometers.

[0011] Preferably, the present invention further includes: wherein the zirconium oxide coating is fixed to the side of the back electrode plate near the diaphragm by magnetron sputtering.

[0012] Compared with the prior art, the advantages of this utility model are:

[0013] It significantly increases the capacitance of the microphone capsule, improving its sensitivity. Simultaneously, it can increase the diaphragm voltage of the microphone capsule, contributing to improved capsule stability and further enhancing sensitivity. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model;

[0015] In the diagram: 1. Backplate, 2. Diaphragm, 3. Zirconia coating, 4. External voltage source, 5. Ground. Detailed Implementation

[0016] To make the purpose, principle and structure of this utility model clearer, the following description is provided in conjunction with the accompanying drawings and specific embodiments.

[0017] This invention provides a microphone electrode plate with a zirconia coating, comprising: a pair of parallel back electrode plates 1 and a diaphragm sheet 2, with a gap between the back electrode plates 1 and the diaphragm sheet 2 to form a parallel plate-shaped capacitor. A zirconia coating 3 is provided on the side of the back electrode plate 1 closest to the diaphragm sheet 2.

[0018] The zirconium oxide coating 3 is fixed on the side of the back electrode plate 1 near the diaphragm plate 2 by magnetron sputtering, and its thickness is controlled between 0.25 and 10 micrometers.

[0019] The zirconia coating 3 is disposed on the back electrode plate 1 and is conductive with it. An external voltage source 4 is connected to the back electrode plate 1 via a wire to supply power to it. The diaphragm 2 is connected to a grounding point 5 via a wire.

[0020] When the external voltage source 4 is switched on, the parallel plate capacitor composed of the back plate 1 and the diaphragm 2 begins to charge. During charging, electrons flow from the external voltage source 4 to the back plate 1 and then to the zirconia coating 3, making the back plate 1 and the zirconia coating 3 positively charged, while the diaphragm 2 becomes negatively charged due to induction. Therefore, an electric field is formed between the back plate 1 and the diaphragm 2. When sound waves act on the diaphragm 2, the diaphragm 2 vibrates, causing a change in the distance d between the diaphragm 2 and the back plate 1. Since the charge q, dielectric constant ε, area s of the opposing portions of the back plate 1 and the diaphragm 2, and electrostatic constant k of the parallel plate capacitor remain constant, according to the capacitance formula... The change in distance d causes a change in capacitance C, which in turn affects the voltage V across the capacitor. Ultimately, the change in voltage V reflects the change in sound pressure, thus realizing the conversion from sound signal to electrical signal.

[0021] It is worth noting that the surface oxide layer of the zirconia coating is mainly composed of two compounds: zirconium dioxide (ZrO2) and calcium oxide (CaO). Calcium oxide has significant hydrophilicity, while zirconium dioxide has strong hydrophobicity. Therefore, when the proportion of zirconium dioxide (ZrO2) in the surface oxide layer of the zirconia coating is high, the surface of the zirconia coating exhibits hydrophobic properties; conversely, when the proportion of calcium oxide (CaO) in the surface oxide layer of the zirconia coating is high, the surface of the zirconia exhibits hydrophilic properties. By utilizing the characteristics of the calcium oxide coating, the surface resistance of the zirconia can be controlled to improve the insulation impedance of the microphone plate.

[0022] Zirconia has a dielectric constant that is 30-46 times that of air. According to the capacitance formula, since the capacitance C of the microphone capsule is directly proportional to the dielectric constant, increasing the dielectric constant can increase the capacitance of the microphone capsule. Since zirconia also has high surface and volume resistance at room temperature, adding a zirconia coating to the surface of the electrode plate can not only increase the capacitance of the microphone capsule to improve sensitivity, but also increase the diaphragm voltage of the microphone capsule, as well as improve the stability and sensitivity of the microphone capsule.

[0023] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in this utility model, based on the technical solution and novel concept of this utility model, should be included within the protection scope of this utility model.

Claims

1. A stylus tip plate employing a zirconium oxide coating, characterized by, The application relates to a back electrode plate, a diaphragm plate arranged in parallel to the back electrode plate, and a gap between the back electrode plate and the diaphragm plate. A zirconium oxide coating is arranged on the side of the back electrode plate close to the diaphragm plate. The thickness of the zirconium oxide coating is 0.25-10 microns.

2. A stylus tip plate having a zirconium oxide coating as defined in claim 1, wherein, The zirconium oxide coating is fixed on the side of the back electrode plate close to the diaphragm plate by a magnetron sputtering method.

3. A stylus tip plate having a zirconium oxide coating as defined in claim 1, wherein, ​

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