Microphone screening equipment
By designing a microphone screening device including test fixtures, down-voltage motors and control devices, the problem of dirt and poor performance in the prior art is solved, and a higher test accuracy and production yield is achieved.
Patent Information
- Application Number
- CN202421061591.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-16
- Publication Date
- 2025-03-07
- Estimated Expiration
- 2034-05-16
AI Technical Summary
It is difficult for the prior art to accurately screen out slight dirt, foreign matter and poor performance silicon microphones in MEMS chips.
A microphone screening device is designed, including test fixtures, down-voltage motors, test lower needle holders, test upper needle holders, drive devices and control devices. The device realizes sealing and accommodating the target microphone and sound pressure testing through the speaker sound, pressing the test needle and driving the control device, and selects qualified microphones.
It improves the accuracy of testing problems of MEMS chips for dirt, foreign objects and poor performance, avoids the outflow of minor defective products, and improves the yield of production.
Smart Images
Figure CN222582597U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of acoustic devices, and in particular to a microphone screening device. Background Art
[0002] MEMS (micro electro mechanical systems) microphones are microphones made based on MEMS technology. They are physically picked up by silicon structural materials and processed by "silicon circuits", so they are also called silicon microphones. Generally, silicon microphones are mainly composed of MEMS chips, ASIG (Application Specific Integrated Circuit) chips, substrates, and shells.
[0003] In the existing technology, the manufacturing process of silicon microphones cannot avoid a small amount of dust and other dirt entering the MEMS chip cavity, causing damage to the performance and appearance of the MEMS chip. The currently commonly used manual inspection methods cannot accurately screen out abnormal products such as slight MEMS chip dirt, foreign matter and output distortion. Summary of the invention
[0004] The main technical problem solved by the present application is to provide a microphone screening device.
[0005] The microphone screening device proposed in the present application includes: a test fixture, a test sound cavity is formed inside the test fixture, and a speaker is arranged in the test sound cavity; a downward pressure motor is arranged above the test fixture; a test lower needle seat is arranged on the test fixture and has a placement groove for accommodating a target microphone; a test upper needle seat is connected to the downward pressure motor, has a test needle for contacting the target microphone, can move under the drive of the downward pressure motor, and when pressed down onto the test lower needle seat, forms a sealed accommodating cavity for accommodating the target microphone with the test lower needle seat, and the sealed accommodating cavity is connected to the test sound cavity; a driving device is used to drive the speaker to sound; a control device is connected to the driving device, the downward pressure motor and the test upper needle seat, and is used to control the driving device to drive the speaker to sound, control the downward pressure motor to drive the test upper needle seat to be pressed down onto the test lower needle seat, and test and screen the target microphone by taking the test needle of the test upper needle seat.
[0006] In some optional embodiments, the test lower needle holder includes 16 placement grooves for placing 16 target microphones, and the control device is configured to complete the test screening of the 16 target microphones at one time.
[0007] In some optional implementations, a standard microphone is further provided in the test sound cavity, and the standard microphone is used to monitor whether the sound emitted by the speaker meets the requirements.
[0008] In some optional embodiments, the test sound cavity is divided into a front cavity and a rear cavity, the speaker is installed in the rear cavity and emits sound to the front cavity, the standard microphone is installed in the front cavity, and the front cavity is connected to the sealed containing cavity.
[0009] In some optional implementations, the target microphone is a silicon microphone or an electret condenser microphone.
[0010] In some optional embodiments, a sound hole connecting the test sound cavity and the sealed accommodating cavity is opened on the test lower needle seat, and the sound hole includes: a first sound hole formed inside the placement groove; and / or a second sound hole formed outside the placement groove.
[0011] In some optional embodiments, the driving device includes: a test sound card, configured to connect to an external sound source and convert and process the sound signal emitted by the external sound source; a power amplifier, connected to the test sound card, configured to amplify the sound signal converted and processed by the test sound card, and output the amplified sound signal to the speaker to drive the speaker to make sound.
[0012] In some optional implementations, the control device is configured to screen out qualified microphones by testing the distortion, sensitivity and maximum sound pressure level AOP of the target microphone.
[0013] In some optional embodiments, the control device is configured to screen out qualified microphones by testing the distortion difference of adjacent sweep sound pressure points of the target microphone, the sensitivity difference between two tests under the same sound pressure, and the maximum sound pressure level AOP.
[0014] In some optional embodiments, the control device is configured to perform the following steps: performing a swept sound pressure comparison test on the target microphone, including: testing the distortion of the target microphone at multiple swept sound pressure points, determining whether the distortion corresponding to each swept sound pressure point exceeds a set range, and performing a difference comparison on the distortion of two adjacent swept sound pressure points to confirm whether the corresponding distortion difference exceeds the set range, thereby screening out qualified target microphones; performing a high sound pressure test on the qualified target microphone screened out in the previous step, including: testing the first sensitivity of the target microphone under a first preset sound pressure, and then testing the first sensitivity of the target microphone under a second preset sound pressure. Set the second sensitivity under the sound pressure, and then test the third sensitivity of the target microphone under the first preset sound pressure again, wherein the first preset sound pressure is lower than the second preset sound pressure, calculate whether the sensitivity difference between the first sensitivity and the third sensitivity exceeds the set range, so as to screen out qualified target microphones; perform a fixed distortion sound pressure test on the qualified target microphone screened out in the previous step, including: testing to determine the maximum sound pressure level AOP of the target microphone, AOP is the sound pressure corresponding to 10% distortion of the output of the target microphone at 1KHz, and determine whether the AOP is lower than the control sound pressure level, so as to screen out qualified target microphones.
[0015] In some optional embodiments, the test to determine the maximum sound pressure level AOP of the target microphone includes: using the distortion of the target microphone at multiple swept sound pressure points obtained in the step of performing the swept sound pressure comparison test on the target microphone to determine the maximum sound pressure level AOP of the target microphone.
[0016] In some optional embodiments, the distortion of the test target microphone at multiple swept sound pressure points includes: total harmonic distortion THD of the swept test target microphone at multiple swept sound pressure points from 94 dB to 130 dB, wherein the interval between adjacent swept sound pressure points is 3 dB.
[0017] In some optional embodiments, the first preset sound pressure is 94 dB, and the second preset sound pressure is 130 dB.
[0018] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:
[0019] The test screening equipment of the present application includes a test fixture, a downward pressure motor, a test lower needle holder, a test upper needle holder, a drive device and a control device, etc., which can realize the test screening of the target microphone, and can be used to test the problems of dirt, foreign matter and poor performance of the silicon microphone MEMS chip, and screen out qualified microphones. Compared with the prior art, the present application improves the test accuracy of MEMS chip dirt, foreign matter and poor performance, avoids the outflow of slightly defective products, and improves the test screening efficiency and production yield. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments and the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0021] Figure 1 is a schematic diagram of the structure of a microphone screening device according to the present application;
[0022] Figure 2 is a three-dimensional diagram of a test fixture of a microphone screening device of the present application;
[0023] Figure 3 is a front view of a test fixture of a microphone screening device of the present application;
[0024] Figure 4 is a flow chart of test screening steps of a microphone screening device according to the present application;
[0025] Figure 5 It is a specific operation flow chart of a microphone screening device according to the present application. DETAILED DESCRIPTION
[0026] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only embodiments of a part of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.
[0027] The terms "first", "second", "third", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.
[0028] The following describes the embodiments in detail.
[0029] Please refer to Figures 1 to 3 , Figure 1is a schematic diagram of the structure of a microphone screening device according to the present application, Figure 2 and Figure 3 They are respectively a stereoscopic view and a front view of the test fixture of the microphone screening equipment.
[0030] like Figures 1 to 3 As shown, the microphone screening device of the present application includes:
[0031] A test fixture 21, wherein a test sound cavity is formed inside the test fixture 21, and a speaker is arranged in the test sound cavity;
[0032] A downward pressing motor 22 is arranged above the test fixture 21;
[0033] The test lower needle seat 23 is arranged on the test fixture 21 and has a placement groove 231 for accommodating the target microphone;
[0034] The upper test needle holder 24 is connected to the pressing motor 22, has a test needle for contacting the target microphone, can move in the vertical direction under the drive of the pressing motor 22, and forms a sealed accommodating cavity for accommodating the target microphone with the lower test needle holder 23 when pressed down onto the lower test needle holder 23, and the sealed accommodating cavity is communicated with the test sound cavity;
[0035] A driving device, used for driving the speaker to sound;
[0036] The control device 27 is connected with the driving device, the pressing motor 22 and the testing upper needle seat 23, and is used to control the driving device to drive the speaker to sound, control the pressing motor 22 to drive the testing upper needle seat 23 to press down onto the testing lower needle seat 23, and perform a screening test on the target microphone through the testing of the testing upper needle seat 23;
[0037] Here, the control device 27 may be configured to test the distortion, sensitivity and maximum sound pressure level AOP of the target microphone, and screen out qualified microphones according to the test results.
[0038] In some optional embodiments, the test lower needle seat 23 includes 16 placement grooves for placing 16 target microphones to form 16 test channels, and the control device 27 is configured to complete the test screening of the 16 target microphones at one time.
[0039] In some optional implementations, a standard microphone (i.e., a standard microphone stick) is also provided in the test sound cavity, and the standard microphone is used to monitor whether the sound emitted by the speaker meets the requirements and is stable.
[0040] In some optional embodiments, the test sound cavity is divided into a front cavity and a rear cavity, the speaker is installed in the rear cavity and emits sound to the front cavity, the standard microphone is installed in the front cavity, and the front cavity is connected to the sealed containing cavity.
[0041] In some optional implementations, the target microphone is a silicon microphone or an electret condenser microphone.
[0042] In some optional implementations, the test fixture is provided with a speaker interface to facilitate electrical connection to the speaker. For example, the driver device can be connected to the speaker through the speaker interface.
[0043] In some optional implementations, the test fixture is provided with a standard microphone interface (i.e., a standard microphone interface) to facilitate electrical connection to a standard microphone. For example, the control device can be connected to the standard microphone through the standard microphone interface.
[0044] In some optional implementations, a sound hole connecting the test sound cavity and the sealed accommodating cavity is provided on the test lower needle seat 23, and the sound hole may include:
[0045] A first sound hole is formed inside the placement groove 231 so that the sound emitted by the speaker in the test sound cavity acts on the first surface of the target microphone in the placement groove 231 through the first sound hole;
[0046] And / or, a second sound hole is formed outside the placement groove so that the sound emitted by the speaker in the test sound cavity acts on the second surface of the target microphone in the placement groove 231 through the second sound hole and the sealed accommodating cavity, and the second surface is opposite to the first surface.
[0047] In some optional embodiments, the driving device includes a test sound card 25 and a power amplifier 26;
[0048] The test sound card 25 is configured to connect to an external sound source and convert the sound signal emitted by the external sound source; the conversion process includes but is not limited to digital-to-analog conversion, that is, converting the digital sound signal into an analog sound signal;
[0049] The power amplifier 26 is connected to the test sound card 25, and is configured to amplify the sound signal converted and processed by the test sound card 25, and output the amplified sound signal to the speaker to drive the speaker to produce sound.
[0050] In some optional embodiments, the microphone screening device of the present application also includes a main housing 20 for carrying a test fixture 21 , a downward pressure motor 22 , a test lower needle seat 23 , a test upper needle seat 24 , a drive device and a control device 27 .
[0051] In some optional embodiments, a test space for accommodating the test fixture 21, the lower test needle seat 23, and the upper test needle seat 24 is formed inside the main housing 20. The test space may be a closed space. The test space may have an openable door to facilitate the placement or removal of the target microphone.
[0052] In some optional embodiments, the microphone screening device of the present application further includes a humidifying device, which is used to humidify the test space inside the main housing 20, and maintain the humidity of the test space at more than 75%, more than 80%, more than 85%, or more than 90%. By increasing the humidity of the test space, it is more conducive to the screening of foreign matter and dirt in the silicon microphone, and the accuracy of the screening is improved.
[0053] In some optional embodiments, the microphone screening device of the present application may also be placed as a whole in a closed room with a humidity of more than 75%, more than 80%, more than 85%, or more than 90% to maintain the humidity of the working environment.
[0054] In some optional embodiments, the control device 27 can be configured to screen out qualified microphones by testing the distortion difference between adjacent sweep sound pressure points of the target microphone, the sensitivity difference between two tests under the same sound pressure, and the maximum sound pressure level (AOP).
[0055] In some optional embodiments, the control device 27 can be configured to Figure 4 The process steps shown in the figure are used to test and screen the target microphone. Figure 4 As shown, the steps of test screening may include:
[0056] Step 11, performing a sweep sound pressure comparison test on the target microphone, including: testing the distortion of the target microphone at multiple sweep sound pressure points, determining whether the distortion corresponding to each sweep sound pressure point exceeds a set range, and performing a difference comparison on the distortions of two adjacent sweep sound pressure points, determining whether the corresponding distortion difference exceeds a set range, so as to screen out qualified target microphones;
[0057] Step 12, performing a high sound pressure test on the qualified target microphone screened out in the previous step, including: testing a first sensitivity of the target microphone at a first preset sound pressure, then testing a second sensitivity of the target microphone at a second preset sound pressure, and then testing a third sensitivity of the target microphone at the first preset sound pressure again, wherein the first preset sound pressure is lower than the second preset sound pressure, and calculating whether the sensitivity difference between the first sensitivity and the third sensitivity exceeds a set range, thereby screening out the qualified target microphone;
[0058] Step 13, performing a fixed distortion sound pressure test on the qualified target microphone screened out in the previous step, including: testing to determine the maximum sound pressure level (AOP) of the target microphone, where the AOP is the sound pressure corresponding to 10% distortion of the output of the target microphone at 1KHz, and determining whether the AOP is lower than the control sound pressure level, thereby screening out qualified target microphones.
[0059] In some optional embodiments, the test to determine the AOP of the target microphone in step 13 may include: determining the maximum sound pressure level AOP of the target microphone using the distortion of the target microphone at multiple sweep sound pressure points obtained in step 11. In other optional embodiments, the test to determine the maximum sound pressure level AOP of the target microphone in step 13 may also be to perform another sound pressure test, and determine the AOP of the target microphone based on the test results.
[0060] In some optional implementations, the distortion of the target microphone at multiple sweep sound pressure points in step 11 includes: sweep testing the total harmonic distortion (THD) of the target microphone at multiple sweep sound pressure points from 94dB to 130dB, wherein the spacing between adjacent sweep sound pressure points may be 3dB (or may be 2dB or 4dB or other values). Exemplarily, the sweep sound pressure points include: 94dB, 97dB, 100dB, ..., 130dB.
[0061] In some optional implementations, in step 12, the first preset sound pressure is 94 dB, and the second preset sound pressure is 130 dB.
[0062] In some optional embodiments, the target microphone is a silicon microphone or an electret condenser microphone (ECM).
[0063] In some optional embodiments, the test steps of the present application can be performed in a closed space with a humidity of 75% or more. Further, the test steps can be performed in a closed space with a humidity of 80% or more, 85% or more, or 90% or more. By increasing the humidity of the environmental space, it is more conducive to the screening of foreign matter and dirt in the silicon microphone, and the accuracy of the screening is improved.
[0064] In some optional embodiments, the control device 27 includes a test board, which may include a CPU (central processing unit) and a memory. The memory stores a program, and the CPU may execute the program in the memory to perform steps 11 to 13 described above.
[0065] In some other optional implementations, the test board may be, for example, a FPGA (programmable array logic), and the FPGA executes the above steps 11 to 13. That is, the control device 27 may be a hardware circuit, and the above steps 11 to 13 are implemented by the hardware circuit.
[0066] As mentioned above, this application uses three different testing methods, namely high sound pressure test, swept amplitude sound pressure comparison test and fixed THD (total harmonic distortion) sound pressure test, to test and screen silicon microphones for defects such as foreign matter and dirt.
[0067] Fixed THD sound pressure test: Use AOP to test silicon microphones for foreign matter and dirt. AOP is the sound pressure level when THD exceeds 10%. If there is foreign matter or dirt on the silicon microphone MEMS diaphragm, the impact on THD will become greater, and the acoustic overload point AOP will also be affected. The performance of the silicon microphone can be determined by controlling the AOP. If it is lower than the controlled sound pressure level, it is poor, so that foreign matter, dirt and other defects in the silicon microphone can be screened out.
[0068] Sweep sound pressure comparison test: Use Delta THD method to test silicon microphones for foreign matter and dirt. Sweep the THD of silicon microphones at 94dB to 130dB sound pressure points, and compare the difference between the THD values tested at two adjacent sound pressure points. If there is foreign matter, the THD will increase at a certain sound pressure when sweeping, and the difference between the THD value and the adjacent sweep point will exceed the set range, which will determine that the silicon microphone is defective and screen out foreign matter and dirt.
[0069] High sound pressure test: Use the Shock Test method to test the silicon microphone for foreign matter. First, use 94dB sound pressure to test the sensitivity of the silicon microphone, and then use 130dB sound pressure to test the silicon microphone. The foreign matter may be on the MEMS diaphragm, and then it does not touch the MEMS back electrode. The sound pressure can cause the foreign matter to short-circuit between the MEMS diaphragm and the back electrode. At this time, the sensitivity of the silicon microphone will become low. Then use 94dB sound pressure to test the sensitivity of the silicon microphone. Compare the sensitivity difference of the two 94dB tests. If it exceeds the range of the difference setting, it is bad. In this way, the silicon microphone foreign matter can be screened out.
[0070] As described above, this application proposes a microphone screening device. The test lower pressure motor of the device is responsible for pressing the test upper needle seat with the test lower needle seat, the test upper needle seat is responsible for maintaining a seal with the test lower needle seat, the test sound card is responsible for making sound, the power amplifier amplifies the sound, and outputs it through the speaker. The test board is responsible for calculating the process and results of the product test. Optionally, the device of this application uses a 16-channel test system, which can test 16pcs of products at a time, and the products can be placed upside down during testing.
[0071] Through the above three testing methods, this application can accurately test the problems of dirt, foreign matter and poor performance of silicon microphone MEMS chips, and screen out qualified microphones. Compared with the existing technology, this application improves the accuracy of testing problems such as dirt, foreign matter and poor performance of MEMS chips, avoids the outflow of slightly defective products, and improves the production yield.
[0072] refer to Figure 5 To facilitate the understanding and implementation of the present application, the specific operation process of the microphone screening device of the present application is further described below in conjunction with a specific embodiment. Figure 5 As shown, the specific operation process may include the following steps:
[0073] Test the upper needle seat by pressing it down to test the sound of the speaker in the sound cavity;
[0074] The software sends a start test command;
[0075] After the test board is powered on, you can test the product current first;
[0076] The test software sends a sweep command, the sound card makes a sound, the amplifier makes a loud sound, the speaker outputs the sound, and the standard microphone (standard microphone stick) monitors the sound pressure;
[0077] Test the distortion of each sweep point to determine whether the distortion exceeds the set value;
[0078] Compare the distortion of adjacent scanning points, calculate the distortion difference, and determine whether the distortion difference exceeds the set range;
[0079] Then test the sensitivity of the silicon microphone with a 94dB sound pressure, then test the sensitivity with a 130dB sound pressure, and then test the sensitivity of the silicon microphone again with a 94dB sound pressure, and compare the difference between the two 94dB sensitivities to determine whether the sensitivity difference exceeds the set range;
[0080] Finally, determine what sound pressure the silicon microphone's 10% THD corresponds to.
[0081] The test is completed, the test results are determined, and the needle seat is lifted during the test.
[0082] In the above, the technical solution of the present application is described in detail through specific embodiments. In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.
[0083] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. A person skilled in the art may modify the technical solutions described in the above embodiments, or replace some of the technical features therein by equivalents; and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and protection scope of the technical solutions of the embodiments of the present application.
Claims
1. A microphone screening device, characterized in that: include: A test fixture, wherein a test sound cavity is formed inside the test fixture, and a speaker is arranged in the test sound cavity; A downward pressing motor is arranged above the test fixture; A test lower needle holder, which is arranged on the test fixture and has a placement groove for accommodating a target microphone; A test upper needle holder, connected to the push-down motor, having a test needle for contacting a target microphone, capable of moving under the drive of the push-down motor, and forming a sealed accommodation cavity for accommodating the target microphone with the test lower needle holder when pressed down onto the test lower needle holder, wherein the sealed accommodation cavity is communicated with the test sound cavity; A driving device, used for driving the speaker to produce sound; A control device is connected to the driving device, the pressing motor and the test upper needle seat, and is used to control the driving device to drive the speaker to sound, control the pressing motor to drive the test upper needle seat to be pressed down onto the test lower needle seat, and perform test screening on the target microphone by taking the test of the test upper needle seat.
2. The microphone screening device according to claim 1, characterized in that The test lower needle holder includes 16 placement grooves for placing 16 target microphones, and the control device is configured to complete the test screening of 16 target microphones at one time.
3. The microphone screening device according to claim 1, characterized in that A standard microphone is also provided in the test sound cavity, and the standard microphone is used to monitor whether the sound emitted by the speaker meets the requirements.
4. The microphone screening device according to claim 3, characterized in that The test sound cavity is divided into a front cavity and a rear cavity. The speaker is installed in the rear cavity and emits sound to the front cavity. The standard microphone is installed in the front cavity. The front cavity is communicated with the sealed accommodating cavity.
5. The microphone screening device according to claim 1, characterized in that: The target microphone is a silicon microphone or an electret condenser microphone.
6. The microphone screening device according to claim 1, characterized in that: The test lower needle seat is provided with a sound hole connecting the test sound cavity and the sealed accommodating cavity, and the sound hole includes: A first sound hole is formed inside the placement groove; and / or, The second sound hole is formed outside the placement groove.
7. The microphone screening device according to claim 1, characterized in that The driving device comprises: The test sound card is configured to connect to an external sound source and convert and process the sound signal emitted by the external sound source; The power amplifier is connected to the test sound card and is configured to amplify the sound signal converted and processed by the test sound card and output the amplified sound signal to the speaker to drive the speaker to make sound.