Tool for simulating human body contact impedance

Abstract

The utility model discloses a tool for simulating human body contact impedance, which comprises a host, a power supply, an acquisition box, a connector and a contact impedance detection tool structure. The contact impedance detection tool structure comprises a plastic upper shell, a plastic lower shell, a first electrode, a second electrode, a third electrode, a first slide rheostat, a second slide rheostat, a third slide rheostat and a detection sensor. The first electrode is arranged to simulate a human body forehead electrode. And the second electrode is arranged as a human ear process simulating electrode. And the third electrode is a simulated temporal electrode. The detection sensor sequentially comprises a first contact, a second contact, a third contact and a plug, wherein the second contact is connected with the first contact, is arranged on the human body ear process simulating electrode and is in contact with the human body ear process simulating electrode, the third contact is connected with the second contact, is arranged on the human body ear process simulating electrode and is in contact with the human body ear process simulating electrode, and the plug is connected with the second contact. The electroencephalogram sensor inspection device has the effect of improving the electroencephalogram sensor inspection efficiency.

Description

Technical Field

[0001] This utility model relates to the field of medical devices, and in particular to a tooling for simulating human body contact impedance to detect the quality of electroencephalogram (EEG) sensors. Background Technology

[0002] The primary purpose of EEG sensors is to collect brainwave signals and transmit the data to an EEG control unit in real time. Currently, most commercially available EEG sensors rely on the contact impedance between the electrodes and the skin; therefore, measuring this contact impedance is crucial for quantitatively evaluating sensor quality. However, because skin contact impedance varies between individuals and at different times—for example, even within the same person—existing EEG sensors lack the quantitative ability to determine the quality of each batch. Utility Model Content

[0003] In view of the above problems, the purpose of this utility model is to provide a tooling for simulating human body contact impedance to improve the testing efficiency of EEG sensors.

[0004] To achieve the above objectives, this utility model provides a fixture for simulating human body contact impedance, comprising a main unit, a power supply and a data acquisition box connected to the main unit, a connector on the data acquisition box, and a contact impedance detection fixture structure connected to the connector. The main unit includes a housing, a PCB board inside the housing, and a display screen connected to the PCB board on the housing. The contact impedance detection fixture structure includes a plastic upper shell, a plastic lower shell, a first electrode, a second electrode, and a third electrode sequentially arranged on the plastic upper shell, a first sliding rheostat connected to the first electrode on the plastic upper shell, a second sliding rheostat connected to the second electrode on the plastic upper shell, a third sliding rheostat connected to the third electrode on the plastic upper shell, and a detection sensor on one side of the plastic upper shell. The first electrode is configured to simulate the forehead of a human body. The second electrode is configured to simulate the auricular process of a human body. The third electrode is configured to simulate the temporal region. The detection sensor sequentially includes a first contact point on a simulated human forehead electrode that contacts the simulated human forehead electrode; a second contact point connected to the first contact point on a simulated human earlobe electrode that contacts the simulated human earlobe electrode; a third contact point connected to the second contact point that contacts the simulated human earlobe electrode; and a plug connected to the second contact point. The plug is connected to a connector.

[0005] In some implementations, the detection sensor is a triangular pattern detection sensor. In a triangular pattern detection sensor, the third contact is connected to the first and second contacts respectively, and the first and second contacts are then connected in a triangular relationship.

[0006] In some embodiments, the impedance between the first contact and the second contact is impedance R3, the impedance between the first contact and the third contact is impedance R2, and the impedance between the third contact and the second contact is impedance R1.

[0007] In some implementations, the detection sensor is a star-shaped detection sensor. In a star-shaped detection sensor, the first contact, the second contact, and the third contact are connected at a single point, exhibiting a radiating connection.

[0008] In some implementations, the impedance of the first contact is impedance r1. The impedance of the second contact is impedance r2. The impedance of the third contact is impedance r3. Impedances r1, r2, and r3 are displayed on the host computer's screen.

[0009] In some implementations, impedance calibration points are provided on the plastic upper shell.

[0010] The beneficial effects of this invention are that it improves the inspection efficiency of EEG sensors and offers convenience and flexibility. Because the improved fixture has an impedance verification function, it reduces the impact of fixture impedance changes on the finished EEG sensor inspection. By using a quantitative impedance value to replace the varying impedance of the human body, it avoids the influence of human body differences on contact impedance measurement, accurately displaying the contact impedance of the EEG sensor and improving the finished EEG sensor inspection efficiency. Attached Figure Description

[0011] Figure 1 It is a structural diagram of the utility model;

[0012] Figure 2 for Figure 1 The diagram shows a structural schematic of the contact impedance detection fixture.

[0013] Figure 3 This is a schematic diagram of the contact impedance detection fixture structure in this utility model;

[0014] Figure 4 This is a schematic diagram of the triangular pattern detection sensor in this utility model;

[0015] Figure 5 This is a schematic diagram of the star pattern detection sensor in this utility model. Detailed Implementation

[0016] The utility model will now be described in further detail with reference to the accompanying drawings.

[0017] like Figure 1-5As shown, a fixture for simulating human body contact impedance includes a main unit 01, a power supply 02 connected to the main unit 01, a data acquisition box 03, a connector 06 on the data acquisition box 03, and a contact impedance detection fixture structure 04 connected to the connector 06. The main unit 01 includes a housing, a PCB board inside the housing, and a display screen connected to the PCB board on the housing. The contact impedance detection fixture structure 04 includes a plastic upper shell 41, a plastic lower shell 42, a first electrode 43, a second electrode 44, and a third electrode 45 sequentially arranged on the plastic upper shell 41, a first sliding rheostat 46 connected to the first electrode 43 on the plastic upper shell 41, a second sliding rheostat 47 connected to the second electrode 44 on the plastic upper shell 41, a third sliding rheostat 48 connected to the third electrode 45 on the plastic upper shell 41, and a detection sensor 49 on one side of the plastic upper shell 41. The first electrode 43, the second electrode 44, and the third electrode 45 are respectively wired to the first sliding rheostat 46, the second sliding rheostat 47, and the third sliding rheostat 48. The first electrode 43 is configured as a simulated human forehead electrode. The second electrode 44 is configured as a simulated human auricular protuberance electrode. The third electrode 45 is configured as a simulated temporal electrode. The detection sensor 49 sequentially includes a first contact 491 on the simulated human forehead electrode that contacts the simulated human forehead electrode, a second contact 492 connected to the first contact 491 and connected to the simulated human auricular protuberance electrode that contacts the simulated human auricular protuberance electrode, a third contact 493 connected to the second contact 492 and connected to the simulated human auricular protuberance electrode, and a plug 05 connected to the second contact 492. The plug 05 is connected to the connector 06. The detection sensor 49 is a triangular pattern detection sensor 49. The triangular pattern detection sensor 49 has its third contact 493 connected to the first contact 491 and the second contact 492 respectively, and the connection between the first contact 491 and the second contact 492 forms a triangular relationship. The impedance between the first contact 491 and the second contact 492 is impedance R3, the impedance between the first contact 491 and the third contact 493 is impedance R2, and the impedance between the third contact 493 and the second contact 492 is impedance R1. The detection sensor 49 is also a star pattern detection sensor 49. In the star pattern detection sensor 49, the connections of the first contact 491, the second contact 492, and the third contact 493 converge at a single point, forming a radiating connection. The impedance of the first contact 491 is impedance r1. The impedance of the second contact 492 is impedance r2. The impedance of the third contact 493 is impedance r3. Impedances r1, r2, and r3 are displayed on the display screen of the host 01. An impedance calibration point 07 is provided on the plastic upper shell 41.

[0018] The impedance display principle implemented by host 01 is as follows:

[0019] The PCB board includes a small voltage excitation circuit, a current-limiting resistor, a gain measurement circuit, a switching circuit, a preamplifier, and an ADC. The three electrode plates are connected to the non-inverting input, the inverting input, and the driver circuit of the preamplifier, respectively.

[0020] There are two models that can simulate the three-electrode detection impedance of the sensor: the triangular mode detection sensor 49 and the star mode detection sensor, and the two can be converted to each other.

[0021] The three electrodes are the forehead electrode, the auricular process electrode, and the temporal electrode. In the mid-star pattern detection sensor, the impedance between the forehead and the auricular process is R3, the impedance between the forehead and the temporal region is R2, and the impedance between the temporal region and the auricular process is R1. In the star pattern detection sensor: the conduction impedance of the forehead is r1, the conduction impedance of the auricular process is r2, and the conduction impedance of the temporal region is r3; as follows. Figure 4 and 5 As shown.

[0022] They satisfy the following relationship:

[0023]

[0024] Step 1: A 110Hz, 3Vpp square wave positive AC signal is generated from the PWM port of the MCU. It is then converted into a 20mVpp, 110Hz square wave excitation signal through a DC blocking voltage divider network, which serves as the excitation signal source for the impedance measurement circuit.

[0025] Step 2: Determine that the electrode is in the non-connected state, and simultaneously enable the impedance measurement circuit and the amplification factor measurement circuit. Using the MCU configuration switching circuit, connect the excitation signal source to the non-inverting input of the preamplifier through a 1MΩ current-limiting resistor. Measure using an internal standard 2kΩ resistor, and calculate the 110Hz frequency component at the amplifier output as V0 using an ADC. Then, obtain the amplification factor A of the preamplifier at 110Hz.

[0026]

[0027] Where R0 is 2k and V0 is the 110Hz frequency component sampled by the ADC.

[0028] From the above formula, we get:

[0029]

[0030] Step 3: With the electrode plate in normal testing condition, enable the impedance measurement circuit and disable the amplification factor measurement circuit. Configure the switching circuit via the MCU to connect the excitation signal source to the non-inverting input of the preamplifier (forehead) through a 1MΩ current-limiting resistor. Ground the earlobe electrode. Calculate the 110Hz frequency component at the amplifier output as V1 using the ADC. Then, the impedance between the two inputs of the preamplifier is:

[0031]

[0032] V1 is the 110Hz frequency component sampled by the ADC.

[0033] Step 4: With the electrode plates in normal testing condition, enable the impedance measurement circuit and disable the amplification factor measurement circuit. Configure the switching circuit via the MCU to connect the excitation signal source to the non-inverting input of the preamplifier (forehead) through a 1MΩ current-limiting resistor. Ground both the auricular and temporal electrodes. Calculate the 110Hz frequency component at the amplifier output as V2 using the ADC. Then, the impedance between the two inputs of the preamplifier is:

[0034]

[0035] V2 is the 110Hz frequency component sampled by the ADC.

[0036] Step 5: With the electrode plates in normal testing condition, enable the impedance measurement circuit and disable the amplification factor measurement circuit. Configure the switching circuit via the MCU to connect the excitation signal source to the inverting input of the preamplifier (i.e., the auricular protuberance) through a 1MΩ current-limiting resistor. Ground both the forehead and temporal electrodes. Calculate the 110Hz frequency component at the amplifier output as V3 using the ADC. Then, the impedance between the two inputs of the preamplifier is:

[0037]

[0038] Step 6: Let the conductances Y1 = 1 / Z1; Y2 = 1 / Z2; Y3 = 1 / Z3. The calculated impedance of the triangular model is:

[0039]

[0040] The impedance of the star model can be calculated from the triangular model as follows:

[0041]

[0042] Step 7: Display r1, r2, and r3 on the host 01 screen.

[0043] Sensor finished product inspection standards:

[0044] The host 01 displays an impedance less than the acceptable set value, indicating that the sensor quality is acceptable.

[0045] The above descriptions are merely some embodiments of this utility model. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of this utility model, and all such modifications and improvements fall within the protection scope of this utility model.

Claims

1. A tooling for simulating human body contact resistance, characterized in that, The device includes a main unit, a power supply and a data acquisition box connected to the main unit, a connector on the data acquisition box and a contact impedance detection fixture connected to the connector; the main unit includes a housing, a PCB board inside the housing, and a display screen connected to the PCB board on the housing. The aforementioned contact impedance detection fixture structure includes a plastic upper shell, a plastic lower shell, a first electrode, a second electrode and a third electrode arranged sequentially on the plastic upper shell, a first sliding rheostat connected to the first electrode on the plastic upper shell, a second sliding rheostat connected to the second electrode on the plastic upper shell, a third sliding rheostat connected to the third electrode on the plastic upper shell, and a detection sensor on one side of the plastic upper shell. The first electrode is configured to simulate the forehead electrode of a human body; The second electrode is configured to simulate a human auricular protuberance electrode; The third electrode is configured to simulate a temporal electrode; The detection sensor includes, in sequence, a first contact point on a simulated human forehead electrode that contacts the simulated human forehead electrode, a second contact point connected to the first contact point on a simulated human auricular electrode that contacts the simulated human auricular electrode, a third contact point connected to the second contact point on a simulated human auricular electrode that contacts the simulated human auricular electrode, and a plug connected to the second contact point. The plug and connector are connected.

2. The tooling for simulating human body contact impedance according to claim 1, characterized in that, The detection sensor is a triangular pattern detection sensor; The triangular pattern detection sensor is configured such that the third contact is connected to the first and second contacts respectively, and the first and second contacts are connected in a triangular relationship.

3. The tooling for simulating human body contact impedance according to claim 2, characterized in that, The impedance between the first contact and the second contact is impedance R3, the impedance between the first contact and the third contact is impedance R2, and the impedance between the third contact and the second contact is impedance R1.

4. The tooling for simulating human body contact resistance according to claim 1, characterized in that, The detection sensor is a star-shaped detection sensor; The star-shaped detection sensor has three contacts—the first contact, the second contact, and the third contact—connected at the same point, forming a radiating connection.

5. The tooling for simulating human body contact impedance according to claim 4, characterized in that, The impedance of the first contact is impedance r1, the impedance of the second contact is impedance r2, and the impedance of the third contact is impedance r3; The impedances r1, r2, and r3 are displayed on the host computer's screen.

6. The tooling for simulating human body contact impedance according to claim 1, characterized in that, The plastic upper shell is provided with impedance calibration points.

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