An electret microphone amplifier with in-vivo die positioning assembly

Abstract

This utility model relates to an electret microphone amplifier with an internal die positioning assembly. The inner half of the cavity has a positioning groove for fitting the die, a through groove at the bottom of the cavity, a vertically oriented recessed groove on the front wall of the cavity, an electrode mounting groove at the top of the cavity for mounting an electrode, and a concave cavity at the bottom of the cavity. A circuit board is located at the bottom of the cavity, and components on the circuit board are located within the concave cavity at the bottom of the cavity. The source and drain of the die are soldered to the circuit board through the through groove at the bottom of the cavity. The gate of the die is located at the top of the die after being bent three times at 90° from the bottom, making elastic contact with the bottom surface of the electrode. The advantage of this utility model is that it utilizes the cavity structure and die pins to achieve three-stage die positioning: the first positioning groove positions the die, the second positioning is achieved by the bend of the middle gate pin through the through groove, and the third positioning is achieved by the concave cavity at the bottom of the cavity for the components on the printed circuit board.

Description

Technical Field

[0001] This utility model relates to the design improvement of commonly used electret microphone amplifiers, and in particular to an electret microphone amplifier with internal die positioning and assembly. Background Technology

[0002] Electret microphones are essential basic electroacoustic devices used in various electronic products, components, and other applications both domestically and internationally, and have been widely adopted in many fields. Currently, these devices are mainly divided into two categories: one is medium-to-large-sized products manufactured using traditional processes. Aside from a small number of 12mm and larger models specifically designed for use with built-in microphone capsules, these mainly include products with dimensions such as 9.7mm and 6.0mm; the other is surface-mount micro-sized products, used for applications such as external earphones for mobile phones. Compared to the latter, the former, though fewer in number, boasts superior technical performance in fundamental electroacoustic parameters such as frequency response, sensitivity, and signal-to-noise ratio. However, because its original amplifier cavity and other structures are largely fixed, it cannot accommodate the addition of resistors and capacitors to eliminate ultra-high frequency interference signals, provide anti-static properties, or increase gain, unlike the latter. Consequently, its application range tends to be limited. Furthermore, due to the lack of significant changes in conventional product design over the past 40 years, amplifier manufacturing remains primarily manual, with processes such as bending and shearing standard-shaped tube cores and spot welding between electrode plates and pins requiring substantial time. In addition, the large number of manufacturers has led to fierce price competition, with some factories substituting iron for copper in structural components such as electrode plates and diaphragm rings. This inevitably results in shortened product lifespan, increased noise, and other drawbacks, ultimately affecting the microphone's stability and reliability. Commonly used electret microphones urgently need to be reformed to keep pace with the times, especially focusing on the structure of their "heart"—the amplifier. If an innovative electret microphone amplifier can be designed that saves labor, simplifies the process, and ensures that the product's technical performance is not reduced, and some operating procedures are mechanized, and its functionality and adaptability are expanded by adding internal circuit components, it will surely be welcomed by most manufacturing plants. Summary of the Invention

[0003] This invention addresses the shortcomings of existing microphone structures by providing an electret microphone amplifier with an internal die positioning assembly. The amplifier comprises a cavity, electrode plates, a die, and a circuit board. Its features include a positioning groove on the inner half of the cavity for fitting the die, a through groove at the bottom of the cavity, a vertically recessed groove on the front wall of the cavity, an electrode plate mounting groove at the top of the cavity, an electrode plate embedded in the mounting groove, and a concave cavity at the bottom of the cavity. The circuit board is located at the bottom of the cavity, and the components on the circuit board are located within the concave cavity at the bottom of the cavity. The source and drain of the die are welded to the circuit board through the through groove at the bottom of the cavity. The gate of the die is located at the top of the die after being bent three times at 90° from the bottom. The middle section of the gate is located in the groove on the front wall of the cavity. The gate at the top of the die is in elastic contact with the bottom surface of the electrode plate embedded in the electrode plate mounting groove at the top of the cavity. A straight cut is made on the bottom surface of the cavity. The die installed in the positioning groove, along with the distance between its gate lead thickness and the plate mounting groove, and the micro-elasticity formed by the naturally left gap, ensures that the gate and the plate are always connected, thus completely eliminating the spot welding process between the gate and the plate of the existing die.

[0004] The advantages of this utility model are: (1) It abandons the common mode of placing the universally shaped die at any position in the cylindrical cavity of the microphone amplifier. According to the acoustic principle, a positioning groove matching the die shape is specially designed in the cavity to achieve the primary positioning of the die. (2) After the die is installed in the positioning groove of the cavity, the middle gate pin is placed in the tube body after being bent three times at 90°. The natural micro-elasticity of the gate pin is used to ensure that it is in reliable contact with the bottom surface of the electrode plate in the electrode plate mounting groove. This completely changes the existing die and electrode plate spot welding connection method and achieves the secondary positioning of the die in the cavity. (3) It is closely aligned with the bottom plane of the common specification amplifier cavity and the PCB board. Unlike conventional amplifiers, this one features a recessed cavity on the bottom surface of the cavity. The perimeter of the recessed cavity can be attached to a standard single-sided PCB, but there is an empty space in the middle. The source and drain leads of the die pass through the through slot at the bottom of the cavity and are fixed to the lead surface of the single-sided PCB by soldering. This gives it the same function as a commonly used amplifier. If a double-sided PCB with mounted circuit design components is used, its perimeter can be positioned and attached to the perimeter of the recessed cavity and fixed to the lead surface of the PCB by soldering. The recessed cavity can be used to place specialized circuit components on the inner circular surface of the PCB for eliminating external signal interference, anti-static purposes, increasing gain, etc., thereby achieving three-dimensional positioning within the amplifier. Attached Figure Description

[0005] Figure 1 This is a top view of the cavity structure of this utility model.

[0006] Figure 2 This is a side sectional view of the cavity structure of this utility model.

[0007] Figure 3 This is a schematic diagram of the structure of the present invention, which includes a core, a circuit board, and an electrode plate. Detailed Implementation

[0008] See Figures 1-3 An electret microphone amplifier with in-body die positioning and assembly includes a cavity 1, an electrode plate 2, a die 3, and a circuit board 4. Its features include a positioning groove 5 for fitting the die on the inner half of the cavity, a through groove 6 at the bottom of the cavity, a vertically recessed groove 7 on the front wall of the cavity, an electrode plate mounting groove 8 at the top of the cavity, an electrode plate being embedded in the mounting groove, a concave cavity 9 at the bottom of the cavity, and the circuit board located at the bottom of the cavity. Components 13 on the circuit board are located within the concave cavity at the bottom of the cavity. The source electrode 10 and drain electrode 10 of the die are located within the concave cavity at the bottom of the cavity. Figure 3 (The source electrode 10 is obscured and not shown) is soldered to the circuit board through a through slot at the bottom of the cavity. The gate electrode 12 is located at the top of the die after being bent three times at 90° from the bottom of the die. The middle section of the gate electrode is located in a recess on the front wall of the cavity. The gate electrode at the top of the die is in elastic contact with the bottom surface of the electrode plate embedded in the electrode plate mounting slot at the top of the cavity. A straight cut 11 is provided on the bottom surface of the cavity. The die electrode installed in the positioning groove, together with the thickness of its gate lead and the distance between the electrode plate mounting slot and the naturally left gap, forms a micro-elastic force, which ensures that the gate electrode and the electrode plate are always in communication.

[0009] In actual production, based on the amplifier demand, several amplifier three-piece assembly machines are manufactured to automatically assemble the injection-molded cavity (hereinafter referred to as the cavity), die, and electrode plate mechanically. Its main assembly and functions include:

[0010] 1. Three vibratory feeders are essential: one is used to feed the core to the first station and bend the middle pin of the core by 180 degrees; the second is used to feed the plastic cavity to the second station and use the straight cut on the bottom of the cylindrical plastic cavity to make it neatly arranged to meet the positioning and assembly requirements; the third is used to feed the electrode plate to the third station to complete the flattening operation of the three-piece electrode plate.

[0011] 2. The three stations of the assembly machine are responsible for their respective positioning and assembly tasks: The first station bends the middle pin of the core to 180 degrees and is then sent to the second station by the first propulsion device on the machine. Here, it meets the plastic cavity that has arrived earlier and is waiting in place. It is then pneumatically lifted and accurately placed into the positioning groove inside the cavity. The plastic cavity and the core assembly are sent to the third station by the second propulsion device on the machine. At this time, a flattening device on the machine aims at the middle pin of the core and performs a 90-degree bend (due to the inevitable rebound after the application of micro-elastic force, it may only be bent to about 80 degrees). The electrode plate, which is lifted from the feeding vibratory plate by the pneumatic device, is simultaneously sent to the top of the third station and aligned with the electrode plate mounting groove on the top of the plastic cavity. The electrode plate is embedded in the electrode plate mounting groove by the mechanical pressing device and is then covered by the timely arriving clamping device and sent to the discharge track. The essential clamping device applies force to the plate surface for a certain period of time to eliminate the residual micro-elastic force after the plate is bent 90 degrees twice, so that it cannot bulge out of the groove and fall off.

[0012] 3. The amplifier components are manually inserted onto the PCB. After that, the components are flipped over and sent to a general soldering machine to solder the pins one by one according to the input program. After the PCB is soldered, it is unloaded and the entire processing is completed.

[0013] Given the high difficulty and precision required in manufacturing the three-piece kit, it is conceivable to manufacture individual units at separate workstations, or to still use manual labor for some operations; however, as mentioned above, the bending process of the middle pin of the die directly affects the frequency response and sensitivity matching rate of the amplifier and even the electret microphone, so it is not advisable to use manual replacement.

[0014] Because the plastic cavity can smoothly enter the automatic vibrating feeder and be neatly arranged in the three-piece assembly, a straight cut must be made on the bottom surface of the plastic cavity.

Claims

1. An electret microphone amplifier with in-vivo die positioning assembly, comprising a cavity, a plate, a die and a circuit board, characterized in that, The cavity has a positioning groove for fitting the die on the inner half, a through groove at the bottom of the cavity, a vertical groove on the front wall of the cavity, a plate mounting groove at the top of the cavity, a plate being installed in the plate mounting groove, and a concave cavity at the bottom of the cavity. The circuit board is located at the bottom of the cavity, and the components on the circuit board are located in the concave cavity at the bottom of the cavity. The source and drain of the die are soldered to the circuit board through the through groove at the bottom of the cavity. The gate of the die is located at the top of the die after being bent three times at 90° from the bottom of the die. The middle section of the gate is located in the groove on the front wall of the cavity. The gate at the top of the die is in elastic contact with the bottom surface of the plate installed in the plate mounting groove at the top of the cavity.

2. The electret microphone amplifier with in-body die positioning and assembly according to claim 1, characterized in that, A straight cut is made on the bottom surface of the cavity.

3. The electret microphone amplifier with in-body die positioning and assembly according to claim 1, characterized in that, The die installed in the positioning groove, along with the distance between its gate pin thickness and the plate mounting groove, and the micro-elasticity formed by the naturally left gap, ensures that the gate and the plate are always in communication.

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