Head-mounted eye myoelectricity measuring device

Abstract

The invention belongs to the field of biomedical signal detection and electronic circuits, and particularly relates to a head-mounted eye myoelectricity measuring device which comprises an eye myoelectricity signal acquisition module, a data processing module, a signal transmission module and a power module. By arranging the input signal processing circuit, the primary amplification circuit and the secondary amplification circuit, multi-stage high-gain amplification is achieved, the detection precision of eye electromyographic signals is effectively improved, and the system is suitable for detection of weak eye electromyographic signals; by arranging low-pass filter capacitors C1, C2 and C41 and providing reference voltage, interference of external high-frequency noise and power supply fluctuation on the eye electromyographic signals is reduced, and the accuracy and reliability of eye electromyographic signal measurement are ensured.

Description

Technical Field

[0001] The present invention belongs to the field of biomedical signal detection and electronic circuits, and specifically relates to a head-mounted eye myoelectric measurement device. The device is used to detect and amplify eye myoelectric signals and is suitable for use in biomedicine, ophthalmology diagnosis, eye movement analysis and other occasions. Background Art

[0002] At present, the measurement of ocular electromyography (EOG) signals is widely used in the fields of eye movement detection, gaze tracking and ophthalmic diagnosis. Ocular electromyography is a weak bioelectric signal, which is usually easily interfered by external noise, and has low signal amplitude and low frequency, which puts high demands on signal amplification and noise suppression. Traditional amplifier circuits are difficult to meet the requirements of high gain, low noise and high stability at the same time, so existing equipment has great limitations in measurement accuracy and anti-interference.

[0003] In order to improve the accuracy of eye muscle electrogram signal measurement, the existing technology usually adopts a single-stage amplifier circuit or a simple passive filter to amplify and filter. However, when faced with weak and low-frequency eye muscle electrogram signals, such circuits often cannot provide sufficient gain and signal-to-noise ratio. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problems existing in the background technology, and for this purpose, a head-mounted eye myoelectricity measuring device is provided.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A head-mounted eye myoelectricity measuring device comprises an eye myoelectricity signal acquisition module, a data processing module, a signal transmission module and a power supply module;

[0007] Eye muscle electrical signal acquisition module, used to collect electrical signals of eye muscles;

[0008] A data processing module is used to convert the collected electrical signals into digital signals and transmit them to the signal transmission module;

[0009] A signal transmission module is used to transmit digital signals to a host computer;

[0010] The power module is used to supply power to the eye muscle electromyography signal acquisition module, the data processing module, and the signal transmission module.

[0011] The following is a technical solution further defined in the present invention, wherein the eye muscle electrical signal acquisition module comprises an input signal processing circuit, a primary amplification circuit and a secondary amplification circuit;

[0012] The input signal processing circuit includes diodes VD1, VD2, resistors R1, R2;

[0013] The primary amplifier circuit includes a differential amplifier U4;

[0014] The secondary amplifier circuit includes an operational amplifier U1;

[0015] Wherein, diodes VD1 and VD2 are connected in reverse parallel between input terminal 1 and input terminal 2, a resistor R1 is connected between one end of diode VD2 and pin 2 of differential amplifier U4, a resistor R2 is connected between the other end of diode VD2 and pin 3 of differential amplifier U4, resistors R5 and R6 are connected in series between pin 1 and pin 8 of differential amplifier U4, and an external gain adjustment resistor is connected between resistors R5 and R6;

[0016] A resistor R9 is connected between pin 6 of the differential amplifier U4 and pin 2 of the operational amplifier U1 , and a resistor R10 is connected between pin 1 and pin 2 of the operational amplifier U1 .

[0017] The following is a technical solution further defined by the present invention, wherein the input signal processing circuit further includes bypass capacitors C1 and C2;

[0018] One end of the bypass capacitor C1 is connected to the line between the resistor R1 and the pin 2 of the differential amplifier U4, and the other end of the bypass capacitor C1 is grounded;

[0019] One end of the bypass capacitor C2 is connected to the line between the resistor R2 and the pin 3 of the differential amplifier U4, and the other end of the bypass capacitor C2 is grounded.

[0020] The following is a technical solution further defined by the present invention: a capacitor C4 is connected between pin 2 and pin 3 of the differential amplifier U4.

[0021] The following is a technical solution further defined in the present invention: Pin 7 of the differential amplifier U4 is connected to a power supply voltage, and the power supply voltage is grounded through capacitors C5 and C30 connected in parallel.

[0022] The following is a technical solution further defined in the present invention: Pin 3 and Pin 5 of the operational amplifier U1 are both connected to a reference voltage.

[0023] The following is a technical solution further defined in the present invention: Pin 8 of the operational amplifier U1 is connected to a power supply voltage, and the power supply voltage is grounded through a capacitor C12.

[0024] The following is a technical solution further defined in the present invention: a capacitor C41 is connected in parallel between both ends of the resistor R10.

[0025] The following is a technical solution further defined by the present invention. The data processing module adopts a main control circuit with STM32F103C8T6 as the core. By using the ADC sampling interface of the chip, the sampling signal of the eye muscle electromyography signal acquisition module is connected to the ADC pin of STM32F103C8T6 for analog-to-digital conversion.

[0026] The following is a technical solution further defined by the present invention, which also includes a device shell and a headband, wherein the device shell is made of lightweight carbon fiber material by 3D printing, and the headband is designed as a headband with adjustable buckles.

[0027] Compared with the prior art, the present invention has the following technical effects:

[0028] The present invention realizes multi-stage high-gain amplification by arranging an input signal processing circuit, a primary amplification circuit and a secondary amplification circuit, effectively improves the detection accuracy of eye muscle electric signals, and is suitable for the detection of weak eye muscle electric signals; by arranging low-pass filter capacitors C1, C2, C41 and providing a reference voltage, the interference of external high-frequency noise and power supply fluctuation on the eye muscle electric signals is reduced, and the accuracy and reliability of the eye muscle electric signal measurement are ensured.

[0029] The present invention is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 is a connection relationship diagram of the input signal processing circuit in the present invention;

[0032] Figure 2 It is a connection relationship diagram of the primary amplifier circuit in the present invention;

[0033] Figure 3 It is a connection relationship diagram of the secondary amplifier circuit in the present invention. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0035] like Figure 1-3 As shown, this embodiment provides a head-mounted eye muscle electromyography measurement device, which mainly includes an eye muscle electromyography signal acquisition module, a data processing module, a signal transmission module and a power module. The eye muscle electromyography signal acquisition module is responsible for collecting the electrical signals of the eye muscles, and the data processing module converts the collected signals into digital signals and transmits them to the signal transmission module. The signal transmission module transmits the digital signals to the host computer for processing.

[0036] The eye muscle electromyography signal acquisition module includes an input signal processing circuit, a primary amplification circuit, a secondary amplification circuit, and a tertiary amplification and sampling frequency limiting circuit. The three-stage amplification structure is adopted, which can amplify the surface electromyography signal by about 2000 times. The eye muscle electromyography signal acquisition module is specifically a sensor or electrode. The high sensitivity and wide-band response characteristics of the sensor ensure the sensitivity and accuracy of weak electromyography signals, so that the device can capture subtle changes in eye muscle electromyography signals.

[0037] 1. Input signal processing circuit

[0038] like Figure 1 As shown, the input signal processing circuit is composed of diodes VD1, VD2, resistors R1, R2, capacitors C1, C2, C4, etc.

[0039] Among them, diodes VD1 and VD2 are used as input protection diodes and are connected in reverse parallel between the "Right1" input terminal and the "Left1" input terminal. Diodes VD1 and VD2 will be turned on when the input signal is too high, thereby limiting the input voltage and protecting the rear amplifier from overvoltage shock.

[0040] Resistors R1 and R2 are connected in series in the input signal path as input resistors to limit the input current and achieve impedance matching to prevent the signal source from being affected by the load.

[0041] Capacitors C1 and C2 are used as bypass capacitors, connected in parallel between the input terminal and the ground to filter out high-frequency noise and ensure the purity of the amplifier input signal. They are suitable for low-frequency signal processing.

[0042] 2. Primary amplifier circuit

[0043] Function: INA326 is a precision differential amplifier used to preliminarily amplify weak eye muscle electrical signals.

[0044] Amplification: Amplify the eye muscle electrical signal by about 5 times to facilitate subsequent processing.

[0045] Features: It has high common mode rejection ratio and low noise characteristics, suitable for the initial amplification of biological signals.

[0046] like Figure 2As shown, the primary amplifier circuit is composed of a differential amplifier U4, resistors R5, R6, capacitors C5, C30, etc.

[0047] Among them, the differential amplifier U4 uses INA326, and its pins 1-8 are R1, VIN-, VIN+, VDD- / GND, R2, V0, VDD+, and R1 respectively. The differential amplifier U4 is configured with a gain of 5 times to amplify the weak eye muscle electromyography differential signal and suppress common-mode noise. The gain is determined by the external resistor between pins 1 and 8 of the differential amplifier U4 (not shown, the default gain is 5 times).

[0048] 3. Secondary amplifier circuit

[0049] Function: AD8572 is a high speed operational amplifier used to further amplify the signal after preliminary amplification.

[0050] Magnification: The total magnification is approximately 400 times.

[0051] Features: It has the characteristics of fast response and high precision, and can effectively amplify weak signals.

[0052] like Figure 3 As shown, the secondary amplifier circuit is composed of an operational amplifier U1, resistors R9, R10, capacitors C12, C41, etc.

[0053] Among them, operational amplifier U1 uses ADS872, and its pins 1-8 are OUTA, -INA, +INA, VDD- / GND, +INB, -INB, OUTB, and VDD+ respectively. Operational amplifier U1 achieves 400 times high gain amplification, and gain control is achieved through feedback resistor R10 and input resistor R9, further amplifying the signal passing through the primary amplifier circuit to a measurable level. Pins 3 and 5 of operational amplifier U1 are both connected to the reference voltage. Filter capacitor C41 and feedback resistor R10 are used in combination to stabilize the high gain amplifier U1 and avoid high frequency noise and signal self-excitation.

[0054] 4. Three-stage amplification and sampling frequency limiting circuit

[0055] Function: The last AD8572 is not only used for the final amplification of the signal, but also limits the sampling frequency of the signal by configuring its peripheral circuit.

[0056] Sampling frequency limitation: The sampling frequency of the signal is limited to 5 Hz to meet specific application requirements.

[0057] Features: Precise control of sampling frequency can be achieved by adjusting the feedback network and capacitor value.

[0058] The data processing module uses the main control circuit with STM32F103C8T6 as the core. By using the ADC sampling interface of the chip, the data processing module can be directly connected to the analog signal source to be collected. The sampling signal of the eye muscle electromyography signal acquisition module is connected to the ADC pin of STM32F103C8T6 for analog-to-digital conversion. The ADC converts the analog signal into a digital signal and transmits it to the microcontroller through the bus interface for processing and storage.

[0059] The signal transmission module adopts Bluetooth 4.0 technology, supports BLE protocol, and can achieve high-speed data transmission with low power consumption.

[0060] The power module uses a power supply circuit with the ht7133 voltage regulator as the core, replacing the traditional boost circuit. The power supply battery is charged through the Type-C interface.

[0061] The device shell is made of lightweight carbon fiber material 3D printing, reducing the overall weight.

[0062] Designed with an adjustable headband to accommodate different head shapes and sizes.

[0063] The device's lead wires are adjustable in length, allowing the user to fine-tune the position of the electrodes based on their personal facial features to ensure optimal signal capture.

[0064] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the above disclosed methods and technical contents without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, all equivalent changes made according to the shape, structure and principle of the present invention without departing from the content of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A head-mounted electromyography measuring device, characterized in that: It includes an eye muscle electrical signal acquisition module, a data processing module, a signal transmission module and a power supply module; Eye muscle electrical signal acquisition module, used to collect electrical signals of eye muscles; A data processing module is used to convert the collected electrical signals into digital signals and transmit them to the signal transmission module; A signal transmission module is used to transmit digital signals to a host computer; The power module is used to supply power to the eye muscle electromyography signal acquisition module, the data processing module, and the signal transmission module.

2. A head-mounted eye myoelectricity measuring device as claimed in claim 1, characterized in that: The eye muscle electrical signal acquisition module includes an input signal processing circuit, a primary amplification circuit and a secondary amplification circuit; The input signal processing circuit includes diodes VD1, VD2, resistors R1, R2; The primary amplifier circuit includes a differential amplifier U4; The secondary amplifier circuit includes an operational amplifier U1; Wherein, diodes VD1 and VD2 are connected in reverse parallel between input terminal 1 and input terminal 2, a resistor R1 is connected between one end of diode VD2 and pin 2 of differential amplifier U4, a resistor R2 is connected between the other end of diode VD2 and pin 3 of differential amplifier U4, resistors R5 and R6 are connected in series between pin 1 and pin 8 of differential amplifier U4, and an external gain adjustment resistor is connected between resistors R5 and R6; A resistor R9 is connected between pin 6 of the differential amplifier U4 and pin 2 of the operational amplifier U1 , and a resistor R10 is connected between pin 1 and pin 2 of the operational amplifier U1 .

3. A head-mounted eye myoelectricity measuring device as claimed in claim 2, characterized in that: The input signal processing circuit also includes bypass capacitors C1 and C2; One end of the bypass capacitor C1 is connected to the line between the resistor R1 and the pin 2 of the differential amplifier U4, and the other end of the bypass capacitor C1 is grounded; One end of the bypass capacitor C2 is connected to the line between the resistor R2 and the pin 3 of the differential amplifier U4, and the other end of the bypass capacitor C2 is grounded.

4. A head-mounted eye myoelectricity measuring device as claimed in claim 2, characterized in that: A capacitor C4 is connected between pin 2 and pin 3 of the differential amplifier U4.

5. A head-mounted eye myoelectricity measuring device as claimed in claim 2, characterized in that: Pin 7 of the differential amplifier U4 is connected to a power supply voltage, and the power supply voltage is grounded through capacitors C5 and C30 connected in parallel.

6. A head-mounted eye myoelectricity measuring device as claimed in claim 2, characterized in that: Pin 3 and pin 5 of the operational amplifier U1 are both connected to a reference voltage.

7. A head-mounted eye myoelectricity measuring device as claimed in claim 2, characterized in that: Pin 8 of the operational amplifier U1 is connected to a power supply voltage, and the power supply voltage is grounded through a capacitor C12.

8. A head-mounted eye myoelectricity measuring device as claimed in claim 2, characterized in that: The two ends of the resistor R10 are connected in parallel with a capacitor C41.

9. A head-mounted eye myoelectricity measuring device as claimed in claim 1, characterized in that: The data processing module adopts a main control circuit with STM32F103C8T6 as the core, and connects the sampling signal of the eye muscle electrosignal acquisition module to the ADC pin of STM32F103C8T6 by using the ADC sampling interface of the chip to perform analog-to-digital conversion.

10. A head-mounted eye myoelectricity measuring device as claimed in claim 1, characterized in that: It also includes a device shell and a headband, wherein the device shell is made of lightweight carbon fiber material by 3D printing, and the headband is designed as a headband with adjustable buckles.

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